EP1125049B1 - Combined stroke/pressure controlled fuel injection method and system for an internal combustion engine - Google Patents

Combined stroke/pressure controlled fuel injection method and system for an internal combustion engine Download PDF

Info

Publication number
EP1125049B1
EP1125049B1 EP00958207A EP00958207A EP1125049B1 EP 1125049 B1 EP1125049 B1 EP 1125049B1 EP 00958207 A EP00958207 A EP 00958207A EP 00958207 A EP00958207 A EP 00958207A EP 1125049 B1 EP1125049 B1 EP 1125049B1
Authority
EP
European Patent Office
Prior art keywords
pressure
fuel
injection
space
control
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
EP00958207A
Other languages
German (de)
French (fr)
Other versions
EP1125049A1 (en
Inventor
Bernd Mahr
Martin Kropp
Hans-Christoph Magel
Wolfgang Otterbach
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1125049A1 publication Critical patent/EP1125049A1/en
Application granted granted Critical
Publication of EP1125049B1 publication Critical patent/EP1125049B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • 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
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/02—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor being spaced from pumping elements
    • F02M41/06—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor being spaced from pumping elements the distributor rotating
    • 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
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/16—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor characterised by the distributor being fed from a constant pressure source, e.g. accumulator or constant pressure positive displacement pumps
    • 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
    • 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
    • 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
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
    • F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
    • F02M59/105—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive hydraulic drive
    • 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
    • F02M63/0003—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure
    • F02M63/0007—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure using electrically actuated 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
    • 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
    • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • 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 invention is based on a fuel injection method for an internal combustion engine of the genus Claim 1 and a fuel injection system according to the preamble of claim 4.
  • Such a fuel injection method and system has become known, for example, from WO 98/09068.
  • a pressure-controlled fuel injection system the fuel pressure prevailing in the nozzle space of an injector opens a valve body (for example a nozzle needle) against the action of a closing force and thus releases the injection opening for an injection of the fuel.
  • the pressure at which fuel exits the nozzle chamber into the cylinder is called the injection pressure.
  • a stroke-controlled fuel injection system is understood in the context of the invention that the opening and closing of the injection opening of an injector take place with the aid of a displaceable valve member due to the hydraulic interaction of the fuel pressures in a nozzle chamber and in a control chamber.
  • an arrangement is referred to below as central if it is intended for all cylinders together and as local if it is intended for only a single cylinder.
  • EP 0 711 914 A1 describes a pressure-controlled fuel injection system known, in which a valve control unit either the lower or higher fuel pressure is directed into the injector nozzle area. There becomes a spring-loaded valve body by the pressure lifted its valve seat so that fuel from the Injection port can leak.
  • pressure-controlled injection systems are pressure waves during injection kindled the main injection with the higher one Fuel pressure is wanted, but during pre-injection with the lower fuel pressure a negative influence on the hydraulic behavior of the injection system the subsequent main injection.
  • the lower fuel pressure can also be used for the main injection to realize a boat-shaped injection process be used.
  • first embodiment of a lifting / pressure-controlled fuel injection system 1 promotes a quantity-controlled high-pressure pump 2 fuel 3 from a storage tank 4 under high pressure via a delivery line 5 in a central pressure accumulator 6 (high-pressure common rail), from which a plurality Drain the high-pressure lines 7 corresponding to the number of individual cylinders to the individual injectors 8 (injection device) projecting into the combustion chamber of the internal combustion engine to be supplied.
  • a first higher fuel pressure of approximately 300 bar to 1800 bar can be stored in the pressure accumulator 6.
  • the higher fuel pressure in the high-pressure line 7 is conducted by energizing a 3/2-way valve 9 via a pressure line 10 into a nozzle chamber 11 of the injector 8.
  • the injection with the higher fuel pressure (main injection) is pressure-controlled with the aid of a piston-shaped valve member 12 (nozzle needle) which is axially displaceable in a guide bore and whose conical valve sealing surface 13 interacts with a valve seat surface on the injector housing and thus closes the injection openings 14 provided there.
  • a pressure surface of the valve element 12 pointing in the opening direction of the valve element 12 is exposed to the pressure prevailing there, the nozzle space 11 continuing through an annular gap between the valve element 12 and the guide bore up to the valve sealing surface 13 of the injector 8.
  • the valve member 12 sealing the injection openings 14 is opened against the action of a closing force (closing spring 15), the spring chamber 16 being relieved of pressure by means of a leakage line 17 .
  • a closing force closing spring 15
  • the spring chamber 16 being relieved of pressure by means of a leakage line 17 .
  • the leakage line 20 serves to relieve pressure and can lead back into the storage tank 4.
  • the higher fuel pressure initially prevailing in the pressure line 10 and the nozzle chamber 11 is reduced to the lower fuel pressure which is stored in an accumulator chamber 21 connected to the connecting line 18.
  • This lower fuel pressure is used for pre and / or post injection (HC enrichment for exhaust gas aftertreatment).
  • the control chamber 24 has a fuel inlet 25 with a first throttle 26 and a fuel outlet from the connecting line 18 to a pressure relief line 27 with a second throttle 28 , which can be connected to the leakage line 20 by a control element in the form of a 2/2-way valve 29 is.
  • the pressure piece 22 is pressurized in the closing direction by the pressure in the control chamber 24.
  • the pressure in the control chamber 24 can be reduced, so that as a result the pressure acting on the valve member 12 in the opening direction exceeds the pressure acting on the valve member 12 in the closing direction ,
  • the valve sealing surface 13 lifts off from the valve seat surface, so that an injection takes place with the lower fuel pressure.
  • the relief process of the control chamber 24 and thus the stroke control of the valve member 12 can be influenced by the dimensioning of the two throttles 26, 28.
  • This injection is then ended by closing the 2/2-way valve 29.
  • the injection with the lower system pressure can take place either after the main injection as a post-injection or before the main injection as a pre-injection.
  • the accumulator chamber 21 is still sufficiently filled with pressurized fuel even after a post-injection, this fuel can be used for a pre-injection during the next injection cycle, whereby a pre-injection and post-injection is possible for each injection cycle.
  • the size of the accumulator chamber 21 is adapted to the requirements of the pre-injection and post-injection, the function of the accumulator chamber 21 also being able to fulfill a sufficiently long pressure line.
  • 3/2-way valve 9, pressure relief valve 19 and accumulator space 21, designated overall by 30 in FIG. 1, can be arranged either inside the injector housing ( FIG. 1a ) or outside ( FIG. 1b ).
  • the central pressure accumulator of FIG. 1 is omitted, and the pressure is built up by energizing a 2/2-way valve 41.
  • the high-pressure pump 2 can have a fuel pressure of approximately 300 to approximately 1600 bar generate and be a cam pump, for example.
  • a central distributor device 42 distributes this fuel pressure to the individual injectors 43 . Behind the distributor device 42 there is a non-return valve 44 for each injector 43, which allows the fuel to flow in the direction of the injector 43, and a pressure relief valve 45 that opens at approx. 300 bar, which allows fuel to flow back from the injector 43 to relieve the distributor device 42 and Allows pressure reduction, provided.
  • Check valve 44 and pressure relief valve 45 form the overall valve arrangement designated 46 .
  • control chamber 24 of the injector 43 now also has its fuel inlet 25 from the pressure line 10 and the accumulator chamber 47 is arranged in the pressure line 10 directly in front of the nozzle chamber 11.
  • the pressure in the control chamber 24 is limited to approximately 300 bar via a pressure limiting valve 48 .
  • This pressure limiting valve 48 can also be integrated in the 2/2-way valve 29 or in a corresponding solenoid valve.
  • the valve arrangement 46 provides the one present in the injector 43 Fuel when the 2/2-way valve 41 is not energized under the lower fuel pressure.
  • By opening (energizing) of the 2/2-way valve 29 is pre-injected in a stroke-controlled manner from the local accumulator 47.
  • the higher system pressure activated, the pressure in the nozzle chamber 11 and in increases Control chamber 24 so that the pressure relief valve 48th opens and the pressure there is limited to a low level is.
  • the valve member 12 open pressure controlled.
  • the pressure in the injector drops 43 via the pressure relief valve 45 to the lower one Fuel pressure down, so that the stroke control is active again is and the valve member 12 closes.
  • the pressure-limiting valve arrangement 46a is formed by a 3/2-way valve 49 and a pressure-limiting valve 45a that opens at approximately 300 bar.
  • the pressure line 10 is connected to the distributor device 42 via the 3/2-way valve 49.
  • the pressure prevailing in the injector 43 is reduced to the lower fuel pressure for a pre-injection and / or post-injection via the pressure relief valve 45a.
  • valve arrangement 46a is provided in FIG. 3a and the valve arrangement 46 in FIG. 3b .
  • the injection system 60 shown in FIG. 4 corresponds to the injection system 1 with the exception of the generation of the higher fuel pressure.
  • the high-pressure pump 2 delivers fuel into a first central pressure accumulator 61 (low-pressure common rail).
  • the fuel stored there under a pressure of approx. 200 to 600 bar is compressed to the higher fuel pressure (approx. 600 to approx. 1800 bar) by means of a central pressure translation unit 62 and stored in the second central pressure accumulator 6.
  • the pressure booster unit 62 comprises a valve unit 63 for pressure booster control, a pressure booster 64 with a pressure medium 65 in the form of a displaceable piston element, and two check valves 66 and 67 .
  • the pressure medium 65 can be connected at one end with the aid of the valve unit 63 to the first pressure accumulator 61, so that it is pressurized at one end by the fuel in a primary chamber 68 .
  • a differential space 69 is relieved of pressure by means of a leakage line 70 , so that the pressure medium 65 can be displaced in the compression direction in order to reduce the volume of a pressure chamber 71.
  • the fuel located in the pressure chamber 71 is compressed to the higher fuel pressure in accordance with the area ratio of the primary chamber 68 and the pressure chamber 71 and supplied to the second pressure accumulator 6.
  • the check valve 66 prevents the backflow of compressed fuel from the second pressure accumulator 6.
  • the pressure medium 65 is reset and the pressure chamber 71 is refilled, via the check valve 67 the first pressure accumulator 61 is connected. Due to the pressure conditions in the primary chamber 68 and in the pressure chamber 71, the check valve 67 opens, so that the pressure chamber 71 is under the fuel pressure of the first pressure accumulator 61 and the pressure medium 65 is hydraulically returned to its starting position.
  • one or more springs can be arranged in rooms 68, 69 and 71.
  • the valve unit 63 is only shown as an example as a 3/2-way valve.
  • the injector 80 shown in FIG. 5 has two pressure lines 82, 83 connected to one another via a check valve 81 for the higher or lower fuel pressure, the control chamber 24 being connected to the pressure line 83.
  • the higher fuel pressure By applying the higher fuel pressure to the nozzle chamber 11 via the pressure line 82, the main injection is pressure-controlled.
  • the lower fuel pressure is applied to the nozzle chamber 11 via the pressure line 83, the pre-injection or post-injection takes place in a stroke-controlled manner.
  • the fuel pressure stored in the pressure accumulator 61 is used as the lower fuel pressure. If necessary, a higher fuel pressure can then be generated from this by means of a local pressure transmission unit 91 , which is arranged in a bypass line 92 of the pressure line 10. Using a valve unit 93 (3/2-way valve) in the bypass line 92, a local pressure booster 94 , which is constructed analogously to the central pressure booster 64, can be switched on.
  • the pressure chamber 95 of the local pressure booster 94 is filled with fuel from the pressure accumulator 61, the check valve 81 preventing the return of compressed fuel back into the pressure accumulator 61.
  • the pressure transmission unit 91 together with the check valve 81 can be located inside the injector 80 (FIG. 6a) or outside (FIG. 6b).
  • FIG. 7 a shows an injection system 100, in which, unlike injection system 60 (FIG. 4), the fuel is stored in the second pressure accumulator 6 under the lower fuel pressure. As in FIG. 6, the higher fuel pressure is then generated for each injector 80 by means of the local pressure translation unit 91.
  • the fuel delivered by the high-pressure pump 2 is stored in the central first pressure accumulator 61 under a pressure of approximately 50 to approximately 200 bar.
  • the pressure chamber 71 of the central pressure booster 64 can also be filled with fuel from the first pressure accumulator 61, as in FIG. 7a, with fuel 3 ', which a fuel pump 2' (feed pump) via a feed line 5 'from a promotes another storage tank 4 'in the pressure chamber 71. Since the high pressure side and the low pressure side of the central pressure translation unit are hydraulically decoupled from one another, different operating materials, for example oil for the low pressure side and fuel for the high pressure side, can also be used for both sides.
  • the injection system 110 of FIG. 8 uses a quantity-controlled two-stage high-pressure pump 111 to generate two different fuel pressures, of which the lower one is stored centrally in the first pressure accumulator 61 and the higher one centrally in the second pressure accumulator 6.
  • the pressure line 83 is constantly connected to the first pressure accumulator 61, while for the main injection the pressure line 82 is connected to the second pressure accumulator 6 via a 3/2-way valve 112.
  • the 3/2-way valve 112 can be arranged inside the injector 80 ( FIG. 8a ) or outside ( FIG. 8b ).
  • a 2/2-way valve 113 can also be provided in the pressure line 82 for switching the higher fuel pressure.
  • the injection system 120 shown in FIG. 9 differs from the injection system 110 only in that a quantity-controlled, single-stage high-pressure pump 2 delivers fuel only into the second pressure accumulator 6, from which fuel is then conveyed into the first pressure accumulator 61.
  • a quantity-controlled, single-stage high-pressure pump 2 delivers fuel only into the second pressure accumulator 6, from which fuel is then conveyed into the first pressure accumulator 61.
  • the lower fuel pressure of approximately 400 bar is maintained in the first pressure accumulator 61.
  • the 3/2-way valve 112 is arranged inside the injector 80 and in Fig. 9b outside, while in Fig. 9c a 2/2-way valve 113 is provided.
  • a two-stage high-pressure pump 2 is used in the injection system 130 shown in FIG. 10 to generate the higher and the lower fuel pressure.
  • the lower fuel pressure is fed into the central pressure accumulator 61, while the higher fuel pressure is generated by energizing the 2/2-way valve 41 and is distributed to the individual injectors 80 via a distributor device 42.
  • the injection system 140 shown in FIG. 11 differs from the injection system 90 (FIG. 6) in that the lower fuel pressure of the pressure accumulator 61 is not allocated to the injectors 80 via a distributor device, but rather each injector 80 via a separate pressure line to the pressure accumulator 61 connected.
  • the local pressure translation unit 91 can be located inside the injector 80 ( FIG. 11a ) or outside ( FIG. 11b ). It is also possible to use piezo actuators instead of one or both solenoid valves. Temperature compensation and possibly a hydraulic coupling must be provided for these piezo actuators. Both the stroke-controlled injection with the lower fuel pressure and the pressure-controlled injection with the higher fuel pressure can be carried out with a piezo actuator instead of a solenoid valve.
  • the metering accuracy of the injection can be improved by the high actuating speed of a piezo actuator. Furthermore, an injection course shaping (in general with the main injection) can be realized. If a piezo actuator is used for the stroke control, an outlet throttle may not be necessary due to the low pressure level that can be switched.
  • the injection system 150 of FIG. 12 like the injection system 110 shown in FIG. 8b, uses two pressure reservoirs 6, 61 for the higher and the lower fuel pressure, wherein, unlike in FIG. 8b, the higher fuel pressure as in FIG. 4 by means of the central pressure translation unit 62 is generated and the higher fuel pressure is distributed centrally to the injectors 80 via the 3/2-way valve 51 and the distributor device 42, as in FIG. 3a.
  • the injection system 160 shown in FIG. 13 differs from the injection system 150 in that it uses the injector 80 shown in FIG. 8a, in which the higher fuel pressure is metered locally via the 3/2-way valve 112.
  • the 3/2-way valve 112 can either be arranged inside the injector housing (FIG. 13a) or, in particular together with the check valve 81, outside (FIG. 13b) .
  • a method of injecting fuel with at least two different fuel pressures via injectors 80 into the combustion chamber of an internal combustion engine takes place with the lower one Fuel pressure stroke-controlled and fuel injection pressure controlled with the higher fuel pressure.
  • Fuel pressure stroke-controlled and fuel injection pressure controlled with the higher fuel pressure are the control room 24 and via a check valve 81 also the nozzle area 11 connected to a low pressure fuel supply, and for a main injection with the higher one Fuel pressure is the nozzle space 11 to the high pressure fuel supply connected.

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)
  • High-Pressure Fuel Injection Pump Control (AREA)

Abstract

In a method for injecting fuel at at least two differently high fuel pressures via injectors into the combustion chamber of an internal combustion engine, the fuel injection at the lower fuel pressure takes place under stroke control, and the fuel injection at the higher fuel pressure takes place under pressure control. For a pre- and/or post-injection and/or a boot injection at the lower fuel pressure, the control chamber and via a check valve the nozzle chamber as well are connected to a low-pressure fuel supply, and that for a main injection at the higher fuel pressure, the nozzle chamber is connected to the high-pressure fuel supply.

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einem Kraftstoffeinspritzverfahren für eine Brennkraftmaschine nach der Gattung des Patentanspruchs 1 sowie von einem Kraftstoffeinspritzsystem nach der Gattung des Patentanspruchs 4. The invention is based on a fuel injection method for an internal combustion engine of the genus Claim 1 and a fuel injection system according to the preamble of claim 4.

Ein derartiges Kraftstoffeinspritzverfahren und -system ist beispielsweise durch die WO 98/09068 bekanntgeworden.Such a fuel injection method and system has become known, for example, from WO 98/09068.

Zum besseren Verständnis der nachfolgenden Beschreibung werden zunächst einige Begriffe näher erläutert: Bei einem druckgesteuerten Kraftstoffeinspritzsystem wird durch den im Düsenraum eines Injektors herrschenden Kraftstoffdruck ein Ventilkörper (z.B. eine Düsennadel) gegen die Wirkung einer Schließkraft aufgesteuert und so die Einspritzöffnung für eine Einspritzung des Kraftstoffes freigegeben. Der Druck, mit dem Kraftstoff aus dem Düsenraum in den Zylinder austritt, wird als Einspritzdruck bezeichnet. Unter einem hubgesteuerten Kraftstoffeinspritzsystem wird im Rahmen der Erfindung verstanden, daß das Öffnen und Schließen der Einspritzöffnung eines Injektors mit Hilfe eines verschieblichen Ventilglieds aufgrund des hydraulischen Zusammenwirkens der Kraftstoffdrücke in einem Düsenraum und in einem Steuerraum erfolgen. Weiterhin ist im folgenden eine Anordnung als zentral bezeichnet, wenn sie gemeinsam für alle Zylinder vorgesehen ist, und als lokal, wenn sie für nur einen einzelnen Zylinder vorgesehen ist.For a better understanding of the following description, a few terms are first explained in more detail: In a pressure-controlled fuel injection system , the fuel pressure prevailing in the nozzle space of an injector opens a valve body (for example a nozzle needle) against the action of a closing force and thus releases the injection opening for an injection of the fuel. The pressure at which fuel exits the nozzle chamber into the cylinder is called the injection pressure. A stroke-controlled fuel injection system is understood in the context of the invention that the opening and closing of the injection opening of an injector take place with the aid of a displaceable valve member due to the hydraulic interaction of the fuel pressures in a nozzle chamber and in a control chamber. Furthermore, an arrangement is referred to below as central if it is intended for all cylinders together and as local if it is intended for only a single cylinder.

Bei dem in der WO 98/09068 beschriebenen Einspritzsystem erfolgen sowohl die Einspritzung mit dem höheren Kraftstoffdruck als auch die Einspritzung mit dem tieferen Kraftstoffdruck hubgesteuert, wobei Steuerraum und Düsenraum miteinander unmittelbar verbunden sind. Da der höhere Einspritzdruck auch im Steuerraum herrscht, sind auch dort entsprechende Anforderungen an Dichtfunktion, Federkräfte und Ventilglied zu erfüllen. Durch die Hubsteuerung ist eine gute Reproduzierbarkeit der Einspritzung mit dem tieferen Kraftstoffdruck möglich. In the injection system described in WO 98/09068 both the injection takes place with the higher fuel pressure as well as the injection with the lower one Fuel pressure is stroke-controlled, with the control chamber and nozzle chamber are directly connected to each other. Because the higher one Injection pressure also prevails in the control room, are there too corresponding requirements for sealing function, spring forces and valve member to meet. Through the stroke control good reproducibility of the injection with the lower one Fuel pressure possible.

Aus der EP 0 711 914 A1 ist ein druckgesteuertes Kraftstoffeinspritzsystem bekannt, bei dem über eine Ventilsteuereinheit entweder der tiefere oder höhere Kraftstoffdruck in den Düsenraum des Injektors geleitet wird. Dort wird durch den Druck ein federbelasteter Ventilkörper von seinem Ventilsitz abgehoben, so daß Kraftstoff aus der Einspritzöffnung austreten kann. Bei druckgesteuerten Einspritzsystemen werden bei der Einspritzung Druckwellen entfacht, die bei der Haupteinspritzung mit dem höheren Kraftstoffdruck zwar gewollt, aber bei der Voreinspritzung mit dem tieferen Kraftstoffdruck einen negativen Einfluß auf das hydraulische Verhalten des Einspritzsystems bei der anschließenden Haupteinspritzung ausüben können.EP 0 711 914 A1 describes a pressure-controlled fuel injection system known, in which a valve control unit either the lower or higher fuel pressure is directed into the injector nozzle area. There becomes a spring-loaded valve body by the pressure lifted its valve seat so that fuel from the Injection port can leak. With pressure-controlled injection systems are pressure waves during injection kindled the main injection with the higher one Fuel pressure is wanted, but during pre-injection with the lower fuel pressure a negative influence on the hydraulic behavior of the injection system the subsequent main injection.

Vorteile der ErfindungAdvantages of the invention

Zur Verbesserung des Einspritzverhaltens werden erfindungsgemäß das Einspritzverfahren gemäß Patentanspruch 1 und die Kraftstoffeinspritzsysteme gemäß Patentanspruch 4 und 8 vorgeschlagen. Erfindungsgemäße Weiterbildungen sind in den Patentansprüchen 2 und 3 sowie 5 bis 9 enthalten.To improve the injection behavior, the invention the injection method according to claim 1 and the fuel injection systems according to claim 4 and 8 suggested. Further developments according to the invention are contained in claims 2 and 3 and 5 to 9.

Erfindungsgemäß werden die Vorteile eines hubgesteuerten und eines druckgesteuerten Einspritzsystems kombiniert. Damit ergeben sich entscheidende Vorteile:

  • flexiblere Vor- und Nacheinspritzung;
  • bessere Dosiermöglichkeiten und gute Reproduzierbarkeit der Vor- und Nacheinspritzung durch eine Hubsteuerung und geringen Einspritzdruck;
  • sehr kleine Baugröße des Injektors, da die Hubsteuerung aufgrund des geringen Druckes als Steuerorgan ein 2/2-Wege-Ventil aufweisen kann;
  • Verwendung von schnell schaltenden Magnetventilen bei geringem Strombedarf;
  • kleiner Einfluß der Bauteiltoleranzen auf die Vor- und Nacheinspritzung;
  • Drucküberhöhung bei der Haupteinspritzung und dreiecksförmiger Einspritzverlauf;
  • geringere Anforderungen an Dichtfunktion, Federkräfte und Ventilglied durch geringeren Druck bei der Vor- und Nacheinspritzung;
  • Wahlmöglichkeit des Einspritzprinzips bei der Haupteinspritzung bei kleinen Einspritzdrücken.
According to the invention, the advantages of a stroke-controlled and a pressure-controlled injection system are combined. This has decisive advantages:
  • more flexible pre and post injection;
  • better dosing options and good reproducibility of pre and post injection thanks to stroke control and low injection pressure;
  • very small size of the injector, since the stroke control can have a 2/2-way valve as a control element due to the low pressure;
  • Use of fast switching solenoid valves with low power consumption;
  • small influence of component tolerances on pre and post injection;
  • Pressure increase in the main injection and triangular injection course;
  • lower demands on sealing function, spring forces and valve member due to lower pressure during pre and post injection;
  • Choice of the injection principle for the main injection at low injection pressures.

Der tiefere Kraftstoffdruck kann auch für die Haupteinspritzung zur Realisierung eines bootförmigen Einspritzverlaufs verwendet werden.The lower fuel pressure can also be used for the main injection to realize a boat-shaped injection process be used.

Weitere Vorteile und vorteilhafte Ausgestaltungen des Gegenstands der Erfindung sind der Beschreibung, der Zeichnung und den Ansprüchen entnehmbar. Further advantages and advantageous configurations of the object the invention are the description, the drawing and removable from the claims.

Zeichnungdrawing

Verschiedene Ausführungsbeispiele von erfindungsgemäßen hub-/druckgesteuerten Kraftstoffeinspritzsystemen sind in der Zeichnung schematisch dargestellt und in der nachfolgenden Beschreibung erläutert. Es zeigen:

Fig. 1
ein erstes Kraftstoffeinspritzsystem für eine Einspritzung mit zwei, unterschiedlich hohen Kraftstoffdrücken, mit einem zentralen Druckspeicher und jeweils einem lokalen Akkumulatorraum für jeden Injektor;
Fig. 2
ein zweites Kraftstoffeinspritzsystem mit einer zentralen Verteilereinrichtung und jeweils einem lokalen Akkumulatorraum für jeden Injektor;
Fig. 3
ein drittes Kraftstoffeinspritzsystem mit einem zentralen Druckspeicher, einer zentralen Verteilereinrichtung und jeweils einem lokalen Akkumulatorraum für jeden Injektor;
Fig. 4
ein viertes Kraftstoffeinspritzsystem mit zwei zentralen Druckspeichern, einem zentralen Druckverstärker und jeweils einem lokalen Druckverstärker für jeden Injektor;
Fig. 5
ein Ausführungsbeispiel eines hub-/druckgesteuerten Injektors;
Fig. 6
ein fünftes Kraftstoffeinspritzsystem mit dem in Fig. 5 gezeigten Injektor, einem zentralen Druckspeicher, einer zentralen Verteilereinrichtung und jeweils einem lokalen Druckverstärker für jeden Injektor;
Fig. 7
ein sechstes Kraftstoffeinspritzsystem mit dem in Fig. 5 gezeigten Injektor, zwei zentralen Druckspeichern und jeweils einem lokalen Druckverstärker für jeden Injektor;
Fig. 8
ein siebtes Kraftstoffeinspritzsystem mit dem in Fig. 5 gezeigten Injektor sowie zwei zentralen Druckspeichern;
Fig. 9
ein achtes Kraftstoffeinspritzsystem mit dem in Fig. 5 gezeigten Injektor sowie zwei zentralen Druckspeichern;
Fig. 10
ein neuntes Kraftstoffeinspritzsystem mit dem in Fig. 5 gezeigten Injektor, einem zentralen Druckspeicher sowie einer zentralen Verteilereinrichtung;
Fig. 11
ein zehntes Kraftstoffeinspritzsystem mit dem in Fig. 5 gezeigten Injektor, einem zentralen Druckspeicher sowie jeweils einem lokalen Druckverstärker für jeden Injektor;
Fig. 12
ein elftes Kraftstoffeinspritzsystem mit dem in Fig. 5 gezeigten Injektor, zwei zentralen Druckspeichern, einem zentralen Druckverstärker sowie einer zentralen Verteilereinrichtung; und
Fig. 13
ein zwölftes Kraftstoffeinspritzsystem mit dem in Fig. 5 gezeigten Injektor, zwei zentralen Druckspeichern sowie einem zentralen Druckverstärker.
Various exemplary embodiments of stroke / pressure-controlled fuel injection systems according to the invention are shown schematically in the drawing and explained in the description below. Show it:
Fig. 1
a first fuel injection system for an injection with two different fuel pressures, with a central pressure accumulator and in each case a local accumulator space for each injector;
Fig. 2
a second fuel injection system with a central distributor device and in each case a local accumulator space for each injector;
Fig. 3
a third fuel injection system with a central pressure accumulator, a central distributor device and in each case a local accumulator space for each injector;
Fig. 4
a fourth fuel injection system with two central pressure accumulators, a central pressure booster and a local pressure booster for each injector;
Fig. 5
an embodiment of a stroke / pressure controlled injector;
Fig. 6
a fifth fuel injection system with the injector shown in FIG. 5, a central pressure accumulator, a central distributor device and in each case a local pressure booster for each injector;
Fig. 7
a sixth fuel injection system with the injector shown in FIG. 5, two central pressure accumulators and one local pressure booster for each injector;
Fig. 8
a seventh fuel injection system with the injector shown in FIG. 5 and two central pressure accumulators;
Fig. 9
an eighth fuel injection system with the injector shown in FIG. 5 and two central pressure accumulators;
Fig. 10
a ninth fuel injection system with the injector shown in Figure 5, a central pressure accumulator and a central distributor device.
Fig. 11
a tenth fuel injection system with the injector shown in FIG. 5, a central pressure accumulator and in each case a local pressure booster for each injector;
Fig. 12
an eleventh fuel injection system with the injector shown in FIG. 5, two central pressure accumulators, a central pressure booster and a central distributor device; and
Fig. 13
a twelfth fuel injection system with the injector shown in FIG. 5, two central pressure accumulators and a central pressure booster.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Bei dem in Fig. 1 dargestellten ersten Ausführungsbeispiel eines hub-/druckgesteuerten Kraftstoffeinspritzsystems 1 fördert eine mengengeregelte Hochdruckpumpe 2 Kraftstoff 3 aus einem Vorratstank 4 mit hohem Druck über eine Förderleitung 5 in einen zentralen Druckspeicher 6 (Hochdruck-Common-Rail), von dem mehrere, der Anzahl einzelner Zylinder entsprechende Hochdruckleitungen 7 zu den einzelnen, in den Brennraum der zu versorgenden Brennkraftmaschine ragenden Injektoren 8 (Einspritzeinrichtung) abführen. In Fig. 1 ist lediglich einer der Injektoren 8 näher dargestellt. Im Druckspeicher 6 kann ein erster höherer Kraftstoffdruck von ca. 300 bar bis 1800 bar gelagert werden.In the example shown in Fig. 1 first embodiment of a lifting / pressure-controlled fuel injection system 1 promotes a quantity-controlled high-pressure pump 2 fuel 3 from a storage tank 4 under high pressure via a delivery line 5 in a central pressure accumulator 6 (high-pressure common rail), from which a plurality Drain the high-pressure lines 7 corresponding to the number of individual cylinders to the individual injectors 8 (injection device) projecting into the combustion chamber of the internal combustion engine to be supplied. In Fig. 1 only one of the injectors 8 is shown in more detail. A first higher fuel pressure of approximately 300 bar to 1800 bar can be stored in the pressure accumulator 6.

Der in der Hochdruckleitung 7 anstehende höhere Kraftstoffdruck wird mittels Bestromens eines 3/2-Wege-Ventils 9 über eine Druckleitung 10 in einen Düsenraum 11 des Injektors 8 geleitet. Die Einspritzung mit dem höheren Kraftstoffdruck (Haupteinspritzung) erfolgt druckgesteuert mit Hilfe eines in einer Führungsbohrung axial verschiebbaren kolbenförmigen Ventilglieds 12 (Düsennadel), dessen konische Ventildichtfläche 13 mit einer Ventilsitzfläche am Injektorgehäuse zusammenwirkt und so die dort vorgesehenen Einspritzöffnungen 14 verschließt. Innerhalb des Düsenraums 11 ist eine in Öffnungsrichtung des Ventilglieds 12 weisende Druckfläche des Ventilgliedes 12 dem dort herrschenden Druck ausgesetzt, wobei sich der Düsenraum 11 über einen Ringspalt zwischen dem Ventilglied 12 und der Führungsbohrung bis an die Ventildichtfläche 13 des Injektors 8 fortsetzt. Durch den im Düsenraum 11 herrschenden Druck wird das die Einspritzöffnungen 14 abdichtende Ventilglied 12 gegen die Wirkung einer Schließkraft (Schließfeder 15) aufgesteuert, wobei der Federraum 16 mittels einer Leckageleitung 17 druckentlastet ist. Durch Umschalten des 3/2-Wege-Ventils 9 zurück in den unbestromten Zustand wird die Haupteinspritzung beendet und die Druckleitung 10 über eine Anschlußleitung 18 und ein auf einen zweiten tieferen Kraftstoffdruck (ca. 300 bar) eingestelltes Druckbegrenzungsventil 19 mit einer Leckageleitung 20 verbunden. Die Leckageleitung 20 dient der Druckentlastung und kann in den Vorratstank 4 zurückführen. Infolge der Umschaltung baut sich der in der Druckleitung 10 und dem Düsenraum 11 zunächst noch herrschende höhere Kraftstoffdruck auf den tieferen Kraftstoffdruck ab, der in einem an die Anschlußleitung 18 angeschlossenen Akkumulatorraum 21 gelagert wird. Dieser tiefere Kraftstoffdruck dient zur Vor- und/oder Nacheinspritzung (HC-Anreicherung zur Abgasnachbehandlung).The higher fuel pressure in the high-pressure line 7 is conducted by energizing a 3/2-way valve 9 via a pressure line 10 into a nozzle chamber 11 of the injector 8. The injection with the higher fuel pressure (main injection) is pressure-controlled with the aid of a piston-shaped valve member 12 (nozzle needle) which is axially displaceable in a guide bore and whose conical valve sealing surface 13 interacts with a valve seat surface on the injector housing and thus closes the injection openings 14 provided there. Within the nozzle space 11, a pressure surface of the valve element 12 pointing in the opening direction of the valve element 12 is exposed to the pressure prevailing there, the nozzle space 11 continuing through an annular gap between the valve element 12 and the guide bore up to the valve sealing surface 13 of the injector 8. Due to the pressure prevailing in the nozzle chamber 11, the valve member 12 sealing the injection openings 14 is opened against the action of a closing force (closing spring 15), the spring chamber 16 being relieved of pressure by means of a leakage line 17 . By switching the 3/2-way valve 9 back into the de-energized state, the main injection is ended and the pressure line 10 is connected to a leakage line 20 via a connecting line 18 and a pressure relief valve 19 set to a second lower fuel pressure (approx. 300 bar). The leakage line 20 serves to relieve pressure and can lead back into the storage tank 4. As a result of the switchover, the higher fuel pressure initially prevailing in the pressure line 10 and the nozzle chamber 11 is reduced to the lower fuel pressure which is stored in an accumulator chamber 21 connected to the connecting line 18. This lower fuel pressure is used for pre and / or post injection (HC enrichment for exhaust gas aftertreatment).

Am Ventilglied 12 greift koaxial zu der Schließfeder 15 ein Druckstück 22 an, das mit seiner der Ventildichtfläche 13 abgewandten Stirnseite 23 einen Steuerraum 24 begrenzt. Der Steuerraum 24 hat von der Anschlußleitung 18 her einen Kraftstoffzulauf 25 mit einer ersten Drossel 26 und einen Kraftstoffablauf zu einer Druckentlastungsleitung 27 mit einer zweiten Drossel 28, die durch ein Steuerorgan in Form eines 2/2-Wege-Ventils 29 mit der Leckageleitung 20 verbindbar ist. Über den Druck im Steuerraum 24 wird das Druckstück 22 in Schließrichtung druckbeaufschlagt. Durch Betätigen (Bestromen) des 2/2-Wege-Ventils 29 kann der Druck im Steuerraum 24 abgebaut werden, so daß in der Folge der in Öffnungsrichtung auf das Ventilglied 12 wirkende Druck im Düsenraum 11 den in Schließrichtung auf das Ventilglied 12 wirkenden Druck übersteigt. Die Ventildichtfläche 13 hebt von der Ventilsitzfläche ab, so daß eine Einspritzung mit dem tieferen Kraftstoffdruck erfolgt. Dabei läßt sich der Entlastungsvorgang des Steuerraums 24 und somit die Hubsteuerung des Ventilglieds 12 über die Dimensionierung der beiden Drosseln 26, 28 beeinflussen. Durch Schließen des 2/2-Wege-Ventils 29 wird diese Einspritzung dann beendet. Die Einspritzung mit dem tieferen Systemdruck kann entweder nach der Haupteinspritzung als Nacheinspritzung oder vor der Haupteinspritzung als Voreinspritzung erfolgen. Sofern der Akkumulatorraum 21 auch nach einer Nacheinspritzung noch ausreichend mit unter Druck stehendem Kraftstoff gefüllt ist, kann dieser Kraftstoff beim nächsten Einspritzzyklus für eine Voreinspritzung genutzt werden, wodurch für jeden Einspritzzyklus eine Vor- und Nacheinspritzung möglich ist. Die Größe des Akkumulatorraums 21 ist an die Erfordernisse der Vor- und Nacheinspritzung angepaßt, wobei die Funktion des Akkumulatorraums 21 auch eine genügend lange Druckleitung erfüllen kann.On the valve member 12, the end face 23 remote from its valve sealing surface 13 engages coaxially to the closing spring 15, a pressing piece 22 to a control chamber 24 delimited. The control chamber 24 has a fuel inlet 25 with a first throttle 26 and a fuel outlet from the connecting line 18 to a pressure relief line 27 with a second throttle 28 , which can be connected to the leakage line 20 by a control element in the form of a 2/2-way valve 29 is. The pressure piece 22 is pressurized in the closing direction by the pressure in the control chamber 24. By actuating (energizing) the 2/2-way valve 29 , the pressure in the control chamber 24 can be reduced, so that as a result the pressure acting on the valve member 12 in the opening direction exceeds the pressure acting on the valve member 12 in the closing direction , The valve sealing surface 13 lifts off from the valve seat surface, so that an injection takes place with the lower fuel pressure. The relief process of the control chamber 24 and thus the stroke control of the valve member 12 can be influenced by the dimensioning of the two throttles 26, 28. This injection is then ended by closing the 2/2-way valve 29. The injection with the lower system pressure can take place either after the main injection as a post-injection or before the main injection as a pre-injection. If the accumulator chamber 21 is still sufficiently filled with pressurized fuel even after a post-injection, this fuel can be used for a pre-injection during the next injection cycle, whereby a pre-injection and post-injection is possible for each injection cycle. The size of the accumulator chamber 21 is adapted to the requirements of the pre-injection and post-injection, the function of the accumulator chamber 21 also being able to fulfill a sufficiently long pressure line.

Die in Fig. 1 insgesamt mit 30 bezeichnete Anordnung aus 3/2-Wege-Ventil 9, Druckbegrenzungsventil 19 und Akkumulatorraum 21 kann entweder innerhalb des Injektorgehäuses (Fig. 1a) oder außerhalb (Fig. 1b) angeordnet sein.The arrangement of 3/2-way valve 9, pressure relief valve 19 and accumulator space 21, designated overall by 30 in FIG. 1, can be arranged either inside the injector housing ( FIG. 1a ) or outside ( FIG. 1b ).

Nachfolgend werden in der Beschreibung zu den weiteren Figuren lediglich die Unterschiede zum Kraftstoffeinspritzsystem nach Fig. 1 behandelt. Identische bzw. funktionsgleiche Bauteile sind mit gleichen Bezugsziffern bezeichnet und werden nicht näher erläutert.The following describes the other figures in the description only the differences to the fuel injection system treated according to Fig. 1. Identical or functionally identical Components are identified by the same reference numbers and are not explained in more detail.

Bei dem in Fig. 2a gezeigten Einspritzsystem 40 ist der zentrale Druckspeicher der Fig. 1 ausgelassen, und der Druckaufbau erfolgt durch Bestromen eines 2/2-Wege-Ventils 41. Die Hochdruckpumpe 2 kann einen Kraftstoffdruck von ca. 300 bis ca. 1600 bar erzeugen und z.B. eine Nockenpumpe sein. Eine zentrale Verteilereinrichtung 42 verteilt diesen Kraftstoffdruck auf die einzelnen Injektoren 43. Hinter der Verteilereinrichtung 42 sind für jeden Injektor 43 noch ein Rückschlagventil 44, das den Kraftstoff in Richtung Injektor 43 durchläßt, und ein bei ca. 300 bar öffnendes Druckbegrenzungsventil 45, das einen Rückfluß von Kraftstoff aus dem Injektor 43 zur Entlastung der Verteilereinrichtung 42 und zum Druckabbau zuläßt, vorgesehen. Rückschlagventil 44 und Druckbegrenzungsventil 45 bilden die insgesamt mit 46 bezeichnete Ventilanordnung. Anders als beim Injektor 8 hat nun auch der Steuerraum 24 des Injektors 43 seinen Kraftstoffzulauf 25 von der Druckleitung 10 her und ist der Akkumulatorraum 47 in der Druckleitung 10 unmittelbar vor dem Düsenraum 11 angeordnet. Außerdem ist der Druck im Steuerraum 24 über ein Druckbegrenzungsventil 48 auf ca. 300 bar begrenzt. Dieses Druckbegrenzungsventil 48 kann auch im 2/2-Wege-Ventil 29 bzw. in einem entsprechenden Magnetventil integriert sein.In the injection system 40 shown in FIG. 2a , the central pressure accumulator of FIG. 1 is omitted, and the pressure is built up by energizing a 2/2-way valve 41. The high-pressure pump 2 can have a fuel pressure of approximately 300 to approximately 1600 bar generate and be a cam pump, for example. A central distributor device 42 distributes this fuel pressure to the individual injectors 43 . Behind the distributor device 42 there is a non-return valve 44 for each injector 43, which allows the fuel to flow in the direction of the injector 43, and a pressure relief valve 45 that opens at approx. 300 bar, which allows fuel to flow back from the injector 43 to relieve the distributor device 42 and Allows pressure reduction, provided. Check valve 44 and pressure relief valve 45 form the overall valve arrangement designated 46 . Unlike the injector 8, the control chamber 24 of the injector 43 now also has its fuel inlet 25 from the pressure line 10 and the accumulator chamber 47 is arranged in the pressure line 10 directly in front of the nozzle chamber 11. In addition, the pressure in the control chamber 24 is limited to approximately 300 bar via a pressure limiting valve 48 . This pressure limiting valve 48 can also be integrated in the 2/2-way valve 29 or in a corresponding solenoid valve.

Durch die Ventilanordnung 46 steht der im Injektor 43 vorhandene Kraftstoff bei nichtbestromtem 2/2-Wege-Ventil 41 unter dem tieferen Kraftstoffdruck. Durch Öffnen (Bestromen) des 2/2-Wege-Ventils 29 erfolgt hubgesteuert die Voreinspritzung aus dem lokalen Akkumulator 47. Wird durch Bestromen des 2/2-Wege-Ventils 41 der höhere Systemdruck aktiviert, so steigt der Druck im Düsenraum 11 und im Steuerraum 24 an, so daß das Druckbegrenzungsventil 48 öffnet und der Druck dort auf geringem Niveau begrenzt ist. Durch den höheren Druck im Düsenraum 11 wird das Ventilglied 12 druckgesteuert aufgesteuert. Bei Deaktivierung des höheren Kraftstoffdruckes sinkt der Druck im Injektor 43 über das Druckbegrenzungsventil 45 auf den tieferen Kraftstoffdruck ab, so daß die Hubsteuerung wieder aktiv wird und das Ventilglied 12 schließt.The valve arrangement 46 provides the one present in the injector 43 Fuel when the 2/2-way valve 41 is not energized under the lower fuel pressure. By opening (energizing) of the 2/2-way valve 29 is pre-injected in a stroke-controlled manner from the local accumulator 47. Is by Energize the 2/2-way valve 41 the higher system pressure activated, the pressure in the nozzle chamber 11 and in increases Control chamber 24 so that the pressure relief valve 48th opens and the pressure there is limited to a low level is. Due to the higher pressure in the nozzle chamber 11, the valve member 12 open pressure controlled. When deactivated the higher the fuel pressure, the pressure in the injector drops 43 via the pressure relief valve 45 to the lower one Fuel pressure down, so that the stroke control is active again is and the valve member 12 closes.

Im Ausführungsbeispiel nach Fig. 2b ist die den Druck begrenzende Ventilanordnung 46a durch ein 3/2-Wege-Ventil 49 und ein bei ca. 300 bar öffnendes Druckbegrenzungsventil 45a gebildet. Für die Haupteinspritzung wird bei aktiviertem höheren Kraftstoffdruck die Druckleitung 10 über das 3/2-Wege-Ventil 49 mit der Verteilereinrichtung 42 verbunden. Am Ende der Haupteinspritzung wird dann durch Umschalten des 3/2-Wege-Ventils 49 der im Injektor 43 herrschende Druck über das Druckbegrenzungsventil 45a auf den tieferen Kraftstoffdruck für eine Vor- und/oder Nacheinspritzung abgebaut.In the exemplary embodiment according to FIG. 2b , the pressure-limiting valve arrangement 46a is formed by a 3/2-way valve 49 and a pressure-limiting valve 45a that opens at approximately 300 bar. For the main injection, when the higher fuel pressure is activated, the pressure line 10 is connected to the distributor device 42 via the 3/2-way valve 49. At the end of the main injection, by switching the 3/2-way valve 49, the pressure prevailing in the injector 43 is reduced to the lower fuel pressure for a pre-injection and / or post-injection via the pressure relief valve 45a.

Das Einspritzsystem 50 der Fig. 3 verwendet, anders als das Einspritzsystem 40, einen zentralen Druckspeicher 6 für den höheren Kraftstoffdruck. Über ein 3/2-Wege-Ventil 51 wird die Verteilereinrichtung 42 entweder mit dem Druckspeicher 6 verbunden oder auf Leckage 52 zurückgeschaltet, um am Ende der Haupteinspritzung die Verteilereinrichtung 42 zu entlasten. In Fig. 3a ist die Ventilanordnung 46a und in Fig. 3b die Ventilanordnung 46 vorgesehen. 3, unlike injection system 40, uses a central pressure accumulator 6 for the higher fuel pressure. Via a 3/2-way valve 51, the distributor device 42 is either connected to the pressure accumulator 6 or switched back to leakage 52 in order to relieve the distributor device 42 at the end of the main injection. The valve arrangement 46a is provided in FIG. 3a and the valve arrangement 46 in FIG. 3b .

Das in Fig. 4 gezeigte Einspritzsystem 60 entspricht mit Ausnahme der Erzeugung des höheren Kraftstoffdruckes dem Einspritzsystem 1. Die Hochdruckpumpe 2 fördert Kraftstoff in einen ersten zentralen Druckspeicher 61 (Niederdruck-Common-Rail). Der dort unter einem Druck von ca. 200 bis 600 bar gelagerte Kraftstoff wird mittels einer zentralen Druckübersetzungseinheit 62 auf den höheren Kraftstoffdruck (ca. 600 bis ca. 1800 bar) komprimiert und im zweiten zentralen Druckspeicher 6 gelagert. Die Druckübersetzungseinheit 62 umfaßt eine Ventileinheit 63 zur Druckübersetzungsansteuerung, einen Druckübersetzer 64 mit einem Druckmittel 65 in Form eines verschieblichen Kolbenelements sowie zwei Rückschlagventile 66 und 67. Das Druckmittel 65 kann einenends mit Hilfe der Ventileinheit 63 an den ersten Druckspeicher 61 angeschlossen werden, so daß es durch den in einer Primärkammer 68 befindlichen Kraftstoff einenends druckbeaufschlagt wird. Ein Differenzraum 69 ist mittels einer Leckageleitung 70 druckentlastet, so daß das Druckmittel 65 zur Verringerung des Volumens einer Druckkammer 71 in Kompressionsrichtung verschoben werden kann. Dadurch wird der in der Druckkammer 71 befindliche Kraftstoff entsprechend dem Flächenverhältnis von Primärkammer 68 und Druckkammer 71 auf den höheren Kraftstoffdruck verdichtet und dem zweiten Druckspeicher 6 zugeführt. Das Rückschlagventil 66 verhindert den Rückfluß von komprimiertem Kraftstoff aus dem zweiten Druckspeicher 6. Wird die Primärkammer 68 mit Hilfe der Ventileinheit 63 an eine Leckageleitung 72 angeschlossen, so erfolgen die Rückstellung des Druckmittels 65 und die Wiederbefüllung der Druckkammer 71, die über das Rückschlagventil 67 an den ersten Druckspeicher 61 angeschlossen ist. Aufgrund der Druckverhältnisse in der Primärkammer 68 und in der Druckkammer 71 öffnet das Rückschlagventil 67, so daß die Druckkammer 71 unter dem Kraftstoffdruck des ersten Druckspeichers 61 steht und das Druckmittel 65 hydraulisch in seine Ausgangsstellung zurückgefahren wird. Zur Verbesserung des Rückstellverhaltens können eine oder mehrere Federn in den Räumen 68, 69 und 71 angeordnet sein. Im dargestellten Ausführungsbeispiel ist die Ventileinheit 63 lediglich beispielhaft als 3/2-Wege-Ventil dargestellt.The injection system 60 shown in FIG. 4 corresponds to the injection system 1 with the exception of the generation of the higher fuel pressure. The high-pressure pump 2 delivers fuel into a first central pressure accumulator 61 (low-pressure common rail). The fuel stored there under a pressure of approx. 200 to 600 bar is compressed to the higher fuel pressure (approx. 600 to approx. 1800 bar) by means of a central pressure translation unit 62 and stored in the second central pressure accumulator 6. The pressure booster unit 62 comprises a valve unit 63 for pressure booster control, a pressure booster 64 with a pressure medium 65 in the form of a displaceable piston element, and two check valves 66 and 67 . The pressure medium 65 can be connected at one end with the aid of the valve unit 63 to the first pressure accumulator 61, so that it is pressurized at one end by the fuel in a primary chamber 68 . A differential space 69 is relieved of pressure by means of a leakage line 70 , so that the pressure medium 65 can be displaced in the compression direction in order to reduce the volume of a pressure chamber 71. As a result, the fuel located in the pressure chamber 71 is compressed to the higher fuel pressure in accordance with the area ratio of the primary chamber 68 and the pressure chamber 71 and supplied to the second pressure accumulator 6. The check valve 66 prevents the backflow of compressed fuel from the second pressure accumulator 6. If the primary chamber 68 is connected to a leakage line 72 with the aid of the valve unit 63, the pressure medium 65 is reset and the pressure chamber 71 is refilled, via the check valve 67 the first pressure accumulator 61 is connected. Due to the pressure conditions in the primary chamber 68 and in the pressure chamber 71, the check valve 67 opens, so that the pressure chamber 71 is under the fuel pressure of the first pressure accumulator 61 and the pressure medium 65 is hydraulically returned to its starting position. To improve the resetting behavior, one or more springs can be arranged in rooms 68, 69 and 71. In the exemplary embodiment shown, the valve unit 63 is only shown as an example as a 3/2-way valve.

Der in Fig. 5 gezeigte Injektor 80 weist zwei über ein Rückschlagventil 81 miteinander verbundene Druckleitungen 82, 83 für den höheren bzw. tieferen Kraftstoffdruck auf, wobei der Steuerraum 24 an die Druckleitung 83 angeschlossen ist. Indem der Düsenraum 11 über die Druckleitung 82 mit dem höheren Kraftstoffdruck beaufschlagt wird, erfolgt die Haupteinspritzung druckgesteuert. Wenn der Düsenraum 11 über die Druckleitung 83 mit dem tieferen Kraftstoffdruck beaufschlagt wird, erfolgt hubgesteuert die Voroder Nacheinspritzung.The injector 80 shown in FIG. 5 has two pressure lines 82, 83 connected to one another via a check valve 81 for the higher or lower fuel pressure, the control chamber 24 being connected to the pressure line 83. By applying the higher fuel pressure to the nozzle chamber 11 via the pressure line 82, the main injection is pressure-controlled. When the lower fuel pressure is applied to the nozzle chamber 11 via the pressure line 83, the pre-injection or post-injection takes place in a stroke-controlled manner.

Bei dem Einspritzsystem 90 der Fig. 6 wird anders als beim Einspritzsystem 60 (Fig. 4) der im Druckspeicher 61 gelagerte Kraftstoffdruck als tieferer Kraftstoffdruck genutzt. Aus diesem kann dann bei Bedarf auch ein höherer Kraftstoffdruck mittels einer lokalen Druckübersetzungseinheit 91 erzeugt werden, die in einer Bypaßleitung 92 der Druckleitung 10 angeordnet ist. Mittels einer Ventileinheit 93 (3/2-Wegeventil) in der Bypaßleitung 92 kann ein lokaler Druckübersetzer 94, der analog dem zentralen Druckübersetzer 64 aufgebaut ist, zugeschaltet werden. Die Druckkammer 95 des lokalen Druckübersetzers 94 wird mit Kraftstoff aus dem Druckspeicher 61 befüllt, wobei das Rückschlagventil 81 den Rücklauf von komprimiertem Kraftstoff zurück in den Druckspeicher 61 verhindert. Die Druckübersetzungseinheit 91 samt Rückschlagventil 81 kann sich innerhalb des Injektors 80 (Fig. 6a) oder außerhalb (Fig. 6b) befinden.In the injection system 90 of FIG. 6 , unlike the injection system 60 (FIG. 4), the fuel pressure stored in the pressure accumulator 61 is used as the lower fuel pressure. If necessary, a higher fuel pressure can then be generated from this by means of a local pressure transmission unit 91 , which is arranged in a bypass line 92 of the pressure line 10. Using a valve unit 93 (3/2-way valve) in the bypass line 92, a local pressure booster 94 , which is constructed analogously to the central pressure booster 64, can be switched on. The pressure chamber 95 of the local pressure booster 94 is filled with fuel from the pressure accumulator 61, the check valve 81 preventing the return of compressed fuel back into the pressure accumulator 61. The pressure transmission unit 91 together with the check valve 81 can be located inside the injector 80 (FIG. 6a) or outside (FIG. 6b).

Fig. 7a zeigt ein Einspritzsystem 100, bei dem anders als beim Einspritzsystem 60 (Fig. 4) der Kraftstoff im zweiten Druckspeicher 6 unter dem tieferen Kraftstoffdruck gelagert ist. Wie in Fig. 6 wird dann für jeden Injektor 80 mittels der lokalen Druckübersetzungseinheit 91 der höhere Kraftstoffdruck erzeugt. Im zentralen ersten Druckspeicher 61 ist der von der Hochdruckpumpe 2 geförderte Kraftstoff unter einem Druck von ca. 50 bis ca. 200 bar gelagert. Wie Fig. 7b zeigt, kann die Druckkammer 71 des zentralen Druckübersetzers 64 anstatt wie in Fig. 7a mit Kraftstoff aus dem ersten Druckspeicher 61 auch mit Kraftstoff 3' befüllt werden, den eine Kraftstoffpumpe 2' (Förderpumpe) über eine Förderleitung 5' aus einem weiteren Vorratstank 4' in die Druckkammer 71 fördert. Da die Hochdruckseite und die Niederdruckseite der zentralen Druckübersetzungseinheit voneinander hydraulisch entkoppelt sind, können für beide Seiten auch unterschiedliche Betriebsstoffe, z.B. Öl für die Niederdruckseite und Kraftstoff für die Hochdruckseite, verwendet werden. FIG. 7 a shows an injection system 100, in which, unlike injection system 60 (FIG. 4), the fuel is stored in the second pressure accumulator 6 under the lower fuel pressure. As in FIG. 6, the higher fuel pressure is then generated for each injector 80 by means of the local pressure translation unit 91. The fuel delivered by the high-pressure pump 2 is stored in the central first pressure accumulator 61 under a pressure of approximately 50 to approximately 200 bar. As FIG. 7b shows, the pressure chamber 71 of the central pressure booster 64 can also be filled with fuel from the first pressure accumulator 61, as in FIG. 7a, with fuel 3 ', which a fuel pump 2' (feed pump) via a feed line 5 'from a promotes another storage tank 4 'in the pressure chamber 71. Since the high pressure side and the low pressure side of the central pressure translation unit are hydraulically decoupled from one another, different operating materials, for example oil for the low pressure side and fuel for the high pressure side, can also be used for both sides.

Das Einspritzsystem 110 der Fig. 8 verwendet eine mengengeregelte zweistufige Hochdruckpumpe 111 zur Erzeugung von zwei unterschiedlich hohen Kraftstoffdrücken, von denen der tiefere zentral im ersten Druckspeicher 61 und der höhere zentral im zweiten Druckspeicher 6 gespeichert werden. Die Druckleitung 83 ist ständig an den ersten Druckspeicher 61 angeschlossen, während für die Haupteinspritzung die Druckleitung 82 über ein 3/2-Wege-Ventil 112 mit dem zweiten Druckspeicher 6 verbunden wird. Bei unbestromtem 3/2-Wege-Ventil 112 ist die Druckleitung 82 mit dem ersten Druckspeicher 61 verbunden. Das 3/2-Wege-Ventil 112 kann innerhalb des Injektors 80 (Fig. 8a) oder außerhalb (Fig. 8b) angeordnet sein. Wie in Fig. 8c gezeigt, kann zum Schalten des höheren Kraftstoffdruckes in der Druckleitung 82 auch ein 2/2-Wege-Ventil 113 vorgesehen sein.The injection system 110 of FIG. 8 uses a quantity-controlled two-stage high-pressure pump 111 to generate two different fuel pressures, of which the lower one is stored centrally in the first pressure accumulator 61 and the higher one centrally in the second pressure accumulator 6. The pressure line 83 is constantly connected to the first pressure accumulator 61, while for the main injection the pressure line 82 is connected to the second pressure accumulator 6 via a 3/2-way valve 112. When the 3/2-way valve 112 is not energized, the pressure line 82 is connected to the first pressure accumulator 61. The 3/2-way valve 112 can be arranged inside the injector 80 ( FIG. 8a ) or outside ( FIG. 8b ). As shown in FIG. 8c , a 2/2-way valve 113 can also be provided in the pressure line 82 for switching the higher fuel pressure.

Das in Fig. 9 gezeigte Einspritzsystem 120 unterscheidet sich vom Einspritzsystem 110 lediglich dadurch, daß eine mengengeregelte einstufige Hochdruckpumpe 2 Kraftstoff nur in den zweiten Druckspeicher 6 fördert, aus dem dann Kraftstoff in den ersten Druckspeicher 61 gefördert wird. Durch Regelung seiner Kraftstoffzufuhr mittels eines 2/2-Wegventils 121 wird im ersten Druckspeicher 61 der tiefere Kraftstoffdruck von ca. 400 bar aufrechterhalten. In Fig. 9a ist das 3/2-Wege-Ventil 112 innerhalb des Injektors 80 und in Fig. 9b außerhalb angeordnet, während in Fig. 9c ein 2/2-Wege-Ventil 113 vorgesehen ist.The injection system 120 shown in FIG. 9 differs from the injection system 110 only in that a quantity-controlled, single-stage high-pressure pump 2 delivers fuel only into the second pressure accumulator 6, from which fuel is then conveyed into the first pressure accumulator 61. By regulating its fuel supply by means of a 2/2-way valve 121 , the lower fuel pressure of approximately 400 bar is maintained in the first pressure accumulator 61. In Fig. 9a , the 3/2-way valve 112 is arranged inside the injector 80 and in Fig. 9b outside, while in Fig. 9c a 2/2-way valve 113 is provided.

Anders als beim Einspritzsystem 110 nach Fig. 8b wird bei dem in Fig. 10 gezeigten Einspritzsystem 130 eine zweistufige Hochdruckpumpe 2 zum Erzeugen des höheren und des tieferen Kraftstoffdrucks verwendet. Der tiefere Kraftstoffdruck wird in den zentralen Druckspeicher 61 gefördert, während der höhere Kraftstoffdruck durch Bestromen des 2/2-Wege-Ventils 41 erzeugt und über eine Verteilereinrichtung 42 auf die einzelnen Injektoren 80 verteilt wird.In contrast to the injection system 110 according to FIG. 8b, a two-stage high-pressure pump 2 is used in the injection system 130 shown in FIG. 10 to generate the higher and the lower fuel pressure. The lower fuel pressure is fed into the central pressure accumulator 61, while the higher fuel pressure is generated by energizing the 2/2-way valve 41 and is distributed to the individual injectors 80 via a distributor device 42.

Das in Fig. 11 gezeigte Einspritzsystem 140 unterscheidet sich von dem Einspritzsystem 90 (Fig. 6) dadurch, daß der tiefere Kraftstoffdruck des Druckspeichers 61 den Injektoren 80 nicht über eine Verteilereinrichtung zugeteilt wird, sondern jeder Injektor 80 über eine eigene Druckleitung an den Druckspeicher 61 angeschlossen ist. Die lokale Druckübersetzungseinheit 91 kann sich innerhalb des Injektors 80 (Fig. 11a) oder außerhalb (Fig. 11b) befinden. Außerdem ist es möglich, anstelle eines oder beider Magnetventile Piezosteller zu verwenden. Für diese Piezosteller ist ein Temperaturausgleich und evtl. eine hydraulische Kopplung vorzusehen. Es kann sowohl die hubgesteuerte Einspritzung mit dem tieferen Kraftstoffdruck als auch die druckgesteuerte Einspritzung mit dem höheren Kraftstoffdruck mit einem Piezosteller anstatt eines Magnetventils ausgeführt werden. Durch die hohe Stellgeschwindigkeit eines Piezostellers kann die Zumeßgenauigkeit der Einspritzung verbessert werden. Weiterhin kann eine Einspritzverlaufsformung (im allgemeinen bei der Haupteinspritzung) realisiert werden. Bei Verwendung eines Piezostellers für die Hubsteuerung kann evtl. wegen des geringen zu schaltenden Druckniveaus auf eine Ablaufdrossel verzichtet werden.The injection system 140 shown in FIG. 11 differs from the injection system 90 (FIG. 6) in that the lower fuel pressure of the pressure accumulator 61 is not allocated to the injectors 80 via a distributor device, but rather each injector 80 via a separate pressure line to the pressure accumulator 61 connected. The local pressure translation unit 91 can be located inside the injector 80 ( FIG. 11a ) or outside ( FIG. 11b ). It is also possible to use piezo actuators instead of one or both solenoid valves. Temperature compensation and possibly a hydraulic coupling must be provided for these piezo actuators. Both the stroke-controlled injection with the lower fuel pressure and the pressure-controlled injection with the higher fuel pressure can be carried out with a piezo actuator instead of a solenoid valve. The metering accuracy of the injection can be improved by the high actuating speed of a piezo actuator. Furthermore, an injection course shaping (in general with the main injection) can be realized. If a piezo actuator is used for the stroke control, an outlet throttle may not be necessary due to the low pressure level that can be switched.

Das Einspritzsystem 150 der Fig. 12 verwendet wie das in Fig. 8b gezeigte Einspritzsystem 110 zwei Druckspeicher 6, 61 für den höheren und den tieferen Kraftstoffdruck, wobei anders als in Fig. 8b der höhere Kraftstoffdruck wie in Fig. 4 mittels der zentralen Druckübersetzungseinheit 62 erzeugt und der höhere Kraftstoffdruck wie in Fig. 3a zentral über das 3/2-Wege-Ventil 51 und die Verteilereinrichtung 42 auf die Injektoren 80 verteilt wird.The injection system 150 of FIG. 12 , like the injection system 110 shown in FIG. 8b, uses two pressure reservoirs 6, 61 for the higher and the lower fuel pressure, wherein, unlike in FIG. 8b, the higher fuel pressure as in FIG. 4 by means of the central pressure translation unit 62 is generated and the higher fuel pressure is distributed centrally to the injectors 80 via the 3/2-way valve 51 and the distributor device 42, as in FIG. 3a.

Das in Fig. 13 gezeigte Einspritzsystem 160 unterscheidet sich von dem Einspritzsystem 150 durch die Verwendung des in Fig. 8a gezeigten Injektors 80, bei dem der höhere Kraftstoffdruck lokal über das 3/2-Wege-Ventil 112 zugemessen wird. Das 3/2-Wege-Ventil 112 kann entweder innerhalb des Injektorgehäuses (Fig. 13a) oder, insbesondere zusammen mit dem Rückschlagventil 81, außerhalb (Fig. 13b) angeordnet sein.The injection system 160 shown in FIG. 13 differs from the injection system 150 in that it uses the injector 80 shown in FIG. 8a, in which the higher fuel pressure is metered locally via the 3/2-way valve 112. The 3/2-way valve 112 can either be arranged inside the injector housing (FIG. 13a) or, in particular together with the check valve 81, outside (FIG. 13b) .

Abschließend wird noch darauf hingewiesen, daß der tiefere Kraftstoffdruck auch für die Haupteinspritzung zur Realisierung eines bootförmigen Einspritzverlaufs verwendet werden kann.Finally, it is pointed out that the lower one Fuel pressure also for the main injection for realization a boat-shaped injection course used can be.

Bei einem Verfahren zum Einspritzen von Kraftstoff mit mindestens zwei unterschiedlich hohen Kraftstoffdrücken über Injektoren 80 in den Brennraum einer Brennkraftmaschine erfolgt die Kraftstoffeinspritzung mit dem tieferen Kraftstoffdruck hubgesteuert und die Kraftstoffeinspritzung mit dem höheren Kraftstoffdruck druckgesteuert. Für eine Vor- und/oder Nacheinspritzung und/oder eine Bootinjektion mit dem tieferen Kraftstoffdruck sind der Steuerraum 24 und über ein Rückschlagventil 81 auch der Düsenraum 11 an eine Niederdruckkraftstoffversorgung angeschlossen, und für eine Haupteinspritzung mit dem höheren Kraftstoffdruck ist der Düsenraum 11 an die Hochdruckkraftstoffversorgung angeschlossen.In a method of injecting fuel with at least two different fuel pressures via injectors 80 into the combustion chamber of an internal combustion engine the fuel injection takes place with the lower one Fuel pressure stroke-controlled and fuel injection pressure controlled with the higher fuel pressure. For a pre-injection and / or post-injection and / or a boat injection with the lower fuel pressure are the control room 24 and via a check valve 81 also the nozzle area 11 connected to a low pressure fuel supply, and for a main injection with the higher one Fuel pressure is the nozzle space 11 to the high pressure fuel supply connected.

Claims (9)

  1. Method for injecting fuel into the combustion chamber of an internal combustion engine at at least two different fuel pressures via injectors (8; 43; 80), the fuel being injected at the lower fuel pressure on a stroke-controlled basis, characterized in that the fuel is injected at the higher fuel pressure on a pressure-controlled basis.
  2. Injection method according to Claim 1, characterized in that, after the injection of fuel at the higher fuel pressure, the fuel pressure in the injector (8; 43) is reduced to the lower fuel pressure and is locally stored for at least one fuel injection process at the lower fuel pressure.
  3. Injection method according to Claim 1 or 2, characterized in that pressure control is performed independently of stroke control.
  4. Fuel injection system (1; 40; 50; 60) for an internal combustion engine, in which fuel can be injected into the combustion chamber of the internal combustion engine at two different fuel pressures via stroke-controlled injectors (8; 43; 80), each injector (8; 43; 80) having in each case one piston-shaped valve element (12) which can be moved axially in a guide hole, is designed to seal an injection opening (14), is passed through a nozzle space (11) which is connected continuously to the guide hole, and can have the pressure formed in a control space (24) applied to it in the direction of the injection opening (14) at its end which is remote from the injection opening (14), and the said injector (8; 43; 80) also having a stroke pressure control member (29) for relieving the pressure in the control space (24), it being possible to connect the nozzle space (11) and the control space (24) to a fuel supply system, in particular for carrying out the injection method according to one of Claims 1 to 3, characterized in that, for a main injection process at the higher fuel pressure, the nozzle space (11) is connected to a high-pressure fuel supply system, and in that, for a pre-injection and/or after-injection process and/or a boot injection process at the lower fuel pressure, the nozzle space (11) and the control space (24) are connected to an accumulator space (21; 47) which is filled during or after the main injection process and is relieved to the lower fuel pressure prior to the pre-injection or after-injection process.
  5. Fuel injection system according to Claim 4, characterized by a device (9) which connects the nozzle space (11) either to the high-pressure fuel supply system or to the accumulator space (21).
  6. Fuel injection system according to Claim 5, characterized in that the accumulator space (21) is connected to a pressure-limiting valve (19) which is set to the lower fuel pressure.
  7. Fuel injection system according to Claim 4, characterized in that the accumulator space (47) is connected continuously to the nozzle space (11) and the control space (24).
  8. Fuel injection system (1; 40; 50; 60) for an internal combustion engine, in which fuel can be injected into the combustion chamber of the internal combustion engine at two different fuel pressures via stroke-controlled injectors (8; 43; 80), each injector (8; 43; 80) having in each case one piston-shaped valve element (12) which can be moved axially in a guide hole, is designed to seal an injection opening (14), is passed through a nozzle space (11) which is connected continuously to the guide hole, and can have the pressure formed in a control space (24) applied to it in the direction of the injection opening (14) at its end which is remote from the injection opening (14), and said injector (8; 43; 80) also having a stroke pressure control member (2/2-way valve 29) for relieving the pressure in the control space (24), it being possible to connect the nozzle space (11) and the control space (24) to a fuel supply system, in particular for carrying out the injection method according to one of Claims 1 to 3, characterized in that, for a pre-injection and/or after-injection process and/or a boot injection process at the lower fuel pressure, the control space (24) and, via a non-return valve (81), also the nozzle space (11) are connected to a low-pressure fuel supply system, and in that, for a main injection process at the higher fuel pressure, the nozzle space (11) is connected to the high-pressure fuel supply system.
  9. Fuel injection system according to one of Claims 4 to 8, characterized in that the pressure surfaces of the valve element (12) which are provided in the nozzle space (11) and in the control space (24) are matched to one another in such a way that the valve element (12) opens on a pressure-controlled basis independently of the position of the stroke pressure control member.
EP00958207A 1999-08-20 2000-08-02 Combined stroke/pressure controlled fuel injection method and system for an internal combustion engine Expired - Lifetime EP1125049B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19939421 1999-08-20
DE19939421A DE19939421A1 (en) 1999-08-20 1999-08-20 Combined stroke / pressure controlled fuel injection method and system for an internal combustion engine
PCT/DE2000/002577 WO2001014713A1 (en) 1999-08-20 2000-08-02 Combined stroke/pressure controlled fuel injection method and system for an internal combustion engine

Publications (2)

Publication Number Publication Date
EP1125049A1 EP1125049A1 (en) 2001-08-22
EP1125049B1 true EP1125049B1 (en) 2004-11-03

Family

ID=7918956

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00958207A Expired - Lifetime EP1125049B1 (en) 1999-08-20 2000-08-02 Combined stroke/pressure controlled fuel injection method and system for an internal combustion engine

Country Status (6)

Country Link
US (1) US6491017B1 (en)
EP (1) EP1125049B1 (en)
JP (1) JP2003507639A (en)
AT (1) ATE281597T1 (en)
DE (2) DE19939421A1 (en)
WO (1) WO2001014713A1 (en)

Families Citing this family (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19939422A1 (en) * 1999-08-20 2001-03-01 Bosch Gmbh Robert Fuel injection system for an internal combustion engine
DE10112154A1 (en) * 2001-03-14 2002-09-26 Bosch Gmbh Robert Fuel injection system
DE10112432A1 (en) * 2001-03-15 2002-09-19 Bosch Gmbh Robert Fuel injection device for internal combustion engines
DE10115396A1 (en) * 2001-03-29 2002-10-10 Bosch Gmbh Robert Fuel injection device for internal combustion engines
DE10123993A1 (en) * 2001-05-17 2002-11-21 Bosch Gmbh Robert Fuel injection device has pressure maintaining valve between working cavity of pump and first control valve
DE10123995A1 (en) * 2001-05-17 2002-11-21 Bosch Gmbh Robert Fuel injection device has third electrically operated control valve to control second connection between pump working cavity and relief cavity
DE10146745A1 (en) * 2001-09-22 2003-04-10 Bosch Gmbh Robert Fuel injection device for an internal combustion engine
DE10154802A1 (en) * 2001-11-08 2003-05-22 Bosch Gmbh Robert Fuel injection device for an internal combustion engine
DE10205749A1 (en) * 2002-02-12 2003-08-21 Bosch Gmbh Robert Fuel injection device for an internal combustion engine
US7278593B2 (en) * 2002-09-25 2007-10-09 Caterpillar Inc. Common rail fuel injector
JP4308487B2 (en) * 2002-07-11 2009-08-05 株式会社豊田中央研究所 Fuel injection method in fuel injection device
DE10260775A1 (en) 2002-12-23 2004-07-01 Daimlerchrysler Ag Fuel supply system for internal combustion engines with direct injection
AU2003211017A1 (en) * 2003-02-12 2004-09-06 Robert Bosch Gmbh Fuel injector pump system with high pressure post injection
DE102004010760A1 (en) * 2004-03-05 2005-09-22 Robert Bosch Gmbh Fuel injection device for internal combustion engines with Nadelhubdämpfung
JP4196895B2 (en) * 2004-07-12 2008-12-17 株式会社デンソー Fuel injection device
DE102004062073B4 (en) * 2004-12-23 2015-08-13 Continental Automotive Gmbh Method and device for compensation of bounce effects in a piezo-controlled injection system of an internal combustion engine
US7334570B2 (en) * 2005-04-01 2008-02-26 Achates Power, Inc. Common rail fuel injection system with accumulator injectors
EP1717434A1 (en) * 2005-04-28 2006-11-02 Delphi Technologies, Inc. Improvements relating to fuel injection systems
US7588012B2 (en) * 2005-11-09 2009-09-15 Caterpillar Inc. Fuel system having variable injection pressure
US7398763B2 (en) 2005-11-09 2008-07-15 Caterpillar Inc. Multi-source fuel system for variable pressure injection
US8100110B2 (en) * 2005-12-22 2012-01-24 Caterpillar Inc. Fuel injector with selectable intensification
US7431017B2 (en) * 2006-05-24 2008-10-07 Caterpillar Inc. Multi-source fuel system having closed loop pressure control
US7392791B2 (en) * 2006-05-31 2008-07-01 Caterpillar Inc. Multi-source fuel system for variable pressure injection
US7353800B2 (en) * 2006-05-24 2008-04-08 Caterpillar Inc. Multi-source fuel system having grouped injector pressure control
DE102006039265A1 (en) * 2006-08-22 2008-02-28 Volkswagen Ag Fuel injection device for internal combustion engine, particularly motor vehicle, has effective surface which converts pressure in control area of injector into force in closing direction of injecting piston
DE102006039263A1 (en) 2006-08-22 2008-03-06 Volkswagen Ag Fuel injector
NL2002384C2 (en) * 2008-03-03 2011-04-04 Vialle Alternative Fuel Systems Bv DEVICE AND METHOD FOR A COMBUSTION ENGINE WITH DIRECT INJECTION WITH TWO FUELS.
EP2341234A3 (en) * 2009-12-31 2012-02-22 Indopar B.V. Direct injection bi-fuel system for combustion engines
NL2006992C2 (en) 2011-06-24 2013-01-02 Indopar B V Method of switching from a liquefied gas fuel to a liquid fuel being provided to a direct injection combustion engine, and direct injection bi-fuel system for such an engine.
KR20130027996A (en) * 2011-09-08 2013-03-18 바르질라 스위츠랜드 리미티드 Fuel injection system for an internal combustion engine, method for injecting fuel, as well as an internal combustion engine

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3217887A1 (en) * 1981-05-15 1982-12-02 Kabushiki Kaisha Komatsu Seisakusho, Tokyo FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES
CH668621A5 (en) * 1986-01-22 1989-01-13 Dereco Dieselmotoren Forschung FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE.
AT408133B (en) * 1990-06-08 2001-09-25 Avl Verbrennungskraft Messtech INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES
GB9422864D0 (en) * 1994-11-12 1995-01-04 Lucas Ind Plc Fuel system
US5517972A (en) * 1994-11-23 1996-05-21 Caterpillar Inc. Method and apparatus for rate shaping injection in a hydraulically-actuated electronically controlled fuel injector
US5732679A (en) * 1995-04-27 1998-03-31 Isuzu Motors Limited Accumulator-type fuel injection system
DE19780907C2 (en) * 1996-08-29 2003-02-06 Mitsubishi Motors Corp Fuel injection system

Also Published As

Publication number Publication date
ATE281597T1 (en) 2004-11-15
EP1125049A1 (en) 2001-08-22
JP2003507639A (en) 2003-02-25
WO2001014713A1 (en) 2001-03-01
DE19939421A1 (en) 2001-03-01
DE50008499D1 (en) 2004-12-09
US6491017B1 (en) 2002-12-10

Similar Documents

Publication Publication Date Title
EP1125049B1 (en) Combined stroke/pressure controlled fuel injection method and system for an internal combustion engine
EP1078160B1 (en) Fuel injection system
EP1125046B1 (en) Fuel injection system for an internal combustion engine with a pressure amplifier
EP1123462B1 (en) Fuel injection device
EP1520096B1 (en) Common rail injection system comprising a variable injector and booster device
EP1125058B1 (en) Fuel injection system for an internal combustion machine
DE10065103C1 (en) Pressure-controlled fuel injection device has pressure cavity connected by line containing valve directly to pressure storage cavity
DE19939420B4 (en) Fuel injection method and system for an internal combustion engine
EP1125054B1 (en) Fuel injection method and device
EP1125045B1 (en) Fuel injection system for an internal combustion engine
DE112006002672T5 (en) A fuel injection system having a flow control valve separate from a fuel injector
EP1370762B1 (en) Fuel injection device
EP1123463B1 (en) Fuel injection system for an internal combustion engine
EP1273797A2 (en) Fuel injection device
EP1121527B1 (en) Fuel injection device
DE19939425B4 (en) Fuel injection system for an internal combustion engine
WO2005015000A1 (en) Control valve with pressure compensation for a fuel injector comprising a pressure intensifier
EP1354133B1 (en) Fuel-injection device
EP1392965B1 (en) Pressure amplifier for a fuel injection device
EP1125044B1 (en) Fuel injection system for an internal combustion engine
DE10115396A1 (en) Fuel injection device for internal combustion engines

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

17P Request for examination filed

Effective date: 20010903

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20041103

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20041103

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20041103

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REF Corresponds to:

Ref document number: 50008499

Country of ref document: DE

Date of ref document: 20041209

Kind code of ref document: P

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: GERMAN

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20050203

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20050203

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20050203

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20050214

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 20050222

NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
REG Reference to a national code

Ref country code: IE

Ref legal event code: FD4D

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20050720

Year of fee payment: 6

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050802

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20050802

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050802

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050831

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050831

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050831

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050831

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

ET Fr: translation filed
26N No opposition filed

Effective date: 20050804

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060428

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20060428

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20060802

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060802

BERE Be: lapsed

Owner name: ROBERT *BOSCH G.M.B.H.

Effective date: 20050831

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050403

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20141024

Year of fee payment: 15

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 50008499

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20160301