GB2190426A

GB2190426A - I.C. engine electromagnetic fuel injector

Info

Publication number: GB2190426A
Application number: GB08710799A
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: DE3716429A1; IT1204628B; FR2598750A1; KR870011366A; GB8710799D0; GB2190426B; IT8720551A0

Description

GB 2 190 426 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 positioned between the valve injector having an electromagnetically operable member 19 and a plug 25A which is an interference valve including a spring biased valve member fit in the bore 18 whereby the force exerted by the which, when moved to an open position upon 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 transverse drillings 26 through which an outlet orifice. fuel can flow from the end of the passage 18. In use Fuel is supplied to the inlet at a regulated pressure when the valve member is lifted from its seating fuel the fuel generally being continuously pumped flows 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 at which fuel is supplied to the passage 18 after it has become thoroughly warm, the body of and also upon the 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 from the engine soaks into the injector and the when started the idling of the engine maybe uneven 90 residual fuel within the injector becomes heated and due to the excessively heated fuel andlor fuel it could become sufficiently hot 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 it is convenientform. 95 proposed to arrange for fuel circulation through the According to the invention a petrol injector of the nozzle. In order to achieve this the nozzle must be kind specified comprises a body assembly including provided with a fuel inlet and a fuel outlet.

a core member which defines a passage extending As shown in the drawing the end of the bore in the from the fuel inlet to adjacent the valve member and core member accommodates a division baffle 30.

a fuel return path extending from adjacent said 100 The baffle shown in Figure 1 is of hollow truncated valve member to a fuel return outlet whereby fuel form with the interiorthereof connecting with a can be circulated within the body assembly. tubular member 27 which extends with clearance Two example of petrol injector in accordance with within the bore 18 to a position adjacent the drillings the invention will now be described with reference 26. Support is provided for the tubular member 27 to the accompanying drawings each of which is a 105 and the baffle 30 by the plug 25A which has a central sectional side elevation of the respective example. drilling to accommodate the tubular member 27.

Referring to Figure 1 of the drawings the injector The open and wider end 17 of the baffle receives comprises a body assembly 10 which comprises an cool fuel from the fuel system and for convenience a outer magnetic body 11 of hollow stepped form and filter 44 is located in the baffle. Outlets 36 are within which extends a central core member 12 110 formed in the wall of the core member and open formed from magnetic material. The core member is into the bore 18 adjacent the outer surface of the provided with a flange 13 which located within the baffle 30.

open and wider end of the body and surrounding The drillings 26 open into a zone 39 from which the core member is an electrically insulating former fuel can flow through the outlet orifice 21 when the 14 upon which is wound a solenoid winding 15. 115 valve member is lifted from its seating. Surplus fuel Electrical connections 16 are provided to enable the is arranged to flow along channels 37 defined solenoid winding to be connected to a source of between the core member and the former 14, the electric supply. channels communicating by way of drillings 38 with The core member extends beyond the flange and the bore 18 at a position adjacent the plug. The latter within the core member is a stepped passage or 120 is also provided with channels 39 to allow fuel to bore 18. Adjacent the end of the core member within flow to the outlets 36.

the body 12 is a plate-like valve member 19 which is In use, when the pump of the fuel system is biased by a coiled compression spring 24 located energised fuel will flow through the inlet and within.

within the passage 18, into contact with annular seat the tubular member 27 to adjacent the valve members formed integrally with a seat ring 20. The 125 member. Fuel will return along the channels 37, the seat ring 20 defines an outlet orifice 21 which opens drillings 38 and the channels 39 to the outlets 36 and into a tubular outlet member 22 which is secured some fuel may return directly through the passage within the narrower end of the body 11. 18. The heated fuel within the nozzle will therefore The core member and an inwardly directed flange be displaced before cranking of the associated 23formed on the body 11, form the pole pieces of 130 engine to achieve starting, takes place. Even if 2 GB 2 190 426 A 2 cranking takes place before the heated fuel has been 55 and core member being formed from magnetic completely displaced, the cool fuel is delivered by material, a solenoid winding surrounding the core the tubular memberto adjacent the valve member. member, a seat ring defining an outlet orifice, the In the arrangement shown in Figure 2, the plug seat ring being mounted within one end of the body 25A and the separate baffle 30 and the tubular in spaced relationship to one end of the core member 27 are replaced by a tubular component 40. 60 member, a valve member located between the seat In the left hand portion of the drawing the end of the ring and said one end of the core member, resilient component remote from the valve member is of means biasing the valve member into contact with hollow truncated form whereas in the right hand the seat ring to close said outlet orifice, the other portion of the drawing the component is provided end of the core member extending beyond the other with an outwardly extending flange. The truncated 65 end of the body, a bore extending between the ends portion of the component and the flange provide the of the core member, the end of the bore at said other division wall between the inlet 17 and the outlet 36. end of the core member forming a fuel inlet, a The component forms the abutment for the spring division baffle located in said end of the bore, the 24, the latter engaging a step defined in the bore of baffle being formed with a tubular portion which the component. 70 extends within said bore towards the other end The end of the component 40 remote from the thereof, said outlet and said inlet being separated by inlet is of reduced diameter as shown in the inset said division baffle, channel means defined between drawing, and locates a seal member 41 which forms the core member and a former for the winding, said a seal with the bore 18 at a position below the exits channel means extending from said one end of the of the drillings 38 into the bore. With this 75 core member, and drillings connecting said channel arrangement therefore all the surplus fuel must means with said bore at a position intermediate the return to the outlets 36 by way of the channels 37 ends thereof whereby in use, fuel from said inlet can and the fuel flowing towards the valve member flow through said tubular portion and be returned from the inlet does flow through a portion of the along said channel means to said outlet.

Claims

bore 18 in the core member. As compared with the 80 3. An injector

according to Claim 2 in which said example of Figure 1 therefore there will be a slight tubular portion extends to adjacent said one end of delay before cool fuel reaches the valve member the core member and is located with clearance after the pump of the associated fuel system is within the bore.

energised. On the other hand the construction 4. An injector according to Claim 3 including a shown in Figure 2 is more robust. 85 plug mounted in the bore, the plug being positioned As an alternative to the seal member 40 the end of between said intermediate position and said outlet, the component 40 can be reduced in diameter and the plug providing support for said tubular portion extended so as to be a sliding fit within the bore 18 and defining channels with the wall of said bore intermediate the exits of the drillings 38 and the end through which the fuel can flow to said outlet.

of the core member adjacent the valve member. 90 5. An injector according to Claim 2 in which said tubular portion is in sealing engagement with the CLAIMS wall of said bore at a position between said 1. A petrol injectorfor delivering fuel to an air inlet intermediate position and said one end of the core of an engine, the injector including an electromember.

magnetically operable valve having a spring biased 95 6. An injector according to Claim 4 or Claim 5 in valve member which when moved to an open which said plug or said tubular portion form an position upon energisation of a solenoid forming abutment for a coiled compression spring which part of the injector, allows petrol to flow from an constitutes said resilient means.

inlet through an outlet orifice, the injector 7. A petrol injector for delivering fuel to an air inlet comprising a body assembly including a core 100 manifold of an engine comprising the combination member which defines a passage extending from and arrangement of parts substantially as the fuel inlet to adjacentthe valve member, and a hereinbefore described with reference to Figure 1 of fuel return path extending from adjacent said valve the accompanying drawings.

memberto a fuel return outlet whereby fuel can be 8. A petrol injector for delivering fuel to an air inlet circulated within the body assembly. 105 manifold of an engine comprising the combination
2. A petrol injectorfor delivering fuel to an air inlet and arrangement of parts substantially as of an engine comprising an outer hollow body, a hereinbefore described with reference to Figure 2 of core member extending within the body, the body the accompanying drawings.

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.