WO2000017516A1 - Systeme d'injection de carburant - Google Patents

Systeme d'injection de carburant Download PDF

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Publication number
WO2000017516A1
WO2000017516A1 PCT/DE1999/002791 DE9902791W WO0017516A1 WO 2000017516 A1 WO2000017516 A1 WO 2000017516A1 DE 9902791 W DE9902791 W DE 9902791W WO 0017516 A1 WO0017516 A1 WO 0017516A1
Authority
WO
WIPO (PCT)
Prior art keywords
pressure
pump
injection system
fuel
feed
Prior art date
Application number
PCT/DE1999/002791
Other languages
German (de)
English (en)
Inventor
Egon Eisenbacher
Original Assignee
Siemens Aktiengesellschaft
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 Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Priority to EP99953704A priority Critical patent/EP1115975B1/fr
Priority to DE59907743T priority patent/DE59907743D1/de
Publication of WO2000017516A1 publication Critical patent/WO2000017516A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/02—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
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B23/00—Pumping installations or systems
    • F04B23/04—Combinations of two or more pumps
    • F04B23/08—Combinations of two or more pumps the pumps being of different types
    • F04B23/10—Combinations of two or more pumps the pumps being of different types at least one pump being of the reciprocating positive-displacement type
    • F04B23/103—Combinations of two or more pumps the pumps being of different types at least one pump being of the reciprocating positive-displacement type being a radial piston pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/22—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by means of valves
    • F04B49/24—Bypassing
    • F04B49/246—Bypassing by keeping open the outlet valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2205/00—Fluid parameters
    • F04B2205/15—By-passing over the pump

Definitions

  • the invention relates to a fuel injection system for an internal combustion engine, in particular a diesel engine according to the preamble of patent claim 1.
  • FIG. 1 The basic concept of such a common rail diesel engine is shown in FIG. 1, to which reference is already made.
  • the fuel is drawn from a tank 4 via a prefeed pump 2 and is pumped into a high-pressure pump.
  • Pen device 6 brought to the required fuel pressure with a high pressure pump, not shown, and the associated switching elements.
  • the pressurized fuel is fed to the prescribed common high-pressure line, the common rail 8.
  • the common rail injection system enables cylinder-specific control, so that, for example, combustion processes of different strengths are avoided in the individual cylinders and the smoothness of the diesel engine can thus be considerably improved compared to conventional systems. Since the high injection pressure is already available at low engine speeds, an optimal mixture preparation is achieved in the cylinders, which leads to an improvement in fuel consumption and a reduction in exhaust gas emissions.
  • a rapid pressurization of the fuel delivered to the common rail to a minimum level which can be, for example, 150 bar, is required in order to atomize the fuel in the required form when the engine is started.
  • the high-pressure pump device 6 Since the high-pressure pump device 6 is usually coupled to the internal combustion engine, immediately after the engine has started it does not deliver enough pressure to bring the fuel to the aforementioned minimum level of 150 bar. A larger dimensioning of the high-pressure pump device would increase the manufacturing costs of the diesel engine and also the energy consumption, since this pump would be too large in normal operation, i.e. with a warm engine.
  • a Commq.n-Rail injection system is presented in DE 3315927A1, in which the high-pressure pump device 6 is bypassed when the engine is started by means of a bypass circuit, so that the common rail 8 is fed solely by the pre-feed pump 2.
  • the pre-feed pump 2 is driven by an auxiliary motor, so that the power of the pre-feed pump 2 is sufficient to bring the fuel to the required pressure level.
  • US Pat. No. 5,626,121A shows a common rail injection system in which, similar to the exemplary embodiment described above, the high-pressure pump device 6 is bypassed via a bypass line when the engine is started and the common rail 8 by the pre-feed pump 2 to the required level Pressure level is brought.
  • the object of the invention is to create a fuel injection system in which the fuel supply is ensured in the required manner with minimal expenditure on device technology, even when the engine is started.
  • a fuel injection system with the features of claim 1.
  • the measure of providing a pressure relief valve device upstream of a high-pressure pump by means of which the feed pressure of the high-pressure pump is raised to the pressure level required when the engine is started, depending on the pressure in the common rail, the fuel can be atomized in the required manner from the start become.
  • the fuel pressurized via the pre-feed pump then propagates into the common rail via the suction and pressure check valves of the high-pressure pump device. Since the high-pressure pump is flowed through when starting, no separate switching elements have to be provided in order to bypass the high-pressure pump or to prevent backflow from the common rail.
  • the fuel is compressed via the pre-feed pump and the high-pressure pump, so that the feed pressure can be reduced to the predetermined low pressure level via the pressure limiting valve device, so that the pre-feed pump no longer has to be operated at the increased output.
  • a particularly simple fuel injection system can be obtained if the pressure relief valve arrangement has a pressure shutoff or pressure relief valve.
  • control spring of the pressure cut-off or pressure relief valve is designed such that the opening pressure must exceed approximately 150 bar.
  • a suction throttle valve is connected upstream between the suction side of the high-pressure pump in order to increase operational safety, via which the feed pressure is possible through a suction throttle control of the high pressure pump.
  • the feed pressure of the high-pressure pump can also be varied in that the pressure relief valve arrangement can be controlled electrically or electro-hydraulically as a function of the operating state of the internal combustion engine, so that the feed pressure can be varied accordingly.
  • the prefeed pump is designed as an electrically operated positive displacement pump and the high pressure pump as a radial piston pump driven by the internal combustion engine.
  • the pressure relief valve arrangement can be combined into a single valve.
  • FIG. 1 shows a schematic representation of a diesel engine with a common rail injection system
  • FIG 2 is a circuit diagram of a fuel injection system according to the invention for the internal combustion engine shown in Figure 1.
  • the fuel is conveyed from a tank 4 via a prefeed pump 2, compressed to a feed pressure and conveyed via a feed line 14 to the inlet connection of the high-pressure pump device 6.
  • this has a high pressure pump 16 and an upstream suction throttle valve 18, which is designed as a 2-way valve in the embodiment shown and can be actuated electrically or electrohydraulically.
  • the control takes place via the control of the internal combustion engine, not shown.
  • the suction throttle valve 18 In its spring-biased basic position, the suction throttle valve 18 is biased into a flow position. By actuation via the motor control, the suction throttle valve 18 can be brought into its blocking position, so that the supply to the high-pressure pump 16 is interrupted. This can take place, for example, in the event of a fault in the injection system, so that the fuel supply to the cylinders is interrupted.
  • the suction throttle valve 18 should be designed to be adjustable, so that suction throttle control of the high-pressure pump 16 is possible.
  • the high-pressure pump 16 is usually driven via the crankshaft of the internal combustion engine, while the prefeed pump 2 is a large-sized fuel pump which is also driven by the internal combustion engine. Alternatively, this could also have its own, for example electric drive.
  • high-pressure pumps in radial piston construction are usually used, as are described, for example, in DE 42 16 877 C2. Since the construction of these high-pressure pumps 16 is already known from the prior art, a detailed description can be dispensed with.
  • the pressurized fuel is over a
  • High-pressure line 20 is conveyed into the common rail 8, and injected from the latter via the injection nozzles 10 into the cylinder spaces.
  • a return line 22 branches off from the feed line 14, via which a connection to the tank 4 can be established.
  • a pressure modulation or feed pressure relief valve 24 is connected, which is designed as a pressure relief valve in the embodiment shown. In its spring-preloaded basic position, this blocks the connection between the return line 22 and a tank line 26.
  • the pressure at the inlet of the feed pressure relief valve 24 is fed via a control line 30 to the end face of the valve member of the feed pressure relief valve 24 acting against the control spring 28.
  • the feed pressure limiting valve 24 is brought into its flow position, so that a connection to the tank 4 is opened via the tank line 26.
  • the feed pressure limiting valve 24 shown in FIG. 2 can also be designed as an electrically operated valve, the control of which is likewise carried out via the motor control.
  • the feed pressure to the high-pressure pump device 6 can then be modulated by suitable control, so that the pressure in the common rail 8 can be adjusted.
  • circuit according to the invention differs only slightly from conventional common rail injection systems.
  • the feed pressure limiting valve 24 is preceded by a pressure cut-off or a pressure limiting valve 32, which is biased into its closed position by a compression spring 34.
  • the compression spring 34 has a significantly higher spring rate than the control spring 28 and is selected in the exemplary embodiment shown so that a control pressure in the range of 150 bar must be present in order to overcome the force of the compression spring 34. In contrast, a pressure of less than 10 bar in the control line 30 is sufficient to override the force of the control spring 28.
  • the valve member of the pressure shut-off valve 32 is acted upon in the opening direction by the pressure in a high-pressure control line 36, via which the pressure in the common rail 8 is reported to the pressure shut-off valve 32.
  • the electrically operated pre-feed pump 2 starts immediately, while the high-pressure pump 2 driven by the crankshaft of the internal combustion engine is not yet able to deliver the required starting pressure of 150 bar, for example, due to the low engine speed.
  • the pressure shut-off valve 32 is in its blocking position due to the force of the compression spring 34, so that the return line 22 to the tank 4 is shut off.
  • the pre-feed pump 2 delivers at maximum power and is designed so that it can deliver the required starting pressure of about 150 bar.
  • the suction throttle valve 18 is in a flow position, so that the fuel pressurized via the pre-feed pump 2 via the suction valves (not shown). and pressure check valves of the high pressure pump 16 is conveyed into the high pressure line 20.
  • the high-pressure pump 16 makes a negligible contribution to the compression of the fuel 20. That is, the pressure in the common rail 8 is brought essentially to the minimum level by the action of the prefeed pump 2, so that the atomization is acceptable Fuel is required.
  • the pressure in the common rail 8 is reported via the high-pressure control line 36 to the control side of the pressure cut-off valve 32.
  • the preset pressure level for example 150 bar
  • the pressure cut-off valve 32 is brought into its flow position so that the connection of the return line 22 to the feed pressure limiting valve 24 is opened.
  • the feed pressure limiting valve 24 is brought into its flow position, so that the connection to the tank T is opened and the pressure in the return line 22 is reduced to the preset feed pressure of less than 10 bar.
  • the starting process of the internal combustion engine has now been completed, so that the high-pressure pump runs at the required speed in order to bring the fuel from the preset supply pressure ( ⁇ 10 bar) to the pressure level required in the common rail 8. This means that after the starting process is completed, the pre-feed pump 2 is relieved of pressure, so that it only has to bring the normally required feed pressure of up to 10 bar.
  • the circuit according to the invention has a much simpler structure than the injection systems described at the outset, since in principle only the pre-feed pump 2 and the suction throttle valve 18 are to be dimensioned with regard to the pressure level of approximately 150 bar required during the starting process. As an additional component, only the pressure shut-off valve 32 has to be provided, which is connected upstream of the feed pressure limiting valve 24. A large-sized pre-feed pump 2 can thus ensure a quick starting behavior of the internal combustion engine with minimal energy consumption and low expenditure on device technology.
  • valve and control devices can also be provided in order to bring the feed pressure in the feed line 14 to the required high pressure level during the starting process.
  • a pressure limiting valve can also be used, for example.
  • the main advantage of the invention over the conventional solutions is that no complex circuit for bypassing the high-pressure displacer has to be provided during the starting process, so that only existing line and valve means have to be added.
  • a fuel injection system for an internal combustion engine with a prefeed pump and a high-pressure pump, from which pressurized fuel can be conveyed into a common rail.
  • the feed pressure of the high-pressure pump is brought to a high pressure level, so that the pressure required for optimal atomization builds up very quickly in the common rail.

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

Abstract

L'invention concerne un système d'injection de carburant destiné à un moteur à combustion interne, qui comporte une pompe de pré-alimentation (2) et une pompe haute pression (16) à partir de laquelle du carburant sous pression peut être amené à une rampe commune d'alimentation (18). Au moment du démarrage du moteur à combustion interne, la pression d'alimentation de la pompe haute pression (16) est amenée à un niveau élevé de telle sorte que, dans la rampe commune d'alimentation (18), la pression nécessaire à une pulvérisation optimale s'établit très vite.
PCT/DE1999/002791 1998-09-24 1999-09-02 Systeme d'injection de carburant WO2000017516A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP99953704A EP1115975B1 (fr) 1998-09-24 1999-09-02 Systeme d'injection de carburant
DE59907743T DE59907743D1 (de) 1998-09-24 1999-09-02 Kraftstoffeinspritzsystem

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19843940.7 1998-09-24
DE19843940A DE19843940A1 (de) 1998-09-24 1998-09-24 Kraftstoffeinspritzsystem

Publications (1)

Publication Number Publication Date
WO2000017516A1 true WO2000017516A1 (fr) 2000-03-30

Family

ID=7882178

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1999/002791 WO2000017516A1 (fr) 1998-09-24 1999-09-02 Systeme d'injection de carburant

Country Status (3)

Country Link
EP (1) EP1115975B1 (fr)
DE (2) DE19843940A1 (fr)
WO (1) WO2000017516A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19912666A1 (de) 1999-03-20 2000-09-21 Bosch Gmbh Robert Brennstoffeinspritzentil
DE102004046095B4 (de) * 2004-09-23 2018-02-15 Robert Bosch Gmbh Brennstoffeinspritzventil
DE102005003592A1 (de) * 2005-01-26 2006-08-03 Daimlerchrysler Ag Kraftstoffversorgungseinrichtung
DE102007016764A1 (de) 2007-04-07 2008-10-09 Audi Ag Verfahren zum Betreiben eines Kraftstoffeinspritzsystems im Startvorgang und Kraftstoffeinspritzsystem hierzu

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19539885A1 (de) * 1995-05-26 1996-11-28 Bosch Gmbh Robert Kraftstoffversorgungsanlage und Verfahren zum Betreiben einer Brennkraftmaschine
DE19612412A1 (de) * 1996-03-28 1997-10-02 Rexroth Mannesmann Gmbh Regelung für ein Druckfluid-Versorgungssystem, insbesondere für den Hochdruck in einem Kraftstoff-Einspritzsystem
DE19618707A1 (de) * 1996-05-09 1997-11-20 Siemens Ag Verfahren und Vorrichtung zur Regelung eines Kraftstoffvolumenstromes

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19539885A1 (de) * 1995-05-26 1996-11-28 Bosch Gmbh Robert Kraftstoffversorgungsanlage und Verfahren zum Betreiben einer Brennkraftmaschine
DE19612412A1 (de) * 1996-03-28 1997-10-02 Rexroth Mannesmann Gmbh Regelung für ein Druckfluid-Versorgungssystem, insbesondere für den Hochdruck in einem Kraftstoff-Einspritzsystem
DE19618707A1 (de) * 1996-05-09 1997-11-20 Siemens Ag Verfahren und Vorrichtung zur Regelung eines Kraftstoffvolumenstromes

Also Published As

Publication number Publication date
EP1115975A1 (fr) 2001-07-18
DE59907743D1 (de) 2003-12-18
EP1115975B1 (fr) 2003-11-12
DE19843940A1 (de) 2000-03-30

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