GB2199077A - Gasoline injector - Google Patents

Abstract

A plate-like valve member has a depression 42 in one face in which locates a spring biasing the valve member into contact with a seating. The valve member is lifted away from the seating member by magnetic forces to allow fuel flow through an outlet. The seat member during movement tends to displace duel and the fuel displacement slows the opening of the valve member. This is counteracted by providing passages 45 which communicate with the depression and may open into a recess defined in the face of the valve member presented to the sealing. Fuel can flow through the passages 45 to minimise the resistance to movement of the valve members. The passages may take various forms (Figs. 3 to 8). <IMAGE>

Description

"GASOLINE INJECTOR" This invention relates to a gasoline injector for supplying fuel to an internal combustion engine, the injector being of the kind comprising a central hollow magnetic core member having one end connected in use to a source of fuel, a hollow body formed from magnetic material and surrounding the core member in spaced relationship, said body defining an annular pole face which extends inwardly towards the other end of the core member, the end face of which defines a further pole face, a winding which in use can be energised to cause said pole faces to assume opposite magnetic polarity, a seat member spaced from said pole faces, said seat member surrounding an outlet opening, a plate-like valve member formed from magnetic material located with clearance between said seat member and said pole faces and resilient means acting on said valve member to urge the valve member into contact with the seat member, said valve member being lifted from the seat member by magnetic forces when said winding is energised, to allow fuel flow through the outlet opening.

Such injectors are well known in the art and the main desiderata for such an injector are that the valve member should lift as quickly and as consistently as possible upon energisation of the winding.

In known injectors the valve member is provided with a central depression in its surface presented to the pole faces and also with through apertures which of necessity are disposed outside the seat member and through which fuel can flow to the outlet opening when the valve member is in the open position. During the displacement of the valve member towards the pole faces, the central zone of the valve member tends to displace fuel which has to flow outwardly along the surface of the valve member presented to the core member and/or into the hollow interior of the core member. The displacement of fuel in the manner described tends to retard the opening of the valve member.

The object of the present invention is to provide an injector of the kind specified in a simple and convenient form.

According to the invention in an injector of the kind specified the valve member defines a central depression to locate one end of a coiled spring forming said resilient means and the valve member defines a flow channel or channels extending from said depression and along which fuel can flow at least during the displacement of the valve member.

In the accompanying drawings: Figure 1 is a sectional side elevation of one example of an injector to which the invention may be applied and the remaining figures each show to an enlarged scale, three views of valve members respectively in accordance with the invention.

Referring to Figure 1 of the drawings the injector comprises a body assembly 10 which comprises an outer body 11 of hollow stepped form within which extends a central core member 12 the latter being provided with a flange 13 which locates within the open and wider end of the body 11. Surrounding the core member is an electrically insulating former 14 upon which is wound a solenoid winding 15. Electrical connections 16 are provided to enable the solenoid winding to be connected to a source of electric supply.

The core member extends beyond the flange to define a fuel inlet 17 and within the core member is a passage 18 which extends from the inlet 17 to a plate-like valve member 19 which is guided for movement by a guide ring. The valve member 19 is biased by a coiled compression spring 19A housed within the passage 18, into contact with inner and outer annular seat members 20A formed integrally with a seat ring 20 which defines an outlet orifice 21 opening into a tubular outlet member 22 which is secured within the narrower end of the body 11. As will be seen from Figure 1 the face of the valve member which is presented to the core member is provided with a depression which locates the adjacent end of the spring 19A.

The core member 12 and an inwardly directed flange 23 formed on the body 11 form the pole pieces of the solenoid with the pole faces being presented to the valve member. The valve member is formed from magnetic material so that when the solenoid winding is energised, the valve member is lifted from the seat members against the action of the spring 19A by the magnetic forces.

The spring 19A is located in the passage 18 between the valve member 19 and a tubular plug 32.

The plug 32 is retained within the core member in any convenient manner and provides the communication between the inlet 17 and the lower portion of the passage 18.

When the solenoid is energised the valve member is drawn by the magnetic forces towards the pole faces and fuel is displaced by the valve member. This displacement of fuel as described earlier in the specification, can impede the movement of the valve member and it is therefore proposed to modify the valve member in various ways as shown in the remaining figures.

In each of these figures the left hand view is a view of the surface of the valve member which is presented to the pole faces and the right hand view is a view of the surface of the valve member presented to the seat members whilst the central view is a section along the indicated line.

In Figure 2 of the drawings, the reference numeral 42 indicates the depression which is provided in the surface of the valve member presented to the pole faces, for the reception of the end of the spring 19A.

It will be noted that the surface of the valve member which is presented to the seat members defines a central portion 46 and a rim portion 47. The central portion co-operates with the inner seat member 20A to prevent fuel flow through the outlet orifice when the valve member is in the closed position. Intermediate the portions 46 and 47, the surface is recessed to lighten the valve member and the depression 42 is in communication with the recess defined between the portions 46 and 47 by way of passages 45.

In operation as the valve member is moved by the magnetic forces towards the pole faces fuel displaced by the central portion of the valve member can flow along the passages 45 thereby facilitating the movement of the valve member. When the valve member is in the open position the main flow of fuel also takes place through the passages 45 from the passage 18.

In the example of Figure 3 the surface of the valve member presented to the pole faces is provided with four slots 43 arranged in cruciform manner, the slots extending from adjacent the periphery of the valve member. The valve member is also provided with openings 44 through which fuel flows when the valve member is in the open position. The openings extend through the valve member from the base walls of the slots 43 intermediate the ends thereof. When the valve member is moved by the magnetic forces fuel displaced by the central portion of the valve member can flow along the slots 43 to facilitate movement of the valve member.

In the example of valve member shown in Figure 4, the same reference numerals as are used in Figure 3, are utilised where possible. In this case the openings 48 are of circular shape and converge inwardly towards the surface of the valve member which is presented to the seat member. The slots 43 are again provided as in the example of Figure 3 and as with the example of Figure 3, the face of the valve member which is presented to the seat member is recessed between the central portion 46 and the rim portion 47.

In the valve member which is shown in Figure 5 the openings 49 are of a pear shaped section throughout their length. It will be noted however that they do communicate with the depression 42 so that as with the previous examples, as the valve member is displaced by the magnetic forces, fuel can flow from the depression into the openings 49.

In the example shown in Figure 6 circular openings 50 extend between the opposite faces of the valve member. In addition, the slots 44 are provided which extend to the openings 50 at their outer ends and portions 51 of the slots extend through the valve member to form additional openings.

In the example shown in Figure 7 circular openings 52 extend through the valve member, the openings 52 being of substantial size. In addition, further openings 53 extend from the periphery of the depression 42 and open into an annular recess 54 defined in the face of the valve member which is presented to the seat member. It will be noted that the recess 54 breaks into the main openings 52.

Figure 8 shows a modification of the valve member shown in Figure 7 in which the openings 53 are replaced by short passages 55 which extend from a recess 56 formed in the base wall of the depression 42. The passages 55 open into the annular recess 54.

Claims (7)

1. A gasoline injector for supplying fuel to an internal combustion engine, the injector comprising a central hollow magnetic core member having one end connected in use to a source of fuel, a hollow body formed from magnetic material and surrounding the core member in spaced relationship, said body defining an annular pole face which extends inwardly towards the other end of the core member, the end face of which defines a further pole face, a winding which in use can be energised to cause said pole faces to assume opposite magnetic polarity, a seat member spaced from said pole faces, said seat member surrounding an outlet opening, a plate-like valve member formed from magnetic material located with clearance between said seat member and said pole faces, resilient means acting on said valve member to urge the valve member into contact with the seat member, said valve member being lifted from the seat member by magnetic forces when said winding is energised, to allow fuel flow through the outlet opening, said valve member defining a control depression to locate one end of a coiled spring forming said resilient means and the valve member defines a flow channel or channels extending from said depression and along which fuel can flow at least during the displacement of the valve member.

2. An injector according to Claim 1 including a slot in the face of the valve member in which said depression is formed, said slot extending outwardly from said depression and an opening extending from said slot to the other face of the valve member, said opening being positioned on the outer side of said seat member.

3. An injector according to Claim 2 in which said opening inclines inwardly towards the axis of the valve member.

4. An injector according to Claim 1 including passages communicating with said depression, said passages opening onto the face of the face of the valve member presented to the set member, said passages opening into an annular recess formed in said face and located on the outer side of said seat member.

5. An injector according to Claim 4 including openings extending through the valve member and communicating with said recess.

6. An injector according to Claim 1 including openings extending between the opposite faces of the valve member, said openings communicating with said depression.

7. A gasoline injector for supplying fuel to an internal combustion engine comprising the combination and arrangement of parts substantially as hereinbefore described with reference to Figure 1 as modified by Figure 2, 3, 4, 5, 6, 7, or 8 of the accompanying drawings.