US3433160A - Liquid fuel pumping apparatus - Google Patents

Description

March 18, 1969 K. A. w. KEMP 3,433,160

LIQUID FUEL PUMPING APPARATUS Filed Jan. 17, 1967 i? 2O '1 8 1117mm iI ncxi llh gg m 56 United States Patent 3,433,160 LIQUID FUEL PUMPING APPARATUS Kenneth Albert Walters Kemp, Ealing, London, England, assiguor to C.A.V. Limited Filed Jan. 17, 1967, Ser. No. 609,955 Claims priority, application Great Britain, Jan. 31, 1966,

4,096/ 66 US. Cl. 103-37 Int. Cl. F04b 49/02, 13/02, 49/00 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to liquid fuel pumping apparatus and of the kind comprising an injection pump having a pumping chamber from which fuel is displaced during an injection stroke of the pump, a cylinder from one end of which fuel is supplied to the pumping chamber of the pump during a filling stroke thereof, a shuttle slidable within said cylinder, the permitted excursion of said shuttle serving to determine the maximum amount of fuel which can be supplied to the pumping chamber of the injection pump, and a stop slidable in a direction substantially at right angles to the longitudinal axis of the cylinder said stop having a shaped surface against which the shuttle can bear whereby the maximum amount of fuel which can be fed to the pumping chamber is varied in accordance with the setting of said stop.

The object of this invention is to provide such an apparatus in a simple and convenient form.

According to the invention in an apparatus of the kind specified the shaped surface is formed on a part which is adjustably mounted in the stop for movement in a direction substantially parallel to the longitudinal axis of the cylinder.

In the accompanying drawings:

FIGURE 1 is a sectional side elevation of one example of a pumping apparatus in accordance with the invention, and

FIGURE 2 is a section on the line 2-2 of FIGURE 1.

Referring to the drawings there is provided a body part in which there is mounted a rotary cylindrical distributor 11 which is adapted to be driven in tme relationship with the engine. At one end of the distributor there is located an injection pump including a pair of pumping plungers 12 which are disposed within a transverse bore 13 formed in the distributor. Surrounding this end of the distributor is a cam ring 14 having formed on its internal periphery a plurality of pair of cams. Intermediate the plungers respectively and the cam ring are a pair of rollers 15 which bear upon the cam ring so that as the distributor rotates inward movement will be imparted to the plungers as the rollers ride over the cams. Intermediate the plungers the bore defines a fuel pumping chamber which is in communication with a longitudinal passage 16 formed in the distributor. At one point the passage is in communication with a radially disposed delivery passage 17 which is arranged to register in turn as the distributor rotates, with a plurality of outlet passages 18 formed in the body part. This registration of the delivery passage with an outlet passage takes place during the whole of the time the plungers 12 are moving 3,433,160 Patented Mar. 18, 1969 ice inwardly and the arrangement is such that fuel will be displaced from the pumping chamber to the outlet passages 18 in turn as the distributor rotates. The outlet passages are in use connected to injection nozzles respectively mounted on the engine.

At another point the longitudinal passage is in communication with a plurality of radially disposed inlet passages 19 formed in the distributor and which can communicate in turn with an inlet port 20 formed in the body part. This communication takes place whilst the delivery passage 17 is out of register with the outlet passages 18 and during this time fuel flows from the inlet port 20 to the pumping chamber of the injection pump, to provide a fresh charge of fuel for the next injection stroke of the injection pump. The inlet port is in constant communication with one end of a cylinder 21 formed in the body part and mounted within the cylinder is a cylindrical and movable shuttle 22.

Also provided is a vane type feed pump 23 the rotor of which is formed integrally with the distributor at the end thereof remote from the transverse bore. The feed pump is provided with an inlet 24 which in use, is connected to a reservoir of fuel and an outlet 25. Moreover, the outlet pressure of the feed pump is controlled by any convenient valve so that the output pressure of the feed pump varies in a manner dependent upon the speed at which the distributor and hence the engine rotates.

The outlet 25 of the feed pump is in communication with a circumferential groove 26 formed in the periphery of the distributor and this is additionally in communication with the inner end of a cylindrical cavity which contains an angularly adjustable throttle member 27. The setting of this can be varied by means of a speed sensitive governor in a well known manner. The throttle member functions 'by varying the effective size of a port 28 formed in the wall of the cavity and this port is in communication with a further circumferential groove 29 formed in the periphery of the distributor. From the groove 29 extend a plurality of longitudinal grooves 30 and these are of a length so that they can register with the inlet port 20 and are alternately arranged with the passages 19.

When one of the grooves 30 registers with the inlet port 20 fuel flows into the cylinder 21 and the shuttle 22 is moved outwardly. During the outward movement of the shuttle 22 fuel flows from the end of the cylinder 21 remote from the inlet port by way of a passage 31, and grooves 32 formed in the periphery of the distributor to drain space within the apparatus. Surplus fuel from this space can leave the apparatus by way of an outlet 33. As the distributor rotates one of the inlet passages 19 moves into register with the inlet port 20 and fuel under pressure from the outlet 25 of the pump flows to the end of the cylinder 21 remote from the inlet port by way of a passage 34 and grooves 35 on the distributor the latter extendng from the circumferential grove 26. The pressure of fuel moves the shuttle 22 towards the inlet port and the previously throttled quantity of fuel is displaced to the pumping space of the injection pump.

In order tolimit the maximum quantity of fuel which can be supplied to the engine a stop is provided to limit the excursion of the shuttle 22 away from said one end of the cylinder. It has been found that it is desirable to vary the maximum quantity of fuel which can be supplied to the engine in a manner which depends upon the speed of the engine and for this purpose the stop takes the form of a fluid pressure operable piston 36 which is accommodated and movable within a cylindrical chamber 37 disposed substantially at right angles to the longitudinal axis of the cylinder 21 containing the shuttle. The piston is loaded towards one end of the chamber by coiled compression springs 38 and is movable against the action of the springs by fuel under pressure from the outlet 25 of the feed pump supplied to the one end of the chamber through a passage 39, fuel leaving the other end of the chamber by way of a passage 40.

In the piston 36 is formed a tranverse bore in which is mounted a part 41 which can be moved relative to the piston in a direction substantially parallel to the axis of the cylinder 21 but which is fixed against angular movement by a pin which slides within a groove in the wall of the bore. The end surface of the part 41 which is presented to the shuttle defines a shaped surface 50 against which the end of the shuttle can strike. The surface is suitably shaped so that for instance as the piston 36 is moved against the action of its springs the permitted movement of the shuttle away from said one end of its cylinder is reduced. The other end of the part bears against the fiat head of an adjusting screw 42 which can be adjusted from the exterior of the apparatus, so that during movement of the piston no relative movement of the part relative to the piston occurs. By this means the maximum quantity of fuel which can be supplied to the engine is controlled and moreover by altering the setting of the adjusting screw 42 the apparatus can be adjusted quickly to suit a particular engine or a particular type of engine. In addition when manufacturing the apparatus it is only necessary to produce a range of such parts 41 to enable the apparatus to be used to supply fuel a different types of engines. Furthermore, for starting purposes the surface may be so shaped that an extra quantity of fuel can be supplied to the engine.

Having thus described my invention What I claim as new and desire to secure by Letters Patent is:

1. A liquid fuel pumping apparatus of the kind comprising in combination, a body part, an injection pump mounted within the body part and having a pumping chamber from which fuel is dsplaced during an injection stroke of the pump, a cylinder formed in the body part, passage means through which one end of the cylinder is placed in communication with the pumping chamber of the injection pump during a filling stroke thereof, a shuttle slidably mounted within said cylinder, the permitted excursion of said shuttle serving to determine the maximum quantity of fuel which can be supplied to the injection pump during a filling stroke thereof, a further cylinder formed in the body part, the longitudinal axis of said 4 further cylinder being disposed substantially at right angles to the longitudinal axis of the first mentioned cylinder, a fluid pressure operable piston mounted in the further cylinder, a part slidably mounted within a bore formed in the piston said part being slidable in a direction substantially parallel to the axis of the first mentioned cylinder, a shaped surface formed on the end of the part which is directed towards the shuttle, the adjacent end of the shuttle in use, contacting the shaped surface to limit its extent of movement, and adjusting means operable from the exterior of the body part whereby the relative setting of the part and the piston can be adjusted the arrangement being that the axial position of the piston within its cylinder determines the extent of movement of the shuttle, the extent of movement of the shuttle for a given position of the piston being adjustable by said adjusting means.

2. A liquid fuel pumping apparatus according to claim 1 in which the adjusting means comprises a screw operable from the exterior of the body part and which bears against the end of the part remote from that end which is formed with the shaped surface.

3. A liquid fuel pumping apparatus according to claim 2 in which the part is restrained against angular moveanent in the bore by a pin connected to the part and slidable within an axial groove formed in the wall of the bore.

References Cited UNITED STATES PATENTS 2,539,085 1/1951 Kerseg 74-110 2,650,571 l/1953 Mitchell 92l38 3,107,661 10/1963 Wemp 10341 X 3,292,546 12/ 1966 Evans 103--2 2,965,073 12/1960 Alfieri 74-110 X FOREIGN PATENTS 1,253,386 12/1959 France.

968,877 9/ 1964 Great Britain.

WILLIAM L. FREEH, Primary Examiner.

US. Cl. X.R.

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