US 3254769 A
Description (OCR text may contain errors)
June 7, 1966 w. MOARTHUR 3,254,769
FUEL PUMP FILTER COMBINATION Filed Oct. 16, 1962 y f INVENTOR.
United States Patent 3,254,769 FUEL PUMP FILTER COMBINATION Gerald W. McArthur, Flint, Mich, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware 7 Filed Oct. '16, 1962, Ser. No. 230,879 2 Claims. (Cl. 210194) This invention relates to fuel pumps and filters for internal combustion engines and more particularly to diaphragm pump and filter combination units suitable for use in liquid fuel systems of automotive vehicles.
Heretofore fuel pumps and fuel filters have often been associated in unitary structures insertable in fuel lines leading from fuel tanks to the carburetors of internal combustion engines. A difficulty has risen in such combinations, however, in that excess pressure often would build up in the fuel line between the filter element and the carburetor and cause flooding of the latter.
An object of the present invention is to provide an improved fuel pump and filter combination unit in a fuel system in which the build up of undue fuel pressure adversely affecting a carburetor or the operation of an engine is avoided.
A feature of the present invention is a fuel system in which a diaphragm pump is associated with a fuel filter in a unitary construction involving a single pump body enclosing a valved inlet and a valved outlet, the inlet side of the filter being in communication with the inlet side of the pump by means of a bleed hole. Another feature is a diaphragm pump in which a cover or body portion of the pump provides a bleed hole connection between the inlet side of a fuel filter element and the inlet side of the pump.
These and other important features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims.
In the drawings:
FIGURE 1 is a diagrammatic view of a fuel system for an internal combustion engine, one embodiment of a pump unit of the present invention being utilized in the system;
FIGURE 2 is an enlarged sectional view looking in the direction of the arrows 22 in FIGURE 1 and showing a diaphragm pump and fuel filter combination unit; and
FIGURE 3 is a sectional view of a portion of the structure shown in FIGURE 2 and which is drawn to a much larger scale.
In FIGURE 1, a fuel tank is depicted as a source of liquid fuel for an internal combustion engine partially shown at 12. Conduit means 14 and 16 are illustrated as connecting the tank 10 to a carburetor 18 of the engine 12 by way of a pump and filter combination unit indicated at 20. This unit is adapted to be supported on a portion 22 of the engine 12.
In FIGURES 1 and 2, the pump and filter combination unit 20 is in the form of a diaphragm pump 24 and a filter 26. The pump 24 is adapted to be operated by an engine camshaft 28 through a combination rocker arm arrangement 30 as is customary. By virtue of the action of the camshaft 28 and a coiled spring 32, a pumping diaphragm 34 is adapted to produce a flow of fluid through the pump body portion 36 by way of an inlet 38, an inlet valve 40, a pump displacement chamber 42, an outlet valve 44 and an intermediate outlet 46 leading to the filter 26. The fuel pump 24 is not further described herein as the diaphragm operating parts and oneway valves 40 and 44 are much like those disclosed in the United States Patent No. 2,873,688, granted February 17, 1959, in the name of Gordon B. Elder. The body portion is changed, however, to accommodate the attachment and detachment of the filter 26. The pump body portion 36 is threaded as at 50 for the connection of a cuplike container 52 retaining a filter annulus 54 of suitably porous material. The pump body 36 is formed with a right angle outlet 56 which is connected to the conduit 16 leading to the engine. Coaxial with the body portion 36 the passage 56 extends downwardly through a stub 58. The latter is held in fluid-tight relation with a filter element cover 60 by means of a resilient grommet 62. The element 54 is held in operative position by means of indentations 64 formed in the bottom of the container 52. The pump body portion 36 is apertured as at 66 for the reception of a bleed hole unit 68. This unit is in the form of a small cup with a bleed hole 70 at one end and is tightly fitted into the opening 66 thereby giving communication between the inlet side of the filter element 54 and a chamber 72 of the pump leading to the pump inlet valve 40. A gasket 74 is interposed between one end of the cup 52 and a flange 76 formed on the pump body thereby making a seal-proof joint between the filter and the pump within the combination unit.
It should be noted that, between the pumping diaphragm 34 and the filter container 52, the simple construction disclosed is characterized by the single pump body or housing 36 for accommodating the valves 40 and 44 and the pump inlet and outlet. With this construction, a separate pulsator chamber with its separate diaphragm to even the flow is not needed as the filter element acts as a cushion between the inlet chamber 72 and the right angle outlet passage 56.
Assuming that the engine 12 is operating, the pump 24 will effect a flow of fuel from the tank l0vthrough the line 14 into the chamber 72 of the pump. This fluid will then pass by means of the one-way valves 40 and 44 and by way of the pumping chamber 42 discharge from the valve 44 through an outlet chamber and through the outlet 46 and then to the space surrounding the filter element 54 within the container 52 This fuel will pass through the filter element and then up into the right angle passage 56 into the line 16.
Assuming that the engine has been operated on a hot day and then is stopped, the temperature in the zone immediate to the line 16 may cause tendency of a pressure to arise in the latter and, as a result cause the carburetor 18 to flood. This flooding is prevented, however, by the fact that any undue pressure in the line 16 would be slowly dissipated from the latter by means of the filter element 54 and the bleed hole 70. Any fluid withdrawn from the line 16 to cause the pressure to reduce would pass back through the line 14 into the fuel tank 10.
. 1. A fuel system for an internal combustion engine, said system comprising a source of fuel, an engine, and a combination unit having a pump body and a filter container directly and detachably fixed to said body, said body having an inlet chamber connected to said source, a pump chamber and an intermediate outlet chamber connected to the discharge side of said pump, said pump chamber connected to the inlet chamber and the outlet chamber by means of one-way'valves, said outlet chamber also communicating with said filter container to form a flow path, and a discharge outlet connected to said engine, a passage in said body connecting :said filter container to said body discharge outlet, a permanently open relatively restricted bleed hole in said body connecting said filter container to said body inlet chamber, and a filter element in said filter'container traversing said flow path in the latter leading from said intermediate outlet chamber to said passage.
3 2. A fuel system as set forth in claim 1, said filter element, filter container and one end of said body passage being coaxial, and said filter element being cylindrical with an outlet at one end connected to said body passage.
References Cited by the Examiner UNITED STATES PATENTS 4 2,997,180 8/1961 Loveday. 3,000,467 9/ 1961 Bowers.
3,065,702 11/1962 Dick.
3,082,875 3/1963 Korte 210-416 REUBEN FRIEDMAN, Primary Examiner.
H. L. MARTIN, Examiner.
F. W. MEDLEY, Assistant Examiner.