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
  • 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
  • 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
  • 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 relates to a fuel injection system for an internal combustion engine according to the preamble of patent claim 1.
• a fuel injection system has become known, for example, from EP 0 711 914 AI.
• the pressure at which fuel emerges from the nozzle chamber into the cylinder is referred to as the injection pressure, while a system pressure is understood to mean the pressure under which fuel is available or is stored in the injection system.
• a stroke-controlled Kraf tstof fine spray 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.
• a switch is made between different injection pressures and only one common valve is used to meter the fuel, this switching either central, i.e. before the fuel distribution to the individual cylinders, or locally, i.e. can be done individually for each cylinder.
• fuel is compressed to a first high system pressure of approximately 1200 bar with the aid of a high-pressure pump and stored in a first pressure accumulator. Furthermore, the fuel is under high pressure also conveyed into a second pressure accumulator, in which a second high system pressure of approx. 400 bar is maintained by regulating its fuel supply by means of a 2/2-way valve.
• a valve control unit either directs the lower or higher system pressure into the nozzle area of an injector. There, a spring-loaded valve body is lifted from its valve seat by the pressure, so that fuel can escape from the nozzle opening.
• a disadvantage of this known injection system is that all of the fuel first has to be compressed to the higher system pressure level in order to then relieve some of the fuel again to the lower system pressure level.
• the fuel injection system according to the invention which can be pressure-controlled or stroke-controlled, has the characterizing features of patent claim 1 and of patent claim 2 in order to increase the efficiency.
• the lower amount of fuel according to the invention at the higher system pressure leads not only to a higher efficiency but also to less stress on the pump load. components and, since the higher system pressure is not to be sealed against normal pressure, but only against the other high but lower system pressure, for better sealing and thus less leakage.
• Fig. La a stroke-controlled fuel injection system with a two-stage high-pressure pump for two pressure accumulators and with a combined fuel metering in the injector;
• FIG. 1b shows a stroke-controlled fuel injection system with a two-stage high-pressure pump for two pressure accumulators and with a combined fuel metering outside the injector;
• 2a shows a pressure-controlled fuel injection system with a two-stage high-pressure pump for two pressure accumulators and with a combined fuel metering in the injector
• 2b shows a pressure-controlled fuel injection system with a two-stage high-pressure pump for two pressure accumulators and with a combined fuel metering outside the injector
• FIG. 3 shows a pressure-controlled fuel injection system with a two-stage high-pressure pump for two pressure accumulators and with a combined central fuel metering;
• FIG. 4 shows a pressure-controlled fuel injection system with two pressure reservoirs each fed by a high-pressure pump and with a combined central fuel metering.
• the fuel is compressed to this lower system pressure of, for example, 300 bar and stored in the pressure accumulator 9.
• the pressure generation is regulated to the higher system pressure up to approximately 1800 bar and stored in the pressure accumulator 6.
• the injection takes place via a combined local fuel metering with the help of the injectors 8.
• the injector 8 has a piston-shaped valve member 11, which can be axially displaced in a guide bore, with a conical valve sealing surface 12 at one end, with which it has a valve seat surface on the injector housing of the injector 8 cooperates.
• Injection openings 13 are provided on the valve seat surface of the injector housing.
• a nozzle chamber 14 and a control chamber 15 are formed within the guide bore.
• the nozzle chamber 14 arises due to a reduction in the cross section of the valve member 11.
• the nozzle chamber 14 and the control chamber 15 are continuously connected to one of the two pressure accumulators 6, 9 via pressure lines 16 and 17 and a 3/2-way valve 18.
• the nozzle chamber 14 continues through an annular gap between the valve member 11 and the guide bore up to the valve seat surface of the injector housing.
• a pressure piece 22 also acts on the valve member 11, which delimits the control chamber 15 with its end face 23 facing away from the valve sealing surface 12.
• the spring chamber 19 is over a leakage line 21 for fuel return is connected to the storage tank 4.
• the control chamber 15 has an inlet with a first throttle 28 and an outlet to a pressure relief line 25 with a second throttle 24, which is connected by a 2/2-way valve.
• Valve 26 is controlled.
• the nozzle chamber 14 continues through an annular gap between the valve member 11 and the guide bore up to the valve seat surface of the injector housing.
• the pressure piece 22 is pressurized in the closing direction by the pressure in the control chamber 15.
• the 2/2 and 3/2 way valves 18, 26 are actuated by electromagnets for opening or closing or for switching the fuel lines 7 and 10.
• the electromagnets are controlled by a control unit, which can monitor and process various operating parameters (engine speed, ...) of the internal combustion engine to be supplied.
• the respective pressure in the two pressure accumulators 6, 9 can be detected by means of pressure sensors and kept constant by means of a control device.
• the pressure in the control chamber 15 can be reduced, so that the pressure in the nozzle chamber 14 acting in the opening direction exceeds the pressure acting on the valve member 11 in the closing direction ,
• the valve sealing surface 12 lifts off the valve seat surface and fuel is injected.
• the relief process of the control chamber 15 and thus the stroke control of the valve member 11 can be influenced by the dimensioning of the throttle 24 and a further throttle 28.
• the end of the injection process is initiated by actuating (closing) the 2/2-way valve 26, which controls the control chamber 15 connects again to the pressure line 17, so that a pressure builds up again in the control chamber 15 which can move the valve member 11 in the closing direction.
• the 3/2-way valve 18 can also be replaced by a 2/2-way valve and a check valve.
• valves actuated by means of electromagnets it is also possible to use piezo actuating elements which have the necessary temperature compensation and a possible force or displacement translation.
• a combined pressure accumulator (combined rail) can also be provided.
• An outer pressure storage space with the lower system pressure encloses an inner pressure storage space with the higher system pressure. In this way, low pressure gradients occur, which expose a housing of the pressure storage spaces to lower material loads and, for example, allow the formation of an even higher pressure in the high-pressure storage space.
• the 3/2-way valve 18 is not in the injector, but outside the injector 8 a, e.g. arranged in the area of the pressure accumulators 6, 9.
• a smaller size of the injector 8a and an increased injection pressure can be achieved by utilizing wave reflections in the now longer pressure lines 16.
• fuel is supplied from a fuel tank 31 to the injectors 32 by four cylinders and from there via injection openings 33 into the combustion chamber 34 of the respective one Promoted cylinders.
• a quantity-controlled two-stage high-pressure pump 35 is used to generate two different, high system pressures.
• the fuel In the first, lower pump stage, the fuel is compressed to a first high system pressure of approximately 300 bar, which is stored in a first pressure accumulator 36 (first rail).
• first pressure accumulator 36 first rail
• second, higher pumping stage the fuel is compressed to a second higher system pressure of approximately 300 bar to approximately 1800 bar and then stored in a second pressure accumulator 37 (second rail).
• a control circuit with a pressure sensor is provided for each of the two pressure accumulators 36, 37.
• the lower system pressure level can be used for the pre-injection and, if necessary, for the post-injection, as well as for the main injection if a low injection pressure is required.
• a 2/2-way valve 38 is provided for each cylinder or injector 32 as a switching element for the high-pressure side, the output of which from the low-pressure side through a check valve 39 (or through a 3/2 way valve) is disconnected.
• a 3/2-way valve 40 the prevailing pressure is then conducted via a line 41 into the nozzle chamber 42 of the injector 2, which is designed in a pressure-controlled manner. That is, its nozzle needle 43, which seals the injection openings 33, is opened by the pressure prevailing in the nozzle chamber 32 against the action of a closing force.
• an injection with a lower injection pressure takes place by energizing the 3/2 -way valve 10.
• a high-pressure injection is then carried out Injection pressure switched, the check valve 39 prevents an unwanted return from the high pressure side to the low pressure side.
• the 3/2-way valve 40 is switched to leakage 44. This relieves on the one hand the line 41 and on the other hand the nozzle space 42, so that the spring-loaded nozzle needle 43 closes the injection openings 33 again.
• valve arrangement formed from the two valves 38, 40 and the check valve 39 is located in the injector 32 in the exemplary embodiment in FIG. 2a, in the injection system shown in FIG. 2b this valve arrangement is located outside the injector 32a, e.g. arranged in the area of the pressure accumulator 36, 37. In this way, a smaller size of the injector 32a and by using
• the second 3/2-way valve 46 is switched to leakage 49 and thus the respective line 48 is provided between the distributor device 47 and the injector 32. Hene valve assembly from check valve 50 and throttle 51 relieved.
• the two-stage high-pressure pump 35 shown in FIG. 2 is replaced by a high-pressure pump 35 a that only feeds the first pressure accumulator 37 and a high-pressure pump 35 b that only feeds the second pressure accumulator 36.
• Both magnetic actuators and piezo actuators which enable faster valve switching, can be used for the valves.
• the 3/2-way valves can also be replaced by a combination of two 2/2-way valves.
• an arrangement of a 2/2 way valve and a non-return valve is also possible with a given relief of the injector.

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• 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)

Applications Claiming Priority (3)

Publications (2)

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ID=7918959

Family Applications (1)

Country Status (6)

Families Citing this family (16)

Family Cites Families (9)

• 1999
  • 1999-08-20 DE DE19939424A patent/DE19939424A1/de not_active Ceased
• 2000
  • 2000-08-02 AT AT00958195T patent/ATE283424T1/de not_active IP Right Cessation
  • 2000-08-02 WO PCT/DE2000/002550 patent/WO2001014710A1/fr active IP Right Grant
  • 2000-08-02 JP JP2001518559A patent/JP2003507636A/ja active Pending
  • 2000-08-02 US US09/807,879 patent/US6499465B1/en not_active Expired - Fee Related
  • 2000-08-02 DE DE50008747T patent/DE50008747D1/de not_active Expired - Lifetime
  • 2000-08-02 EP EP00958195A patent/EP1125045B1/fr not_active Expired - Lifetime

Non-Patent Citations (1)

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