US3351020A

US3351020A - Liquid fuel injection pumps for internal combustion engines

Info

Publication number: US3351020A
Application number: US521621A
Authority: US
Inventors: Kemp Kenneth Albert Walters
Original assignee: CAV Ltd
Current assignee: CAV Ltd
Priority date: 1965-01-20
Filing date: 1966-01-19
Publication date: 1967-11-07
Anticipated expiration: 1984-11-07
Also published as: DE1288359B; ES322321A2; GB1124301A

Description

NOW 1967 K. A. w. KEMP 3,351,020

LIQUID FUEL INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES Filed Jan. 19, 1966 United States Patent 6 LIQUID FUEL INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES Kenneth Albert Walters Kemp, London, England, assignor to C.A.V. Limited, London, England Filed Jan. 19, 1966, Bar. No. 521,621 Claims priority, application Great Britain, Jan. 29, 1965, 2,439/65 7 Claims. (Cl. 103-2) ABSTRACT OF THE DISCLOSURE A fuel injection pump of the rotary distributor type and incorporating a pair of pumping plungers and a chamber to receive a portion of the total volume of fuel pumped by the pumping plungers at the start of the pumping stroke. The chamber incorporating a movable piston which is moved to its return position at the end of the injection stroke the displaced fuel being allowed to flow to a drain.

In the specification of my British Patent No. 950,063 there is described and claimed a liquid fuel injection pump comprising a body part, a rotary distributor within the body part, a head at one end of the distributor and rotatable therewith, said head having formed therein a radial bore, a plunger in the bore, an annular cam surrounding the head for actuating the plunger as the head rotates, a longitudinal passage in the distributor in communication with said bore, a plurality of annularly spaced ports in the body part adapted for connection to the cylinders of the engine respectively, a radial passage in the distributor in communication with the longitudinal passage, said radial passage being arranged to communicate with each in turn of said ports as the distributor rotates, and during the time when the plunger is moved inwardly by the cam,

means for supplying fuel from a feed pump to the longitudinal passage in the distributor whilst said radial passage is removed from the ports, a cylinder formed in the body part, a shuttle occupying the cylinder and permitted limited axial movement therein, a plurality of radial passages in the distributor in communication with the longitudinal passage and adapted to communicate in turn with one end of said cylinder as the distributor rotates and during the time when the plunger is moved inwardly by the cam, and means for supplying fuel to the opposite end of the cylinder under the control of a valve responsive to feed pump pressure.

With thistype of pump it is arranged that said one end of the cylinder remains in communication with one of the plurality of radial passages for a short time whilst the plunger is able to move outwardly so that fuel contained in said one end of the cylinder can be discharged back into the longitudinal passage, and in this manner the shuttle is returned to its correct position before the plunger is again moved inwardly by the cam. It will be seen that one end of the cylinder has to remain in communication with each in turn of the plurality of radial passages for an extended period and this leads to difiiculty when the pump is intended to supply fuel to an engine having more than four cylinders.

The object of the present invention is to provide a pump generally of the kind just described in a simple and convenient form.

According to the invention a liquid fuel injection pump for supplying fuel to an internal combustion engine having a plurality of cylinders comprises in combination, a body part, a rotary distributor mounted in the body part and arranged to be driven in timed relationship to an engine with which the pump is associated, a bore formed in the distributor, a plunger slidable in said bore, a first passage formed in the distributor in communication with said bore, a plurality of outwardly extending angularly spaced inlet passages formed in the distributor in communication with said first passage, a fuel inlet port formed in the body part and with which said inlet passages register in turn as the distributor rotates, said inlet port communicating with a source of fuel under pressure so that as an inlet passage communicates therewith fuel will flow to said bore to move the plunger outwardly, an outwardly extending delivery passage formed in the distributor in communication with said first passage, a plurality of angularly spaced outlet ports formed in the body part and with which the delivery passage can register in turn as the distributor rotates and during the time When the inlet port is out of register with an inlet passage, a cam for imparting inward movement to the plunger during the time when the delivery passage is in register with an outlet port, a cylinder formed in the body part, a shuttle slidable in said cylinder, a stop for limiting the movement of the shuttle away from one end of the cylinder, means urging the shuttle towards said one end of the cylinder, a spill port in communication with said one end of the cylinder, said spill port being positioned so that the inlet passages in turn, can register therewith as the distributor rotates and during the time when the plunger is being moved inwardly by the cam, and further ways in the distributor through which the spill port can communicate with a drain during the time when the spill port is not in communication with an inlet passage.

In the accompanying drawings:

FIGURE 1 is a sectional side elevation of one example of a pump in accordance with the invention for supplying fuel to a four cylinder engine;

FIGURE 2 is a section on the line 22 of FIGURE 1; and

FIGURE 3 is a view of part of the pump shown in FIG URE 1 in a modified form.

Referring to the drawings there is provided a body part 10 in which is mounted a rotary distributor 11, the latter being adapted to be driven in timed relationship with the engine. At one end of the distributor are mounted the,

rotary parts of a vane type feed pump 12 having an inlet 13 and an outlet 14 defined in the body part. The inlet is, in use, connected to a source of fuel and is also connected to the outlet through a relief valve 15 which regulates the fuel pressure at the outlet. At the other end of the distributor is formed a transverse, bore 16 in which are mounted a pair of plungers 17 and these are arranged to be moved inwardly, as the distributor rotates, by four equi-angularly spaced cam lobes formed on an annular cam ring 18, rollers 19 being mounted intermediate the cam ring and the plungers respectively. Formed in the distributor is a longitudinal passage 20 which communicates with the transverse bore 16 and which at one point has extending therefrom a delivery passage 21. The latter communicates, in turn, as the distributor rotates and whilst the plungers 17 are being moved inwardly by the cam livery passage 21 is out of register with the outlet ports 22.,

The inlet port is in communication with the outlet 14 of the feed pump and there is provided an adjustable throttle lalve 24a for controlling the quantity of fuel flowing to :he inlet port. The pump so far described operates in a Well known way. Fuel is passed to the transverse bore 16 move the plungers 17 outwardly whilst the inlet port 24 is in register with one of the inlet passages 23 and as the distributor further rotates the plungers are moved inwardly and fuel is discharged from the transverse bore and flows via the delivery passage 21 and one of the outlet ports 22 to a combustion space of the engine.

Further provided in the body part is a cylinder 25 one end of which is in communication with a spill port 26 which is located so as to register, in turn, with the aforesaid inlet passages 23 during the time when the plungers 17 are being moved inwardly. Within the cylinder is a slidable shuttle 27 and this is loaded towards said one end of the cylinder by fuel pressure, derived from the outlet'14 of the feed pump by way of a circumferential groove 28 on the distributor, acting on the remote end of the shuttle. Moreover, an adjustable stop 29 is provided to limit the movement of the shuttle 27 away from said one end of the cylinder.

Formed in the distributor are further ways which take the form of four axially extending grooves 30 which are alternately disposed with the inlet passages 23 and which communicate in turn with the spill port 26 during the time when the inlet port 24 is in communication with an inlet passage 23. Furthermore, during the time when a particular groove 30 is in register with the spill port 26 the groove also communicates with a spill passage 31 formed in the body part, the latter being connected to the inlet of the feed pump.

In use when the plungers 17 are moved inwardly by the cam lobes fuel will flow into said one end of the cylinder 25 and will move the shuttle 27 until the latter contacts the stop 29 whereafter the remaining quantity of fuel displaced from the transverse bore 16 will flow through the delivery passage to one of the outlet ports and from there to a combustion space of the engine. When the distributor further rotates the spill port communicates with one of the axially extending grooves 30 and fuel contained in said one end of the cylinder will be displaced by the shuttle to the inlet of the feed pump thereby allowing the shuttle to assume its initial position ready for the next cycle.

By this means the maximum quantity of fuel which can be delivered to the engine is controlled in an extremely convenient manner, and this quantity can be adjusted by altering the settingof the stop 29. If desired and as shown in FIGURE 3 the shuttle may be loaded towards said one end of the cylinder by resilient means in the form of a coiled spring 32.

In order to control the torque or power output of the engine a valve is provided to control the rate at which fuel can escape through the spill port. By this means the return motion of the shuttle 27 towards said one end of the cylinder 25 is impeded. If the shuttle does not move the maximum extent permitted then when the plungers 17 are next moved inwardly less fuel will be required to move the shuttle to contact the stop 29 with the result that more fuel will be delivered to the engine. The setting of the valve is arranged to be dependent upon the speed of the engine and the valve is arranged so that as the speed of rotation of the engine increases the rate at which fuel can flow through the spill port is decreased.

As shown in FIGURE 1 of the drawings the valve takes the form of a cylindrical valve member 33 which is mounted within a bore disposed so that the spill passage 31 intersects same. The valve member is loaded towards one end of the bore by a coiled compression spring 34 accommodating within a hollow cap 35 secured to the body part. Said one end of the bore is in communication with the outlet 14 of the feed pump so that outlet pressure of the feed pump which varies in accordance with the speed of the engine, acts to move the valve member against the action of the spring. Intermediate its ends the valve member is formed to truncated conical shape and the arrangement is such that as the speed of the engine increases the valve member is moved to restrict the passage 31 so that the rate at which fuel can flow through the spill port 26 is reduced.

For starting purposes when an excess of fuel is required, a manually operable valve which may be located in the spill passage 3-1 or in the passage connecting groove 28 to the said other end of the cylinder 25 of the example shown in FIGURE 1 is provided. The valve is operable from the extension of the pump to prevent the flow of fuel through the passages. The effect of closing the passages is to prevent the shuttle 27 moving outwardly or if it does move outwardly, to prevent it returning and in either case no fuel will be spilled during the inward movement of the plungers so that an excess of fuel will 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 injection pump for supplying fuel to an internal combustion engine having a plurality of cylinders comprises in combination, a body part, a rotary distributor mounted in the body part and arranged to be driven in timed relationship to an engine with which the pump is associated, a bore formed in the distributor, a plunger slidable in said bore, a first passage formed in the distributor in communication with said bore, a plurality of outwardly extending angularly spaced inlet passages formed in the distributor in communication with said first passage, a fuel inlet port formed in the body part and with which said inlet passages register in turn as the distributor rotates, said inlet port communicating with a source of fuel under pressure so that as an inlet passage communicates therewith fuel will flow to said bore to move the plunger outwardly, an outwardly extending delivery passage formed in the distributor in communication with said first passage, a plurality of angularly spaced Outlet ports formed in the body part and with which the delivery passage can register, in turn as the distributor rotates and during the time when the inlet port is out of register with an inlet passage, a cam for imparting inward movement to the plunger during the time when the delivery passage is in register with an outlet port, a cylinder formed in the body part, a shuttle slidable in said cylinder, a stop for limiting the movement of the shuttle away from one end of the cylinder, means urging the shuttle towards said one end of the cylinder, a spill port in communication with said one end of the cylinder, said spill port being positioned so that the inlet passages in turn, can register therewith as the distributor rotates and during the time when the plunger is being moved inwardly by the cam, a valve for controlling the flow of fuel through the spill port, the setting of which is dependent upon the speed at which the distributor is driven, and further ways in the distributor through which the spill port can communicate with a drain during the time when the spill port is not in communication with an inlet passage.

2. A liquid fuel injection pump as claimed in claim 1 in which the shuttle is urged towards said one end of the cylinder by fuel under pressure derived from said source.

3. A liquid fuel pump as claimed in claim 1 includinga spring for urging said shuttle towards said one end of the cylinder.

4. A liquid fuel pump as claimed in claim 1 including means for impeding the return motion of the shuttle towards said one end of the cylinder.

5. A liquid fuel pump as claimed in claim 1, in which the motion of the shuttle away from said one end of the bore can be prevented to enable an excess of fuel to be supplied by the pump.

6. A liquid fuel injection pump as claimed in claim 1 including valve-means for controlling the output pressure of said source so that the pressure varies in accordance with the speed at which the pump is driven, the valve which controls the flow of fuel through the spill port being a pressure responsive valve actuated by the outlet pressure of said source.

7. A liquid fuel injection pump as claimed in claim 6 in which said valve comprises a valve member which is movable Within a bore which intersects a passage through Which fuel flows from said spill port, said valve member being urged by a spring towards one end of said bore and being moved against the action of the spring by the pressure of fuel delivered by said source, said valve member being shaped so as to define a restriction to the flow of fuel through the passage, the restriction imposed being varied as the valve member is moved.

References Cited UNITED STATES PATENTS 10/1962 Evans 103-41 10/1962 Bessiere 103--5 2/1965 Bessiere 10 3-42 7/1965 Kemp 103-2 12/ 1966 Evans 1032 FOREIGN PATENTS 11/ 1964 France.

2/ 1964- Great Britain.

DONLEY J. STOCKING, Primary Examiner. 15 W. J. KRAUSS, Assistant Examiner.

Claims

1. A LIQUID FUEL INJECTION PUMP FOR SUPPLYING FUEL TO AN INTERNAL COMBUSTION HAVING A PLURALITY OF CYLINDERS COMPRISES IN COMBINATION, A BODY PART, A ROTARY DISTRIBUTOR MOUNTED IN THE BODY PART AND ARRANGED TO BE DRIVEN IN TIMED RELATIONSHIP TO AN ENGINE WITH WHICH THE PUMP IS ASSOCIATED, A BORE FORMED IN THE DISTRIBUTOR, A PLUNGER SLIDABLE IN SAID CORE, A FIRST PASSAGE FORMED IN THE DISTRIBUTOR IN COMMUNICATION WITH SAID BORE, A PLURALITY OF OUTWARDLY EXTENDING ANGULARLY SPACED INLET PASSAGES FORMED IN THE DISTRIBUTOR IN COMMUNICATION WITH SAID FIRST PASSAGE, A FUEL INLET PORT FORMED IN THE BODY PART AND WITH WHICH SAID INLET PASSAGES REGISTER IN TURN AS THE DISTRIBUTOR ROTATES, SAID INLET PORT COMMUNICATING WITH A SOURCE OF FUEL UNDER PRESSURE SO THAT AS AN INLET PASSAGE COMMUNICATES THEREWITH FUEL WILL FLOW TO SAID BORE TO MOVE THE PLUNGER OUTWARDLY, AN OUTWARDLY EXTENDING DELIVERY PASSAGE FORMED IN THE DISTRIBUTOR IN COMMUNICATION WITH SAID FIRST PASSAGE, A PLURALITY OF ANGULARLY SPACED OUTLET PORTS FORMED IN THE BODY PART AND WITH WHICH THE DELIVERY PASSAGE CAN REGISTER, IN TURN AS THE DISTRIBUTOR ROTATES AND DURING THE TIME WHEN THE INLET PORT IS OUT OF REGISTER WITH INLET PASSAGE, A CAM FOR IMPARTING INWARD MOVEMENT TO THE PLUNGER DURING THE TIME WHEN THE DELIVERY PASSAGE IS IN REGISTER WITH AN OUTLET PORT, A CYLINDER FORMED IN THE BODY PART, A SHUTTLE SLIDABLE IN SAID CYLINDER, A STOP FOR LIMITING THE MOVEMENT OF THE SHUTTLE AWAY FROM ONE END OF THE CYLINDER, MEANS URGING THE SHUTTLE TOWARDS SAID ONE END OF THE CYLINDER, A SPILL PORT IN COMMUNICATION WITH SAID ONE END OF THE CYLINDER, SAID SPILL PORT BEING POSITIONED SO THAT THE INLET PASSAGES IN TURN, CAN REGISTER THEREWITH AS THE DISTRIBUTOR ROTATES AND DURING THE TIME WHEN THE PLUNGER IS BEING MOVED INWARDLY BY THE CAM, A VALVE FOR CONTROLLING THE FLOW OF FUEL THROUGH THE SPILL PORT, THE SETTING OF WHICH IS DEPENDENT UPON THE SPEED AT WHICH THE DISTRIBUTOR IS DRIVEN, AND FURTHER WAYS IN THE DISTRIBUTOR THROUGH WHICH THE SPILL PORT CAN COMMUNICATED WITH A DRAIN DURING THE TIME WHEN THE SPILL PORT IS NOT COMMUNICATION WITH AN INLET PASSAGE.