US2572209A - Fuel injection device - Google Patents

Description

Oct. 23, 1951 w. B. SMITS FUEL INJECTION DEVICE Filed July 1, 1948 FIGB INVENTOR WYTZE BEYE SHITS BY v I v Q AGENTS Patented Oct. 23, 1951 FUEL INJECTION DEVICE Wytze Beye Smits, Voorburg, Netherlands, assignor to Smitsvonk N. V., The Hague, Netherlands Application July 1, 1948, Serial No. 36,398 In the Netherlands July 23, 1947 2 Claims.

The invention relates to a fuel injection device having a body in which a fuel duct is formed and which is adapted to be mounted in the wall of a cylinder of an internal combustion engine.

The invention has for its object to provide, for engines operating with fuel injection and electrical ignition, one single device which is both a fuel injector and a spark plug. It consists in this that electrodes are mounted on the body of the injector near the exhaust opening of the fuel duct thereof, said electrodes being separated by insulating or semi-conductive material and provided with means for their electrical connection and said electrodes constituting together with said separating material a low tension spark plug adapted to be actuated by discharge currents of a condenser. The combination of such a fuel injection device and a spark plug of the sliding or creeping spark type appears to lead to very simple constructions.

A simple construction of the fuel injecting spark plug is obtained, when the fuel injection device is provided with the conventional needle valve, which is periodically opened by the pressure of the fuel itself, and annular electrodes are arranged coaxially with respect to said needle valve. The needle valve is adapted to be axially moved in the body of the device, and at the end of said body, at which end the fuel duct opens, the

parts of the spark plug are held together by a :2

screw ring screwed on said end of the body. At least one of the electrodes is connected to a conductor which is insulatedly passed through said body.

Instead of an injection device provided with a needle valve other known injection systems may be used. The electrodes may extend along the wall of a conical recess at the active end of said body. They may also be situated in a plane which is at right angles to the main axis of the body of the fuel injecting spark plug.

For the elucidation of the invention reference is made to the accompanying drawing in which, by way of example, three different embodiments of the invention are illustrated in part.

Figure 1 is a fragmentary sectional view, with a portion thereof in elevation, of the preferred form of the invention;

Figure 2 is a fragmentary view partly in section and partly in elevation of a modified form of the invention; and

Figure 3 is a fragmentary view partly in section and partly in elevation showing another modification of the invention.

In Figs. 1-3 of the drawing l designates the metal body of a fuel injecting spark plug. This body is so constructed that it can be screwed in the wall of the cylinder of an internal combustion engine. Mounted within the body I is an axially movable needle valve 2, which is pressed by a spring (not shown) with its conical point 3 against a seat 4. Thereby the fuel injection duct 5 is normally closed. The needle, which engages the bore 6 of the body I as a piston, closes a chamber 1. Fuel is periodically supplied through the passage 8 under higher pressure than obtains in the combustion space of the engine. The fuel periodically lifts the needle 2, so that the duct 5 is opened and fuel is injected into the cylinder of the engine.

In Fig. l a ring 9 of insulating or semi-conductive material is provided in a recess at the active end of the body I. Enclosed by this ring an annular electrode 10 of refractory electrically conductive material is mounted on the surface of that body I and contacts the latter metallically. A second annular electrode H of electrically conductive material is partly embedded in ring 9 and is separated from the electrode [0 by said ring. The annular electrode H is connected to a conductor 12, which is insulatedly passed through the body I by insulating material 13. On electrode H a ring of insulating material l4 and on the latter other rings [5 and I6 are placed. Ring [5 serves to compensate the different dilations of the various parts of the device. The spark plug built up of rings is kept assembled by a screw ring ll screwed on the end of the body I.

As soon as a spout of fuel is injected into the cylinder space a spark generated by the discharge current of a condenser is produced between the electrodes l0 and II. This spark creeps across the surface of the separating member 9.

The embodiment as shown in Fig. 2 is pro vided with a ring 18 of insulating or semi-conductive material in which the annular electrodes I9, 23 are embedded. Ring l8 snugly engages the end surface of the main body I. Just as in Fig. l the inner electrode H3 is connected to a conductor insulatedly passed through body I and the outer electrode 20 metalically contacts screw rin I! which is screwed on the end of said body.

In the embodiments according to Figs. 1 and 2 the electrodes of the spark plug are situated in or form part of the wall of a conical recess at the bottom of which the injection duct 5 terminates. In Fig. 3 the active surface of the fuel injecting spark plug is plane and at right angles to the main axis of the body I. Both annular electrodes 2|, 22 are embedded in the separating ring 23 of insulating or semi-conductive material. Said ring is mounted concentrically to the injection duct 5 and is kept in its place by the screw ring IT. The outer electrode 22 is connected to a conductor (not shown) which is insulated'ly mounted in the body I. By means of this fuel injecting spark plu the dead space in the cylinder of the engine can be restricted to a minimum.

Within the scope of the invention many other constructions are possible. A plurality of concentric electrodes may be provided. These electrodes need not have an annular shape. Other injection systems than the one shown may be used. The main feature of the invention is the combination of a fuel injection device and a spark plug in a single unit.

What I claim is:

1, A combined fuel injection device and spark plug for internal combustion engines comprising an outer body adapted to be mounted in the wall of an engine cylinder, a fuel supply duct passing through said body having an outlet opening, a valve provided in said supply duct having a seat positioned inwardly of said outlet opening, said body, duct and valve constitutin the injection device, at 'least two ring-shaped electrodes positioned coaXiall-y around the outlet opening of said supply duct and below said valve, an insulating member having at least a portion thereof positioned below said valve interposed between and mechanically connecting said electrodes, the exposed end face of said insulating member serving to support the sparks sweeping between said electrodes across said end face, means insulatedly passing through said body for the electrical connection of at least one of said electrodes, the other electrode contacting a grounded part of the device, said electrodes and said separating member constituting a condenser operated surface discharge spark plug in the form of an individual unit, and a clamping ring for securing said unit detachably to the outer body.

2. A combined fuel injection device and spark plug according to claim 1, in the active end of which a recess is formed, the fuel supply duct opening in the bottom of said recess and the individual unit, consisting of the electrodes and the insulating member, constituting at least part of the wall of said recess.

Wi'r'rzE BEi'rE SMITS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,205,422 Arnold Nov. 21, 1916 2,255,203 Wiegand Sept. 9, 1 941

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