US2020778A - Carburetor control - Google Patents

Description

NOV. 12, A1935. `D GREG@ CARBURETOR CONTROL Filed Sept. 24, 1951 2 f 4 rff/ Patented Nov. l2, 1935 UNITED STATES PATENT oFFic-E CARBURETOR CONTROL David Gregg, Caldwell, N. J., assigner, by mesne assignments, to Eclipse Aviation Corporation,

East Orange, N. J., a corporation of New Jersey pplication September 24, 1931, Serial No. 564,952v 16 Claims. (Cl. 261-39) This invention relates to fuel mixing devices, and more particularly to a means for regulating mixing chamber.

Another object of the invention is to provide a fuel control for a carburetor adapted for use in connection with a supercharger that increases the fuel flow as the supercharger pressure is increased.

Other objects of the invention will appear from the followingb description of a preferred embodipanying drawing, in which the ligure is a vertical cross section of a carburetor or fuel mixing device constructed according to the invention and to which is connected a supercharger.

Referring to the drawing, lil is the supercharger casing enclosing an impeller ii and having an inlet i2 and a discharge opening i3. The supercharger is driven by means preferably is connected to the engine (not shown) M to the carburetor inlet it.

The above described connection of a supercharger with the carburetor is well known but occasions some carburetor problems which are not present when the carburetor takes its air supply at atmospheric pressure. carburetor shoulddeliver a constant weight ratio of air to fuel under all operative conditions.- ordinary carburetor is incapable of doing this, but within the narrow limits usually encountered, no correction is used.

The use of a supercharger increases the pressure range and causes the carburetor to deliver a noticeably incorrect mixture, which is due to the fact that the amount of fuel is governed by the suction at the jet, and as liquid fuel is comparatively inexpansible and the air expands under decreased pressure, the ratio of fuel to air 1ncreases as the pressure decreases.

of shaft l la, which It is obvious that the 'I'he above diiiiculty ir. obviated in the present invention by the inclusion of a pressure responsive or barometric device exposed to the mixing chamber pressure for controlling the fuel orice, which includes anv expansible bellows I7 sealed with a 5 predetermined internal pressure, preferably below 3 for expanding the bellows when the surrounding pressure is decreased.

carburetors adapted for use in superchargers, l0

In the fuel chamber i9 is ordinarily subjected to' Venturi tube 2li.

In the illustrated embodiment, the pressure i'rom 15 the super-charger is conducted to the fuel chamber by tube I 5v at some point above fuel level, which is kept at a constant height by means of iioat 2i acting on the levers 22 to close valve 23 at Athe predetermined level. The bellows I7 is 20 moval oi' the cover 26, held in place by any desired means, such as screws 21. bellows i7 is preferably provided with a threaded 25 extension -29, by which it may be bodily moved with respect to cover 2B for adjustment and thereafter locked in position by nut 3i. The lower or movable end cross-passage 38, but if desired, passage 3'! may be eliminated and bellows l1 be so adjusted whereby controlled opening 36 provides the sole communi# cation between the fuel chamber i9 and jet 32. i 40 In the operation oi the device. assuming that the supercharger is delivering a supply of air to the inlet of the carburetor in the direction o1' the arrows shown in the ligure, the pressure at the mixing chamber 39 is transmitted to the fuel 45 chamber |9'and is impressed on the expansible bellows il. The relative position of valve 34 may f be so adjusted with respect to fuel orifice 36 that at any predetermined pressure, valve 34 closes the 6G orifice and allows all fuel to be delivered through the primary fuel orifice 31. At pressures in excess of the predetermined pressure, valve 34 will be raised by the collapse of bellows il and an increased. amount of fuel supplied to jet 32 to com- 55 derstood that the pensate for the increased weight of air passing through the Venturi tube 20.

An ordinary throttle valve Il has been lillustrated, but the inclusion of the valve does not affect the operation of the control, and the valve may be eliminated if'desired and the regulation of the amount of fuel mixture controlled by any other desired means, such as speed control of the supercharger or by throttling the supercharger inlet I2.

While a preferred embodiment of the invention has been illustrated and described, it 'is unshowing and description are illustrative only and that the `invention is not regarded as limited to the form shown, or otherwise, except by the terms of the following claims.

What is claimed is:

l. In a fuel mixing device, a constant level fuel chamber, a mixing chamber, a fuel jet therein, a supercharger connected to the mixing chamber, means for impressing supercharger pressure on the fuel chamber vat all times, and a barometric device within the fuel chamber and actuated by fuel chamber pressure adapted to control the fuel delivered by the jet.

2. Ina fuel mixing device, a fuel chamber, a

mixing chamber, a fuel jet therein, a supercharger connected to the mixing chamber, means for impressing supercharger pressure onthe fuel chamber at all times, and a sealed expansible member actuated by the fuel chamber pressure adapted to control the fuel delivered by the jet.

3. In a fuel mixing device, a fuel chamber, ,a mixing chamber, a fuel jet therein, a supercharger connected thereto, means for impressing supercharger pressure on the fuel chamber at all times, said chamber having an outlet orifice to the jet, an expansible sealed bellows having one end secured to an interior wall of the` fuel chamber, and means secured to the movable end of the bellows adapted to control the fuel orifice.

4. In a fuel mixing device, a fuel chamber, a mixing chambena fuel jet therein, a supercharger connected thereto, means for impressing supercharger pressure on the fuel chamber at all times, said chamber having an outlet orifice to thel jet, an expansible sealed bellows having one end secured to an interior wall of the fuel chamber, and means secured to the movable end of the bellows adapted to enlarge the fuel orifice as the pressure in the fuel chamber is increased.

5. In a fuel mixing device, a mixing chamber, a fuel jet therein, a fuel chamber having an outlet orice to the jet, a supercharger connected to the mixing chamber, means forming a connection between the mixing chamber and fuel chamber at all times, a sealed expansible bellows WithinV the fuel chamber, said bellows having a stem at one end projecting through the chamber wall for adjustably securing the bellows thereto, and means at the opposite end of the bellows adapted to control the orifice.

6. In a fuel mixing device, a fuel jet, a fuel mixing chamber having a throttle, a constant level fuel chamber, means forming two passageways from the fuel chamber to the jet, a sealed expansiblev member in the fuel chamber adapted to control one of said passageways, and means 'for conveying mixing chamber pressure to the fuel chamber from a point anterior of throttle` to a point above the fuel level.

'7. In a fuel mixing device, a fuel jet, a fuel mixing chamber having a throttle, a constant level fuel chamber, means forming two passageways from the fuel chamber to the iet, a sealed expansible member in the fuel chamber adapted to control one of said passageways, and means for conveying mixing chamber pressure to the fuel chamber from a point anterior of throttle to a point above the fuel level, said expansible mem- 5 ber being wholly within the fuel chamber and supported by one of the chamber walls.

8. In combination with a carburetor for supplying a. fuel mixture to an engine, a supercharger, an auxiliary fuel conduit for the carburetor, a device for controlling the flow of fuel through the auxiliary conduit, said device including an expansible member responsive to the differential between the supercharger pressure and a predetermined absolute pressure, and said device bel5 ing arranged to close the auxiliary conduit when the differential pressure reaches a predetermined value.

9. In combination with a carburetor for supplying a fuel mixture to an engine, a supercharg- 20 er, an auxiliary fuel conduit for the carburetor, a valve for said passage, an expansible device for controlling said valve, said device having interior and exterior surfaces one surface being exposed to the influence of supercharger pressure and the 25 other surfacebeing exposed to the influence of a Vpredetermined absolute pressure.

' to air passage pressure for supplying fuel to the 40 the fuel chamber actuated by the air pressure in the passage anterior of the throttle for increasing the fuel supplied by the jet as the air pressure in the passage is increased, said means including a sealed expansible bel- 5 lows having itsexternal surface exposed to the air passage pressure.

l2. In a fuel mixing device, a fuel jet, a mixing chamber having a throttle therein, a supercharger connected tothe chamber, and movable means 50 actuated by the static pressure between the supercharger and throttle adapted to control the amount of fuel delivered by the jet whereby the weight ratio of air to fuel is kept substantially constant, said means including a resilient expansible member having limited expansive movement and exerting sufficient expansive force to prevent a change in member dimensions until the pressure reaches a predetermined value.

13. In a fuel mixing device, a fuel jet, a mix- 50 ing chamber having a throttle valve therein, a

jet and means supercharger connected to the chamber and a genoma 3 for increasing the fuel new delivered by the iet le. xn e mei mixing device, e coutent level when the supercharger pressure lslncreased. fuel chamber, a mixing chamber, a fuel jet 15. In a fuel mixingr device, a constant level therein for delivering fuel from said` fuel chami fuel chamber, a mixing chamber, a. fuel jet tl'iere-1 ber, a supercliarger connected to thefuel chamber,

in for delivering fuel from said fuel chamber, a means for impressing supercharger pressure on v supercharger connected to the fuel chamber, the fuel chamber at all times. a sealed expansible

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