Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
  • F02M63/0012—Valves
  • F02M63/0014—Valves characterised by the valve actuating means
  • F02M63/0028—Valves characterised by the valve actuating means hydraulic
  • F02M63/0029—Valves characterised by the valve actuating means hydraulic using a pilot valve controlling a hydraulic chamber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
  • F02M45/02—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts
  • F02M45/10—Other injectors with multiple-part delivery, e.g. with vibrating valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
  • F02M69/04—Injectors peculiar thereto
  • F02M69/041—Injectors peculiar thereto having vibrating means for atomizing the fuel, e.g. with sonic or ultrasonic vibrations
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
  • F02M2200/21—Fuel-injection apparatus with piezoelectric or magnetostrictive elements

Definitions

• the present invention relates to a fuel injector for an internal combustion engine, in particular Diesel intended in particular to be implemented in a motor vehicle
• a conventional internal combustion engine comprises at least one cylinder in which a piston slides between two extreme positions.
• the piston delimits with the cylinder and a cylinder head a combustion chamber.
• an injector serves to supply fuel. finely atomized to the combustion chamber of the internal combustion engine
• This injector 10 comprises a body 12 comprising a transducer 14 capable of generating vibrations in a longitudinal mode at ultrasonic frequencies.
• the transducer 14 ends in the lower part by a nozzle 16 in which the vibrations coming from the transducer 14 are amplified.
• the entire transducer 14 has a first internal cavity 18
• the first internal cavity 18 is intended to be filled with pressurized fuel To do this, the first cavity 18 is connected to a fuel supply port 20 adapted to be put into operation. communication with a fuel supply circuit under pressure (not shown)
• the first cavity 18 opens at the lower end 22 of the nozzle 16, also called the nose of the injector, through an injection port
• the injector 10 also comprises a rod 24, or needle, extending mainly along the axis yy '
• the rod 24 is housed axially movable inside the nozzle 16
• the lower end of the needle 24 has a head shutter 26 extending outside the nozzle 16
• This closure head 26 is adapted to come into contact with the inner surface of the nozzle 16 defining the injection orifice of the nozzle 16 so as to close the fuel injection port
• the other end of the rod is provided with a mass 28 elastically connected by a spring 30 to the body 12 of the injector 10
• the system 32 consisting of the mass 28 and the spring 30 is housed in a second cavity 34 formed in the rear part of the body 12 of the injector 10
• the stem assembly 24 and elastic spring 30, exerts a desired elastic return force for applying the closure head 26 of the rod 24 to the zone of the nozzle 16 surrounding the injection orifice
• the applied preload allows on the one hand the sealing of the injection orifice formed at the end of the nozzle 16 when the injector 10 is supplied with fuel with a given pressure and secondly the catch of possible wear in the contact zone of the closure head 26 of the rod 24 with the nozzle 16
• the mass 28 is fixed, for example, by screwing on the rod 24 so as to achieve a mechanical impedance break at the interface between the rod 24 and the mass 28.
• the value of the mass 28 and the rigidity of the spring 30 are chosen to form a system having a very large response time with respect to the excitation times of the transducer 14.
• the transducer 14 comprises an area consisting of a stack 36 of piezoelectric or magnetostrictive active components, which, respectively under the application of an electric or magnetic field, deform in thickness.
• This stack 36 is clamped between two other elements 37a, 37b made of an elastic material
• prestressing means such as a nut 38.
• the stack of several active components allows adding the thickness deformations generated by each of the active components, the deformation resulting from the total displacement of the stack of active components remaining below the elastic deformation limit of the prestressing means.
• the assembly 40 composed of the transducer 14 and the nozzle 16 is sized to resonate with the excitation frequency of the active components to amplify the longitudinal displacements up to the level of the lower end 22 of the nozzle 16.
• rod 24, initially closing the injection port by means of its closure head 26, deforms under the pulse that is provided when the nozzle 16 begins to oscillate. This deformation is distributed elastically over the entire length of the rod 24 and is reflected at the interface 42 between the rod 24 and the mass 28.
• the minimum opening time of the injector 10 is of the same order as the excitation period applied to the transducer which excitation can be done at a few tens of kilohertz typically 50 kHz, which allows a minimum opening time of the order of 20 ⁇ s This allows to deliver quantities of fuel of the order of one microliter for a short period of time
• the body 12 of the injector 10 is intended to be fixed to the upper end of the engine cylinder head by non-representative means
• injector 10 has indirect means for vibrating the stem longitudinally
• injectors comprising direct means for cyclically vibrating the rod are also known.
• An injector comprising a stack of piezoelectric ceramics or an magnetostrictive rod mounted directly in the body of the rod and which excites the rod so as to generate elastic deformations of the rod
• the rod In the two cases of excitation, direct or indirect, of the rod of the injector, the rod is embedded at one end in a mass
• the role of this mass is to realize a break of impedance so that the waves of deformation propagating in the rod are reflected at the border between the rod and the mass
• the injector 10 is of the outgoing needle type
• the injectors of the incoming needle type In the case of an injector of the incoming needle type, the rod is plated, at rest, on the inner face of the lower end of the nozzle under the effect of a spring The spring is mounted in the second cavity is thus ensured sealing of the injection port
• the rod is placed in longitudinal vibration The end of the rod then oscillates between its closed position of the injection orifice and an open position of this injection orifice
• the spring exerts on the rod either a pulling force (in the case of an outgoing needle type injector) or a compressive force (in the case of an injector of the incoming needle type)
• the dimensions of the injector are imposed by the space available on the engine and in the direct environment of the engine
• the volume of the injector being imposed, the bulk of the mass + spring system ensuring an impedance break sufficient and a satisfactory sealing force at the level of the injection orifice may correspond to a spring of a stiffness such that the spring mass system has a resonant frequency lying in the excitation range imposed by the vibrations of the motor. its resonant frequency causes an opening of the injector in a chaotic manner
• the object of the invention is to provide a fuel injector not having the aforementioned defects and suitable, in particular, to ensure a fuel injection in the form of fine droplets better controlled relative to the constraints of the environment of the injector.
• a fuel injector for an internal combustion engine particularly of the incoming needle type or of the outgoing needle type, comprising
• an injector body forming in particular a nozzle terminated by an injection orifice
• said sealing means comprising a vibrating rod terminating in a closure head of said injection orifice
• said injector comprises selectively activatable locking means of said rod relative to said body.
• the rod does not oscillate and, therefore, any risk of resonance of the rod at vibration frequencies of the motor is spaced, which ensures the control of the injection
• the locking means of the rod can be disabled
• the return means of the closure means make it possible to reposition the closure means in a position where the stem is relieved of the stresses due to the differential expansion of the rod relative to the body
• said selectively activatable locking means of said rod are able to cooperate with said rod and / or with a mass to which said rod is fixed so as to achieve a mechanical impedance break
• said locking means comprise a piston capable of sliding in a direction substantially perpendicular to said rod
• the fuel injector according to the invention comprises a hydraulic chamber for controlling the movement of said piston.
• said hydraulic control chamber comprises at least one fuel inlet which is in fluid communication with a fuel supply orifice of said injector
• said hydraulic control chamber further comprises at least one fuel outlet orifice, the total section of said at least one inlet orifice being less than the total section of said at least one outlet orifice.
• the fuel injector according to the invention comprises means for controlling the filling or emptying of said hydraulic control chamber of the magnetostrictive or electromagnetic or electrostrictive or piezoelectric type.
• said means for cyclically vibrating said rod and / or said nozzle are of the piezoelectric and / or magnetostrictive and / or electromagnetic type.
• said means for cyclically vibrating said rod and / or said nozzle are able to cause elastic deformations of said rod and / or said nozzle at ultrasonic frequencies.
• said means for cyclically vibrating said rod and / or said nozzle are mounted integral with said body and / or said rod.
• FIG. 1 represents a view in longitudinal section of an injector according to a first embodiment of the invention
• FIG. 2 represents a sectional view along the sectional plane A-A of the injector of FIG. 1;
• FIG. 3 represents a view in longitudinal section of an injector according to a second embodiment of the invention
• FIG. 4 represents a view in longitudinal section of an injector according to a third embodiment of the invention.
• FIG. 5 represents a view in longitudinal section of an injector according to a fourth embodiment of the invention.
• FIG. 6 represents a view in longitudinal section of an injector according to the state of the art
• a first embodiment of the injector 44 according to the invention is shown in longitudinal section in FIG.
• the injector 44 comprises means for blocking the mass 28 relative to the body 12 which are selectively activatable
• locking means comprise a piston 46 mounted free in translation relative to the body 12 of the injector 44 along an axis xx 'substantially perpendicular to the axis yy' of the rod 24.
• the locking means also comprise a support piece 48 adapted to cooperate with the piston 46 so as to block the mass 28 in translation along the axis yy '
• the piston 46 and / or the support piece 48 have a bearing face on the mass 28 of shape complementary to the mass 28.
• the mass 28 being, in this case, cylindrical
• the piston 46 and the support piece 48 has a bearing face adapted to cooperate with the mass 28 of concave shape, substantially
• the locking force exerted by the locking means is optimized for a given pressure.
• the support piece 48 is made of hard steel
• the piston 46 and the support piece 48 are substantially of the same height as the mass 28 so as to ensure a contact surface between the piston, the mass and the largest possible support piece
• the injector 44 In order to control the translation of the piston 46, the injector 44 according to the first embodiment of the invention has a hydraulic control chamber 50 This hydraulic control chamber 50 is delimited on the one hand by the body 12 of the injector 44 and secondly by the piston 46
• the hydraulic control chamber 50 has a fuel inlet port 52
• a fuel bypass conduit 53 opens through this fuel inlet port 52
• the bypass conduit 53 opens on the other hand in the supply duct 54 of the injector 44, preferably between the supply orifice 20 and the first cavity 18
• the hydraulic control chamber 50 furthermore has a hydraulic fluid outlet orifice 56 whose section is, preferably, greater than the section of the inlet orifice 52.
• This outlet orifice 56 is connected to the second cavity 34.
• the second cavity 34 is closed by a plug 58
• This plug 58 has a low pressure fuel outlet pipe 60
• the injector 44 comprises a valve 62 in this case of the electric control type, preferably of the magnetostrictive, electromagnetic or electrostrictive type This valve 62 is able to cut off the fluid communication between the hydraulic control chamber 50 and the second cavity 34
• valve 62 When the valve 62 is electrically powered, it opens The fuel is then discharged to the second cavity 34 The pressure in the hydraulic control chamber 50 then drops and the piston 46 reduces its grip The mass 28 is released and the voltage in the rod 24 takes the value that the spring 30 imposes on him
• This command to open the valve 62 is done periodically (for example every minute) and for very short periods, of the order of a few hundred milliseconds to allow the voltage in the rod 24 to return to the imposed value. by the spring 30, and to eliminate overvoltages which may appear in the rod 24 because of the differential expansions between the body 12 of the injector 44 and the rod 24
• the opening of this valve 62 may, for example, be realized between two successive injections
• the valve 62 preferably offers a small pressure drop so that the pressure in the hydraulic control chamber 48 drops rapidly.
• the bypass duct 53 is sufficiently resistant to the rise in pressure in the hydraulic control chamber 50. the hydraulic control chamber 50 does not have time to rise to oppose the release of the mass 28
• valve 62 When the valve 62 is no longer powered, it closes so as to block the fluid communication between the hydraulic control chamber 50 and the second cavity 34. The pressure in the hydraulic control chamber 50 then increases. The piston 46 is then pressed against the mass 28 against the support piece 48 so as to block the mass 28, as shown in FIG. 2 Immediately after locking, the force in the rod 24 is at the value that the spring 30 imposes, the rod 24 being rid of additional efforts that may have been created following differential expansions
• FIG. 3 presents a second embodiment of the injector according to the invention.
• the injector 66 shown in FIG. 3 differs from the injector 44 according to the first embodiment of the invention in that it is an injector of the incoming needle type.
• the rod 24 is plated, at rest, on the inner face of the lower end 22 of the nozzle 16 under the effect of the spring 30 which is mounted in the second cavity 34
• FIG. 4 presents a third embodiment of the injector according to the invention.
• the injector 70 shown in FIG. 4 differs from the injector 44 according to the first embodiment in that it does not have a stack 36 of active components, for example piezoelectric or magnetostrictive, mounted on the body of the 'injector.
• a stack 72 of active components able to deform under the effect of an electric or magnetic field, preferably piezoelectric or magnetostrictive components is mounted integral on the rod 24 so that the deformation of this stack 72 of active components directly causes the longitudinal vibration of the rod 24
• FIG. 5 presents a fourth embodiment of the injector according to the invention.
• the injector 74 shown in FIG. 5 differs from the injector 66 according to the second embodiment in that it does not have a stack 36 of active components, for example piezoelectric or magnetostrictive, mounted on the body of the 'injector.
• a stack 72 of active components capable of deform under the effect of an electric current for example piezoelectric or magnetostrictive elements, is mounted integral on the rod 24 so that the deformation of this stack 72 of active components directly causes the longitudinal vibration of the rod 24
• the locking piston and the support piece can cooperate directly with the rod, the mass then possibly being removed.
• piston device 46 and support piece 48 has an advantageous embodiment of selectively activatable locking means, these elements can be replaced by any selectively activatable device that effectively makes it possible to block the mass and / or or rod
• any selectively activatable device that effectively makes it possible to block the mass and / or or rod

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 2005
  • 2005-12-19 FR FR0512894A patent/FR2895031B1/fr not_active Expired - Fee Related
• 2006
  • 2006-11-29 AT AT06842058T patent/ATE507391T1/de not_active IP Right Cessation
  • 2006-11-29 EP EP06842058A patent/EP1963665B1/de not_active Ceased
  • 2006-11-29 DE DE602006021621T patent/DE602006021621D1/de active Active
  • 2006-11-29 JP JP2008546536A patent/JP2009520153A/ja not_active Ceased
  • 2006-11-29 WO PCT/FR2006/051247 patent/WO2007071863A1/fr not_active Ceased
  • 2006-11-29 US US12/097,310 patent/US8038080B2/en not_active Expired - Fee Related

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