US3507579A - Liquid fuel pumping apparatus - Google Patents

Description

April 21, 1970 K. A. w. KEMP LIQUID FUEL PUMP APPARATUS Filed May 20 1968 RN 5 lm WW N/M W E T W M K April 21, 1970 Y K. A. w. KEMP 3,507,579

LIQUID FUEL PUMP APPARATUS Filed May 20 1968 2 Sheets-Sheet z INVENTOR ATTORNEY United States Patent 3,507,579 LIQUID FUEL PUMPING APPARATUS Kenneth Albert Walters Kemp, Ealing, London, England, assignor to C.A.V. Limited, London, England Filed May 20, 1968, Ser. No. 730,363 Claims priority, application Great Britain, May 23, 1967, 23,885/ 67 Int. Cl. F02m 39/00; F04b'13/00, N00 US. Cl. 417206 6 Claims ABSTRACT OF THE DISCLOSURE A liquid fuel pumping apparatus including an injection pump to which fuel is supplied during the filling strokes, the apparatus including a pair of cylinders, disposed in side-by-side relationship, a pair of shuttles disposed in the cylinders respectively and a beam positioned to transmit movement between the two shuttles, the arrangement being that during movement of the shuttle of one cylinder due to the admission of fuel under pressure to the other cylinder, fuel from the one cylinder will flow to the injection pump and vice versa.

This invention relates to liquid fuel pumping apparatus for supplying fuel to a multi-cylinder internal combustion engine and of the kind comprising an injection pump adapted to be driven in timed relationship with the engine with which the apparatus is associated, and a rotary distributor located within a bore in a body part for delivering the fuel pumped by the injection pump during successive injection strokes to each in turn of a plurality of outlet ports.

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 pair of cylinders formed in the body part and disposed in parallel side-by-side relationship therein, the inner ends of the cylinders being in communication with a pair of circumferentially spaced ports respectively which open out onto the periphery of the distributor, the outer ends of the cylinders being open to a chamber defined in the body part, a pair of shuttles freely mounted within the cylinders respectively, a pivotal beam mounted in the chamber and with which at positions on the opposite sides of the pivot point thereof, the shuttles co-operate respectively, and means on and in the distributor for conveying fuel under pressure to said ports in turn during successive filling strokes of the injection pump, and for conveying fuel flowing from said ports to the injection pump, the arrangement being that fuel flowing to one of the ports causes the shuttles and beam to be moved so that fuel flows from the other port.

In the accompanying drawings,

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

FIGURE 2 is a section on the line 22 of FIGURE 1.

The liquid fuel pumping apparatus shown in the drawings is for supplying fuel to an eight cylinder compression ignition internal combustion engine. The apparatus comprises a body part 1 in which is defined a bore accommodating a rotary cylindrical distributor 12. The distributor is adapted to be driven in timed relationship with an engine with which the apparatus is associated by means of a drive shaft 11 and at one end of the distributor there is formed a head 6. In the head is formed a transversely extending bore 7 which accommodates a pair of pumping plungers 8. For imparting inward movement to the pumping plungers an annular cam ring 10 surrounds the head, the cam ring having eight equi-angularly spaced ice and inwardly extending cam lobes and the cam lobes act on the plungers through the intermediary of rollers 9.

The transversely extending bore is in communication with a longitudinal passage 13 which is formed in the distributor member and which at one point is in communication with an outwardly extending delivery passage 14. As the distributor rotates, the delivery passage registers in turn with eight outlet ports 15 which are formed in the body part and which in use, are connected to the injection nozzles respectively of the associated engine. The communication between the delivery passage 14-and an outlet port 15 is arranged to occur Whilst the pumping plungers 8 are being moved inwardly by the cam lobes so that fuel contained within the transverse bore 7 is displaced to the appropriate outlet port.

At the remote end of the distributor from the head there is mounted the rotary part of a vane-type feed pump 2 having an outlet 4 in communication with a supply passage 16 formed in the body part and an inlet 3 adapted for connection to a source of liquid fuel. The inlet and outlet of the feed pump and interconnected by a valve 5 which acts to control the output pressure of the feed pump 2 in a manner so that it varies in accordance with the speed at which the distributor is driven.

Also formed in the body part are a pair of cylinders 20, 21 which are disposed in parallel side-by-side relationship and which at their outer ends open into a chamber 22. The inner ends of the cylinders communicate respectively with a pair of ports 23, 24 which open onto the periphery of the distributor, the ports being circumferentially spaced and subtendin g at their mid-points .an angle of 45. Furthermore, mounted within the cylinders are a pair of shuttles 25, 26 respectively which at their outer ends are provided with extensions, extending into the aforesaid chamber. Within the chamber is located a pivotal beam 27 and the extensions of the shuttles co-operate with the beam on the opposite sides respectively of its pivot point. The pivot of the beam is defined by a rounded head 28 formed on the side of the beam remote from the shuttles. The head contacts a cam surface 29 defined on a member 30 which is adjustably mounted within a fluid pressure operable piston 31 slidable within a further cylinder, the axis of which extends at right angles to the axis of rotation of the distributor and the axes of the shuttles. The piston 31 is spring loaded in one direction and is movable in the opposite direction by means of fuel under pressure derived from the supply passage 16. Moreover, in order to locate the beam within the chamber a locating pin having a rounded head is provided and this is engaged within a recess defined in the face of the beam remote from the piston.

Also provided in the body part is a throttle member 17, the setting of which is determined by a speed sensitive governor (not shown) and the throttle acts to control the rate at which fuel can flow from the supply passage 16 to a first circumferential groove 32 formed on the periphery of the distributor and axially displaced from the ports 23, 24. Furthermore, extending from this groove are four axially extending supply grooves 33. These grooves are equi-angularly spaced about the periphery of the distributor and are of such a length that they can register with the aforesaid ports.

Also formed on the periphery of the distributor 12 is a second circumferential groove 34 and this is positioned on the remote side of the ports from the groove 32. Extending from this groove are four equi-angularly spaced and axially extending feed grooves 35 and these are alternatively positioned relative to the supply grooves 33. The circumferential groove 34 is in communication with the longitudinal passage 13 formed in the distributor member by way of a non-return valve 36 which is arranged to per- 6 mit the flow of fuel from the groove 34 to the longitudinal passage 13 but to prevent flow of fuel in the reverse direction.

In use, when the plungers 8 have completed their inward movement and the delivery of fuel through the delivery passage 14 has ceased, upon further rotation of the distributor member the delivery passage is moved out of register with a delivery port and one of the supply grooves 33 moves into register with one of the aforesaid ports (as shown port 23) whilst one of the feed grooves 35 moves into register with the other of said ports. Fuel now flows from the outlet of the feed pump into one of the cylinders and the shuttle therein is moved outwardly. In so doing it bears upon the beam 27 and the shuttle 26 is moved inwardly. Fuel previously contained within the cylinder 21 is displaced through the port 24 and flows by way of the feed groove and the second circumferential groove 34 to the longitudinal passage 13. During this time the one way valve 36 is opened. The quantity of fuel which flows to the longitudinal passage is controlled by the setting of the throttle 17. Fuel flowing to the longitudinal passage 13 causes the pumping plungers 8 to be moved outwardly.

As the distributor rotates the aforesaid ports are moved out of register with the supply and feed grooves and the delivery passage 14 is brought into register with the next outlet port. Inward movement of the pumping plungers is then effected by the appropriate pair of cam lobes and fuel is delivered to the engine. As the distributor further rotates, the port 23 which was previously connected to the supply groove is brought into register with a feed groove 35 and the port 24 is brought into register with a supply groove 33. The shuttles therefore move in the opposite direction and a fresh quantity of fuel flows to the longitudinal passage.

The action of the piston 31 is to vary the maximum permitted stroke of the shuttles 25 and 26 and hence the maximum quantity of fuel which can be pumped by the injection pump per injection stroke, in accordance with the speed at which the apparatus is driven. In the particular arrangement the cam surface on the member 30 which is carried by the piston is shaped to reduce the maximum quantity of fuel which can be supplied as the speed at which the apparatus is driven increases. In order to enable initial adjustment of the apparatus to be carried out the aforesaid member 30 is movable in a direction at right angles to the axis of the piston 31 and an external adjustor 37 is provided to enable this adjustment to be carried out.

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

1. A liquid pumping apparatus for supplying fuel to a multi-cylinder internal combustion engine and of the kind comprising an injection pump adapted to be driven in timed relationship with an engine with which the apparatus is associated, a body part, a plurality of outlet ports formed in the body part, a rotary distributor member located within a bore in the body part and including passage means for delivering the fuel pumped by the injection pump during successive injection strokes to each in turn of the outlet ports, a pair of cylinders formed in the body part and disposed in parallel side by side relationship therein, the plane containing the axes of the cylinders being normal to the axis of rotation of the distributor member, a pair of circumferentially spaced ports formed in the body part and which open out onto the the periphery of the distributor member, said spaced ports communicating respectively with the inner ends of said cylinders, a

chamber defined in the body part and into which open the outer ends of said cylinders, a pair of shuttles freely mounted within the cylinders respectively, a pivotal beam mounted in the chamber and with which at positions on the opposite sides of the pivot point thereof, the shuttles co-operate respectively, a feed pump located in the apparatus for supplying fuel under pressure, supply groove means on the distributor member for conveying fuel under pressure from the feed pump to said ports in turn during successive filling strokes of the injection pump, feed groove means for conveying fuel flowing from the one of said ports which is not receiving fuel from the feed pump, to the injection pump, the arrangement being that fuel flowing to one of the ports causes the shuttle in the associated cylinder to be moved outwardly and to tilt the beam to effect inward movement of the other shuttle so that fuel flows from the other port.

2. An apparatus as claimed in claim 1 including adjustor means for varying the maximum stroke of the shuttles during operation of the apparatus.

3. An apparatus as claimed in claim 2 in which said supply groove means on the distributor member comprises a first circumferential groove on the distributor member, said first circumferential groove being in communication with said feed pump, a series of supply grooves extending from said first circumferential groove for registration in turn with said ports, said feed groove means comprising a second circumferential groove on the distributor member, a series of feed grooves extending from the second circumferential groove and disposed intermediate said supply grooves respectively, said supply and feed grooves being positioned so that when one ofsaid ports is in communication with a feed groove the other port will be in communication with a supply groove and vice versa, and a non-return valve through which the second circumferential groove communicates with the injection pump.

4. An apparatus as claimed in claim 3 in which the feed pump is driven by the distributor member and has an inlet and outlet, the inlet and outlet of said feed pump being interconnected by valve means which acts to control the output pressure of the feed pump so that it varies in accordance with the speed at which the apparatus is driven, said means for varying the stroke of the shuttle comprising a pressure responsive piston subjected to the output pressure of the feed pump.

5. An apparatus as claimed in claim 4 including a cam surface defined on a member carried by said piston said cam surface co-operating with a projection on the beam to define the pivot of the beam.

6. An apparatus as claimed in claim 5 in which said member is adjustably mounted relative to the piston thereby to enable the setting of the pivot of the beam to be varied.

References Cited UNITED STATES PATENTS 3,035,523 5/1962 Kemp et a1. 3,292,546 12/1966 Evans 1032 3,319,616 5/1967 Glikin. 3,433,159 3/1969 Kemp 123139 X 3,43 3,160 3/1969 Kemp.

DONLEY J. STOCKING, Primary Examiner W. J. KRAUSS, Assistant Examiner US. or. x.R. 123 139; 417 24s, 252, 485

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