US3663123A

US3663123A - Liquid fuel injection pumping apparatus

Info

Publication number: US3663123A
Application number: US62972A
Authority: US
Inventors: Ivor Fenne
Original assignee: CAV Ltd
Current assignee: CAV Ltd
Priority date: 1969-08-11
Filing date: 1970-08-11
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16
Also published as: DE7028410U; DE2037485A1; FR2056862A5; GB1313496A

Abstract

A liquid fuel pumping apparatus for internal combustion engines and which includes a bore which accommodates a reciprocable pumping plunger and which defines a pumping chamber from which extends an outlet. The apparatus also includes a cylinder in which is located a resiliently loaded piston, one end of the cylinder being arranged to be brought into communication with the pumping chamber after the plunger has attained a predetermined position during its injection stroke. In this manner further flow of fuel through the outlet is prevented and relief of the pressure in any apparatus associated with the outlet is obtained.

Description

Unlted States Patent [151 3,663,123 Fenne May 16, 1972 [54] LIQUID FUEL INJECTION PUMPING 3,115,838 12/1963 Eoesjter "jig/2g;

3,146,715 9/1964 nu son APPARATUS 3,465,679 9/1969 Adey et a1 ..4l7/284 [72] Inventor: Ivor Fenne, Greenford, England Primary Examiner-William L. Freeh [73] Ass1gnee: C. A. V. Llmlted, B1rm1ngham, England A"0mey Holman & Stem 22 Filed: Aug. 11, 1970 [57] ABSTRACT 21 A 1.N 62 972 l 1 pp 0 A liquid fuel pumping apparatus for internal combustion engines and which includes a bore which accommodates a [30] Foreign Application Priority Data reciprocable pumping plunger and which defines a pumping chamber from which extends an outlet. The apparatus also in- Aug. 1 1, 1969 Great Brltaln ..4Q,010/69 cludes a cylinder in which is located a resi'icmly loaded piston, one end of the cylinder being arranged to be brought U.S. into communicafion with the chamber after the [51 Int. Cl ..F04b 49/00 plunger has attained a predetermined position during its injec- [58] Field of Search ..4l7/284, 289, 274, 462, 540, tion stroke. In this manner further flow of fuel through the 417/542 outlet is prevented and relief of the pressure in any apparatus associated with the outlet is obtained.

6 [5 1 References and 5 Claims, 1 Drawing Figure UNITED STATES PATENTS 2,833,218 5/1958 Evans ..4l7/274 LIQUID FUEL INJECTION PUMPING APPARATUS This invention relates to liquid fuel injection pumping apparatus for internal combustion engines and of the kind comprising in combination, a bore, a reciprocable pumping plunger mounted within said here and an outlet from the pumping chamber defined by the bore and the plunger, said outlet in use, communicating with an injector mounted on he associated engine.

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

According to the invention an apparatus of the kind specified comprises a cylinder, a resiliently loaded shuttle mounted in said cylinder, a spill path from said pumping chamber, said spill path communicating with one end of said cylinder, flow of fuel through said spill path occuring during a pumping stroke of the plunger and being controlled by the plunger, the fuel flowing into said cylinder acting to urge the shuttle against the action of its resilient loading and valve means operable to allow the fuel contained in the cylinder to be returned to the pumping chamber during the next filling stroke of the plunger.

One example of a liquid fuel injection pumping apparatus in accordance with the invention will now be described with reference to the accompanying drawing which shows such an apparatus in schematic detail only.

Referring to the drawing there is provided a body part in which is mounted a rotary cylindrical distributor member 11. The distributor member is arranged to be driven in timed relationship with an engine to which fuel is supplied by the apparatus and at one end of the distributor member there is provided a transversely extending bore 12. Mounted within the bore 12 is a pair of pumping plungers 13 and these are arranged to be moved inwardly as the distributor member rotates, by means of a plurality of cam lobes formed in the internal periphery of an annular cam ring 9, which surrounds the distributor member. The pumping plungers 13 together with the bore 12 define a pumping chamber 14 from which extends a longitudinal passage 15. At its remote end from the pumping chamber the passage 15 communicates with a radially extending delivery port which is arranged to register in turn as the distributor member rotates, with a plurality of outlet ports 16 only one of which is shown. The registration of the delivery port with an outlet port 16 occurs during the time when the pumping plungers 13 are moved inwardly, and during this time fuel is displaced from the pumping chamber to the delivery port. The delivery port 16 communicates by way of a pipeline 17 with an injection nozzle 18 mounted on the engine in such a manner so that it directs fuel to a combustion space of the engine.

The passage 15 also communicates with a plurality of inlet ports 19 which break out onto the periphery of the distributor member. The inlet ports register in turn with an inlet passage 20 formed in the body part 10 and which communicates with a source of liquid fuel under pressure (not shown). For controlling the flow of fuel through the inlet passage 20 there is provided a throttle valve 21 the setting of which can be adjusted by the operator. The arrangement is such that when the delivery port has moved out of register with an outlet 16, an inlet port 19 moves into register with the inlet passage 20 and fuel flows to the pumping chamber 14 to efiect outward movement of the pumping plungers 13.

There is also provided in the body part, a cylinder 22 and mounted within the cylinder is a shuttle 23 this being urged towards one end of the cylinder by resilient means in the form of a coiled compression spring 24. The end of the cylinder accommodating the spring 24 is also provided with an adjustable stop 25 and this end of the cylinder is in communication with a source of fuel at a low pressure. The other end of the cylinder communicates with a passage 26 which is arranged to register with one of the inlet ports 19 at the same time as registration of one of the other inlet ports with the inlet passage 20 takes place. The same end of the cylinder is also in constant communication with a circumferential groove 27 formed in the periphery of the distributor member and this groove communicates with a pair of spill ports 28 which open into the bore 12. The pumping plungers are each provided with a passage 29 whereby at a predetermined position of the pumping plungers during their inward movement, the pumping chamber will be placed in communication with the groove 27.

In operation at the start of the inward movement of the pumping plungers, the passage 26 will be out of register with an inlet port 19 and fuel will flow to an outlet 16. At a predetermined position during the inward movement of the plungers 13, the passages 29 will be brought into register with the ports 28 and when this occurs fuel will flow from the pumping chamber by way of the ports 28 and the circumferential groove 27 to the cylinder 22. The fuel flow will urge the shuttle 23 towards the stop 25. In addition relief of the fuel pressure within the outlet 16 and pipeline 17 will occur and the shuttle will contact the stop 25. The extent of movement of the shuttle 23 can be controlled by the stop 25 and this allows adjustment of the maximum quantity of fuel which can be supplied at each delivery stroke, to the associated engine by varying the residual pressure in the pipe lines 17.

When the delivery port has moved out of register with an outlet 16 and the inlet ports 19 move into register with the

passages

20 and 26 the fuel previously displaced to the cylinder 22 will be returned to the pumping chamber 14 due to the movement of the shuttle 23 under the action of the spring 24.

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

l. A liquid fuel injection pumping apparatus and comprising in combination, a bore, a reciprocable pumping plunger mounted within said bore, said plunger and said bore defining a umping chamber, an outlet from said pumping chamber, said outlet in use, communicating with an injector mounted on an associated engine, a cylinder, a resiliently loaded shuttle mounted in said cylinder, a spill path from said pumping chamber, said spill path communicating with one end of said cylinder, flow of fuel through said spill path occuring at the end of a pumping stroke of the plunger and being controlled by the plunger, the fuel flowing into said cylinder acting to urge the shuttle against the action of its resilient loading and valve means operable to allow the fuel contained in the cylinder to be returned to the pumping chamber during the next filling stroke of the plunger.

2. An apparatus as claimed in claim 1 in which said spill path is in part defined in said plunger and in part by a port which is formed in the wall of said bore, said port communicating with said one end of the cylinder.

3. An apparatus as claimed in claim 2 including a rotary distributor member mounted within a body part and arranged to be driven in timed relationship with the engine with which the apparatus is associated, said cylinder being defined in the body part and the bore being formed in the distributor member, said valve means comprising a second port formed in the body part and in communication with said one end of the cylinder and a third port in the distributor member and which communicates with said pumping chamber.

4. An apparatus as claimed in claim 3 in which a plurality of said third ports is provided and there is provided in the body part a fourth port which is arranged to communicate with a third port when said second port is in communication with a third port, said fourth port communicating with a source of a

Claims

1. A liquid fuel injection pumping apparatus and comprising in combination, a bore, a reciprocable pumping plunger mounted within said bore, said plunger and said bore defining a pumping chamber, an outlet from said pumping chamber, said outlet in use, communicating with an injector mounted on an associated engine, a cylinder, a resiliently loaded shuttle mounted in said cylinder, a spill path from said pumping chamber, said spill path communicating with one end of said cylinder, flow of fuel through said spill path occuring at the end of a pumping stroke of the plunger and being controlled by the plunger, the fuel flowing into said cylinder acting to urge the shuttle against the action of its resilient loading and valve means operable to allow the fuel contained in the cylinder to be returned to the pumping chamber during the next filling stroke of the plunger.

4. An apparatus as claimed in claim 3 in which a plurality of said third ports is provided and there is provided in the body part a fourth port which is arranged to communicate with a third port when said second port is in communication with a third port, said fourth port communicating with a source of fuel under pressure to enable the pumping chamber to be supplied with fuel during the filling strokes of the plunger.

5. An apparatus as claimed in claim 4 including a stop to limit the extent of movement of the shuttle against the action of its resilient loading.