US2163904A - Carburetor - Google Patents

Description

June 27, 1939. A. H. wlNKLER 2,163,904

IN VEN TOR. Azfer H. WIN/are ATTORNEK June 27, 1939. A, H wlNKLER CARBURETOR Filed Sept. 18, 1935 3 Sheets-Sheet 2 INVENTOR. EQT figg/Mae Il ATTORNEY @if @a June 27, 1939. A. H. wlNKLER CARBURETOR .Filed Sept. 18, 1935 3 Sheets-Sheet 3 R. 2M/m NE N EL M c..T Il T W%A T Q Q E my AB Patented June 27, 1939 UNITED STATES PATENT lQFFICE Bendix Products Corporation,

South Bend,

Ind., a corporation of Indiana Application September 18, 1935, Serial No. 41,033

1 Claim.

This invention relates to carburetors, and more particularly to devices for automatically controlling the richness and quantity of the mixture produced by internal combustion engine carburetors, as in starting and warming up a cold engine.

Such devices are commonly referred to as automatic chokes, and operate the control the position of the choke valve in accordance with temperature, engine speed, and/or other factors.

In the present invention, the richness of the 4mixture is controlled by an unbalanced choke valve the position of which is varied in accordance with temperature, rate of air flow and other factors, while theminlmum engine speed is controlled by the position of a throttle valve whichl is moved to a partly open position for starting, and to its normal closed position when the engine is operating under its own power, while a bypass around the throttleprovides for the flow of an abnormal quantity of fuel mixture to give a fast idlewhile the engine is warming up.

A thermostat is provided which opposes opening movement of the choke valve while the engine is being cranked, but which is, by suitable mechanism, limited in its action after the engine has been started, the operation of the choke valve being then chiefly controlled by a spring the stiffness of which does not vary with temperature, and which is connected in series with the thermostat. These results are accomplished by means of the improved mechanism now to be described, and shown in the appended drawings, in which:

Figure l is a vertical view, partly in section, of a carburetor and automatic choke embodying the invention;

Figure 2 is a detail view of the automatic choke mechanism, taken on the line 2--2 of Figure l, but showing the parts in the positions they occupy before the cold engine has Abeen started.

Figure 3 is a view similar to Figure 2, but showing the mechanism in starting position;

Figure 4 is a similar view, showing the parts in the positions they occupy during the warming-up period;

Figure 5 is a similar view, showing the mechanism in position for deooding the engine;

Figure 6 is a fragmentary View, similar to Figures 2-5, but showing the mechanism in position -28 in oli-center relation, so that suction within barrel type having a single air-horn and two primary Venturis I2 discharging into secondary venturis I4, which in turn discharge into parallel mixing chambers I6 controlled by twin throttles I8 preferably mounted upon a common shaft 20. Fuel is supplied to the carburetor through. main nozzles 22 which discharge within the Venturis I2, and through any suitable idling system, not shown. All of the elements thus far described may be of any suitable construction since they. form, per se, no part of the present invention.

'I'he air inlet 24 of the carburetor is controlled by a choke valve 26 which is mounted on its shaft the carburetor, produced by the pumping action of the engine cylinders, tends to move the choke valve toopen position. A pressure responsive poppet valve 30, of known construction, may if desired be provided to control an opening in the choke valve.

A stamping or bracket 32 is xed to the choke valve and a link 3d is pivoted thereto by a pin 36, and extends downwardly through a slot in the choke valve. At its lower end, link 34 is pivoted to the upper end of a rod 38, which is formed integral with a piston reciprocably mounted in a cylinder d0 cast in the carburetor body between the mixing chambers I6. T'he said piston comprises an upper cylindrical portion t2 and a lower cylindrical portion M, connected by a reduced portion 46.

From each of the mixing chambers I0 anterior to the throttle leads a duct t@ to the cylinder 40, and a duct 50 leads from the cylinder 40 to each of the carburetor barrels posterior to the throttle. A fuel jet 5l discharges into these passages, as disclosed in Patent Number 2,031,709, issued February-25, 1936 to S. F. Hunt. It will be seen that when the piston M, M is in the position shown in Figure l it will permit a substantial amount of fuel mixture'to bypass the throttles. thus permitting the engine to idle at a faster rate when'the choke valve is closed.

A plate 52 is'attached to the outside of the carburetor and supports in spaced relation a second plate 54 which has mounted thereon a thermostat casing 56. Casing 56 carries a pin 58 to which is hooked the outer end of a coiled thermostatic spring 60, the inner end being xed to a shaft 62 which is journaled in a fixed sleeve 63 mounted in plate 54. Casing 5B may be supplied through duct 64`with heated air from a stove on the exhaust manifold, as described in Stuyvesant C. Smith, Patent 2,030,331, or may 55 be heated electrically or in any other suitable manner.

The inner end of shaft 62 has fixed thereto an annular boss 65, and a member having upwardly extending spaced stops 68, 10, a cam portion 1|, and a downwardly extending cam projection 12. The choke shaft 28 has fixed thereto a member 14 having a downwardly extending cam projection 18 and a pin 18 xed to its upper portion and extending between the stops 68, 10, so that the stops yieldingly limit the opening and closing movements of the choke valve. A coiled spring has its inner end iixed to boss 65 and its outer end xed to pin 18 so as to constantly urge the latter in such direction as to tend to close the choke valve.

The control mechanism thus far described opcrates as follows. The thermostat when cold exerts a yielding force on stops 68, 10 in the clockwise direction as viewed in Figures 2 to 6. This causes stop 68 to contact pin 18 and exert a force tending to rotate the choke valve to the closed position, the force of spring 80 being of negligible effect on the operation. Opposing said force, during the operation of the engine, may be the pressure of air on the unbalanced choke valve tending to open the same.

Throttle shaft 20 is provided at one end with the usual manual control mechanism, not shown, and at its other end has fixed thereto an arm 82. A rod 84 has its lower end pivoted to the outer end of arm 82 and its upper end is slotted to receive in sliding relation a guide pin 85 which is mounted on plate 52. Rod 84 is provided with horizontally projecting studs-88, 81, and 88 for a purpose to be described. A member 89 is pivotally mounted on pin 85 and carries at its upper end a pin 90 designed to actuate projection 16 as described hereinafter. At its lower end member 89 is provided with a horizontally extending stop member 92 designed to cooperate with stud 88 in limiting the closing movement of the throttle, as described hereinafter. Member 89 is also provided with a cam member 94 which cooperates with stud 88 under certain conditions ofy operation. A pin-and-slot arrangement 95 (Figure 3) is provided to limit the movement of member 89. In order to insure that member 89 will remain in one or the other of its extreme positions, a dead-center mechanism is provided, comprising a spring 96 and a curved link 98 connecting pins |00 and |02 fixed respectively to plate 52 and member 89 on opposite sides of pin 85. A suitable friction mechanism may be substituted for the dead-center mechanism, if desired.

Operation-When the motor has been shut off and the car allowed to stand at low atmospheric temperature, thermostat |50 will uncoil and, through shaft 62, stop 68, pin 18 and arm 14, Will move the choke valve 26 toward its closed position, but member 89 will be held in its clockwise position by the contact of stop 92 with stud 88, as shown in Figure 2, and pin 90 will prevent member 16 moving in the clockwise` direction sufiiciently to permit the choke valve to close fully. If now the operator actuates the starter, the throttles will be partially opened, either manually or automatically by mechanism well known in the art, and this will move rod 84 to or beyond the position shown in Figure 3, the throttles being moved to or beyond the position indicated at A in that iigure. As soon as stud 88 passes upwardly beyond stop 92, the thermo- ,stat, acting through shaft 62, Stop 63, member 16 and pin 90, is free to move member 89 counterclockwise to the position shown in Figure 3, wherein the Stop 92 moves into the path of stop 88 and prevents return of the throttle beyond position A. At the same time, the choke valve will be urged toward fully closed position by the thermostat, and the bypass 48, 50 will be open as described above. This condition will obtain (except for such opening movement of the choke Valve as will be caused by the suction due to cranking) until the engine fires, whereupon its speed will gradually increase as the viscosity of the oilin the crankcase and elsewhere is decreased due to agitation, until an engine speed corresponding to a vehicle speed of, say, 20 M. P. H. is attained. At such speed, the danger of the engine stalling is largely past, and the operator, without the necessity for instructions, will open the throttle wider, which will cause stop 88 to strike cam 94 and move the latter clockwise until member 89 is moved past its dead-center position to the position shown in Figure 4. During such movement of member 89, pin 90 will move to the position shown in Figure 3, Where it positively limits the closing movement of the choke valve. The parts will remain in approximately this position if the engine continues running, and there will be suflicient air flowing through the carburetor, and sufficient manifold vacuum acting on piston 42, 44, to cause the choke valve to oscillate between the positions shown respectively in full and dotted lines in Figure 4, against the constant force of spring 80 and the gradually decreasing force of thermostat 60. The throttle may then be returned to its fully closed position, indicated at B in Figure 3, although the bypass 48, 50, being open, will provide suiiicient mixture to keep the engine running at a speed corresponding, say, to 10 M. P. H. If the engine stalls or if the ignition switch is opened While the throttle is thus closed, the choke valve is free to return to its original position, in which case member 16 contacts pin 90 and moves member 89 past dead-center in the counterclockwise direction, thus restoring the parts to their original positions, shown in Figure 3.

With the parts in their original positions, if the cylinders have been flooded with an excess of fuel, the operator opens the throttle wide open. This moves stop 86 into contact with cam surface 1|, which positively rotates stops 68 and 10 in the counterclockwise direction so as to positively move the choke valve to a partially open position, as shown in Figure 5, and permit it to open further by merely overcoming the force of spring 80. If the engine is then cranked with the throttle fully open, the choke will be drawn open by the iiow of air yand the flooded condition will be relieved.

Even if the engine has warmed up in cold weather when climbing a long hill with the throttle wide open and insuicient flow through the exhaust manifold to keep the thermostat heated, the choke valve may tend to close, which would cause the mixture to become--overrich. In order to prevent this, the arrangementv shown in Figure 6 is provided, wherein it Will be seen that if the throttle is moved to wide open position when the choke valve is fully opened, stud 81 will engage member 12 and positively hold the choke valve wide open.

It will be seen that with any throttle opening sucient to bring stud 86 into contact with cam 1|, the closing movement of the choke valve is positively limited at the point where pin 18 contacts stop Il, as seen in Figure 5. The choke, by merely overcoming the force of spring I0, may then open to the point where pin 18 contacts stop, whereupon, in order to open turther, it must overcome thel force of thermostat lBil.' Since, at low temperatures, the thermostat is considerably stiller than spring Il), the result will be that the spring' 80 alone will largely control the choke valve position during the warming-up period.

Although the invention has been described with particular reference to a specic embodiment thereof, it is not limited thereto or otherwise except in accordance with the language of the appended claim. y

I claim:

In an internal combustion engine carburetor, a pressure responsive choke valve, temperature responsive means urging. the choke valve closed, a lost motion connection between the temperature responsive means and the choke valve, yielding means connected in series with the temperature responsive means and mounted concentrically therewith urging the choke valve closed, and means controlled by throttle position for rendering said last mentioned means inoperative to close the choke valve beyond a predetermined point.

ALBERT H. WINKLER.

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