US2752136A - Carburetor control valve - Google Patents

Description

June 26, 1956 D. GARDNER 2,

CARBURETOR CONTROL VALVE Filed Nov. 23, 1955 Da le Gardn e)" IN V EN TOR.

United States Patent CARBURETOR CONTROL VALVE Dale Gardner, Fort Wayne, Ind., assignor to Holley Carburetor Company, Detroit, Mich, a corporation of Michigan Application November 23, 1953, Serial No. 393,704

5 Claims. (Cl. 261-42) The object of this invention is to reduce fuel consumption at part throttle-low loadoperation. The specific object of this invention is to avoid the present practice which is to open and shut a tiny fuel valve which is easily upset by a little dirt. By using air vents and husky valves controlling air flows, a little dirt is unimportant. What is more important as a gain over present practice, the air vent opens automatically whenever the engine stops. Now, it so happens that vapor troubles are most serious when stopping for twenty minutes after a run wide open on a hot day. With this invention the fuel vapor escapes easily and the engine can be restarted without fuss. The drawing illustrates diagrammatically the essential elements of the preferred form of my invention.

In the drawing: is the air entrance.

11 is the fuel entrance.

12 is the venturi in the air entrance.

14 is the fuel nozzle outlet from 11 discharging into 12.

15 is the restricted fuel entrance from a fuel chamber 16in which a float 52 maintains a constant level.

18 is the low speed fuel nozzle discharging from passage 11 through openings 20 and 22 adjacent the upstream lip of the butterfly throttle 24 in a well-known way.

26 is the mixture outlet about the throttle 24.

28 is the mixture outlet below the throttle 24.

30 is the first mixture outlet air pressure passage from below throttle 24 to a cylinder 32. A restriction at 49 in the walls of mixture outlet 28 to passage 30 may be needed.

34 is a compression spring that is a spring located in the cylinder 32 acting against a shoulder 33.

36 is a piston in cylinder 32 pushed down against a stop by 34.

40 is a valve which determines whether the mixture is rich or lean.

42 is an atmospheric passage leading from the atmosphere to the chamber 16 past the valve 40. Means not shown prevent dirt entering at this opening 42.

44 is a second mixture outlet pressure passage leading from just above the throttle 24 when throttle 24 is in its part throttle and idling positions. When the throttle 24 is almost wide open the passage 44 relative to the throttle 24 is shifted to the engine side of throttle 24.

46 is a restriction in a passage 78 between 78 and the chamber 16.

Passages 78 and 44 communicate with fuel chamber 16 through a common passage 48.

Passage 78 communicates with the air entrance 10.

47 is a restriction in passage 44. The size of 47 and 46 determines the suction in 16 which amounts to a few inches of water.

50 is a restriction in the wall of the throat of the venturi 12.

54 is a passage from this restriction in 50 to passage 30.

Above the air entrance 10 there is an air-cleaner-silencer (not shown), but now used 100% on all cars, trucks and busses. This air-cleaner-silencer creates a small suction 2,752,136 Patented June 26, 1956 measured in inches of water. A float 52 and needle 56 control the fuel level in the chamber 16.

An exhaust manifold 58 supplies heat to a hot spot 60 .in an inlet manifold 62 to which the carburetor is bolted.

Operation When the throttle is in the idling position, that is the position in which it is shown, then the inlet manifold suction transmitted through passage 30 closes the valve 40 compressing the spring 34. This is the position for maximum economy.

The pressure in the air entrance 10 and in the mixture outlet passage 44 is from 4" to 7" of water below atmospheric. The moment the throttle 24 moves toward its wide open position, but before reaching that position, the suction through passage 44 increases and raises the suction in float chamber to around 8" to 14" of water. If the engine speed incerases, the valve 40 once more becomes closed due to suction at orifice 50 so that once more something less than atmospheric pressure is imposed on the fuel in the float chamber 16 and once more a lean mixture is available for economical running.

When running with the throttle wide open, at slow engine speeds, as when accelerating the suction in passage 30 decreases and the valve 40 opens and once more a rich mixture is available. With wide open throttle, at maximum speed, the valve 40 is closed and now the venturi suction at opening 50 (restricted) modifies the suction at opening 49 (restricted). This raises the suction above the fuel in the float chamber 16 and reduces the fuel flow slightly as is possible under such circumstances. When the car is stopped after a long run on a hot day heat from the hot spot manifold 58 flowing past the hot spot 60 in the inlet manifold 62 reaches the float chamber 16 and as the valve 40 is then wide open, any vapor pressure in the float chamber 16 escapes and no fuel is pushed up fuel passage 11 from the fuel restriction 15. This is an important feature of my invention.

What I claim is:

1. In a carburetor having an air entrance, a venturi therein, a fuel nozzle discharging therein, a mixture outlet, a throttle valve therein, a constant level fuel supply chamber connected to the fuel nozzle, the improvement in the means for controlling the pressure in the constant level chamber comprising a fuel chamber vent passage leading from the air entrance to the upper portion of said chamber, an air pressure passage from the mixture outlet downstream the throttle, a cylinder connected thereto, a moving wall in said cylinder, a spring therein en gaging said wall, a passage from the atmosphere to the space above the level in the fuel supply chamber controlled by a second valve, the pressure downstream the throttle transmitted through said air pressure passage opposing said spring and tending to close second valve, and in which there is a secondary air pressure passage connected to the mixture outlet upstream of the said throttle when said throttle is closed and partly closed and connected downstream said throttle when said throtfle is moved away from its closed position to near its wide open position, said secondary air passage being connected to the fuel supply chamber to increase the depression therein when the throttle is more than a certain degree open and to be ineffective at other positions of the throttle.

2. A device as set forth in claim 1 in which there is a restriction in said vent passage.

3. A device as set forth in claim 1 in which there is a restriction in said vent passage and a second restriction in said secondary air pressure passage.

4. A device as set forth in claim 1 in which there is a restricted passage from said venturi to said first air pressure passage.

5. A device as set forth in claim 1 in which there is a restriction in said vent passage and a second restriction 2,229,85 1 Hufiord Jan. 28, 1941 in said secondary air pressure passage and a restricted "2,609,188 Brehob Sept. 2, I952 passage from said venturi to said first air pressure passage. 2,675,217 Slason Apr. 13, 1954 V 7 References Citedin "the file of this patent V 658 207 G E PATENTS O 3 1951 V reat ritain ct. UNITED STATES PATENTS 859,473 France a. June 3, 1940 1,948,135 Sands Feb. 20, 1934 2,029,142 Wemhoner Ian. 28, 1936

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