US2062260A - Carburetor - Google Patents

Description

NOV. 24, 1936. w H WEBER 2,062,260

CARBURETOR Filed Dec. 13, 1953 HUI! n INVENTOR m AJmd Patented Nov. 24, 1936 UNITED STATES PATENT OFFICE" Application December 13, 1933, Serial No. 702,103

7' Claims.

My invention relates to new and useful improvements in carburetors, and more particularly to a carburetor for supplying a mixture of air and fuel to an internal combustion engine.

In cold weather operation on starting, the fuel mixture must be exceedingly rich in fuel in order to insure firing of the engine, but as soon as the engine is fired this overrich mixture will result in stalling of the engine, and therefore the ratio of fuel to air must be decreased. It is therefore one object of my invention to provide means operable automatically to reduce the richness of the fuel mixture as soon as the engine has fired and is operating under its own power.

Another object is to provide a carburetor having automatic means responsive to suction and temperature for controlling the ratio of fuel to air at closed throttle position or engineidling speed.

Another object is to provide the throttle valve with the automatic fuel mixture controlling means.

The invention consists in the improved construction and combination of parts, to be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawing, to be taken as a part of this specification, I have fully and clearly illustrated a preferred embodiment of my invention, in which drawing:

Figure l is a view in side elevation and partly in vertical, central section of a carburetor embodying my invention;

Fig. 2 is a detail top plan view of the carbu retor throttle body;

Fig. 3 is an enlarged detail view insection of certain of the structure shown in Fig. 1, and

Fig. 4 is a diagrammatic view showing a fuel supply means embodied in my carburetor.

Referring to the drawing by characters of reference, l designates generally a carburetor comprising a casing having a, mixture passageway 2 therethrough and provided with an air inlet 3 and a mixture outlet 4. The passageway 2 includes a mixing chamber 5 supplied with air from the inlet 3 and with fuel from a main fuel nozzle, not shown, which is supplied from the constant level chamber 6. In the passageway 2, there is a throttle valve 1 of the usual butterfly or disc type, secured on a shaft 8 journaled in the side walls of the casing l and which serves to control the discharge of the fuel mixture from the outlet 4. The passageway 2 is provided with a supplemental fuel inlet 9 discharging into the outlet 4 posterior of the throttle valve 1 and fed with fuel through a conduit l0 supplied from the chamber 6. In the conduit Ill there is a control valve Ill rotatably supported in a valve housing lo rigid with the casing l. The throttle l carries a valve casing II which is preferably screw-threaded, as at I 2, or otherwise rig-,

idly secured in an aperture through the throttle valve. The valve casing II is hollow, being closed at its lower end by an annular member l3 having -a central valve port l4 therethrough establishing communication between the mixing chamber side of the throttle valve and. the interior of the casing II. The member l3 serves also as a valve seat for cooperation with a reciprocable valve disc or member l5 positioned within the casing ll and which seats on the member l3 to close the port M. The valve member I5 is normally held in port closing position and against the member I 3 by a helical coil spring 16 positioned in the valve casing chamber H and held under compression between the member l5 and the upper end wall I! of the valve casing. Through the end wall I! there is a valve port l8 establishing communication between the valve casing chamber 1 I on the passageway 2 on the outlet sideof the throttle-valve so that the ports l4 and I8 together with the chamber ll of the valve casing provide a by-pass passageway from the mixing chamber 5 to the outlet 4 when the throttle valve is substantially in closed or idling position.

The port 3 is controlled by temperature responsivelmeans comprising a valve member l9 carried by one end of a thermostatic element 20,

the throttle valve, as clearly indicated in Fig. 1.

The strip 20 is preferably bent, as'at 22 and 23, so that its free end portion is in spaced, substantially parallel relation to the plane of the throttle valve 1 whereby the movement of the strip in response to temperature change will move the valve member I9 substantially normal to the plane of its valve seat formed by the outlet end of the port H3.

The operation of my carburetor is as follows: When the temperature within the passageway 2 and adjacent the throttle valve is below that at which the liquid fuel will mix efficiently with the air supplied to the passageway 2, the temperature responsivemeans 20 will be spaced from its seat on end wall ll, as shown, so that the port IE will be open. If temperature in the passageway 2 is too low for eflicient mixing of the air and fuel,

some means must be provided to increase the ratio now cranked for starting, with the throttle valve 1 in closed idling position, as shown, and with valve Ill opened, fuel will be fed to the outlet 4 through the conduit IO' from the reservoir 6, which supplemental fuel will be mixed with the small quantity of air passing the circumferential edge of the throttle valve to provide an exceedingly rich fuel mixture for engine starting. The spring 16 exerts sufiicient force against the valve member I5 to hold the Valve member in closed position against the pressure in the mixing chamber 5, tending to force the same to open position. As soon as the engine fires and is operating under its own power, the suction or decrease in pressure in the outlet Q will permit the fluid pressure in the mixing chamber 5 acting through port 14 on valve disc Hi to overcome the spring l6 and move the valve member l5 to open position. When the valve member l5 opens, air will be by-passed through the throttle valve passageway [4, li I8 sufficient to decrease the overrich starting mixture and provide the desired ratio of fuel to air for cold, idling engine operation. Also, as soon as the engine is operating under its own power, the conduit valve Ill will preferably be closed so that the fuel mixture for engine idling operation will be supplied from the mixing chamber 5, the by-pass passageway through the throttle valve serving to provide the necessary increased volume of fuel mixture comprising air from the main inlet 2 and fuel from the main nozzle to prevent stalling of the engine. When the temperature in the passageway 2 adjacent the throttle valve has increased sufficiently to provide for efficient mixing of the air and fuel from the main inlets, the temperature responsive means 20 will move the valve I9 to close the port l8 so that the volume of fuel mixture will be cut down and the engine will be operating at its normal idling speed supplied by the fuel mixture which passes the circumferential edge of the throttle valve. The by-pass passage-- way through the throttle valve will be maintained closed by the valve l9 as long as the predetermined higher temperature is maintained but will act to open the port 18 automatically should the temperature drop sufficiently with the throttle valve in idling position to cause stalling of the engine without the increased quantity of fuel mixture permitted by the by-pass passageway. It will be noted that the bimetal strip 20 serves when the throttle valve is in idling position to throttle the flow through the by-pass passageway so that the quantity of fuel mixture supplied to the engine will vary inversely with a rise in temperature thereby maintaining the quantity of fuel supplied in proportion to the minimum demand of the engine for idling speed in accordance with temperature.

The present invention is shown as embodied in a carburetor such as is disclosed in my copending application S. No. 417,609 filed December 31, 1929, which matured to Patent No. 1,981,483 granted November 24, 1934, to which reference may be had if desired for a more complete description of the carburetor illustrated herein.

What I claim and desire to secure by Letters Patent of the United States is:

1. A carburetor, comprising a casing having a mixture passageway provided with an outlet, a throttle valve in said passageway and controlling said outlet, said valve having a port therethrough, a normally closed pressure responsive valve controlling flow through said port, and temperature responsive means also controlling flow through said port.

2. A carburetor, comprising a casing having a mixture passageway provided with an outlet, a throttle valve in said passageway and controlling said outlet, said valve having a port therethrough, a normally closed pressure responsive valve controlling flow through said port, temperature responsive means also controlling flow through said port, and means to supply fuel to said passageway on the outlet side of said throttle valve.

3. A carburetor, comprising a casing having a mixture passageway provided with an outlet, a throttle valve in said passageway and controlling said outlet, said valve having a port therethrough, a normally closed pressure responsive valve controlling fiow through said port, a spring normally urging said responsive valve to closed position, and temperature responsive means also controlling flow through said port.

4. A carburetor, comprising a casing having a mixture passageway provided with an outlet, a throttle valve in said passageway and controlling said outlet, said valve having a port therethrough, a normally closed pressure responsive valve controlling fiow through said port, a second valve normally open and controlling flow through said port, and thermostatic means operable to move said last-named valve to closed position.

5. A carburetor, comprising a casing having a mixture passageway provided with an outlet, a throttle valve in said passageway and controlling said outlet, said valve having a port therethrough, a valve casing carried by said throttle valve, said throttle valve and said valve casing having a passageway therethrough communicating with said throttle port to permit flow through said mixture passageway when said throttle valve is closed, a valve in said valve casing, a spring in said valve casing normally urging said last-named valve to closed position, a normally open valve controlling flow through said valve casing, and temperature responsive means to close said last-named valve.

6. A carburetor, comprising a casing having a mixture passageway provided with an outlet, a throttle valve in said passageway and controlling said outlet, said throttle valve having a by-pass passageway therethrough, a pressure responsive valve normally closing said by-pass passageway, a bimetallic strip element secured at one end to said throttle valve, and a normally open valve carried by said element and controlling said bypass passageway, said last-named valve being moved to closed position by said element upon predetermined temperature in said casing.

7. A carburetor for supplying a fuel mixture to an internal combustion engine, comprising a casing having a mixture passageway therethrough, a throttle valve controlling the discharge of fuel mixture from said passageway, said throttle valve having a by-pass passageway, a suction operable valve controlling said by-pass passageway, a spring normally acting to hold said by-pass valve closed at engine cranking speeds when said throttle valve is closed but overcome by suction at engine idling speeds to permit opening of said bypass valve, and temperature responsive means operable to close said by-pass passageway when the temperature in said mixture passageway reaches a predetermined degree.

WALTER H. WEBER.

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