EP0731270A1 - Injecteur de combustible - Google Patents

Injecteur de combustible Download PDF

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Publication number
EP0731270A1
EP0731270A1 EP96301084A EP96301084A EP0731270A1 EP 0731270 A1 EP0731270 A1 EP 0731270A1 EP 96301084 A EP96301084 A EP 96301084A EP 96301084 A EP96301084 A EP 96301084A EP 0731270 A1 EP0731270 A1 EP 0731270A1
Authority
EP
European Patent Office
Prior art keywords
valve member
fuel
chamber
bore
fuel 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.)
Withdrawn
Application number
EP96301084A
Other languages
German (de)
English (en)
Inventor
Paul Buckley
Gordon M. Reid
John R. Jefferson
Marc-Andre Charbonnier
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 EP0731270A1 publication Critical patent/EP0731270A1/fr
Withdrawn legal-status Critical Current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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
    • F02M61/06—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series the valves being furnished at seated ends with pintle or plug shaped extensions

Definitions

  • This invention relates to a fuel injection nozzle for supplying fuel to an internal combustion engine and of the kind comprising a nozzle body defining a bore, a valve member slidable in the bore, resilient means biasing the valve member into engagement with a seating defined at one end of the bore, an outlet extending from said one end of the bore, a projection on the valve member, said projection extending beyond the seating and through said outlet and acting to control the flow area of said outlet as the valve member is lifted from the seating, a fuel inlet passage communicating with the bore adjacent the seating and a thrust area defined on the valve member, the pressure of fuel in said fuel inlet passage acting in use, on said thrust area to lift the valve member from the seating to allow fuel flow through said outlet.
  • Such a nozzle is known in the art as a pintle nozzle and as with all fuel injection nozzles of the inwardly opening type, as the valve member is lifted from the seating, the volume within the nozzle which contains fuel at high pressure increases.
  • a pintle nozzle has a high flow rate when the valve member is lifted from the seating and this together with the increase in volume results in a reduction of the fuel pressure which can in extreme cases, allow the valve member to re-close onto the seating. Even if re-closure of the valve member does not take place, the fuel may not be properly atomised. Moreover, when the valve member closes onto the seating it tends to act as a pump and displaces fuel at a low rate through the outlet into the engine with an adverse effect on engine emissions.
  • the object of the invention is to provide such a nozzle in a simple and convenient form in which the above described effects are reduced.
  • a fuel injection nozzle of the kind specified comprises a chamber defined in the nozzle body, said chamber being connected to said fuel inlet passage and having a wall which is movable with the valve member, the area of said wall being less than the thrust area of the valve member and being arranged so that as the valve member moves to the closed position the wall moves to increase the volume of the chamber and vice versa.
  • the fuel injection nozzle includes a nozzle body 10 of stepped cylindrical form which is clamped by means of a cap nut not shown, to a nozzle holder of the general type seen at 11 in Figure 5. Interposed between the nozzle holder and the nozzle body is a distance piece 12. Formed in the nozzle body is a bore 13 in which is slidably mounted a valve member 14. The valve member has a reduced end portion 15 which extends with clearance through an opening in the distance piece, and it carries a spring abutment 16 which is engaged by one end of a coiled compression spring 17.
  • valve member At its end opposite to the reduced portion the valve member is shaped for engagement with a seating 18 which is positioned upstream of an outlet in the form of an opening 19 which is more clearly seen in Figure 2.
  • the valve member and the wall of the bore adjacent the seating are of enlarged size to define a fuel inlet chamber 20 and this is connected by way of a fuel inlet passage 21 formed in the nozzle body and continuing in the distance piece and the holder, to a fuel inlet 22 seen in Figure 5, and which in use is connected to the outlet of a fuel injection pump.
  • the spring 17 is housed within a chamber 23 defined in the nozzle holder and the chamber communicates with a drain passage 24.
  • the valve member has an extension 25 which extends with clearance through the opening 19 and which is contoured so that as the valve member is lifted from its seating, the cross-sectional area of the opening 19 varies.
  • the reduced portion of the valve member within the inlet chamber 20 defines a thrust face against which the fuel pressure in the chamber can act to lift the valve member away from its seating. In use therefore when fuel is delivered from the fuel injection pump the pressure of fuel in the chamber 20 acts upon the thrust face and when the force developed is sufficient to overcome the force exerted by the spring, the valve member is lifted from its seating to allow fuel flow through the opening 19.
  • a further chamber 26 which is in communication with the fuel inlet passage 21.
  • This chamber is defined by means of a sleeve 27 which is a sliding fit on a reduced portion 14A of the valve member.
  • the sleeve 27 is located with clearance within an enlarged portion of the bore 13 and the fuel pressure within the chamber 26 urges it into sealing engagement with the end surface of the distance piece 12.
  • a light spring may be provided to ensure that it remains in engagement with the surface between the periods of fuel delivery and when the engine is not in use.
  • Part of the wall of the chamber 26 is defined by the step between the main portion of the valve member and the reduced portion 14A and in use therefore when the valve member is lifted from the seating whilst the volume of the chamber 20 increases, the volume of the chamber 26 decreases. It is to be noted however that the area of the step on the valve member which is exposed to the pressure in the chamber 26 must be less than the area of the thrust face of the valve member which is exposed to the pressure in the chamber 20. With this arrangement a weaker spring is required to maintain the valve member in engagement with the seating. As compared with the nozzle shown in Figure 1 the increase in the total volume which contains fuel at high pressure as the valve member moves to the open position, is reduced.
  • valve member 14 is provided with a counter bore 29 in which is slidably mounted a plunger 30 which by means of a thrust pin 31 which engages an end wall of the spring chamber in the holder, is restrained against movement out of the counter bore.
  • the inner end 26A of the counter bore 29 defines the further chamber and it communicates with a circumferential groove 32 which is connected to the fuel inlet passage 21.
  • the end area of the counter bore defines the aforesaid wall of the further chamber and as with the example of Figure 2, its end area must be less than that of the thrust face which is exposed to the pressure within the chamber 20.
  • the spring abutment in the example of Figure 3 is of annular form and has a skirt portion 33 for engagement with the valve member.
  • the arrangement which is shown in Figure 4 is basically the same as the arrangement shown in Figure 3 except that in this case the valve member extends with clearance through the distance piece and the spring abutment 34 is of annular form without the skirt portion.
  • the nozzle body and the distance piece are of standard form as shown in Figure 1 but in this case the spring abutment 35 is provided with an integral push rod 36 which extends into engagement with a plunger 37 slidably mounted in a bore 38 formed in the nozzle holder.
  • the end of the plunger is exposed within a chamber 26B formed by an extension of the fuel inlet 22.
  • the end area of the plunger 37 exposed to the pressure at the inlet 22 constitutes the aforesaid wall and again the area of the plunger must be less than that of the aforesaid thrust face of the valve member 14.
  • a fluted plug 39 is forced into the fuel inlet to adjacent the plunger 37.
  • the push rod 36 may be formed integrally with the plunger 37 and merely located within a recess formed in the spring abutment.
  • the rod 36 may be a separate item which is guided adjacent its opposite ends.
  • the bore 38 may be machined from the spring chamber the length of the bore being sufficient so that it just breaks into the inclined portion of the fuel inlet passage 21. In this case the end of the bore forms the stop.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
EP96301084A 1995-02-24 1996-02-16 Injecteur de combustible Withdrawn EP0731270A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9503733.9A GB9503733D0 (en) 1995-02-24 1995-02-24 Fuel injection nozzle
GB9503733 1995-02-24

Publications (1)

Publication Number Publication Date
EP0731270A1 true EP0731270A1 (fr) 1996-09-11

Family

ID=10770188

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96301084A Withdrawn EP0731270A1 (fr) 1995-02-24 1996-02-16 Injecteur de combustible

Country Status (2)

Country Link
EP (1) EP0731270A1 (fr)
GB (1) GB9503733D0 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3247833A (en) * 1962-12-03 1966-04-26 Ass Eng Ltd Fuel injection valves
DE2726300A1 (de) * 1977-06-10 1978-12-21 Bosch Gmbh Robert Kraftstoffeinspritzduese
FR2534976A1 (fr) * 1982-10-23 1984-04-27 Lucas Ind Plc Injecteur de combustible

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3247833A (en) * 1962-12-03 1966-04-26 Ass Eng Ltd Fuel injection valves
DE2726300A1 (de) * 1977-06-10 1978-12-21 Bosch Gmbh Robert Kraftstoffeinspritzduese
FR2534976A1 (fr) * 1982-10-23 1984-04-27 Lucas Ind Plc Injecteur de combustible

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 8, no. 154 (M - 310) 18 July 1984 (1984-07-18) *

Also Published As

Publication number Publication date
GB9503733D0 (en) 1995-04-12

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