US2365910A - Carburetor - Google Patents

Description

E. H. SHAFF CARBURETOR Filed March 15, 1930 2 Sheets-Sheet l mi //5&

Patented Dec. 26, 1944 UNITED STATES PATENT orrlca CABIBURETOR Ernest H. Shall, Grand Haven, Mich, assignor to Bendix Products Corporation, South Bend, llnd., a corporation of Indiana i Application March 13, 1930, Serial No. 435,394

(El. i123- -11d) 33 Claims.

whereby such varying fuel requirements may be met with greater precision than has heretofore been possible.

Another object is to provide a carburetor having valve means for controlling the fuel mixture governed through automatic means. sensitive to both the suction of the engine and the movement of the air through the carburetor and embodying a thermostatic device arranged to modify the action of the automatic control means according to the temperature of the carburetor.

Another object is to provide a carburetor em bodying new and improved fuel discharg means arranged to insure proper atomization of the liquid fuel as it passes into the main body of the carburetor.

Other objects and advantages will become apthe constructions disclosed. In the ap ended cIaima-I aim to cover all modifications and alternative constructions falling within the scope of the invention.

In the drawings the invention is illustrated as embodied in a carburetor having a hollow body l providing an L-shaped passage made up of a horizontal air-intake portion It communicating with a vertical mixing and outlet portion l2. On the side opposite from the intake portion H, the body It has an upwardly opening cup-like reservoir l3, closed by a removable plate and providing a float-chamber l (Fig.

l) for containing a supply of liquid fuel. A

nipple l6, screwed into the bottom of the reservoir l3, forms a fuel inlet which'may be connected to the supply tank (not shown) and a valve l1 slidable in the nipple l6 and actuated by a pivoted float l8 in the chamber serves to maintain the fuel at a constant level indicated by the dotted line IS in Figs. 1 and 7.

Within the L-shaped passage of the carburetor a fuel discharge member (Figs. 1,3, and 4) is mounted which receives liquid fuel from the fio'at chamber [5 through a passage composed of a horizontal bore 2| extending angularly (Fig. 4) through the body ill from the chamber l5 to a vertical bore 22 extending downwardly through a vertical rib 23 onthe intake portion It. The upper end of the bore 22 opens at one side ,of the vertical outlet portion l2 of the body l0 and a vertically movable needle valve 24 is mounted in the bore 22 for operation from the outside of the body toward and from a seat 22* in the bore 22 below the end of the horizontal fuel passage 2L,

' In the bottom of the intake portion I l, a trans- Fig. 4 is a fragmental plan section taken along I the line 4-4 of Fig. l.

Fig. 5 is a side elevational view of the carin section.

Fig. 6 is an end elevational view taken from the right in Fig. 1, with parts broken away to show the interior construction.

be understood that this disclosure is given forthe purpose of illustratingthe invention and is not intended as a limitation of the inventionto buretor, certain of the fuel passages being shown I verse bore 25 (Figs. 4 and 6) is provided, connected at its opposite ends to the vertical bore '22 and the fuel discharge member 20. The fuel discharge member 20; preferably of tubular form, is screwed into'the bottom of the portion l I and extends upwardly beyond the fuel level l9. To control the amount of suction applied to the discharge member 20 and the amount of air '45 Fig. 7 is a side elevational view," partially indrawn past the member, a valve 30 is mounted in the discharge portion I2 of the body l0, above the member 20 and in' its preferred embodiment the valve is in the form of a contractile coiled spring (Fig. 1) "of conical form, having its larger outer coils secured in the counter-bored upper end of the portion l2 by a nut 3|, and its closed smaller end-extending downwardly into the carburetor. For-the. purpose of opening the valve the spring is adapted to be extended by means of a transverse rock shaft 32 mounted in therefrom and vaporize this fuel.

a projecting boss 33, and a lever 34 fixed on the shaft 32 and pivotally secured at its end to the pointed end of the valve 33. An operating lever 35 (Fig. 6) is fixed on the shaft 32 outside of the body Ill.

The present invention provides means for regulating the proportions of the fuel and air with such precision that they must be mixed thoroughly in order to insure even running of.the engine. The coiled spring throttle valve insures fuel and air, and makes it possible, as a practical matter to use automatic proportioning means which provides an unusually lean fuel mixture at all times.

When the valve 30 is opened air is drawn into the carburetor through the intake portion II and preferably the intake is formed so that at least a part of this air will be drawn past the end of the fuel discharge member 20 at a comparatively high velocity so as to draw liquid fuel To this end a horizontal division wall 36 (Figs. 1, 6 and '7) is provided in the intake portion ll, spaced upwardly from the bottom thereof and having an opening 3'! therein through which the fuel discharge member 20 projects. A vaporizing sleeve 38 screw threaded into the opening 31 in the wall 36, extends upwardly about the member 23 in spaced relation thereto, the sleeve terminating a short distance above the top of the member 23 and being flanged inwardly at 391so as to increase the speed oftheair moving therethrough.

In order to promote rapid and eiiicient vaporization of the liquid fuel drawn from the member 20, the upper end thereof is split to form a plurality of fingers 40 (Figs. ,1 and 3) which are bent radially outwardly so as to be in spaced relation to each other. with this construction a part of the liquid fuel will be drawn outwardly.

along and between the fingers 40 and will thus be directly in the path of the rapidly moving air so as to be'picked from the fingers 40 by the air and carried into the main body of the carburetor.

The rich primary mixture-of fuel and air thus formed may be mixed with a secondary supply of air so as to form a properly proportioned fuel mixture, and such secondary air may be drawn into the carburetor through a passage 4| (Figs. 1 and 6) formed between the division wall 35 and the top of the intake portion ll. Such secondary air passes upwardly about the sleeve 33, and'in order to insure proper mixing of the secondary'air and the primary fuel mixture, '9. Ven-. turi sleeve 42 (Figs. 1 and 3) is fixed in the a mixing portion of thebody III so as to project downwardly about the sleeve 33 in concentric spaced relation thereto.

As hereinbeforementioned. the liquid fuel supmy to the fuel discharge member 20 may be varied by the vertically movable needle valve 24, while the secondary air supply may be varied by means such as a fiaptype valve 43 (Figs. 1, 6 and 7) this result since it prevents stratification of the nally of the carburetor body I 0 for connection with the valves 24 and 43, and is arranged to be contracted by the suction of the engine. The

bellows 45 is of the sylphon type and tends to 8 expand longitudinally. The lower end of the bellows 45 is closed while at its upper end it carries a threaded nipple 46 screwed into an arm 51 projecting horizontally from the top of the portion 12 of the body l0 as shown in Figs. 2, 5 and 6. Thus, the bellows 45 is supported at the side of and parallel to the portion l2. Within the arm 45 a bore 50 is formed extending from the nipple 4 6 to the inside of the portion 12 above the valve 30 so that the interior of the bellows 45 will be subjected to the suction of the engine when the carburetor is connected to an engine manifold 5! as shown in Figs. 1, 5 and 6.

At its closed lower end the bellows 45 carries a lug 52 to which a lever member 53 is pivoted at 54 intermediate its ends, one of the ends of the lever 53 being pivoted at 55 upon the side of the.

body l5. Through the medium of the lever 53 the expansive and contractive movement of the bellows 45 is communicated to the two valves and 43, and this is preferably accomplished by means including a temperature responsive element arranged to modify the effect of the bellows upon one of the valves so as to provide a leaner fuel mixture as the temperature of the engine increases. In the form shown a bimetallic thermostatic element 56 has one end fixed upon the outer end 53 of the lever 53, while the body of the element extends along the lever and beyond the fixed pivot point 55 thereof. At its movable projecting end 56" the element 55 overlies an adjustable screw 51 (Fig. 5) mounted in the top of the valve 24. The valve 24 is pressed upwardly toward an open position and against the overlying end of element 56 by means of a spring 58 40 surrounding the valve in a counterbored portion of the bore 22.

It willbe seen that the thermostatic element.

55 and the lever member 53 function together as a single lever, and that by arranging the element so that the inner end 55* bends downwardly when heated, the opening of the valve 24 by the lever will be modified and the amount of fuel flowin past the valve will be varied in an inverse rela-.

to project substantially horizontally therefrom,

beneath-the movable outer end 53' of the lever 53. The lever. 59 is arranged so that when the outer end thereof is moved upwardly the valve 43 is opened, and a resilient connection between the outer end 53 of the lever 53 and the lever 53 is provided by an expansive spring 53 suitably secured to the two levers.

Thus when the bellows 45 is expanded due to slow degree of suction in the manifold, the outer end 53iof the lever 53 will be in its lowest position so gas to compress the spring 60. During idling or periods of slow engine operation, such compression of the spring 33 will hold the air valve 43 closed so that s cient air will pass through the sleeve 33 to insure proper operation of the carburetor. Howeyer, when the engine'is being operated at high speed, with the valve 33 open, the spring 53 will be compressed due to the low degree of suction in the manifold, but the yielding connection provided by the spring 50 75 will permit the air impinging against the valve aooaoio g able for idling. It will be understood that the M as it moves toward the bottom of the sleeve 38 to open the valve 43.

By reason of the compression of the spring 80 automatically provides a fuel mixture of sufficient richness to start an engine under most conditions, an auxiliary, manually controllable fuel supply is preferablyprovided for use in extremely cold weather. In the form shown a vertical bore 65 is formed in the body Ill, extending upwardly from the horizontal bore 2| of the fuel passage through the wall of the body portion 02, the bore 65 having a lateral extension 66 at its upper end (Figs. 2 and 5) whereby it communicates with the manifold above the throttle valve 30. Within the bore 65 a short distance above the fuel level l9, a jet nozzle 61! (Fig. 5) is positioned and a horizontal bore 68 extending through the body I from the bore 65 to the exterior of the body permits air to be drawn into the vertical bore past the nozzle so as to draw fuel therefrom. The operation of the auxiliary fuel nozzle 51 is controlled by a rotatable horizontal valve member 69 positioned in the bore 65 above the air inlet 68 and operable by a rod universally connected thereto. The provision of an auxiliary fuel discharge means, controllable independently of the automatic means is of great importance since it-renders it unnecessary to disturb the fine adjustment of the automatic means.

In Fig. '7 an alternative construction is shown having a fuel supply valve I5 having a screw threaded mounting at 16 to permit of manual adjustment thereof. A similar bellows 45" is provided which is connected to a similarly mounted lever 53". The bellows 45 in this embodiment is arranged to control an air valve 43 through a thermostatic element 56*. The thermostatic elemental; is fixed at one end to the lever 53 and is connected at its other end to the valve lever 59 by means of a spring 60'. The element 56b is arranged so that the compression on the spring- 60 is reduced as the engine temperature increases, whereby to vary the fuel mixture.

Operation When the engine is cold, the inner end 58.

of the thermostatic element 56 will be at its highest point and the fuel valve 24 will therefore .throttle valve 80 will normally be maintained in a slightly opened position to permit the passage of a small amount of fuel for idling purposes. The adjusting screw 51 may be utilized for varying the idling mixture. Since the bellows 45 is contracted during idling of the engine, the spring 60 will be under less compression so that the air valve 43 may be slightly opened by the air passing toward the lower air passage in the intake portion M. This permits more air to be drawn through the carburetor, but aless amount of air is drawn through the vaporizing sleeve 38 and as a result the fuel mixture will be rendered more lean.

When the car is placed in gear and the clutch engaged so as to put the engine under load, the engine speed of course; is reduced with a corresponding reduction in the engine suction. This permits the bellows to expand, causing the fuel valve 24 to be moved toward its open position and the air valve 43 to be closed. Thu a rich fuel mixture is provided as above described with reference to the engine starting operation.

As more speed is desired. the accelerator is advanced so as to open the throttle valve 30, whereby additional air is permitted to enter the manifold, causing the suction therein to be further reduced so that the bellows 45 may expand and open the fuel valve.

As the car gets under way, the rich fuel mix-. ture becomes unnecessary. Accordingly as the speed of the engine increases, an increased amount of air is drawn into the carburetor. This additional air impinges against the air valve 43 and tends to open it against the compression of the spring 60, and acting through the lever 53' tends to close the fuel valve slightly. Such an action is, of course, desirable since the increased velocity of the air passing the fuel discharge amount of air which may be drawn through the be opened to its greatest extent. ,As the engine is I cranked, very little suction is created in the man ifold so that the bellows will remain in its extended position and the fuel valve 24 will be open to it greatest extent. The air valve 43 will also "be held in closed position by the action of-the spring ill which isthen compressedby the expansion of the'bellows 45. All'of the air passing,

into the carburetor will therefore pass through the sleeve 38 and will be eifective in drawing fuel from the discharge member 20.

As soon as the engine begins firing, it will turn over more rapidly, thereby increasing the degree of suction the manifold and acting through the bellows 45 to move the fuel valve 24 to its idle position so as to reduce the amount of fuel available and thus provide for a lean fuel mixture suitvalve will have reached the maximum and the ,engine suction will increase so as to contract the bellows 43. Thus the fuel valve'24 will be moved slightly toward closed position so that a. relatively lean fuel mixture will be supplied for maintaining the speed attained. 1

From the foregoing it will be apparent that the invention provides a carburetor having an improved apparatus for automatically varying the richness of the fuel mixture in accordance with the requirements oi the engine. It will also be seen that the improved fuel discharge meansginsures more eiilicent vaporization of the fuel than heretofore.

It will be apparent that the'air control ,valve is actuated in such a manner that the fuel mixture will be more nearly in accordance with-theorigine requirements than has heretofore been pos'- sible. This is due to the fact that the suction of the engine, taken from above the throttle valve, is applied to the valve through a resilient connec tion so that the air moving through the secondary the present carburetor furnishes to the manifold a supp y of thoroughly mixed fuel and air which is as lean as may be used and which will cause the engine to run evenly.

A portion of the subject-matter herein shown and described is claimed in my copending application Serial No. 212,738, flled June 9, 1938.

I claim as my invention:

A carburetor comprising, in combination, a hollow body having intake and discharge openings, a fuel discharge member in said body, a throttle valve for said discharge opening, means providing a primary air passage constantly open during operation of the engine from said intake opening past said member, means providing a secondary air passage from said intake opening into said body, aflap type air valve for controlling said secondary air passage, and means for controlling said flap valve comprising a movable diaphragm adapted to be connected at one side to an engine manifold so that said throttle valve lies between said fuel discharge member and the point of connection of said diaphragm with the manifold, andresilient means forming an operative connection between said diaphragm and said flop valve, and tending yieldingly to move said valve toward closed position when the suction in the engine is reduced.

2. A carburetor comprising, in combination,

a hollow body having intake and discharge openings, fuel discharge means in said body, a throttle valve between said fuel discharge means and said discharge opening, means providing a primary air passage constantly open during operation of the engine from said intake opening past said fuel discharge means, means providing a secondary air passage from said intake opening into said body, a valve in said secondary air passage arranged so that suction in said carburetor tends to open said valve, a pressure responsive device mounted on said body and adapted for connection with an engine manifold with said throttle valve lying between said fuel discharge means and the point of connection of said device with the manifold so that the engine suction tends to move said. device, and a resilient connection between said device and said air valve y wherebysaid device tends to close said air valve charge member and said discharge opening comprising a spiral cone-shaped extensible member capable of substantially closing said discharge opening, and extensible to vary the effective area of the opening.

4. A carburetor having, in combination. a hol-' low body havinga discharge opening therein, a fuel discharge member in said body, a valve for controlling the flow ofliquid fuel to said membar, a pressure responsive device adapted for direct connection with an intake manifold and connected to said valve so as to tend to open said valve when'the suction insaid manifold dem m g Pr viding a e constantly open during operation of the engine from the outside of said body for primary air arranged to direct said air past said discharge member,

vmeans providing a passage for secondary air from the outside of said body, automatically operable suction controlled valve means for controlling said secondary air passage, and a combined throttle valve and mixing device mounted between said fuel discharge member and said discharge opening constructed to provide passage for the air and fuel through said combined valve adjacent to the center of the valve as well as through the sides thereof.

5. In a carburetor having a hollow body with intake and discharge openings therein, a fuel discharge member in said body with a fuel supply passageleading thereto, a valve for controlling said passage, a throttle valve operable independently of said fuel control valve and mounted in said body between said fuel discharge member and said discharge opening, suction responsive means communicating with said body between said throttle valve and said discharge opening, means connecting said suction responsive means to said fuel valve operable to close said valve when the engine suction increases, an air valve for controlling said intake opening, and a resilient connection between said suction responsive means and said air valve acting to move said air valve yieldingly toward its closed position as the fuel valve opens under the control of said suc-.

tion responsive means.

6. In a carburetor having a hollow body with intake and discharge openings therein, a fuel' discharge member in said body with a fuel supply passage leading thereto, a fuel valve for controlling said passage, a throttle operable independently of said fuel control valve and mounted in said body between said fuel discharge member and said discharge opening, suction responsive means communicating with said body between said throttle and said discharge opening, means connecting said suction responsive means to said fuel valve operable to move said valve toward closed position as the engine suction increases, an air'valve for controlling said intake opening, and a resilient connection between said suction responsive means and said -air valve acting to move said air valve yieldingly toward its closed position as the fuel valve opens under the control of said suction responsive means, the connection between the suction responsive means and one of said valves embodynecting said device to said fuel valve whereby ing a thermostatic device arranged to modify the action of said suction responsive device upon said one valve.

7. A carburetor having a hollow body with inlet and outlet openings, a fuel discharge memher in said body, means providing a fuel passage to said member, a valve for controlling said passage, means in said body providing a primary air passage constantly open during operation of the engine from said inlet opening past said fueldischarge member, and also providing a-secondary air passage into said carburetor, a valve of the flap type in said secondary air passage-arranged so that suction in said carburetor tends to open said valve, 9. pressure responsive device mounted onsaid body normally tending to as- I sume one position and adapted for connection with the manifold so that the engine suction will move said device from said position, means consaid device permits said valve to move toward its open position whenthe engine suction is reduced, and alresilient connection between said aseaaio air valve and said device whereby movement of said air valve toward its open position acts yieldin'gly to modify ,the action of said device upon said fuel valve.

8. A carburetor having a hollow body with inlet and outlet openings, a fuel discharge member in said body, means providinga fuel passage to said member, a valve for controlling said and a resilient connection between said air valve and said device whereby movement of said air heat and suction for operating said valve to lean out the mixture at high temperatures and suctions and enrich said mixture at low temperavalve toward its open position acts yieldingly to modify the action of said device.

a. In a carburetor having a-hollow body with inlet and discharge openings, a fuel discharge member comprising a vertical tube having spaced fingers projecting radially outwardly from the upper edge thereof, and a-sleeve surrounding said tube and communicating with said inlet opening, said sleeve extending upwardly beyond the top of said tube and having an annular flange projecting inwardly therefrom so as to overly the ends of said fingers.

10. A carburetor comprising, in combination, a hollow body having an intake and an outlet opening therein and providing a passage therebetween, a fuel discharge member therein, a combined throttle valve and mixing device mounted in said passage between said discharge member and said outlet opening, said valve comprising a spiral, cone-shaped extensible member capable of substantially closingv said passage and extensible to vary the effective area of the passage, said member having its pointed end directed away from said outlet opening, and

means for operating'said member comprising a transverse rock shaft mounted in said body at one side of said passage, and an arm fixed on and projecting from said shaft transversely of said passage and connected to said device;

11. In a carburetor, means forming a, mixing conduit, said conduit including an air inlet, a

fuel inlet, and a mixture outlet, a manually operated valve for said conduit, a valve for controlling the flow through one of said. inlets to operating said valve in accordance with thetemperature to lean out the mixture upon an' intures and suctions, and a suction connection leading from a point in said mixing conduit posterior to said first-named valve for operating said mixture controlling valve.

13. In a carburetor, means forming a mixing conduit, air and fuel inlets for said conduit, valve means for-controlling, each of said inlets to enrich the fuel mixture ratio under abnormal operating conditions, one of said valves being responsive to suction and being operable by suction to move it to the normal operating position,

and one of said valves being operatedin re sponse to temperature changes whereby it will be moved to its normal operating position when the temperature reaches normal.

14. Control mechanism for a carburetor of an internal combustion engine, comprising a pressure-responsive choke valve, yielding temperature-responsive means operative to close the valve, and means responsive to manifoldsuction to vary the effectiveness of the temperatureresponsive means.

15. Control mechanism for a carburetor of an internal combustion engine, comprising a pressure-responsive choke valve, temperature-responsive means tending to close said valve, and means responsive to a fluid pressure generated by the engine for varying the effectiveness of the temperature-responsive means.

16. In combination with an internal combus-- tion engine, a carburetor having a pressure-responsive choke valve, temperature-responsive means yieldingly urging the valve toward closed position, releasable means cooperating with the temperature-responsive means for holding the valve in closed position, and means responsive to a function of engine speed for releasing the releasable means.

17. In a. carburetion system for an internal combustion engine, a pressure actuated air valve, means preventing opening of the valve at relatively low pressures, yielding temperature-responsive means tending to close the valve, and suction operatedmeans for rendering the firstnamed means less eflective.

18. In combination with an internal combustion engine having a carburetor and an intake manifold, an adjustable mixture-enriching device for said carburetor, a movable member, temperature responsive means acting between said movable member and said device, and means responsive to variations in the subatmospheric pressure .created in said intake manifold by selfoperation of the engine for moving said member crease oftemperature, and means for operat- I by said carburetor, means responsive to both in one direction when the pressure increases and in the other direction when the pressure decreases.

19. A means for starting an internal combustion engine under various conditions of temperature, which comprises an intake pipe for an engine, carburetor means connected to said inclosing position by a pressure intermediate the maximum and minimum subatmospheric pressures created in said intake pipe by the selfoperation of the engine, and a thermostat subject to the temperature of the engine for varying the position of'said valve.

20. In a carburetor for an internal combustion engine, an induction passage having an air inlet and a mixture outlet, an unbalanced choke valve controlling the inlet, a throttle controlling the outlet, and means for variably biasing said choke valve toward closed position during self-operationof the engine in accordance with variations in engine temperature and also in accordance.

with variations in pressure in the passage posterior to the throttle.

21. Control means for an internal combustion engine carburetor having an air intake, comprising a valve controlling inflow of air through said air'intake and tending to open under the influence of airflow therethrough, means including atemperature responsive member yieldingly urging said valve toward closed position when cold in opposition to the force of the airflow past said valve, and a device responsive to manifold vacuum having a movable wall preventing inflow of air at all positions, said wall being connected to the valve and exerting a force thereon varying from zero to maximum with vari-- ations in the manifold vacuum, the effect of an increase in manifold vacuum being to decrease the richness of the mixture, said valve, temperature responsive member, and device being so constructed and arranged as to cooperate in maintaining the valve in partially open positions during the warming up period of self-operation of the engine.

22. In a carburetor, means forming a mixing conduit, said conduit including an air inlet, a fuel inlet. and a mixture outlet, a manually operated valve for said conduit, a valve for controlling the flow through one of said inlets to enrich or lean out the fuel mixture discharged by said carburetor, a thermostat for operating said second valve in accordance with temperature changes to enrich the mixture when the temperature is low, means connected with the mixing conduit and movable by a pressure intermediate the maximum and minimum subatmospheric pressures created in said conduit durin self-operation of the engine, and means connecting th last means with the second valve.

23. In combinat on with an internal combustion engine having a carburetor, an adjustable mixture-enriching device for said carburetor, a movable member, temperature-responsive means acting between said movable member and said devic and nonres liently connected to the lat-' ter, and means associated with the engine for moving said member in one direction when the en ine is running and in the other direction when the engine stops.

24. In combination with an internal combustion engine having a carburetor, an adjustable mixture-enriching device. for said carburetor, a movable member, temperature-responsive means acting between said movable member and said device and nonresiliently connected to the latter, said movable member being movable between two positions in the first of which it adlusts said mixture-enriching device to cause production of a relatively rich mixture and in the second of which it adjusts said mixture-enriching device to cause production of a relatively lean mixture, and means associated with said engine .for controlling the position of said mova e member and acting to maintain said movable member in said first position when the englne'is being cranked and in said second position when the engine is running under its own power.

25. In a carburetor, means forming a mixing conduit, said conduit including an air inlet. a fuel inlet, and a mixture outlet, is throttle valve for said conduit to control the flow of mixture therethrough, a valve in the air inlet to control the richness of the mixture discharged by the carburetor, the last named valve including an eccentrically pivoted valve part so arranged that suction in the carburetor tends to open it, means responsive to temperature operatively connected to the last named valve yieldingly to urge the valve closed with greater force at low than at high temperature, and means movable in response to suction posterior to the throttle valve and operatively connected to the last named valve to lean out the mixture upon an increase in suction posterior to the throttle.

26. In a carburetor, means forming a'mixing conduit, said conduit including an air inlet, a fuel inlet and a mixture outlet, a throttle valve for said conduit to control the flow 'of mixture therethrough, a choke valve in the air inlet to control the richness of the mixture discharged by the carburetor, the choke valve including an eccentrically pivoted valve part which is movable toward open position by direct action of suction thereon, a pivoted lever operatively connected to the choke valve to control it, heat responsive means operatlvely connected to the choke valve to urge it closed with greater force at low temperature than at high temperature, and means movable in response to suction posterior to the throttle valve and connected to said lever to move 7 it in a direction corresponding to opening of the choke valve upon an increase in suction posterior to the throttle.

27. In a carburetor, means forming a mixing conduit, said conduit including an air inlet, a

. fuel inlet, and a mixture outlet, a throttle con means including a suction conduit connected to a point in the mixing conduit posterior to the throttle.

, 28. In a carburetor, means forming a mixing conduit, said conduit including air inlet, a fuel inlet, and a mixture outlet, a throttle valve for said conduit, 9. pressure-responsive valve for controlling the flow throughsaid air inlet to vary the richness of the fuel mixture generated by the carburetor, temperature responsive mesnsfor influencing the operation of said second valve in accordance with temperature changes to enrich the mixture when the temperature is low, a device connected with the mixing conduit and movable by a. pressure intermediate the maximum and minimum subahnospheric pressures created in the conduit during self-operation of the engine.

and an operative connection between said device and the second valve.

29. In a carburetor, means forming a mixing conduit, means forming a venturi in said mixing conduit. 9. main fuel nozzle discharging into said venturi, a throttle controlling the discharge of mixture from, said carburetor, a second fuel nozzle discharging into said mixing conduit adjacent said throttle valve,-a valve for controlling the admission of air to said conduit, said .valve being movable toward open position by direct action of suction, suction controlled means operatively connected to said valve, a thermostat operatively connected to said valve and tending to close said valve with a force which decreases with increase in temperature, theccnnection between said thermostat and said valve permitting said thermostat to continue to move after the movement of the valve has been arrested.

30. In a. carburetor, an induction passage having an air inlet, a valve controlling the air inlet, a throttle controlling the outlet of the induction tion, said temperature and suction responsive devices and valve being so constructed and arranged that the valve closing force of the temperatureresponsive means is opposed by the valve opening force 'of the suction responsive means and the valve is positioned in accordance with the equilibrium established by the forces of the temperature and suction responsive means.

passage, a pair of fuel nozzles discharging into the induction passage'one discharging adjacent said throttle and the other discharging between said valve and said throttle, a bimetallic thermostat having an overrunning connection with said a manually operated throttle controlling the outlet, a valve for controlling the inlet, a temperature responsive device operatively connected with said valve and tending-to close the valve with a force increasing with decrease in temperature, a suction responsive device operatively connected with said valve and having a suction conduit connected to a point in the mixing conduit posterior valve and adapted to close it when cold and to permit it to open when hot, a suction device 32. In a carburetor, a conduit having an air inlet and a mixture outlet, a throttle controlling the outlet, an unbalanced valve controlling the inlet, a thermostat operatively connected to thevalve and urging said valve in the closing direction with increasing force as the temperature thereof drops, a' suction responsive device connected with the conduit posterior to the throttle and operatively connected with the valve, said device being so constructed and arranged as to actuate the thermostat in such a manner that the closing force of the thermostat and the force of the suction device are-opposed and are adapted to reach a state of equilibrium in accordance with attendant temperature and suction conditions, the quantity of air admitted by the valve being determined by said equilibrium established between the temperature and suction responsive device.

33. In a carburetor, means forming a mixing I conduit, means forming a venturi in said mixing conduit, a main fuel nozzle discharging into said. venturi, a throttle controlling the discharge of mixture from said carburetor, a second fuel nozzle discharging into said mixing conduit adjacent said throttle valve, a choke valve for controlling the admission of air to said conduit, said choke valve including a part which is movable toward open position by direct action of suction, a suction operated device operatively connected to said choke in such a manner as to tend to produce 40 opening of the choke upon increase of suction,

to the manually operated throttle tending to 1 cause opening of the valve upon increase in sucand a thermostat operatively connected to said choke. ERNEST H. SHAFF.

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