US3196796A

US3196796A - Liquid fuel pumps

Info

Publication number: US3196796A
Application number: US270018A
Authority: US
Inventors: Channing Derek Albert; Kemp Kenneth Albert Walters
Original assignee: CAV Ltd
Current assignee: CAV Ltd
Priority date: 1963-04-02
Filing date: 1963-04-02
Publication date: 1965-07-27
Anticipated expiration: 1982-07-27

Description

July 27, 1965 D. A. CHANNlNG ETAL LIQUID FUEL PUMPS 5 Sheets-Sheet 1 Filed April 2, 1965 y 7, 5 D.IA.CHANNING ETAL 3,196,796

Filed April 2 y 7. 1965 D. A. CHANNING ETAL. 3,196,796

LIQUID FUEL PUMPS 5 Sheets-Sheet 5 Filed April 2, 1963 July 27, 1965 I n; A. CHANNING ETAL 3, ,7

LIQUID FUEL PUMPS Filed April 2, 196a 5 Sheets-Sheet 4 July 27, 1965 Filed April 2, 1963 D. A. CHANNING ETAL LIQUID FUEL PUMPS 5 Sheets-Sheet 5 United States Patent 3,196,796 LEQUID FUEL PUMP Derelr Albert (Ihanning, Shepherds Bush, London, and

Kenneth Albert Walters Kemp, Ealing, London, England, assignors to CAN. Limited, Acton, London, England Filed Apr. 2, 1963, Ser. No. 276,018 3 Claims. (Cl. ll3--2) This invention relates to liquid fuel pumps for internal combustion engines, more particularly compression ignition engines, and of the kind comprising an injection pump including a plunger engaging a bore in which it is arranged to be moved inwardly through an injection stroke by the action of a cam, and in which it is moved outwardly by the pressure of the fuel fed thereto from a feed pump during a filling stroke, in combination with a rotary distributor through which fuel can be fed alternately to the bore, and from the bore to the engine cylinders in turn, in timed relationship to an engine with which the pump is associated.

The object of the invention is to provide such a pump in a convenient form.

According to the invention a pump of the kind specified has in combination a cylinder, a shuttle axially movable in the cylinder, passages in the distributor through which fuel can flow from the feed pump to one end of the cylinder to move the shuttle in one direction to displace fuel from the other end of the cylinder to a source at lower pressure whilst the injection pump is partaking of an injection stroke, and whereby fuel can flow from the feed pump to said other end of the cylinder to move the shuttle to displace fuel from said one end of the cylinder to the bore of the injection pump during the filling stroke, and a means for controlling the amount of fuel flowing to and/ or from said other end of the cylinder.

In the accompanying drawings.

FIGURE 1 is a sectional side elevation of one example of a liquid fuel pump for supplying fuel to a four cylinder internal combustion engine.

FIGURES 2, 3, 4, are sections on the line 2--2, 33, 44 of FIGURE 1 respectively.

FIGURE 5 is a view similar to FIGURE 1 with parts of the pump in another position.

FIGURES 6, 7, 8 are sections on the lines 66, 77, 8-8 of FIGURE 5 respectively.

FIGURE 9 is a sectional side elevation of a modification of the pump shown in FIGURE 1.

FIGURE 10 is a view similar to FIGURE 9 with part of the pump in another position and FIGURES 1-1 and 12 are sections on the lines 11I-1, I2I2 of FIGURE 9 respectively.

Referring to the drawings there is provided a body part 1 which at one end contains a feed pump 2 having an inlet 3 and outlet 4- in the body part.

At the other end of the body part there is provided an injection pump which includes a rotary head 5 having formed in its a transverse bore 6. The bore extends diametrically through the head and contains a pair of reciprocable plungers 7. As the head rotates both plungers are moved inwardly at an appropriate time by the interaction of rollers 7a at their outer ends with a surrounding annual cam 7b.

The rotary parts of the feed and injection pumps are interconnected by a cylindrical distributor 8 and are adapted to be driven as a unit through a coupling 9 by the engine with which the pump is associated. In the distributor S is formed an axial passage 10 which at one end is in communication with the bore 6 and which at its opposite end is in communication with a radial outlet 3,196,796 Patented July 27, 1965 passage 11 formed in the distributor. The outlet passage communicates as the distributor rotates with each in turn of four equi-angularly spaced outlet ports 12 in the body part, the outlet ports being in communication with four injection nozzles (not shown) associated with the four cylinders of the engine respectively.

Within the distributor are four equi-angularly spaced radial inlet passages 13 in communication at their inner ends with the axial passage 10. The outer ends of the inlet passages are arranged to communicate in turn With an inlet port 14 in the body part as the distributor rotates. Also provided in the distributor are a pair of circumferentially extending grooves, 15, 16 each groove communicating respectively with four associated equi-angularly spaced longitudinally extending

grooves

17, 18 formed in the periphery of the distributor. The first circumferential groove 15 is arranged to be in communication at all times with the outlet 4 of the feed pump via a passage 19 within the body part and the longitudinally extending grooves 17 are adapted to register in turn with the aforementioned inlet port 14 as the distributor revolves. The circumferential groove 16 is at all times arranged to be in communication with a port 20 in the body part, and the longitudinally extending grooves 18 are adapted to register alternately and in turn with the passage 19 and the feed pump inlet via

passages

21 and 22, as the distributor rotates.

As an alternative (shown in FIGURE 9) the longitudinally entending grooves 13 may communicate in turn with a space formed around the head of the injection pump through a passage 18b the space being in communication with the feed pump inlet.

Within the body part there is provided a cylinder 23 extending radially relative to the distributor, and having slidably mounted therein a shuttle 24. The inner end of the cylinder is in communication with the aforementioned inlet port 14, and the outer end of the cylinder is in communication with the circumferential groove 16 through a throttle.

The trottle may take the form of a cylindrical valve member 25 engaging the outer end portion of the cylinder, and having formed therein a longitudinal groove 26 with a helical edge. The valve member is angularly movable about its axis either manually or by a governor, and the arrangement is such that its angular setting determines the quantity of fuel which can flow to, and from the cylinder to the port 20 through the groove 26.

Moreover, the axial position of the valve member in the cylinder is determined by an externally adjustable stop 27 which limits the axial movement of the valve member by the pressure of fuel. Since the axial position of the valve member determines the permitted movement of the shuttle the stop 27 provides an adjustable setting of the maximum amount of fuel which can be delivered by the pump.

The operation of the pump will now be described. Assume that the pump is filled with fuel and the injection period is just starting. The plungers 7 are moved inwardly by the interaction of the rollers 7a on the annular cam 7b and fuel is displaced along the axial passage 10 to the outlet passage Ill and thence to one of the four outlet ports 12. At the same time fuel is admitted to the inner end of the cylinder, from the feed pump outlet passage via the circumferential groove 15, one of the longitudinally extending grooves 17 and the inlet port 14-. This fuel forces the shuttle 24 outwards in the cylinder. The fuel displaced from the outer end of the cylinder flows via the groove 26 in the valve member 25 to the circumferential groove 16, along one of the longitudinally extending grooves to the

passage

21, or 22 in the alternative to the space around the head of the injection pump via the passage 181;. When the distributor has moved through a predetermined angle of, for example, 45 the plungers 7 are forced outwardly in the following manner. Fuel from the feed pump outlet 4 flows by way of the passage 19, one of the longitudinally extending grooves 18, the circumferential groove 16 and the groove 26 in the valve member 25 to the outer end of the cylinder 23. The shuttle 24 is moved inwardly and fuel is displaced from the inner end of the cylinder via the inlet port 14, one of the inlet passages 13 and the axial passage to move the plungers outwardly. When the distributor has moved through a further 45 another injection period commences and the cycle is repeated.

It will be appreciated that the action of the groove 26 in the valve member is to limit the displacement of the shuttle and so reduce the outward movement of the plungers. The maximum permissible displacement of the shuttle 24 is limited by its outer end abutting against the inner end of the valve member so that even if the valve member is angularly set to permit maximum flow of the fuel entering and leaving the outer end of the cylinder, the maximum amount of fuel which can be supplied to the engine is controlled by the axial setting of the valve member and hence by the stop.

In the modification shown in FIGURE 9 onwards the fuel flows into the outer end of the cylinder 23 by way of a radial passage 28 in the body part which at its inner end is in communication, at the appropriate time, with one of the longitudinally extending grooves 18 and at its outer end is in communication with the outer end of the cylinder at a position to by-pass the throttle. Thus it is only the fuel displaced from the outer end of the cylinder which is throttled.

If desired and as shown in FIGURES 2, 6, 9, 10 and 11 an excess fuel valve may be provided comprising a valve member 29 arranged, when open, to permit fuel to bypass the shuttle 24 and flow directly from the outer end of the cylinder through one of the passages 13 to the bore 6 in the head to permit the plungers to move out to their maximum extents, as permitted by the cam, so that when they are moved inwardly again as the distributor rotates an excess quantity of fuel will be delivered to the engine.

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

1. Liquid fuel pumping apparatus comprising, in combination a stationary hollow body, a feed pump at one end of the body and having a fuel inlet and a fuel outlet therein, a rotary head at the other end of the body part, said head having formed in it a bore, a reciprocable plunger within the bore, a cam mounted in the body and arranged to move the plunger inwardly as the head rotates, a rotary distributor within the body, said distributor connecting the feed pump and the head, a longitudinal passage within the distributor in communication with the bore in the head, a plurality of equi-angularly spaced inlet passages in the distributor extending outwardly from said longitudiin turn, as the distributor rotates with said inlet port to allow fuel from the outlet of the feed pump to move the shuttle axially away from said one end of the cylinder, a further port in the body in communication with said other end of the cylinder, a second series of equi-angularly spaced longitudinal grooves in the periphery of the distributor in communication at all times with said further port and arranged to be placed in communication alternately, and in turn, with the feed pump outlet and the feed pump inlet to move the shuttle towards said one end of the cylinder during the time when the inlet port is in register with one of the inlet passages so as to displace 7 fuel to the bore in the head, and whereby when the inlet port is in register with one of said first series of grooves fuel from said other end of the cylinder will be displaced to the feed pump inlet, a valve member axially slidable in the other end of said cylinder and angularly movable relative to the body, a helical groove formed on the periphery of said valve member for co-operation with said further port to control the rate at which fuel flows therethrough, said valve member also serving as a stop to control the permitted axial movement of the shuttle.

2. A liquid fuel pump according to claim 1 incorporating a further valve member in the body said valve member being operable to allow fuel from the outlet of the feed pump to be fed directly to the bore in the head during the time when the inlet passages are in register with the inlet port.

3. Liquid fuel pumping apparatus comprising in combination, a stationary hollow body, a liquid fuel injection pump mounted within the hollow body and having a rotary driving member, a rotary distributor mounted in the hollow body and rigid with the driving member of the injection pump, a plurality of outlets formed in the body,

passages in the rotary distributor and hollow body for conveying fuel from the injection pump to each in turn of the outlets, a fuel supply port located within the body said supply port being connectable to a source of fuel 7 under pressure, a cylinder in the hollow body, a shuttle nal passage, an inlet port in the body with which said inlet passages are arranged to communicate, in turn, as the distributor rotates, a delivery passage in the distributor extending outwardly from said longitudinal passage, a plurality of equi-angularly spaced delivery ports in the body and with which the delivery passage is in communication, in turn, as the distributor rotates during the time when the plunger is moved inwardly by the cam, a cylinder within the body, one end of said cylinder being in communication with said inlet port, a shuttle axially movable within the cylinder, a first series of equi-angularly spaced longitudinal grooves in the periphery of the distributor, said first series of grooves being in communication at all times with the outlet of the feed pump and arranged to register,

axially movable in the cylinder, further passages in the distributor for establishing communication between said supply port and one end of said cylinder to move the shuttle in one direction thereby displacing fuel from the other end of said cylinder during the time when the injection jump is delivering fuel to an outlet, and whereby the supply port is placed in communication with said other end of the cylinder to move the shuttle in the other direction to cause fuel to be displaced from one end of said cylinder to the injection pump during the filling period of the latter, an axially adjustable plug mounted in said other end of the cylinder for controlling the permitted excursion of the shuttle said plug being provided with a throttling groove whereby the rate at which fuel flows from the supply port to the cylinder is adjustable to control the quality of liquid fuel delivered through the outlet ports.

References Cited by the Examiner UNITED STATES PATENTS 2,946,292 7/60 Chmielecki 103-2 1 2,989,003 6/61 Evans 103--2.1 3,025,797 3/62 Hutchson 103-21 3,035,523 5/62 Kemp et al. 1032.1 3,058,425 10/62 Evans 103-2.1 3,101,079 8/63 Evans 103-21 3,107,661 10/63 Kemp 123139.1l

MARK NEWMAN, Primary Examiner.

LAURENCE V. EFNER, RICHARD B. WILKINSON,

Examiners.

Claims

1. LIQUID FUEL PUMPING APPARATUS COMPRISING, IN COMBINATION A STATIONARY HOLLOW BODY, A FEED PUMP AT ONE END OF THE BODY AND HAVING A FUEL INLET AND A FUEL OUTLET THEREIN, A ROTARY HEAD AT THE OTHER END OF THE BODY PART, SAID HEAD HAVING FORMED IN IT A BORE, A RECIPROCABLE PLUNGER WITHIN THE BORE, A CAM MOUNTED IN THE BODY AND ARRANGED TO MOVE THE PLUNGER INWARDLY AS THE HEAD ROTATES, A ROTARY DISTRIBUTOR WITHIN THE BODY, SAID DISTRIBUTOR CONNECTING THE FEED PUMP AND THE HEAD, A LONGITUDINAL PASSAGE WITHIN THE DISTRIBUTOR IN COMMUNICATION WITH THE BORE IN THE HEAD, A PLURALITY OF EQUI-ANGULARLY SPACED INLET PASSAGES IN THE DISTRIBUTOR EXTENDING OUTWARDLY FROM SAID LONGITUDINAL PASSAGE, AN INLET PORT IN THE BODY WITH WHICH SAID INLET PASSAGES ARE ARRANGED TO COMMUNICATE, IN TURN, AS THE DISTRUBUTOR ROTATES, A DELIVERY PASSAGE IN THE DISTRIBUTOR EXTENDING OUTWARDLY FROM SAID LONGITUDIBAL PASSAGE, A PLURALITY OF EQUI-ANGULARLY SPACED DELIVERY PORTS IN THE BODY AND WITH WHICH THE DELIVERY PASSAGE IS IN COMMUNICATION, IN TURN, AS THE DISTRIBUTOR ROTATES DURING THE TIME WHEN THE PLUNGERR IS MOVED INWARDLY BY THE CAM, A CYLINDER WITHIN THE BODY, ONE END OF SAID CYLINDER BEING IN COMMUNICATION WITH SAID INLET PORT, A SHUTTLE AXIALLY MOVABLE WITHIN THE CYLINDER, A FIRST SERIES OFF EQUI-ANGULARLY SPACED LONGITUDINAL GROOVES IN THE PERIPHERY OF THE DISTRIBUTOR, SAID FIRST SERIES OF GROOVES BEING IN COMMUNICATION AT ALL TIMES WITH THE OUTLET OF THE FEED PUMP AND ARRANGED TO REGISTER, IN TURN, AS THE DISTRIBUTOR ROTATES WITH SAID INLET PORT TO ALLOW FUEL FROM THE OUTLET OF THE FEED PUMP TO MOVE THE SHUTTLE AXIALLY AWAY FROM SAID ONE END OF THE CYLINDER, A FURTHER PORT IN THE BODY IN COMMUNICATION WITH SAID OTHER END OF THE CYLINDER, A SECOND SERIES OF EQUI-ANGULARLY SPACED LONGITUDINAL GROOVES IN THE PERIPHERY OF THE DISTRIBUTOR IN COMMUNICATION AT ALL TIMES WITH SAID FURTHER PORT AND ARRANGED TO BE PLACED IN COMMUNICATION ALTERNATELY, AND IN TURN, WITH THE FEED PUMP OUTLET AND THE FEED PUMP INLET TO MOVE THE SHUTTLE TOWARDS SAID ONE END OF THE CYLINDER DURING THE TIME WHEN THE INLET PORT IS IN REGISTER WITH ONE OF THE INLET PASSAGES SO AS TO DISPLACE FUEL TO THE BORE IN THE HEAD, AND WHEREBY WHEN THE INLET PORT IS REGISTER WITH ONE OF SAID FIRST SERIES OF GROOVES FUEL FROM SAID OTHER END OF THE CYLINDER WILL BE DISPLACED TO THE FEED PUMP INLET, A VALVE MEMBERS AXIALLY SLIDABLE IN THE OTHER END OF SAID CYLINDER AND ANGULARLY MOVABLE RELATIVE TO THE BODY, A HELICAL GROOVE FORMED ON THE PERIPHERY OF SAID VALVE MEMBER FOR CO-OPERATION WITH SAID FURTHER PORT TO CONTROL THE RATE AT WHICH FUEL FLOWS THERETHROUGH, SAID VALVE MEMBER ALSO SERVING AS A STOP TO CONTROL THE PERMITTED AXIAL MOVEMENT OF THE SHUTTLE.