EP0284601A2 - Dispositif d'injection pour moteurs diesel - Google Patents

Dispositif d'injection pour moteurs diesel Download PDF

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Publication number
EP0284601A2
EP0284601A2 EP88890075A EP88890075A EP0284601A2 EP 0284601 A2 EP0284601 A2 EP 0284601A2 EP 88890075 A EP88890075 A EP 88890075A EP 88890075 A EP88890075 A EP 88890075A EP 0284601 A2 EP0284601 A2 EP 0284601A2
Authority
EP
European Patent Office
Prior art keywords
piston
injection pump
fuel
injection device
injection
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.)
Granted
Application number
EP88890075A
Other languages
German (de)
English (en)
Other versions
EP0284601B1 (fr
EP0284601A3 (en
Inventor
Gottfried Dipl.-Ing. Haider
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.)
Automotive Diesel GmbH
Original Assignee
Voestalpine Metal Forming GmbH
Automotive Diesel 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 Voestalpine Metal Forming GmbH, Automotive Diesel GmbH filed Critical Voestalpine Metal Forming GmbH
Publication of EP0284601A2 publication Critical patent/EP0284601A2/fr
Publication of EP0284601A3 publication Critical patent/EP0284601A3/de
Application granted granted Critical
Publication of EP0284601B1 publication Critical patent/EP0284601B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection 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
    • F02M39/00—Arrangements of fuel-injection apparatus with respect to engines; Pump drives adapted to such arrangements
    • F02M39/005—Arrangements of fuel feed-pumps with respect to fuel injection apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/023—Injectors structurally combined with fuel-injection pumps characterised by the pump drive mechanical
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • F02M59/16—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps characterised by having multi-stage compression of fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • the invention relates to an injection device for diesel engines, in particular a pump nozzle, in which the fuel is conveyed by a backing pump into a suction chamber, which can be connected to the working chamber of the injection pump piston via at least one control bore in the pump piston sleeve, the delivery end of the injection pump piston being controlled by reducing the Fuel is determined through the control hole or control holes in the suction chamber.
  • a pump nozzle is to be understood as an injection device in which the injection pump is combined with the nozzle to form a structural unit that is assigned to a motor cylinder.
  • the relatively small dimensions of the control openings result in a high pressure loss, which leads to incomplete filling of the working space of the injection pump piston and also to cavitation.
  • the object of the invention is to improve the filling of the working space of the injection pump piston and the pressure peaks in the suction chamber when the fuel under high pressure is shut off at the end of delivery.
  • the invention consists essentially in the fact that at least one displacer piston, which is guided in a cylinder separate from the injection pump piston liner and is driven to reciprocating motion, is provided, the working chamber of which is in a constantly open connection with the suction chamber, the displacer piston being its working chamber before the start of delivery of the injection pump piston is reduced and enlarged at or after the end of delivery of the injection pump piston.
  • the displacer piston increases the fuel pressure in the suction chamber at the start of delivery above the backing pump pressure and thus the filling of the working area of the injection pump piston is improved despite the throttling in the control bore or in the control bores, and it becomes at or after the end of delivery of the injection pump piston when the high-pressure fuel enters the suction chamber, through the suction stroke of the displacer in the immediate area of the control bore increases the receiving volume of the suction chamber and thus reduces the pressure of the fuel, so that the pressure increase or pressure peak in the suction chamber which is caused by the deactivated fuel is reduced.
  • the displacement piston is hydraulically connected in parallel with the injection pump piston.
  • a fuel injection pump has become known, in which the injection pump piston with a second delivery piston, which is guided in a sleeve, consists of one piece. Through bores in the bushing controlled by control edges of this second delivery piston, the working space of this second delivery piston can be connected to a fuel inlet and to the suction chamber of the injection pump.
  • This second delivery piston delivers fuel into the suction space mainly after the start of delivery of the injection pump piston and increases the fuel pressure in the suction space by the pressure during the delivery of the injection pump piston to reduce the difference when switching off the fuel at the end of delivery in the suction chamber. It is not the pressure peak that is reduced here by reducing the pressure in the suction chamber during the control of the fuel, but only the pressure difference is reduced by increasing the pressure in the suction chamber before the control.
  • a non-return valve opening in the direction of the suction chamber is switched into the fuel supply line to the suction chamber, and according to a further preferred embodiment of the invention, an overpressure valve opening in the direction of the suction chamber is switched on in the fuel line.
  • connection advantageously opens out according to the invention Line from the working space of the displacement piston to the suction space between the fuel filter and the control bore.
  • the fuel filter offers a certain resistance to the spreading of the pressure difference generated by the displacement piston for supplying and removing fuel.
  • the arrangement of the mouth between the filter and the control bore therefore has the advantage that the pressure differences generated by the displacement piston are concentrated to a greater extent directly in the area of the control bore.
  • the arrangement is preferably such that the displacement piston approximately reaches its top dead center when the injection pump piston begins to deliver. In this way, the maximum pressure in the suction chamber occurs when the injection pump piston begins to deliver.
  • the arrangement is preferably made according to the invention so that the displacement piston has already passed its bottom dead center at the end of delivery of the injection pump piston. The pressure relief in the suction chamber then occurs when it is required to weaken the pressure peak occurring in the suction chamber at the end of the delivery due to the fuel which is controlled under high pressure.
  • top dead center is to be understood as the dead center of the displacement chamber facing the working space of the displacement piston and “bottom dead center” is the same as the dead center of the displacement chamber facing away from the working space of the displacement piston.
  • the displacement piston is expediently sealed in its guide, for example in an inserted bushing, by an O-ring. This ensures that fuel cannot get into the lubricating oil circuit.
  • the displacement piston can be guided in a sleeve inserted into the engine cylinder head.
  • the displacement piston is preferably in the Pump nozzle housing arranged. This has the advantage of simple installation and removal and simple guidance of the connection between the working space of the displacement piston and the suction space. Another advantage is that the pump nozzle according to the invention with the displacement piston can be used in the cylinder head instead of a known pump nozzle without redesigning the cylinder head.
  • the displacement piston is preferably arranged parallel to the axis of the injection pump piston liner and driven by a cam which is arranged on the same camshaft on which the cam actuating the injection pump piston is arranged.
  • the cams for driving the injection pump piston and for driving the displacement piston are expediently arranged on the engine camshaft.
  • the injection pump piston and the displacement piston can also be advantageously driven via a common rocker arm, the point of engagement of the rocker arm on the displacement piston being on a smaller radius of the rocker arm than the point of attack of the rocker arm on the injection pump piston.
  • the requirement is taken into account that the stroke of the displacement piston is smaller than the stroke of the injection pump piston.
  • Displacement pistons and injection pump pistons now carry out their stroke in the same direction, whereby the conditions are taken into account that the displacement piston reduces its working space before the injection piston begins to deliver, while the injection pump piston also reduces its working space during its forward stroke, and that the displacement piston after the end of the injection pump piston has ended its working space increases when the injection pump piston begins to enlarge its working space.
  • the plunger for the Drive of the displacement piston in the bearing block of the axis of the rocker arm must be guided.
  • FIG. 1 Shows an axial section through a pump nozzle inserted into the cylinder head with a displacement piston driven by a cam.
  • Fig. 2 shows a modified embodiment.
  • Fig. 3 shows schematically the assignment of the displacement piston to the injection pump piston.
  • 4 shows the geometric arrangement of the displacement piston cam relative to the injection pump piston cam.
  • 5 and 6 show the course of the fuel lines in the low-pressure circuit, FIG. 5 showing a section in line V of FIG. 6.
  • Fig. 7 shows another embodiment of the drive of the pump nozzle and the displacer.
  • FIG. 8 shows a path diagram of the displacement piston and the injection pump piston according to a cam arrangement according to FIG. 4.
  • the pump nozzle 1 is inserted into the cylinder head 2 of a diesel engine.
  • the injection pump piston 3 is driven by a cam 4, which is arranged on a camshaft 5, against the force of a spring 6.
  • 7 is the pump piston liner of the injection pump piston 3, which has control openings 8 which are closed by the piston at the start of delivery and are opened by a control groove of the piston 3 at the end of delivery.
  • 9 is the working space of the injection pump piston 3.
  • 10 is the injection nozzle, to which the fuel compressed in the working space 9 is supplied.
  • the fuel is supplied from a fuel supply bore 14 to the suction space 13 via an annular space delimited by two O-rings 11 and 12.
  • a filter 15 is inserted into the suction space 13.
  • a displacement piston 17 is guided to reciprocating movement and driven by a cam 18 against the force of a spring 19.
  • the cam 18 is arranged on the same camshaft 5 on which the cam 4, which acts on the roller tappet 20 of the injection pump piston 3, is also arranged.
  • the displacement piston 17 is guided in a bushing 21 inserted into the housing 16 and sealed by an O-ring 22, so that mixing of the fuel with the engine oil is avoided with certainty.
  • the working space of the displacer 17 is designated by 23.
  • the working space 23 of the displacer 17 is connected to the suction space 13 through bores 24 and 25 in the housing 16 of the pump nozzle.
  • the bore 25 opens into the suction space 13 at a point between the filter 15 and the control bore 8.
  • the embodiment according to FIG. 2 differs from the embodiment according to FIG. 1 in that the bushing 26 leading the displacement piston 17 is not inserted into the housing of the pump nozzle 27 but in the cylinder head 28.
  • the working space 29 of the displacement piston 17 is via a Bore 30 connected to the suction chamber 13.
  • the bore 30 now opens into the suction space 13 in front of the filter 15.
  • the function of the design from FIG. 2 is the same as the function of the design from FIG. 1.
  • FIG. 3 shows, on the basis of a section from FIG. 2 that is kept on a larger scale, the assignment of the displacement piston 17 to the injection pump piston 3 according to FIGS. 1 and 2.
  • the bottom dead center of the displacement piston 17 is denoted by a and the top dead center by b.
  • the bottom dead center of the injection pump piston 3 is denoted by c and the top dead center by d.
  • the displacer piston 17 displaces a fuel volume f during its stroke from its bottom dead center a to its top dead center b. This fuel volume f passes through the bore 30 into the suction chamber 13 and increases the fuel pressure there during the preliminary stroke e.
  • this fuel volume f is sucked back into the working space 29 of the displacer 17 and thus reduces the fuel pressure in the suction chamber 13, so that the pressure peaks occurring in the suction chamber at the end of delivery are weakened.
  • FIG. 4 shows the geometrical assignment of the cam 18 for driving the displacement piston 17 to the cam 4 for driving the injection pump piston 3.
  • the roller tappet cooperating with the cam 4 is indicated at 20 and the contact surface of the displacement piston is indicated at 17.
  • the representation according to FIG. 4 is rotated approximately 90 ° compared to the representation according to FIGS. 1 and 2.
  • the two cams 4 and 18 rotate in the direction of arrow 31. While the injection pump piston 3 travels the preliminary stroke e from the bottom dead center c to the start of delivery h, the displacement piston 17 is moved by the cam 18 from the bottom dead center a to the top dead center b, wherein the fuel volume f (Fig. 3) is pressed into the suction chamber 13.
  • the backing pump 32 feeds fuel from a tank 33 via a spring accumulator 34 into a feed bore 35 in the cylinder block 2 that is common to several pump nozzles 1.
  • the discharged fuel flows out of the cylinder block 2 via a collecting drain line 36, which is again common to all pump nozzles 1.
  • the fuel reaches the pump nozzles 1 via branch lines 37 to the individual pump nozzles 1, with non-return valves 38 opening in these branch lines 37 in the direction of the pump nozzles 1.
  • the deactivated fuel reaches the collective discharge line 36 via branch lines 39, overpressure valves 40, which open in the direction of the discharge line 36, being switched on in the branch lines 39.
  • FIG. 7 shows an embodiment in which the injection pump piston of the pump nozzle 41 is driven via a rocker arm 42 and a tappet 43.
  • 44 is the pivot axis of the rocker arm.
  • the rocker arm 42 is driven by a cam 45.
  • the displacer piston 46 is guided in a sleeve 47 which is inserted into the cylinder block 48.
  • the working chamber 49 of the displacement piston is connected to the suction chamber 51 through a bore 50 in the cylinder block 48.
  • the displacer piston 46 is driven against a spring 53 by a plunger 52.
  • the tappet 52 is guided in the bearing block 54 of the rocker arm axis 44.
  • the point of engagement 61 of the rocker arm 42 on the tappet 52 of the displacer 46 is at a smaller radial distance, etc. arranged approximately half the radial distance from the rocker arm axis 44 as the point of engagement 62 of the rocker arm 42 on the tappet 43 of the injection pump piston.
  • curve 63 shows the stroke profile of the injection pump piston and curve 64 shows the stroke profile of the displacement piston 17 according to FIGS. 1 and 2.
  • the bottom dead center of the injection pump piston 3 is c and the top dead center of the injection pump piston 3 denoted by d.
  • the bottom dead center of the displacement piston 17 is denoted by a and the top dead center by b.
  • the forward stroke of the injection pump piston 3 is designated by e.
  • the start of delivery of the injection pump piston is designated h and the delivery end of the injection pump piston is designated i. Both the start of delivery h and the end of delivery i of the injection pump piston (see curve 63) are variable depending on the load and start of injection.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Valve Device For Special Equipments (AREA)
  • High-Pressure Fuel Injection Pump Control (AREA)
EP88890075A 1987-03-26 1988-03-24 Dispositif d'injection pour moteurs diesel Expired - Lifetime EP0284601B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT746/87 1987-03-26
AT74687 1987-03-26

Publications (3)

Publication Number Publication Date
EP0284601A2 true EP0284601A2 (fr) 1988-09-28
EP0284601A3 EP0284601A3 (en) 1989-09-13
EP0284601B1 EP0284601B1 (fr) 1992-05-13

Family

ID=3498711

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88890075A Expired - Lifetime EP0284601B1 (fr) 1987-03-26 1988-03-24 Dispositif d'injection pour moteurs diesel

Country Status (3)

Country Link
EP (1) EP0284601B1 (fr)
AT (1) ATE76165T1 (fr)
DE (1) DE3870956D1 (fr)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB507940A (en) * 1938-02-05 1939-06-23 Austin Motor Co Ltd Improvements in or relating to internal combustion engines of the compression ignition type
US2592367A (en) * 1946-11-13 1952-04-08 American Bosch Corp Fuel injection system
US4083345A (en) * 1975-10-14 1978-04-11 Stanadyne, Inc. Fuel injection pump
DE3215047C2 (de) * 1982-04-22 1984-05-03 M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8900 Augsburg Brennstoffeinspritzsystem für eine Brennkraftmaschine
JPS61272461A (ja) * 1985-05-29 1986-12-02 Toyota Motor Corp 内燃機関の燃料噴射弁

Also Published As

Publication number Publication date
ATE76165T1 (de) 1992-05-15
EP0284601B1 (fr) 1992-05-13
DE3870956D1 (de) 1992-06-17
EP0284601A3 (en) 1989-09-13

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