US3356031A

US3356031A - Liquid fuel pumping apparatus

Info

Publication number: US3356031A
Authority: US
Inventors: Glikin Paul Edgar
Original assignee: CAV Ltd
Current assignee: CAV Ltd
Priority date: 1965-01-07
Filing date: 1966-01-05
Publication date: 1967-12-05
Anticipated expiration: 1984-12-05
Also published as: ES321760A1; FR1462829A; SE304414B

Description

Dec. 5, 1967 GLIK'lN 3,356,031

LIQUID FUEL PUMPING APPARATUS Filed Jan. 5, 1966 United States Patent 3,356,031 LIQUID FUEL PUMPING APPARATUS Paul Edgar Glikin, London, England, assignor to C.A.V.

Limited, London, England 7 Filed Jan. 5, 1966, Ser. No. 518,930 Claims priority, application Great Britain, Jan. 7, 1965, 27,905/ 65 7 Claims. (Cl. 103-2) ABSTRACT OF THE DISCLOSURE This invention relates to a pumping apparatus for supplying fuel to an internal combustion engine and including a pressure pump operating in timed relationship to the engine for supplying fuel under pressure to actuate a pumping shuttle, a storage chamber for receiving fuel to be delivered to the side of the shuttle remote from the pressure pump and a throttle member for controlling said quantity of fuel and also for controlling the quantity of fuel admitted to the pressure pump.

This invention relates to liquid fuel pumping apparatus for supplying fuel to an internal combustion engine and of the kind comprising a body part, a rotary distributor mounted in the body part and adapted to be driven in timed relationship with the engine with which the apparatus is associated, a pressure pump rotor mounted in the body part and rotatable With the distributor, a bore formed in said rotor, a reciprocable plunger in said bore, a cam for imparting inward movement to the plunger as the distributor rotates, a passage in the distributor in communication With said bore, a shuttle movable in said passage, the end of said shuttle remote from the bore serving in part to define the working chamber of an injection pump, a delivery passage extending from said working chamber to the periphery of the distributor, a plurality of angularly spaced delivery ports formed in the body part for registration in turn as the distributor rotates with the delivery passage and means for feeding fuel to the bore and the working chamber during at least part of the time when the delivery passage is out of register with the delivery orts.

p The object of this invention is to provide such a pump in a simple and convenient form.

According to the invention a pump of the kind specified comprises, in combination a cylinder formed in the body part, one end of said cylinder being arranged to communicate with the working chamber during at least part of the time when the delivery passage is out of register with the delivery ports, a metering shuttle slidably mounted in the cylinder, said metering shuttle being arranged to be moved towards said one end of the cylinder to displace fuel into the working chamber during the time when said communication is established, a throttle valve mounted in the body part, said throttle valve being arranged to control the flow of fuel from a sourceof fuel under pressure to the bore whilst said communication is established, the throttle valve also serving to control the flow of fuel by way of the distributor from the source to said one end of the cylinder, to mov'ethe shuttle during at least part of the time when said communication is not established, and the throttle valve being so arranged that as the rate of flow of fuel to the bore is increased the rate of flow of fuel to the said one end of the cylinder will be decreased.

In the accompanying drawings:

FIGURE 1 is a sectional side elevation of one example of a pump in accordance with the invention,

FIGURE 2 is a section on the line 22 of part of the pump shown in FIGURE 1,

FIGURE 3 is a section on the line 33 of part of the pump shown in FIGURE 1,

FIGURE 4 is a section on the line 4-4 of part of the pump shown in FIGURE 1,

FIGURE 5 is a section on the line 55 of part of the pump shown in FIGURE 1, and

FIGURE 6 is a view showing a modification to the 10 pump of FIGURE 1.

Referring to the drawings there is provided a body part 10 in which is mounted a rotary distributor 11 which is adapted to be driven in timed relationship with an engine (not shown) with which the apparatus is to be associated.

At one end of the distributor 11 is mounted a pressure pump rotor 12 whilst at the other end of the distributor is mounted the rotary parts of a vane type feed pump 13. The feed pump has an inlet 14 and an outlet 15 formed in the body part and the inlet in use is connected to a source of fuel. Furthermore, the inlet and outlet are inter connected by an orifice 16 the size of which is de termined by a spring loaded valve member 17, and this combination coupled with the fact that the feed pump supplies an excess of fuel controls the pressure at the outlet 15 in a manner which is dependent upon the speed of rotation of the distributor.

In the rotor 12 is formed a transverse bore 18, which contains a pair of slidable plungers 19 which are arranged through the intermediary of rollers 20 to be moved inwardly as the distributor rotates, by the action of an anmitted movement of the shuttle 23 is determined by a pair of steps 24 mounted beyond opposite ends respectively of the shuttle, and the end of the shuttle 23 remote fro-m the bore 18 defines in part the working chamber of an injection pump. Extending from the working chamber 0 at a position beyond the limit position of the shuttle, is

a radially disposed delivery passage 25 which registers in turn, as the distributor rotates with a plurality of equiangularly spaced delivery ports 26 formed in the body part and which, in use, are arranged to communicate With the cylinders respectively of the associated engine.

Furthermore also extending from a position in the work ing chamber beyond the limit position of the shuttle are a plurality of equi-angularly spaced inlet passages 27, equal in number to the number of delivery ports, and which register, in turn, as the distributor rotates with an inlet port 28 formed in the body part, the communication between the inlet port 28 and an inlet passage 27 being arranged to take place during at least part of the time when the delivery passage. 25 is not in register with a delivery port 26.

The inlet port communicates with the inner end of a cylinder 29 formed in the body part and in which is mounted a reciprocable metering shuttle 30, the outward movement of which is limitedby an adjustable stop 31 which serves, as will be later described as a maximum fuel stop.

Formed in the periphery of the distributor are a first. series of equi-angularly spaced longitudinal grooves 32 equal in number to the number of delivery ports 26 and which communicate in turn with the inlet port 28 as the distributor rotates during part of the time when the inlet port is out of register with an inlet passage 27. This series of grooves 32 in turn establish communication between 0 the inlet port 28 and a port 33 in the body part and which is in communication with a port 34 formed in the wall of a further cylinder 35 in the body part. Furthermore also.

formed in the wall of the cylinder 35 is a second port 36 which is in constant communication with a pressure pump inlet port 37 which opens into the bore in the body part, in which the distributor is mounted. The pressure pump inlet port 37 registers in turn as the distributor rotates, with a plurality of equi-angularly spaced pressure pump inlet passages 38 which communicate with the longitudinal passage 22 at aposition adjacent the transverse bore 18 and beyond the limit position of the shuttle 23. The communication between the pressure pump inlet port and passages is arranged to take place at the same time as the communication between the inlet .port 28 and an inlet passage 27.

The outer end of the cylinder 29 communicates with a port 39 disposed to register in turn with a second series of equi-angularly spaced longitudinal grooves 40 formed in the periphery of the distributor and equal in number to the number of delivery ports. These communicate in turn as the distributor rotates, with a pair of angularly

spaced ports

41, 42 which communicate respectively with the inlet and outlet of the feed pump.

Mounted in the cylinder 35 isa slidable throttle valve 43 which is urged outwardly by the action of fuel pressure from the feed pump outlet acting on its inner end, against the action of a spring 44 the setting of which can be varied by attendant operable means 45. The axial setting of the throttle valve 43 determines the relative sizes of the ports 34 and 36 and these are arranged so that as the throttle valve 43 is moved against the action of the spring the size of the port 34 will be reduced and the size of the port 36 will be increased. Furthermore the ports 34 and 36 are arranged to communicate with the outlet of the feedpump through passages formed in the throttle valve.

The operation of the appartus is as follows, assuming that the cam is about to move the plungers 19 inwardly and that the shuttle 23 is at itslimit position adjacent the transverse bore, in this position the delivery passage 25 will be in register with one of the delivery ports 26 and considering the delivery of the fuel first, as the distributor rotates theplungers will he moved inwardly and the shuttle will be urged by the pressure of fuel developed by the pressure pump, towards its opposite limit position and fuel will be displaced from the working chamber to an engine cylinder. When the trailing edge of the shuttle 23 uncovers a spill passage 46 further movement of the shuttle ceases and any fuel remaining in the pressure pump will be spilledvia the spill passage.

During at least part of the time fuel is being delivered to the engine'a fresh quantity of fuelis being delivered to the inner end of'the cylinder 29and'thisfuel flows via the port 34, the passage-33, one of the series of longitudinal grooves 32 and the inlet port 28. During this time the metering shuttle 30 moves outwardly and fuel is displaced from the outer end of the cylinder *29 through the port 39 and one of the series of longitudinal. grooves 40 tothe port'41. I V

The quantity of fuel admitted to the cylinder 29is determined by the elfective size of the port 34 and if this is sufficiently large the metering shuttle 30 will be moved against the stop 31 so that the maximum quantity of fuel which can enter the innerend of the cylinder is fixed.

As the distributor 'further rotates the pressure pump inlet port 37 communicates with one of the pressure pump inlet passages 38 and the inlet port 28 communicates with one of the inlet passages 27, furthermore, the port 41 communicates with 'one of the series of longitudinal grooves 40 and fuel under pressure is admitted to the outer end of the cylinder 29 causing the metering shuttle to be moved inwardly and displacing the previously measured volume of fuel into the working chamber-"of the injection pump. The admitting of fuel into the working chamber causes the shuttle 23"to be 'moved towardsthe transverse bore and at the same time fuel is admitted through'the port 36 to the'transverse 'bore 18, to'allow the plungers to move outwardly. The-quantity of fuel which enters the transverse bore determines the point at which injection of fuel to the engine begins, since the greater the quantity of fuel which is admitted to the bore the further will the plungers be moved outwardly and the sooner they will be moved inwardly by the cam as the distributor rotates. When the distributor rotates further the cycle as described will be repeated.

As the speed of the engine increases the pressure of fuel delivered by the feed pump will increase and so for a given setting of the spring 44 the throttle member 43 will be moved to reduce the size of the port 34 and so reduce the quantity of fuel which will be delivered to the engine. Thus the throttle valve acts as a hydraulic governor. At the same time as the size of the port 34 is reduced the size of the port 36 is increased and if the variation in the size of the ports is inversely proportional to each other then the point at which delivery of fuel to the engine takes place will be constant. If however the variation of the size of the ports is'not inversely proportional to each other then the point at which delivery of fuel to the engine takes place will vary as the quantity of fuel delivered to the engine varies. Thus by so shaping the ports the timing of delivery can be arranged to occur at the best time depending on the load on the engine.

In some applications it is desirable that the timing be varied with speed and for this purpose and as shown in FIGURE 5, a pressure sensitive valve '47 is mounted in the body part, this valve being arranged to control the size of a by-pass port 48 which communicates with one of the pressure pump passages 38 at the same time -as fuel is being delivered to the transverse bore. Above a predetermined pressure fuel flows through the by-pass port and is added to the quantity passing via the port 36. Thus the timing of delivery of fuel to the engine can be varied in accordance with the speed of the engine. As shown the valve is spring loaded and is responsive tothe pressure of fuel delivered by the feed pump.

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

1. A liquid fuel pumping apparatus forsupplying fuel to an internal combustion engine and comprisingin combination, a body part, a rotary distributor mounted in the body part and adapted to be driven in timed relationship with an engine, a pressure pump rotor rotatable with-the distributor, a bore formed in said rotor, a reciprocable plunger in said bore, cam means for imparting inward movement to the plunger as the rotor rotates, a passage in said distributor in communication with said bore, a shuttle movable in said passage, the end of said shuttle remote from the bore serving in part to define the working chamber of-an injection pump, a-delivery passage extending from said working chamber to the periphery of the distributor, a plurality of angularly spaced delivery ports formed in'the body part and with which the delivery passage re'gisters'in turn as the distributor rotates, a cylinder formed in the body part, one end 'ofsaid cylinder being exposed to the periphery of the distributor, a plurality of angularly spaced inlet passages eXte'nding froms'aid working chamber for communication with said one end of the cylinder in turn during the time when the delivery passage is-out of register with the delivery ports, a metering shuttle 'slidable in said cylinder, means for moving said metering'shuttle towards said "one end of the cylinder whilst an inlet passage is 'in register therewith, thereby to displace'fuel from said one end of the cylinder to said working chamber, an adjustable throttle valve mounted within the body part for controlling the flow of fuel from a source to said one end of the cylinder whilst the inlet passages are out of register therewith and for controlling the flow of fuel to said 'bore during the time when the delivery passage is out of register with the delivery ports. 7

2. An apparatus as claimed in claim 1 including stop means adjustable from the exterior of the apparatus for limiting the permitted movement of said metering shuttle away from said one end of the cylinder.

3. An apparatus as claimed in claim 2 including feed means operable to enable fuel in addition to that supplied by way of the throttle valve to be supplied to the bore.

4. An apparatus as claimed in claim 3 including a feed pump driven by the distributor, valve means for controlling the output pressure of the feed pumps so that the pressure varies in accordance with the speed at which the distributor is driven, and in which said feed means includes an element which is responsive to the output pressure of said feed pump.

5. Apparatus as claimed in claim 4 including a by-pass port through which fuel can flow directly to said bore during the time when the delivery passage is out of register with a delivery port, said element comprising a spring loaded valve member which controls the effective size of said by-pass port.

6. An apparatus as claimed in claim 5 including resilient means acting upon said throttle valve in a direction so as to increase the rate of flow of fuel to said one end of the cylinder, said throttle valve having a surface exposed to the output pressure of the feed pump thereby to cause the throttle valve to move against the action of the resilient means.

7. An apparatus as claimed in claim 6 including an operator adjustable member whereby the force exerted by said resilient means upon the throttle valve can be varied.

References Cited UNITED STATES PATENTS 1,702,649 2/1929 Gentzen 10341 3,035,523 5/1962 Kemp 103-41 3,107,661 10/1963 Kemp 10341 3,263,614 8/1966 Kemp 1032 3,289,590 12/1966 Hutcheon 103-2 3,292,546 12/1966 Evans 10341 DONLEY J. STOCKING, Primary Examiner.

20 W. J. KRAUSS, Assistant Examiner.

Claims

1. A LIQUID FUEL PUMPING APPARATUS FOR SUPPLYING FUEL TO AN INTERNAL COMBUSTION ENGINE AND COMPRISING IN CONBINATION, A BODY PART, A ROTARY DISTRIBUTOR MOUNTED IN THE BODY PART AND ADAPTED TO BE DRIVEN IN TIMED RELATIONSHIP WITH AN ENGINE, A PRESSURE PUMP ROTOR, A RECIPROCABLE DISTRIBUTOR, A BORE FORMED IN SAID ROTOR, A RECIPROCABLE PLUNGER IN SAID BORE, CAM MEANS FOR IMPARTING INWARD MOVEMENT TO THE PLUNGER AS THE ROTOR ROTATES, A PASSAGE IN SAID DISTRIBUTOR IN COMMUNICATION WITH SAID BORE, A SHUTTLE MOVABLE IN SAID PASSAGE, THE END OF SAID SHUTTLE REMOTE FROM THE BORE SERVING IN PART TO DEFINE THE WORKING CHAMBER FOR AN INJECTION PUMP, A DELIVERY PASSAGE EXTENDING FROM SAID WORKING CHAMBER TO THE PERIPHERY OF THE DISTRIBUTOR, A PLURALITY OF ANGULARLY SPACED DELIVERY PORTS FORMED IN THE BODY PART AND WITH WHICH THE DELIVERY PASSAGE REGISTERS IN TURN AS THE DISTRIBUTOR ROTATES, A CYLINDER FORMED IN THE BODY PART, ONE END OF SAID CYLINDER BEING EXPOSED TO THE PERIPHERY OF THE DISTRIBUTOR, A PLURLAITY OF ANGULARLY SPACED INLET PASSAGES EXTENDING FROM SAID WORKING CHAMBER FOR COMMUNICATION WITH SAID ONE END OF THE CYLINDER IN TURN DURING THE TIME WHEN THE DELIVERY PASSAGE IS OUT OF REGISTER WITH THE DELIVERY PORTS, A METERING SHUTTLE SLIDABLE IN SAID CYLINDER, MEANS FOR MOVING SAID METERING SHUTTLE TOWARDS SAID ONE END OF THE CYLINDER WHILST AN INLET PASSAGE IS IN REGISTER THEREWITH, THEREBY TO DISPLACE FUEL FROM SAID ONE END OF THE CYLINDER TO SAID WORKING CHAMBER, AN ADJUSTABLE THROTTLE VALVE MOUNTED WITHIN THE BODY PART FOR CONTROLLING THE FLOW OF FUEL FROM A SOURCE TO SAID ONE END OF THE CYLINDER WHILST THE INLET PASSAGES ARE OUT OF REGISTER THEREWITH AND FOR CONTROLLING THE FLOW OF FUEL TO SAID BORE DURING THE TIME WHEN THE DELIVERY PASSAGE IS OUT OF REGISTER WITH THE DELIVERY PORTS.