US3360003A - Carburetor float valve - Google Patents

Description

Dec. 26, 1967 c. PARKER 3,360,003

` CARBURETOR FLOAT VALVE Filed May 14, 1965 YBY United States Patent O 3,360,003 CARBURETOR FLOAT VALVE Leland C. Parker, deceased, late of Rochester, N.Y., by

Laura H. Parker, executrix, Rochester, N.Y., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed May 14, 1965, Ser. No. 456,006 1 Claim. (Cl. 137-448) ABSTRACT OF THE DISCLOSURE A-triangular valve member operated by a fuel level responsive float ilexes against incoming fuel pressure and the force of a biasing spring to provide increasing areas for fuel flow.

This invention relates to carburetors and more particularly to a flexible float valve for a carburetor fuel bowl. f

Theilow of fuel into the fuel bowl of a carburetor is normally controlled by a valve which is operated by a lloat located within the fuel bowl. The float is adjusted to close the valve when the fuel in the bowl reaches the desired level and to open the valve when the fuel drops below this level. When the valve is arranged to be biased closed `by the pressure of the incoming fuel, the force produced by the weight of the iloat and increased by suitable linkage must be sullicient to open the valve against this pressure.

Present day automotive engines require carburetors which will supply an air fuel mixture at a high rate of flow. This requirement can be met by increasing the size of the fuel bowl and the size of the valve which admits fuel to the bowl. However, in some applications, space limitations or other factors limit the increase in size of the fuel bowl to less than required.

Limitations on the size of the fuel bowl also limit the size of the lloat and linkages which may be used to operate the valve. In some cases the force exerted by the float may be insufficient to open the large area valve needed to satisfy the fuel requirements of the carburetor.

The present invention overcomes this diiliculty -by providing a flexible float valve member which may be opened by a very small opening force applied lby the float and linkage since only a portion of the valve member need be opened to admit fuel.

When a rigid valve member is made large enough to supply the fuel requirements, initial movement of the valve to open position often permits excess fuel to flow to the fuel bowl before the regulating valve is closed. This dilllculty is also overcome since the entire valve member of this invention need not be opened to admit fuel to the fuel bowl but only a portion thereof need be opened to permit a small amount of fuel to ilow into the fuel bowl and thus accurately control the level of the fuel.

One feature of this -invention is that it provides an improved iloat valve for controlling the flow of fuel to the fuel bowl of a carburetor.

Another feature of this invention is that it provides a lloat valve for a carburetor which may be opened by a small opening force and yet permit a high rate of fuel llow.

A further feature of this invention is that it provides a flexible float valve member for a carburetor having gradually increasing areas thereof movable away from gradually increasing areas of a valve seat opening to provide accurately controlled gradually increasing rates of flow.

Yet another feature of this invention is to provide a flexible carburetor fuel Ibowl inlet valve member having a small portion which will easily bend away from the 3,360,003 Patented Dec. 26, 1967 valve seat opening upon application of a small amount of pressure thereto and permit a low rate of fuel llow to the fuel bowl.

These and other features of this invention will be apparent from the following specification and drawings wherein:

FIGURE 1 is a partly broken away elevational view of a carburetor embodying a valve according to this invention;

FIGURE 2 is an enlarged view taken generally along the plane indicated Iby line 2 2 of FIGURE l with parts broken away to show the valve seat; and

FIGURE 3 is an exploded view illustrating the components of the valve arrangement.

A carburetor designated generally 10 includes a body 12 and cover 14. A fuel bowl 16 is formed by a portion of the body and cover and contains a float 18. The lloat is secured to one end of an arm 20 which is pivotally mounted on body 12 by pin 22. The other end of the arm engages one end of a plunger 24, the other end of which is adapted to exert an opening pressure on a flexible valve member designated generally 26 which is part of the carburetor float valve designated generally 28. Pressurized fuel supplied by a fuel pump, not shown, flows through the fuel line 30 to the fuel inlet chamber 32. The fuel in the fuel inlet chamber exerts a closing pressure on the valve member 26 and thus increases the pressure needed to open the valve member. As the fuel level in the fuel bowl drops, the lloat also drops pivoting the arm 20v about the pin 22 and exerting an upward pressure on the valve member 26 through the plunger 24. When the valve opens in response to pressure of the plunger, fuel flows to the fuel bowl to restore the fuel to its original level and raise the float to its original position so that valve 28 may be closed as will be described later.

The lloat valve 28 includes the flexible valve member 26 which is generally triangularly shaped and generally complementary in shape to a valve opening 34 which is defined or bounded by a raised wall 36, the upper surface of which provides a valve seat 38. A generally T-shaped spring 40 has the head thereof overlying a base portion of the valve member 26, with the spring and valve member being secured at 42 adjacent a base wall portion of the wall 36. The shank of the spring 40 biases the valve member 26 to a closed position in engagement with the seat 38. It will be noted that the valve mmeber 26 has the sides thereof spaced slightly inwardly of the side wall portions of wall 36 and the apex thereof provided with a small generally rectangularly shaped tab or portion 44 which overlies the apex of the side Wall portions of wall 36. The shank of the spring 40 engages only a portion of the tab 44. The plunger 24 engages the valve member 26 immediately adjacent the tab 44 thereof.

When the fuel level in the fuel bowl drops, the plunger 24 will bend back the tab 44 and an adjacent small area portion of the valve member 26 to thereby permit fuel to llow into the bowl. lf the fuel level is only slightly below the desired level, a small amount of fuel will restore the fuel to the desired level. Only a small portion of the valve member 26 need be opened to admit this small amount of fuel and restore the desired level without overlllling the bowl. Since the force exerted by the float 18 depends on the fuel level in the bowl, it can be seen that where only a slight amount of fuel is needed to lill the bowl to the desired level, the arm 20 will exert only a slight force and since only a small area portion of the valve portion 26 need be opened this force issullicient. Further, since only a small area portion of the valve member 26 is opened, the llow of fuel into the bowl can be accurately controlled.

The shape of the valve member 26 and the opening 34 provide gradually increasing areas to in turn provide gradually increasing rates of flow to the fuel bowl. Thus, depending on the level of the fuel in the bowl and the relationship of this level to the desired level, the valve member 26 and opening 34 can be opened with respect to each other to provide the desired rate of flow necessary to return the level of the fuel in the bowl to that desired.

It is desirable that the valve member and opening be formed in a triangular shape or other shapes which have gradually increasing areas. This permits the plunger to be located so that it contacts a small area portion of the valve member to open a complementary small area portion of the opening. It is also desirable that the plunger 24 be located so that it will contact the valve member 26 remote from the secured portion thereof. This permits a small area portion of the valve to be opened and results in better regulation of the liquid level in the fuel bowl.

Thus an improved carburetor lloat valve has been provided.

What is claimed is:

An internal combustion engine carburetor having a body defining a fuel bowl chamber, a fuel inlet chamber and an inlet port opening from said inlet chamber to said bowl chamber, a raised wall extending circumferentially about said port on the inlet chamber side thereof to form a valve seat having a generally triangular shape, a flexible valve member overlying said raised wall, said valve member having a shape which generally conforms to the shape of said valve seat and which coacts with said valve seat to control fuel owing from said inlet chamber to said fuel bowl chamber, means securing a base portion of said valve member to said body adjacent a base portion of said valve seat, said valve member having an apex portion opposite said base portion and including a tab portion extending outwardly from said apex portion away from said base portion, a leaf spring member overlying said valve member and secured at one end adjacent the base portion of said valve seat and extending over said tab portion of said valve member, fuel level responsive float means disposed in saidvbowl chamber, a pivotal arm secured at one end to said float means, and a reciprocable plunger operated by said arm for opening said valve member in response to a decrease in fuel level in said bowl chamber, said plunger bearing only against and exerting a force on the apex portion of said valve member for flexing said valve member against the pressure of fuel in said inlet chamber and against the force of said spring member whereby only a small portion of said valve member may be unseated initially to permit fuel to flow at a low rate into said fuel bowl chamber and whereby increasing portions of said valve member may be unseated subsequently to permit fuel to flow from said inlet chamber to said fuel bowl chamber at higher rates of flow.

References Cited UNITED STATES PATENTS 1,699,954 1/1929 Connell et al. 137-527 1,850,850 3/1932 Peterson 251-207 2,216,000 9/1940 Crawford 137-173 2,675,025 4/1954 Wynkoop 137-625.12

WILLIAM F. ODEA, Primary Examiner.

D. R. MATTHEWS, Assistant Examiner.

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