Classifications

• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/20—Devices using solid inhalable precursors
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
  • A24F40/46—Shape or structure of electric heating means
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
  • A24F40/46—Shape or structure of electric heating means
  • A24F40/465—Shape or structure of electric heating means specially adapted for induction heating
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/50—Control or monitoring
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/50—Control or monitoring
  • A24F40/57—Temperature control

Definitions

• the present disclosure relates to an aerosol-generating system and a method of controlling an aerosol-generating system.
• Some known aerosol-generating systems comprise an aerosol-generating device and an aerosol-generating article comprising an aerosol-forming substrate.
• the aerosolgenerating device heats the aerosol-forming substrate of the aerosol-generating article to form an aerosol.
• Some known aerosol-generating devices comprise an internal heater for heating the aerosol-forming substrate from within the aerosol-forming substrate.
• using an internal heater to heat an outer portion of the aerosol-forming substrate sufficiently to form an aerosol may require heating the internal heater to a sufficiently high temperature that there is a risk of the internal heater overheating or burning an inner portion of the aerosol-forming substrate close to the internal heater.
• the use of an internal heater typically leads to an outer portion of the aerosol-forming substrate, furthest from the internal heater during use, not being heated to a sufficiently high temperature to form an aerosol. This means that the outer portion of the aerosolforming substrate is typically wasted.
• Some known aerosol-generating devices comprise an external heater for heating the aerosol-forming substrate from outside the aerosol-forming substrate.
• using an external heater to heat an inner portion of the aerosol-forming substrate sufficiently to form an aerosol may require heating the external heater to a sufficiently high temperature that there is a risk of the external heater overheating or burning the outer portion of the aerosol-forming substrate close to the external heater.
• the use of an external heater typically leads to an inner portion of the aerosol-forming substrate, furthest from the external heater during use, not being heated to a sufficiently high temperature to form an aerosol. This means that the inner portion of the aerosolforming substrate is typically wasted.
• the aerosol-generating system may comprise an internal heater.
• the internal heater may be configured to heat an aerosol-forming substrate from within the aerosol-forming substrate.
• the aerosol-generating system may comprise an external heater.
• the external heater may be configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate.
• the method may comprise controlling a supply of power to one or both of the internal heater and the external heater during a plurality of phases, the supply of power being different for at least two phases, or for each phase, of the plurality of phases.
• the aerosol-generating system comprises an internal heater configured to heat an aerosol-forming substrate from within the aerosol-forming substrate; and an external heater configured to heat the aerosol-forming substrate from outside the aerosolforming substrate.
• the method comprises controlling a supply of power to one or both of the internal heater and the external heater during a plurality of phases, the supply of power being different for at least two phases, or for each phase, of the plurality of phases.
• an aerosol-generating system may comprise an internal heater.
• the internal heater may be configured to heat an aerosol-forming substrate from within the aerosol-forming substrate.
• the aerosol-generating system may comprise an external heater.
• the external heater may be configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate.
• the aerosol-generating system may comprise a controller.
• the controller may be configured to control a supply of power to one or both of the internal heater and the external heater during a plurality of phases, the supply of power being different for at least two phases, or for each phase, of the plurality of phases.
• an aerosolgenerating system comprising: an internal heater configured to heat an aerosol-forming substrate from within the aerosol-forming substrate; an external heater configured to heat the aerosolforming substrate from outside the aerosol-forming substrate; and a controller.
• the controller is configured to control a supply of power to one or both of the internal heater and the external heater during a plurality of phases, the supply of power being different for at least two phases, or for each phase, of the plurality of phases.
• the aerosol-generating system of one or both of the first aspect and the second aspect may comprise an aerosol-generating device and an aerosol-generating article comprising the aerosol-forming substrate.
• the aerosol-generating device may comprise the external heater.
• the aerosol-generating device or article may comprise the internal heater.
• an aerosol-generating device for use as part of an aerosol-generating system.
• the aerosol-generating system may comprise the aerosol-generating device and an aerosol-generating article comprising an aerosol-forming substrate.
• the aerosol-generating system for example the device or article of the system, may comprise an internal heater.
• the internal heater may be configured to heat the aerosol-forming substrate from within the aerosol-forming substrate.
• the aerosol-generating device may comprise an external heater.
• the external heater may be configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate.
• the aerosol-generating device may comprise a controller.
• the controller may be configured to control a supply of power to one or both of the internal heater and the external heater during a plurality of phases, the supply of power being different for at least two phases, or for each phase, of the plurality of phases.
• an aerosolgenerating device for use as part of an aerosol-generating system.
• the aerosol-generating system comprises the aerosol-generating device and an aerosol-generating article comprising an aerosol-forming substrate.
• the aerosol-generating system for example the device or article of the system, comprises an internal heater configured to heat the aerosol-forming substrate from within the aerosol-forming substrate.
• the aerosol-generating device comprises: an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate; and a controller.
• the controller is configured to control a supply of power to one or both of the internal heater and the external heater during a plurality of phases, the supply of power being different for at least two phases, or for each phase, of the plurality of phases.
• presence of both an internal heater and an external heater may allow heating of the aerosol-forming substrate from within and from outside the aerosol-forming substrate. This may reduce a proportion of the aerosol-forming substrate which does not reach a sufficiently high temperature to form an aerosol in use, reducing waste.
• the supply of power being different for at least two phases, or for each phase, of the plurality of phases may allow tailoring of the temperature profiles of the internal and external heaters during various phases of a usage session.
• the supply of power during a pre-heating phase may allow rapid heating of the aerosol-forming substrate to reduce a time required for a first puff on the system.
• the device referred to in the second aspect may be the device of the third aspect.
• the system referred to in the third aspect may be the system of the second aspect.
• the controller of the second or third aspect may be configured to carry out a method according to the first aspect.
• the controller may be configured to carry out any of the method steps described below.
• references herein to the system, the device, the article and the substrate may refer to the aerosol-generating system, the aerosol-generating device, the aerosol-generating article, and the aerosol-forming substrate respectively.
• the device may be configured to engage with, for example receive at least a portion of, the article.
• the device may comprise a housing.
• the device may comprise a chamber.
• the housing may define the chamber.
• the chamber may be configured to receive at least a portion of the article.
• the chamber may have a base.
• the chamber may have an open end. The open end may oppose the base.
• the device may be configured to receive at least the portion of the article into the chamber through the open end of the chamber.
• the device may comprise the controller.
• the system for example the device of the system, may comprise at least one power supply. Future references to “a power supply” or “the power supply” should be considered references to the at least one power supply. References herein to a supply of power may refer to a supply of power from the power supply. Controlling a supply of power to the internal heater or to the external heater may comprise or be controlling a supply of power, for example controlling one or both of current and voltage, from the at least one power supply to the internal heater or to the external heater. References herein to increasing or decreasing a temperature of the internal heater may be a result of controlling a supply of power to one or both of the internal heater and the external heater. References herein to increasing or decreasing a temperature of the external heater may be a result of controlling a supply of power to the external heater.
• the external heater may be or comprise an inductor such as an inductor coil.
• the terms “controlling a supply of power to the external heater” and “controlling a supply of power to the inductor” may be used interchangeably.
• the internal heater may be or comprise a susceptor.
• the terms “controlling a supply of power to the internal heater” and “controlling a supply of power to the susceptor” may be used interchangeably. This interchangeable use of terms applies to the description and the examples listed below.
• controlling a supply of power to the external heater may be used to control heating of the internal heater.
• Controlling a supply of power to the internal heater may include inductive power transfer from an inductor to the internal heater.
• the external heater may be or comprise an electrically resistive heater, also referred to as a Joule-effect heater.
• the external heater may be or comprise an inductor such as an inductor coil.
• the internal heater may be an electrically resistive heater.
• the internal heater may be or comprise a susceptor for being inductively heated. As such, there are numerous options for the internal heater and the external heater. Some more complete options are explored briefly in the five paragraphs below.
• the device comprises the internal heater; the device comprises the external heater; the internal heater is or comprises a susceptor; and the external heater is or comprises an inductor such as an inductor coil.
• power may be supplied to the inductor so as to resistively heat the inductor to allow the inductor to act as the external heater, and power may be supplied to the inductor to inductively heat the susceptor to allow the susceptor to act as the internal heater.
• the inductor being able to both inductively heat the internal heater and be resistively heated to act as the external heater may allow heating of the aerosol-forming substrate from inside and outside with an arrangement that is no more complex than a typical induction heating arrangement.
• the device comprises the external heater; the article comprises the internal heater; the internal heater is or comprises a susceptor; and the external heater is or comprises an inductor such as an inductor coil.
• the inductor being able to both inductively heat the internal heater and be resistively heated to act as the external heater may allow heating of the aerosol-forming substrate from inside and outside with an arrangement that is no more complex than a typical induction heating arrangement.
• the device comprises the internal heater; the device comprises the external heater; the internal heater is an electrically resistive heater; and the external heater is an electrically resistive heater.
• the device comprises the internal heater; the device comprises the external heater; the device comprises an inductor distinct from the external heater; the external heater is an electrically resistive heater; and the internal heater is or comprises a susceptor.
• power may be supplied to the inductor to inductively heat the susceptor to allow the susceptor to act as the internal heater.
• the device comprises the external heater; the device comprises an inductor distinct from the external heater; the article comprises the internal heater; the external heater is an electrically resistive heater; and the internal heater is or comprises a susceptor.
• power may be supplied to the inductor to inductively heat the susceptor to allow the susceptor to act as the internal heater.
• the plurality of phases may comprise any one, or any combination, or all, of a pre-heating phase, a cooling phase, a first phase, and a second phase.
• the plurality of phases may all occur during a single usage session.
• the method may comprise: during a first phase, controlling a supply of power to one or both of the internal heater and the external heater to increase a temperature of the internal heater during the first phase or to maintain a temperature of the internal heater above ambient temperature during the first phase.
• the method may comprise: during a second phase subsequent to the first phase, controlling a supply of power to the external heater to increase a temperature of the external heater during the second phase.
• the temperature of the internal heater may increase. This may result in the internal heater heating an inner portion of the aerosol-forming substrate to form an aerosol during the first phase.
• the internal heater may heat more aerosol-forming substrate further from the internal heater as heat propagates outwardly from the internal heater.
• the temperature of the internal heater may be increased as the first phase progresses to aid this.
• the temperature of the internal heater may not be increased further, and the temperature of the external heater may increase.
• the external heater heating an outer portion of the aerosol-forming substrate to form an aerosol during the second phase.
• the external heater may heat more aerosol-forming substrate further from the external heater as heat propagates inwardly from the external heater.
• the temperature of the external heater may be increased as the second phase progresses to aid this.
• the inner portion of the aerosol-forming substrate may be significantly depleted during the first phase
• the outer portion of the aerosol-forming substrate may be significantly depleted during the second phase. This may advantageously result in substantially all of the aerosol-forming substrate being depleted so that there is less wasted aerosol-forming substrate, and in a reduction in the risk of overheating and burning the aerosolforming substrate.
• the method may comprise: during a pre-heating phase, controlling a supply of power to one or both of the internal heater and the external heater to increase a temperature of the internal heater to at least an internal heater minimum pre-heating temperature.
• the method may comprise: during a cooling phase subsequent to the pre-heating phase, controlling a supply of power to one or both of the internal heater and the external heater to decrease a temperature of the internal heater to a temperature lower than the internal heater minimum pre-heating temperature.
• the method may comprise: during a first phase subsequent to the cooling phase, controlling a supply of power to one or both of the internal heater and the external heater to increase a temperature of one or both of the internal heater and the external heater.
• the pre-heating phase may reduce a time needed for aerosol generation after a user first activates the system.
• the cooling phase may reduce a risk of a heater overheating, or aerosol-forming substrate burning, or too much aerosol-forming substrate being heated to generate aerosol during the first few puffs of the usage session thereby leaving too little unused aerosol-forming substrate for generating aerosol for later puffs of the usage session.
• the first phase may allow more of the aerosol-forming substrate to be depleted. For example, where the first phase involves one or both of the internal and external heaters gradually increasing in temperature over a plurality of puffs, as the first phase progresses, more of the aerosol-forming substrate may be heated to a sufficient temperature to generate an aerosol.
• these three features may together allow a short time to a first puff without sacrificing user experience towards the end of the usage session because the substrate is already too depleted or the remainder of the substrate is not heated sufficiently to be depleted.
• These three features may also advantageously work together synergistically to allow more consistent aerosol generation from start to finish of a usage session compared with prior art aerosol-generating systems.
• increasing a temperature of the internal heater during the pre-heating phase may allow heating of the substrate sufficiently quickly to allow generation of a substantial quantity of aerosol during an early portion of the usage session.
• decreasing a temperature of the internal heater during the cooling phase may allow sufficient aerosol to be generated whilst preventing the generation of too much aerosol during an intermediate portion of the usage session.
• increasing a temperature of a heater during the first phase may allow sufficient aerosol generation during a later portion of the usage session at a time when much of the aerosol-forming substrate has already been heated to form an aerosol.
• the method comprises, during any phase, controlling a supply of power to the internal heater according to an internal heater power supply profile for that particular phase.
• the method comprises, during any phase, controlling a supply of power to the external heater according to an external heater power supply profile for that particular phase.
• the method may comprise controlling a supply of power to the internal heater according to one or more of: a pre-heating phase internal heater power supply profile during the pre-heating phase; a cooling phase internal heater power supply profile during the cooling phase; a first phase internal heater power supply profile during the first phase; and a second phase internal heater power supply profile during the second phase.
• the method may comprise controlling a supply of power to the external heater according to one or more of: a pre-heating phase external heater power supply profile during the pre-heating phase; a cooling phase external heater power supply profile during the cooling phase; a first phase external heater power supply profile during the first phase; and a second phase external heater power supply profile during the second phase.
• any power supply profile may be different to any other power supply profile.
• the first phase internal heater power supply profile may be different to the second phase internal heater power supply profile.
• the first phase external heater power supply profile may be different to the second phase external heater power supply profile.
• tailoring the heater power supply profiles for the phases may allow tailoring whether any aerosol is formed or the quantity and composition of the aerosol formed during these phases.
• the internal heater may extend from the base of the chamber.
• the internal heater may extend into the chamber, for example towards the open end of the chamber.
• the internal heater may be shaped as a pin, blade, or rod for penetrating an aerosol-forming substrate of an article inserted into the chamber.
• the internal heater may comprise an electrically insulating substrate and an electrically conductive track on the electrically insulating substrate.
• the device may be configured to pass an electrical current through the electrically conductive track in use. This may electrically resistively heat the electrically conductive track.
• the external heater may at least partially surround or define the chamber for receiving the article. Where the external heater is an electrically resistive heater, the external heater may be substantially tubular in shape.
• the external heater may comprise an electrically insulating substrate, for example a substantially tubular electrically insulating substrate, and an electrically conductive track on the electrically insulating substrate.
• the device may be configured to pass an electrical current through the electrically conductive track in use. This may electrically resistively heat the electrically conductive track.
• Suitable electrically insulating materials for example for an electrically insulating substrate of an electrically resistive internal or external heater, may include one or more of: glass, ceramic, anodized metal, coated metal, and Polyimide.
• the ceramic may comprise mica, Alumina or Zirconia.
• Suitable electrically conductive materials may include one or more of: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group.
• semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material.
• Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group.
• suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminiumtitanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetai® and iron-manganese-aluminium based alloys.
• the electrically resistive track may comprise a heating wire or filament, for example a Ni-Cr (Nickel-Chromium), platinum, tungsten or alloy wire or filament.
• the external heater is an electrically resistive heater
• the external heater may comprise or be formed from one or both of a substantially magnetically transparent material and a non-inductively heatable material. This may be particularly advantageous where the system also comprises an inductor, as for the fourth and fifth arrangements described above.
• the external heater may at least partially surround or define the chamber, or may be received in the chamber.
• the inductor may be or comprise a helical inductor coil.
• the inductor may be configured to contact, and thus optionally directly heat, an article received in the chamber.
• the inductor coil may be configured to surround or encircle an article received in the chamber. This may advantageously allow for a concentrated magnetic field around the susceptor and heating around a full circumference of the article by resistive heating of the inductor coil itself.
• the inductor may be or comprise a flat spiral coil, which may also be referred to as a pancake coil.
• a flat spiral coil may spiral in a single plane, for example around a central point.
• a flat spiral coil may be configured to generate an alternating magnetic field within the chamber when supplied with an alternating current and may allow external heating from resistive heating of the inductor itself.
• the flat spiral coil may form, or be located adjacent to and optionally in contact with, a side wall or the base of the chamber.
• the susceptor which may also be referred to as a susceptor element, may comprise or consist of one or more susceptor materials.
• Suitable susceptor materials may include but are not limited to: carbon, carbon-based materials, graphene, graphite, expanded graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminium, nickel, nickel-containing compounds, titanium, and composites of metallic materials.
• Suitable susceptor materials may comprise a ferromagnetic material, for example, ferritic iron, a ferromagnetic alloy, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite.
• a susceptor material may comprise more than 5 percent, preferably more than 20 percent, more preferably more than 50 percent or more than 90 percent of ferromagnetic or paramagnetic materials.
• Preferred susceptor materials may comprise a metal, metal alloy or carbon.
• the method may comprise controlling the supply of power to the external heater according to the first phase external heater power supply profile during the first phase so as to inductively heat the susceptor.
• the method may comprise controlling the supply of power to the external heater according to the second phase external heater power supply profile during the second phase to resistively heat the inductor, for example to resistively heat the inductor more during the second phase than the first phase.
• the inductor is heated, for example resistively heated, to a higher temperature during the second phase than during the first phase.
• a peak temperature of the inductor during the second phase is greater, for example at least 20, 50, or 100 degrees Celsius greater, than a peak temperature of the inductor during the first phase.
• an average temperature of the inductor during the second phase is greater, for example at least 20, 50, or 100 degrees Celsius greater, than an average temperature of the inductor during the first phase.
• greater heating of the external heater during the second phase compared with the first phase may allow an outer portion of the aerosol-forming substrate to be significantly depleted during the second phase. This may result in less waste of the outer portion of the aerosol-forming substrate.
• a temperature of the inductor at an end of the second phase is greater, for example at least 20, 50, or 100 degrees Celsius greater, than a temperature of the inductor at a start of the second phase.
• heating of the external heater more as the second phase progresses may allow the external heater to heat more aerosol-forming substrate further from the external heater as the second phase progresses. This may advantageously allow initial formation of aerosol from an outermost portion of the aerosol-forming substrate, followed by formation of aerosol from gradually more inwardly located portions of the aerosol-forming substrate. This may result in less waste of the outer portion of the aerosol-forming substrate.
• controlling a supply of power to the inductor comprises controlling one or both of a frequency and a magnitude of an alternating current supplied to the inductor.
• the inductive coupling between the inductor and the susceptor may vary with changes in frequency of an alternating current supplied to the inductor.
• the frequency may be adjusted to have a value fsusceptor, associated with an alternating current creating an alternating magnetic field that maximises a transfer of energy to the susceptor, resulting in most of the heat being generated by heating of the susceptor.
• the frequency may also be adjusted to have a value fmductor, associated with an alternating current creating an alternating magnetic field that provides little to no transfer of energy to the susceptor, resulting in all or most of the heat being generated by resistive heating of the inductor.
• the frequency may also be adjusted to have a value f to tai, associated with an alternating current which results in a combination of heating of the susceptor and resistive heating of the inductor.
• Each of these frequencies will vary depending on the materials, physical properties and configuration of the inductor and susceptor, such as the inductance of the inductor coil and magnetic permeability of the material(s) employed for the susceptor.
• the frequency can be adjusted to adjust how much of a power from the power supply is used for resistive heating of the inductor and how much of the power is used for inductive heating of the susceptor.
• controlling the supply of power to the external heater according to the first phase external power supply profile comprises supplying an alternating current at a first frequency to the inductor.
• controlling the supply of power to the external heater according to the second phase external heater power supply profile comprises supplying an alternating current at a second frequency, different to the first frequency, to the inductor.
• controlling a frequency of the current to the inductor may provide an easy way to control heating of the internal heater and the external heater.
• supplying the alternating current at the first frequency to the inductor results in one or both of greater inductive heating of the susceptor and less resistive heating of the inductor, compared with supplying the alternating current at the second frequency to the inductor.
• supplying the alternating current at the second frequency to the inductor results in one or both of greater resistive heating of the inductor and less inductive heating of the susceptor, compared with supplying the alternating current at the first frequency to the inductor.
• this may allow one or both of greater heating of the susceptor during the first phase compared with the second phase, and greater heating of the inductor during the second phase compared with the first phase.
• controlling the supply of power to the external heater according to the second phase external heater power supply profile comprises supplying a direct current, alone or in combination with an alternating current, to the inductor.
• supplying a direct current to the inductor may increase heating of the inductor without significant additional heating of the susceptor.
• no direct current may be supplied to the inductor during the first phase.
• no power is supplied to the external heater during the first phase.
• the external heater is not heated above 100 degrees Celsius during the first phase.
• this may save power whilst the internal heater, which may be part of the device and electrically resistively heated for example, is being used to heat the aerosol-forming substrate to form aerosol during the first phase.
• the method may comprise activating or adjusting a supply of power to one or both of the internal heater and the external heater as a function of one or more of a) a puff count over a usage session; b) time elapsed since commencement of a usage session; and c) detection of a puff in a usage session.
• the device may comprise a heat-conducting element, also referred to herein as a thermally conductive bridging element.
• the thermally conductive bridging element may be positioned between the inductor and the chamber.
• the thermally conductive bridging element may be in contact with the inductor.
• the thermally conductive bridging element may be configured to contact an exterior surface of an article received in the chamber.
• the thermally conductive bridging element may at least partially define the chamber. In use, heat may be transferred from the inductor to the thermally conductive bridging element to the article.
• the thermally conductive bridging element may advantageously allow more uniform heating of the aerosol-forming substrate of the article.
• At least one of the controller which may also be referred to herein as control circuitry, and the thermally conductive bridging element may be configured to prevent inductive coupling between the thermally conductive bridging element and the inductor during use.
• the controller may be configured to provide alternating current with a frequency selected to prevent inductive coupling between the thermally conductive bridging element and the inductor during use.
• the thermally conductive bridging element may be formed from a non-electrically conductive material.
• the thermally conductive bridging element may be formed from a substantially non-inductively heatable material.
• the thermally conductive bridging element may comprise at least one of a polymeric material and a metal.
• the thermally conductive bridging element may comprise at least one of aluminium and a paramagnetic steel.
• the paramagnetic steel may comprise an austenitic steel.
• the power supply may be configured to provide an electric current to the thermally conductive bridging element during use to resistively heat the thermally conductive bridging element.
• the thermally conductive bridging element may then be considered the external heater.
• the external heater or thermally conductive bridging element may comprise a polymeric material and at least one of graphite, a graphite-derived material, and hexagonal boron nitride dispersed within the polymeric material.
• the polymeric material may be referred to as a polymeric matrix.
• the at least one of graphite, a graphite-derived material, and hexagonal boron nitride may be present as filler particles in the polymeric matrix.
• the polymeric material may be or comprise at least one of polyether ether ketone (PEEK) and a liquid crystal polymer (LCP).
• PEEK polyether ether ketone
• LCP liquid crystal polymer
• the external heater or thermally conductive bridging element may comprise the polymeric material in an amount of between 22 percent and 33 percent by weight.
• the graphite-derived material may comprise at least one of expanded graphite and graphite nanoplatelets.
• the external heater or thermally conductive bridging element may comprise the at least one of graphite, a graphite- derived material, and hexagonal boron nitride in an amount of between 62 percent and 69 percent by weight.
• the external heater or thermally conductive bridging element may comprise at least one additive dispersed within the polymeric material.
• the at least one additive may comprise carbon black.
• the external heater or thermally conductive bridging element may comprise the at least one additive in an amount of between 5 percent and 9 percent by weight of the external heater.
• such an external heater or thermally conductive bridging element may be easier to manufacture compared to others.
• thermoplastic properties of the polymeric matrix may allow the composite polymer to be malleable such that it lends itself to precise and controlled shaping. Also, by controlling and adjusting the concentration and distribution of the conductive filler particles dispersed within the polymeric matrix, along with other parameters such as the length and cross-sectional surface area of the external heater, it may be possible to achieve desirable heating properties like resistivity.
• the inductor coil may be suspended inside the chamber.
• this may reduce heat losses from the coil to the housing and improve the efficiency of the device.
• the inductor coil may be a helical coil.
• the helical coil may comprise a first end and a second end.
• the housing may contact the inductor coil only at the first end and the second end of the inductor coil.
• the device may further comprise an airflow channel defined between an inner surface of the housing and an outer surface of the inductor coil.
• the airflow channel may provide fluid communication between the open end of the chamber and the base of the chamber.
• the inductor coil may be formed from a coiled wire.
• the coiled wire may comprise an electrically conductive core and a coating on the electrically conductive core.
• the coating may be electrically insulating.
• the coating may comprise at least one of a polymer, a ceramic, and a glass.
• the inductor coil may comprise a metal.
• the metal may comprise copper.
• the inductor coil may comprise: a first tubular portion of electrically conductive material; a second tubular portion of electrically conductive material; and a helical coil of electrically conductive material extending between the first tubular portion and the second tubular portion.
• the helical coil may be formed integrally with the first tubular portion and the second tubular portion.
• each of the first tubular portion, the second tubular portion, and each turn of the helical coil has a maximum width extending in a direction parallel to a longitudinal axis of the inductor coil, wherein the maximum width of each of the first tubular portion and the second tubular portion is greater than the maximum width of each turn of the helical coil.
• the inductor coil may comprise a plurality of discrete apertures in at least one of the first tubular portion and the second tubular portion.
• the plurality of discrete apertures may be present in both the first tubular portion and the second tubular portion
• the plurality of discrete apertures may be distributed symmetrically in a circumferential direction extending around a longitudinal axis of the inductor coil.
• the inductor coil may further comprise a layer of electrically insulating material extending around an outer surface of the first tubular portion, the second tubular portion and the helical coil.
• the power supply may comprise a first DC power source, optionally in a form of a battery.
• the control circuitry may comprise a DC/AC converter connected to the first DC power source.
• the system for example device or control circuitry, may comprise power supply electronics, which may be configured to operate at high frequency.
• the term “high frequency” may be understood to denote a frequency ranging from 1 to 30, or 1 to 10, or 5 to 7 Megahertz.
• the power supply electronics may comprise the DC/AC converter connected to the first DC power source.
• the DC/AC converter may comprise a Class-E power amplifier including a first transistor switch and an LC load network.
• Class-E power amplifiers are generally known and are described in detail, for example, in the article “Class-E RF Power Amplifiers”, Nathan O. Sokal, published in the bimonthly magazine QEX, edition January/February 2001 , pages 9-20, of the American Radio Relay League (ARRL), Newington, CT, U.S.A..
• the LC load network may comprise a shunt capacitor and a series connection of a capacitor and the inductor coil.
• the power supply electronics preferably includes a second DC power source connected to the LC load network at a position between the capacitor and the inductor coil for supplying DC current to the inductor coil.
• the second DC power source may be the same power source as the first DC power source. For example, they may be the same battery.
• the power supply electronics may include a choke inductor between the second DC power source and the capacitor.
• the choke inductor preferably has a higher inductance value than the inductor coil.
• the power supply electronics may also include a choke inductor between the first DC power source and the capacitor.
• the power supply electronics may include a second switch between the second DC power source and the inductor coil.
• the second switch may be a second transistor switch.
• the power supply electronics may include second capacitor connected in parallel with the inductor coil. This may reduce a difference between fsusceptor and finductor-
• the method comprises a pre-heating phase.
• the pre-heating phase may be part of the first phase, or may end prior to the first phase beginning. Where the pre-heating phase is part of the first phase, the pre-heating phase may begin at the start of the first phase. Where the pre-heating phase is part of the first phase, the pre-heating phase may end before the first phase has finished, for example before half of a total length of time of the first phase has lapsed.
• the method comprises, during the pre-heating phase, controlling a supply of power to the internal heater according to a pre-heating phase internal heater power supply profile.
• the method comprises, during the pre-heating phase, controlling a supply of power to the external heater according to a pre-heating phase external heater power supply profile.
• the pre-heating phase internal heater power supply profile is different to one or both of the first phase internal heater power supply profile and the second phase internal heater power supply profile.
• the pre-heating phase external heater power supply profile is different to one or both of the first phase external heater power supply profile and the second phase external heater power supply profile.
• a pre-heating phase may allow the system to quickly prepare for aerosol formation.
• substantially no aerosol is formed during the pre-heating phase.
• this may allow more aerosol to be formed in the first and second phases.
• the internal heater is heated to at least an internal heater minimum pre-heating temperature.
• the external heater is heated to at least an external heater minimum pre-heating temperature.
• the internal heater minimum pre-heating temperature may be greater than the external heater minimum pre-heating temperature.
• the internal heater is heated to a higher temperature than the external heater. This may be advantageous where the internal heater is mostly responsible for heating the aerosol-forming substrate to form an aerosol in the first phase.
• a power supplied to the internal heater during the pre-heating phase is greater than or equal to one or both of: a power supplied to the internal heater during the first phase; and a power supplied to the internal heater during the second phase.
• a peak temperature reached by the internal heater during the pre-heating phase is greater than or equal to one or both of: a peak temperature reached by the internal heater during the first phase; and a peak temperature reached by the internal heater during the second phase.
• this may allow quick formation of aerosol during the first phase and thus reduce a minimum time needed for the system to first generate an aerosol.
• the internal heater is heated but the external heater is not substantially heated.
• the external heater may not be heated to more than 100 degrees Celsius.
• no power is supplied to the external heater.
• this may save power, particularly where there is no need for the external heater to reach a high temperature until the second phase.
• a temperature of the internal heater for at least a portion of the pre-heating phase is one or more of: at least 100, 200, or 300 degrees Celsius; and no more than 500 or 400 degrees Celsius.
• a temperature of the internal heater for at least a portion of the pre-heating phase is between 200 and 500, or between 200 and 400, or between 300 and 400, preferably around 350 degrees Celsius.
• a temperature of the external heater for at least a portion of the pre-heating phase, for example the external heater minimum pre-heating temperature is one or more of: at least 100 or 200 degrees Celsius; and no more than 500 or 400 or 300 degrees Celsius.
• a temperature of the external heater for at least a portion of the pre-heating phase is between 100 and 500, or between 100 and 400, or between 100 and 300, or between 200 and 500, or between 200 and 400, or between 200 and 300, preferably around 240 degrees Celsius.
• such temperatures may provide an optimal compromise between quick initial heating and a risk of burning aerosol-forming substrate.
• a temperature of the external heater is, for at least a portion of one or two or all of the pre-heating phase and the first phase and the second phase, at least 210 degrees Celsius.
• the pre-heating phase lasts for at least 5, 10, 20, or 30 seconds.
• the pre-heating phase lasts for no more than 60, 45, or 30 seconds.
• the pre-heating phase lasts for between 5 and 60, or between 5 and 45 seconds.
• this may allow sufficient pre-heating of the internal heater without taking so long as to frustrate a user.
• the method comprises a cooling phase.
• the cooling phase is subsequent to, for example immediately subsequent to, the pre-heating phase.
• the first phase may be subsequent to, for example immediately subsequent to, the cooling phase.
• a temperature of the internal heater decreases, for example from at least the internal heater minimum pre-heating temperature.
• a temperature of the internal heater decreases by at least 10, 20, 50 or 100 degrees Celsius.
• a temperature of the internal heater decreases to a temperature less than 300 or 250 degrees Celsius.
• a temperature of the internal heater decreases to a temperature of at least 150 or 200 degrees Celsius.
• a temperature of the external heater decreases, for example from at least the external heater minimum pre-heating temperature.
• a temperature of the external heater decreases by at least 10, 20, 50 or 100 degrees Celsius.
• a temperature of the external heater decreases to a temperature less than 300 or 250 degrees Celsius.
• a temperature of the external heater decreases to a temperature of at least 100, 150 or 200 degrees Celsius.
• a fall in temperature of the internal heater over the cooling phase may be greater than a fall in temperature of the external heater over the cooling phase. This may be at least partly because the internal heater may be at a higher temperature than the external heater at one or both of the end of the pre-heating phase and the start of the cooling phase.
• the cooling phase may reduce a risk of a heater overheating, or aerosolforming substrate burning, or too much aerosol-forming substrate being heated to generate aerosol during the first few puffs of the usage session thereby leaving too little unused aerosolforming substrate for generating aerosol for later puffs of the usage session.
• no power is supplied to the internal heater.
• no power is supplied to the external heater.
• this may allow the fastest rate of cooling and thus ensure that the early puffs do not deplete too much aerosol.
• the cooling phase lasts for at least 60, 90, 120, 150, or 180 seconds.
• the cooling phase lasts for no more than 360, 300, 270, or 240 seconds.
• the cooling phase lasts for between 60 and 360, or between 60 and 300, or between 90 and 270 seconds.
• the cooling phase lasts for a duration of at least one puff, optionally at least 2, 3, or 5 puffs.
• the cooling phase lasts for no more than 10 or 8 or 6 puffs.
• the cooling phase lasts for between 1 and 10, or between 1 and 8, or between 2 and 8, or between 2 and 8, or between 2 and 6 puffs.
• such lengths of time may allow optimal cooling of one or both of the internal heater and the external heater.
• one or both of the first phase and the second phase is an aerosol-generating phase.
• the first phase immediately follows the pre-heating phase.
• the second phase immediately follows the first phase.
• an average or peak temperature of the internal heater across the first phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than an average temperature of the external heater across the first phase.
• the internal heater is heated but the external heater is not substantially heated.
• the external heater may not be heated to greater than 100 degrees Celsius.
• no power is supplied to the external heater during the first phase.
• a temperature of the internal heater is, for at least a portion of the first phase, sufficiently high to form an aerosol from the aerosol-forming substrate.
• a temperature of the internal heater is, for at least a portion of the first phase, at least 150, 200, 250, or 300 degrees Celsius.
• a temperature of the internal heater is, for at least a portion of the first phase, no more than 500, 450, or 400 degrees Celsius.
• a temperature of the internal heater is, for at least a portion of the first phase, between 150 and 500, or between 200 and 450, or between 250 and 400 degrees Celsius.
• a temperature of the external heater is, for at least a portion of the first phase, at least 50, 100, 150, 200, 250, or 300 degrees Celsius.
• a temperature of the external heater is, for at least a portion of the first phase, no more than 500, 400, 300 or 200 degrees Celsius.
• a temperature of the external heater is, for at least a portion of the first phase, between 50 and 500, or between 50 and 400, or between 50 and 30, or between 50 and 200 degrees Celsius.
• this may allow production of a desired quantity and composition of aerosol.
• one or both of the first phase and the second phase lasts for at least 60, 90, 120, 150, or 180 seconds.
• one or both of the first phase and the second phase lasts for no more than 360, 300, 270, or 240 seconds.
• one or both of the first phase and the second phase lasts for between 60 and 360, or between 60 and 300, or between 90 and 270 seconds.
• one or both of the first phase and the second phase lasts for a duration of at least one puff, optionally at least 2, 3, or 5 puffs.
• one or both of the first phase and the second phase lasts for no more than 10 or 8 puffs.
• one or both of the first phase and the second phase lasts for between 1 and 10, or between 1 and 8, or between 2 and 8, or between 3 and 8 puffs.
• such lengths of time may allow significant depletion of the aerosolforming substrate.
• a temperature of one or both of the internal heater and the external heater is held constant or increases during the first phase.
• a temperature of one or both of the internal heater and the external heater at an end of the first phase is greater than its temperature at a start of the first phase.
• an average temperature of one or both of the internal heater and the external heater over a first portion, for example first half, of the first phase is greater than, less than or equal to its average temperature over a subsequent second portion, for example subsequent second half, of the first phase.
• a temperature of one or both of the internal heater and the external heater increases monotonically, for example continuously, for at least a portion of the first phase.
• increasing a temperature of a heater as the first phase progresses may allow the heater to heat more of the aerosol-forming substrate further from the heater sufficiently to form an aerosol as the first phase progresses. This may reduce an amount of wasted, or unused, aerosol-forming substrate.
• an average temperature of the external heater over a first portion of the first phase may be greater than or equal to an average temperature of the external heater over a subsequent second portion of the first phase. This may be because, in certain embodiments, there may be no need to increase a temperature of the external heater as the first phase progresses, and it is therefore more energy efficient not to increase the temperature of the external heater at this stage. For example, where the temperature of the internal heater is not decreased as the first phase progresses, this may allow the internal heater to generate an aerosol from more outward parts of the inner portion of the substrate as the first phase progresses. Thus, at this stage, there may be no need for the external heater to be heated to heat an outer portion of the substrate to generate an aerosol. This can be saved for the second phase, where present. This may allow the method to be energy efficient and provide consistent amounts of aerosol across the entire usage session.
• an average temperature of the internal heater over a first portion of the first phase to be between 150 and 300 degrees Celsius; • an average temperature of the internal heater over a subsequent second portion of the first phase to be greater than the average temperature of the internal heater over the first portion of the first phase, and to preferably be between 200 and 400 degrees Celsius, more preferably between 250 and 350 degrees Celsius;
• an average temperature of the external heater over the second portion of the first phase to be equal to or less than the average temperature of the external heater over the first portion of the first phase, and to preferably be between 150 and 250 degrees Celsius;
• an average temperature of the external heater over the first portion of the first phase to be less than the average temperature of the internal heater over the first portion of the first phase, and to preferably be between 150 and 250 degrees Celsius;
• an average temperature of the external heater over the second portion of the first phase to be less than the average temperature of the internal heater over the second portion of the first phase, and to preferably be between 150 and 250 degrees Celsius.
• a temperature of the external heater is held constant, for example at a temperature of one or more of: at least 150, 200, 250, or 300 degrees Celsius; and no more than 350, or 300 degrees Celsius.
• a temperature of the external heater is held constant, for example at a temperature of between 100 and 350, or between 150 and 300, or between 200 and 300 degrees Celsius.
• a temperature of the internal heater is increased, for example by at least 10, 20, 50 or 100 degrees Celsius, or to at least 200, 250, or 300 degrees Celsius, or both.
• holding the temperature of the external heater constant and increasing the temperature of the internal heater may allow optimal depletion of the substrate during later puffs. This may be particularly advantageous where there is no second phase after the first phase.
• a temperature of the internal heater is held at a first phase first internal heater temperature for at least a portion, for example a first portion, of the first phase.
• a temperature of the internal heater is held at a first phase second internal heater temperature, different to the first phase first internal heater temperature, for a second portion, subsequent to the first portion, of the first phase.
• a temperature of the internal heater is held at a first phase third internal heater temperature, different to one or both of the first phase first internal heater temperature and the first phase second internal heater temperature, for a third portion, subsequent to the second portion, of the first phase.
• the first phase second internal heater temperature is greater, for example at least 5, 10, 20, 30, or 50 degrees Celsius greater, than the first phase first internal heater temperature.
• the first phase third internal heater temperature is greater, for example at least 5, 10, 20, 30, or 50 degrees Celsius greater, than the one or both of the first phase first internal heater temperature and the first phase second internal heater temperature.
• holding a temperature of the internal heater at sequentially higher temperatures as the first phase progresses may allow the internal heater to heat more of the aerosol-forming substrate further from the internal heater sufficiently to form an aerosol as the first phase progresses.
• a temperature of the external heater is held at a first phase first external heater temperature for at least a portion of the first phase.
• a temperature of the external heater is held at a first phase first external heater temperature for a first portion of the first phase.
• a temperature of the external heater is held at a first phase second external heater temperature, different to the first phase first external heater temperature, for a second portion, subsequent to the first portion, of the first phase.
• a temperature of the external heater is held at a first phase third external heater temperature, different to one or both of the first phase first external heater temperature and the first phase second external heater temperature, for a third portion, subsequent to the second portion, of the first phase.
• the first phase second external heater temperature is greater, for example at least 5, 10, 20, 30, or 50 degrees Celsius greater, than the first phase first external heater temperature.
• the first phase third external heater temperature is greater, for example at least 5, 10, 20, 30, or 50 degrees Celsius greater, than the one or both of the first phase first external heater temperature and the first phase second external heater temperature.
• holding a temperature of the external heater at sequentially higher temperatures as the first phase progresses may prepare the external heater for the second phase, where the second heater may be more critical in heating the substrate to form an aerosol than the internal heater.
• holding a temperature of the external heater at sequentially higher temperatures as the first phase progresses may also allow the external heater to heat more of the aerosol-forming substrate further from the external heater sufficiently to form an aerosol as the first phase progresses.
• the external heater is heated during the second phase but the internal heater is not substantially heated during the second phase.
• no power is supplied to the internal heater during the second phase.
• little or no heating of the internal heater during the second phase may save power without compromising aerosol production since the internal heater may already be hot when the second phase begins and since, during the second phase, the external heater may be predominantly or solely responsible for heating the outer portion of the aerosol-forming substrate to form an aerosol.
• an average or peak temperature of the internal heater across the second phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than an average temperature of the external heater across the second phase.
• the external heater may be mostly responsible for heating the outer portion of the substrate to form an aerosol, it may not be necessary for the external heater to be heated to as high temperature as the internal heater since the aerosol-forming substrate may already be warm when the second phase begins.
• a temperature of one or both of the internal heater and the external heater is, for at least a portion of the second phase, at least 150, 200, 250, or 300 degrees Celsius.
• a temperature of one or both of the internal heater and the external heater is, for at least a portion of the second phase, no more than 500, 450, or 400 degrees Celsius.
• a temperature of one or both of the internal heater and the external heater is, for at least a portion of the second phase, between 150 and 500, or between 200 and 450, or between 250 and 400 degrees Celsius.
• these temperatures may allow production of a desired quantity and composition of aerosol. This may particularly allow the external heater, or the internal heater and external heater together, to heat an outer portion of the aerosol-forming substrate to a sufficiently high temperature to produce a desired quantity and composition of aerosol.
• a temperature of one or both of the internal heater and the external heater may be at least 200, 250, 300, or 350 degrees Celsius at the end of the second phase.
• a temperature of the external heater at an end of the second phase is one or both: cooler than 20, 50 or 100 degrees Celsius above; and hotter than 20, 50 or 100 degrees Celsius above, a temperature of the internal heater at the end of the second phase.
• heating of the aerosolforming substrate may be maximised without too high of a risk of overheating or burning if the internal heater and the external heater reach a similar temperature at the end of the second phase, for example a temperature not far below the temperature at which there is a risk of overheating or burning.
• a temperature of the external heater at an end of the second phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than a temperature of the external heater at a start of the second phase.
• a temperature of the external heater at an end of the second phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than a temperature of the external heater at a start of the second phase.
• more of the aerosol-forming substrate further from the external heater may be heated to a sufficiently high temperature to form an aerosol as the second phase progresses.
• a temperature of the internal heater is held constant, or decreases, for example monotonically or continuously decreases, for at least a portion of the second phase.
• an average temperature of the internal heater over a first portion, for example first half, of the second phase is greater than or equal to an average temperature of the internal heater over a subsequent second portion, for example subsequent second half, of the second phase. It may not be necessary to increase a temperature of the internal heater over the second phase since, during the second phase, the external heater may be predominantly or solely responsible for heating aerosol-forming substrate to form an aerosol.
• a temperature of the external heater is held constant or increases during the second phase.
• a temperature of the external heater an end of the second phase is greater than a temperature of the external heater at a start of the second phase.
• an average temperature of the external heater over a first portion, for example first half, of the second phase is less than, greater than or equal to an average temperature of the external heater over a subsequent second portion, for example subsequent second half, of the second phase.
• a temperature of the external heater increases substantially monotonically, for example continuously, for at least a portion of the second phase.
• increasing a temperature of the external heater as the second phase progresses may allow the external heater to gradually heat more of the aerosol-forming substrate further from the external heater sufficiently to form an aerosol as the second phase progresses.
• a temperature of the external heater is held at a second phase first external heater temperature for at least a portion of the second phase.
• a temperature of the external heater is held at a second phase first external heater temperature for a first portion of the second phase.
• a temperature of the external heater is held at a second phase second external heater temperature, different to the second phase first external heater temperature, for a second portion, subsequent to the first portion, of the second phase.
• a temperature of the external heater is held at a second phase third external heater temperature, different to one or both of the second phase first external heater temperature and the second phase second external heater temperature, for a third portion, subsequent to the second portion, of the second phase.
• the second phase second external heater temperature is greater, for example at least 20, 50 or 100 degrees Celsius greater, than the second phase first external heater temperature.
• the second phase third external heater temperature is greater, for example at least 20, 50 or 100 degrees Celsius greater, than the one or both of the second phase first external heater temperature and the second phase second external heater temperature.
• holding a temperature of the external heater at sequentially higher temperatures as the second phase progresses may allow the external heater to heat more of the aerosolforming substrate further from the external heater sufficiently to form an aerosol as the second phase progresses. This may reduce an amount of wasted, or unused, aerosol-forming substrate in the outer portion of the aerosol-forming substrate.
• first phase internal heater power supply profile is different to the second phase internal heater power supply profile.
• first phase external heater power supply profile is different to the second phase external heater power supply profile.
• tailoring the power supply profiles can allow tailoring of aerosol formation. For example, such tailoring may allow significant depletion of an inner portion of the substrate during the first phase followed by significant depletion of an outer portion of the substrate during the second phase.
• an average or peak temperature of the external heater during the second phase is greater than, for example at least 20, 50 or 100 degrees Celsius greater than, an average temperature of the external heater during the first phase.
• an average temperature difference between the internal heater and the external heater during the first phase is greater than, for example at least 20, 50 or 100 degrees Celsius greater than, an average temperature difference between the internal heater and the external heater during the second phase.
• such heating of the external heater during the second phase may allow the external heater to heat the outer portion of the substrate to form an aerosol during the second phase. This may prevent wasting the outer portion of the substrate.
• an average temperature difference between the internal heater and the external heater at a start of the second phase is greater than 20, 50 or 100 degrees Celsius.
• an average temperature difference between the internal heater and the external heater at an end of the second phase is less than 20, 50 or 100 degrees Celsius.
• the outer portion of the substrate may be heated sufficiently to form an aerosol.
• the internal heater may still contribute to heating of the substrate during the second phase. However, this contribution may have a smaller influence on aerosol formation compared with the external heater during the second phase and the internal heater during the first phase.
• initiation of the second phase is triggered by: a predetermined number of puffs on the aerosol-forming substrate being taken during a current usage session, for example two, three, four, or five puffs on the aerosol-forming substrate being taken during a current usage session; or a predetermined time from a first puff on the aerosol-forming substrate passing; or a predetermined time from an activation, for example a first activation, of the internal heater or the external heater passing; or a predetermined time from an the internal heater or the external heater reaching a predetermined temperature passing; or a predetermined time from beginning the preheating phase, ending the pre-heating phase, or beginning the first phase passing; or activation of a user-activatable trigger; or a combination of any one or more of these options.
• initiation of the second phase may be triggered as soon as a user-activatable trigger is activated and a predetermined time from beginning the first phase has passed.
• initiating the second phase after such a trigger point may allow the first phase to have a sufficient length of time to form aerosol from a majority of an inner portion of the substrate, whilst still allowing a sufficient length of time for a typical aerosol-generating experience to form aerosol from a majority of an outer portion of the substrate during the second phase.
• the method may comprise supplying power from the at least one power supply to at most one of the internal heater and the external heater at all times.
• the method may comprise heating at most one of the internal heater and the external heater at all times.
• the method may comprise never supplying power to, or never heating, both the internal heater and the external heater simultaneously.
• the method may comprise alternating, for example multiple times per second, between supplying power to, or heating, the internal heater and supplying power to, or heating, the external heater. This may advantageously reduce the maximum amount of power the battery must be able to supply. Alternatively, or in addition, this may advantageously simplify the control of the supplies of power to the internal and external heater.
• the external heater could be an inductor and the internal heater could be a susceptor.
• power could be supplied to the external heater to inductively heat the internal heater. This power could result in a very small increase in temperature, for example less than 15 degrees Celsius, of the external heater. But, in this context, this would not be considered heating the internal heater.
• the method may comprise, at a beginning of the pre-heating phase, heating the internal heater to a temperature above 100 or 150 degrees Celsius before the external heater is heated to a temperature of at least 50 or 90 degrees Celsius.
• the method may comprise, after heating the internal heater to a temperature above 100 or 150 degrees Celsius, alternating, for example multiple times per second, between heating the internal heater and the external heater or alternating between supplying power to the internal heater and the external heater, for example to attain or maintain temperatures of the internal heater and the external heater at, or near to, their respective target temperatures, for example during any one or more or all of: the rest of the pre-heating phase, the cooling phase, the first phase and the second phase.
• the method may prioritise the internal heater over the external heater. This may be advantageous because, for quick generation of an aerosol after activation, it may be more important for the internal heater to reach a high temperature quickly than for the external heater to reach a high temperature quickly.
• the first preferred method is a method of controlling an aerosol-generating system, the aerosol-generating system comprising: an internal heater configured to heat an aerosol-forming substrate from within the aerosol-forming substrate; and an external heater configured to heat the aerosol-forming substrate from outside the aerosolforming substrate.
• the first preferred method comprises: during a first phase, for example for an entirety of the first phase, heating the internal heater to or maintaining the internal heater at a temperature above a first predetermined temperature; during the first phase, for example for an entirety of the first phase, heating the external heater to or maintaining the external heater at a temperature below the first predetermined temperature; and during a second phase subsequent to the first phase, heating the external heater to a temperature above the first predetermined temperature.
• the internal heater may allow quick generation of an aerosol towards a start of the session and may heat an inner portion of the substrate to release an aerosol during the first few puffs. Then, the external heater may be used to heat an outer portion of the substrate to release an aerosol during later puffs. This may advantageously reduce how much of the substrate is wasted.
• heating the internal heater may be achieved by controlling the power supplied to one or both of the internal heater and the external heater.
• Heating the external heater may be achieved by controlling the power supplied to the external heater.
• heating the internal heater to or maintaining the internal heater at a temperature above a first predetermined temperature may occur simultaneously with heating the external heater to or maintaining the external heater at a temperature below the first predetermined temperature.
• the first preferred method may comprise a pre-heating phase.
• the pre-heating phase may occur before the first phase.
• Features described herein in relation to a pre-heating phase may apply to the pre-heating phase of the first preferred method.
• the first preferred method may comprise a cooling phase.
• the cooling phase may occur after, for example immediately after, the pre-heating phase.
• the cooling phase may occur before, for example immediately before, the first phase.
• Features described herein in relation to a cooling phase may apply to the cooling phase of the first preferred method.
• one or both of the internal heater and the external heater may reduce in temperature by at least 30 or 40 degrees Celsius in under 10 or 15 seconds.
• the first predetermined temperature may be 100 or 150 degrees Celsius.
• features described herein in relation to first and second phases herein may apply to the first and second phases of the first preferred method. Nonetheless, some particularly preferable features for the first and second phases are set out below.
• the first preferred method may comprise, during the first phase, for example for an entirety of the first phase, heating the internal heater to or maintaining the internal heater at a temperature above 100 or 150 degrees Celsius.
• the first preferred method may comprise, during the first phase, for example for an entirety of the first phase, heating the internal heater to or maintaining the internal heater at a temperature below 400 or 300 degrees Celsius.
• the temperature of the internal heater during the first phase may not exceed 300 or 400 degrees Celsius.
• the first preferred method may comprise, during the first phase, for example for an entirety of the first phase, heating the internal heater to or maintaining the internal heater at a temperature between 100 and 400 or between 150 and 300 degrees Celsius.
• the first preferred method may comprise, during the first phase, for example for an entirety of the first phase, heating the external heater to or maintaining the external heater at a temperature below 150 or 100 degrees Celsius.
• the temperature of the external heater during the first phase may not exceed 100 or 150 degrees Celsius.
• the first preferred method may comprise, during the first phase, for example for an entirety of the first phase, heating the external heater to or maintaining the external heater at a temperature above 30 or 50 degrees Celsius.
• the first preferred method may comprise, during the first phase, for example for an entirety of the first phase, heating the external heater to or maintaining the external heater at a temperature between 30 and 150 or between 50 and 100 degrees Celsius.
• the second phase of the first preferred method or the method according to the first aspect may occur after, for example immediately after, the first phase. Initiation of the second phase may be triggered by detecting that a predetermined number of puffs on the system has been taken during a current usage session, for example detecting that three, four, five, or six puffs on the system have been taken during the current usage session. This may be the point at which it starts to become difficult to generate sufficient aerosol from an inner portion of the substrate using the internal heater without increasing a temperature of the internal heater so much as to risk burning the substrate. So it may be particularly beneficial to initiate the second phase at this stage.
• the first preferred method may comprise, during the second phase, for example for an entirety of the second phase, maintaining a temperature of the internal heater above the first predetermined temperature.
• the first preferred method may comprise, during the second phase, for example for an entirety of the second phase, maintaining a temperature of the internal heater above 100 or 150 degrees Celsius.
• the first preferred method may comprise, during the second phase, for example for an entirety of the second phase, maintaining a temperature of the internal heater below 400 or 300 degrees Celsius.
• the temperature of the internal heater during the second phase may not exceed 300 or 400 degrees Celsius.
• the first preferred method may comprise, during the second phase, for example for an entirety of the second phase, maintaining a temperature of the internal heater between 100 and 400 or between 150 and 300 degrees Celsius.
• the first preferred method may comprise, during the second phase, heating the external heater to a temperature greater than the first predetermined temperature or 100 or 150 degrees Celsius.
• the first preferred method may comprise, during the second phase, after heating the external heater to a temperature greater than the first predetermined temperature or 100 or 150 degrees Celsius, maintaining the external heater at a temperature greater than the first predetermined temperature or 100 or 150 degrees Celsius for the rest of the second phase.
• the first preferred method may comprise, during the second phase, heating the external heater to a temperature no more than 300 or 400 degrees Celsius.
• the temperature of the external heater during the second phase may not exceed 300 or 400 degrees Celsius.
• the first preferred method may comprise, during the second phase, heating the external heater to between 100 and 400 or between 150 and 300 degrees Celsius.
• the first preferred method may comprise, during the second phase, after heating the external heater to a temperature between 100 and 400 or between 150 and 300 degrees Celsius, maintaining the external heater at a temperature between 100 and 400 or between 150 and 300 degrees Celsius for the rest of the second phase. Additional features described earlier in relation to how long the first and second phases may last may equally apply to the first preferred method.
• the second phase of the first preferred method or method according to the first aspect may comprise two, three, four or five consecutive portions. Each portion may have the same length in time, or may last for the same number of detected puffs on the system.
• the average temperature of the external heater across each portion, other than the first portion may be greater, for example at least 10, 20 or 30 degrees Celsius greater, than the immediately preceding portion.
• the second phase may comprise three consecutive portions.
• the three consecutive portions may have the same length in time, or may last for the same number of detected puffs on the system.
• the average temperature of the external heater across the first portion may be between 30 and 150 degrees Celsius
• the average temperature of the external heater across the second portion, occurring immediately after the first portion may be between 80 and 200 degrees Celsius
• the average temperature of the external heater across the third portion, occurring immediately after the second portion may be between 150 and 400 degrees Celsius.
• the inventors have found that these temperature ranges may be surprisingly good because, during the first portion, the external heater may mostly reduce a cooling effect of airflow on the internal heater to help the internal heater produce aerosol from an inner portion of the substate.
• these three portions may advantageously allow consistent production of quality aerosol across a usage session whilst minimising a risk of burning the substrate due to a heater being heated to too high of a temperature and also minimising waste of the substrate by heating both inner and outer portions of the substrate significantly.
• the first preferred method or method according to the first aspect may comprise, during the second phase, for example for most or for an entirety of the second phase, increasing a temperature or target temperature of the external heater: monotonically or continuously; or monotonically or continuously until a maximum allowed external heater temperature or target temperature is reached.
• the first preferred method or method according to the first aspect may comprise, during the second phase, increasing a temperature or target temperature of the external heater in response to detection of at least one puff, for example in response to detection of at least one particular puff such as the fourth puff detected during the second phase or the current usage session.
• the method may comprise, during the second phase, increasing a temperature or target temperature of the external heater in response to detection of a first predetermined number of puffs, for example a first predetermined number of puffs during the current usage session or during the second phase.
• the method may comprise increasing a temperature or target temperature of the external heater again in response to detection of a second predetermined number of puffs, for example a second predetermined number of puffs during the current usage session or during the second phase.
• the method may comprise, during the second phase, for example for a portion or an entirety of the second phase, increasing a temperature or target temperature of the external heater in response to each puff detected during the second phase, or in response to each puff detected during the second phase until a maximum allowed external heater temperature or target temperature is reached.
• the second phase may last for one or both of at least 60, 90, 120, 150, or 180 seconds and a duration of at least 2, 3, or 5 puffs on the system.
• the first preferred method or method according to the first aspect may comprise, during a first portion of the second phase, in response to detecting a predetermined number of puffs, for example three, four, five or six puffs, on the system during the second phase or the current usage session, increasing a temperature or target temperature of the external heater, for example to a temperature between 60 and 160, preferably between 80 and 130, more preferably between 100 and 125 degrees Celsius.
• the first portion of the second phase may begin at the beginning of the second phase.
• the first portion of the second phase may last for at least a second predetermined number of puffs, for example at least two, three or four puffs, on the system during the current usage session.
• the temperature of the external heater may not necessarily be raised sufficiently high so as to generate a substantial amount of aerosol from an outer portion of the substrate.
• the heating of the external heater may mean that the inner portion of the substrate, which may be heated predominantly by the internal heater to form an aerosol, is not cooled as much by cool air passing through the substrate as a user puffs on the system.
• the heating of the external heater may advantageously help to keep the inner portion of the substrate at a suitably high temperature during puffs.
• the first preferred method or method according to the first aspect may comprise, during a second portion of the second phase, in response to detecting a third predetermined number of puffs, for example six, seven, eight, nine, or ten puffs, on the system during the second phase or the current usage session, increasing a temperature or target temperature of the external heater, for example to a temperature between 130 and 400, preferably between 160 and 300, more preferably between 180 and 250, degrees Celsius.
• the second portion of the second phase may begin after, for example immediately after, the first portion of the second phase.
• the second portion of the second phase may last for at least a fourth predetermined number of puffs, for example at least two, three or four puffs, on the system during the current usage session.
• the temperature of the external heater may be raised sufficiently high so as to generate an aerosol from the outer portion of the substrate.
• the inventors have found that the particular temperature ranges set out in the above paragraphs, when initiated in response to the number of puffs as set out in the above paragraphs, may advantageously allow the provision of a consistent, high-quality aerosol over the course of a typical usage session.
• the temperature of the external heater may be less than the temperature of the internal heater for at least part, for example a beginning part, of the first portion or an initial portion of the second phase.
• the temperature of the external heater may be greater than the temperature of the internal heater for at least part, for example a final part, of the second portion or a final portion of the second phase.
• the method may comprise increasing a supply of power to one or both of the internal heater and the external heater in response to a or each puff. This may compensate for a cooling effect resulting from the or each puff.
• the first preferred method may comprise, during the preheating phase, one or both of: heating the internal heater to at least an internal heater minimum pre-heating temperature; and heating the external heater to at least an external heater minimum pre-heating temperature.
• the internal heater minimum pre-heating temperatures and external heater minimum pre-heating temperatures described earlier apply equally here.
• the system may be configured to determine or estimate a temperature of one or more or all of the internal heater, the external heater, a heating zone within the chamber, and the aerosol-forming substrate.
• determining a temperature of a component may refer to determining a temperature at one or more locations of the component.
• the system for example the device, may comprise a temperature-sensing means for this purpose.
• the temperature-sensing means may be or comprise one or more dedicated temperature sensors.
• the controller may be configured to determine a temperature of a heater, for example a resistive heater, by measuring or calculating its electrical resistance. In this case, the controller may be considered to comprise the temperature-sensing means.
• the system may comprise an air inlet.
• the system for example the article or a mouthpiece of the device, may comprise an air outlet.
• the system for example the article, may comprise an air flow path. The air flow path may connect the air inlet and the air outlet. In use, for example in response to a puff on the article or any mouthpiece of the system, air may flow through the air inlet and then through the article and then through the air outlet. After flowing through the air outlet, the air may flow into a mouth of a user.
• the article may comprise, or be in the form of, a cartridge.
• the article may appear substantially similar to a conventional cigarette.
• the article may be substantially cylindrical, for example right cylindrical, in shape.
• the article may have a length of between 30 mm and 120 mm, for example between 40 mm and 80 mm, for example about 45 mm.
• the article may have a diameter of between 3.5 mm and 10 mm, for example between 4 mm and 8.5 mm, for example between 4.5 mm and 7.5 mm.
• the substrate may be substantially cylindrical, for example right cylindrical, in shape. References herein have been made to an inner portion and an outer portion of the aerosol-forming substrate.
• the inner portion may be or comprise aerosol-forming material in an axially central portion, for example axially central cylindrical portion or axially central right cylindrical portion, of the aerosol-forming substrate.
• the outer portion may be or comprise aerosol-forming material in an axially outer portion of the aerosol-forming substrate.
• the outer portion may be cylindrical, for example right cylindrical in shape.
• the outer portion may have an annular, for example circular annular, cross-section. There may be no aerosol-forming substrate between the inner and outer portions.
• the inner portion and outer portion may be in contact. An entirety of the aerosol-forming material of the aerosol-forming substrate may be found in the inner and outer portions.
• the article comprises a front plug.
• the article comprises an aerosolforming substrate.
• the article comprises a first hollow tube, for example a first hollow acetate tube.
• the article comprises a second hollow tube, for example a second hollow acetate tube.
• the second hollow tube comprises one or more ventilation holes.
• the article comprises a mouth plug filter.
• the article comprises wrapper, for example a paper wrapper.
• one or more or all of the front plug, the aerosol-forming substrate, the first hollow tube, the second hollow tube where present, and the mouth plug filter are circumscribed by the wrapper.
• the front plug is arranged a most upstream end of the article.
• the aerosol-forming substrate is arranged downstream of the front plug.
• the first hollow tube is arranged downstream of the aerosol-forming substrate.
• the second hollow tube is arranged downstream of the first hollow tube.
• the mouth plug filter is arranged downstream of one or both of the first hollow tube and the second hollow tube.
• the mouth plug filter is arranged at a most downstream end of the article.
• the most downstream end of the article which may be referred to as a mouth end of the article, may be configured for insertion into a mouth of a user. A user may be able to inhale on, for example directly on, the mouth end of the article.
• One or more of the front plug, the aerosol-forming substrate, the first hollow tube, the second hollow tube, and the mouth plug filter may be substantially cylindrical, for example right cylindrical, in shape.
• One or more of the front plug, the aerosol-forming substrate, the first hollow tube, the second hollow tube, and the mouth plug filter may have a diameter of between 3.5 mm and 10 millimetres.
• the front plug has a length of between 2 and 10 millimetres.
• the aerosol-forming substrate within the article has a length of between 5 and 20 millimetres.
• the first hollow tube has a length of between 2 and 20 millimetres.
• the second hollow tube has a length of between 2 and 20 millimetres.
• the mouth plug filter has a length of between 5 and 20 millimetres.
• the housing of the device may be elongate.
• the housing may comprise any suitable material or combination of materials.
• suitable materials include metals, alloys, plastics or composite materials containing one or more of those materials, or thermoplastics that are suitable for food or pharmaceutical applications, for example polypropylene, polyetheretherketone (PEEK) and polyethylene.
• PEEK polyetheretherketone
• the power supply may be or comprise a battery.
• the battery may be rechargeable.
• the battery may be a Lithium-based battery, for example a Lithium-Cobalt, a Lithium-lron-Phosphate, a Lithium Titanate or a Lithium-Polymer battery, or a Nickel-metal hydride or Nickel cadmium battery.
• the power supply may be another form of charge storage device such as a capacitor.
• the power supply may have sufficient capacity to allow for the continuous generation of aerosol for a period of at least six minutes, corresponding to the typical time taken to smoke a conventional cigarette.
• aerosol-generating article may refer to an article able to generate, or release, an aerosol, for example when heated.
• aerosol-forming substrate may refer to a substrate capable of releasing an aerosol or volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate.
• the aerosol-forming substrate may comprise one or more aerosol formers or aerosol-forming materials.
• An aerosol-forming substrate may be adsorbed, coated, impregnated or otherwise loaded onto a carrier or support.
• An aerosolforming substrate may conveniently be part of an aerosol-generating article or smoking article.
• the aerosol-forming substrate is a solid aerosol-forming substrate.
• the aerosol-forming substrate may comprise both solid and liquid components.
• the aerosol-forming substrate may be a liquid aerosol-forming substrate.
• the aerosol-forming substrate comprises nicotine.
• the aerosolforming substrate comprises tobacco.
• the aerosol-forming substrate may comprise a non-tobacco containing aerosol-forming material.
• aerosol former may refer to any suitable known compound or mixture of compounds that, in use, facilitates formation of an aerosol and that is substantially resistant to thermal degradation at the operating temperature of the aerosol-generating article.
• Suitable aerosol-formers are known in the art and include, but are not limited to: polyhydric alcohols, such as propylene glycol, triethylene glycol, 1 ,3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.
• Preferred aerosol formers are polyhydric alcohols or mixtures thereof, such as propylene glycol, triethylene glycol, 1 ,3-butanediol and, most preferred, glycerine.
• the aerosol-forming substrate may comprise one or more aerosol formers.
• usage session may refer to a period in which a series of puffs are applied by a user to extract aerosol from an aerosol-forming substrate.
• a usage session may comprise at least 5 puffs. The puffs may be applied to the system, for example to the article or a mouthpiece of the device of the system.
• a usage session may refer to a session during which aerosol is extracted from an aerosol-forming substrate of an aerosol-generating article. Once the aerosol-forming substrate is depleted, the aerosol-generating article may be replaced and another usage session may be started.
• aerosol-generating device may refer to a device for use with an aerosol-generating article to enable the generation, or release, of an aerosol.
• the term “susceptor” may refer to an element comprising a material that is capable of converting the energy of a magnetic field into heat. When a susceptor is located in an alternating magnetic field, the susceptor is heated. Heating of the susceptor may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.
• the term “inductively couple” may refer to the heating of a susceptor when penetrated by an alternating magnetic field.
• the heating may be caused by the generation of eddy currents in the susceptor.
• the heating may be caused by magnetic hysteresis losses.
• the term “puff” may refer to the action of a user drawing an aerosol into their body through their mouth or nose.
• Aerosol-generating articles may comprise an upstream end through which, in use, air enters the article. Aerosol-generating articles may comprise a downstream end through which, in use, air or aerosol exits the article.
• the term “electrically insulating” may refer to a material having an electrical conductivity of less than 0.8x10 4 Siemens per metre in at least one direction, for example in all directions, at room temperature (20 degrees Celsius) and a relative humidity of 50%.
• the term “electrically conductive” may refer to a material having an electrical conductivity of at least 0.8x10 6 Siemens per metre in at least one direction, for example in all directions, at room temperature (20 degrees Celsius) and a relative humidity of 50%.
• thermally conductive may refer to a material having a thermal conductivity of at least 5, 10, 20, 50, or 100 Watts per metre-Kelvin in at least one direction, for example in all directions, at room temperature (20 degrees Celsius) and a relative humidity of 50%.
• a method of controlling an aerosol-generating system comprising: an internal heater configured to heat an aerosol-forming substrate from within the aerosolforming substrate; and an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, and the method comprising controlling a supply of power to one or both of the internal heater and the external heater during a plurality of phases, the supply of power being different for at least two phases, or for each phase, of the plurality of phases, optionally wherein the plurality of phases comprises one or more or all of a pre-heating phase, a cooling phase, a first phase, and a second phase.
• a method of controlling an aerosol-generating system comprising: an internal heater configured to heat an aerosol-forming substrate from within the aerosolforming substrate; and an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, and the method comprising: during a first phase, controlling a supply of power to one or both of the internal heater and the external heater to increase a temperature of the internal heater during the first phase; and during a second phase subsequent, for example immediately subsequent, to the first phase, controlling a supply of power to the external heater to increase a temperature of the external heater during the second phase.
• a method of controlling an aerosol-generating system comprising: an internal heater configured to heat an aerosol-forming substrate from within the aerosolforming substrate; and an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, and the method comprising: during a first phase, heating the internal heater to or maintaining the internal heater at a temperature above a first predetermined temperature; during the first phase, heating the external heater to or maintaining the external heater at a temperature below the first predetermined temperature; and during a second phase subsequent to the first phase, heating the external heater to a temperature above the first predetermined temperature.
• a method of controlling an aerosol-generating system comprising: an internal heater configured to heat an aerosol-forming substrate from within the aerosolforming substrate; and an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, and the method comprising: during a first phase, heating the internal heater to or maintaining the internal heater at a temperature above 150 degrees Celsius; during the first phase, heating the external heater to or maintaining the external heater at a temperature below 100 degrees Celsius; and during a second phase subsequent to the first phase, heating the external heater to a temperature above 150 degrees Celsius.
• the first portion of the second phase being subsequent, optionally immediately subsequent, to the first phase, heating the external heater to between 80 and 130 degrees Celsius, optionally wherein this heating is in response to detecting a first predetermined number of puffs, for example three, four, five or six puffs, on the system during the current usage session; and during a second portion of the second phase, the second portion of the second phase being subsequent, optionally immediately subsequent, to the first portion of the second phase, heating the external heater to a temperature between 130 and 400 or between 160 and 300 degrees Celsius, optionally wherein this heating is in response to detecting a second predetermined number of puffs, for example six, seven, eight, nine, or ten puffs, on the system during the current usage session.
• a first predetermined number of puffs for example three, four, five or six puffs
• a method of controlling an aerosol-generating system comprising: an internal heater configured to heat an aerosol-forming substrate from within the aerosolforming substrate; and an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate, and the method comprising any one, two or all of the following three steps: during a pre-heating phase, controlling a supply of power to one or both of the internal heater and the external heater to increase a temperature of the internal heater to at least an internal heater minimum pre-heating temperature; during a cooling phase subsequent, for example immediately subsequent, to the preheating phase, controlling a supply of power to one or both of the internal heater and the external heater to decrease a temperature of the internal heater to a temperature lower than the internal heater minimum pre-heating temperature; and during a first phase subsequent, for example immediately subsequent, to the cooling phase, controlling a supply of power to one or both of the internal heater and the external heater to increase a temperature of one or both of the internal heater and the external heater, and optionally wherein the method comprises
• a method comprising one or both of: during the first phase, one or both of controlling a supply of power to the internal heater according to a first phase internal heater power supply profile and controlling a supply of power to the external heater according to a first phase external heater power supply profile, optionally so as to increase a temperature of the internal heater during the first phase; and during the second phase, one or both of controlling a supply of power to the internal heater according to a second phase internal heater power supply profile and controlling a supply of power to the external heater according to a second phase external heater power supply profile, optionally so as to increase a temperature of the external heater during the second phase.
• Ex6 A method according to example Ex5, wherein the method comprises controlling the supply of power to the external heater according to the first phase external heater power supply profile during the first phase so as to inductively heat the susceptor.
• Ex8 A method according to any of examples Ex5 to Ex7, wherein the inductor is heated, for example resistively, to a higher temperature during the second phase than during the first phase.
• a peak temperature of the inductor during the second phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than a peak temperature of the inductor during the first phase.
• controlling a supply of power to the inductor comprises controlling one or both of a frequency and a magnitude of an alternating current supplied to the inductor.
• a method according to any of examples Ex5 to Ex12, wherein controlling the supply of power to the external heater according to the first phase external power supply profile comprises supplying an alternating current at a first frequency to the inductor.
• controlling the supply of power to the external heater according to the second phase external heater power supply profile comprises supplying an alternating current at a second frequency, different to the first frequency, to the inductor.
• Ex15 A method according to any of examples Ex5 to Ex14, wherein, compared with supplying the alternating current at the second frequency to the inductor, supplying the alternating current at the first frequency to the inductor results in one or both of: greater inductive heating of the susceptor; and less resistive heating of the inductor.
• Ex16 A method according to any of examples Ex5 to Ex15, wherein, compared with supplying the alternating current at the first frequency to the inductor, supplying the alternating current at the second frequency to the inductor results in one or both of: greater resistive heating of the inductor; and less inductive heating of the susceptor.
• a method according to any of examples Ex5 to Ex16, wherein controlling the supply of power to the external heater according to the second phase external heater power supply profile comprises supplying a direct current, alone or in combination with an alternating current, to the inductor.
• Ex20 A method according to example Ex19, wherein the pre-heating phase occurs prior to the first phase or at the start of the first phase.
• Ex21 A method according to example Ex19 or Ex20, wherein the method comprises, during the pre-heating phase, one or both of controlling a supply of power to the internal heater according to a pre-heating phase internal heater power supply profile and controlling a supply of power to the external heater according to a pre-heating phase external heater power supply profile.
• Ex23 A method according to example Ex21 or Ex22, wherein the pre-heating phase external heater power supply profile is different to one or both of the first phase external heater power supply profile and the second phase external heater power supply profile.
• a peak temperature reached by the internal heater during the pre-heating phase is greater than or equal to one or both of: a peak temperature reached by the internal heater during the first phase; and a peak temperature reached by the internal heater during the second phase.
• Ex29 A method according to any of examples Ex19 to Ex28, wherein a temperature of the internal heater is, for at least a portion of the pre-heating phase, at least 200, 300, or 400 degrees Celsius.
• Ex30 A method according to any of examples Ex19 to Ex29, wherein a temperature of the internal heater is, for at least a portion of the pre-heating phase, no more than 500 or 400 degrees Celsius.
• Ex31 A method according to any of examples Ex19 to Ex30, wherein a temperature of the internal heater is, for at least a portion of the pre-heating phase, between 200 and 500, or between 200 and 400 degrees Celsius.
• Ex32 A method according to any of examples Ex19 to Ex31 , wherein a temperature of the external heater is, for at least a portion of the pre-heating phase, at least 200, 300, or 400 degrees Celsius.
• Ex33 A method according to any of examples Ex19 to Ex32, wherein a temperature of the external heater is, for at least a portion of the pre-heating phase, no more than 500 or 400 degrees Celsius.
• Ex34 A method according to any of examples Ex19 to Ex33, wherein a temperature of the external heater is, for at least a portion of the pre-heating phase, between 200 and 500, or between 200 and 400 degrees Celsius.
• Ex35 A method according to any of examples Ex19 to Ex34, wherein the pre-heating phase lasts for at least 5, 10, 20, or 30 seconds.
• Ex36 A method according to any of examples Ex19 to Ex35, wherein the pre-heating phase lasts for no more than 60, 45 or 30 seconds.
• Ex37 A method according to any of examples Ex19 to Ex36, wherein the pre-heating phase lasts for between 5 and 60, or 5 and 45, or 10 and 45 seconds.
• a peak temperature of the internal heater during the first phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than a peak temperature of the external heater during the first phase.
• a temperature of the internal heater is, for at least a portion of the first phase, at least 150, 200, 250, or 300 degrees Celsius.
• a temperature of the internal heater is, for at least a portion of the first phase, no more than 500, 450, or 400 degrees Celsius.
• a temperature of the internal heater is, for at least a portion of the first phase, between 150 and 500, or between 200 and 450, or between 250 and 400 degrees Celsius.
• a temperature of the external heater is, for at least a portion of the first phase, at least 150, 200, 250, or 300 degrees Celsius; and a temperature of the external heater is, for at least a portion of the first phase, no more than 500, 450, or 400 degrees Celsius.
• a temperature of the external heater is, for at least a portion of the first phase, one or both of: more than 30 degrees Celsius and less than 100 or 150 degrees Celsius; and a temperature of the external heater is, for at least a portion of the second phase, one or both of: more than 100 or 150 degrees Celsius and less than 300 degrees Celsius.
• a temperature of the external heater is, for at least a portion of the first phase, between 150 and 500, or between 200 and 450, or between 250 and 400 degrees Celsius.
• Ex61 A method according to any preceding example, wherein a temperature of the internal heater is: held at a first phase first internal heater temperature for a first portion of the first phase; and held at a first phase second internal heater temperature, different to the first phase first internal heater temperature, for a second portion, subsequent to the first portion, of the first phase.
• Ex62 A method according to example Ex61 , wherein a temperature of the internal heater is held at a first phase third internal heater temperature, different to one or both of the first phase first internal heater temperature and the first phase second internal heater temperature, for a third portion, subsequent to the second portion, of the first phase.
• Ex63 A method according to any of examples Ex61 and Ex62, wherein the first phase second internal heater temperature is greater, for example at least 20, 50 or 100 degrees Celsius greater, than the first phase first internal heater temperature.
• Ex64 A method according to any of examples Ex61 , Ex62 and Ex63, wherein the first phase third internal heater temperature is greater, for example at least 20, 50 or 100 degrees Celsius greater, than the one or both of the first phase first internal heater temperature and the first phase second internal heater temperature.
• a temperature of the external heater is held constant, for example at between 100 and 300, or between 150 and 300, or between 200 and 300 degrees Celsius, or increases during at least a portion of the first phase.
• a temperature of the external heater is: held at a first phase first external heater temperature for a first portion of the first phase; and held at a first phase second external heater temperature, different to the first phase first external heater temperature, for a second portion, subsequent to the first portion, of the first phase.
• Ex71 A method according to example Ex70, wherein a temperature of the external heater is held at a first phase third external heater temperature, different to one or both of the first phase first external heater temperature and the first phase second external heater temperature, for a third portion, subsequent to the second portion, of the first phase.
• Ex72 A method according to example Ex70 or Ex71 , wherein the first phase second external heater temperature is greater, for example at least 20, 50 or 100 degrees Celsius greater, than the first phase first external heater temperature.
• Ex73 A method according to example Ex70, Ex71 , or Ex72, wherein the first phase third external heater temperature is greater, for example at least 20, 50 or 100 degrees Celsius greater, than the one or both of the first phase first external heater temperature and the first phase second external heater temperature.
• a peak temperature of the internal heater during the second phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than a peak temperature of the external heater across the second phase.
• a temperature of the internal heater is, for at least a portion of the second phase, at least 150, 200, 250, or 300 degrees Celsius.
• a temperature of the internal heater is, for at least a portion of the second phase, no more than 500, 450, or 400 degrees Celsius.
• a temperature of the internal heater is, for at least a portion of the second phase, between 150 and 500, or between 200 and 450, or between 250 and 400 degrees Celsius.
• a temperature of the external heater is, for at least a portion of the second phase, at least 150, 200, 250, or 300 degrees Celsius.
• a temperature of the external heater is, for at least a portion of the second phase, no more than 500, 450, or 400 degrees Celsius.
• a temperature of the external heater is, for at least a portion of the second phase, between 150 and 500, or between 200 and 450, or between 250 and 400 degrees Celsius.
• a temperature of the external heater at an end of the second phase is one or both of: less than a temperature which is 20, 50 or 100 degrees Celsius above a temperature of the internal heater at the end of the second phase; and greater than a temperature which is 20, 50 or 100 degrees Celsius below a temperature of the internal heater at the end of the second phase.
• a temperature of the external heater at an end of the second phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than a temperature of the external heater at a start of the second phase.
• a temperature of the external heater is: held at a second phase first external heater temperature for a first portion of the second phase; and held at a second phase second external heater temperature, different to the second phase first external heater temperature, for a second portion, subsequent to the first portion, of the second phase.
• Ex103 A method according to example Ex102, wherein a temperature of the external heater is held at a second phase third external heater temperature, different to one or both of the second phase first external heater temperature and the second phase second external heater temperature, for a third portion, subsequent to the second portion, of the second phase.
• Ex104 A method according to Example Ex102 or Ex103, wherein the second phase second external heater temperature is greater, for example at least 20, 50 or 100 degrees Celsius greater, than the second phase first external heater temperature.
• Ex105 A method according to example Ex102, Ex103, or Ex104, wherein the second phase third external heater temperature is greater, for example at least 20, 50 or 100 degrees Celsius greater, than the one or both of the second phase first external heater temperature and the second phase second external heater temperature.
• a peak temperature of the external heater during the second phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than a peak temperature of the external heater during the first phase.
• an average temperature difference between the internal heater and the external heater at a start of the second phase is greater, for example at least 20, 50 or 100 degrees Celsius greater, than an average temperature difference between the internal heater and the external heater at an end of the second phase.
• Ex11 1 A method according to any preceding example, wherein an average temperature difference between the internal heater and the external heater at one or both of a start and an end of the second phase is greater than 20, 50 or 100 degrees Celsius.
• Ex112 A method according to example Ex1 , or Ex3, or any preceding example dependent on example Ex1 or Ex3, or any other preceding example wherein the method further comprises a pre-heating phase and a cooling phase subsequent to the pre-heating phase.
• Ex113 A method according to example Ex112, wherein the cooling phase lasts for one or more of: at least 90, 120, 150, or 180 seconds; no more than 360, 300, 270, or 240 seconds; between 60 and 360, or between 60 and 300, or between 90 and 270 seconds; a duration of at least one puff, optionally at least 2, 3, or 5 puffs; no more than 10 or 8 puffs; and between 1 and 10, or between 1 and 8, or between 2 and 8, or between 3 and 8 puffs.
• Ex114 A method according to example Ex1 12 or Ex113, wherein one or both of: the cooling phase is immediately subsequent to the pre-heating phase; and the first phase is immediately subsequent to the cooling phase.
• Ex115 A method according to any of examples Ex1 12 to Ex114, wherein, during the cooling phase, a temperature of the internal heater decreases, for example from the internal heater minimum pre-heating temperature, preferably by at least 10, 20, 50 or 100 degrees Celsius.
• Ex116 A method according to any of examples Ex1 12 to Ex115, wherein, during the cooling phase, a temperature of the internal heater decreases to one or both of: a temperature less than 300 or 250 degrees Celsius; and a temperature of at least 150 or 200 degrees Celsius.
• a temperature of the external heater decreases, for example from the external heater minimum pre-heating temperature, preferably by at least 10, 20, 50 or 100 degrees Celsius.
• a temperature of the external heater decreases to one or both of: a temperature less than 300 or 250 degrees Celsius; and a temperature of at least 100, 150 or 200 degrees Celsius.
• Ex119 A method according to any of examples Ex1 12 to Ex118, wherein a fall in temperature of the internal heater over the cooling phase is greater than a fall in temperature of the external heater over the cooling phase.
• Example Ex120 A method according to any preceding example when dependent on Example Ex3, wherein the internal heater minimum pre-heating temperature is one or more of: at least 100, 200, or 300 degrees Celsius; no more than 500 or 400 degrees Celsius; and between 200 and 500, or between 200 and 400, or between 300 and 400 degrees Celsius.
• Example Ex121 A method according to any preceding example when dependent on Example Ex3, wherein the method comprises, during the pre-heating phase, controlling a supply of power to the external heater to increase a temperature of the external heater to at least an external heater minimum pre-heating temperature, optionally wherein the external heater minimum pre-heating temperature is one or more of: at least 100, 200, or 300 degrees Celsius; no more than 500 or 400 degrees Celsius; and between 100 and 500, or between 100 and 400, or between 100 and 300, or between 200 and 500, or between 200 and 400, or between 200 and 300 240 degrees Celsius.
• Ex122 A method according to any preceding example when dependent on Example Ex3, wherein the method comprises, during the first phase, controlling a supply of power to one or both of the internal heater and the external heater to increase to one or more of: increase a temperature of one or both of the internal heater and the external heater by at least 10, 20, 50, or 100 degrees Celsius; increase a temperature of the internal heater to at least 200 or 250 or 300 degrees Celsius; and increase a temperature of the external heater to at least 150 or 200 degrees Celsius.
• the method comprises, during the first phase, controlling a supply of power to one or both of the internal heater and the external heater to increase to one or more of: increase a temperature of one or both of the internal heater and the external heater by at least 10, 20, 50, or 100 degrees Celsius; increase a temperature of the internal heater to at least 200 or 250 or 300 degrees Celsius; and increase a temperature of the external heater to at least 150 or 200 degrees Celsius.
• the second phase is triggered by a predetermined number of puffs on the aerosol-forming substrate being taken during a current usage session, for example two, three, four, or five puffs on the aerosol-forming substrate being taken during a current usage session; or a predetermined time from a first puff on the aerosolforming substrate passing; or a predetermined time from an activation, for example a first activation, of the internal heater or the external heater passing; or a predetermined time from an the internal heater or the external heater reaching a predetermined temperature passing; or a predetermined time from beginning the pre-heating phase, ending the pre-heating phase, or beginning the first phase passing; or activation of a user-activatable trigger; or a combination of any one or more of these options.
• An aerosol-generating device for use as part of an aerosol-generating system, the aerosolgenerating system comprising: the aerosol-generating device; an aerosol-generating article comprising an aerosol-forming substrate; and an internal heater configured to heat the aerosol-forming substrate from within the aerosolforming substrate, and the aerosol-generating device comprising: an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate; and a controller, wherein the controller is configured to: control a supply of power to one or both of the internal heater and the external heater during a plurality of phases, the supply of power being different for at least two phases, or for each phase, of the plurality of phases.
• Ex125 An aerosol-generating device according to Ex124, wherein the device comprises the internal heater.
• Ex126 An aerosol-generating device according to Ex124, wherein the article comprises the internal heater.
• An aerosol-generating system comprising: an internal heater configured to heat an aerosol-forming substrate from within the aerosolforming substrate; an external heater configured to heat the aerosol-forming substrate from outside the aerosol-forming substrate; and a controller, wherein the controller is configured to: control a supply of power to one or both of the internal heater and the external heater during a plurality of phases, the supply of power being different for at least two phases, or for each phase, of the plurality of phases.
• Ex130 An aerosol-generating system according to any of examples Ex127 to Ex129, wherein the system comprises an aerosol-generating article comprising the aerosol-forming substrate.
• An aerosol-generating system according to any of examples Ex127 to Ex128, wherein the system comprises an aerosol-generating device, optionally the aerosol-generating device of any of examples Ex124 to Ex126, and an aerosol-generating article, wherein the aerosol-generating device is configured to engage with, for example at least partially receive, the aerosol-generating article.
• Ex135. An aerosol-generating system according to any of examples Ex127 to Ex131 , wherein the device comprises the internal heater; the device comprises the external heater; the internal heater is or comprises a susceptor; and the external heater is or comprises an inductor such as an inductor coil.
• Ex136 An aerosol-generating system according to any of examples Ex127 to Ex131 , wherein the device comprises the external heater; the article comprises the internal heater; the internal heater is or comprises a susceptor; and the external heater is or comprises an inductor such as an inductor coil.
• Ex137 An aerosol-generating system according to any of examples Ex127 to Ex131 , wherein the device comprises the internal heater; the device comprises the external heater; the internal heater is an electrically resistive heater; and the external heater is an electrically resistive heater.
• Ex138 An aerosol-generating system according to any of examples Ex127 to Ex131 , wherein the device comprises the internal heater; the device comprises the external heater; the device comprises an inductor distinct from the external heater; the external heater is an electrically resistive heater; and the internal heater is or comprises a susceptor.
• Ex139 An aerosol-generating system according to any of examples Ex127 to Ex131 , wherein the device comprises the external heater; the device comprises an inductor distinct from the external heater; the article comprises the internal heater; the external heater is an electrically resistive heater; and the internal heater is or comprises a susceptor.
• Figure 1 shows a side cross-sectional view of an aerosol-generating device according to a first embodiment
• Figure 2 shows an axial cross-sectional view of the aerosol-generating device of Figure 1 along line 1 -1 ;
• Figure 3 shows a side cross-sectional view of an aerosol-generating system comprising the aerosol-generating device of Figure 1 ;
• Figure 4 shows a side cross-sectional view of an aerosol-generating device according to a second embodiment
• Figure 5 shows a side cross-sectional view of an aerosol-generating system comprising the aerosol-generating device of Figure 4;
• Figure 6 illustrates possible forms of inductor coil for the devices of Figures 1 to 5;
• Figure 7 illustrates the provision of a thermal bridging element between the inductor coil and an aerosol-generating article
• Figure 8 is a block diagram showing an inductive heating arrangement of the aerosolgenerating devices described in relation to Figure 1 to 5;
• Figure 99A is a schematic diagram showing electronic components first embodiment of electrical circuitry of the aerosol-generating devices described in relation to Figures 1 to 5;
• Figure 9B is a schematic diagram showing a second embodiment of electrical circuitry of the aerosol-generating devices described in relation to Figures 1 to 5;
• Figure 10 illustrates an AC current supply for a first method of controlling an aerosolgenerating system according to the first or second embodiments
• Figure 11 illustrates a DC current supply for the first method of controlling an aerosolgenerating system according to the first or second embodiments
• Figure 12 illustrates temperature profiles over time for the internal and external heaters of an aerosol-generating system according to the first or second embodiment when controlled according to the first method
• Figure 13 illustrates an AC current supply for a second method of controlling an aerosolgenerating system according to the first or second embodiment
• Figure 14 illustrates a DC current supply for the second method of controlling an aerosolgenerating system according to the first or second embodiment
• Figure 15 illustrates temperature profiles over time for the internal and external heaters of an aerosol-generating system according to the first or second embodiment when controlled according to the second method
• Figure 16 illustrates an AC current supply for a third method of controlling an aerosolgenerating system according to the first or second embodiment
• Figure 17 illustrates a DC current supply for the third method of controlling an aerosolgenerating system according to the first or second embodiment
• Figure 18 illustrates temperature profiles over time for the internal and external heaters of an aerosol-generating system according to the first or second embodiment when controlled according to the third method
• Figure 19 shows a side cross-sectional view of an aerosol-generating device according to a third embodiment
• Figure 20 shows a side cross-sectional view of an aerosol-generating device according to a fourth embodiment
• Figure 21 shows a side cross-sectional view of an aerosol-generating device according to a fifth embodiment
• Figure 22 shows illustrates temperature profiles over time for internal and external heaters of an aerosol-generating system
• Figure 23 shows illustrates temperature profiles over time for internal and external heaters of an aerosol-generating system
• Figure 24 shows illustrates temperature profiles over time for internal and external heaters of an aerosol-generating system.
• FIGS 1 and 2 show an aerosol-generating device 10 in accordance with a first embodiment.
• the device 10 comprises a housing 12 defining a chamber 16 for receiving a portion of an aerosol-generating article.
• the chamber 16 comprises an open end 18 through which an aerosol-generating article may be inserted into the chamber 16 and a closed end 20 opposite the open end 18.
• a cylindrical wall 22 of the chamber 16 extends between the open end 18 and the closed end 20.
• the device 10 also comprises an external heater in the form of an inductor coil 24 comprising a plurality of windings 26 disposed within the chamber 16.
• the plurality of windings 26 of the inductor coil 24 define a lumen 28 in which a portion of an aerosol-generating article is received when the aerosol-generating article is inserted into the chamber 16.
• positioning the inductor coil 24 in direct contact with an aerosol-generating article received within the chamber 16 facilitates the transfer of heat generated by resistive heating of the inductor coil 24 to the aerosol-generating article.
• the inductor coil 24 comprises a first end 30 positioned towards the open end 18 of the chamber 16 and a second end 32 positioned towards the closed end 20 of the chamber 16.
• first end 30 and the second end 32 is received within a portion of the cylindrical wall 22 of the chamber 16 to retain the inductor coil 24 within the chamber 16.
• the cylindrical wall 22 of the chamber 16 may define first and second recesses, slots, or apertures in which the first and second ends 30, 32 of the inductor coil 24 are respectively received.
• the first and second ends 30, 32 of the inductor coil 24 may be secured to the cylindrical wall 22 of the chamber 16 by overmoulding the housing 12 over the first and second ends 30, 32 of the inductor coil 24 during manufacture of the housing 12.
• the inductor coil 24 is suspended within the chamber 16 by the first and second ends 30, 32 of the inductor coil 24 so that the windings 26 of the inductor coil 24 are spaced apart from the cylindrical wall 22 of the chamber 16. Therefore, the inductor coil 24 contacts the housing 12 only at the first and second ends 30, 32 of the inductor coil 24. Spacing the windings 26 of the inductor coil 24 from the cylindrical wall 22 of the chamber 16 defines an annular gap 34 between the cylindrical wall 22 of the chamber 16 and the windings 26 of the inductor coil 24.
• the annular gap 34 reduces or minimises the transfer of heat generated by resistive heating of the inductor coil 24 to the housing 12.
• the annular gap 34 facilitates airflow through the chamber 16 when an aerosol-generating article is received within the chamber 16.
• the inductor coil 24 is arranged concentrically about a central axis 36 of the device 10. To facilitate a secure positioning of the inductor coil 24 in the chamber 16, the first and second ends 30, 32 of the inductor coil 24 are retained by diametrically opposed portions of the cylindrical wall 22 of the chamber 16.
• the housing 12 also defines a plurality of protrusions 38 extending into the chamber 16 from the closed end 20 of the chamber 16. As will be further described below, the plurality of protrusions 38 function to maintain a gap between an end of an aerosol-generating article and the closed end 20 of the chamber 16 when the aerosol-generating article is fully inserted into the chamber 16.
• the housing 12 defines three protrusions 38 spaced equidistantly about the central axis 36 of the device 10.
• the housing 12 may define more or fewer protrusions 38 and the arrangement of the protrusions 38 at the closed end 20 of the chamber 16 may be varied.
• the aerosol-generating device 10 also comprises a controller, or control circuitry, 40 and a power supply 42 connected to the inductor coil 24.
• the control circuitry 40 is configured to control a supply of power from the power supply 42 to the inductor coil 24.
• the control circuitry 40 is configured to provide an alternating electric current from the power supply 42 to the inductor coil 24 to generate an alternating magnetic field within the chamber 16.
• Figure 3 shows a cross-sectional view of an aerosol-generating system 100 comprising the device 10 of Figure 1 and an aerosol-generating article 102.
• the article 102 comprises an aerosol-forming substrate 104 in the form of a tobacco plug, a first hollow acetate tube 106, a second hollow acetate tube 108, a mouthpiece 110, and an outer wrapper 1 12.
• the article 102 also comprises an internal heater in the form of a susceptor element 114 arranged within the aerosol-forming substrate 104.
• the control circuitry 40 provides an alternating electric current from the power supply 42 to the inductor coil 24 to generate an alternating magnetic field that inductively heats the susceptor element 1 14, which heats the aerosol-forming substrate 104 to generate an aerosol.
• the level of inductive coupling between the inductor coil 24 and the susceptor element 1 14 is affected by the frequency of the alternating current to the inductor coil 24.
• Airflow through the system 100 during use is illustrated by the dashed line 1 16 in Figure 3.
• a negative pressure is generated in the chamber 16.
• the negative pressure draws air into the chamber 16 via the open end 18 of the chamber.
• the air entering the chamber 16 then flows through the annular gap 34 between the inductor coil 24 and the cylindrical wall 22 of the chamber 16.
• the airflow reaches the closed end 20 of the chamber 16
• the air enters the article 102 through the aerosol-forming substrate 104.
• Airflow into the article 102 is facilitated by the gap maintained between the upstream end of the article 102 and the closed end 20 of the chamber 16 by the plurality of protrusions 38.
• aerosol generated by heating of the aerosol-forming substrate 104 is entrained in the airflow.
• the aerosol then flows along the length of the article 102 and through the mouthpiece 110 to the user.
• Figure 4 shows a cross-sectional view of an aerosol-generating device 150 according to a second embodiment.
• the device 150 is similar to the device 10 described with reference to Figures 1 and 2 and like reference numerals are used to designate like parts.
• the device 150 differs from the device 10 by the addition of an internal heater in the form of a susceptor element 164.
• the susceptor element 164 has an elongate shape and extends into the chamber 16 from the closed end 20 of the chamber 16.
• the susceptor element 164 extends along the central axis 36 of the device 150 so that the inductor coil 24 extends concentrically around the susceptor element 164.
• Figure 5 shows a cross-sectional view of an aerosol-generating system 170 comprising the device 150 of Figure 4 and an aerosol-generating article 172.
• the system 170 is similar to the system 100 described with reference to Figure 3 and like reference numerals are used to designate like parts.
• the system 170 differs from the system 100 by the absence of the internal heater in the form of a susceptor element in the article 172.
• the susceptor element 164 of the device 150 is received within the aerosol-forming substrate 104 of the article 172.
• Figures 4 and 5 show the susceptor element 164 as having a pin- or bladeshaped profile, thereby facilitating penetration of the aerosol-forming substrate 104 by the susceptor element 164 during insertion of the article 172 into the chamber 16 of the device 150.
• the susceptor element 164 may have a profile other than that shown in Figures 4 and 5.
• both systems 100, 170 comprise an internal heater and an external heater
• the article 102 comprises the internal heater in the form of the susceptor element 114
• the device 150 comprises the internal heater in the form of the susceptor element 164.
• Figure 6 illustrates possible coil structures for the devices illustrated in Figures 1 to 5.
• a first coil structure is marked as coil structure A.
• Coil structure A comprises a sleeve 400.
• a helical coil section 410 is formed by removal of material from the sleeve 400.
• An insulating material may be arranged within the gaps where the material of the sleeve 400 has been removed. This may have the advantage of structurally reinforcing the coil structure and may also facilitate the insertion of the aerosol generating article. It is also possible to wrap or overmould a layer of insulating material, like polyimide tape, around the helical coil section 410 or the sleeve 400. This may not significantly interfere with the heat transferred to the aerosol generating article but may improve the structural stability of the coil structure.
• a second coil structure marked as coil structure B, comprises a sleeve 500 similar to coil structure A including a helical coil section 510 obtained by material removal.
• Sleeve 500 comprises a downstream extended portion 550 which is used to couple the sleeve within the housing 12 of the chamber 16 of the device.
• Extended portion 550 comprises through-holes 520 to allow airflow through the sleeve and into the aerosol generating article.
• a third coil structure, coil structure C comprises a sleeve 600 with a helical coil section 610 and a downstream extended region 650, which comprises through-holes 620 which are greater in size and in number than for the through-holes 520 of coil structure B.
• bigger openings 620 offer the advantage of reducing the mass of the structure and therefore significantly mitigates heat losses caused by heat conduction towards end regions of the sleeve.
• one or more flat spiral coils or pancake coils could be used to both generate an alternating magnetic field within the chamber 16 and to provide for external heating from resistive heating of the coil itself.
• Such flat spiral coils could be shaped to conform to the side wall of the chamber and arranged to generate a magnetic field orthogonal to a longitudinal axis of the chamber.
• one or more flat spiral coils or pancake coils could be used to both generate an alternating magnetic field within the chamber and to provide for external heating from resistive heating of the coil itself.
• Such flat spiral coils could be shaped to conform to the side wall of the chamber and arranged to generate a magnetic field orthogonal to a longitudinal axis of the chamber.
• Figure 7 shows a cross-sectional view of an aerosol-generating device 250 according to a third embodiment.
• the device 250 is similar to the device 150 described with reference to Figures 4 and 5 and like reference numerals are used to designate like parts.
• the embodiment of Figure 7 differs from the embodiment of Figures 4 and 5 in the position of the inductor coil 224 and in the provision of a thermal bridging element 228 between the coil 224 and the aerosol generating article 172.
• the inductor coil 224 is embedded or recessed within the housing of the device 250, and the thermal bridging element 228 formed from a thermally conductive material is placed in contact with the inductor coil 224.
• the thermal bridging element 228 is in the form of an austenitic steel tube.
• the thermal bridging element 228 partially defines a cylindrical wall of the chamber that extends between the open end and the closed end of the chamber.
• the thermal bridging element 228 is arranged so that an aerosol-generating article 172 is received within the thermal bridging element 228 and in direct contact with the thermal bridging element 228 when the article is inserted into the chamber.
• direct contact between the thermal bridging element 228 and an aerosol-generating article 172 facilitates the transfer of heat from the thermal bridging element 228 to the aerosol-generating article.
• the inductor coil 224 comprises a plurality of windings that extend around an outer surface of the thermal bridging element 228.
• the inductor coil 224 is arranged so that the plurality of windings are in direct contact with the outer surface of the thermal bridging element 228.
• positioning the inductor coil 224 in direct contact with an outer surface of the thermal bridging element 228 facilitates the transfer of heat generated by resistive heating of the inductor coil 224 to the thermal bridging element 228.
• the inductor coil 224 and the thermal bridging element 228 are arranged concentrically about a central axis of the device 250.
• FIG 8 is a block diagram illustrating an exemplary configuration of components and circuitry for generating and providing an alternating current to an inductor coil of an aerosolgenerating device, such as the inductor coils 24, 224 of the aerosol-generating devices 10, 150, 250 of Figures 1 , 4 and 7.
• a DC power source 310 is coupled to an heating arrangement 320.
• the heating arrangement 320 comprises a controller 330, a DC/AC converter 340, a matching network 350 and an inductor coil 240.
• the DC power source 310 of Figure 8 corresponds to the power supply 42 of the aerosol-generating devices 10, 150, 250 of Figures 1 , 4 and 7.
• the controller 330, DC/AC converter 340 and matching network 350 correspond to the control circuitry 40 of the aerosol-generating devices 10, 150, 250 of Figures 1 , 4 and 7.
• the inductor coil 240 corresponds to the inductor coil 24, 224 of the aerosol-generating devices 10, 150, 250 of Figures 1 , 4 and 7.
• the DC power source 310 is configured to provide DC power to the heating arrangement 320.
• the DC power source 310 is configured to provide a DC supply voltage VDC and a DC current IDC to the DC/AC converter 340.
• the power source 310 is a battery, such as a lithium ion battery.
• the power source 310 may be another form of charge storage device such as a capacitor.
• the power source 310 may require recharging.
• the power source 310 may have sufficient capacity to allow for the continuous generation of aerosol for a period of around six minutes or for a period that is a multiple of around six minutes.
• the power source 310 may have sufficient capacity to allow for a predetermined number of puffs or discrete activations of the heating arrangement.
• the DC/AC converter 340 is configured to supply the inductor coil 240 with a high frequency alternating current.
• high frequency alternating current means an alternating current having a frequency of between about 500 kilohertz and about 30 megahertz.
• the high frequency alternating current may have a frequency of between about 1 megahertz and about 30 megahertz, such as between about 1 megahertz and about 10 megahertz, or such as between about 5 megahertz and about 8 megahertz.
• FIG 9A schematically illustrates a first embodiment of electrical circuitry for use in supplying the inductor coil 240 with electric energy.
• the DC/AC converter 340 preferably comprises a Class-E power amplifier.
• the Class-E power amplifier comprises a transistor switch 1320 comprising a Field Effect Transistor 1321 , for example a Metal-Oxide-Semiconductor Field Effect Transistor, a transistor switch supply circuit indicated by the arrow 1322 for supplying a switching signal (gate-source voltage) to the Field Effect Transistor 1320, and an LC load network 1323 comprising a shunt capacitor C1 and a series connection of a capacitor C2 and inductor coil L2.
• Inductor coil L2 corresponds to inductor coil 240 of Figure 8.
• DC power source 1 1 comprising a choke inductor L1 , is shown for supplying the DC supply voltage V D c, with the DC current IDC being drawn from the DC power source 11 during operation.
• the ohmic resistance R represents the total ohmic load 1324, which is the sum of the ohmic resistance R CO ii of the inductor coil L2 and the ohmic resistance Rioad of the susceptor element.
• the DC power source 11 corresponds to the DC power source 310 of Figure 8.
• the transistor switch supply circuit 1322 may supply a switching voltage having a rectangular profile to the Field Effect Transistor 1321. As long as the Field Effect Transistor 1321 is conducting (in an "on”-state), it essentially constitutes a short circuit (low resistance) so that the entire current flows through the choke Li and the Field Effect Transistor 1321. When the Field Effect Transistor 1321 is non-conducting (in an "off”-state), the entire current flows into the LC load network 1323 since the Field Effect Transistor 1321 essentially represents an open circuit (high resistance).
• Switching the Field Effect Transistor 1321 between conducting (“on”) and nonconducting (“off”) states inverts the supplied DC voltage V D c and DC current IDC into an AC voltage VAC and AC current IAC flowing in the inductor coil L2, having frequency f.
• the transistor switch supply circuit 1322 is inactive so that the supplied DC current IDC is not converted to AC current, but remains as direct current. So, the circuit of Figure 9A allows for supply to the inductor coil L2 of one of AC current IAC or DC current be , but not both l A c and be simultaneously.
• Figure 9B schematically illustrates a second embodiment of electrical circuitry for use in supplying the inductor coil 240 with electric energy.
• the circuitry of Figure 9B includes all of the components of the circuitry of Figure 9A, but includes additional circuitry. The additional circuitry is discussed below.
• a DC feed to the inductor coil L2 is provided.
• a DC power supply DCs is connected to the inductor coil L2 through a transistor switch 1326.
• An additional choke inductor L3 is arranged between DC power supply DCs and the capacitor C2.
• the transistor switch 1326 is driven by a transistor switch supply circuit indicated by the arrow 1325 for supplying the switching signal (gate-source voltage).
• the DC source DCs could be a battery or in general any means capable of producing a DC current.
• the battery could be the same power source as the one generating the DC voltage V D c for feeding to the DC/AC converter 340 in order to generate the AC current IAC-
• a DC current bc2 will flow through inductors L3 and L2.
• Choke inductor L3 has the specific purpose of preventing the AC current IAC from flowing through the DC source DCs.
• the inductance value of L3 is significantly higher than the inductance of inductor coil L2.
• choke inductor L1 does not allow AC current to flow within DC source VDC-
• the circuit of Figure 9B allows the simultaneous or alternate flow of a) AC current IAC (generated by V D c) flowing through capacitor C2, inductor coil L2 and capacitor C1 , and b) direct current bc2 through inductor L3 and inductor coil L2. Direct current bc2 does not reach choke inductor L1 because of the presence of capacitor C2, which is seen by bc2 as an open circuit.
• the circuit could also operate without the choke inductor L3, as long as the circuit is set up for operating sequentially with AC current and DC current (that is AC and DC are not to be activated simultaneously).
• inductor coil L2 is more frequency selective.
• capacitor C3 may greatly improve the process of switching from a frequency f SU sceptor to a frequency ctor coii to change from internal to external heating as a result of AC current, since the difference between the two frequency values may be significantly reduced. In this way, the control may run smoother. Without capacitor C3, the two frequency values may be distant from each other, making the system slower to react.
• the DC/AC converter 340 may use any suitable circuitry that converts DC current to AC current.
• the DC/AC converter 340 may comprise a class-D power amplifier comprising two transistor switches.
• the DC/AC converter 340 may comprise a full bridge power inverter with four switching transistors acting in pairs.
• the inductor coil 240 may receive the alternating current from the DC/AC converter 340 via the matching network 350 for optimum adaptation to the load, but the matching network 350 is not essential.
• the matching network 350 may comprise a small matching transformer.
• the matching network 350 may improve power transfer efficiency between the DC/AC converter 340 and the inductor coil 240.
• the inductor coil 24, 224 is located around the cavity 16 of the aerosol-generating device 10, 150, 250. Accordingly, the high frequency alternating current IAC supplied to the inductor coil 24, 224 during operation of the device 10, 150, 250 causes the inductor coil to generate a high frequency alternating magnetic field within the cavity 16 of the device 10, 150, 250.
• the alternating magnetic field preferably has a frequency of between 1 and 30 megahertz, preferably between 2 and 10 megahertz, for example between 5 and 7 megahertz.
• the aerosol-forming substrate 104 of the article is located adjacent to the inductor coil 24, 224 so that the susceptor element 1 14, 164, 264 is located within this alternating magnetic field.
• the alternating magnetic field penetrates the susceptor element 114, 164, 264, the alternating magnetic field causes heating of the susceptor element. For example, eddy currents are generated in the susceptor element 114, 164, 264 which is heated as a result. Further heating is provided by magnetic hysteresis losses within the susceptor element 1 14, 164, 264.
• the heated susceptor element 114, 164, 264, and/or the heated inductor coil 24, 224 heats the aerosol-forming substrate 104 of the article 102, 172 to a sufficient temperature to form an aerosol.
• the aerosol is drawn downstream through the article 102, 172 and inhaled by the user.
• the controller 330 may be a microcontroller, preferably a programmable microcontroller.
• the controller 330 is programmed to regulate the supply of power from the DC power source 310 to the inductive heating arrangement 320 in order to control the temperature of the susceptor element.
• Figures 10-12 illustrate a possible method for controlling a supply of power to an external heater, or inductor coil 24, 224, 240, for example in a system such as that shown in any of Figures 3, 5, or 7. Such a method could be implemented using the control circuitry of Figure 9B.
• Figure 10 shows how the controller 40 controls the supply of AC current IAC to the inductor coil 24, 224, 240 over time t, including over a first phase between time tO and time t1 , and over a subsequent second phase between time t1 and time t2.
• Figure 1 1 shows how the controller 40 controls the supply of DC current IDC to the inductor coil 24, 224, 240 over time t.
• Figure 12 shows how temperature T, specifically a temperature Tin of the internal heater, or susceptor 114, 164, 264, and a temperature Tex of the external heater, or inductor coil 24, 224, 240, varies over time t.
• a pre-heating phase which is part of the first phase in this embodiment, begins.
• the pre-heating phase could be considered separate to the first phase, in which case the first phase could be considered to begin at the end of the pre-heating phase at time tx.
• an AC current at a first amplitude and a first frequency is supplied to the inductor coil 24, 224, 240.
• the first amplitude is relatively large and the first frequency is selected so as to maximise coupling between the inductor coil 24, 224, 240 and the susceptor 114, 164, 264 and therefore maximise heating of the susceptor 114, 164, 264.
• the susceptor 1 14, 164, 264 quickly increases in temperature to a pre-heating phase temperature of around 380 degrees Celsius. There is little to no resistive heating of the inductor coil 24, 224, 240 during the pre-heating phase. As the skilled person would appreciate, there could be a small lag time between a change in a supply of power to a heater and a resultant change in temperature of a heater.
• instantaneous changes in the power supplied to a heater may be considered to result in an instantaneous change in temperature of a heater.
• a change in temperature over a period of less than around 5 seconds may be considered instantaneous.
• the pre-heating phase ends. Because the pre-heating phase is relatively short at around 30 seconds and the aerosolforming substrate takes time to warm up to form an aerosol, and because the user has not yet begun puffing on the system 100, 170, 270, very little or substantially no aerosol is formed during the pre-heating phase.
• the device 10, 150, 250 may alert a user that the system 100, 170, 270 is ready for puffing, for example using an audible, visual or haptic alert.
• the controller 40 adjusts the amplitude of the AC current supplied to the inductor coil 24, 224, 240 from the power supply 42 from the first amplitude a second amplitude.
• the second amplitude is smaller than the first amplitude.
• the frequency is unchanged. There is therefore less inductive heating of the susceptor 114, 164, 264 and the susceptor 114, 164, 264 falls in temperature to around 300 degrees Celsius. This AC current is maintained from time tx to time ta.
• the susceptor 114, 164, 264 is held at around 300 degrees Celsius and the susceptor 1 14, 164, 264 heats the aerosol-forming substrate 104, predominantly the innermost portion of the aerosol-forming substrate 104, to form an aerosol, or a vapour which cools and condenses to form an aerosol.
• the user may puff on the article 102, 172 of the system 100, 170, 270, resulting in an airflow as described earlier and illustrated by the dashed line 116 in Figures 3, 5 and 7, and inhale the aerosol formed.
• the susceptor 114, 164, 264 is held at around 300 degrees Celsius simply by maintaining the AC current supplied to the inductor coil 24, 224, 240 constant.
• the temperature of the susceptor 114, 164, 264 could be held roughly constant by determining or estimating a temperature of the susceptor 1 14, 164, 264 using a temperature determiner, and then adjusting one or both of the amplitude and frequency of the AC current supplied to the inductor coil 24, 224, 240 to maintain the temperature of the susceptor 114, 164, 264 accordingly.
• the controller 40 adjusts the amplitude of the AC current supplied from the power supply 42 to the inductor coil 24, 224, 240 from the second amplitude to a third amplitude.
• the frequency does not change.
• the third amplitude is greater than the second amplitude.
• the susceptor 1 14, 164, 264 is thus inductively heated more and rises in temperature to around 320 degrees Celsius.
• This AC current is maintained from time ta to time tb. Over this time, which may last around one minute, the susceptor 1 14, 164, 264 is held at around 320 degrees Celsius.
• the user may puff on the article 102, 172 of the system 100, 170, 270, resulting in an airflow as described earlier and illustrated by the dashed line 116 in Figures 3, 5 and 7, and inhale the aerosol formed.
• the controller 40 adjusts the amplitude of the AC current supplied from the power supply 42 to the inductor coil 24, 224, 240 from the third amplitude to a fourth amplitude.
• the frequency does not change.
• the fourth amplitude is greater than the third amplitude.
• the susceptor 1 14, 164, 264 is thus inductively heated more and rises in temperature to around 340 degrees Celsius.
• This AC current is maintained from time tb to time t1 . Over this time, which may last around one minute, the susceptor 1 14, 164, 264 is held at around 340 degrees Celsius.
• the user may puff on the article 102, 172 of the system 100, 170, 270, resulting in an airflow as described earlier and illustrated by the dashed line 116 in Figures 3, 5 and 7, and inhale the aerosol formed.
• time t1 at the end of the first phase, most of the inner portion of the aerosolforming substrate 104 has been heated to a sufficient temperature to form an aerosol so is depleted.
• Most of the outer portion of the aerosol-forming substrate 104, particularly the outermost portion may not have been heated to a sufficient temperature to form an aerosol so is not depleted.
• the controller 40 adjusts the amplitude and frequency of the AC current supply from the power supply 42 to the inductor coil 24, 224, 240. This amplitude and frequency are both reduced. This results in much less inductive coupling between the inductor coil 24, 224, 240 and the susceptor 114, 164, 264 and thus much less inductive heating of the susceptor 1 14, 164, 264, so the temperature Tin of the susceptor 114, 164, 264 gradually falls over the course of the second phase from time t1 to time t2. In addition, this AC current supply results in some resistive heating of the external heater (the inductor coil 24, 224, 240).
• the controller 40 could cease supply an AC current to the inductor coil 24, 224, 240 completely during the second phase. This would result in the temperature of the susceptor 1 14, 164, 264 falling more quickly over the second phase.
• a DC current is supplied from the power supply 42 to the inductor coil 24, 224, 240.
• This DC current increases substantially instantaneously at time t1 , then substantially linearly from time t1 to time t2.
• the temperature of the external heater Tex increases substantially instantaneously at time t1 due to the AC and DC currents, then roughly linearly increases over the second phase from time t1 to time t2 due to the linearly increasing DC current, reaching a final temperature of around 320 degrees Celsius at time t2.
• the substrate is substantially entirely depleted.
• the temperature of the external heater Tex is within 50 degrees Celsius of, and slightly less than, the temperature of the internal heater Tin.
• Figures 13-15 illustrate a second possible method for controlling a supply of power to the external heater, or inductor coil 24, 224, 240, for example in a system such as that shown in any of Figures 3, 5, or 7 (which show the devices 100, 150, 250 of Figures 1 , 4, or 7 respectively). Such a method could be implemented using the control circuitry of Figure 9B for example.
• Figure 13 shows how the controller 40 controls the supply of AC current IAC to the inductor coil 24, 224, 240over time t, including over a pre-heating phase between time tO and tx, a first phase between time tx and time t1 , and a second phase between time t1 and time t2.
• Figure 14 shows how the controller 40 controls the supply of DC current IDC to the inductor coil 24, 224, 240 over the same time t.
• Figure 15 shows how temperature T, specifically a temperature Tin of the internal heater, or susceptor 114, 164, 264, and a temperature T ex of the external heater, or inductor coil 24, 224, 240, over the same time t.
• the pre-heating phase begins.
• the pre-heating phase could be considered part of the first phase, in which case the first phase could be considered to begin at time tO.
• an AC current at a first amplitude and a first frequency is supplied to the inductor coil 24, 224, 240.
• the first frequency is selected to maximise inductive coupling between the inductor coil 24, 224, 240 and the susceptor 1 14, 164, 264 and therefore maximise heating of the susceptor 114, 164, 264.
• the susceptor 114, 164, 264 quickly increases in temperature to a pre-heating phase temperature of around 380 degrees Celsius.
• the pre-heating phase ends. Because the pre-heating phase is relatively short at around 30 seconds and the aerosol-forming substrate takes time to warm up to form an aerosol, and because the user has not yet begun puffing on the system 100, 170, 270, very little or substantially no aerosol is formed during the pre-heating phase.
• the device 10, 150, 250 may alert a user that the system 100, 170, 270 is ready for puffing, for example using an audible, visual or haptic alert.
• the first phase begins and the controller 40 adjusts the frequency of the AC current supplied to the inductor coil 24, 224, 240 from the power supply 42 from the first frequency to a second frequency.
• the second frequency which is lower than the first frequency, provides less inductive coupling between the inductor coil 24, 224, 240 and the susceptor 114, 164, 264 than the first frequency. There is therefore less inductive heating of the susceptor 1 14, 164, 264 and the susceptor 114, 164, 264 falls in temperature to around 300 degrees Celsius.
• This AC current is maintained for the first phase from time tx to time t1 and for the second phase from time t1 to time t2.
• the susceptor 114, 164, 264 is held at around 300 degrees Celsius. This AC current between time tx and time t2 may also result in some resistive heating of the external heater (inductor coil 24, 224, 240).
• the controller 40 supplies a DC current from the power supply 42 to the inductor coil 24, 224, 240.
• This DC current is held constant for around one minute before being increased at time ta. Further increases and holdings of the DC current for one minute are repeated at times tb, tc, and td.
• the DC current resistively heats the external heater, or inductor coil 24, 224, 240.
• the temperature Tex of the external heater follows a similar pattern to the DC current.
• the temperature Tex of the external heater is around 100 degrees Celsius between time tx and time ta, around 160 degrees Celsius between time ta and time tb, around 220 degrees Celsius between time tb and time tc, around 280 degrees Celsius between time tc and time td, and around 340 degrees Celsius between time td and time t2.
• Each of these time periods lasts around one minute.
• the second phase may be considered to start, for example, at time t1 between times ta and tb.
• the temperature of the internal heater, the susceptor 114, 164, 264 is held roughly constant across the first and second phases, and the temperature of the external heater, the inductor coil 24, 224, 240, is increased stepwise in 5 steps across the first and second phases.
• the user may puff on the article 102, 172 of the system 100, 170, 270, resulting in an airflow as described earlier and illustrated by the dashed line 1 16 in Figures 3, 5 and 7, and inhale the aerosol formed.
• the internal heater, the susceptor 114, 164, 264 heats the inner portion of the substrate to form an aerosol.
• heat propagates outwardly from the internal heater to heat more of the substrate, but the outer portion of the substrate is not sufficiently heated to form a substantial quantity of aerosol.
• time t1 at the end of the first phase, most of the inner portion of the aerosol-forming substrate 104 has been heated to a sufficient temperature to form an aerosol so is depleted.
• the external heater is at a reasonably high temperature.
• the external heater with some help from the internal heater, heats the outer portion of the substrate to form an aerosol.
• the external heater temperature increases step-wise so as to make heat propagate further inwardly from the external heater to heat more of the substrate to form an aerosol.
• time t2 at the end of the second phase, most of the outer portion of the aerosol-forming substrate 104 has been heated to a sufficient temperature to form an aerosol so is depleted.
• the substrate is substantially entirely depleted at the end of the second phase.
• Figures 16-18 illustrate a third possible method for controlling a supply of power to the external heater, or inductor coil 24, 224, 240, for example in a system such as that shown in any of Figures 3, 5, or 7. Such a method could be implemented using the control circuitry of Figure 9B for example.
• the first phase begins at time tO and ends at time t1 , three minutes after tO.
• the second phase begins at time t1 and ends at time t2, three minutes after t1 . There is no pre-heating phase.
• An AC current is supplied to the inductor coil 24, 224, 240 over the first and second phases, between time tO and time t2.
• the frequency and amplitude of this AC current do not change.
• the frequency of the AC current is selected to maximise heating of the susceptor 1 14, 164, 264.
• the internal heater temperature Tin, the temperature of the susceptor 1 14, 164, 264 thus increases to an operating temperature substantially instantaneously at time tO and then remains roughly constant across the rest of the first and second phases. In this embodiment, this operating temperature is around 320 degrees Celsius. There is little to no resistive heating of the inductor coil 24, 224, 240 during the first phase.
• a DC current is supplied to the inductor coil 24, 224, 240 over the second phase, between time t1 and time t2.
• the amplitude of this DC current rises instantaneously at time t1 to a nonzero value, then increases linearly from the first, non-zero value at time t1 to a second, greater value at time t2.
• the external heater temperature Tex (the temperature of the inductor coil 24, 224, 240) follows a similar pattern; the external heater temperature Tex (the temperature of the inductor coil 24, 224, 240) rises from room temperature TO to around 200 degrees Celsius within a few seconds after t1 , then increases substantially linearly to around 300 degrees Celsius at time t2.
• the power supplied to the heaters may be controlled in many different ways to provide many different, desirable temperature profiles for the internal and external heaters over time.
• the temperature of the external heater (inductor coil 24, 224, 240) may be controlled by controlling one or both of an AC current and a DC current supplied to the external heater (inductor coil 24, 224, 240).
• the temperature of the internal heater (susceptor 114, 164, 264) may be controlled by controlling the AC current supplied to the external heater (inductor coil 24, 224, 240). Controlling AC current may comprise controlling one or both of amplitude and frequency.
• control circuitry may be configured to control the switches 1320 and 1326 shown in Figure 9 to control these supplies of AC and DC current. This may allow the controller to follow a particular desired temperature profile for the internal and external heaters over time.
• control methods such as those illustrated in Figures 10-18, the internal heater heats the inner portion of the substrate sufficiently to form an aerosol during the first phase, and then the external heater heats the outer portion of the substrate sufficiently to form an aerosol during the second phase.
• the temperature of the external heater increases as the second phase progresses such that heat propagates inwardly from the outermost portion of the substrate to heat more of the substrate sufficiently to form an aerosol as the second phase progresses.
• most of the inner and outer portions of the substrate may have been heated sufficiently to form an aerosol.
• FIG 19 shows an aerosol-generating system 1900 in accordance with a third embodiment.
• the aerosol-generating system 1900 comprises an aerosol-generating device 1910 and the aerosol-generating article 172 shown in Figures 5 and 7.
• the device 1910 appears similar to the device 170 shown in Figures 4 and 5 but, as explained in more detail below, the inductor coil and susceptor element are replaced by an electrically resistive external heater and an electrically resistive internal heater respectively.
• the controller 40 and power supply 42 of the device 170 are present in the device 1910 but are not visible in Figure 19.
• Like reference numerals are used to designate like parts and only the differences are described here.
• the device 1910 does not comprise an inductor coil. Instead of the inductor coil, the device 1910 comprises an electrically resistive, external heater 1924.
• the external heater 1924 comprises a substantially tubular, electrically insulating substrate, and an electrically conductive track on the electrically insulating substrate.
• the controller 40 is configured to control a supply of power from the power supply 42 to the external heater 1924, specifically to control a supply of electrical current through the electrically conductive track, to resistively heat the external heater 1924 in use.
• the device 1910 also does not comprise susceptor element. Instead of the susceptor element, the device 1910 comprises an electrically resistive, internal heater 1914.
• the internal heater 1914 is shaped as a pin, blade, or rod for penetrating an aerosol-forming substrate of an aerosol-generating article inserted into the chamber of the device 1910.
• the internal heater 1914 comprises a substantially blade-shaped, electrically insulating substrate, and an electrically conductive track on the electrically insulating substrate.
• the controller 40 is configured to control a supply of power from the power supply 42 to the internal heater 1914, specifically to control a supply of electrical current through the electrically conductive track, to resistively heat the internal heater 1914 of the device 1910 in use.
• the controller 40 could control supplies of power to the internal heater 1714 and the external heater 1724 to provide the temperature profiles shown in any of Figures 12, 15 and 18.
• the device 1910 could comprise two power supplies connected to the controller 40, one power supply for supplying power to the internal heater 1914 and one power supply for supplying power to the external heater 1924.
• Figure 20 shows an aerosol-generating system 2000 in accordance with a fourth embodiment.
• the system 2000 comprises an aerosol-generating device 2010 and the aerosolgenerating article 172 shown in Figures 5 and 7.
• the device 2010 appears similar to the device 170 shown in Figures 4 and 5 but, as explained in more detail below, the inductor coil does not act as an external heater. Rather, a separate, electrically resistive heating element is introduced.
• the controller 40 and power supply 42 of the device 170 are present in the device 2010 but are not visible in Figure 20.
• Like reference numerals are used to designate like parts and only the differences are described here.
• the device 2010 shown in Figure 20 comprises a susceptor element 164 and an inductor coil 24 for inductively heating the susceptor element 164.
• the inductor coil 24 is located within the housing of the device 2010.
• the inductor coil 24 does not act as the external heater.
• the device comprises an electrically resistive, external heater 2024.
• the external heater 2024 is identical to the external heater 1924 shown in Figure 19.
• the external heater 2024 comprises a polymeric material and at least one of graphite, a graphite-derived material, and hexagonal boron nitride dispersed within the polymeric material.
• the polymeric material comprises at least one of polyether ether ketone (PEEK) and a liquid crystal polymer (LCP).
• the external heater 2024 comprises the polymeric material in an amount of 27 percent by weight of the external heater, though this amount could be between 22 percent and 33 percent.
• the graphite-derived material comprises at least one of expanded graphite and graphite nanoplatelets.
• the external heater comprises the at least one of graphite, a graphite-derived material, and hexagonal boron nitride in an amount of 65 percent by weight of the external heater, though this could be between 62 percent and 69 percent.
• the external heater further comprises an additive, carbon black, dispersed within the polymeric material.
• the external heater comprises the additive in an amount of 7 percent by weight of the external heater, though this could be between 5 percent and 9 percent.
• the external heater 2024 is not inductively heatable material and has no interaction, or a negligible interaction, with the alternating magnetic field generated by the inductor 24 in use.
• the controller 40 is configured to control a supply of power from the power supply 42 to the external heater 2024 to heat the external heater 2024.
• the controller 40 is also configured to control a supply of power from the power supply 42 to the inductor coil 24, specifically to control a supply of an alternating current to the inductor coil 24, to generate an alternating magnetic field in the chamber and thus inductively heat the susceptor element 164 (internal heater) of the device 2010 in use.
• the controller 40 could control supplies of power to the external heater 2024 and the inductor 24 to provide the temperature profiles shown in any of Figures 12, 15 and 18.
• the device 2010 could comprise two power supplies connected to the controller 40, one power supply for supplying power to the internal heater 2014 and one power supply for supplying power to the external heater (inductor coil 24).
• FIG. 21 shows an aerosol-generating system 2100 in accordance with a fifth embodiment.
• the aerosol-generating system 2100 comprises an aerosol-generating device 21 10 and the aerosol-generating article 102 shown in Figure 3.
• the aerosol-generating device 21 10 is similar to the aerosol-generating device 100 shown in Figures 1 and 3.
• the controller 40 and power supply 42 of the device 100 are present in the device 2110 but are not visible in Figure 21.
• Like reference numerals are used to designate like parts and only the differences are described here.
• the device 2110 shown in Figure 21 comprises an inductor coil 24.
• the inductor coil 24 is located within the housing of the device 2110.
• the inductor coil 24 does not act as the external heater.
• the device 2110 comprises an electrically resistive, external heater 2124 similar to the external heater of the embodiment shown in Figure 19.
• the external heater 2124 comprises a substantially tubular, electrically insulating substrate, and an electrically conductive track on the electrically insulating substrate.
• the controller 40 is configured to control a supply of power from the power supply 42 to the external heater 2124, specifically to control a supply of electrical current through the electrically conductive track, to heat the external heater 2124.
• the controller 40 is also configured to control a supply of power from the power supply 42 to the inductor coil 24, specifically to control a supply of an alternating current to the inductor coil 24, to generate an alternating magnetic field in the chamber and thus inductively heat the susceptor element 1 14 (internal heater) of the aerosolgenerating article 102 in use.
• the controller 40 could control supplies of power to the external heater 2124 and the inductor 24 to provide the temperature profiles shown in any of Figures 12, 15 and 18.
• the device 2110 could comprise two power supplies connected to the controller 40, one power supply for supplying power to the inductor coil 24 and one power supply for supplying power to the external heater 2124.
• Figure 22 illustrates internal heater and external heater temperature profiles on graphs of temperature T against time t, similar to Figures 12, 15 and 18, for a further possible method for controlling a supply of power in an aerosol-generating system with an internal heater and an external heater.
• the aerosol-generating system could be any aerosol-generating system described herein, for example any of the systems illustrated in Figures 3, 5, 7, 19, 20 or 21 .
• the internal heater and external heater are at room temperature, TO.
• the user activates the system and the temperatures of the internal and external heaters are raised as quickly as possible so as to minimise a time required to generate an aerosol for a first puff for a user.
• the temperature of the internal heater Tin is increased to around 350 degrees Celsius.
• the temperature of the external heater Tex is increased to around 240 degrees Celsius. These temperatures are then maintained for around 20 seconds until time tz, when the pre-heating phase ends and the cooling phase begins.
• the system may indicate to the user that the system is ready for puffing and the user may begin puffing. Also at time tz, the power supplied to the heaters is reduced or stopped so as to gradually decrease the temperatures of the heaters.
• the temperature of the internal heater Tin falls from around 350 degrees Celsius to around 250 degrees Celsius.
• the temperature of the external heater Tex falls from around 240 degrees Celsius to around 200 degrees Celsius. Then, for the remainder of the time to tx, the temperature of the external heater Tex is maintained at around 200 degrees Celsius.
• the cooling phase may last for about one or two minutes. During this time, the user may puff on the system and inhale an aerosol, for example as described in more detail for the systems of Figures 3, 5, 7, 19, 20, and 21.
• the cooling during the cooling phase may allow sufficient aerosol generation to satisfy a user in their first few puffs of the usage session without depleting so much aerosol-forming substrate that there is little non-depleted aerosolforming substrate left for later puffs.
• the temperature of the internal heater is controlled so as to gradually increase, in this case linearly increase, from around 250 degrees Celsius at time tx to around 300 degrees Celsius at time t1 .
• the temperature of the external heater is held constant at around 200 degrees Celsius.
• the first phase may last for around four or five minutes, and the user may puff on the system as they wish during this time.
• the temperature of the internal heater Tin increases so as to ensure that there is sufficient aerosol generation during the later puffs, even though some of the aerosol-forming substrate has been depleted during the earlier puffs.
• the temperature of the external heater Tex could also be increased during the first phase. This could advantageously aid aerosol generation during the later puffs.
• the temperature of the external heater Tex could be increased, for example, across the minute leading up to time t1 , from 200 degrees Celsius to 250 degrees Celsius.
• the embodiment could be considered to have a second phase beginning at or shortly before increasing the temperature of the external heater (so at or shortly before one minute before time t1 ).
• Figure 23 illustrates internal heater and external heater temperature profiles on graphs of temperature T against time t, similar to Figures 12, 15, 18 and 22, for a further possible method for controlling a supply of power in an aerosol-generating system with an internal heater and an external heater. This method is in line with the first preferred method described earlier in this application.
• the aerosol-generating system could be any aerosol-generating system described herein, for example any of the systems illustrated in Figures 3, 5, 7, 19, 20 or 21 .
• the internal heater and external heater are at room temperature, TO.
• the user activates the system.
• the aim during the pre-heating phase is to raise the temperatures of both the internal heater and external heater as quickly as possible.
• the internal heater is prioritised for the first three seconds of the preheating phase. After these first three seconds, the power supply alternates between supplying power to the internal heater and supplying power to the external heater multiple times per second. As such, after the first three seconds of the pre-heating phase, the internal heater Tin will cool slightly whilst power is supplied to the external heater, and the external heater will cool slightly when power is supplied to the internal heater.
• the system may indicate to the user that the system is ready for puffing and the user may begin puffing.
• the power supplied to the internal heater is controlled so as to decrease the temperature of the internal heater Tin. From time tz to time tx, the temperature of the internal heater Tin falls from around 250 degrees Celsius to around 190 degrees Celsius. From time tz to time tx, the temperature of the external heater Tex is maintained at around 80 degrees Celsius.
• the cooling phase may last for about one minute. During this time, the user may puff on the system and inhale an aerosol, for example as described in more detail for the systems of Figures 3, 5, 7, 19, 20, and 21.
• the pre-heating phase and subsequent cooling phase may allow quick aerosol generation for a first puff and avoid depleting so much aerosol-forming substrate during the first two puffs that there is little non-depleted aerosol-forming substrate left for later puffs.
• the first phase begins. From time tx to time t2, so across the entirety of the first and second phases, the power to the internal heater is controlled to maintain the temperature of the internal heater Tin at around 190 degrees Celsius.
• the temperature of the external heater is held constant at around 80 degrees Celsius.
• the first phase may last for around two minutes, and the user may puff on the system as they wish during this time.
• the second phase begins. Initiation of the second phase in this embodiment is triggered by three minutes and twenty seconds passing since first activation of the system (corresponding to twenty seconds for the pre-heating phase, one minute for the cooling phase, and two minutes for the first phase).
• the second phase could alternatively be initiated by detection of a particular puff, such as the fourth puff, on the system during the current usage session.
• the power supplied to the external heater is controlled to increase the temperature of the external heater Tex roughly constantly with time until a maximum acceptable temperature is reached, the maximum acceptable temperature being around 210 degrees Celsius in this embodiment.
• the temperature of the external heater increases from around 80 degrees Celsius at time t1 to around 210 degrees Celsius at a time around 8 minutes after time t1 .
• time t2 is around 9 minutes after time t1 .
• the second phase ends and the usage session ends and the system alerts the user accordingly.
• the temperature of the external heater Tex increases from around 80 to around 210 degrees Celsius.
• the higher temperature of the external heater advantageously means that the internal heater is cooled to a lesser extent by relatively cool air. This allows the internal heater to continue producing a substantial quantity of aerosol from the inner portion of the substrate. Then, during the later portion of the second phase, the external heater is sufficiently hot to generate an aerosol from the outer portion of the substrate, thus minimising the amount of substrate that is wasted.
• activation at time tO may initiate the first phase.
• the controller may heat the internal heater to around 190 degrees Celsius and the external heater to 80 degrees Celsius. This may take less than 20 seconds.
• the system may then alert the user that the system is ready for puffing.
• the second phase in response to a predetermined time from first activation, for example two or three minutes, the second phase may be initiated.
• the second phase could be activated in response to detection of a particular puff, for example the third, fourth, fifth or sixth puff, on the system since activation (so during the current usage session).
• the second phase may be identical to that described with reference to Figure 23.
• Figure 24 illustrates internal heater and external heater temperature profiles on graphs of temperature T against time t, similar to Figures 12, 15, 18, 22 and 23, for a further possible method for controlling a supply of power in an aerosol-generating system with an internal heater and an external heater. Similarly to Figure 22, this method is in line with the first preferred method described earlier in this application.
• the aerosol-generating system could be any aerosolgenerating system described herein, for example any of the systems illustrated in Figures 3, 5, 7, 19, 20 or 21.
• a pre-heating phase from time tO to tz there is a pre-heating phase from time tO to tz, a cooling phase from time tz to tx, a first phase from time tx to time t1 , a second phase from t1 to t2.
• the temperature of the internal heater, Tin, and the temperature of the external heater Tex are shown during these phases.
• the temperature of the internal heater, Tin is shown in a solid line and the temperature of the external heater Tex, is shown in a dotted line.
• the internal heater and external heater are at room temperature, TO.
• the user activates the system.
• the aim during the pre-heating phase is to raise the temperatures of both the internal heater and external heater as quickly as possible.
• the internal heater is prioritised for the first three seconds of the preheating phase. After these first three seconds, the power supply alternates between supplying power to the internal heater and supplying power to the external heater multiple times per second. As such, after the first three seconds of the pre-heating phase, the internal heater Tin will cool slightly whilst power is supplied to the external heater, and the external heater will cool slightly when power is supplied to the internal heater.
• the power supplied to the internal heater and to the external heater is stopped, or drastically reduced, to rapidly decrease the temperatures of the internal and external heaters.
• the temperatures of the internal and external heaters are monitored during this fall in temperature. Once the temperature of the internal heater Tin falls from around 250 degrees Celsius to around 190 degrees Celsius and the temperature of the external heater Tex falls from around 170 to around 1 10 degrees Celsius, which both occur at around time tx in this embodiment, around 60 seconds after time tz, the cooling phase ends and the first phase begins.
• the pre-heating phase and subsequent cooling and first phases may allow quick aerosol generation for a first puff but avoid depleting so much aerosol-forming substrate during the first few puffs that there is little non-depleted aerosol-forming substrate left for later puffs.
• the power supplied to the internal heater is controller to maintain the temperature of the internal heater Tin at around 190 degrees Celsius.
• the target temperature of the external heater is increased in response to each puff being detected.
• the first phase ends and the second phase starts when the third puff on the system is detected.
• the temperature of the external heater Tex is maintained at around 1 10 degrees Celsius until the fourth puff is detected.
• the target temperature for the external heater increases by around 15 degrees Celsius to around 125 degrees Celsius. So the controller controls the supply of power to the external heater to increase the temperature of the external heater Tex to 125 degrees Celsius.
• the target temperature of the external heater is increased by 15 degrees Celsius.
• the target temperature for the external heater Tex is increased from 230 to 245 degrees Celsius.
• 245 degrees Celsius is considered a maximum acceptable temperature for the external heater.
• the target temperature for the external heater is maintained at 245 degrees Celsius.
• the fourteenth puff is the final puff.
• the second phase ends and the system alerts the user that the usage session has finished and stops supplying power to the internal and external heaters.
• the temperature of the external heater Tex increases.
• the higher temperature of the external heater advantageously means that the internal heater is cooled to a lesser extent by relatively cool air. This allows the internal heater to continue producing a substantial quantity of aerosol from the inner portion of the substrate. Then, during the later portion of the second phase, the external heater is sufficiently hot to generate an aerosol from the outer portion of the substrate, thus minimising the amount of substrate that is wasted.

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  • 2024-04-29 EP EP24721690.6A patent/EP4704620A1/de active Pending
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