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
  • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
  • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
  • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
• • 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
  • F02M45/04—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 with a small initial part, e.g. initial part for partial load and initial and main part for full load
  • F02M45/08—Injectors peculiar thereto
• • 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
  • F02M57/00—Fuel-injectors combined or associated with other devices
  • F02M57/02—Injectors structurally combined with fuel-injection pumps
  • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
  • F02M57/023—Injectors structurally combined with fuel-injection pumps characterised by the pump drive mechanical
• • 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
  • F02M2200/40—Fuel-injection apparatus with fuel accumulators, e.g. a fuel injector having an integrated fuel accumulator

Definitions

• the invention relates to a fuel injection system for an internal combustion engine.
• the fuel is sprayed directly inside the combustion chamber of the petrol or diesel type engine in particular. It is therefore inside this combustion chamber that the mixture takes place between the fuel and the air, which plays the role of oxidizer.
• the pump injectors make it possible to inject fuel only during a main injection phase, corresponding to the injection preceding the explosion in the combustion chamber.
• This injection is obtained by means of a cam profile which makes it possible to move a piston inside the injector so as to compress the fuel just before the main injection. The compressed fuel is then injected into the combustion chamber.
• this type of injection system does not allow fuel to be injected outside an active area of the cam.
• unburnt fuel can be brought up to the level of a particulate filter located in the exhaust line, which has the effect of cleaning and regenerating it. .
• this type of injector allowing a second injection phase currently requires complex common rail injection systems and provided with an internal capacity intended to allow injection pilots to be produced, such as in particular described in the document US 4,913,113.
• the fuel is not compressed, and their function is limited to injecting the fuel inside the combustion chamber.
• a common rail system allows great flexibility in multiple injection.
• it does not allow the forms of instantaneous injection flow rate to be achieved, and to reach the level of injection pressures that it is possible to obtain with a conventional pump injector system.
• each injector it is necessary to connect to a high pressure manifold which thus comprises a large number of connections which are as many potential leakage zones.
• injection systems with pump injectors controlled by cams, the active area of which comprises a succession of hollows and bumps. It is then possible to inject fuel at different times for post-treatment needs or new combustion concepts, such as the HCCI meaning "Homogeneous Charge Compression Ignition".
• the needs related to the mechanical strength and the constraints of manufacturing the cam limit the characteristics of the main active area of the cam. They also affect the filling of the injector due to an increase in the recoil speed of the injector plunger.
• the position of the secondary injection is dependent on the design of the cam, which limits flexibility and does not allow the injection phases to be varied independently.
• hybrid systems have also been designed which combine both pump injectors and common rail.
• a common rail conveying fuel under pressure is connected to the supply of the pump injectors.
• this type of system is very complex and expensive, and it requires significant qualification to carry out its repair when a fault is detected in the injection system.
• it does not provide a satisfactory solution for carrying out secondary injection phases at low cost and with high reliability.
• the object of the invention is to provide a system adaptive to current injection systems and which is also reliable and flexible.
• Such a system must also make it possible to inject fuel under pressure inside an engine, whatever the position of the piston without limitation in terms of the quantity injected, and with very high fuel pressures.
• the invention therefore relates to a pump injector intended to compress fuel, then to inject it inside the combustion chamber of a cylinder of a heat engine.
• This type of injector can inject fuel during a main injection phase by means of a needle whose movement is controlled by a first solenoid valve. In this way, the fuel contained inside the internal volume of the injector escapes through at least one orifice in the combustion chamber of the cylinder on which it is mounted.
• the injector is characterized in that it comprises: • a capacity, intended to store a volume of fuel under pressure; • a second solenoid valve capable of putting said capacity into communication with the internal volume of the injector to allow a secondary injection phase.
• This second solenoid valve is activated concomitantly with the first solenoid valve during the two main and secondary injection phases.
• each injector has an area where pressurized fuel can be stored, then evacuated to allow a secondary injection phase which may occur early, or late with respect to the main injection phase at n ' any time in the cycle.
• This capacity is placed in communication with the internal volume of the injector by means of a second solenoid valve, which, when it is simultaneously activated with the first solenoid valve, makes it possible to carry out several injections and in particular a main injection phase and a secondary phase.
• the pump injector comprises, at a filling pipe intended to allow the filling of the fuel capacity under pressure, a non-return filling means able to allow the flow of fuel in one direction, from internal volume to capacity.
• the capacity is linked to the internal volume of the injector by means of a filling line in which the pressurized fuel circulates in only one direction.
• a non-return means such as a valve, is fitted inside this pipe in order to authorize the circulation of the fuel only in the direction of the internal volume towards the capacity.
• the circulation of fuel inside this pipe does not take place until the main injection phase has ended. This is obtained by deactivating the first solenoid valve while keeping the second active.
• the filling non-return means may comprise a member for allowing the flow of fuel when the pressure difference between the internal volume and the capacity exceeds a predetermined threshold value.
• this elastic means can be calibrated at a pressure which is higher than that present in the injector during the main injection phase.
• the dead volume internal to the injector is not increased compared to a standard injector and the yield is identical.
• the elastic means acts as a pressure limiter.
• the injector comprises, at an injection pipe intended to make the capacity communicate with the internal volume, a non-return injection means capable of allowing the flow of fuel in one direction, of capacity to internal volume.
• the pressurized fuel is evacuated from the capacity when an injection is to be carried out, at a specific injection pipe, which allows the fuel to circulate only in one direction, and more precisely in the sense of capacity towards the internal volume of the injector.
• This circulation is carried out once the capacity is filled and the second solenoid valve activated since it then makes it possible to put the capacity in communication with the internal volume of the injector.
• Figure 1 is a block diagram of the pump injector, according to the invention
• Figures 2a to 2f are block diagrams showing the different stages of operation of the pump injector, according to the invention
• Figure 3 is a longitudinal section of the injector, according to the invention
• Figure 4 is a clrronogram to show the different states of the solenoid valves and the variables relating to the injection of fuel into the engine.
• the invention relates to a pump injector intended to compress and then inject fuel into the interior of the combustion chamber of an engine.
• the pump injector (1) makes it possible to compress fuel which is initially at a low pressure in a supply circuit (16). This compression is obtained by means of a cam (4) driven in rotation by the movement of the engine crankshaft directly or indirectly. This cam (4) then moves a piston (5) capable of compressing the fuel.
• a solenoid valve (2) then makes it possible to close or open the internal volume (3) of the injector (1), so as to allow the pressure inside its internal volume (3) to increase, or the fuel intake to be compressed.
• a second solenoid valve (6) makes it possible to lock the movement of a needle (7) whose movement makes it possible to release an orifice (9) allowing injection.
• Locking of the position of the needle (7) is obtained by making or not a pressure difference between the two ends of the needle (7).
• a return means (8) then makes it possible to return the needle (7) to its closed position.
• a capacity (11) allows fuel to be stored under pressure in order to allow injection in one or more secondary phases. In this way, it is then possible to inject at times very distant from the main injection, either in advance or with delay.
• the two solenoid valves (2, 6) are of the mono-stable type because they include an elastic return means to allow them to return to the deactivated state once the supply has been cut.
• These solenoid valves (2, 6) can in particular comprise two states and three channels. In this way, it is possible to set, by means of the solenoid valve (2) the internal volume (3) of the injector (1) either at the pressure of the supply circuit (16) or at the pressure P of the compressed fuel contained in the capacity (11).
• the solenoid valve (6) either the two ends of the needle (7) are at the pressure contained in the internal volume (3) of the injector (l), or one end at the pressure contained in the internal volume (3) and the other at the pressure contained in the supply circuit (16).
• a filling line (15) comprises a non-return means (10), so as to allow circulation in this filling line (15) only in one direction, namely in the direction of the internal volume (3) up to capacity (11).
• a second non-return means (12) is attached to an injection pipe (14) so as to also allow the circulation of the fuel under pressure in only one direction, namely the direction of the capacity (11) towards the internal volume (3) of the injector (1).
• the non-return means (10) comprises a member (13) which is in the form of an elastic member of the spring type. In this way, the circulation of fuel inside this filling pipe (15) is only possible when the pressure difference between the two orifices of the non-return valve (10) exceeds a predetermined threshold value.
• this solenoid valve (6) allows to put one side of the needle (7) to the pressure of the fuel contained in the supply circuit (16), and therefore, when the pressure P of the fuel contained in the internal volume (3) is greater than the pressure exerted by the return spring (8), the needle (7) moves and leaves orifices (9) injecting the fuel into the combustion chamber of the corresponding cylinder.
• FIG. 2d corresponding to the phase starting at time t3 in FIG. 4, once the main injection has ended, it is possible to store fuel under pressure within a capacity (11 ).
• the solenoid valve (6) is deactivated, which makes it possible to put the two sides of the needle (7) at the same pressure P and consequently, this causes it to descend under the effect of the return spring ( 8). Fuel contained in the internal volume (3) is then able to flow inside a filling pipe (15) of the capacity (11).
• this pipe (15) has a non-return means (10) to let the fuel circulate in only one direction. Indeed, the only direction of circulation inside this pipe (15) is then that going from the internal volume (3) of the injector (1) towards the capacity (11).
• this non-return means (10) may comprise an elastic member (13) so as to allow the circulation of the fuel in this line (15) only when the pressure P of the fuel exceeds a predetermined threshold value.
• the solenoid valve (2) if one wishes to carry out an injection during a secondary phase, the solenoid valve (2) must then be activated simultaneously with the solenoid valve (6), which makes it possible to release the needle (7) by putting one of its ends to the pressure of the fuel contained in the supply circuit (16), while the other end is to the pressure P of the fuel initially compressed and stored in the capacity (11), except for pressure drops.
• the pump injector can be assembled from a number of sections (20, 21, 22, 23, 24, 25), to facilitate its design and the realization of the various pipes present inside its internal volume (3).
• the capacity (11) can, for example, straddle several sections (24, 25) and be produced by a recess opening into several sections.
• the anti-return means (10, 12) are obtained by means of balls, capable of moving inside a housing. The displacement of these balls makes it possible to obstruct or not an orifice and then prohibits the circulation of fuel inside this pipe.
• the fuel injection is represented by the curve D9, corresponding to the fuel flow circulating at the level of the orifices (9).
• a pump injector according to the invention has multiple advantages, in particular: • it makes it possible to inject fuel outside the main injection phase at any time during the cycle; • it enables very high pressure fuel to be injected using a high reliability solution; • it does not require any modification of the architecture of the engine and can directly replace existing devices, which is not negligible in terms of cost.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Fuel-Injection Apparatus (AREA)
• Percussion Or Vibration Massage (AREA)
• Jet Pumps And Other Pumps (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=34947290

Family Applications (1)

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Cited By (1)

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• 2004
  • 2004-06-04 FR FR0451112A patent/FR2871197B1/fr not_active Expired - Fee Related
• 2005
  • 2005-05-27 WO PCT/FR2005/050382 patent/WO2005124144A1/fr not_active Application Discontinuation
  • 2005-05-27 DE DE602005014469T patent/DE602005014469D1/de active Active
  • 2005-05-27 EP EP05766704A patent/EP1751421B1/de not_active Not-in-force
  • 2005-05-27 AT AT05766704T patent/ATE431499T1/de not_active IP Right Cessation

Non-Patent Citations (1)

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