GB2148388A

GB2148388A - Electromagnetic gasoline injector

Info

Publication number: GB2148388A
Application number: GB08424073A
Authority: GB
Inventors: Michael John Forst
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1983-10-25
Filing date: 1984-09-24
Publication date: 1985-05-30
Also published as: GB8328510D0; GB8424073D0

Abstract

A valve seat member 19 is provided with a central port 21 and a valve plate 23 is urged into contact with a seat 22 surrounding the port, to prevent flow of gasoline through the port. The valve plate is attracted away from the seat member when a solenoid 16 is energised. An extension 28 extends away from the side of the seat member remote from the valve plate and has a bore 27 formed therein which terminates in a pair of outlet orifices 29. The orifices when fuel flows through the bore produce two jets which in use are directed into the respective air inlet passages leading to two inlet valves of an engine cylinder. The bore 27 may contain an insert (30, Fig. 4) to reduce its effective volume. <IMAGE>

Description

SPECIFICATION Gasoline injector This invention relates to a gasoline injector for delivering fuel to an air inlet passage of a spark ignition engine, the injector being of the kind comprising a valve seat member defining a central port through which fuel can flow from a fuel inlet, a valve plate biased into contact with the valve seat member to prevent fuel flow through the port, said valve plate being formed from magnetic material and a solenoid which can be energised to effect movement of the valve plate away from the valve seat member thereby to allow fuel flow through said port.

In known forms of injector the aforesaid port has constituted an orifice from which in use, issues a jet of fuel which is directed into an air inlet passage of an engine to mix with the air flowing therein. Usually the injector is positioned so that the fuel jet is directed towards an inlet valve of the engine so that in an engine installation there would be as many injectors as there are air inlet valves.

Engines are now being designed and manufactured which have two inlet valves per engine cylinder with the result that the number of injectors required should in accordance with established practice, be doubled. This would be uneconomic and the object of the present invention is to provide an injector of the kind specified in a form in which at least two jets of fuel are produced by the injector.

According to the invention an injector of the kind specified includes an extension formed integrally with or located against the surface of the valve seat member remote from the valve plate, a bore formed in said extension, said port opening into said bore and at least two outlet orifices extending from said bore to the peripheral surface of said extension and through which when said valve plate is lifted from the seating, fuel can flow to form at least two jets of fuel.

In the accompanying drawings: Figure 1 is a sectional side elevation of one example of an injector in accordance with the invention, Figure 2 is a view to an enlarged scale of part of the injector seen in Fig. 1, Figure 3 shows a modification to two parts of the injector seen in Fig. 1, and Figure 4 shows in section, a modification which can be applied to the injector of Fig. 1 or to the injector of Fig. 1 as modified by Fig.

3.

Referring to the drawings the injector comprises a hollow generally cylindrical outer body 11 formed from magnetic material and defining a gasoline inlet 1 2 at one end thereof. Within the body there extends a magnetic and hollow flanged core 1 3 through which extends a passage 14. Surrounding the core 1 3 is a former 1 5 formed from synthetic resin material and upon which is wound a solenoid winding 1 6.

The body 11 defines an integral radially inwardly extending circumferential shoulder 1 7 against which is located a steel annulus 18 which is trapped by a steel vavle seat member 1 9. The seat member 1 9 is itself retained in position within an open end of the body, by means of a hollow cylindrical member 20 which is secured within the open end of the body in any convenient manner. The valve seat member 1 9 is in the form of a disc having a centrally disposed port 21.The core 1 3 terminates in the same radial plane as the shoulder 1 7 and an annular clearance exists between the core and the inner face of the shoulder 1 7. The face of the seat member 1 9 which is presented to the end of the core 1 3 is shaped to provide an annular seating 22 about the port 21. Located within the annulus 1 8 between the seat member 1 9 and the end of the core 1 3 is a valve plate 23 formed from magnetisable material. The valve plate is in the form of a disc slidably received within the annulus 1 8 and having extending therethrough a plurality of apertures 24 which are arranged in a circular row about the central axis of the plate.The mean diameter of the circular row of apertures 24 is such that the apertures lie outside the seating 22 and a compression spring 25 housed within the passage 14, urges the valve plate 23 into engagement with the seating 22. This is the closed position of the injector since engagement of the valve plate with the seating prevents flow of fuel between the inlet 1 2 through the port 21.

The internal diameter of the shoulder 1 7 is less than the diameter of the annulus 1 8 and the shoulder therefore overlies the outer peripheral portion of the valve plate 23. When therefore the winding is energised the valve plate is attracted towards the shoulder and the end of the core 1 3. The thickness of the valve plate 23 is less than the thickness of the annulus 1 8 by a predetermind amount thereby to permit the valve plate to move by said predetermind amount. The movement of the valve plate is arrested by the shoulder and when in this position, fuel can flow through the passage in the part 13, across the upper face of the valve plate 23, through the apertures 24, beneath the valve plate 23 and over the top of the seating 22 through the port 21.

When the solenoid winding 1 6 is de-energised the spring 25 returns the valve plate to its closed position in engagement with the seating 22 and in order to minimise the risk of the valve plate tilting as it closes onto the seating 22 a further annular rib 26 is provided on the valve seat member, the rib being disposed outwardly of the seating.

In order to ensure that the valve plate 23 returns quickly to its closed position when the solenoid is de-energised, a non-magnetic spacer 27A is placed between the shoulder 1 7 and the valve plate 1 8. The spacer prevents contact between the valve plate and the shoulder and thus improves the "drop off" characteristic of the valve.

The fuel which passes through the port 21 flows into a bore 27 formed in an extension 28 which is secured within the hollow cylindrical member 20. The bore 27 extends towards the end of the extension remote from the valve seat member and from the end of the bore extends a pair of outlet orifices 29.

In use therefore when the valve plate is lifted from the seating 22, fuel will flow through the outlet orifices to form two penetrative jets of fuel. These jets of fuel in the use of the injector, are directed into the air inlet passages leading up to the two valves of an engine cylinder and as a result only one injector need be provided for each cylinder of the engine.

In the modified construction which is shown in Fig. 3, the extension and the valve seat member are formed integrally. In all other ways the single component is identical to the two components it replaces. Fig. 3 shows also that the end face of the extension is of conical form and the orifices 29 are positioned relative to each other so that they are disposed substantially at right angles to the exterior surface of the extension. The actual angle employed depends upon the engine installation.

It is desirable that the maximum pressure drop should occur across the orifices 29 so as to achieve proper fuel jet formation. The bore 27 does however have a substantial volume which would tend to impair formation of a satisfactory jet and it would also act as a storage chamber from which fuel could dribble between fuel deliveries or at least when the engine has been stopped. In order to minimise the aforesaid volume the bore can be provided with an insert 30 as shown in Fig. 4, the insert being formed from suitable fuel resistant material and having a crosssection such that a substantial part of the bore is filled.

As an alternative (not shown) the hollow cylindrical member 20, the valve seat member and the extension28 can be formed from a single piece of material.

Claims

1. A gasoline injector for delivering fuel to an air inlet passage of a spark ignition engine, the injector being of the kind comprising a valve seat member defining a central port through which fuel can flow from a fuel inlet, a valve plate biased into contact with the valve seat member to prevent fuel flow through the port, said valve plate being formed from magnetic material, a solenoid which can be energised ta effect movement of the valve plate away from the valve seat member thereby to allow fuel flow through said port, an extension formed integrally with or located against the surface of the valve seat member remote from the valve plate, a bore formed in said extension, said port opening into said bore and at least two outlet orifices extending from said bore to the peripheral surface of said extension and through which when said valve plate is lifted from the seating, fuel can flow to form at least two jets of fuel.

2. A gasoline injector according to Claim 1 including an insert located in said bore, said insert having a cross-section such that a substantial part of said bore is filled, said insert being formed from fuel resistant material.

3. A gasoline injector for delivering fuel to an air inlet passage of a spark ignition engine comprising the combination and arrangement of parts substantially as hereinbefore described with reference to the accompanying drawings.