US3752136A

US3752136A - Liquid fuel injection pumping apparatus

Info

Publication number: US3752136A
Application number: US00160805A
Authority: US
Inventors: I Fenne; B Knight; H Hodge
Original assignee: CAV Ltd
Current assignee: CAV Ltd
Priority date: 1970-07-10
Filing date: 1971-07-08
Publication date: 1973-08-14
Anticipated expiration: 1990-08-14
Also published as: DE2134007A1; FR2099318A5; ES394052A1; JPS5030763B1; GB1347488A

Abstract

A fuel injection pumping apparatus includes an accumulator, a pump for charging the accumulator with fuel under pressure and a differential valve for controlling fuel flow from the accumulator to an orifice. In addition, a control valve is provided to control the application of fuel under pressure to the differential valve, the control valve embodying a valve element which is lifted from its seating to apply fuel to the differential valve, and there is in addition, a piston which upon closure of the control valve, moves to reduce the pressure acting on the differential valve.

Description

United States Patent 1191 Knight, deceased et al. 1

[ LIQUID FUEL INJECTION PUMPING APPARATUS [75] inventors: Basil Edward Knight, deceased, late of Kings Langley, England by Norman Henderson Knight, executor; Harold Redmore Hodge, executor, Eastcote, Pinner; Ivor Fenne, Greenford, both of England [73] Assignee: C. A. V. Limited, Birmingham,

England [22] Filed: July 8, 1971 [21] App]. No.: 160,805

[ Foreign Application Priority'm v y 10, 1970 Great Britain 33,570 70 [52] U.S. Cl. 123/139 AT, 123/139 DP, 123/139 AS [51] Int. Cl. F02!!! 47/02 [58] Field of Search 123/139 R, 139 AK,

123/139 AL, 139 AM, 139 AS, 139 AT; 417/293 [56] References Cited UNITED STATES PATENTS 4/1970 Mansfield 123/139 R 1451 Aug. 14, 1973 2,916,028 12/1959 Mansfield 123/139 AT 3,165,264 1/1965 Staalenberg.... 123/139 AT 2,291,939 8/1942 Amery 123/139 R 2,150,574 3/1939 Amery 123/139 AT 2,191,186 2/1940 Amery 123/139 AT 2,274,315 2/1942 Amery 123/139 AT Primary Examiner-Laurence M. Goodridge Attomey-Holman & Stern [57] ABSTRACT A fuel injection pumping apparatus includes an accumulator, a pump for charging the accumulator with fuel under pressure and a difierential valve for controlling fuel flow from the accumulator to an orifice. In addition, a control valve is provided to control the application of fuel under pressure to the differential valve, the control valve embodying a valve element which is lifted from its seating to apply fuel to the differential valve, and there is in addition, a piston which upon closure of the control valve, moves to reduce the pressure acting on the differential valve.

14 Claims, 3 Drawing Figures PAIENIEU M18 1 4:915

SHEET 1 BF 3 ME 2 INVENTZR ATTORNEYS PAIENIEU ws 1 4 sum 2 or 3 ATTORNEYS PATENIED M181 3. 752. 136

sum 3 OF 3 C) en \8 FIGS.

ATTORNEYS LIQUID FUEL INJECTION PUMPING APPARATUS This invention relates to liquid fuel injection pumping apparatus for supplying fuel to an internal combustion engine and of the kind comprising an accumulator for storing fuel at high pressure, a pump for charging said accumulator and a differential valve for controlling the flow of fuel to an orifice, the orifice being disposed to direct fuel into a combustion space of the engine.

The object of the 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 differential valve includes a valve member which is loaded towards the closed position by fluid under pressure and is opened by fuel under pressure derived from the accumulator, a fuel control valve being provided to control the flow of fuel to the differ ential valve, said fuel control valve including a valve element which is lifted from its seating to permit fuel flow to the differential valve and a piston member disposed downstream of the valve element and which moves after closure of the valve element onto its seating, to lower the pressure downstream of the fuel control valve.

Examples of apparatus in accordance with the invention will now be described with reference to the accompanying drawings.

With reference to FIG. 1 of the drawings there is provided a fuel injector which includes a differential valve for controlling the flow of fuel through an orifice 11. In use, the orifice is disposed to direct fuel into a combustion space of an associated engine. The differential valve includes a valve member 12 one end of which is of conical form and co-operates with a seating to prevent the flow of fuel through the orifice 11 from an annular space which is supplied with fuel under pressure by way of a conduit 13. The valve member is spring loaded into contact with the seating and the narrower end remote from the aforesaid conical end is subjected to fluid under pressure conveniently obtained from an accumulator 14 in which fuel under pressure is stored. The intermediate portion of the valve member 12 is of enlarged diameter and the space which accommodates the spring which urges the valve member into contact with the seating, is maintained at a low pressure.

The accumulator is charged by means of a pump 15 which is connected to the accumulator by way of a nonreturn valve 16 and with a fuel inlet by way of a nonreturn valve 17. The pump 15 is actuated by a cam driven by the associated engine.

In order to control the flow of fuel along the conduit 13 from the accumulator there is provided a fuel control valve generally indicated at 18. The valve includes a valve element in the form of a ball 19 and this is loaded into contact with a seating 20 by means of a coiled compression spring. The downstream side of the seating 20 communicates with the conduit 13 and the arrangement is such that when the valve element 19 is lifted from the seating, fuel under pressure from the accumulator is applied to the valve member 12 which is lifted by the accumulator pressure acting under the valve member and overcoming the spring force and the accumulator pressure acting above the valve member, to permit fuel flow through the orifice 11. When the ball is allowed to seat, the valve member 12 returns to its original position and this movement is facilitated by the movement of a piston member 21 which forms part of the fuel control valve 18. The piston 21 is provided with end projections one of which can contact with the ball 19 and the other of which bears against an actuator piston 22. In addition, the piston 21 is shaped for cooperation with a seating 23 and the relative spacing of the various parts of the control valve are such that the ball 19 seats on the seating 20 before the piston 21 seats on the seat 23 in this manner when the ball 19 seats on the seating 20 continued movement of the piston 21 lowers the pressure within the conduit 13 thereby ensuring rapid closure of the valve member 12.

The actuator piston 22 is operated hydraulically by means of a pump 24 operated in timed relationship with the associated engine. The pump 24 includes a plunger 25 located within a cylinder in the wall of which is formed an inlet 26 communicating with a source of fuel. The plunger 25 is provided with a helical groove 27 which is in communication with the pumping chamber of the pump. During inward movement of the plunger 25 when the head of the plunger covers the port 26 fuel under pressure will be applied to the actuator piston 22 and this in turn will move the piston member 21 and the ball 19, thereby causing operationof the differential valve as described. When the plunger 25 has moved to an extent sufficient to uncover the port 26 to the groove 27 the pressure within the pumping chamber collapses and the parts return to their original position. There is disposed between the pumping chamber and the end of the cylinder containing the actuating piston 22, a pressure unloading valve 28a which is lifted during the pumping stroke of the plunger 25 and which closes on the return stroke thereof but which maintains a predetermined pressure between the pump 25 and the actuator piston 22. In addition a relief valve 28 is provided to ensure that the pressure intermediate the pump 25 and the actuator piston 22 does not exceed a predetermined value.

With reference now to FIG. 2. The apparatus shown therein includes a differential valve 30 for controlling flow of fuel through the orifice 11. The differential valve includes a valve element 31 having one end of reduced diameter and shaped for co-operation with a seating. The other end of the valve member is exposed to a pressure which is lower than that of the accumulator the latter being indicated at 32. The reduced pressure acting on the end of the valve member is obtained by means of a reducing valve 33 which operates in a conventional way and which controls the fuel pressure within the conduit 34. g

The application of fuel under pressure to effect opening of the differential valve is controlled by the fuel control valve 18 but instead of being operated mechanically as in the last arrangement the piston 21 is operated hydraulically by applying fuel under pressure from the accumulator 32. The fuel under pressure is applied by way of the conduit 35 and disposed in this conduit is a rotary valve 36 which is operated in timed relationship with the associated engine. In the position shown in the drawing the rotary valve is set to allow accumulator pressure to be applied to the piston 21 of the fuel control valve so that the ball is lifted from its seating.

Disposed intermediate the fuel control valve and the accumulator is a shuttle 37 and this is contained in a cylinder one end of which is in direct communication with the accumulator and the other end of which is in communication with the upstream side of the fuel control valve. The shuttle is loaded in .one direction by a coiled compression spring 38 and in addition movement of the shuttle effects movement of a spool 39. The spool 39 is provided with a groove 40 intermediate its ends.

in the position shown in the drawing the apparatus is part way through an injection stroke and the shuttle 37 is being moved by the accumulator pressure against the action of the spring 38. During this movement the groove on the spool permits the high pressure from the accumulator to act upon the piston 21 of the fuel control valve so that the latter is lifted and the fuel displaced by the shuttle 37 flows to the orifice 11. At a predetermined point in the movement of the shuttle 37 the groove 40 moves out of register with the conduit 35. When this occurs the high accumulator pressure is removed from the piston 21 of the fuel control valve and is replaced by a pressure which is a proportion of the accumulator pressure. This allows the fuel control valve to close and the piston 21 as in the previous example continues its movement to relieve the pressure downstream of the fuel control valve. When the rotary valve is turned the communication of the conduit 35 with the accumulator 32 is broken and accumulator pressure is applied to the end of the cylinder which contains the spring 38 by way of a non-retum valve 38a. This allows the shuttle 37 to move under the action of the spring 38 into contact with a stop 41. The setting of the stop 41 is controlled by a governor associated with the engine and in this manner the stroke of the shuttle 37 can be accurately controlled.

FIG. 3 shows how the apparatus of FIG. 2 can be modified to provide control of the supply of fuel through more than one orifice 11. The rotary valve 36 of FIG. 2 is replaced'by a sleeve like valve element 45 which is rotated in synchronism with the engine with which the apparatus is associated and each orifice 11 is provided with its own differential valve 30 these in turn being controlled by fuel control valves 18'respectively. The example shown in FIG. 3 illustrates how the stop 41 can be positioned by means of a governor. In the arrangement of FIG. 3 governor weights are provided which move against the action of a governor spring 47, means not shown being provided to control the force exerted by the governor spring.

What is claimed is:

l. A liquid fuel injection pumping apparatus of the kind comprising an accumulator, a pump for charging the accumulator with liquid fuel, an orifice through which liquid fuel can flow to an engine, a differential valve for controlling the flow of fuel from the accumulator through said orifice, the differential valve including a valve member which is loaded towards the closed position by fluid under pressure acting on one end of the valve member, said valve member being opened by fuel under pressure derived from the accumulator and acting on the other end of the valve member, a fuel control valve for controlling the flow'of fuel from the accumulator to the differential valve,said fuel control valve including a valve element which is lifted from its seating to permit fuel flow to the differential valve, a cylinder one end of which is connected to a point intermediate the control valve and the differential valve, a piston member disposed in said cylinder said piston member moving after closure of the valve element onto its seating, to lower the fuel pressure downstream of the fuel control valve.

2. An apparatus as claimed in claim 1 in which said valve element is lifted from its seating by movement of said piston member.

3. An apparatus as claimed in claim 2 in which fluid under pressure is utilised to effect movement of the piston member to lift the valve element from its seat.

4. An apparatus as claimed in claim 3 including an actuator piston for effecting movement of said piston member, and pump means operable in timed relationship with the associated engine for supplying fluid under pressure to effect movement of the actuator piston.

5. An apparatus as claimed in claim 4 in which the time during which said pump means maintain pressure on the actuator piston is adjustable to determine the quantity of fuel supplied by the apparatus.

6. An apparatus as claimed in claim 7 including a releif valve for determining the maximum pressure applied to said actuator piston.

7. An apparatus as claimed in claim 6 in which the fluid under pressure which is applied to the valve member to effect closure of same is derived from the accumulator.

8. An apparatus as claimed in claim 3 in which said piston member. is subjected on its end remote from the valve element, to fuel under pressure derived from the accumulator, the application of fuel under pressure being controlled by a rotary valve operable in timed relationship with the engine.

9. An apparatus as claimed in claim 8 including an additional valve disposed between said rotary valve and the piston, said additional valve serving to reduce the pressure applied to said piston member, after a predetermined quantity of fuel has been supplied thereby to allow said piston member to move to allow the valve element to close onto its seating.

10. An apparatus as claimed in claim 9 in which said additional valve is actuated by a shuttle slidable within a cylinder, said cylinder at one end being in constant communication with the accumulator, and at its other end of the cylinder containing the shuttle, the supply of Y fuel to the other end of the cylinder from the accumulator acting in conjunction with a spring loading the shuttle, acting to return the shuttle and additional valve to the initial position, stop means being provided to deter mine said position.

12. An apparatus as claimed in claim 1 1 in which said stop means is adjustable to determine the quantity of fuel supplied by the apparatus.

13. An apparatus as claimed in claim 12 including a pressurising valve for determining the reduced pressure applied to said piston member when said additional valve operates after said predetermined quantity of fuel has been delivered.

14. An apparatus as claimed in claim 12 in which the setting of said stop means is controlled by governor responsive to the speed of the associated engine.

Claims

1. A liquid fuel injection pumping apparatus of the kind comprising an accumulator, a pump for charging the accumulator with liquid fuel, an orifice through which liquid fuel can flow to an engine, a differential valve for controlling the flow of fuel from the accumulator through said orifice, the differential valve including a valve member which is loaded towards the closed position by fluid under pressure acting on one end of the valve member, said valve member being opened by fuel under pressure derived from the accumulator and acting on the other end of the valve member, a fuel control valve for controlling the flow of fuel from the accumulator to the differential valve, said fuel control valve including a valve element which is lifted from its seating to permit fuel flow to the differential valve, a cylinder one end of which is connected to a point intermediate the control valve and the differential valve, a piston member disposed in said cylinder said piston member moving after closure of the valve element onto its seating, to lower the fuel pressure downstream of the fuel control valve.

8. An apparatus as claimed in claim 3 in which said piston member is subjected on its end remote from the valve element, to fuel under pressure derived from the accumulator, the application of fuel under pressure being controlled by a rotary valve operable in timed relationship with the engine.

10. An apparatus as claimed in claim 9 in which said additional valve is actuated by a shuttle slidable within a cylinder, said cylinder at one end being in constant communication with the accumulator, and at its other end communicating with said fuel control valve, said shuttle displacing fuel from said other end of the cylinder to the orifice during its movement towards said other end of the cylinder, the additional valve being operated at a predetermined position of the shuttle to halt the delivery of fuel.

11. An apparatus as claimed in claim 10 including passage means on the rotary valve and through which fuel from the accumulator can be applied to said other end of the cylinder containing the shuttle, the supply of fuel to the other end of the cylinder from the accumulator acting in conjunction with a spring loading the shuttle, acting to return the shuttle and additional valve to the initial position, stop means being provided to determine said position.

12. An apparatus as claimed in claim 11 in which said stop means is adjustable to determine the quantity of fuel supplied by the apparatus.