EP0413430A1 - Kraftstoffdruckventil mit verstellbarem Entlastungsvolumen für eine Einspritzanlage - Google Patents

Kraftstoffdruckventil mit verstellbarem Entlastungsvolumen für eine Einspritzanlage Download PDF

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Publication number
EP0413430A1
EP0413430A1 EP90307401A EP90307401A EP0413430A1 EP 0413430 A1 EP0413430 A1 EP 0413430A1 EP 90307401 A EP90307401 A EP 90307401A EP 90307401 A EP90307401 A EP 90307401A EP 0413430 A1 EP0413430 A1 EP 0413430A1
Authority
EP
European Patent Office
Prior art keywords
fuel
retraction
valve
volume
collar
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.)
Withdrawn
Application number
EP90307401A
Other languages
English (en)
French (fr)
Inventor
Mark Alan Mitchell
David Peter Sczomak
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.)
Motors Liquidation Co
Original Assignee
Motors Liquidation Co
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 Motors Liquidation Co filed Critical Motors Liquidation Co
Publication of EP0413430A1 publication Critical patent/EP0413430A1/de
Withdrawn legal-status Critical Current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
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/14—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons
    • F02M41/1405—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined rotary distributor supporting pump pistons pistons being disposed radially with respect to rotation axis
    • 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
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/46—Valves
    • F02M59/462—Delivery valves

Definitions

  • This invention relates to fuel injection for internal combustion engines and more particularly to a fuel-delivery, variable-volume valve for a pumping system for directing high-pressure waves of fuel to a combustion chamber of an internal combustion engine as specified in the preamble of claim 1, for example as disclosed in SAE Paper No. 790899 (Hess et al).
  • fuel injector pumping systems for internal combustion engines have incorporated a fuel-delivery and retraction valve in the fuel flowing between a high-pressure pump and injector nozzles for combustion chambers of the engines.
  • This valve serves as a one-way check valve to seal the high-­pressure pumping chamber from the injector lines when fuel is not being delivered to the nozzle, and to control the residual line pressure with valve retraction and volume unloading. Without appropriate retraction and sealing, difficulties are encountered in shutting the fuel off at both low and high engine speeds.
  • venting constructions have been designed or proposed for such injector systems to vent injection lines after ignition has occurred in the associated combustion chamber to ensure that the lines have uniform residual pressure thereon for the injectors in preparation for subsequent delivery of pressure waves of fuel thereto. This helps to reduce late reflected pressure waves and to ensure that each line has the same balanced pressure after firing.
  • the engine may continue to operate for a time after the metering valve has closed-off fuel delivery to the high-pressure pump. This happens because a retraction collar has pulled too much fuel from the injection line at low engine speed causing a negative pressure differential to occur between the injection line and a transfer pump. Accordingly, instead of venting fuel under pressure in the injector line to the transfer pump, the fuel from the transfer pump is delivered to the injector line, bypassing the metering valve and delivery valve element. This may result in continued engine operation after shut-down thereof is desired.
  • a fuel-delivery, variable-volume valve assembly according to the present invention is characterised by the features specified in the characterising portion of claim 1.
  • the short-­circuiting of fuel from the transfer pump to the injection line which is open to vent is effectively eliminated by providing a variable-volume retraction valve collar on the delivery valve.
  • the retraction halve collar has leak paths provided by small flats extending across only a part of the retraction collar.
  • the flats produce only a small but definite retraction volume of fuel at low speed since there is fuel leakage around the flats as the valve retracts. With this small retraction volume, secondary fuel injection at low speed is eliminated and there are no pressure cavities formed in the line so that engine operation is rapidly terminated when the metering valve is closed.
  • the retraction volume of fuel progressively increases as engine speed increases from a predetermined low speed to a predetermined high speed since the effectiveness of the flats as leak paths decreases with speed.
  • the leakage paths provided by the small flats are ineffective since the time for leakage across the flats is minimal. Therefore, there is full retraction of fuel as the valve closes. Accordingly, with full fuel retraction, pressure waves of fuel reflecting from the injectors are reduced or dissipated so secondary fuel injection is minimized and there is good combustion maintenance for high-speed operation.
  • the length and depth of the leak path can be readily controlled by appropriate sizing of the depth and length of the flats to provide a mechanism for adjusting or tailoring retraction volume, particularly low-speed retraction volume.
  • a feature, object and advantage of the invention is to provide a new and improved variable-­volume retraction valve for a fuel-injector system which retracts varying volumes of fuel from injection lines for optimizing the fuel-handling performance and engine operation.
  • Another feature, object and advantage of this invention is to provide a new and improved variable-volume retraction valve that (1) will retract a definite but small volume of fuel from a fuel-injector line at low engine speeds so that secondary injections are eliminated and engine shut-down can be effectively and rapidly obtained; (2) will retract a definite and large volume of fuel from a fuel-injector line at speeds above a predetermined speed so that secondary injections are eliminated and good fuel combustion at high engine speeds is maintained and (3) will provide a seal between a pumping chamber of the pump and the line when the valve is closed so that further retraction of pumping plungers of the pump does not cause pressure cavities in the fuel in the line.
  • Another feature, object and advantage of this invention is to provide a new and improved retraction valve that retracts different volumes of fuel from a fuel-injection line as a function of engine speed including retraction volumes that progressively increase from a predetermined low-speed retraction volume to a predetermined high-speed retraction volume.
  • Another feature, object and advantage of this invention is to provide a variable volume retraction valve for an engine fuel-injector system with a fuel bleed across a portion of a fuel-delivery valve retraction collar, which bleed can be tailored in length and capacity for selective control of retraction volumes of fuel from injection lines to optimize the hydraulic performance of fuel-injection events.
  • FIG. 1 a hydraulic head assembly 10 of a distributor pump for pumping and distributing pressure waves of liquid fuel from a tank 12 to combustion chambers of an internal combustion engine 14.
  • the head assembly 10 is shown with discharge fitting 16 feeding combustion chamber 18 through high-pressure fuel injector line 20 and nozzle 22.
  • a second discharge fitting 24 of the head assembly feeds a second combustion chamber 26 diagrammatically shown in Fig. 2 through line 28 and nozzle 30.
  • the head assembly 10 includes a vane-type transfer pump 32 driven by the engine 14 that pumps fuel at low pressure from the fuel tank 12 through line 34 having water separator 36 and fuel filter 38 therein.
  • the output volume and pressure of pump 32 is controlled by a hydraulic pressure regulator 40 connected in parallel therewith.
  • the transfer pump has its output connected to a transfer line 42 that feeds into an annular charging passage 44 which connects to a metering valve 46 whose output is controlled by an engine-driven governor 48 mounted in distributor pump housing 50.
  • Quantities of fuel as metered by the valve 46 are fed by passage 54 to an annular charging passage 56 in a fixed body 57 of the head assembly that has arcuately-spaced and inwardly-extending ports 58 that are fixed for registry with inlet passages 60 of a fuel distributor rotor 62 that is rotatably mounted in the fixed body of the head assembly and driven by the engine so that rotor-mounted pumping plungers 64 of a cam-operated, high-pressure pump 66 can pump high-pressure waves of fuel from a pumping chamber 68 to a delivery and variable-volume retraction valve assembly 70 operatively mounted in a centralized bore 72 in the rotor 62.
  • the plungers 64 move radially outwards in their associated bores within the rotor 62 a distance proportional to the amount of fuel required for injection on the following stroke.
  • the metering valve 46 is highly restrictive and a correspondingly small volume of fluid is fed into the pumping chamber 68 so that the plungers move out a proportionally short distance.
  • the metering valve fully opens and the plungers are forced to their outermost position by proportionally increased volume of fuel from the metering valve.
  • the pumping plungers are moved inwards by a fixed cam ring 69 to pump pulses (pressure waves) of high-pressure fuel to the delivery and variable-volume retraction valve assembly 70 by way of an axial pump passage 76 of the rotor 62.
  • the valve assembly 70 has a valve element 78 mounted for linear shifting movement within the bore 72 at cycling frequencies that increase with engine speed.
  • the valve element 78 has a main cylindrical body 80 with a centralized axially-drilled bore 82, a blind end of which communicates with diametral cross-bores 84 that extend through the body 80 of the valve element 78 to terminate at an annular fuel-feed groove 86.
  • the entrance end of the blind bore 82 in the valve element communicates with a variable-volume connector chamber 90 that is primarily formed by the valve element 78 as it shifts in bore 72.
  • Chamber 90 being at the end of axial passage 76, communicates with the pumping chamber 68 of the high-pressure pump 66 and receives pressure waves of fuel therefrom when the inlet passages 60 are closed and the plungers 64 are moved inwards.
  • the outboard end of the valve element 78 has a cylindrical bore closure and retraction collar 96 integral with the main body 80, which collar extends outwards of the annular fuel-feed groove 86.
  • the bore closure and retraction collar 96 is lapped to slidingly and sealingly fit in the bore 72 when the valve element 78 is moved towards the seated position of Figure 4 in which inner end 98 of the valve element 78 contacts valve seat 100 formed by a wall at the inner end of bore 72 and chamber 90.
  • the valve element 78 is urged towards the seated position shown in Figure 4 by a helical return spring 104 located in a large-diameter bore forming a spring pocket 106.
  • This spring pocket 106 is co-axial with and hydraulically communicates with the smaller-diameter bore 72 during certain positions of movement of the valve element 78.
  • a fuel-delivery discharge passage 110 formed in the rotor 62 sequentially feeds, as the rotor 62 rotates, arcuately-spaced fuel-feed passages 112 and 114 in body 57 of the head assembly.
  • the feed passages 112 and 114 respectively connect into the two discharge fittings 16 and 24 that project from the head assembly.
  • the bore closure and retraction collar 96 is formed with a pair of diametrically-opposed retraction-volume-controlling flats 116 and 118 ground in the outer periphery thereof as best shown in Figures 4-7.
  • Each of these flats 116, 118 extends a predetermined distance from an inner face 120 of retraction collar to a terminal vertical wall 122 or 122′ located at a predetermined distance from the face 120 to provide fluid-leakage passages under certain fue-retraction collar positions and conditions.
  • the number of flats and their location are selected to suit operating requirements. In one preferred embodiment, a single flat has been utilized.
  • the return spring 104 mounted in the large-­diameter spring pocket 106 seats on an outer face 123 of the retraction collar and surrounds an end stop 124 that extends axially from the retraction collar 96 of the valve element 78.
  • the stop 124 is adapted to contact a projecting end of a valve lift stop 126 that is mounted in the large-diameter spring pocket 106, which valve lift stop also provides a seat for the outer end of return spring 104.
  • the valve lift stop 126 is trapped in position between the return spring 104 and a plug 128 threaded into the end of spring pocket 106.
  • Vane holders 130, 132 formed on the end of rotor 62 operatively support the vanes of the transfer pump 32 diagrammatically shown in Figure 1.
  • the rotor 62 has a longitudinally-extending vent groove 136 arcuately spaced from and adjacent to the fuel-­delivery passage 110 so that the injection line can be vented immediately after the injection event.
  • Figure 3 shows the rotor in the delivery position in which the delivery passage 110 registers with the fuel-feed passage 112 and a pressure wave of fuel is fed to injector line 20.
  • the continuously turning rotor turns, as shown by directional arrow A, to the Figure 1 position so that vent groove 136 registers with the passage 112 so that the injection line 20 will be vented to the transfer pump as diagramatically shown in Figure 1.
  • delivery passage 110 will align with feed passage 114 and fuel will be pumped to chamber 26 through line 28, as shown in Figure 2, and then the vent groove 136, arcuately spaced from delivery passage 110, will register with feed passage 114 to vent line 28 after the combustion event in chamber 26.
  • valve assembly 70 In fuel delivery operation for high engine speed, the valve assembly 70 is rapidly displaced from its valve seat 100 to the delivery position shown in Figure 3 by a wave of high pressure fuel.
  • This pressure wave is generated by the pumping plungers as they are moved inwards, and is transmitted into fuel-feed groove 86. Since groove 86 is opened to the spring pocket 106, the wave travels through the rotor discharge passage 110 into fuel feed passage 112 and into the fitting 16 for charging line 20 for the measured fuel injection of combustion chamber 18.
  • the valve element 78 When the valve element 78 has ended this delivery it moves toward its seat and, as illustrated in Figure 5, high-speed retraction begins.
  • the speed of the valve element is such that the flats 116, 118 have no bleeding effect because of quick closure and only minute amounts of fuel are squeezed through the small bleed openings provided by the flats. Accordingly, a full retraction volume of fuel illustrated by volume V1 in Figures 5 and 8 is produced so that secondary fuel injections are eliminated or reduced and good combustion at high speed can be maintained.
  • Figure 6 illustrates the valve element moved to the start of retraction position for low engine speed (from idle up to 2200 rpm). Because the valve element moves toward its seat at a relatively slow speed, the flats 116 and 118 are effective as fluid leak paths. Accordingly, the volume of fuel retracted by the retraction collar 96 as shown in Figures 6 is not as large as that retracted as shown in Figure 5, because of the leakage around the flats 116, 118 from chamber 90 into the spring pocket 106. As the valve moves to the seated Figure 4 position, the small volume V2 represents the small retraction volume of fuel at a low speed.
  • Figure 8 is a graph illustrating operation of this invention. From idle up to a predetermined engine speed N2, such as 2200 rpm, for example, a small volume V2 of fuel will be retracted from the injection lines. At a predetermined high speed N1, a large volume V1 of fuel will be retracted. As engine speed increases from N2 to N1, the retraction volume progressively increases as shown by curve R since the effectiveness of the fuel bleed path decreases with speed.
  • the pump can be shut-off at all speeds, even when rotor vent grooves are utilized since the retraction volume is small enough at low speeds to eliminate voids in the feed lines so the metering valve will not be circumvented.
  • the plungers themselves cannot retract fluid from the lines since the sealing surfaces of the retraction collar outward of flats 116, 118 seal bore 72 when the valve is in the seated position of Figure 4.
  • the retraction volume is still large enough to eliminate secondary injections and to provide good combustion.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
EP90307401A 1989-08-14 1990-07-06 Kraftstoffdruckventil mit verstellbarem Entlastungsvolumen für eine Einspritzanlage Withdrawn EP0413430A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US39318389A 1989-08-14 1989-08-14
US393183 1989-08-14

Publications (1)

Publication Number Publication Date
EP0413430A1 true EP0413430A1 (de) 1991-02-20

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EP90307401A Withdrawn EP0413430A1 (de) 1989-08-14 1990-07-06 Kraftstoffdruckventil mit verstellbarem Entlastungsvolumen für eine Einspritzanlage

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EP (1) EP0413430A1 (de)
JP (1) JPH0388959A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE112016005545B4 (de) 2015-12-03 2023-03-16 Denso Corporation Druckentlastungsventilvorrichtung und Hochdruckpumpe unter Verwendung derselben

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2026601A (en) * 1978-07-31 1980-02-06 Stanadyne Inc Fuel injection system delivery valve
GB2053372A (en) * 1979-07-06 1981-02-04 Lucas Industries Ltd Liquid fuel pumping apparatus

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2026601A (en) * 1978-07-31 1980-02-06 Stanadyne Inc Fuel injection system delivery valve
GB2053372A (en) * 1979-07-06 1981-02-04 Lucas Industries Ltd Liquid fuel pumping apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE112016005545B4 (de) 2015-12-03 2023-03-16 Denso Corporation Druckentlastungsventilvorrichtung und Hochdruckpumpe unter Verwendung derselben

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Publication number Publication date
JPH0388959A (ja) 1991-04-15

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