US2097241A - Liquid fuel injector for internal combustion engines - Google Patents

Description

Patented Oct. 26, 1 937 arr QFICE aosaz i LIQUKD FUEL INdECTOR FOR HNZTERNAL COMBUSTEGN ENGINES England Application November 13, 1936, Serial No. 110,744

In Great Britain November 13, 1935 6 Claims.

This invention relates to liquid fuel injectors for internal combustion engines, and exclusively to those of the solid injection" type in which a charge of liquid is injected through a nozzle direct to the working space or combustion chamber of the engine without the previous admixture of air or other gas with said liquid fuel.

It is the primary object of the present invention to provide an improved construction of 19 liquid fuel injector which is particularly robust in use, and which moreover can be arranged so that the working parts are less delicate than those of the injectors at present'in use.

It is a further object of the invention to pro-- vide an injector having a valve device, the seating surfaces of which are normally protected against corrosion and overheating, said seating surfaces themselves being more capable of withstanding the constant hammering than those of the usual kind.

In a solid injection fuel injector for an internal combustion engine comprising a body with a fuel passage extending longitudinally thereof, an injection nozzle at the lower end of the body,

a spring, a slidable valve member normally closing said injection nozzle under the action of the spring but arranged to open automatically when liquid fuel at high pressure is introduced into the fuel-passage, the present invention is character- 39 ized by the fact that a concave valve seat is formed in the lower part of the valve member and coacts with a mating convex valve seat surrounding the injection nozzle. Preferably the concave ,valve seat is of conical shape, and the mating projection upon the body is in the form of a frusto-cone having an axial bore which acts as the nozzle.

The invention is illustrated by way of example in the accompanying drawing in which Figure 1 is an enlarged sectional elevation showing the construction of the lower end of a fuel injector;

Figure 2 is a sectional side elevation to a smaller scale showing a complete fuel injector. assembly;

Figure 3 is an enlarged sectional view showing the constructional details of the nozzle portion of the injector;

Figure 4 is an enlarged fragmentary section showing diagrammatically a modified arrangemerit of nozzle; and

Figure 5 is a similar view showing a. further modification.

In Figure 1 the body of the injector which can be of any known or suitable form is indicated at I 0, and is provided with a longitudinal passage l I through which liquid fuel is normally fed in the direction of the arrow by suitable pressure-producing means, such as a fuel injection pump.

A valve member 12 is slidably mounted in the 5 body l0, and at its lower end is formed with a hollow or concave seating l3 conveniently produced by shaping the lower end of the member i2 with a conical recess M. This hollow seating l3 coacts with a convex seating l5 upon the out- 10 side of a frusto-conical projection I6 formed upon or carried by the body l0, and this projection is drilled coaxlally at H and 18 so as to produce the usual nozzle through which fuel is injected into the explosion chamber of. the engine. In 5 order to simplify manufacture the lower end of the valve member I2 is reduced in diameter at l9, and the body "I is formed with an annular passage 20 communicating with the longitudinal passage ll. 20

In use the valve member 12 is normally pressed downwardly conveniently by means of a spring, and thus the injection nozzle i8 is closed. When high pressure liquid is introduced into the passage ii, however, it acts upon the two annular 25 surfaces 2! and 22 at the end of the valve memher, and thus lifts the latter, so allowing liquid to pass between the seatings l3 and IE to the injection nozzle Hi. It will be observed that as normally the injector operates in the vertical 30 position shown in the drawing, the annular recess or well 23 surrounding the projection it is normally filled with a reserve of liquid fuel, and this not only tends to cool the injection nozzle but also provides a liquid seal tending to 35 prevent the escape and damaging efiect of hot combustion gases. Moreover, it will be seen that the fuel in passing the seatings l3 and I5 is rapidly reversed in direction, and it is thought that the turbulence so brought about assists in 40 the breaking-up of the fuel spray.

A constructional example of the invention is shown in Figures 2 and 3, where the body ll) of the injector is provided at its lower end with an annular cap 26 serving to hold a nozzle fitting 5 25 in place. The body is drilled axially at 25 for the accommodation of a valve push rod 2? which coacts with a coiled compression spring 28 at its upper end, said spring in turn being supported by an adjusting screw 29 serving to regulate the force exerted by the spring 28. The screw 29 is drilled axially for the reception of a feeler rod 30, which in the knownmanner bears against the upper end of the push rod. 21 for giving an 55 indication of the manner in which the injector is working.

Fuel under high pressure is fed through a connection 3| which communicates with the iongitudinal passage II, and this in turn connects with an annular channel 32 and the nozzle-piece 25, as will be seen in Figure 3. A further longitudinal passage 33 in this fitting transmits the liquid fuel to the annular space 20, where it acts upon the end surface 22 of the valve member l2 so as to lift the latter against the action of the compression spring 28. It will be seen that the upper end of the valve member I 2 is formed with a spigot 34 which cooperates with the lower end of the push rod 21. The valve member I2 is formed with a pair of grooves 35 for the purpose of preventing leakage, and the nozzle fitting 25 is drilled at its lower end with a nozzle passage l8 in the usual manner.

Figure 4 illustrates a further modification in the construction where a plurality of nozzle passages are provided as indicated at 36 in order to provide a spray effect. Moreover, in the further modification shown in Figure 5, the annular passage 20 is of substantially triangular crosssection so as to merge with the curved wall of the frusto-conical projection l6, thus simplifying the construction of the injector.

It will be understood that the construction of the body portion of the fuel injector may be arranged in many ways other than those illustrated without detracting from the advantages derived by the use of the inverted form of valve seating.

What we claim is:

1. A solid injection fuel injector for an internal combustion engine comprising a body with a fuel passage extending longitudinally thereof, an injection nozzle at the lower end of the body, a spring, a slidable valve member normally closing said injection nozzle under the action of the spring but arranged to open automatically when liquid fuel at high pressure is introduced into the fuel passage, a concave valve seat formed in the lower part of the valve memher and a mating convex valve seating surrounding the injection nozzle.

2. A "solid injection" fuel injector for an internal combustion engine comprising a body with a fuel passage extending longitudinally thereof, an injection nozzle at the lower end of the body, a spring, a slidable valve member nor-- mally closing said injection nozzle under the action of the spring but arranged to open automatically when liquid fuel ,at high pressure is introduced into the fuel passage, a hollow of conical shape in the lower end of the valve member, and a projection of frusto-conical form having an axial bore acting as the nozzle, said hollow in-the valve member being ground so as accurately to fit over the frusto-conical projection.

3. A solid injection" fuel injector for an internal combustion engine comprising a body with a fuel passage extending longitudinally thereof, an injection nozzle at the lower end of the body, a spring, a slidable valve member normally closing said injection nozzle under the action of the spring but arranged to open automatically when liquid fuel at high pressure is introduced into the fuel passage, a raised annular valve seat surrounding the nozzle aperture and arranged to slope downwardly away therefrom to form an annular well disposed below the level of nozzle aperture, and a female valve seating within a recess in the end of the valve member adapted to mate with the raised annular seat.

4. A solid injection fuel injector for an internal combustion engine comprising a body with a fuel passage extending therethrough, an injection nozzle at the lower end of the body, a spring, a slidable valve member normally closing said injection nozzle under the action of the spring but arranged to open automatically when liquid fuel at high pressure is introduced into the fuel passage, a hollow of conical shape in the lower end of the valve member, and a projection of frusto-conical form having an axial bore acting as the nozzle, that part of the bore disposed within the projection being of relatively large diameter and the part disposed below, serving as the nozzle, being of small diameter, said hollow in the valve member being ground so as accurately to fit the frusto-conical projection.

5. A solid injection fuel injector for an internal combustion engine comprising a body with a fuel passage extending therethrough, an injection nozzle at the lower end of the body, a spring, a slidable valve member normally closing said injection nozzle under the action of the spring but arranged to open automatically when liquid fuel at high pressure is introduced into the fuel passage, a hollow in the lower. end of the valve member arranged to serve as a concave seating, a projection carried by the body and coacting with the concave seating to control the fiow of fuel into the nozzle, said fuel being caused to flow upwardly between the concave seating and the projection before entering the nozzle.

6. A "solid injection fuel injector as claimed in claim 1 in which the convex valve seat controls the supply of fuel to a plurality of nozzle P8558885.

HENRY JAMES RICHARDS. PERCY WILLIAM CARTER.

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