US1797588A - Fuel-supply structure - Google Patents

Description

AQW. POPE, JR

FUEL SUPPLY STRUCTURE Filed July 21, 1926 By @ww,

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March 24, 1931.

Patented Mar. 24, 1931 UNITED STATES,

ARTHUR W. POPE, JR., OF WAUKESHA, WISCONSIN, ASSIGNOR TO WAUKESHA MOTOR- PATENT OFFICE COMPANY, OF WAUKESHA, WISCONSIN, A. CORPORATION OF WISCONSIN FUEL-SUPPLY STRUCTURE Application filed Ju1y 21, 1926. Serial No. 123,967.

My invention relates to fuel supply structure for fuel supply systems in which the internal combustion engine draws its fuel directly from the fuel tank. In such systems,

compensation must be made for any change in level of the fuel in the main fuel tank as otherwise a richer mixture will be delivered to the engine when the tank is full than when it is empty. The object of the invention is to provide structure and arrangement which will cause the engine to draw its fuel from the tank under a pressure which is substantially always that at the bottom of the tank.

Referring to the drawing, the figure is a cross sectional view of a fuel tank and a carburetor structure in association therewith.

The fuel tank 1 is below the level of the carburetor C. The fuel pipe 2 extends from the bottom of the tank and to the carburetor to discharge fuel into the Venturi tube 3, which is located in the air passageway thru the carburetor. A suction duct 4 extends from the tank above the fuel level therein to the carburetor or to the intake passageway to the engine. As shown, it connects with the carburetor air passageway between the Venturi tube 3 and the throttle valve 5 so that when the throttle valve is open, the duct and consequently the space above the fuel in thetank will be subjected to the engine suction.

An atmosphere vent pipe 6 extends from outside of the tank and downwardly thru the tank to the bottom thereof. A fuel supply opening 7 for the tank is normally closed by a cover plate 8.

In operation, when the engine is started, the suction in the carburetor or in the intake passageway is transmitted to the fuel tank thru the connection 4 and a partial vacuum the tank. The air pressure in .the tank, being then less than that of the atmosphere, the fuel level in the vent pipe'6 will drop and when the artial vacuum becomes equal to the head 0 fuel above the bottom of the vent is created in the space above the fuel level inpipe, all fuel in the vent pipe will have been forced into the main tank by the atmospheric pressure. Any tendency to create a higher vacuum in the fuel tank space will be offset by the air flowing into the space from the vent pipe and thru the fuel in the tank.

The suction in the carburetor is also communicated to the carburetor supply pipe 2 and fuel is drawn up in this pipe to the carburetor, but on account of the balancing vacuum in the tank any tendency to increase the vacuum by the drawing of fuel thru the pipe 2 will be compensated for by the passage" of air into the vacuum space thru the vent pipe 6 and the depth of fuel in the tank will not influence the flow of fuel to the carburetor but the conditions will always be thesame as tho the carburetor were drawing its fuel from a level equal to that at the lower end of the vent pipe 6. The advantage of my improved arrangement is that the action is" very rapid, for after only a few turns of the engine, the level or pressure condition will be adjusted so that the engine will always be served under the same pressure condition. Another advantage of my arrangement is that it is not necessary to have thefuel tank absolutely air tight, the only qualification being that the passage between the top of the tank and the carburetor or intake passageway be large enough to draw off more air thru it than can leak into the tank. Still another advantage is due to the fact that the vacuum above the fuel will not be influenced by the formation of fuel vapors caused by heatin the fuel as all such vapors will be drawn 0 as they are should be of sufficient dimension to insure the creation of a sufiicient vacuum effect in the fuel tank for efficient balancing purposes, care should be taken not to have the passage too large in order to prevent excessive amounts of air being drawn thru the fuel in the tank which would tend to upset carburetion and also to draw off large quantities of fuel vapors. The passage 4 has a restricted portion X which acts to damp the influence of the manifold pulsations between the suction strokes of the engine. This assures maintenance of the proper degree of vacuum above the fuel when the throttle 5 is open, either partially or completely, so that the effective fuel level in the tank remains constant and is not affected by the pulsations between the engine strokes due to the inertia of the fuel and the throttling action of the restriction. This restriction X also prevents the flow of an excessively large volume of air through the fuel supply with the resulting removal therefrom of light ends.

I have shown an air vent or bleed 10 into the fuel supply pipe 2 which vent is adjustable by means of a valve 11.

Having described my invention, I claim as follows:

1. In combination with an internal combustion engine and a carburetor therefor, a fuel tank, the actual fuel level in said tank being lowered by and in accordance with withdrawal of fuel therefrom, and means for maintaining a substantially constant effective fuel level in the tank, said means comprising a carburetor fuel supply tube extending from a point adjacent the bottom of the tank, a vent tube having its lower end opening into the tank adjacent the bottom thereof and its upper end open to the atmosphere above the actual fuel level, and a suction tube opening into the tank above the actual fuel level and communicating with the fuel intake passageway of the engine.

2. In combination with an internal combustion engine and a carburetor therefor, a fuel tank, the actual fuel level in said tank being lowered by and in accordance with withdrawal of fuel therefrom, and means for maintaining a substantially constant effective fuel level in the tank, said means comprising a carburetor fuel supply tube extending from a point adjacent the bottom of the tank, an air inlet tube opening into the tank adjacent the bottom thereof. and means independent of said fuel supply tube establishing communication between the space in the tank above the fuel and the intake of the engine. whereby apartial vacuum is created and maintained: above the fuel by the direct action of the engine suction.

3. In combination with an internal combustion engine and a carburetor therefor, a fuel tank,.and means for compensating for lowering in the actual fuel level in the tank and for maintaining a substantially constant effective fuel level therein, said means comprising a carburetor fuel supply tube extending from a point adjacent the bottom of the tank, an air inlet tube opening into the tank adjacent the bottom thereof, and a direct connection between the space in the tank above the actual fuel level therein and the intake passage of the engine.

4. In combination with an internal combustion engine and a carburetor therefor, a fuel tank, a carburetor fuel supply tube extending from a point adjacent the bottom of the tank, said tank being below the portion of said tube within the carburetor, an air admission tube opening into the tank adjacent the bottom thereof, and a suction tube comcunicating with the tank above the fuel therein and with the fuel intake passage to the engine.

5. In combination with an internal combustion engine and a carburetor therefor, a fuel tank, the actual fuel level in said tank being loweredby and in accordance with withdrawal of fuel therefrom, a carburetor fuel supply tube opening into the tank adjacent the bottom thereof, means for withdrawing the gases and vapors from the tank above the fuel and for maintaining a partial vacuum therein during operation of the engine, and an air admission tube opening into the tank adjacent the bottom thereof.

6. In combination with an internal combustion engine and a carburetor therefor, a fuel tank, the actual fuel level in said tank being lowered by and in accordance with withdrawal of fuel therefrom, a carburetor fuel supply tube opening into the tank adjacent the bottom thereof, means for withdrawing the gases and vapors from the tank above the fuel and for maintaining a partial vacuum therein during operation of the en gine, said means acting to supply the withdrawn gases and vapors to the engine for consumption therein, and an air admission tube opening into the tank adjacent the bottom thereof.

7 A method of supplying fuel to an internal combustion engine from a source of supply of fuel having a variable actual level, consisting in withdrawing fuel from said source of supply and supplying the withdrawn fuel to the engine, creating and maintaining a partial vacuum above the body of fuel constituting the source of supply by the suction effect of the engine, and admitting air to the space above the body of fuel when the value of the partial vacuum created exceeds the value of the head of said fuel body.

8. A method of supplying fuel to an internal combustion engine from a source of supply of fuel having a variable actual level, consisting in withdrawing fuel from said source of supply and supplying the Withdrawn fuel to the engine, withdrawing the gases and vapors from above the body of fuel constituting the source of supply and maintaining a partial vacuum above said bod and admitting air to the space above the b0 y of fuel when the value of the partial vacuum created exceeds the value of the head of said fuel body.

In witness whereof, I hereunto subscribe my name this 15th day of July, 1926.

ARTHUR W. POPE, J R.

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