EP0413454A1 - Pumpedüse - Google Patents

Pumpedüse Download PDF

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Publication number
EP0413454A1
EP0413454A1 EP90308314A EP90308314A EP0413454A1 EP 0413454 A1 EP0413454 A1 EP 0413454A1 EP 90308314 A EP90308314 A EP 90308314A EP 90308314 A EP90308314 A EP 90308314A EP 0413454 A1 EP0413454 A1 EP 0413454A1
Authority
EP
European Patent Office
Prior art keywords
plunger
fuel
cam
movement
rate
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Withdrawn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
EP90308314A
Other languages
English (en)
French (fr)
Inventor
David Sydney Lemon
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 EP0413454A1 publication Critical patent/EP0413454A1/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Withdrawn legal-status Critical Current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
    • 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
    • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
    • F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
    • F02M59/102—Mechanical drive, e.g. tappets or cams
    • 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
    • F02M45/06—Pumps peculiar thereto
    • F02M45/063—Delivery stroke of piston being divided into two or more parts, e.g. by using specially shaped cams
    • 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

Definitions

  • This invention relates to a so called unit injector system for supplying fuel to a compression ignition engine and of the kind comprising a body in which is defined a bore and in which is mounted a reciprocable plunger, a cam for actuating the plunger, the plunger and bore defining at least in part, a pumping chamber from which fuel is expelled during inward movement of the plunger, an outlet passage extending from said pumping chamber and communicating with the inlet of a fuel injection nozzle which is mounted on the body and a spill valve mounted on the body and which controls the flow of fuel through a spill passage communicating with said pumping chamber, and means through which the pumping chamber is completely filled with fuel during the outward movement of the plunger.
  • Unit injectors are well known in the art, the cam being driven by the associated engine and the operation of the spill valve being controlled by an electro-­magnetic device the supply of electric current to which is effected by an electronic control system.
  • the electro-magnetic device includes an armature which may be coupled to the valve member of the spill valve although other arrangements are known in which a servo system is provided.
  • the spill valve takes a finite time to move from its open position to the closed position and back to its open position and this means that as the speed of operation of the associated engine increases the minimum amount of fuel which can be supplied to the engine increases. At high engine speeds this minimum amount of fuel may be greater than is required to operate the engine at light load. Moreover, in some engine installations where the injection of fuel takes place in two stages, the aforesaid minimum quantity of fuel may be in excess of the desired pilot quantity of fuel at high engine speeds.
  • the object of the present invention is to provide a unit injector of the kind specified in a simple and convenient form.
  • the profile of the leading flank of the cam has a first portion which after the initial inward movement of the plunger effects inward movement of the plunger at a substantially constant rate, a second portion during which the rate of movement of the plunger is increased and a third portion during which the rate of movement of the plunger decreases until the crest of the cam is reached, the rate of movement being considered in terms of the angular rotation of the cam.
  • the unit injector comprises a body 10 which defines a stepped cylindrical portion 11 to which is secured the body 12 of a fuel injection nozzle, there being interposed between the nozzle body and the body 10, a distance member 15.
  • the valve member of the nozzle is of conventional construction and is biased to a closed position in which it contacts a seating, by means of a coiled compression spring 14 which is housed within a chamber defined in the body 10.
  • the valve member of the nozzle mounts a spring abutment 13 against which the spring 14 bears.
  • the nozzle body is retained relative to the body 10 by means of a cap nut 16 which has a skirt portion 17 in screw thread engagement with a complementary thread formed on the portion 11 of the body.
  • the body also mounts a high pressure fuel pump which is generally indicated at 18 and which includes a reciprocable plunger 19 which is housed within a bore formed in a pump barrel 20, the latter being retained within a complementary recess in the body 10 by means of a retarding nut 21.
  • the plunger is connected to a tappet assembly generally indicated at 22 and which in use is engaged by a cam 22A driven by the associated engine. The tappet assembly and plunger are moved inwardly by the cam against the action of a return spring 23.
  • a pair of filling ports 24 which communicate with a gallery surrounding the barrel and which in turn communicates with a fuel supply passage 25 which in use, communicates with a fuel supply channel formed in the wall of the bore in the associated engine, in which the unit injector is located.
  • the plunger and bore define a pump chamber which communicates by way of a passage 28, which extends through the cylindrical portion 11 of the body, and the distance piece 15 with a nozzle inlet.
  • the nozzle inlet is connected in the usual manner, with a fuel supply gallery which surrounds a part of the valve member of the nozzle and when fuel under pressure is supplied through the inlet, the fuel pressure acting upon the valve member lifts the valve member against the action of the spring 14 to permit fuel flow through an outlet orifice.
  • the flow of fuel can occur providing a spill control valve generally indicated at 29 is in the closed position.
  • the spill valve is connected to the passage 28 by a spill passage which is shown in dotted outline at 30 and when the valve 29 is open the fuel pressure in the passage 28 is insufficient to lift the valve member in the nozzle, the fuel returning by way of a passage 31 to a spill outlet 32 formed in the cylindrical portion of the body 10.
  • the spill valve is controlled by an electro-magnetic actuator which is generally indicated at 33 and the supply of current to the actuator is controlled by an electronic control system not shown.
  • the spill valve takes a finite time to move from its open position to the closed position and back to its open position and this means that for a given engine speed there is a minimum amount of fuel which can be supplied through the outlet orifice. This minimum amount increases as the engine speed increases.
  • Figure 2 illustrates at A the profile of the leading flank of such a cam lobe, it being understood that it is the leading flank which causes inward movement of the plunger.
  • Figure 3 shows at A the profile of the leading flank of a cam lobe as modified in accordance with the invention and as will be seen following initial inward movement of the plunger there is a first period B1 during which the plunger moves at a constant rate but it will be observed that in the example shown, the rate of movement of the plunger is half that obtained with the standard cam. Following the first period during which the plunger moves at a constant rate, there is a second period B2 during which the speed of the plunger increases and this is followed by a third period B3 during which the speed of the plunger is decreased as the crest of the cam lobe is approached. In the example the second portion B2 is also shaped to provide constant rate of acceleration. It will be understood that the rates quoted are by way of example only.
  • the spill valve 29 is operated during the first period B1 so that for a given spill valve operating as quickly as possible, with the cam modified in accordance with the invention a reduced minimum quantity of fuel is supplied as compared with the conventional cam.
  • the first stage of delivery or "pilot" delivery takes place during the first period B1.
  • the rate of movement of the plunger during the first period B1 is constant, it will be understood however that the rate of movement of the plunger can be arranged if so desired, to vary slightly in this period.
  • the large amount of fuel which can be delivered to the engine cylinder can cause a sharp rise in cylinder pressure.
  • the rate of supply of fuel will be less than with the conventional cam and the quantity of fuel delivered during the ignition delay period will be reduced.
  • the rate of rise of cylinder pressure will be reduced and the engine noise reduced.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
EP90308314A 1989-08-15 1990-07-30 Pumpedüse Withdrawn EP0413454A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB898918600A GB8918600D0 (en) 1989-08-15 1989-08-15 Unit injector
GB8918600 1989-08-15

Publications (1)

Publication Number Publication Date
EP0413454A1 true EP0413454A1 (de) 1991-02-20

Family

ID=10661655

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90308314A Withdrawn EP0413454A1 (de) 1989-08-15 1990-07-30 Pumpedüse

Country Status (3)

Country Link
EP (1) EP0413454A1 (de)
JP (1) JPH0388958A (de)
GB (1) GB8918600D0 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0528226A1 (de) * 1991-08-16 1993-02-24 Robert Bosch Gmbh Elektrisch gesteuerte Pumpendüse für Kraftstoffeinspritzvorrichtungen in Brennkraftmaschinen
EP0599320A1 (de) * 1992-11-27 1994-06-01 IVECO FIAT S.p.A. Einspritzdruckregeleinrichtung eines Kraftstoffeinspritzventils für Dieselmotoren
EP0613523B1 (de) * 1992-09-18 1997-04-16 General Electric Company Elektronisches kraftstoffeinspritzsystem für grosse luftverdichtende, selbstzündende brennkraftmaschinen
EP1072785A2 (de) * 1999-07-30 2001-01-31 Delphi Technologies, Inc. Kraftstoffpumpe
EP1072787A2 (de) † 1999-07-28 2001-01-31 Toyota Jidosha Kabushiki Kaisha Hochdruckkraftstoffpumpe und Nocken für Hochdruckkraftstoffpumpe
EP1055814A3 (de) * 1999-05-28 2003-07-09 Mack Trucks, Inc. Kraftstoffeinspritzsystem für ein Diesel Motor

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2591401A (en) * 1947-03-08 1952-04-01 Atlas Diesel Ab Fuel injection device
DE840477C (de) * 1941-11-16 1952-06-03 Bosch Gmbh Robert Einspritzpumpe, insbesondere fuer Brennkraftmaschinen
GB2156430A (en) * 1984-03-23 1985-10-09 Lucas Ind Plc Compression ignition engine fuel injection unit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE840477C (de) * 1941-11-16 1952-06-03 Bosch Gmbh Robert Einspritzpumpe, insbesondere fuer Brennkraftmaschinen
US2591401A (en) * 1947-03-08 1952-04-01 Atlas Diesel Ab Fuel injection device
GB2156430A (en) * 1984-03-23 1985-10-09 Lucas Ind Plc Compression ignition engine fuel injection unit

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 9, no. 98 (M-375)(1821) 27 April 1985, & JP-A-59 221455 (MITSUBISHI JUKOGYO K.K.) 13 December 1984, *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0528226A1 (de) * 1991-08-16 1993-02-24 Robert Bosch Gmbh Elektrisch gesteuerte Pumpendüse für Kraftstoffeinspritzvorrichtungen in Brennkraftmaschinen
EP0613523B1 (de) * 1992-09-18 1997-04-16 General Electric Company Elektronisches kraftstoffeinspritzsystem für grosse luftverdichtende, selbstzündende brennkraftmaschinen
EP0599320A1 (de) * 1992-11-27 1994-06-01 IVECO FIAT S.p.A. Einspritzdruckregeleinrichtung eines Kraftstoffeinspritzventils für Dieselmotoren
EP1055814A3 (de) * 1999-05-28 2003-07-09 Mack Trucks, Inc. Kraftstoffeinspritzsystem für ein Diesel Motor
EP1072787A2 (de) † 1999-07-28 2001-01-31 Toyota Jidosha Kabushiki Kaisha Hochdruckkraftstoffpumpe und Nocken für Hochdruckkraftstoffpumpe
EP1072787B2 (de) † 1999-07-28 2010-02-24 Toyota Jidosha Kabushiki Kaisha Hochdruckkraftstoffpumpe und Nocken für Hochdruckkraftstoffpumpe
EP1072785A2 (de) * 1999-07-30 2001-01-31 Delphi Technologies, Inc. Kraftstoffpumpe
EP1072785A3 (de) * 1999-07-30 2002-05-08 Delphi Technologies, Inc. Kraftstoffpumpe

Also Published As

Publication number Publication date
JPH0388958A (ja) 1991-04-15
GB8918600D0 (en) 1989-09-27

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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