GB2190427A

GB2190427A - Electromagnetic i.c. engine fuel injector

Info

Publication number: GB2190427A
Application number: GB08710800A
Authority: GB
Inventors: Paul Stuart Renowden; John Herbert Kenning; Ian Scott Johnson
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1986-05-16
Filing date: 1987-05-07
Publication date: 1987-11-18
Also published as: IT1204630B; JPS6325365A; FR2598751A1; KR870011365A; GB2190427B; GB8710800D0; GB8611949D0; JPS6325367A; US4807812A; DE3716403A1; IT8720553A0

Description

GB 2 190 427 A 1

SPECIFICATION the solenoid and the valve member 19 is formed

Fuel injectors from magnetic material so that when the solenoid is energised the valve member is lifted from the seat This invention relates to petrol injectors for member against the action of the spring.

delivering fuel to an air inlet of an engine, the 70 The spring is located in the passage 18 between injector including an electromagnetically operable the valve member 19 and a plug 25 which is an valve incorporating a spring biased valve member interference fit in the bore 18 whereby the force which, when moved to an open position upon exerted by the spring can be adjusted.

energisation of a solenoid forming part of the The core member adjacent the valve member is injector, allows petrol to flow from an inlet through 75 provided with transyerse drillings 26 through which an outlet orifice. fuel can flow. In use when the valve member is lifted Fuel is supplied to the inlet at a regulated pressure from the seat members fuel flows from the inlet the fuel generally being continuously pumped through the drillings 26, apertures in the valve around a fuel circuit to which the inlet of the injector member and through the outlet 21. The quantity of is connected. The amount of fuel supplied through 80 fuel flowing depends upon the duration of the the injector in normal use depends upon the energising pulse which is applied to the solenoid duration of the electrical energising pulse applied to winding but in addition it does depend on the the solenoid. When the engine has been stopped pressure of fuel at the inlet and also upon the after it has become thoroughly warm, the body of density of the fuel.

the injector absorbs heat particularly from the inlet 85 Since the injector is mounted on the inlet manifold and because there is a residual amount of manifold of the engine it will in normal use remain fuel in the injector, this fuel becomes heated and fairly cool as also will the fuel which is supplied to it.

may vaporize. In these circumstances it is When however the associated engine is stopped, sometimes difficult to restart the engine and even heat f rom the engine soaks into the injector and the when started the idling of the engine may be uneven 90 residual fuel within the injector becomes heated and due to the excessively heated fuel andlor fuel it may become sufficiently heated to vaporize.

vapour. In order to try to ensure that the fuel supplied The object of the present invention is to provide through the nozzle when an attempt is made to an injector of the kind specified in a simple and restart a hot engine, is as cool as possible there is convenientform. 95 provided in the passage 18 a tubular member 27 According to the invention a petrol injector of the which extends with clearance within the passage 18 kind specified includes a body assembly which to adjacent the transverse drillings 26. The tubular defines a passage extending from the fuel inlet to member is carried by the plug 25 and the effect of adjacent the valve member, the passage the tubular member is to transport fuel from the accommodating a tubular member which extends 100 inlet 17 to the drillings 26 without the fuel coming with clearance within said passage, said tubular into contact with the hot core member 12. The fuel member forming the fuel conveying path from said supplied to the inlet 17 will be comparatively cool inlet to adjacent the valve member. because it is constantly circulated through a fuel In the accompanying drawings the two figures circuit which may also include the fuel supply tank.

show in sectional side elevation two examples of 105 Figure 2 of the drawings shows a modification in petrol injector in accordance with the invention. which in addition to the tubular member 27, Referring to Figure 1 of the drawings the injector passage 28 are provided between the core member comprises a body assembly 10 which comprises an 12 and the former 14. These passages extend from outer magnetic body 11 of hollow stepped form and adjacent the transverse drillings 26 and reconnect within which extends a central core member 12. The 110 with the passage 18 at a position close to the plug core member is formed from magnetic material and 25A. The plug 25A is modified to provide a series of is provided with a flange 13 which locates within the channels 29 which connect with the passages 28 open and wider end of the body. Surrounding the and the arrangement is such that when the engine core member is an electrically insulating former 14 has been stopped, convection currents will flow and upon which is wound a solenoid winding 15. 115 cause circulation of the fuel downwardly through Electrical connections 16 are provided to enable the the tubular member 27 and upwardly through the solenoid winding to be connected to a source of passages 28 and channels 29. This circulation of electric supply. fuel, which is entirely due to convection, will act to The core member.3xtends beyond the flange to prevent local excessive heating of the fuel, define a fuel inlet 17 and within the core member is 120 particularly the fuel which is in the region of the a stepped passage 18 which extends from the inlet valve member 19. As soon as an attempt is made to to adjacent a plate-like valve member 19 which is start the engine cool fuel from the inlet will again be biased by a coiled compress:in spring 24 located deliveredt, Ajacent the valve member through the within the passage 18, into contact with annular seat tubular me-,ber 27.

members formed integrally with a seat ring 20. The 125

Claims

seat ring 20 defines an outlet orifice 21 which open CLAIMS into a tubular

outlet member 22 which is secured 1. A petrol injector for delivering fuel to an air inlet within the narrower end of the body 11. of an engine, the injector including an The core member and an inwardly directed flange electromagnetically operable valve incorporating a 23formed on the body 11, form the pole pieces of 130 spring biased valve member which when moved to 2 GB 2 190 427 A 2 an open position upon energisation of a solenoid inlet to adjacent said valve member when said forming part of the injector, allows petrol to flow solenoid is energised to lift the valve member from from an inlet through an outlet orifice, the injector said seat ring.

further including a body assembly which defines a 35 3. An injector according to Claim 2 in which said passage extending from the fuel inlet to adjacent the tubular member is located within the spring and is valve member, and the fuel inlet to adjacent the carried by said spring abutment.

valve member, and the passage accommodating a 4. An injector according to Claim 3 including tubular member extending with clearance within transverse drillings formed in said core member said passage, said tubular member forming the fuel 40 adjacent said valve member.

conveying path from said inlet to adjacent the valve 5. An injector according to Claim 4 including member. passages defined between the exterior surface of
2. A petrol injector for delivering fuel to an air inlet the core member and the solenoid, said passages at manifold of an engine, the injector comprising an one end communicating with said transverse outer hollow body, a core member extending within 45 drillings respectively and at their other ends the body, the body and core member being formed communicating with the first mentioned passage in from magnetic material, a solenoid winding the core member and channels formed in the surrounding the core member, a seat ring defining abutment to permit fuel to circulate due to an outlet orifice, the seat ring being mounted in one convection, along said passages thereby to end of the body in spaced relationship to one end of 50 minimise excessive local heating of the fuel in the the core member, a valve member located between injector.

the seat ring and said one end of the core member, a 6. A petrol injector for delivering fuel to an air inlet passage extending between the ends of the core of an engine comprising the combination and member, the other end of the core member definin g arrangement of parts substantially as hereinbefore a fuel inlet, a coiled compression spring located in 55 described with reference to Figure 1 of the said passage, one end of the spring engaging said accompanying drawings.

valve member to urge the valve member into 7. A petrol injector for delivering fuel to an air inlet sealing engagement with said seat ring, the other of an engine comprising the combination and end of the spring engaging a spring abutment arrangement of parts substantially as hereinbefore mounted in said passage and a tubular member 60 described with reference to Figure 2 of the extending with clearance within said passage, said accompanying drawings.

tubular member acting to convey fuel from said fuel Printed for Her Majesty's Stationery Office by Courier Press, Leamington Spa, 11187. Demand No. 8991685.

Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.

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