Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B19/00—Engines characterised by precombustion chambers
  • F02B19/02—Engines characterised by precombustion chambers the chamber being periodically isolated from its cylinder
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/46—Component parts, details, or accessories, not provided for in preceding subgroups
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
  • F01L9/20—Valve-gear or valve arrangements actuated non-mechanically by electric means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B9/00—Engines characterised by other types of ignition
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B9/00—Engines characterised by other types of ignition
  • F02B9/02—Engines characterised by other types of ignition with compression ignition
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D41/0047—Controlling exhaust gas recirculation [EGR]
  • F02D41/006—Controlling exhaust gas recirculation [EGR] using internal EGR
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/40—Engine management systems

Definitions

• the invention relates to a method for initiating combustion in an internal combustion engine, as well as to an application engine.
• Some conventional methods involve locally initiating the combustion of the mixture or by generating a spark
• the object of the invention is a new process for initiating combustion in such an engine, which is simple to implement, and which makes it possible to obtain homogeneous self-ignition in a wide operating range of the engine.
• a combustion initiation method is proposed in an internal combustion engine comprising: a main chamber of variable volume in which a flammable mixture is introduced;
• the method comprises the step of putting in communication the auxiliary chamber and the main chamber during a period including the top dead center between the compression phase and the de- tent phase.
• auxiliary chamber placed in communication with the main chamber makes it possible to release in the main chamber very hot burnt gases that had been stored during a previous cycle, these gases being sufficiently hot to cause a heating of the mixture which achieved at a plurality of sites its autoignition temperature.
• the mixture thus self-ignites homogeneously.
• the mixture is ignited, around the top dead center, the mixture burns and generates flue gases that reach a high pressure and a high temperature.
• the auxiliary chamber is then closed shortly after the top dead center to trap therein a quantity of very hot burnt gases which will serve to initiate the ignition of the mixture during the next cycle.
• the flue gases thus stored are also likely to contain reactive species that also contribute to initiate combustion of the mixture in the main chamber.
• This combustion can be very simply controlled by regulating the amount and the moment of introduction of the hot gases into the main chamber, by an adequate control of the communication means.
• the method can therefore be implemented in a wide range of engine operation.
• the auxiliary chamber is put in communication with the main chamber, at the very moment of combustion.
• the burnt gases stored in the auxiliary chamber are therefore extremely hot, and remain at very high pressure, and in any case always higher than that of the main chamber.
• This method therefore differs essentially from known methods for this type of engine in which the control valve is open well after combustion.
• the auxiliary chamber is placed in communication with the main chamber during an interval encompassing the bottom dead point between the expansion phase and the exhaust phase.
• the flue gases are then substantially cooled and are at a low pressure, of the order of 1 to 2 bars above atmospheric pressure.
• the burnt gases thus stored can not contribute to the self-ignition of the mixture when they are reintroduced into the main chamber.
• the auxiliary chamber is placed in communication with the main chamber around the point low dead between admission and compression to inject the burnt gases that are stored in the auxiliary chamber, the burnt gases having been previously stored by placing in communication the auxiliary chamber with the main chamber during the relaxation phase, so after the top dead center between compression and relaxation.
• the burned gases are stored while they have already undergone a significant cooling due to expansion, and they are reinjected at the time of admission, so at a time when they can not initiate the self-ignition of the mixture because this it is not yet compressed.
• the auxiliary chamber is brought into communication with the main chamber a first time during compression, and a second time during expansion, precisely excluding the combustion phase in the vicinity of the neutral position. high between these two phases.
• the auxiliary chamber is placed in communication twice with the main chamber, during expansion and during compression, on both sides of the top dead center between these two phases.
• the method of the invention is to put in communication the auxiliary chamber and the main chamber precisely for a period encompassing the top dead center between compression and expansion.
• the flue gases are expelled during the expansion cycle and their temperature is therefore lowered to a value such that the expelled gases are no longer reactive or hot enough to cause self-ignition by themselves. mixing in the master bedroom. On the contrary, they serve to dilute the mixture and lower its temperature in order to reduce the production of nitrogen oxides.
• FIG. 1 is a partial sectional view of a piston engine at a main chamber
• FIG. 2 is a diagram showing, as a function of the crankshaft angle, the changes in the temperature in the various chambers of the engine illustrated in FIG. 1;
• FIG. 3 is a diagram showing, as a function of the crankshaft angle, the evolutions of the pressure in the various chambers of the engine illustrated in FIG.
• the method of the invention is preferably implemented by means of a motor as shown in FIG. 1.
• This engine comprises, in a conventional manner, an engine block 1 in which cylinders 2 are formed. (Only one is visible here), closed in the upper part by a cylinder head 3.
• a piston 4 slides sealingly.
• a main chamber 5 of variable volume is thus defined in each cylinder 2 between the cylinder head 3 and the piston 4.
• An exhaust valve 7 is slidably mounted on the cylinder head 3 to be movable between a closed position isolating the main chamber 5 of an exhaust duct 8 and an open position putting in communication the main chamber and the exhaust duct 8 Similarly, and although this is not visible in Figure 1, an intake valve is slidably mounted on the cylinder head 3 to be movable between a closed position isolating the main chamber 5 of an intake duct and a open position communicating the main chamber 5 and the intake duct. All this is well known and does not form the subject of the invention.
• the yoke 3 defines an auxiliary chamber 10 extending in the immediate vicinity of the main chamber 5 to open into the latter.
• the auxiliary chamber is here coated internally with a thermal insulation. 12.
• a control valve 11 is slidably mounted on the yoke 3 to be movable between a closed position insulating the main chamber 5 of the auxiliary chamber 10 and an open position putting the main chamber 5 in communication with the auxiliary chamber 10
• the control valve 11 is here actuated by an electromechanical actuator 14.
• a glow plug 13 is mounted on the cylinder head 3 to project into the auxiliary chamber 10. The actuator 14 of the control valve 11 and the glow plug 13 are controlled by a calculator 15.
• the thermal cycle used is a four-stroke cycle, namely admission, compression, expansion, exhaust.
• the crank angles on the abscissa are counted in a conventional manner, the 360 degree angle corresponding to the top dead center between the compression phase and the expansion phase.
• the cycle begins with an admission phase during which a mixture of air and fuel is admitted into the main chamber. Then during the compression phase, the pressure and the temperature in the main chamber 5 increase progressively, as illustrated by the beginning of the curves in solid lines.
• This stirring causes the mixture to heat up in the main chamber 5, as is visible on the curve in solid lines, since the hot gases are at a higher temperature than the mixture.
• the mixture is sufficiently warmed to reach its autoignition temperature.
• the mixture then enters into combustion by auto-ignition.
• the multiplicity of self-ignition sites generated by the mixing of the hot gases with the mixture ensures a homogeneous auto-ignition.
• the self-ignition is reflected in the curves by the sudden rise in temperature and pressure, in concert in the main chamber 5 and in the auxiliary chamber 10.
• the engine control conditions in particular the compression ratio
• the characteristics of the reactive mixture intake pressure, temperature and composition
• the hot gases introduced into the main chamber thus contribute to heating up the mixture, which thus reaches its autoignition temperature, but they also contribute to dilute the mixture, thus making it possible to control the burning rate of the mixture by introducing local heterogeneities. which avoid mass combustion.
• the dilution of the mixture reduces the richness thereof, which avoids the generation of nitrogen oxides during the combustion of the mixture.
• the control valve has the particularity of being inverted with respect to the other valves. Indeed, as is clearly visible in FIG. 1, the seat 16 of the control valve 11 is turned towards the inside of the auxiliary chamber 10. Here, the control valve 11 closes against its seat down, while the other valves close against their seat up.
• the method of the invention provides that, when the auxiliary chamber 10 is closed, the pressure the auxiliary chamber 10 is always greater than the pressure in the main chamber 5.
• the inverted mounting of the control valve 11 thus allows that the control valve 11 is confirmed in the closed position against its seat 16 by the pressure in the auxiliary chamber 10 which is greater than the pressure in the main chamber 5.
• crankshaft angles at which the opening and closing of the control valve take place are given here as an indication. It will of course be desirable to vary them to take into account, in particular, the engine rotation speed and the ignition time of the mixture. It will preferably be done so that the pressure peak occurs while the piston is substantially in the " dead center " , preferably a few degrees after said top dead center, for example by playing on the moment and / or the duration of the opening.
• the period during which the auxiliary chamber will be in communication with the main chamber will preferably extend in a range of substantially plus or minus 30 degrees around the top dead center between compression and expansion.
• the cylinder head forms the auxiliary chamber and carries an inverted seat control valve
• the chamber in which the hot gases are stored can be deported, the hot gases being reintroduced into the main chamber by means for example of an injector.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Combustion Methods Of Internal-Combustion Engines (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2007
  • 2007-04-10 FR FR0702614A patent/FR2914962B1/fr not_active Expired - Fee Related
• 2008
  • 2008-04-07 WO PCT/FR2008/000482 patent/WO2008139065A2/fr not_active Ceased
  • 2008-04-07 CN CN200880011214A patent/CN101715511A/zh active Pending
  • 2008-04-07 JP JP2010502544A patent/JP5155387B2/ja not_active Expired - Fee Related
  • 2008-04-07 US US12/595,137 patent/US8327821B2/en not_active Expired - Fee Related
  • 2008-04-07 EP EP08787921A patent/EP2137391A2/de not_active Withdrawn

Non-Patent Citations (1)

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