EP0357247A1 - Brennstoffeinspritzsystem - Google Patents

Brennstoffeinspritzsystem Download PDF

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Publication number
EP0357247A1
EP0357247A1 EP89307957A EP89307957A EP0357247A1 EP 0357247 A1 EP0357247 A1 EP 0357247A1 EP 89307957 A EP89307957 A EP 89307957A EP 89307957 A EP89307957 A EP 89307957A EP 0357247 A1 EP0357247 A1 EP 0357247A1
Authority
EP
European Patent Office
Prior art keywords
nozzle
injector
valve
flow
fuel
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Withdrawn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
EP89307957A
Other languages
English (en)
French (fr)
Inventor
Paul Buckley
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.)
ZF International UK Ltd
Original Assignee
Lucas Industries Ltd
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 Lucas Industries Ltd filed Critical Lucas Industries Ltd
Publication of EP0357247A1 publication Critical patent/EP0357247A1/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Withdrawn legal-status Critical Current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
    • 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
    • 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
    • F02M45/08—Injectors peculiar thereto
    • 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
    • F02M45/12—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship providing a continuous cyclic delivery with variable pressure
    • 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
    • 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
    • F02M2200/28—Details of throttles in 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
    • 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
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0054—Check valves

Definitions

  • This invention relates to fuel injection systems and to injectors and flow restrictors for use in fuel injection systems.
  • diesel knock can be reduced by controlling the flow through the injector so that the rate of injection is reduced at the beginning of the delivery of the fuel. This means that the amount of fuel in the combustion chamber when combustion begins is lower thus reducing diesel knock.
  • Conventional inwardly opening injectors comprise a nozzle body defining a bore at one end of which is provided a seating surface. Downstream of the seating surface the nozzle body defines one or more spray orifices.
  • a nozzle valve is slidably mounted within the nozzle body and has a seating surface and is urged into sealing engagement with the seating surface of the nozzle body by a valve spring. Inward displacement of the nozzle valve allows fuel to pass to the or each spray orifice. In operation, the nozzle valve prevents flow of fuel through the injector until the pressure supplied to the injector is sufficiently high to lift the nozzle valve. In such injectors, it is found that the degree of restriction presented to the fuel flow as the nozzle valve is displaced inwardly is highly sensitive to the lift of the valve and the range of lift over which the fuel flow is restricted is small.
  • a fuel injection system including an injection pump, an injector and flow restrictor means for controlling the flow of fuel injected by said injector, said flow restrictor means defining a first flow path having a relatively high degree of restriction and an alternative second flow path having a relatively low degree of restriction, said flow restrictor means including valve means operable to close said second flow path when the pressure upstream thereof is below a preset pressure.
  • a restrictor for use in fuel injection systems comprising a body having a bore therein, one end of the bore being a fluid entry opening and the other end of the bore being a fluid exit opening, there being a valve member located in said bore between said openings, the valve member having a central aperture of small cross-sectional area, a land surrounding said area, and flutes surrounding said land, the valve member being biassed in such a direction that it normally engages the land and is lifted therefrom when the applied fluid pressure exceeds a preset value so permitting fluid flow past the flutes.
  • said flow restrictor means includes a restrictor body defining therein a restrictor valve chamber having an inlet, an outlet and a valve seat, and a restrictor valve element associated with said restrictor valve seat for opening or closing said second flow path and having a passage defining said first flow path.
  • said restrictor valve element is slidably mounted in said restrictor valve chamber and said second flow path passes adjacent to external flutes provided on said restrictor valve element.
  • said restrictor body is connected to the fuel inlet of said injector.
  • said restrictor valve chamber is formed internally of the injector.
  • a typical injector includes at least a main body portion having an inlet and an outlet for fuel, and a nozzle portion.
  • the restrictor valve chamber is defined within said main body portion.
  • the restrictor valve chamber is formed in a plate disposed between said main body portion and said nozzle portion.
  • the fuel injection system comprises an injector pump 10 which supplies metered charges of fuel at timed intervals to an injector generally designated 12 via a flow restrictor generally designated 14.
  • the injector 12 is a conventional, inwardly opening, injector and includes a nozzle body 16 having an internal bore 18, an annular fuel gallery or reservoir 20, a valve seating 22 and a sac 24 defining a plurality of spray orifices (not shown).
  • a nozzle valve 26 is slidably mounted within the bore 18 and includes a pressure receiving surface 28 and a seating surface 30.
  • the nozzle valve is preloaded by a compression spring 31 to a position in which the seating surface 30 sealingly engages the valve seating 22.
  • the preload is set to the initial opening pressure required by the diesel engine, as in the case of a conventional injector.
  • the flow restrictor 14 defines a first flow path 32 having therein a precisely formed restriction 33, and a second flow path 34 which is unrestricted save for a restrictor valve assembly 36 which prevents flow along the second path at low pressures.
  • the restrictor valve assembly 36 comprises a restrictor valve housing 38 and a restrictor valve element 40 spring-biased by a compression spring 41 to close the inlet to the valve housing 38.
  • Each of the first and second flow paths 32, 34 are connected to the injector 12.
  • the restriction 33 and the opening pressure of the restrictor valve assembly 36 are selected so that during engine idle, the fuel pressure in the second flow path 36 is below the changeover pressure of the restrictor valve assembly 36 and the fuel passes at a relatively low rate along the first path 32 alone to provide good low speed combustion characteristics.
  • the fuel pressure in the second flow path 34 will be above the changeover pressure of the restrictor valve assembly 36 so that fuel will pass along both the first and the second flow paths 32, 34. In this condition, the fuel flow is controlled by the spray orifices of the nozzle in the usual fashion.
  • the injector is mainly of conventional design including a main body 200 defining an inlet 202 for receiving fuel and a leak-off connection 204 for passing fluid which leaks around the nozzle valve back to the fuel tank. Fuel passing through the inlet 202 passes via internal passages 206 to an annular fuel gallery (not shown) formed in the nozzle body 208.
  • the nozzle body 208 and the nozzle valve 210 (only the upper stem of which is seen in Figure 2) are of conventional design, similar to that shown in Figure 1, and are not therefore described or shown in detail here.
  • the upper end of the stem 210 engages the lower end of a spring support 212 which supports the lower end of a compression spring 214.
  • the compression spring is located within a bore in the main body 200 of the injector and its upper end engages a shim 216. Between the main body 200 and the nozzle body 208 is a disc plate 218. The nozzle body 208 is secured to the main body 200 by a nozzle cap nut 221.
  • the injector as described so far is of generally conventional design.
  • the injector however is fitted with a flow restrictor 220 which is connected to the inlet 202 of the injector.
  • the flow restrictor 220 comprises a restrictor body 222 having an inlet 224 and an outlet 226. Between the inlet 224 and the outlet 226 is defined a generally cylindrical restrictor valve chamber 228 which slidably receives a restrictor valve element 230.
  • the restrictor valve element 230 has a bore 232 of restricted diameter and includes a generally frusto-conical seating surface 234 for engaging an associated seating surface 236 at the inlet end of the restrictor valve chamber 228.
  • the restrictor valve element also includes a plurality of external flutes 238 which lie radially outside the seal defined between the frusto-conical seating surface 234 and the associated seating surface 236 and which together define a passage having an aggregate sectional area which is much greater than that of the bore 232.
  • a compression spring 240 is located between a sleeve 242 and the restrictor valve element 230 and urges the restrictor valve element into sealing engagement with the sealing surface 236 at the inlet end of the restrictor valve chamber 228.
  • the bore 232 defines a first flow path having a relatively high degree of restriction whilst the flutes 238 together define a second flow path having a relatively low degree of restriction.
  • fuel delivered at low pressures passes only through the bore 232 defining the first flow path and is thus throttled so that the rate of injection is lowered.
  • the pressure drop generated across the bore 232 causes the restrictor valve element 230 to lift off the seating surface 236 to allow flow along the second flow path as well as the first flow path so the rate of injection is increased.
  • the restrictor valve element 230 has a high differential area so that it stays open after operation and also so that the pressure drop across the restrictor valve element when it is open is minimised.
  • the restrictor valve element 230 is returned to its closed position at the end of injection by the action of the spring 240.
  • An advantage of using the flow restrictor 220 as shown in Figure 2 is that, during closure of the injector nozzle, the reverse flow out of the nozzle is limited by the restricted diameter bore 232 and so the nozzle will continue to pump fuel because of the volume displaced from the nozzle valve. This will assist in preventing blow back and ensuring a sharp end of injection to give further reductions of smoke.
  • a further advantage of the arrangement of Figure 2 is that it does not require modification of the nozzle of the injector.
  • the flow restrictor 220 can therefore be retro-fitted to existing injectors without modifying the geometry of the remainder of the injector.
  • Figures 3 and 4 show alternative locations for the flow restrictor.
  • Figure 3 shows the upper end of an injector of the general type shown in Figure 2 except that the positions of the fuel inlet 202 and the leak-off connection are transposed so that the fuel inlet is at the top of the injector.
  • the flow restrictor is of similar design to that of Figure 2 except that there is no separate restrictor body. Instead, the restrictor valve chamber 228 and its inlet 224 and outlet 226 are formed in the main body 200 of the injector.
  • Other parts of the flow restrictor are similar to those of Figure 2 and are given the same reference numerals and will not be described in detail again.
  • Figure 4 shows the lower end part of an injector in which the flow restrictor is located in the plate 218 of a conventional injector, in the passage 208 connecting the fuel inlet (not shown) of the injector with the annular fuel gallery (not shown) in the nozzle body 208.
  • the restrictor valve chamber 228 and its inlet and outlet are formed in the plate 218.
  • Other parts of the restrictor are similar to those of Figures 2 and 3 and will not be described in detail.
  • the injector nozzles shown in the drawings are of the inwardly opening type and incorporate a sac. It will however be understood that the principles disclosed herein may also be used on other types of inwardly opening nozzles without a sac, such as v.c.o. (valve closed orifice) nozzles, pintle nozzles, as well as on outwardly opening nozzles. It will also be understood that the compression spring 31, 214 which urges the nozzle valve to its closed position may be replaced by other resilient means which urge the nozzle valve to its closed position.

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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)
EP89307957A 1988-09-01 1989-08-04 Brennstoffeinspritzsystem Withdrawn EP0357247A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8820706 1988-09-01
GB888820706A GB8820706D0 (en) 1988-09-01 1988-09-01 Fuel injection systems

Publications (1)

Publication Number Publication Date
EP0357247A1 true EP0357247A1 (de) 1990-03-07

Family

ID=10643037

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89307957A Withdrawn EP0357247A1 (de) 1988-09-01 1989-08-04 Brennstoffeinspritzsystem

Country Status (3)

Country Link
EP (1) EP0357247A1 (de)
JP (1) JPH0281952A (de)
GB (1) GB8820706D0 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0467072A1 (de) * 1990-07-12 1992-01-22 MAN Nutzfahrzeuge Aktiengesellschaft Brennstoffeinspritzvorrichtung für luftverdichtende Brennkraftmaschinen
WO2005113976A1 (de) * 2004-05-18 2005-12-01 Robert Bosch Gmbh Kraftstoffeinspritzsystem
EP2662557A1 (de) * 2012-05-08 2013-11-13 Robert Bosch GmbH Verschlussbolzen mit Durchflussbegrenzer für einen Injektor

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2522705Y2 (ja) * 1990-07-13 1997-01-16 三菱自動車工業株式会社 燃料噴射ノズル
JP2522706Y2 (ja) * 1990-07-13 1997-01-16 三菱自動車工業株式会社 燃料噴射ノズル

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1014131A (en) * 1962-05-09 1965-12-22 Ricardo & Co Engineers Fuel injection apparatus for internal combustion engines
US3342422A (en) * 1964-10-26 1967-09-19 Ricardo & Co Engineers Fuel injection apparatus for internal combustion engines
FR1543814A (fr) * 1966-11-11 1968-10-25 Cav Ltd Appareil d'alimentation en combustible pour moteur à combustion interne
FR2099831A5 (de) * 1970-06-24 1972-03-17 Cav Ltd
US4165838A (en) * 1976-02-20 1979-08-28 Diesel Kiki, Co., Ltd. Fuel injection nozzle
GB2045863A (en) * 1979-03-23 1980-11-05 Daimler Benz Ag Controlling the flow of fuel to fuel injectors for internal-combustion engines
GB2054038A (en) * 1979-07-10 1981-02-11 Daimler Benz Ag Regulating the fuel flow rate to a fuel injection valve
EP0185308A1 (de) * 1984-12-15 1986-06-25 Klöckner-Humboldt-Deutz Aktiengesellschaft Brennstoffeinspritzsystem

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1014131A (en) * 1962-05-09 1965-12-22 Ricardo & Co Engineers Fuel injection apparatus for internal combustion engines
US3342422A (en) * 1964-10-26 1967-09-19 Ricardo & Co Engineers Fuel injection apparatus for internal combustion engines
FR1543814A (fr) * 1966-11-11 1968-10-25 Cav Ltd Appareil d'alimentation en combustible pour moteur à combustion interne
FR2099831A5 (de) * 1970-06-24 1972-03-17 Cav Ltd
US4165838A (en) * 1976-02-20 1979-08-28 Diesel Kiki, Co., Ltd. Fuel injection nozzle
GB2045863A (en) * 1979-03-23 1980-11-05 Daimler Benz Ag Controlling the flow of fuel to fuel injectors for internal-combustion engines
GB2054038A (en) * 1979-07-10 1981-02-11 Daimler Benz Ag Regulating the fuel flow rate to a fuel injection valve
EP0185308A1 (de) * 1984-12-15 1986-06-25 Klöckner-Humboldt-Deutz Aktiengesellschaft Brennstoffeinspritzsystem

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0467072A1 (de) * 1990-07-12 1992-01-22 MAN Nutzfahrzeuge Aktiengesellschaft Brennstoffeinspritzvorrichtung für luftverdichtende Brennkraftmaschinen
WO2005113976A1 (de) * 2004-05-18 2005-12-01 Robert Bosch Gmbh Kraftstoffeinspritzsystem
EP2662557A1 (de) * 2012-05-08 2013-11-13 Robert Bosch GmbH Verschlussbolzen mit Durchflussbegrenzer für einen Injektor
US9279403B2 (en) 2012-05-08 2016-03-08 Robert Bosch Gmbh Closure bolt for an injector

Also Published As

Publication number Publication date
JPH0281952A (ja) 1990-03-22
GB8820706D0 (en) 1988-10-05

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