US2877933A

US2877933A - Liquid fuel injection pumps

Info

Publication number: US2877933A
Application number: US379024A
Authority: US
Inventors: Downing Eric William
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1952-09-12
Filing date: 1953-09-08
Publication date: 1959-03-17
Anticipated expiration: 1976-03-17

Description

March 17, 1959 r-:.'w. DOWNING 2,877,933

LIQUID FUEL INJECTION PUMPS Filed Sept. 8. 1953 .ZIILU EIUZJOE .ZINDOwnzlzz I g, ,0 40, M

2,877,933 LIQUID FUEL INJECTION PUMPS Eric William Downing, Handsworth Wood, Birmingham, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England Application September 8, 1953, Serial No. 379,024

Claims priority, application Great Britain September 12, 1952 1 Claim. (Cl. 222-250) This invention relates to pumps of the shuttle type for injecting liquid fuel in measured quantities to the cylinders of an internal combustion engine. A conventional construction of such a pump comprises a rotary cylindrical valve having therein an axial bore which contains the freely reciprocable shuttle, and having also inlet and outlet ports. The valve is contained in a cast iron barrel, which latter is inserted tightly in an aluminium body part.

A disadvantage of the above described construction is that due to temperature variations, it is necessary to provide a relatively large clearance between the valve and the barrel with consequent risk of undesirably large liquid leakage between the adjacent surfaces of the valve and barrel.

The object of the present invention is to provide an improved construction whereby the above mentioned disadvantage is obviated.

A pump embodying the invention comprises a valvecontaining barrel which is loosely fitted in the body part, sealing rings for preventing leakage of fuel between the barrel and body part, and radially arranged pipe connectors inserted through the body part into engagement with sockets formed in the barrel.

The accompanying drawing is a longitudinal section of a pump embodying the invention.

Referring to the drawing, the rotary valve a containing the freely-slidable shuttle b and end stops c, d (one of which at is adjustable for limiting the endwise movements of the shuttle) is contained in a cylindrical cast iron barrel e having therein the necessary fluid passages. The body part is made from aluminium, or other metal having a larger temperature-coeflicient of expansion than the barrel. The barrel e is made to fit the body part 7 freely so that the body part can exert no detrimental restraint on temperature-expansion of the barrel. Consequently the valve can be made to fit the barrel more closely than has hitherto been practicable. At one end the barrel e has formed on it a flangeg and between the flange and the adjacent end of the body part 1 is inserted a sealing ring it made from rubber-like or other suitable material. Another sealing ring i accommodated in a circumferential groove in the body part embraces the other end of the barrel. The barrel is clamped in posi tion by a cover piece j which encloses the flange g on the barrel and is secured to the body part by a screwthread connection as shown, or otherwise. The cover also holds the valve against axial movement by abutment against a flange k on the Valve.

In the body part are formed a plurality of radial and screw-threaded holes, these being located in appropriate positions for receiving fuel outlet and (when desired) other pipe connectors as m, and in adjacent positions on the barrel are formed sockets for the reception of the inner ends of the connectors. Each such connector has formed on it a screw-thread for engagement with the associated hole in the body part, and on the inner end of the connector is formed a cylindrical extension which fits closely the associated socket in the barrel. A sealing ring n of rubber-like or other suitable material is mounted in a circumferential groove on the 2,877,933 Patented Mar. 17, 1959 2 said extension and another sealing ring 0 is provided on the connector for sealing its connection with the body part. The fuel inlet connector p in the example shown, engages the body part only and is provided with a single sealing ring q.

By this invention leakage of liquid between the valve a and barrel 2 can be minimised in a simple and satisfactory manner.

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

A liquid fuel injection pump of the kind specified, comprising in combination a body part having therein a cylindrical bore and a fuel inlet leading to the bore at a position intermediate the ends of the latter, a barrel fitted in said bore with suflicient clearance therebetween the prevent said body part from exerting a detrimental restraint on temperature-expansion of said barrel, and formed at positions spaced from each other and from the ends of said barrel with coplanar fuel inlet and outlet ports, the fuel inlet ports in said barrel being in communication with the fuel inlet in said body part, radial pipe connectors inserted through holes in said body part into engagement with sockets formed by the fuel outlet ports in said barrel, sealing rings arranged between the peripheries of said sockets and said pipe connectors, said body part being made from a metal having a larger .temperature-coefiicient of expansion than said barrel, a flange provided on one end of said barrel and bearing against a corresponding end of said body part, a cylindrical valve rotatable within said barrel, and formed with an axial bore and with ports in the same planes as the fuel inlet and outlet ports in said barrel so that rotation of said valve serves to establish and interrupt communication between the ports in said barrel and the parts of the valve bore adjacent the ports in said valve, means closing the ends of the valve bore, a flange provided on the end of said valve adjacent the end flange of said barrel, a cover piece secured to the end of said body part adjacent the end flanges of said barrel and valve, and abutting said flanges to prevent axial movements of said barrel and valve relative to each other and to said body part, a shuttle shorter in length than the axial distance between the ports in said valve, and freely slidable in the part of the valve bore between the ports therein under the pressure of fuel supplied to the valve bore from said fuel inlet, to discharge from said valve bore, through each in turn of the fuel outlet ports in said barrel, and thence through the corresponding pipe connectors, during rotation of said valve, fuel previously admitted to said valve bore from said fuel inlet, the extent of the sliding movement of said shuttle being limited by end stops which are constituted by the means closing the ends of the valve bore, and which are shaped to form abutments for opposite ends of said shuttle without obstructing the ports in said valve, and additional sealing rings arranged between and adjacent the ends of the outer periphery of said barrel and said body part for preventing leakage of fuel through said clearance, one of said additional sealing rings being flanked at opposite sides respectively by the end flange of said barrel and the adjacent end of said body part.

References Cited in the file of this patent UNITED STATES PATENTS 171,390 Knowles Dec. 21, 1875 2,137,384 Browne Nov. 22, 1938 2,410,404 Buchanan Nov. 5, 1946 2,503,827 Langmore Apr. 11, 1950 2,602,671 Eastman July 8, 1952 2,630,825 Stephens Mar. 10, 1953 2,731,175 Downing Jan. 17, 1956