US2619915A

US2619915A - Liquid-fuel injection means for prime movers

Info

Publication number: US2619915A
Authority: US
Inventors: Ifield Richard Joseph; Watson Ernest Ansley
Original assignee: Joseph Lucas Ltd
Current assignee: ZF International UK Ltd
Priority date: 1941-10-17
Filing date: 1947-07-10
Publication date: 1952-12-02
Anticipated expiration: 1969-12-02

Description

Dec. 2, 1952 R. J. [FIELD ET AL LIQUID-FUEL INJECTION MEANS FOR PRIME MOVERS Filed July 10, 1947 AP/ V .-h- Q Q a a N m l f z/fl mm 0 -v 4 6 3E A? P u m Patented Dec. 2, 1952 UNITED STATES LIQUID-FUEL INJECTION MEANS FOR PRIME MOVERS Richard Joseph Ifield and Ernest Ansley Watson, Birmingham, England, assignors to Joseph Lucas Limited, Birmingham, England Application July 10, 1947, Serial No. 760,002 In Great Britain October 17, 1941 Section 1, Public Law 690, August 8, 1946 Patent expires October 17, 1961 Claims.

This invention relates to liquid fuel injection systems for prime movers, and of the kind comprising a pump driven by the prime mover and a delivery nozzle or nozzles to which the fuel is supplied by the pump. When .the prime mover is initially set in motion by an electric motor or other external source of power, the speed of rotation is often insufficient to enable an adequate delivery to be obtained from the pump to ensure prompt and efiective starting of the prime mover under its own power. To meet this condition an auxiliary starting pump has already been used, but this is not an entirely satisfactory expedient.

The object of the present invention is to provide improved means for providing an adequate quantity of liquid fuel to the prime mover in the starting operation.

The invention comprises a system having in combination with the pump which normally supplies the fuel to the prime mover, an accumulator which in the starting operation is first charged by the pump, and which subsequently delivers its charge to the nozzle or nozzles, and a valve for controlling the accumulator outlet.

In the accompanying sheet of explanatory drawings:

Figure l is a diagram illustrating a liquid-fuel injection system embodying the invention.

Figure 2 is a sectional elevation of the accumulator employed in the system illustrated in Figure 1.

Figure 3 is a diagram illustrating a modified form of the invention.

Figure 4 is a sectional elevation of a preferred form of the accumulator and valve illustrated in Figure 3.

In carrying the invention into effect as shown in Figures 1, and 2, we employ a hollow cylindrical accumulator a of any suitable capacity. Within this is arranged a piston b which is loaded by an adequate spring or springs as 0, weight or gas under pressure. At one end of the accumulator a is provided an inlet d adapted to be connected to the normal fuel supply pump e driven by the prime mover (not shown), and also an outlet 1 adapted to be connected to the delivery nozzle or nozzles as g. The outlet J is controlled by any convenient valve h which may consist, as shown, of a disc adapted to abut on an annular seating 2' around the outlet and having an operating stem 7' which extends from one side of the disc and passes through a bore in the piston b the end of the stem remote from the disc being provided with a collar is against which one side of the piston can abut for moving the disc away from its seating. In addition .a tension spring m may be arranged as shown in association with the valve h to ensure full opening of the outlet I, one end of this spring being attached to the end of the stem 1' remote from the valve, and the other end of the spring being attached to an anchorage n on the adjacent end of the accumulator a.

When the accumulator a is empty, the valve h is held on its seating i by the piston 73 On setting the pump e in motion the liquid fuel supplied by the pump to the accumulator (1 moves the piston b against the spring or springs 0, weight or other opposing force acting on it. Meanwhile the valve 71- is held closed by the pressure of the liquid. When the piston b reaches or approaches the end of its movement it opens the valve h by acting on the collar 7c, the opening movement of the valve being supplemented by the spring m acting on the stem 7'. The pision 1) now returns under the action of the said opposing force causing the liquid content of the accumulator a to be discharged. At the same time the pump e continues its discharge, and the combined discharges are such as will ensure the ample supply of liquid fuel required by the nozzle or nozzles g to start the prime mover.

The valve h having been opened as above described it will remain open so long as the pump e remains in action. On stopping the prime mover (and hence the pump e) the force acting on the accumulator piston b will cause the latter to re close the valve 72, and thereby put the the accumulator in condition for a repetition of the above described action when the prime mover is again set in motion.

In the modification illustrated in Figure 3 we employ for controlling the flow of liquid fuel from the pump e to the nozzle or nozzles g, a valve h provided on or associated with one end of a spring loaded piston 0 which is slidable within a hollow cylindrical body part p. The latter is adapted at one end to form a seating with which the Valve h can cooperate to close an opening whereby this end of the body part is connected to an inlet pipe q communicating with the accumulator a and pump e, the diameter of the seating being considerably smaller than the diameter of the piston 0. At the other end of the body part p is arranged a connection for a drainage pipe 1" leading to a sump (not shown), and at one side of the body part adjacent to the inlet pipe connection q is arranged a connection for as g. The piston o is provided with a longitudi nal groove or passage t adapted to serve as a bypass between the outlet and drainage pipes s, 1".

When the system illustrated in Figure 3 is at rest, the piston ooccupies its forward position under the action of its spring u. In this position the valve h co-operates with its seating to interrupt communication between the inlet and outlet pipes q, 8. Also the outlet pipe s communicates with the drainage pipe 1' through the piston bypass t, causing the outlet pipe s to be drained to the sump.

On starting up the pump e, the first effect is to charge the accumulator a against the action of its piston b, the latter being loaded by a spring or other convenient means. When a sufiicient pressure is attained the valve h is pushed off its seating sufficiently to allow liquid to flow into the body part 10 containing the valve controlling piston o and thence to the outlet pipe s, the accompanying movement of this piston causing the communication between the outlet and drainage pipes s, r to be interrupted. When the liquid pressure acting on the full area of the front end of the piston 0 becomes sufficient the piston is caused to carry the valve It clear of its seating. An unrestricted communication is thereby established between the inlet and outlet pipes q, s, and the accumulator a is free to discharge.

In a preferred form of the system illustrated in Figure 3, the valve h and its controlling piston o are combined with the accumulator as exemplified in Figure 4. In this example the accumulator a contains a spring loaded piston 12, and has formed in one of its sides a longitudinal passage '2). At one end the passage 1; communil cates with an inlet pipe connection 10 through which liquid fuel from the pump can be admitted to one end of the interior of the accumulator a. The other end of the passage 11 communicates with a drainage pipe connection m, which also communicates with the interior of the accumulator a at the end remote from the inlet pipe connection w. At a position adjacent to the drainage pipe connection a: the passage 11 is formed with a cylindrical enlargement in which the valve-controlling piston o is slidably mounted, and which at the end nearest to the inlet pipe connection w serves as a seating for the valve h. The piston o is separate from and of larger diameter than valve h, and is loaded by a spring it which serves to hold one end of the piston in contact with the valve, the latter being slidably supported in the passage 2; by a guide h of cruciform or other convenient cross section which permits free flow of liquid fuel through the adjacent part of the passage when the valveis open. Ata position near the valve h the enlarged portion of the passage v communicates with an outlet pipe connection y through which liquid fuel can flow to the nozzle or nozzles. When the valve h is closed the outlet pipe connection y is connected by a by-pass formed by a longitudinal groove or grooves t in the piston o to the drainage pipe connection :0, this by-pass being closed when the valve is open.

The invention is not limited to the examples above described as subordinate constructional or mechanical details may be varied to suit different requirements.

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

1. A liquid fuel injection system having in combination a fuel pump, a part formed with a fuel delivery passage, an accumulator arranged to be charged with fuel by said pump when the latter is brought into action, a stationary valve seating arranged between said fuel delivery passage and both said pump and said accumulator, and a valve co-operating with said seating to control flow of fuel to said passage from both said pump and said accumulator, said valve being arranged to be opened automatically in response to the delivery pressure of said pump when said accumulator has been charged, and thereafter to be retained by said pressure in the open position so long as said pump remains in action, so that said delivery passage can be supplied with fuel first by said pump and said accumulator jointly, and then by said pump alone.

2. A liquid fuel injection system having in combination a fuel pump, a part formed with a fuel delivery passage, an accumulator comprising a hollow cylindrical body part arranged to be charged with fuel by said pump when the latter is brought into action, and a loaded piston slidable in said body part, a stationary valve seating arranged between said fuel delivery passage and both said pump and said accumulator, and a valve co-operating with said seating to control fuel flow to said delivery passage from said pump, and also to said delivery passage from said hollow cylindrical body part under the action of said piston, said valve being arranged to be opened automatically in response to the. delivery pressure of said pump when said accumulator has been charged, and thereafter to be retained by said pressure in the open position so long as said pump remains in action, so that said delivery passage can be supplied with fuel first by said pump and said accumulator jointly, and then by said pump alone.

3. A liquid fuel injection system as claimed in claim 2 and having a stem on which said valve is mounted and which passes through said piston, and a collar provided on said stem and actuable by said piston for opening said valve when said accumulator is charged.

4. A liquid fuel injection system as claimed in claim 2 and having a stem on which said valve is mounted and which passes through said piston, a collar provided on said stem and actuable by said piston for opening said valve when said accumulator is charged, and a spring attached to said stem for supplementing the opening movement of said valve.

5 A liquid fuel injection system as claimed in claim 2 and having a spring loaded piston of larger diameter than, and acting on, said valve, and a part having a second passage by which said delivery passage is connectible tosaid pump and said accumulator under the control of said valve.

RICHARD JOSEPH IFIELD. ERNEST ANSLEY WATSON.

REFERENCES CITED The following references are of recor file of this patent: d m the UNITED STATES PATENTS Number Name Date 1,502,739 Munzinger July 29, 1924 2,197,772 Rockwell Apr. 23, 1940 2,426,319 Meitzler May 26,1947

FOREIGN PATENTS Number Country Date 294,096 Great Britain i -192s