EP1402174B1 - Fuel injection device for an internal combustion engine - Google Patents

Fuel injection device for an internal combustion engine Download PDF

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Publication number
EP1402174B1
EP1402174B1 EP02742765A EP02742765A EP1402174B1 EP 1402174 B1 EP1402174 B1 EP 1402174B1 EP 02742765 A EP02742765 A EP 02742765A EP 02742765 A EP02742765 A EP 02742765A EP 1402174 B1 EP1402174 B1 EP 1402174B1
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EP
European Patent Office
Prior art keywords
pump
fuel injection
injection valve
pressure
pump working
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP02742765A
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German (de)
French (fr)
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EP1402174A1 (en
Inventor
Herbert Strahberger
Serge Moling
Peter Voigt
Alain Amblard
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication date
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Publication of EP1402174A1 publication Critical patent/EP1402174A1/en
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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M57/00Fuel-injectors combined or associated with other devices
    • F02M57/02Injectors structurally combined with fuel-injection pumps
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M45/00Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • F02M45/02Fuel-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
    • F02M45/04Fuel-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
    • F02M45/08Injectors peculiar thereto
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20Varying fuel delivery in quantity or timing
    • F02M59/36Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
    • F02M59/366Valves being actuated electrically
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/20Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
    • F02M61/205Means specially adapted for varying the spring tension or assisting the spring force to close the injection-valve, e.g. with damping of valve lift
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02BINTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00Engines characterised by air compression and subsequent fuel addition
    • F02B3/06Engines characterised by air compression and subsequent fuel addition with compression ignition
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/50Arrangements of springs for valves used in fuel injectors or fuel injection pumps
    • F02M2200/505Adjusting spring tension by sliding spring seats

Definitions

  • the invention relates to a fuel injection device for an internal combustion engine according to the preamble of claim 1.
  • Such a fuel injection device is known from DE 39 00 763 A1.
  • This fuel injection device has a high-pressure fuel pump and a fuel injection valve for a cylinder of the internal combustion engine.
  • the high-pressure fuel pump has a driven by the internal combustion engine, a pump working space limiting pump piston, wherein a connection of the pump working chamber is controlled by a discharge valve with an electrically controlled valve.
  • the fuel injection valve has an injection valve member through which at least one injection port is controlled and which is movable in an opening direction by the pressure prevailing in a pressure chamber connected to the pump chamber pressure against the force of a closing spring arranged in a spring chamber.
  • the closing spring is supported on the one hand at least indirectly on the injection valve member and on the other hand at least indirectly on an evasive piston.
  • the bypass piston limits on its side facing away from the closing spring a connected to the pump working chamber via a throttle point antechamber and is thus acted upon by the pressure prevailing in the pump working chamber and movable against the force of the closing spring in a lifting movement.
  • the bypass piston is movable from a starting position at low pressure in the pressure chamber into a storage space.
  • the pressure chamber of the fuel injection valve is over a Canal with the anteroom and connected via this indirectly with the pump working space.
  • the connection of the pressure chamber with the pump working space is thus also via the throttle point, the dimensioning of the throttle point must be chosen as a compromise between the required for the function of the bypass piston sizing and the required for the function of the fuel injection valve sizing.
  • US-A-4572433 also discloses a fuel injector for an internal combustion engine having a high-pressure fuel pump and a fuel injection valve for a cylinder of the internal combustion engine.
  • the high-pressure fuel pump has a driven by the internal combustion engine in a lifting movement, a pump working space limiting pump piston.
  • the fuel injection valve has an injection valve member through which at least one injection port is controlled and which is movable in an opening direction by the pressure prevailing in a pressure chamber connected to the pump chamber pressure against the force of a closing spring arranged in a spring chamber.
  • a first throttle point is arranged in the connection of the pressure chamber of the fuel injection valve with the pump working space.
  • the injection valve member is additionally acted upon by the pressure prevailing in a control pressure chamber in the closing direction.
  • the control pressure chamber is connected via a second throttle point with the connection between the pressure chamber of the fuel injection valve and the pump working space downstream of the first throttle point and thus also connected to the pump working space.
  • both throttles are effective, which are arranged in series.
  • An independent optimization of the two throttle points is thus not possible because the first throttle point is effective both in the connection of the pressure chamber with the pump working chamber and in the connection of the control pressure chamber with the pump working space.
  • the fuel injection device with the features of claim 1 has the advantage that the first and the at least one second orifice can be selected independently of each other optimally for the respective function by the direct connection of the pressure chamber of the fuel injection valve with the pump working chamber via the at least one second orifice ,
  • FIG. 1 An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description.
  • the figure shows a fuel injection device for an internal combustion engine in a longitudinal section.
  • a fuel injection device for an internal combustion engine of a motor vehicle is shown.
  • the internal combustion engine has one or more cylinders, wherein a fuel injection device with a high-pressure fuel pump 10 and a fuel injection valve 12 is provided for each cylinder.
  • the high-pressure fuel pump 10 and the fuel injection valve 12 are combined to form a so-called pump-nozzle unit.
  • the high-pressure fuel pump 10 has a pump body 14, in which in a cylinder bore 16, a pump piston 18 is guided tightly, which is driven by a cam of a camshaft of the internal combustion engine against the force of a return spring 19 in a lifting movement.
  • the pump piston 18 defines in the cylinder bore 16 a pump working chamber 22, in which the delivery stroke of the pump piston 18 compresses fuel under high pressure.
  • the pump working chamber 22 is supplied with fuel from a fuel reservoir 24 during the suction stroke of the pump piston 18, for example by means of a feed pump.
  • the pump working space 22 has a connection with a discharge space, for example, can serve as the fuel tank 24, and which is controlled by an electrically controlled valve 23.
  • the electrically controlled valve 23 is connected to a control device 25.
  • the fuel injection valve 12 has a valve body 26 which is explained in more detail below, and which is connected to the pump body 14.
  • an injection valve member 28 is guided longitudinally displaceably in a bore 30.
  • the bore 30 extends at least approximately parallel to the cylinder 16 of the pump body 14, but may also extend inclined thereto.
  • the valve body 26 has at its the Combustion chamber of the cylinder of the engine facing end portion at least one, preferably a plurality of injection openings 32.
  • the injection valve member 28 has at its end region facing the combustion chamber, for example, a conical sealing surface 34 which cooperates with a in the valve body 26 in the end region facing the combustion chamber, for example, also approximately conical valve seat 36, from or after the discharge the injection ports 32.
  • annular space 38 is present between the injection valve member 28 and the bore 30 toward the valve seat 36, which merges in its end region remote from the valve seat 36 by a radial widening of the bore 30 into a pressure chamber 40 surrounding the injection valve member 28.
  • the injection valve member 28 has at the level of the pressure chamber 40 by a cross-sectional reduction on the valve seat 36 facing the pressure shoulder 42.
  • a prestressed closing spring 44 At the end remote from the combustion chamber of the injection valve member 28 engages a prestressed closing spring 44, through which the injection valve member 28 is pressed to the valve seat 36.
  • the closing spring 44 is arranged in a spring chamber 46, which adjoins the bore 30.
  • the spring chamber 46 is preferably connected to a relief space, for example the fuel tank 24.
  • the pressure chamber 40 is connected to the pump working chamber 22 via a channel 48 extending through the valve body 26.
  • the closing spring 44 is supported, on the one hand, at least indirectly, for example via a spring plate, on the injection valve member 28 and, on the other hand, at least indirectly, for example also via a spring plate 51, on a bypass piston 50.
  • the bypass piston 50 is guided in a bore 80 of a housing part 81 and has at its end of the closing spring 44 facing a shaft portion 52 which through a connecting hole 53 in a partition wall 54 of the housing part 81 passes between the spring chamber 46 and a subsequent thereto in the housing part 81 storage space 55.
  • the spring plate 51 is supported.
  • the connecting bore 53 has a smaller diameter than the spring chamber 46 and the storage space 55.
  • the bypass piston 50 has in the storage chamber 55 a region 56 with a larger diameter than the connecting bore 53, so that a stroke movement of the bypass piston 50 in the spring chamber 46 thereby limited is that the area 56 of the bypass piston 50 comes to the partition wall 54 as a stop to the plant.
  • the bypass piston 50 is guided with its portion 56 in the bore 80 with respect to the connecting hole 53 correspondingly larger diameter.
  • the spring chamber 46 is formed as a bore in a housing part 82, which forms part of the valve body 26.
  • the channel 48 extends through the housing part 82 offset from the spring chamber 46 approximately parallel to this.
  • the bypass piston 50 has the bore 58 toward the region 56 then a sealing surface 60, which is formed for example approximately conical.
  • the sealing surface 60 cooperates with the mouth of the bore 58 in the storage space 55 on the housing part 81 as a seat, which may also be formed approximately conical.
  • the bypass piston 50 has a shaft 62 protruding into the bore 58, the diameter of which is smaller than that of the region 56.
  • the shaft 62 then initially has a substantially smaller diameter on the sealing surface 60 than the bore 58 and, toward its free end, subsequently a shaft region 64 with a diameter which is only slightly smaller than that Diameter of the bore 58.
  • the shaft portion 64 may have at its periphery one or more flats 65 through which openings are formed between the shaft portion 64 and the bore 58 through which fuel may enter the storage space 55.
  • an intermediate disc 83 is arranged, in which a bore 84 is formed, through which the bore 58 is connected in the housing part 81 with the pump working chamber 22.
  • the bore 84 represents a first throttle point, via which the bore 58 is connected to the pump working chamber 22.
  • the bypass piston 50 delimits in the bore 58 to the intermediate disc 83 toward an antechamber 85, which is connected via the first throttle point 84 to the pump working chamber 22.
  • the deflecting piston 50 When the deflecting piston 50 is in an initial position in which it rests with its sealing surface 60 on the sealing seat at the mouth of the bore 58, the storage space 55 is separated from the antechamber 85 and thus from the pump working chamber 22. In the initial position of the bypass piston 50, the pressure prevailing in the pump working space 22 acts on the end face of the shaft portion 64 and through the openings between the shaft portion 64 and the bore 58 on the sealing surface 60 of the accumulator piston 50 corresponding to the diameter of the bore 58.
  • the bypass piston 50 is through held the force of the closing spring 44 against the pressure prevailing in the pump chamber 22 and thus in the antechamber 85 pressure in its initial position when the force exerted by the pressure in the pump chamber 22 on the accumulator piston 50 force is less than the force of the closing spring 44th
  • a further housing part 86 is arranged on the housing part 82 as part of the valve body 26, which has a bore 87 through which an end region of the injection valve member 28 passes and protrudes into the spring chamber 46.
  • the injection valve member 28 is supported with its end region in the spring chamber 46 via a spring plate 88 on the closing spring 44.
  • the end portion of the injection valve member 28 has a smaller diameter than the guided in the bore 30 area.
  • the bore 30, the pressure chamber 40 and the annular space 38, at the lower end of the valve seat 34 and the injection ports 32 are arranged in a part of the valve body 26 forming valve housing 89 are formed.
  • an intermediate disc 90 is arranged with a small thickness.
  • the washer 90 has a bore 91 through which the end portion of the injection valve member 28 passes.
  • the channel 48 extends from the pressure chamber 40 through the valve housing 89, the washer 90, the housing part 86, the housing part 82 and the washer 83.
  • the washer 83 has on its side facing the pump body 14 a groove 92, the pump working space 22 out is open and into which the channel 48 opens.
  • the groove 92 For example, it may extend approximately radially to the cylinder bore 16 and extends outwardly from the cylinder bore 16 to the region of the washer 83 in which the channel 48 passes therethrough.
  • the connection of the pressure chamber 40 of the fuel injection valve 12 with the pump working chamber 22 through the channel 48 thus takes place directly bypassing the vestibule 85, which is limited by the bypass piston 50 in the bore 58 to the washer 83 out.
  • a second throttle body 93 is provided in the pressure chamber 48 with the pump working chamber 22 connecting channel 48.
  • the second throttle body 93 By the second throttle body 93, a damping of pressure oscillations in the channel 48 can be achieved.
  • the second throttle body 93 can be formed by a targeted reduction of the cross section of the channel 48. It may be provided in particular that the channel 40 in the intermediate disc 83 and / or in the intermediate disc 90 is formed to form the throttle body 93 as a throttle bore with a defined cross-section.
  • the first throttle body 84 and the second throttle body 93 can be selected independently of each other for the respective function optimally.
  • the fuel injection valve 12 and the high-pressure fuel pump 10 are connected to each other by means of a clamping sleeve 94.
  • the clamping sleeve 94 engages over the valve housing 89 and is screwed into a threaded bore 95 in the pump body 14.
  • the intermediate disc 83, the housing parts 81, 82, 86 and the intermediate disc 90 are clamped between the valve housing 89 and the pump body 14.
  • the function of the fuel injector will be explained below.
  • the pump working space 22 is filled with fuel during the suction stroke of the pump piston 18.
  • the control valve 23 is initially opened, so that no high pressure can build up in the pump working chamber 22.
  • the control valve 23 is closed by the control means 25, so that the pump working space 22 is separated from the fuel tank 24 and builds up in this high pressure.
  • the injection valve member 28 moves in the opening direction 29 and outputs the at least one injection port 32 free, is injected through the fuel into the combustion chamber of the cylinder.
  • the bypass piston 50 is in this case in its starting position.
  • the pressure in the pump working chamber 22 subsequently increases in accordance with the profile of the pump piston 18 driving cam further.
  • bypass piston 50 executes its evasive stroke movement and moves into the reservoir 55 In this case, a pressure drop in the pump working chamber 22 is caused and also increases the bias of the closing spring 44, which is supported on the shaft portion 52 on the accumulator piston 50.
  • the Fuel injection valve 12 is open only for a short period of time and it is injected only a small amount of fuel as a pilot injection into the combustion chamber.
  • the injected amount of fuel is essentially determined by the opening pressure of the bypass piston 50, that is the pressure in the pump working chamber 22 and in the anteroom 85, in which the bypass piston 50 begins its evasive stroke movement.
  • the opening stroke of the injection valve member 28 during the pilot injection may be hydraulically limited by a damper.
  • a damping unit is known from DE 39 00 762 A1 and the corresponding US-5, 125, 580 and DE 39 00 763 A1 and the corresponding US-5,125,581.
  • the lifting movement of the bypass piston 50 can also be damped by means of a damping device, as described in DE 39 00 762 A1, DE 39 00 763 A1, US 5,125,580 and US 5,125,581.
  • the pressure in the pump chamber 22 continues to increase according to the profile of the pump piston 18 driving cam, so that the force acting on the injection valve member 28 compressive force in the opening direction 29 increases again and 44 exceeds the increased closing force due to the increased bias of the closing spring, so that the fuel injection valve 12 opens again.
  • a larger amount of fuel is injected over a longer period of time than during the pilot injection.
  • the time duration and the amount of fuel injected during this main injection are determined by the time at which the control valve 23 is opened again by the control device 25.
  • the pump working chamber 22 is again connected to the fuel tank 24, so that this is relieved and the fuel injection valve 12 closes.
  • the bypass piston 50 with the shaft part 52 is moved back into its initial position by the force of the closing spring 44.
  • the time offset between the pilot injection and the main injection is determined mainly by the deflection stroke of the bypass piston 50.

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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)

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einer Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine nach der Gattung des Anspruchs 1.The invention relates to a fuel injection device for an internal combustion engine according to the preamble of claim 1.

Eine solche Kraftstoffeinspritzeinrichtung ist durch die DE 39 00 763 A1 bekannt. Diese Kraftstoffeinspritzeinrichtung weist eine Kraftstoffhochdruckpumpe und ein Kraftstoffeinspritzventil für einen Zylinder der Brennkraftmaschine auf. Die Kraftstoffhochdruckpumpe weist einen durch die Brennkraftmaschine angetriebenen, einen Pumpenarbeitsraum begrenzenden Pumpenkolben auf, wobei durch ein elektrisch gesteuertes Ventil eine Verbindung des Pumpenarbeitsraums mit einem Entlastungsraum gesteuert wird. Das Kraftstoffeinspritzventil weist ein Einspritzventilglied auf, durch das wenigstens eine Einspritzöffnung gesteuert wird und das durch den in einem mit dem Pumpenarbeitsraum verbundenen Druckraum herrschenden Druck gegen die Kraft einer in einem Federraum angeordneten Schließfeder in einer Öffnungsrichtung bewegbar ist. Die Schließfeder stützt sich einerseits zumindest mittelbar am Einspritzventilglied und andererseits zumindest mittelbar an einem Ausweichkolben ab. Der Ausweichkolben begrenzt auf seiner der Schließfeder abgewandten Seite einen mit dem Pumpenarbeitsraum über eine Drosselstelle verbundenen Vorraum und ist somit vom im Pumpenarbeitsraum herrschenden Druck beaufschlagt und gegen die Kraft der Schließfeder in einer Hubbewegung bewegbar. Der Ausweichkolben ist von einer Ausgangsstellung bei geringem Druck im Druckraum in einen Speicherraum bewegbar. Der Druckraum des Kraftstoffeinspritzventils ist über einen Kanal mit dem Vorraum und über diesen mittelbar mit dem Pumpenarbeitsraum verbunden. Die Verbindung des Druckraums mit dem Pumpenarbeitsraum erfolgt somit ebenfalls über die Drosselstelle, wobei die Dimensionierung der Drosselstelle als Kompromiß zwischen der für die Funktion des Ausweichkolbens erforderlichen Dimensionierung und der für die Funktion des Kraftstoffeinspritzventils erforderlichen Dimensionierung gewählt werden muß.Such a fuel injection device is known from DE 39 00 763 A1. This fuel injection device has a high-pressure fuel pump and a fuel injection valve for a cylinder of the internal combustion engine. The high-pressure fuel pump has a driven by the internal combustion engine, a pump working space limiting pump piston, wherein a connection of the pump working chamber is controlled by a discharge valve with an electrically controlled valve. The fuel injection valve has an injection valve member through which at least one injection port is controlled and which is movable in an opening direction by the pressure prevailing in a pressure chamber connected to the pump chamber pressure against the force of a closing spring arranged in a spring chamber. The closing spring is supported on the one hand at least indirectly on the injection valve member and on the other hand at least indirectly on an evasive piston. The bypass piston limits on its side facing away from the closing spring a connected to the pump working chamber via a throttle point antechamber and is thus acted upon by the pressure prevailing in the pump working chamber and movable against the force of the closing spring in a lifting movement. The bypass piston is movable from a starting position at low pressure in the pressure chamber into a storage space. The pressure chamber of the fuel injection valve is over a Canal with the anteroom and connected via this indirectly with the pump working space. The connection of the pressure chamber with the pump working space is thus also via the throttle point, the dimensioning of the throttle point must be chosen as a compromise between the required for the function of the bypass piston sizing and the required for the function of the fuel injection valve sizing.

Durch die US-A-4572433 ist außerdem eine Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine mit einer Kraftstoffhochdruckpumpe und einem Kraftstoffeinspritzventil für einen Zylinder der Brennkraftmaschine bekannt. Die Kraftstoffhochdruckpumpe weist einen durch die Brennkraftmaschine in einer Hubbewegung angetriebenen, einen Pumpenarbeitsraum begrenzenden Pumpenkolben auf. Das Kraftstoffeinspritzventil weist ein Einspritzventilglied auf, durch das wenigstens eine Einspritzöffnung gesteuert wird und das durch den in einem mit dem Pumpenarbeitsraum verbundenen Druckraum herrschenden Druck gegen die Kraft einer in einem Federraum angeordneten Schließfeder in einer Öffnungsrichtung bewegbar ist. In der Verbindung des Druckraums des Kraftstoffeinspritzventils mit dem Pumpenarbeitsraum ist eine erste Drosselstelle angeordnet. Das Einspritzventilglied ist zusätzlich von dem in einem Steuerdruckraum herrschenden Druck in Schließrichtung beaufschlagt. Der Steuerdruckraum ist über eine zweite Drosselstelle mit der Verbindung zwischen dem Druckraum des Kraftstoffeinspritzventils und dem Pumpenarbeitsraum stromabwärts nach der ersten Drosselstelle verbunden und somit ebenfalls mit dem Pumpenarbeitsraum verbunden. In der Verbindung des Steuerdruckraums mit dem Pumpenarbeitsraum sind somit beide Drosselstellen wirksam, die in Reihe angeordnet sind. Eine unabhängige Optimierung der beiden Drosselstellen ist somit nicht möglich, da die erste Drosselstelle sowohl in der Verbindung des Druckraums mit dem Pumpenarbeitsraum als auch in der Verbindung des Steuerdruckraums mit dem Pumpenarbeitsraum wirksam ist. Zur Steuerung der Kraftstoffeinspritzung wird durch ein elektrisch gesteuertes Ventil eine Verbindung des Steuerdruckraums mit einem Entlastungsbereich geöffnet bzw. geschlossen. Wenn das Steuerventil geschlossen ist, so herrscht im Steuerdruckraum Hochdruck, durch den das Kraftstoffeinspitzventil geschlossen gehalten wird. Wenn das Steuerventil geöffnet ist, so ist der Steuerdruckraum entlastet, so dass das Einspritzventilglied öffnen kann.US-A-4572433 also discloses a fuel injector for an internal combustion engine having a high-pressure fuel pump and a fuel injection valve for a cylinder of the internal combustion engine. The high-pressure fuel pump has a driven by the internal combustion engine in a lifting movement, a pump working space limiting pump piston. The fuel injection valve has an injection valve member through which at least one injection port is controlled and which is movable in an opening direction by the pressure prevailing in a pressure chamber connected to the pump chamber pressure against the force of a closing spring arranged in a spring chamber. In the connection of the pressure chamber of the fuel injection valve with the pump working space, a first throttle point is arranged. The injection valve member is additionally acted upon by the pressure prevailing in a control pressure chamber in the closing direction. The control pressure chamber is connected via a second throttle point with the connection between the pressure chamber of the fuel injection valve and the pump working space downstream of the first throttle point and thus also connected to the pump working space. In the connection of the control pressure chamber with the pump working space thus both throttles are effective, which are arranged in series. An independent optimization of the two throttle points is thus not possible because the first throttle point is effective both in the connection of the pressure chamber with the pump working chamber and in the connection of the control pressure chamber with the pump working space. To control the fuel injection, a connection of the control pressure chamber with a discharge region is opened or closed by an electrically controlled valve. When the control valve is closed, there is high pressure in the control pressure chamber, by which the fuel injection valve is kept closed. When the control valve is opened, the control pressure chamber is relieved, so that the injection valve member can open.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Kraftstoffeinspritzeinrichtung mit den Merkmalen gemäß Anspruch 1 hat demgegenüber den Vorteil, daß durch die direkte Verbindung des Druckraums des Kraftstoffeinspritzventils mit dem Pumpenarbeitsraum über die wenigstens eine zweite Drosselstelle die erste und die wenigstens eine zweite Drosselstelle unabhängig voneinander optimal für die jeweilige Funktion gewählt werden können.The fuel injection device according to the invention with the features of claim 1 has the advantage that the first and the at least one second orifice can be selected independently of each other optimally for the respective function by the direct connection of the pressure chamber of the fuel injection valve with the pump working chamber via the at least one second orifice ,

In den abhängigen Ansprüchen sind vorteilhafte Ausgestaltungen und Weiterbildungen der erfindungsgemäßen Kraftstoffeinspritzeinrichtung angegeben. Die Ausbildungen gemäß den Ansprüchen 2 bis 4 ermöglichen fertigungstechnisch einfache Anordnungen und Ausbildungen der Drosselstellen.In the dependent claims advantageous refinements and developments of the fuel injection device according to the invention are given. The embodiments according to claims 2 to 4 allow manufacturing technology simple arrangements and configurations of the throttle bodies.

Zeichnungdrawing

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. Die Figur zeigt eine Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine in einem Längsschnitt.An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description. The figure shows a fuel injection device for an internal combustion engine in a longitudinal section.

Beschreibung des AusführungsbeispielsDescription of the embodiment

In der Figur ist eine Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine eines Kraftfahrzeugs dargestellt. Die Brennkraftmaschine weist einen oder mehrere Zylinder auf, wobei für jeden Zylinder eine Kraftstoffeinspritzeinrichtung mit einer Kraftstoffhochdruckpumpe 10 und einem Kraftstoffeinspritzventil 12 vorgesehen ist. Die Kraftstoffhochdruckpumpe 10 und das Kraftstoffeinspritzventil 12 sind zu einer sogenannten Pumpe-Düse-Einheit zusammengefaßt. Die Kraftstoffhochdruckpumpe 10 weist einen Pumpenkörper 14 auf, in dem in einer Zylinderbohrung 16 ein Pumpenkolben 18 dicht geführt ist, der durch einen Nocken einer Nockenwelle der Brennkraftmaschine entgegen der Kraft einer Rückstellfeder 19 in einer Hubbewegung angetrieben wird. Der Pumpenkolben 18 begrenzt in der Zylinderbohrung 16 einen Pumpenarbeitsraum 22, in dem beim Förderhub des Pumpenkolbens 18 Kraftstoff unter Hochdruck verdichtet wird. Dem Pumpenarbeitsraum 22 wird beim Saughub des Pumpenkolbens 18 Kraftstoff aus einem Kraftstoffvorratsbehälter 24 zugeführt, beispielsweise mittels einer Förderpumpe. Der Pumpenarbeitsraum 22 weist eine Verbindung mit einem Entlastungsraum auf, als der beispielsweise der Kraftstoffvorratsbehälter 24 dienen kann, und die von einem elektrisch gesteuerten Ventil 23 gesteuert wird. Das elektrisch gesteuerte Ventil 23 ist mit einer Steuereinrichtung 25 verbunden.In the figure, a fuel injection device for an internal combustion engine of a motor vehicle is shown. The internal combustion engine has one or more cylinders, wherein a fuel injection device with a high-pressure fuel pump 10 and a fuel injection valve 12 is provided for each cylinder. The high-pressure fuel pump 10 and the fuel injection valve 12 are combined to form a so-called pump-nozzle unit. The high-pressure fuel pump 10 has a pump body 14, in which in a cylinder bore 16, a pump piston 18 is guided tightly, which is driven by a cam of a camshaft of the internal combustion engine against the force of a return spring 19 in a lifting movement. The pump piston 18 defines in the cylinder bore 16 a pump working chamber 22, in which the delivery stroke of the pump piston 18 compresses fuel under high pressure. The pump working chamber 22 is supplied with fuel from a fuel reservoir 24 during the suction stroke of the pump piston 18, for example by means of a feed pump. The pump working space 22 has a connection with a discharge space, for example, can serve as the fuel tank 24, and which is controlled by an electrically controlled valve 23. The electrically controlled valve 23 is connected to a control device 25.

Das Kraftstoffeinspritzventil 12 weist einen Ventilkörper 26 auf, der wie nachfolgend noch näher erläutert wird mehrteilig ausgebildet ist, und der mit dem Pumpenkörper 14 verbunden ist. Im Ventilkörper 26 ist in einer Bohrung 30 ein Einspritzventilglied 28 längsverschiebbar geführt. Die Bohrung 30 verläuft zumindest annähernd parallel zum Zylinder 16 des Pumpenkörpers 14, kann jedoch auch geneigt zu diesem verlaufen. Der Ventilkörper 26 weist an seinem dem Brennraum des Zylinders der Brennkraftmaschine zugewandten Endbereich wenigstens eine, vorzugsweise mehrere Einspritzöffnungen 32 auf. Das Einspritzventilglied 28 weist an seinem dem Brennraum zugewandten Endbereich eine beispielsweise etwa kegelförmige Dichtfläche 34 auf, die mit einem im Ventilkörper 26 in dessen dem Brennraum zugewandtem Endbereich ausgebildeten, beispielsweise ebenfalls etwa kegelförmigen Ventilsitz 36 zusammenwirkt, von dem oder nach dem die Einspritzöffnungen 32 abführen.The fuel injection valve 12 has a valve body 26 which is explained in more detail below, and which is connected to the pump body 14. In the valve body 26, an injection valve member 28 is guided longitudinally displaceably in a bore 30. The bore 30 extends at least approximately parallel to the cylinder 16 of the pump body 14, but may also extend inclined thereto. The valve body 26 has at its the Combustion chamber of the cylinder of the engine facing end portion at least one, preferably a plurality of injection openings 32. The injection valve member 28 has at its end region facing the combustion chamber, for example, a conical sealing surface 34 which cooperates with a in the valve body 26 in the end region facing the combustion chamber, for example, also approximately conical valve seat 36, from or after the discharge the injection ports 32.

Im Ventilkörper 26 ist zwischen dem Einspritzventilglied 28 und der Bohrung 30 zum Ventilsitz 36 hin ein Ringraum 38 vorhanden, der in seinem dem Ventilsitz 36 abgewandten Endbereich durch eine radiale Erweiterung der Bohrung 30 in einen das Einspritzventilglied 28 umgebenden Druckraum 40 übergeht. Das Einspritzventilglied 28 weist auf Höhe des Druckraums 40 durch eine Querschnittsverringerung eine zum Ventilsitz 36 weisende Druckschulter 42 auf. Am dem Brennraum abgewandten Ende des Einspritzventilglieds 28 greift eine vorgespannte Schließfeder 44 an, durch die das Einspritzventilglied 28 zum Ventilsitz 36 hin gedrückt wird. Die Schließfeder 44 ist in einem Federraum 46 angeordnet, der sich an die Bohrung 30 anschließt. Der Federraum 46 ist vorzugsweise mit einem Entlastungsraum, beispielsweise dem Kraftstoffvorratsbehälter 24, verbunden. Der Druckraum 40 ist über einen durch den Ventilkörper 26 verlaufenden Kanal 48 mit dem Pumpenarbeitsraum 22 verbunden.In the valve body 26, an annular space 38 is present between the injection valve member 28 and the bore 30 toward the valve seat 36, which merges in its end region remote from the valve seat 36 by a radial widening of the bore 30 into a pressure chamber 40 surrounding the injection valve member 28. The injection valve member 28 has at the level of the pressure chamber 40 by a cross-sectional reduction on the valve seat 36 facing the pressure shoulder 42. At the end remote from the combustion chamber of the injection valve member 28 engages a prestressed closing spring 44, through which the injection valve member 28 is pressed to the valve seat 36. The closing spring 44 is arranged in a spring chamber 46, which adjoins the bore 30. The spring chamber 46 is preferably connected to a relief space, for example the fuel tank 24. The pressure chamber 40 is connected to the pump working chamber 22 via a channel 48 extending through the valve body 26.

Die Schließfeder 44 stützt sich einerseits zumindest mittelbar, beispielsweise über einen Federteller, am Einspritzventilglied 28 und andererseits zumindest mittelbar, beispielsweise ebenfalls über einen Federteller 51, an einem Ausweichkolben 50 ab. Der Ausweichkolben 50 ist in einer Bohrung 80 eines Gehäuseteils 81 geführt und weist an seinem der Schließfeder 44 zugewandten Endbereich einen Schaftteil 52 auf, der durch eine Verbindungsbohrung 53 in einer Trennwand 54 des Gehäuseteils 81 zwischen dem Federraum 46 und einem an diesen im Gehäuseteil 81 anschließenden Speicherraum 55 hindurchtritt. An dem in den Federraum 46 ragenden Ende des Schaftteils 52 stützt sich der Federteller 51 ab. Die Verbindungsbohrung 53 weist einen kleineren Durchmesser auf als der Federraum 46 und der Speicherraum 55. Der Ausweichkolben 50 weist im Speicherraum 55 einen Bereich 56 mit größerem Durchmesser auf als die Verbindungsbohrung 53, so daß eine Hubbewegung des Ausweichkolbens 50 in den Federraum 46 hinein dadurch begrenzt ist, daß der Bereich 56 des Ausweichkolbens 50 an der Trennwand 54 als Anschlag zur Anlage kommt. Der Ausweichkolben 50 ist mit seinem Bereich 56 in der Bohrung 80 mit gegenüber der Verbindungsbohrung 53 entsprechend größerem Durchmesser dicht geführt. Der Federraum 46 ist als Bohrung in einem Gehäuseteil 82 ausgebildet, das einen Teil des Ventilkörpers 26 bildet. Der Kanal 48 verläuft durch das Gehäuseteil 82 versetzt zum Federraum 46 etwa parallel zu diesem.The closing spring 44 is supported, on the one hand, at least indirectly, for example via a spring plate, on the injection valve member 28 and, on the other hand, at least indirectly, for example also via a spring plate 51, on a bypass piston 50. The bypass piston 50 is guided in a bore 80 of a housing part 81 and has at its end of the closing spring 44 facing a shaft portion 52 which through a connecting hole 53 in a partition wall 54 of the housing part 81 passes between the spring chamber 46 and a subsequent thereto in the housing part 81 storage space 55. At the projecting into the spring chamber 46 end of the shaft portion 52, the spring plate 51 is supported. The connecting bore 53 has a smaller diameter than the spring chamber 46 and the storage space 55. The bypass piston 50 has in the storage chamber 55 a region 56 with a larger diameter than the connecting bore 53, so that a stroke movement of the bypass piston 50 in the spring chamber 46 thereby limited is that the area 56 of the bypass piston 50 comes to the partition wall 54 as a stop to the plant. The bypass piston 50 is guided with its portion 56 in the bore 80 with respect to the connecting hole 53 correspondingly larger diameter. The spring chamber 46 is formed as a bore in a housing part 82, which forms part of the valve body 26. The channel 48 extends through the housing part 82 offset from the spring chamber 46 approximately parallel to this.

Vom Speicherraum 55 führt von dessen dem Federraum 46 abgewandtem Ende eine Bohrung 58 zum Pumpenarbeitsraum 22 hin im Gehäuseteil 81 ab. Die Bohrung 58 weist einen kleineren Durchmesser auf als die Bohrung 80. Der Ausweichkolben 50 weist zur Bohrung 58 hin an den Bereich 56 anschließend eine Dichtfläche 60 auf, die beispielsweise etwa kegelförmig ausgebildet ist. Die Dichtfläche 60 wirkt mit der Mündung der Bohrung 58 in den Speicherraum 55 am Gehäuseteil 81 als Sitz zusammen, die ebenfalls etwa kegelförmig ausgebildet sein kann. Der Ausweichkolben 50 weist einen in die Bohrung 58 ragenden Schaft 62 auf, dessen Durchmesser kleiner als der des Bereichs 56 ist. Der Schaft 62 weist an die Dichtfläche 60 anschließend zunächst einen wesentlich kleineren Durchmesser auf als die Bohrung 58 und zu seinem freien Ende hin anschließend einen Schaftbereich 64 mit einem Durchmesser, der nur wenig kleiner ist als der Durchmesser der Bohrung 58. Der Schaftbereich 64 kann an seinem Umfang eine oder mehrere Abflachungen 65 aufweisen, durch die Öffnungen zwischen dem Schaftbereich 64 und der Bohrung 58 gebildet werden, durch die Kraftstoff in den Speicherraum 55 gelangen kann.From the storage space 55 leads away from the spring chamber 46 facing away from the end of a bore 58 to the pump working chamber 22 in the housing part 81 from. The bore 58 has a smaller diameter than the bore 80. The bypass piston 50 has the bore 58 toward the region 56 then a sealing surface 60, which is formed for example approximately conical. The sealing surface 60 cooperates with the mouth of the bore 58 in the storage space 55 on the housing part 81 as a seat, which may also be formed approximately conical. The bypass piston 50 has a shaft 62 protruding into the bore 58, the diameter of which is smaller than that of the region 56. The shaft 62 then initially has a substantially smaller diameter on the sealing surface 60 than the bore 58 and, toward its free end, subsequently a shaft region 64 with a diameter which is only slightly smaller than that Diameter of the bore 58. The shaft portion 64 may have at its periphery one or more flats 65 through which openings are formed between the shaft portion 64 and the bore 58 through which fuel may enter the storage space 55.

Zwischen dem Gehäuseteil 81 und dem Pumpenkörper 14 ist eine Zwischenscheibe 83 angeordnet, in der eine Bohrung 84 ausgebildet ist, durch die die Bohrung 58 im Gehäuseteil 81 mit dem Pumpenarbeitsraum 22 verbunden ist. Die Bohrung 84 stellt eine erste Drosselstelle dar, über die die Bohrung 58 mit dem Pumpenarbeitsraum 22 verbunden ist. Der Ausweichkolben 50 begrenzt in der Bohrung 58 zur Zwischenscheibe 83 hin einen Vorraum 85, der über die erste Drosselstelle 84 mit dem Pumpenarbeitsraum 22 verbunden ist.Between the housing part 81 and the pump body 14, an intermediate disc 83 is arranged, in which a bore 84 is formed, through which the bore 58 is connected in the housing part 81 with the pump working chamber 22. The bore 84 represents a first throttle point, via which the bore 58 is connected to the pump working chamber 22. The bypass piston 50 delimits in the bore 58 to the intermediate disc 83 toward an antechamber 85, which is connected via the first throttle point 84 to the pump working chamber 22.

Wenn sich der Ausweichkolben 50 in einer Ausgangsstellung befindet, in der dieser mit seiner Dichtfläche 60 am Dichtsitz an der Mündung der Bohrung 58 anliegt, so ist der Speicherraum 55 vom Vorraum 85 und damit vom Pumpenarbeitsraum 22 getrennt. In der Ausgangsstellung des Ausweichkolbens 50 wirkt der im Pumpenarbeitsraum 22 herrschende Druck auf die Stirnfläche des Schaftbereichs 64 und durch die Öffnungen zwischen dem Schaftbereich 64 und der Bohrung 58 auf die Dichtfläche 60 des Speicherkolbens 50 entsprechend dem Durchmesser der Bohrung 58. Der Ausweichkolben 50 wird durch die Kraft der Schließfeder 44 gegen den im Pumpenarbeitsraum 22 und damit im Vorraum 85 herrschenden Druck in seiner Ausgangsstellung gehalten, wenn die durch den Druck im Pumpenarbeitsraum 22 auf den Speicherkolben 50 ausgeübte Kraft geringer ist als die Kraft der Schließfeder 44.When the deflecting piston 50 is in an initial position in which it rests with its sealing surface 60 on the sealing seat at the mouth of the bore 58, the storage space 55 is separated from the antechamber 85 and thus from the pump working chamber 22. In the initial position of the bypass piston 50, the pressure prevailing in the pump working space 22 acts on the end face of the shaft portion 64 and through the openings between the shaft portion 64 and the bore 58 on the sealing surface 60 of the accumulator piston 50 corresponding to the diameter of the bore 58. The bypass piston 50 is through held the force of the closing spring 44 against the pressure prevailing in the pump chamber 22 and thus in the antechamber 85 pressure in its initial position when the force exerted by the pressure in the pump chamber 22 on the accumulator piston 50 force is less than the force of the closing spring 44th

Wenn der Druck im Pumpenarbeitsraum 22 und damit im Vorraum 85 so stark ansteigt, daß die auf den Ausweichkolben 50 erzougte Kraft größer ist als die Kraft der Schließfeder 44, so bewegt sich der Ausweichkolben 50 und mit diesem der Schaftteil 52 in einer Ausweichbewegung in den Speicherraum 55, wobei sich der Schaftteil 52 in den Federraum 46 bewegt. Bei der Ausweichbewegung des Ausweichkolbens 50 wird Kraftstoff aus dem Speicherraum 55 in den Federraum 46 verdrängt, der durch einen Ringspalt zwischen dem Schaftteil 52 des Ausweichkolbens 50 und der Verbindungsbohrung 53 hindurchtreten muß. Hierdurch wird eine Dämpfung der Ausweichbewegung des Schaftteils 52 und damit des Ausweichkolbens 50 erreicht.When the pressure in the pump working space 22 and thus in the antechamber 85 increases so much that the force developed on the escape piston 50 is greater than the force of the closing spring 44, Thus, the bypass piston 50 and with this the shaft part 52 moves in an evasive movement into the storage space 55, wherein the shaft part 52 moves into the spring chamber 46. In the evasive movement of the bypass piston 50, fuel is displaced from the storage chamber 55 into the spring chamber 46, which has to pass through an annular gap between the shaft part 52 of the bypass piston 50 and the connecting bore 53. As a result, an attenuation of the deflection movement of the shaft part 52 and thus of the bypass piston 50 is achieved.

Zum Kraftstoffeinspritzventil 12 hin anschließend ist an das Gehäuseteil 82 ein weiteres Gehäuseteil 86 als Teil des Ventilkörpers 26 angeordnet, das eine Bohrung 87 aufweist, durch die ein Endbereich des Einspritzventilglieds 28 hindurchtritt und in den Federraum 46 ragt. Das Einspritzventilglied 28 stützt sich mit seinem Endbereich im Federraum 46 über einen Federteller 88 an der Schließfeder 44 ab. Der Endbereich des Einspritzventilglieds 28 weist einen kleineren Durchmesser auf als dessen in der Bohrung 30 geführter Bereich. Die Bohrung 30, der Druckraum 40 sowie der Ringraum 38, an dessen unterem Ende der Ventilsitz 34 und die Einspritzöffnungen 32 angeordnet sind, sind in einem einen Teil des Ventilkörpers 26 bildenden Ventilgehäuse 89 ausgebildet. Zwischen dem Gehäuseteil 86 und dem Ventilgehäuse 89 ist eine Zwischenscheibe 90 mit geringer Dicke angeordnet. Die Zwischenscheibe 90 weist eine Bohrung 91 auf, durch die der Endbereich des Einspritzventilglieds 28 hindurchtritt.Subsequently to the fuel injection valve 12, a further housing part 86 is arranged on the housing part 82 as part of the valve body 26, which has a bore 87 through which an end region of the injection valve member 28 passes and protrudes into the spring chamber 46. The injection valve member 28 is supported with its end region in the spring chamber 46 via a spring plate 88 on the closing spring 44. The end portion of the injection valve member 28 has a smaller diameter than the guided in the bore 30 area. The bore 30, the pressure chamber 40 and the annular space 38, at the lower end of the valve seat 34 and the injection ports 32 are arranged in a part of the valve body 26 forming valve housing 89 are formed. Between the housing part 86 and the valve housing 89, an intermediate disc 90 is arranged with a small thickness. The washer 90 has a bore 91 through which the end portion of the injection valve member 28 passes.

Der Kanal 48 verläuft vom Druckraum 40 aus durch das Ventilgehäuse 89, die Zwischenscheibe 90, das Gehäuseteil 86, das Gehäuseteil 82 und die Zwischenscheibe 83. Die Zwischenscheibe 83 weist auf ihrer dem Pumpenkörper 14 zugewandten Seite eine Nut 92 auf, die zum Pumpenarbeitsraum 22 hin offen ist und in die der Kanal 48 mündet. Die Nut 92 kann beispielsweise etwa radial zu der Zylinderbohrung 16 verlaufen und erstreckt sich von der Zylinderbohrung 16 nach außen bis in den Bereich der Zwischenscheibe 83, in dem der Kanal 48 durch diese verläuft. Die Verbindung des Druckraums 40 des Kraftstoffeinspritzventils 12 mit dem Pumpenarbeitsraum 22 durch den Kanal 48 erfolgt somit direkt unter Umgehung des Vorraums 85, der vom Ausweichkolben 50 in der Bohrung 58 zur Zwischenscheibe 83 hin begrenzt wird. In dem den Druckraum 48 mit dem Pumpenarbeitsraum 22 verbindenden Kanal 48 ist wenigstens eine zweite Drosselstelle 93 vorgesehen. Durch die zweite Drosselstelle 93 kann eine Dämpfung von Druckschwingungen im Kanal 48 erreicht werden. Die zweite Drosselstelle 93 kann durch eine gezielte Verringerung des Querschnitts des Kanals 48 gebildet werden. Es kann hierbei insbesondere vorgesehen sein, daß der Kanal 40 in der Zwischenscheibe 83 und/oder in der Zwischenscheibe 90 zur Bildung der Drosselstelle 93 als Drosselbohrung mit definiertem Querschnitt ausgebildet ist. Die erste Drosselstelle 84 und die zweite Drosselstelle 93 können unabhängig voneinander für die jeweilige Funktion optimal gewählt werden.The channel 48 extends from the pressure chamber 40 through the valve housing 89, the washer 90, the housing part 86, the housing part 82 and the washer 83. The washer 83 has on its side facing the pump body 14 a groove 92, the pump working space 22 out is open and into which the channel 48 opens. The groove 92 For example, it may extend approximately radially to the cylinder bore 16 and extends outwardly from the cylinder bore 16 to the region of the washer 83 in which the channel 48 passes therethrough. The connection of the pressure chamber 40 of the fuel injection valve 12 with the pump working chamber 22 through the channel 48 thus takes place directly bypassing the vestibule 85, which is limited by the bypass piston 50 in the bore 58 to the washer 83 out. In the pressure chamber 48 with the pump working chamber 22 connecting channel 48 at least a second throttle body 93 is provided. By the second throttle body 93, a damping of pressure oscillations in the channel 48 can be achieved. The second throttle body 93 can be formed by a targeted reduction of the cross section of the channel 48. It may be provided in particular that the channel 40 in the intermediate disc 83 and / or in the intermediate disc 90 is formed to form the throttle body 93 as a throttle bore with a defined cross-section. The first throttle body 84 and the second throttle body 93 can be selected independently of each other for the respective function optimally.

Das Kraftstoffeinspritzventil 12 und die Kraftstoffhochdruckpumpe 10 sind mittels einer Spannhülse 94 miteinander verbunden. Die Spannhülse 94 übergreift das Ventilgehäuse 89 und ist in eine Gewindebohrung 95 im Pumpenkörper 14 eingeschraubt. Die Zwischenscheibe 83, die Gehäuseteile 81,82,86 sowie die Zwischenscheibe 90 sind zwischen dem Ventilgehäuse 89 und dem Pumpenkörper 14 eingespannt.The fuel injection valve 12 and the high-pressure fuel pump 10 are connected to each other by means of a clamping sleeve 94. The clamping sleeve 94 engages over the valve housing 89 and is screwed into a threaded bore 95 in the pump body 14. The intermediate disc 83, the housing parts 81, 82, 86 and the intermediate disc 90 are clamped between the valve housing 89 and the pump body 14.

Nachfolgend wird die Funktion der Kraftstoffeinspritzeinrichtung erläutert. Der Pumpenarbeitsraum 22 wird während des Saughubs des Pumpenkolbens 18 mit Kraftstoff gefüllt. Beim Förderhub des Pumpenkolbens 18 ist das Steuerventil 23 zunächst geöffnet, so daß sich im Pumpenarbeitsraum 22 kein Hochdruck aufbauen kann. Wenn die Kraftstoffeinspritzung beginnen soll, so wird das Steuerventil 23 durch die Steuereinrichtung 25 geschlossen, so daß der Pumpenarbeitsraum 22 vom Kraftstoffvorratsbehälter 24 getrennt ist und sich in diesem Hochdruck aufbaut. Wenn der Druck im Pumpenarbeitsraum 22 und im Druckraum 40 so hoch ist, daß die über die Druckschulter 42 auf das Einspritzventilglied 28 wirkende Kraft in Öffnungsrichtung 29 größer ist als die Kraft der Schließfeder 44, so bewegt sich das Einspritzventilglied 28 in Öffnungsrichtung 29 und gibt die wenigstens eine Einspritzöffnung 32 frei, durch die Kraftstoff in den Brennraum des Zylinders eingespritzt wird. Der Ausweichkolben 50 befindet sich hierbei in seiner Ausgangsstellung. Der Druck im Pumpenarbeitsraum 22 steigt nachfolgend entsprechend dem Profil des den Pumpenkolben 18 antreibenden Nockens weiter an.The function of the fuel injector will be explained below. The pump working space 22 is filled with fuel during the suction stroke of the pump piston 18. During the delivery stroke of the pump piston 18, the control valve 23 is initially opened, so that no high pressure can build up in the pump working chamber 22. When the fuel injection is to begin, the control valve 23 is closed by the control means 25, so that the pump working space 22 is separated from the fuel tank 24 and builds up in this high pressure. If the pressure in the pump chamber 22 and in the pressure chamber 40 is so high that the force acting on the injection valve member 28 on the injection valve member 28 force in the opening direction 29 is greater than the force of the closing spring 44, the injection valve member 28 moves in the opening direction 29 and outputs the at least one injection port 32 free, is injected through the fuel into the combustion chamber of the cylinder. The bypass piston 50 is in this case in its starting position. The pressure in the pump working chamber 22 subsequently increases in accordance with the profile of the pump piston 18 driving cam further.

Wenn die durch den im Pumpenarbeitsraum 22 und damit im Vorraum 85 herrschenden Druck auf den Ausweichkolben 50 ausgeübte Kraft größer wird als die durch die Schließfeder 44 auf den Ausweichkolben 50 ausgeübte Kraft, so führt der Ausweichkolben 50 seine Ausweichhubbewegung aus und bewegt sich in den Speicherraum 55. Hierbei wird ein Druckabfall im Pumpenarbeitsraum 22 verursacht und außerdem die Vorspannung der Schließfeder 44 erhöht, die sich über den Schaftteil 52 am Speicherkolben 50 abstützt. Durch den Druckabfall im Pumpenarbeitsraum 22 und im Druckraum 40 ergibt sich eine geringere Kraft in Öffnungsrichtung 29 auf das Einspritzventilglied 28 und infolge der Erhöhung der Vorspannung der Schließfeder 44 ergibt sich eine erhöhte Kraft in Schließrichtung auf das Einspritzventilglied 28, so daß dieses wieder in Schließrichtung bewegt wird, mit seiner Dichtfläche 34 am Ventilsitz 36 zur Anlage kommt und die Einspritzöffnungen 32 verschließt, so daß die Kraftstoffeinspritzung unterbrochen wird. Das Kraftstoffeinspritzventil 12 ist dabei nur für eine kurze Zeitdauer geöffnet und es wird nur eine geringe Menge Kraftstoff als Voreinspritzung in den Brennraum eingespritzt. Die eingespritzte Kraftstoffmenge ist im wesentlichen vom Öffnungsdruck des Ausweichkolbens 50 bestimmt, das ist der Druck im Pumpenarbeitsraum 22 und im Vorraum 85, bei dem der Ausweichkolben 50 seine Ausweichhubbewegung beginnt. Der Öffnungshub des Einspritzventilglieds 28 während der Voreinspritzung kann durch eine Dämpfungseinrichtung hydraulisch begrenzt sein. Eine solche Dämpfungseinheit ist durch die DE 39 00 762 A1 sowie die korrespondierende US-5, 125, 580 sowie die DE 39 00 763 A1 sowie die korrespondierende US-5,125,581 bekannt. Die Hubbewegung des Ausweichkolbens 50 kann ebenfalls mittels einer Dämpfungseinrichtung gedämpft werden, wie diese in der DE 39 00 762 A1, der DE 39 00 763 A1, der US-5,125,580 und der US-5,125,581 beschrieben ist.If the force exerted on the bypass piston 50 by the pressure prevailing in the pump working chamber 22 and thus in the antechamber 85 becomes greater than the force exerted by the closing spring 44 on the bypass piston 50, the bypass piston 50 executes its evasive stroke movement and moves into the reservoir 55 In this case, a pressure drop in the pump working chamber 22 is caused and also increases the bias of the closing spring 44, which is supported on the shaft portion 52 on the accumulator piston 50. Due to the pressure drop in the pump chamber 22 and in the pressure chamber 40 results in a lower force in the opening direction 29 on the injection valve member 28 and due to the increase in the bias of the closing spring 44 results in an increased force in the closing direction of the injection valve member 28 so that it moves back in the closing direction is, with its sealing surface 34 comes to rest on the valve seat 36 and the injection ports 32 closes, so that the fuel injection is interrupted. The Fuel injection valve 12 is open only for a short period of time and it is injected only a small amount of fuel as a pilot injection into the combustion chamber. The injected amount of fuel is essentially determined by the opening pressure of the bypass piston 50, that is the pressure in the pump working chamber 22 and in the anteroom 85, in which the bypass piston 50 begins its evasive stroke movement. The opening stroke of the injection valve member 28 during the pilot injection may be hydraulically limited by a damper. Such a damping unit is known from DE 39 00 762 A1 and the corresponding US-5, 125, 580 and DE 39 00 763 A1 and the corresponding US-5,125,581. The lifting movement of the bypass piston 50 can also be damped by means of a damping device, as described in DE 39 00 762 A1, DE 39 00 763 A1, US 5,125,580 and US 5,125,581.

Der Druck im Pumpenarbeitsraum 22 steigt nachfolgend weiter an entsprechend dem Profil des den Pumpenkolben 18 antreibenden Nockens, so daß die auf das Einspritzventilglied 28 wirkende Druckkraft in Öffnungsrichtung 29 wieder zunimmt und die infolge der erhöhten Vorspannung der Schließfeder 44 erhöhte Schließkraft übersteigt, so daß das Kraftstoffeinspritzventil 12 wieder öffnet. Dabei wird eine größere Kraftstoffmenge über eine längere Zeitdauer eingespritzt als während der Voreinspritzung. Die Zeitdauer und die während dieser Haupteinspritzung eingespritzte Kraftstoffmenge werden durch den Zeitpunkt bestimmt, zu dem das Steuerventil 23 durch die Steuereinrichtung 25 wieder geöffnet wird. Nach dem Öffnen des Steuerventils 23 ist der Pumpenarbeitsraum 22 wieder mit dem Kraftstoffvorratsbehälter 24 verbunden, so daß dieser entlastet ist und das Kraftstoffeinspritzventil 12 schließt. Der Ausweichkolben 50 mit dem Schaftteil 52 wird durch die Kraft der Schließfeder 44 wieder in seine Ausgangsstellung zurückbewegt. Der zeitliche Versatz zwischen der Voreinspritzung und der Haupteinspritzung ist hauptsächlich durch den Ausweichhub des Ausweichkolbens 50 bestimmt.The pressure in the pump chamber 22 continues to increase according to the profile of the pump piston 18 driving cam, so that the force acting on the injection valve member 28 compressive force in the opening direction 29 increases again and 44 exceeds the increased closing force due to the increased bias of the closing spring, so that the fuel injection valve 12 opens again. In this case, a larger amount of fuel is injected over a longer period of time than during the pilot injection. The time duration and the amount of fuel injected during this main injection are determined by the time at which the control valve 23 is opened again by the control device 25. After opening the control valve 23, the pump working chamber 22 is again connected to the fuel tank 24, so that this is relieved and the fuel injection valve 12 closes. The bypass piston 50 with the shaft part 52 is moved back into its initial position by the force of the closing spring 44. The time offset between the pilot injection and the main injection is determined mainly by the deflection stroke of the bypass piston 50.

Claims (4)

  1. Fuel injection device for an internal combustion engine having a high-pressure fuel pump (10) and a fuel injection valve (12) for a cylinder of the internal combustion engine, with the high-pressure fuel pump (10) having a pump piston (18) which is driven in a reciprocating movement via the internal combustion engine and bounds a pump working space (22), having an electrically controlled valve (23) by which a connection of the pump working space (22) to a relief space (24) is controlled, with the fuel injection valve (12) having an injection valve element (28) by which at least one injection opening (32) is controlled and which can be moved in an opening direction (29) counter to the force of a closing spring (44) arranged in a spring space (46), by the pressure prevailing in a pressure space (40) which is connected to the pump working space (22), with the closing spring (44) being supported on the one hand at least indirectly on the injection valve element (28) and on the other hand at least indirectly on a displaceable bypass piston (50) which bounds, on its side facing away from the closing spring (44), a prespace (85) which is connected to the pump working space (22), with the bypass piston (50) being capable of being moved into a storage space (55) from an initial position counter to the force of the closing spring (44) when there is a low pressure in the pump working space (22), with the prespace (85) being connected to the pump working space (22) exclusively via a first throttle point (84), and with the pressure space (40) of the fuel injection valve (12) being connected directly to the pump working space (22) while bypassing the prespace (85), characterized in that the pressure space (40) of the fuel injection valve (12) is connected to the pump working space (22) via at least one second throttle point (93).
  2. Fuel injection device according to Claim 1, characterized in that the first throttle point (84) between the prespace (85) and the pump working space (22) is embodied as a throttle bore in an intermediate plate (83) between a pump body (14), in which the pump piston (18) is guided, and a housing part (81), in which the bypass piston (50) is guided.
  3. Fuel injection device according to Claim 1 or 2, characterized in that the at least one second throttle point (93) is arranged in a housing part (86; 89) of the fuel injection valve (12).
  4. Fuel injection device according to Claim 1 or 2, characterized in that the at least one second throttle point (93) is arranged in an intermediate plate (90) between housing parts (86, 89) of the fuel injection valve (12).
EP02742765A 2001-06-19 2002-05-18 Fuel injection device for an internal combustion engine Expired - Lifetime EP1402174B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE20110130U DE20110130U1 (en) 2001-06-19 2001-06-19 Fuel injection device for an internal combustion engine
DE20110130U 2001-06-19
PCT/DE2002/001799 WO2002103197A1 (en) 2001-06-19 2002-05-18 Fuel injection device for an internal combustion engine

Publications (2)

Publication Number Publication Date
EP1402174A1 EP1402174A1 (en) 2004-03-31
EP1402174B1 true EP1402174B1 (en) 2006-04-12

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ID=7958262

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Application Number Title Priority Date Filing Date
EP02742765A Expired - Lifetime EP1402174B1 (en) 2001-06-19 2002-05-18 Fuel injection device for an internal combustion engine

Country Status (7)

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US (1) US6845757B2 (en)
EP (1) EP1402174B1 (en)
JP (1) JP2004521248A (en)
DE (2) DE20110130U1 (en)
HU (1) HUP0303548A2 (en)
PL (1) PL370296A1 (en)
WO (1) WO2002103197A1 (en)

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Publication number Priority date Publication date Assignee Title
DE10119603A1 (en) * 2001-04-21 2002-10-24 Bosch Gmbh Robert Fuel injection arrangement has fuel pump with piston defining a pump operating chamber, balancing chamber, valve, piston with shaft part, connecting hole and gap
DE10119602A1 (en) * 2001-04-21 2002-10-24 Bosch Gmbh Robert Fuel injection unit consists of fuel pump with piston and chamber, control valve, closure spring, stop, shaft part, connecting hole and smaller and larger diameter shaft parts
DE10338081A1 (en) * 2003-08-19 2005-03-10 Bosch Gmbh Robert Fuel injector
JP3994990B2 (en) * 2004-07-21 2007-10-24 株式会社豊田中央研究所 Fuel injection device
US7287493B2 (en) * 2004-11-10 2007-10-30 Buck Supply Co., Inc. Internal combustion engine with hybrid cooling system
US7287494B2 (en) * 2004-11-10 2007-10-30 Buck Supply Co., Inc. Multicylinder internal combustion engine with individual cylinder assemblies and modular cylinder carrier
DE102004057151B4 (en) * 2004-11-26 2009-04-16 Continental Automotive Gmbh Injection valve with a pressure-holding valve for fluid pressure of a spring chamber
DE102005055359A1 (en) * 2005-11-21 2007-05-24 Robert Bosch Gmbh Intermediate plate for a fuel injector and fuel injector
US8316814B2 (en) * 2009-06-29 2012-11-27 Buck Kenneth M Toploading internal combustion engine

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AT378242B (en) * 1981-07-31 1985-07-10 Berchtold Max Prof FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES, ESPECIALLY DIESEL ENGINES
US4572433A (en) * 1984-08-20 1986-02-25 General Motors Corporation Electromagnetic unit fuel injector
DE3900763C2 (en) 1989-01-12 1994-05-19 Robert Bosch Ag Wien Fuel injection nozzle, in particular pump nozzle, for an internal combustion engine
EP0404917A1 (en) * 1989-01-12 1991-01-02 VOEST-ALPINE AUTOMOTIVE Gesellschaft m.b.H. Fuel injection nozzle
US5012786A (en) * 1990-03-08 1991-05-07 Voss James R Diesel engine fuel injection system
US5328094A (en) * 1993-02-11 1994-07-12 General Motors Corporation Fuel injector and check valve
GB9520243D0 (en) 1995-10-04 1995-12-06 Lucas Ind Plc Injector
DE19752834A1 (en) * 1997-11-28 1999-06-02 Bosch Gmbh Robert Fuel injection device for internal combustion engines
DE19844891A1 (en) * 1998-09-30 2000-04-06 Bosch Gmbh Robert Fuel injection valve for internal combustion engines

Also Published As

Publication number Publication date
DE50206396D1 (en) 2006-05-24
US20040099250A1 (en) 2004-05-27
HUP0303548A2 (en) 2004-03-01
WO2002103197A1 (en) 2002-12-27
US6845757B2 (en) 2005-01-25
JP2004521248A (en) 2004-07-15
DE20110130U1 (en) 2002-10-24
PL370296A1 (en) 2005-05-16
EP1402174A1 (en) 2004-03-31

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