US2293792A - Carburetor - Google Patents

Description

Au 25, 1942. LL 2,293,192

CARBURETOR 1 Fi led Nov. 9, 1940 ATTORNEYa Patented Aug. 25, 1942 Thomas M. Ball, Detroit, Mich., assignor to Ball & Ball Carburetor Company, Detroit, Mich, a I

partnership Application November 9, 1940, SerialNo. 365-,00'0

2 Claims.

The present invention relates to carburetion devices for internal combustion engines and comprises means for injecting an auxiliary quantity of fuel into the carburetor when acceleration is desired. Specifically, the invention comprises meansfor injecting a quantity of fuel into the throat of the carburetor-"in addition to that-normally supplied when the throttle-valve is opened, and controlling the quantity of fuel so injected in accordance with the temperature of the engine 'withwhich the carburetor is associated in such manner as to reduce the amount of auxiliary fuel in proportion to the degrees of temperature adjacent the carburetor. It is the primary object of the present invention to enrich the mixture during acceleration of the engine to'a greater extent when the engine is cold than when the engine is warm.

A further object of the present invention is to providesimple means for controlling the operation of an accelerator fuel pump associated with a carburetor in accordance with the temperature of the engine and of the air surrounding the carburetor. A further object of the present invention is to provide an auxiliary fuel supply means for augmenting the normal fuel supply-to a carburetor when the throttle valve is opened, which auxiliary fuel supply means may be automatically controlled to supply varying amounts of fuel in accordance with the temperature of the engine, such amounts being greater whenthe engine is cold and decreasing asthe engine becomes warm until the auxiliary fuelsupply is discontinued or reaches a predetermined minimum.

Anadditional object of the invention is the "provision of a temperature responsive member in a device of this kind which serves as the effectivesource of fuel displacing energy.

These and other objects of the invention may be. more readily understood from a study of the following'specification taken in connection with the accompanying drawing wherein like numerals refer to like parts throughout.

In the drawing,

Fig. 1 is a side view in elevation of a carburetor having the present invention applied thereto and with parts broken away for better understanding of the invention.

"Fig. 2 is a vertical section taken substantially' centrally of Fig. 1 along line 2-2 and looking in the direction of the arrows.

Fig. 3 is a view in elevation of the carburetor taken from the left side of Fig. 1 and with certain parts broken away.

an outlet 22 leadingto an: auxiliary fuel jet 23 with the auxiliary charge .or fuel Fig.4 is a top plan view of the carburetor having the-present invention applied thereto.

The invention is shown applied to a standard type of carburetor comprising anintake throat 10- and throttle valve II- by means of which the normal supplyof fuel to the engine is induced to flowthroughfthe-main fuel ports I2 or the idle port [3 in accordance with known principles of carbureti'on. The carburetor isalso supplied with a choke valve M which maybe manually or automatically controlled in accordance with usual practice, anda constant level chamber l5 having -a float valve: including the ball float l6 therein from'whichfuel is led to the main fuel ports I2 and idle port'l3 through passages which are not fully shown in this application.

The presentinvention is concerned with an auxiliary-fuel supply means including a fuel injection device comprising the cylinder I! in which piston IBoperates. The bottom of-the cylinder -l"| is connected tothe constant level chamber [5 through an inlet l9 having'a ball check device therein. The ball checkdevice 20 is situated in an enlarged portion of the inlet I9 and is retained therein bya spring clip retaining ring a 2 I, the "enlargement being of :suflicient, diameter 'topermit the ball-to admit fuel when the piston 18 is raised in the cylinder l1. When the piston 18- is lowered, the ball checkZll closes the inlet l9 and fuel is forced from the cylinder l'l through situated in an air passage and so located-as to projectfuel through anauxiliary port 2610- oated in the throat I0 adjacentthenormal fuel supply ports l2. When the throttlevalve II is openedQair may' be drawnth'rough the passage 25 by "the suction of the engineland' thence through the auxiliary port 26 in which it 'is mixed projected through the injector nozzle '23.

The throttle valve H ismounted upon a shaft 30 having one end fixed to an operating lever 3| by :means of which the throttle valve may be manually opened or closed to varying extents.

'I'he opposite'end of shaft 30, projecting from the carburetor at the 'other side thereof,.'carries a substantially triangular plate 32, to thelower corner of which isattached one endof a tension spring 33 having its opposite end fastened to a fixed pin 34, the-spring '33 being so arranged as to tend always to close the throttle valve l l until manually opened. The other free corner of the triangular plate 32 is provided with a series of holes 35 at different angular positions with respect to the throttle valve II, in a selected one fications.

of which is fixed one end of a link 36 extending to the lower end of a pushrod 31 guided for vertical sliding movement in a slot 38 through a portion of the carburetor housing. The upper end of the pushrod 31 is bent laterally and outwardly to a position directly over the upper end of the clinder l1 and is provided with an opening through which is slidably guided the plunger 39 attached to piston [8. The plunger 39 is provided with an enlargement 40 adapted to rest on the surface of the pushrod 31 so as to cause the pushrod to raise the piston l8 when the throttle valve II is closed, thereby causing a charge of fuel to fiow into the cylinder l I when the throttle valve is open.

The plunger 39 has a vertical extension 42 extending above the enlargement 49 and terminating in a second enlargement 43 which is adapted to engage the upper side of the free end 44 of the thermostatic coil device 45 mounted upon a pin 46 extending from the surface of thecarburetor. The extension 42 is held against movement in the direction of its axis relative to the free end 44 of the thermostat by a pin 4| anchored in the plunger 39 below the free end of the thermostat and adjacent the head 43. The thermostatic device 45, which preferably comprises the coiled bimetallic resilient strip, has maximum strength when cold and is adapted to urge the piston l 8 downwardly when permitted to do so by opening of the throttle valve I l and simultaneous lowering of the push rod 31. This act causes theball check 20 to close the inlet l9 and the injection of an auxiliary charge of fuel through the jet 23 and prt 26. At a predetermined high temperature, preferably the maximum temperature to which the thermostat is subjected in normal operation of an engine, its fuel displacing action may be rendered either completely ineffective or reduced to a predetermined minimum value. During increase of the temperature to which 'the thermostat is exposed .from the low value at which it has maximum fuel displacingaction upon the plunger 39 to the upper temperaturelimit, the fuel displacing pressure as well as the length of the stroke of .the fuel displacing member is gradually delcreased. The decrease in pressure commences in response to changes .in temperature before the length of stroke of the fuel displacing element is varied. Therefore, the change in the discharge of the augmentingfuel supply is not severe or excessively sudden at any stage of engine operation between cold and fully heated lconditions.

I have illustrated'and described the present invention in connection with a downdraft car- .buretor of a certain type, and it should-be obwious to those skilled in the art that other types of carburetors may have the present invention incorporated therein by the use of simple modi- I have shown thethermostatic con- ;trol device as comprising a coiled bimetallic strip, -:but it should be readily apparent that other ther- 'mostatic control devices may be substituted therefor. The arrangement and character of the normal fuel supply means, the idle fuel supply means, and the injection device for the auxiliary acceleration fuel supply may be altered in accordance with the character of other types of carburetors without departing from my invention. I claim as my invention all such modifications in arrangement and detail as come within the, scope of the following claims and which may be readily apparent to those skilled in the art.

I claim:

1. A carburetor comprising a throttle valve, an acceleration pump comprising a piston and a cylinder in which said piston operates, a source of. fuel, an inlet connecting said cylinder to said source of fuel, a check valve in said inlet for preventing return of fuel through said inlet to said source of fuel, means connecting said piston to said throttle valve to raise said piston when said throttle valve is closed and thus cause fuel to flow into said cylinder, said means having one-way engagement only so that said throttlev valve may be opened without affecting the position of said piston, an outlet from said cylinder for conducting the fuel from said cylinder into the carburetor when the piston is returned, and means for variably returning said piston when said throttle valve is open comprising a bimetallic spring coil having one end anchored-to the outside ofv said carburetor and its free end connected to said piston so as to be uncoiled when said piston is raised, said bimetallic spring coil being arranged to contract when cold so as to exert greater pressure tending to return said piston when cold than when warm and to expand when warm so as to variably decrease the pressure exerted by said piston and the distance it may be returned in accordance with increases in temperature whereby the quantity of fuel and the pressure at which it is injected vary inversely as the temperature to which said bimetallic spring coil is subjected.

2. A carburetor comprising a throttle valve, an acceleration pump comprising a piston and a cylinder in which said piston operates, a source of fuel, an inlet connecting said cylinder to said source of fuel, a check valve in asid inlet for preventing return of fuel through said inlet to said source of fuel, means connecting said piston to said throttle valve to raise said piston when said throttle valve is closed and thus cause fuel to fiow into said cylinder, said means having one-way engagement only so that said throttle valve may be opened without affecting the position of said piston, an outlet from said cylinder for conducting the fuel from said cylinder into the carburetor when the piston is returned, and means for variably returning said piston when said throttle valve is open comprising a bimetallic spring coil having one end anchored to the outside of said carburetor and its free end connected to said piston so as to be deflected to a more loaded state when the piston is raised, said bimetallic spring being arranged to exert greater pressure tending to return said piston when cold than when warm and tending to deflect when warm so as to variably decrease the pressure exerted by said piston and the distance it may be returned in accordance with increases in temperature whereby the quantity of fuel and the pressure at which it is injected vary inversely as the temperature to which said bimetallic spring coil is subjected.

THOMAS M. BALL.

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