US2705484A - Mechanism for controlling the starting and operation of internal combustion engines - Google Patents

Description

4 l w a m 0 m 2 w Aprll 1955 P. J. JORGENSEN ET AL MECHANISM FOR CONTROLLING THE STARTING AND I OPERATION OF INTERNAL COMBUSTION ENGINES Flled Jan 8 1932 /3 y El TOR Nan/fo/d April 5, 1955 Filed Jan,

P J. JORGENSEN ET AL MECHANISM FOR CONTROLLING THE STARTING AND OPERATION OF INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet 2 ATTORNEY-S P 5, 1955 P J JORGENSEN ETAL 2,705,484

MECHANISM 'Fok CONTROLLING THE STARTING AND OPERATION OF INTERNAL COMBUSTION ENGINES Filed Jan. 8, 19:52 3 sheets-sheet a Unitcd States Patent MECHANISM FOR CONTROLLING THE START- ING AND OPERATION OF INTERNAL COMBUS- TION ENGINES Peter J. Jorgensen, Chicago, and Clarence H. Jorgensen, Elmhurst, 11].; Clarence H. Jorgensen, administrator of said Peter J. Jorgensen, deceased, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application January 8, 1932, Serial No. 585,510

68 Claims. (Cl. 123-119) This invention relates to internal combustion engines, particularly to mechanism for controlling the starting and subsequent operation thereof and more particularly during the period the engine is warming up to normal operating temperature.

The carburetor associated with an internal combustion engine will provide, automatically, after the engine is started, has properly warmed up and is operating at normal running temperature, a substantially correct mixture of air and fuel to effect proper engine operation under the usual variable conditions of speed, load, acceleration, etc. For starting and for all engine operations it is necessary to introduce into the engine intake fuel and air to form a combustible mixture. For starting, however, if the engine temperature is lower than the normal running temperature, it is necessary to supply a greater proportion of fuel to air than is required to form the normal running mixture and, when the engine is at much lower than normal running temperature, as when starting initially in cold weather, a very much greater proportion of fuel to air is required because, when starting at low temperatures, only a part of the fuel introduced into the engine intake is vaporized. What is introduced into the engine intake for starting at low temperatures is generally termed a rich or enriched mixture because of the greater than normal running proportion of fuel to air which is supplied.

During the warm-up period, after the engine becomes self-operative, the ratio of fuel to air should be gradually reduced, generally termed a leaning out of the mixture, as the engine temperature progressively increases until such ratio bcomes that of the normal running mixture when the engine attains its normal operating temperature. It has been customary to control the relative proportions of fuel and air introduced into the intake for starting and warm-up operation by manual actuation of what is termed a choke valve, either an air valve or a fuel valve. It has been found difficult to manually operate such a valve without providing too much or too little fuel relative to the quantity of air supplied, with the result that starting was not only made difficult, but the engine was likely to operate unsatisfactorily and even stall after it began to run.

The conditions during starting of an engine, hot or cold, are necessarily different from what they are after the engine is warmed up and is running. Cranking speed is inherently slow, and hence the suction, which the engine can produce, is also inherently low. Starting is further dependent upon engine temperature, because the extent of fuel vaporization also depends upon engine temperature. In manual operation of a choke valve, the operator had to depend upon his judgement of conditions to properly position the choke valve to obtain the proper flow of additional fuel into the intake manifold to effect satisfactory starting, and to re-position the choke valve after the engine is running to progressively reduce the quantity of additional fuel supplied, so as to provide a decreasingly rich mixture. The primary object, of course, is to produce a fuel-to-air ratio which is relatively rich on starting, so that a sufiicient quantity of fuel will be vaporized to be readily ignitible, and to gradually reduce the richness of the mixture as the engine warms up after it is running.

One of the objects of this invention, therefore, is to provide mechanism for automatically controlling the ice starting and subsequent operation of an internal combustion engine, particularly during the warm-up period; more specifically, to provide mechanism for automatically controlling the richness of the mixture of fuel and air discharged by the carburetor of an internal combustion engine, in response to temperature and vacuum conditions of the engine so as to eliminate the ordinary hand choke arrangement normally used.

Another object of the present invention is to provide automatic means for regulating the carburetor according to the conditions of the engine to meet the usual conditions of operation which have heretofore required manual adjustment of the choke, primer, or the like, and also to meet and correct improper operation such as excessive opening of the throttle, either during starting or running, in an attempt to accelerate to greater amount than the engine will perform.

Further objects will appear from the detail description, taken in connection with the accompanying drawings, in which will be set forth illustrative embodiments of this invention; it will, however, be understood that this invention is susceptible of various other embodiments, within the scope of the appended claims.

The starting and operating of an internal combustion engine may be divided into four typical stages, each of which requires individual treatment and each of which requires a corresponding treatment of the fuel to air ratio. The fuel to air ratio should unquestionably be greater on starting, or when the engine temperature is low, or when acceleration is desired, accordingly the skill of the ordinary operator of the engine to produce optimum conditions cannot be relied upon. These various conditions often rapidly succeed each other, and the automatic control must operate rapidly and effectively to meet them as they occur and to differentiate between them.

The first definite condition is that encountered in cranking the engine, either hot or cold, and the feeding of fuel to it for the purpose of initiating firing and operation under its own power. This first condition constitutes a range in itself, since the engine may be at any temperature from that of the surrounding atmosphere to the temperature of a normally warmed up engine.

The second condition is that prevailing immediately after the engine has begun to fire and is operating under its own power, in part at least, and is warming to its normal operating temperature. This also covers a range of temperatures.

The third condition is that prevailing after the engine has become heated up to a normal operating temperature and is capable of operating under normal load.

The fourth condition to be considered is that of acceleration, that is, causing the engine to exert a sudden great effort as for speeding up of the vehicle under various loads.

While we mention these as separate conditions they may overlap and merge to a certain extent, dependent upon what the operator desires to accomplish.

In regard to the matter of starting the engine, the arrival at a suitable explosive mixture for initiating firing may be treated as mainly dependent upon the introduction into the intake passage leading to the cylinders of a sufficient quantity of fuel to insure that enough of such fuel will vaporize to form the required quantity of ignitible mxiture necessary for starting purposes.

Generally stated, and in accordance with an illustrative embodiment of this invention, mechanism is provided for automatically controlling the richness of the mixture of the fuel and air discharged by the carburetor of an internal combustion engine in response to temperature and vacuum conditions of the engine so as to eliminate the ordinary manually operated choke arrangement which is generally used.

In the particular embodiment of the invention which is shown and described herein, a choke in the form of an air valve in the intake of the carburetor is connected for control by the joint operation of a suction motor, connected with the intake manifold by a suction conduit, and a thermostat subject to the heat of the engine, viz. from the exhaust manifold. The function of varying the fuel-to-air ratio may, however, be secured by means controlling the fuel supply, as by opening an auxiliary fuel passage, operating a fuel-controlling needle valve, or the like. Such means as above described represent equivalent ways in which control of the fuel-air ratio of the mixture can be effected and either can be employed to supply a richer than normal mixture to the engine intake. In either case, normally, and when the engine is cold, with the air valve closed or w1th the fuel valve opened, more than in the, normal operation, a rich mixture will be delivered to the engine for starting purposes. In accordance with an illustrative embod1- ment of this invention, after the engine has started, resulting in a reduced pressure. in the intake manifold, the suction motor will operate on the valve to initially reduce the richness of the mixture. As the engine warms up, the thermostat will operate on the valve to progressively reduce the richness of the mixture, and ult mately, when normal operating temperature is reached, w1ll pos1- tion the valve to provide the normal running mixture.

Upon acceleration, the pressure in the intake manifold rises, or, in other words, the suction is reduced, and the reduction in suction is utilized to temporarily increase the richness of the mixture. In the disclosed embodiment of the invention, a separate suction motor, herein called a kicker, is provided for that purpose, but the motor which normally actuates the control valve may also accomplish such result. The latter may also be provided with means to control the rate of movement of that part of it which is subject to suction; specifically, the suction connection from the engine intake to the suction motor may be throttled even automatically and inversely to the engine temperature, so that for a cold engine the transition from a rich starting mixture to a normal running mixture, or analogous operation, will take longer than when the engine is warmed.

In the disclosed embodiment of the invention a bimetallic thermostat, which forms a yielding operating connection between the suction motor for operating the mixture control and the choke valve, is shown, but there may be employed instead, arigid, or bellows type of thermostat with a spring adjusted by the expansion and contraction of the thermostat. ing the kicker directly to the choke valve, there may be some form of indirect connection and it is also within the scope of the invention to provide a separate choke, operable by the kicker, which is not controlled by temperature or suction.

In the embodiment of the invention illustrated herein the choke valve, which is operable to control the fuel air ratio, is an unbalanced air valve which tends to open as the result of the suction which is directly effective on the valve itself. This is desirable for the reason that there is a great difference in the speeds of operation of the engine as between cranking and operating under its own power. The ordinary cranking speeds are from 20 to 60 R. P. M. whereas the ordinary idling speed is around 200 R. P. M. The sudden increase in suction, which occurs when the engine starts to run under its own power, is effective on the fuel supply nozzle and, if provision were not made to the contrary, might draw in fuel too rapidly. The suction effective on the choke valve operating piston is also increased by the increase in engine speed and this would tend to open such valve, but for reasons which will be apparent later, operation of the valve by the piston is relatively slow and it is desirable to employ an unbalanced valve which tends to open relatively quickly upon increase in the suction directly effective on the valve itself when the engine first becomes self-operative.

One great advantage of the illustrated embodiment of the invention is that it is applicable to almost any carburetor as now constructed, either of the plain tube type, air valve type, or any other type, without any material structural change of either our device or the carburetor. By control of only one member, such as the choke valve, an auxiliary air valve or a fuel valve, all the advantages of the control apparatus which embodies the invention, may be obtained.

Now in order to acquaint those skilled in the art with the manner of constructing, operating and practicing our invention, we shall describe, in connection with the accompanying drawings, a specific embodiment of the same, its mode of use, and the performance of the herein claimed apparatus.

In the drawings:

Figure 1 illustrates one way in which the new appa- Also, instead of connectratus of this invention may be mounted on an automobile engine, showing the parts in the position they assume when the engine is cold;

Figure 2 is a plan view of an embodiment of this invention;

Figure 3 is a vertical section thereof as seen along the line 3-3 of Figure 2;

Figure 4 is a vertical section thereof as seen along the line 44 of Figure 2;

Figure 5 is a transverse section thereof as seen along the line 55 of Figure 4;

Figure 6 is a transverse section thereof as seen along the line 6-6 of Figure 4;

Figure 7 is a section similar to Fig. 3 showing another embodiment of this invention; and

Fig. 8 is a diagram of an illustrative embodiment of this invention.

In Figs. 1 and 8 the invention is shown diagrammatically as applied to a conventional form of carburetor 15 connected to the intake manifold 12 in the usual way. The carburetor 15, which is of the updraft type, has a .mixing chamber A, the outlet of which is governed by a conventional butterfly throttle valve B. This throttle is controlled manually by the operator to control the speed of the engine by controlling the quantity of combustible mixture supplied thereto. A venturi tube C'surrounds the upper end of a main fuel supply nozzle D to which fuel is supplied from a conventional float chamber F. Admission of air to the carburetor, through the air intake connection G, is controlled by a choke valve 14 which is eccentrically pivoted and is, therefore,unbalanced so that the flow of air into the carburetor which is effected by engine suction, tends to open the valve. The float chamber F communicates directly with a well E which is connected directly with the main fuel nozzle D and a conduit H, the lower end of which extends into the well, connects at its upper end with the carburetor intake passage at a point adjacent and posterior to the throttle to supply fuel for idling in the usual manner. The specific construction of the carburetor forms, per se, no part of the present invention and is illustrated merely for the purpose of facilitating understanding of the mixture control mechanism which constitutes such invention.

Referring to Figs. 3 and 8, the choke valve 14 is connected through a crank or arm 13' and a link 13 to one end of a coiled bimetallic thermostat K which is subect to the temperature conditions of the engine and the other end of that thermostat is connected to a rotatable shaft to which is secured a lever 21 connected by a rod 31 to the piston 32 of the suction motor I. Thissuction motor has a cylinder 33 in which piston 32 slides and the cylinder is connected by a tube 11 to the intake manifold 12, posterior to the throttle, so as to be subect to the vacuum maintained in the engine intake between the throttle and the engine. The connection from the manifold to the suction motor I is controlled or governed by valve L which, in this embodiment, is a thermally responsive member subject to the variable temperature conditions of the engine. The choke valve 14 is also connected by the crank 13', link 13 and link 56 to the piston of a kicker device I and the piston is movable in response to variations in suction maintained 1n the engine intake between the throttle and the engine in a manner more fully described later.

Referring to Fig. l of the drawings, the numeral 10 designates the control apparatus of this invention mounted on an automobile engine in such a way that it is subected to the temperature and vacuum conditions of the engine. As already indicated, a suction conduit 11 connects the apparatus 10 with the intake manifold 12 of the engine in order to subject a movable part of .such apparatus to the vacuum maintained in such manifold and such movable part is connected by an operating rod 13 with the biased and unbalanced choke valve 14 or the carburetor 15 of such engine.

The apparatus 10 includes a housing 16 which may be formed of cast metal and having ears 17 at its lower end for securing the apparatus to a part, the temperature of which increases in accordance with the temperature of the engine, such as the conventional hot spot" which is a part of the exhaust manifold that surrounds a part of the engine intake to heat the in-going mixture and through which the exhaust gases pass. However, the apparatus 10 may be secured to any other part of the engine, the temperature of which is quickly raised by a rise in engine temperature so as to correspond to the temperature of the piston heads or cylinder walls.

Referring to Figs. 1-6 and 8, there is journalled in the housing a, the shaft 18, to which is secured one end of a spiral bimetallic thermostat 19 having the pin at its other or free end to which is connected the connecting rod 13, which in turn, through crank or arm 13 is connected to the choke valve 14 of the carburetor 15. The thermostat when coiled thrusts down on rod 13. The thermostat constitutes a yielding spring, which is an important feature. Secured on the shaft 18 so as to rotate therewith is a double armed lever 21, the angular movement of one arm 22 of which is limited in both directions by the upper stud 23 and the lower stud 24, which are mounted for axial adjustment in the housing 16. By withdrawing or advancing either stud 23 or 24, the limit of movement of the arm 22 of the lever 21 may be varied at will. A sleeve 24 threaded into the housing 16 contains the threaded rod 25 which is adjustable lengthwise within the sleeve 24 by means of the nut 26 and lock nut 26'. One end of this threaded rod 25 carries one end of the coil tension spring 27 and the other end of this spring is connected to the arm 22 of the lever 21. This spring urges the arm 22 in a clockwise direction toward the stud 23 as seen in Figure 3, so that the carburetor choke valve 14 is normally urged toward closed position through the connections between it and the lever 21, these connections including the shaft 18, the thermostat 19, the pin 20, the rod 13 and the crank 13'. When the automobile engine is cold the thermostat 19, the lever 21 and the choke valve 14 assume the position shown in Figures 1 and 3, with the arm 22 of the lever 21 engaging the stud 23.

Aside from the other parts later to be described, this provides a thermostatic control of the choke or anterior throttle 14, so that the degree of choking by valve 14 is dependent inversely upon the temperature to which thermostat 19 is subjected. This thermostat is subject tothe temperature of the engine, because of the fact that it is subject to the heat of the exhaust gases leaving the engine. Accordingly, when the engine is cold, the thermostat will be cold and exerts a force tending to hold the choke valve 14 closed. When the engine is running and the temperature thereof increases, this force is gradually reduced until at some predetermined temperature the thermostat will no longer exert a closing force on the valve. After the temperature of the engine reaches such predetermined temperature and increases to normal operating temperature, the thermostat, being directly connected to the valve, will exert a force tending to open such valve.

The other arm 28 of the lever 21 carries a pin 29, which is connected to the clevis 30 of the connecting rod 31 of the piston 32 which is slidably mounted in a cylinder 33 of a suction motor, formed in a block 33' suitably secured in the housing 16. Generally stated, the cylinder 33 of the motor I is suction-connected by the tube 11 to the intake manifold 12 and the piston 32 forms a movable member or wall whose movement responds to variations in the pressure or suction in the manifold. In the embodiment illustrated in Figure 3, the upper end of cylinder 33 is connected by passage 34 to the upper end of cylinder 35, also suitably mounted in the housing 16 and connected by the tube 11 to the intake manifold 12. A check valve 36 is urged to closed position by a spring 37 and normally closes the passage 34 between the cylinders 33 and 35. This check valve 36 and its spring 37 are preferably mounted in a plug 38 threaded into the head of the cylinder 33 as shown in Figure 3. This check valve prevents the immediate return of piston 32 in case of stalling of the engine or sudden drop in suction.

In the particular embodiment illustrated in Figure 3, means is provided for controlling the effect of suction from the manifold 12 on piston or wall 32. To that end the cylinder is preferably formed of a material having a relatively high coefficient of thermal expansion, such as brass, and contains a plug 39 of material having a relatively low coefficient of expansion, such as Invar.

This plug 39 is held by the threaded closure member 40 in the cylinder 35 and a passage 41 extends through the plug 39 and the member 40 so as to communicate with an elbow 42 threaded in the member 40. The cylinder 35 is, in this embodiment, in direct thermal conductive contact with the exhaust manifold or the hot spot, since the housing 16 is mounted on the hot spot, Fig. 1 so that it is subject to engine temperature as distinguished from air temperature only. The tube 11, which is shown in Figure l as connected at one end to the intake manifold of the engine, is connected at its other end to the elbow 42. The interior of the cylinder 33 is thus connected to the intake manifold of the engine through the check valve 36, the passage 34, the space between the Invar plug 39 and the wall of the cylinder 35, the passage 41, elbow 42 and tube 11. Therefore as will be more fully explained later, a suction is produced in cylinder 33 which acts on the piston 32 to elevate it in cylder 33. The cylinder 35 and Invar plug 39 constitute a thermostatic restriction or valve, controlling air flow under suction from cylinder 33 to the intake manifold and determining the rate of movement of the piston 32 in response to suction.

The so-called kicker will now be described. As shown especially in Figures 3 and 6, a passage 43 connects the lower end of cylinder 35 with the lower end of cylinder 44 formed in the block 33. Slidably mounted in the cylinder 44, but normally urged upwardly therein by the spring 45 is a piston 46, as is shown in Figure 4. Spring 45 is seated at its lower end in the plug 47 closing the lower end of the cylinder 44. A relief passage 48 connects the upper end of cylinder 44 with a chamber 49 closed by plug 52 having a passage 51 connecting with the atmosphere. This passage 51 is normally closed by a check valve 50 mounted in the chamber 49 and urged to closed position by spring 49. Thus, when the check valve 50 is unseated, the interior of cylinder 44 communicates with the open air through the passages 48 and 51. Air can be drawn in past the valve 50 by descent of piston 46 but cannot be expelled on upward movement of the piston, as the valve automatically closes.

Connected with the interior of cylinder 44 through the relief valve chamber 49 and passage 53 is a fourth cylinder 54, also formed in block 33, and having the piston 55 slidably mounted therein. A rod 56 which is connected to the piston 55 is also connected by clevis 57 to the pin 20 carried on the free end of thermostat 19, as is shown especially in Figures 3 and 4. The pistons 46 and 55 with their cylinders 44 and 54 and immediately associated parts constitute a suction controlled motor for automatically closing the choke valve 14 upon stopping of the engine. The valve 14 is held closed by the pneumatic motor above described against the spring tension of the thermostat for a time dependent in part upon the rate of leakage of air past the pistons 46 and 55 and in part upon the yielding resistance of the thermostat 19.

Whenever the engine crankshaft is rotated, either when the engine is cranked for starting, or is operating under its own power, the suction maintained posterior to the engine throttle is communicated to the apparatus 10 and more particularly to the piston 32. When the automobile engine is cold the arm 22 of the double armed lever 21 is held against stud 23 by the spring 27 whose tension is properly adjusted by rod 25 and nut 26, whereby the choke valve 14 is held in closed position by'the connections between it and the lever 21 through the thermostat spring 19. Inasmuch as the engine is cold, the thermostatic retarder comprising the Invar plug 39 and the brass cylinder 35 is substantially closed, i. e., the brass cylinder 35 is contracted so that there is an extremely small annular space between it and the Invar plug 39. The thermostat 19 is also contracted and it thereby tends to thrust downwardly on rod 13 in a direction to hold the valve 14 closed.

During the first starting step as the engine is rotated relatively slowly by the starting motor (usually about 30 to 60 R. P. M.) the relatively small degree of suction created in the intake manifold by the slow motion of the engine pistons in their cylinders is communicated to the tube 11, elbow 42 of the apparatus 10, passage 41 and lower end of cylinder 35, of the suction motor. However, because of the small annular space between the Invar plug 39 and the cylinder 35, much of the effect of the negative pressure is lost between the lower end of the cylinder 35 and the cylinder 33, so that although the check valve 36 is unseated and the piston 32 begins to move slowly, its movement is not very great and because of the flexibility of the thermostatic coil 19, the movement of the piston is ordinarily not imparted to the choke valve 14, which thus remains closed or substantially closed during cranking. Accordingly a rich mixture is supplied to the engine cylinders.

However, as the engine begins to fire during the second step or condition, previously referred to, and the engine rotates more rapidly, idling speed of an engine being usually around 200 R. P. M., the suction maintained in the manifold is much greater than during cranking and this greater suction acts through the retarder 3539 to a greater degree, so that the piston 32 rises more rapidly, to initially lean out the mixture, ultimately reaching its extreme upper position. The upward movement of piston 32, when the engine is running, is enough to rotate lever 21. in a counter-clockwise direction as seen in Fig. 3, against the tension of spring 27, until arm 22 engages stud 24. This stud 24 is adjustable to change the terminal position of piston 32 at will, but the piston, when it reaches its uppermost position, remains there, because suction is effective on the piston as long as the engine is running. A controllable leakage port may be provided if desired to time the descent of the piston 32. Inasmuch as the thermostat 19 is mounted on the shaft 18 of the lever 21, it is moved bodily therewith, and as choke valve 14 is connected to the thermostat 19 by arm 13' and rod 13, the choke valve 14 is slowly and gradually but only partially opened as piston 32 rises, so that the richness of the fuel mixture is gradually decreased by the entry of a relatively small but gradually increasing supply of air passing choke valve 14.

In accordance with this invention, therefore, upon starting of the engine when cold, a rich mixture is supplied to the engine, that mixture is partially leaned out after the engine begins to fire and is further leaned out as the engine becomes warm.

Up to this time neither the retarder 3539 nor the thermostat 19 have responded, because the engine was cold, but during the next, or third step after the engine has begun firing and becomes warm, the brass cylinder 35 of the retarder gradually expands relatively to the Invar rod 39, to gradually increase the annular space between them, but the increased suction imparted to cylinder 33 has no effect if piston 32 has already been moved to its extreme upper position. The upward movement of piston 32 is limited by the engagement of arm 22 of lever 21 with stud 24.

Simultaneously with the response of the retarder 3539 to the rising temperature of the engine, the thermostat 19 responds to the temperature of the engine, by uncoiling to gradually open the choke valve 14 sill wider during the next step or final warming up period. Inasmuch as the thermostat 19 is mounted on the shaft 18 which has been set by the piston 32, the movement of the thermostat 19 is added to the movement initially imparted to the choke valve 14, so that the latter is opened still wider and may be opened to fully open position if the engine is fully heated up to normal operating temperature.

Assuming for the time being that no other changes take place in the operation of the engine, it should now be running smoothly under the proper fuel-air mixture, which has been determined automatically in accordance with the fixed setting of the carburetor as modified by the temperature and manifold suction and modified gradually because of the action of the retarder and the relatively slow response of the thermostat 19. The choke controlling mechanism of this invention then becomes ineffective after it has performed its function during the starting and warming up period, turning control over to the inherent action of the carburetor.

If the engine is shut off or stalls, the suction stops immediately and spring 27 tends to withdraw piston 32 and move choke valve 14 towards closed position. Check valve 36 is closed and such return can proceed only as the air leaks past the piston 32 into the upper part of cylinder 33 as the piston 32 is drawn downwardly by the spring 27. The thermostat 19 contracts slowly as the engine temperature decreases, and as the thermostat contracts it moves the. choke valve 14 still further toward closed position until the latter is completely closed when the engine is cold. If the engine should be restarted while still warm, the choke valve is held initially partially open by the thermostat 19 and is at once further opened upon starting by the suction piston 32, since the retarder 3539 is still partially expanded. The initial degree of opening of the choke valve thus depends on the engine temperature at the time, and the rate of opening depends upon temperature of the engine and the degree of suction produced.

Under the operating conditions just described the cylinders 44 and 54 of the kicker I have responded to the engine suction, but have not been utilized to perform their functions for the reason that their use has not been necessary. However, their action under the operating conditions described will be outlined briefly.

Inasmuch as cylinder 44 is connected to cylinder 35 through the passage 43, as shown in the drawings, a suction is also created therein and this suction draws piston 46 downwardly to the bottom of cylinder 44, spring 45 being compressed accordingly. When the piston 55 in cylinder 54 is moved upwardly, because it is connected to thermostat 19, which expands, and is also moved bodily because of its connection with lever 21, the air trapped in cylinder 54 tends to be displaced partially through passage 53 into the cylinder 44 above the piston 46 and also leaks past piston 55 until an air pressure balance in cylinders 54 and 44 is reached. The purpose of the check valve 50 in cylinder 44 is to let in air when the piston 46 is drawn downwardly by the suction. This prevents piston 55 from being appreciably affected by the suction produced by the downward movement of piston 46.

The sudden opening of the throttle to accelerate the engine speed causes the suction produced in the engine intake to decrease at points posterior to the throttle but to increase at points anterior thereto. Therefore, in the illustrated embodiment, upon opening the throttle for acceleration, the suction in the conduit 11 may drop and if this drop in suction was communicated to the piston 32, it would tend to produce a closing movement of the choke valve. However, in the embodiment shown, see Fig. 3, the check valve 36 prevents any appreciable decrease in suction effective on piston 32. The suction effective directly on the unbalanced choke valve itself is increased on opening of the throttle.

Therefore, when the throttle is opened for acceleration, substantially the only change in the forces exerted by suction on the choke valve through piston 32 and directly on the valve itself, is an increase in the latter. Obviously, therefore, there might be an opening movement of the choke valve whenever the throttle is opened for acceleration unless means are provided to prevent such action.

Any opening of the choke valve, upon acceleration, would cause a leaner mixture to be provided, in fact, even if the choke valve did not open but remained stationary, the mixture would become leaner. Due to increase in suction anterior to the throttle, opening of the latter would cause an increase in the flow of both air and fuel. However, due to inertia, the increase in air How would be much greater immediately following the opening of the throttle than the increase in fuel flow. Obviously, this would produce a temporary leaning of the mixture which might result in unsatisfactory engine operation during acceleration.

In the illustrated embodiment of the invention, see Fig. 4, this difiiculty is eliminated by temporarily moving the choke valve 14 toward closed position to restrict the air supply to the carburetor, which will also temporarily increase the suction effective on the main fuel inlet D and this will produce a rich enough mixture to meet the requirements of the engine for satisfactory acceleration. This is accomplished by the action of the kicker device J. As the suction posterior to the throttle suddenly drops, upon opening of the latter, the suction in cylinder 44 below the piston 46 becomes insufficient to hold the piston down against the force of spring 45 which expands and forces the piston upwardly, thus forcing the air above the piston through passage 53 and into cylinder 54. This creates pressure in the cylinder 54 above the piston 55 and tends to force the latter downward. Since the piston 55 is directly connected to the choke valve 14 through the medium of rods 56, 13 and arm 13, the choke valve is moved toward closed position by the piston to reduce, for a short period, the supply of air flowing into the carburetor.

As the engine accelerates following opening of the throttle, see Figs. 3, 4 and 8, the choke valve 14 and the parts of the kicker device are moved back toward the position they occupied before the acceleration took place. As the engine speed increases, the suction, both above and below the throttle, increases and this increase of suction is effective both on piston 32 and directly on the choke valve itself to move it toward open position. Also, the piston 46 is again pulled down by the increase in suction effective thereon so that the pressure on piston 55 is eliminated and the force of the thermostat which was overcome by a downward movement of the piston can again become effective to move the valve 14 toward the position occupied before acceleration.

The time interval during which the choke valve is moved toward closed position in the manner described is very short, preferably only a few seconds, but is sufficient to enable the carburetor to supply to the engine a mixture rich enough to produce satisfactory engine operation during the acceleration period. This time interval is controlled in part by the force exerted by the thermostat in opposition to the piston 55 and the leakage past the piston. In order to control the duration of this interval, an adjustable leak to permit flow of air past piston 55 may be provided, if desired.

During acceleration, other operating parts of the control apparatus, such as piston 32, lever 21 and shaft 18 make substantially no movement. As already stated, while the suction in the engine intake posterior to the throttle is reduced, the closing of check valve 36 prevents any appreciable reduction in the suction in cylinder 33, such suction remaining substantially the same as it was before acceleration. The downward movement of piston 55 would tend to pull piston 32 down through the medium of the thermostat, but, due to the closing of the check valve, there would be substantially no movement during the brief interval the piston 55 is effective.

It will be apparent from the foregoing that in the embodiments of this invention shown and described herein, a carburetor connected to the inlet of the intake manifold 12 has a mixing chamber A, a manually operated throttle valve B, air and fuel inlets G and D to the chamber, and valve 14, or its equivalent, adapted to be variously adjusted to control the proportions of air and fuel in the mixture. Mechanism is provided for automatically controlling the richness of the mixture in response to the temperature and vacuum conditions of the engine to lean out the mixture at high temperatures and/or suctions and to enrich the mixture at low temperatures and/or suctions, all in accordance with the requirements of the engine. A thermostat K is connected to the choke valve 14 and is effective at low temperatures to hold the valve closed to provide a rich mixture for starting. A suction motor I connected to the engine intake posterior to the throttle is responsive to the intake suction, and is operatively connected to the valve. This motor is adapted to open the valve in order to lean out the mixture when the engine first starts; and thermostat K, positioned to be heated in accordance with the heat of the engine, is adapted to further lean out the mixture after the engine has started and warms up. The suction motor and the thermostat do not operate independently, but actually operate in synchronism to first lean out the mixture as required during the warm-up period following starting of the engine and to finally lean out the mixture during normal running. The control device 35, 39, (35, 39') governs the rate of operation of the motor I so as to control, even automatically, the setting of the valve, in accordance with the temperature of the engine.

In the illustrated embodiment, the motor J operates upon a decrease in engine suction, as upon acceleration of the engine, to modify the setting of the valve 12, as positioned by motor I and the thermostat, so as to richen the mixture and the resilient thermostat facilitates the action. The suction motors are responsive to variations in such factors as engine speed, load and throttle position, and operate to vary the effectiveness of the thermostat on the choke valve in accordance with variations in such factors. The resilient thermostat, through which the piston 32 of the suction motor I is connected to valve 14, permits movement of the piston without moving the valve. The stop 23 may be adjusted to determine the temperature at which the valve 14 will be closed, see Figs. 1 and 3, but this valve will be moved to fully opened condition when the normal operating temperature of the engine is reached or exceeded. The valve 14 itself is responsive to the effect of air flow by reason of its eccentric mounting so that upon increase of suction, the air flow against the valve will tend to open it, while the thermostat yieldingly urges the valve toward closed position with a greater force at low than at high with the valve is a spring, the thermostat can continue to move after movement of the valve has been arrested. The temperature and suction-responsive devices are so constructed and connected that the valve is positioned in accordance with an equilibrium established by the forces exerted by these devices on the valve.

It will be seen that the apparatus of this invention automatically responds to all operating conditions encountered during the starting and warming up periods of the engine, regardless of climatic conditions, and entirely eliminates the human factor. Regardless of whether the engine is started during extremely cold weather, from a cold condition, or during warm weather, or is restarted during extremely cold weather from a slightly warmer condition, the various devices which secure the operation of the apparatus respond accordingly to obtain and maintain the proper fuel-air ratio during the starting and warming up periods. Thus, if the engine is started in extremely cold weather, the choke valve opens very slowly because of the resistance of thermostat 19 and the practically closed condition of the retarder 35-39. The engine is thereby provided with a richer mixture which remains rich for a longer time at low temperatures than at higher temperatures to enable the engine to start and warm up properly. During warm weather, or when the engine is initially warm, the retarder 35--39 would permit 21 more rapid opening of the choke valve 14 and the thermostat 19 would respond sooner and more rapidly to add its movement to the movement imparted to the choke valve 14 by the piston 32. It will accordingly be seen that the apparatus of this invention automatically takes care of variable temperature conditions which are encountered during starting and warming up of an automobile engine.

Instead of forming the retarder integrally with the other parts of the aparatus in housing 16, it may be mounted separately as a separate unit on the exhaust manifold or the hot spot of the engine, as is shown in Figure 7. In this arrangement two suction connections between the apparatus and the intake manifold are provided, one suction connection 11' leading to the separate retarder 3539' having the ears 58 for mounting it separately in the manner described, on a part of the engine which quickly rises in temperature when firing begins, and the other suction connection 11' leading from the intake manifold to the chamber 59 which communicates through the passage 43 with the cylinder 44 in the manner described in connection with the preceding figures of the drawings. In this arrangement the retarder 35'--39' responds more quickly to changes in engine temperature, inasmuch as it 15 directly connected to a hot part of the engine, such as the exhaust manifold, the hot spot, or some other part which is immediately subjected to changes in the temperature of the engine.

In the operation of starting the engine when cold, the amount of fuel drawn from the nozzle D must be far in excess of the amount of fuel required by the engine when running, under any operating conditions, .in order to insure successful starting. A mixture having a suitable fuel-toarr ratio for starting a cold engine cannot be produced by a direct proportioning of fuel by weight to air by we1ght, for the reason that the air is moving through the engine intake and manifold at such low velocities and at such slightly negative pressures that it will not atomize the fuel sufficiently to carry it along into the combustion chambers of the engine. Also, at low temperatures only the highly volatile constituents of the fuel will vaporize and the remainder is relatively inert. T here fore, 1t is necessary, for cold starting, to introduce into the intake passage leading to the engine sufficient fuel to form a mixture many times richer than any required running mixture to get a sufficient quantity of ignitible mixture into the combustion chambers to fire and satisfactorily start the engine.

It should be noted that the piston 55 of the kicker device I is directly responsive to a drop in engine suction posterior to the throttle B, which suction is communicated directly to cylinder 44 through passage 43, so that such piston will move downwardly simultaneously with any drop in suction which occurs. The piston 32 of the valve opening suction motor I is, however, controlled by variations in two factors, namely, suction in the engine intake and the temperature of the engine which controls the action of the retarder L. Therefore, the rate of opening of the valve by piston 32 will vary with engine temperature and the valve will open more slowly at progresslvely decreasing temperatures. The kicker J may have a sufficiently stiff spring 49' to permit the sudden descent of piston 46, when the engine starts to fire, or otherwise suddenly increase its suction, to draw up the piston 55, thereby tending to kick the valve 14 temporarily toward open position.

The kicker spring 45 may be so selected or adjusted as to be responsive, not to the vacuum of the engine while it is being cranked, but only to such vacuum as corresponds to firing of the engine.

In the illustrated embodiment, the thermostat 35, 39 or 35, 39 is responsive to exhaust manifold or hot spot temperature and this is generally comparable to the temperature of the walls of the intake pipe of the intake manifold. Likewise, the thermostat 19, in the illustrated embodiment, is also responsive to the exhaust manifold or hot spot temperature, which is generally comparable to the temperature of air passing through a heater WhlCh surrounds the exhaust manifold, as in applicants U. S. Patent 1,701,779, February 12, 1929. Obviously, the thermostat may be positioned in the air intake of the carburetor, with the air entering the carburetor heated by the exhaust gases, as in applicants said patent, so that the thermostat responds to the engine temperature.

While, in the embodiment of the invention herein disclosed, an unbalanced air valve is employed to control the mixture proportions and such a valve is desirable, the invention is in no sense limited to this particular construction and, in fact, various modifications of the invention would be apparent to those skilled in the art, so that the invention is not limited with respect to any structural details except as defined in the appended claims.

What is claimed is as follows:

1. In an internal combustion engine having an intake and a carburetor having an air valve, the combination of means responsive to intake pressure for setting said valve, and means responsive to acceleration of the engine and movable with respect to said first named means for varying the setting of said valve produced by the first-named means.

2. In an internal combustion engine having an intake and a carburetor having an air valve, the combination of means responsive to the temperature of the engine for setting said valve, and means responsive to acceleration of the engine for varying the setting of said valve produced by said first-named means, said last named means comprising a member movable to biased position by intake pressure independently of the position of said air valve.

3. In an internal combustion engine having an intake and a carburetor having an air valve, the combination of means jointly responsive to the intake pressure and the engine temperature for setting the valve, and means responsive to acceleration of the engine for varying the valve toward open position, and independent means responsive to a decrease in the normal intake suction for varying the setting of said valve toward closed position.

5. In an internal combustion engine having an intake and a carburetor having an air valve, the combination of pressure responsive means for controlling the valve, pressure connections between said means and the engine intake, and thermostatic means for varying said connections to alter the operation of said means.

'6. In an internal combustion engine having an intake and a carburetor having an air valve, the combination of means responsive to normal intake suction for moving the valve toward open position, means responsive to the temperature of the engine for retarding the movement of the first-named means, and independent means responsive to a decrease in the normal intake suction for actuating the valve.

7. In an internal combustion engine having an intake and a carburetor having a choke valve, the combination of pressure responsive means for controlling the valve, pressure connections between said means and the engine intake, thermostatic means for varying said connections to alter the operation of said means, and an independent thermostat for varying the setting of the valve produced by said means.

8. In an internal combustion engine having an intake and a carburetor valve, the combination of means responsive to the normal intake suction for initially setting the valve, means responsive to temperature for varying the action of said means, independent means responsive to temperature for varying the valve setting produced by the first-named means, and means responsive to acceleration of the engine for varying the setting of the valve produced by said first and third means.

9. In an internal combustion engine having a carburetor and a valve therefor, means responsive to an increase in the intake suction for controlling the position of said valve, and means responsive to a sudden decrease in the normal intake suction for temporarily removing said valve from the control of said first named means.

10. In an internal combustion engine having a carburetor and a valve therefor, means for shifting said valve to a given position dependent upon normal running conditions of the engine, means separate from said first means and responsive to acceleration of the engine for moving the carburetor valve from said given position, and means for restoring the carburetor valve to said given position after an interval of time.

11. In combination, an internal combustion engine having an intake pipe, a carburetor therefor, said carburetor having a mixing chamber, air supply means and fuel supply means leading to said chamber, means to control the air flow into said chamber for the purpose of controlling the relation between air flow and fuel flow in said chamber, said means constituting a valve, thermostatic means for governing the setting of said valve according to the temperature of a part of the engine, a suction operated motor for changing the setting of said valve towards a position which will produce a leaner mixture, and means other than said thermostatic means for controlling the rate of operation of said motor according to the temperature of a part of the engine.

12. In combination, an internal combustion engine having an intake pipe, a carburetor therefor, said carburetor having a mixing chamber, air supply means and fuel supply means leading to said chamber, means to control the air flow into said chamber for the purpose of controlling the relation between air flow and fuel flow in said chamber, said means constituting a valve, thermostatic means for governing the setting of said valve according to the temperature of a part of the engine, a suction operated motor for changing the setting of said valve towards a position which will produce a leaner mixture, and means separate from said suction operated motor for temporarily moving the valve towards a position which will produce a richer mixture upon decrease of suction in the intake pipe.

13. In combination, an intake pipe, a carburetor connected thereto, an air valve for said carburetor, a pneumatic motor actuated by suction in the intake pipe adapted to initially lean out the mixture when the engine starts to run under its own power, and a yielding thermostat responsive to the temperature of the engine forming a connection between said motor and said valve also adapted to lean out the mixture as the engine temperature increases when the engine is self-operative.

14. In an internal combustion engine having a carburetor and an air valve therefor, means actuated by the intake suction and operative by the continuance thereof to move said valve toward a given position, and means separate from said suction actuated means and responsive to acceleration of the engine for exerting an independent force on said valve to shift the same temporarily to a different position.

15. In an internal combustion engine having a carburetor and an air valve therefor, means actuated by the intake suction and operative by the continuance thereof to move said valve toward a given position, means dependent upon engine temperature for determining the rate at which the valve is moved, and means also dependent upon engine temperature for determining the extent of said movement.

16. In an internal combustion engine having a carburetor and an air valve therefor, thermostatic means connected with the valve for setting the position thereof for starting, means operative between definite limits by intake suction to shift said setting a given amount after the engine starts, and means to determine the rate at which said valve setting is shifted by said suction operated means.

17. In an internal combustion engine having an intake conduit, a carburetor for supplying a mixture of fuel and air thereto having an air inlet and an air valve therefor, thermostatic means connected with said valve and biasing the latter for movement toward a position dependent upon the temperature of the engine, a movable member against which said thermostatic means reacts in establishing said bias, and means responsive to intake suction upon starting of the engine for shifting said member while providing for the continued control of the valve by said thermostatic means, said thermostatic and suctionaesponsive means being constructed and connected to lean out the mixture at high temperatures and/or suctions and to enrich said mixture at low temperatures and/or suctions.

18. In an internal combustion engine having an intake conduit, a carburetor for supplying a mixture of fuel and air thereto having an air inlet and an air valve therefor, thermostatic means connected with said valve and biasing the latter for movement toward a position dependent upon the temperature of the engine, a movable member against which said thermostatic means reacts in establishing said bias, and means responsive to continuation of intake suction for a given time interval for shifting said member from one position to another during said interval while providing for the continued control of the valve by said thermostatic means, said thermostatic and suction-responsive means being constructed and connected to lean out the mixture at high temperatures and/or suctions, and to enrich said mixture at low temperatures and/or suctions.

19. In an internal combustion engine having an intake conduit, a carburetor for supplying a mixture of fuel and air thereto having an air inlet and an air valve therefor, thermostatic means connected with said valve and biasing the latter for movement toward a position dependent upon the temperature of the engine, a movable member against which said thermostatic means reacts in establishing said bias, means responsive to continuation of intake suction for a given time interval for shifting said member from one position to another during said interval while providing for the continued control of the valve by said thermostatic means, and means for adjustably fixing the length of said time interval, said thermostatic and suction-responsive means being constructed and connected to lean out the mixture at high temperatures and/or suctions, and to enrich said mixture at low temperatures and/or suctions.

20. In an internal combustion engine having an intake conduit, a carburetor for supplying a mixture of fuel and air thereto having an air inlet and an air valve therefor, thermostatic means connected with said valve and biasing the latter for movement toward a position dependent upon the temperature of the engine, a movable member against which said thermostatic means reacts in establlshing said bias, and means responsive to the suction due to cranking of the engine to start the same for shifting said member while providing for the continued control of the valve by said thermostatic means, said thermostatic and suction-responsive means being constructed and connected to lean out the mixture at high temperatures and/or suctions and to enrich said mixture at low temperatures and/ or suctions.

21. In an internal combustion engine having an intake conduit, a carburetor for supplying a mixture of fuel and air thereto having an air inlet and an air valve therefor, thermostatic means connected with said valve and biasing the latter for movement toward a position dependent upon the temperature of the engine, a movable member against which said thermostatic means reacts in establishing said bias, means responsive to the suction due to cranking of the engine to start the same, and means for retarding the return of said member upon discontinuance of cranking the engine, said thermostatic and suction-responsive means being constructed and connected to lean out the mixture at high temperatures and/or suctions and to enrich said mixture at low temperatures and/or suctions.

.22. In an internal combustion engine having an intake conduit, a carburetor for supplying a mixture of fuel and air thereto having an air inlet and an air valve therefor, thermostatic means connected with said valve and biasing the latter for movement toward a position dependent upon the temperature of the engine, a movable member against which said thermostatic means reacts in establishing said bias, means responsive to continuation of intake suction for a given time interval for shifting said member from one position to another during said interval, and means for restricting the return of said member to its first position upon the discontinuance of said intake suction, said thermostatic and suction-responsive means being constructed and connected to lean out the mixture at high temperatures and/or suctions and to enrich said mixture at low temperatures and/ or suctions.

23. In an internal combustion engine having an intake conduit, a carburetor for supplying a mixture of fuel and air thereto having an air inlet and an air valve therefor, a spring thermostat connected with said valve and biasing the latter for movement toward a position dependent upon the temperature of the engine, and means responsive to a drop in intake suction for imparting an independent force to said valve to supplant the control thereof effected by said thermostat to temporarily move the valve toward closed position, said thermostatic and suctionresponsive means being constructed and connected to lean out the mixture at high temperatures and/or suctions and to enrich said mixture at low temperatures and/or suctions.

24. In an internal combustion engine having an intake conduit, a carburetor for supplying a mixture of fuel and air thereto having an air inlet and an air valve therefor, a spring thermostat connected with said valve and biasing the latter for movement toward a position dependent upon the temperature of the engine, means responsive to a drop in intake suction for imparting an independent force to said valve to supplant the control thereof effected by said thermostat to temporarily move the valve toward closed position, and means for restoring control of the valve to said thermostat immediately upon the reestablishment of suction in the intake of the engine, said thermostatic and suction-responsive means being constructed and connected to lean out the mixture at high temperatures and/ or suctions and to enrich said mixture at low temperatures and/or suctions.

25. In an internal combustion engine having an intake conduit, a carburetor for supplying a mixture of fuel and air thereto having an air inlet and an air valve therefor, a thermostat connected with said valve and biasing the latter for movement toward a position dependent upon the temperature of the engine, and means responsive to a drop in intake suction for imparting an independent and substantially constant force to said valve to supplant the control thereof effected by said thermostat to temporarily move the valve toward closed position, said thermostatic and suction-responsive means being constructed and connected to lean out the mixture at high temperatures and/or suctions and to enrich said mixture at low temperatures and/or suctions.

26. In an internal combustion engine having a carburetor and an air valve therefor, a spring thermostat connected with said valve and biasing the latter for movement toward a position dependent upon the temperature thereof, means shiftable into a biased position by the intake suction and held in that position during the continuance thereof, and means connecting said biased means with the air valve whereby when the biased means is released .by a drop in suction, said biased means acts through said connecting means to impart a substantially constant force to the air valve to supplant the control thereof effected by said thermostat to temporarily shift the valve toward its closed position against the tension of the thermostat.

27. In an internal combustion engine having a carburetor and an air valve therefor, a spring thermostat connected with said valve and biasing the latter for movement toward a position dependent upon the temperature thereof, means shiftable into a biased position by the intake suction and held in that position during the continuance thereof, and means connecting said biased means with the air valve whereby when the biased means is released by a drop in suction, said biased means acts through said connecting means to impart a substantially constant force to the air valve operative at the lower temperatures to supplant the control of the valve by the thermostat by overcoming the tension of the latter and shifting the valve toward its closed position, the magnitude of said force being inadequate at the higher temperatures to overcome the tension in said thermostat.

28. In an internal combustion engine, means forming a mixing conduit, a throttle for controlling the mixture discharged from said conduit, a choke for controlling the admission of air to said conduit, means for partially closing said choke in response to an opening movement of said throttle when the temperature is low, thereby giving a richer mixture for acceleration, and heat responsive means for preventing such partial closing of the choke when the temperature is high.

29. In combination with an internal combustion engine having an intake manifold, a carburetor having a throttle and a choke valve, temperature responsive means influencing the movements of said valve and operative to move said valve toward open position when hot, and suction operated means capable of moving the valve to at least a partially opened position, said suction operated means comprising a chamber having a fluid connection with the intake manifold at a point posterior to the throttle and having a movable spring pressed wall subject to the suction at said point, said choke valve being moved to fully open position when the normal operating temperature is reached or exceeded and remaining in such fully open position as long as said normal operating temperature is maintained or exceeded regardless of suction.

30. The combination with an internal combustion engine, a carburetor having a choke, temperature responsive means yieldingly urging the valve toward closed position, and suction operated means capable of moving the valve to at least a partially opened position when the temperature responsive means tends to hold the choke valve in closed position, said choke valve being moved to fully open position when the normal operating temperature is reached or exceeded and remaining in such fully open position as long as said normal operating temperature is maintained or exceeded regardless of suction.

31. In or for an internal-combustion engine having a control for varying the fuel mixture, the combination of a thermostatic bimetallic element having a part which is movable according to changes of engine temperature, linkage means connecting said movable part for coupling with the fuel mixture control, a pressure-responsive device for operation according to pressure in the induction system of the engine and a lost motion connection operatively connected between said pressureresponsive device and said linkage means.

32. In combination with an internal combustion engine, a carburetor having a choke valve, temperature responsive means yieldingly urging the choke valve toward closed position, and suction operated means capable of moving the valve to a partially opened position while said temperature responsive means urges the choke valve toward closed position, said choke valve being moved to fully open position when the normal operating temperature is reached or exceeded and remaining in such fully open position as long as said normal operating temperature is maintained or exceeded, regardless of suction.

33. In a carburetor, means forming a mixing conduit, said conduit including a main air inlet, a main fuel inlet, and a mixture outlet, a manually operated throttle valve for said conduit, an inlet valve for controlling the flow through one ofsaid inlets to enrich or lean out the fuel mixture discharged by said carburetor, a heat responsive device for controlling said valve in accordance with the temperature to lean out the mixture upon an increase of temperature, said heat responsive device being constructed and arranged to operate said valve only when the temperature is below normal, and means for operating said valve to lean out said mixture upon an increase in suction in the carburetor, said lastnamed means including a suction conduit connected to a point in the mixing conduit posterior to said manually operated valve, and means for temporarily enriching the mixture delivered by said carburetor upon an opening movement of said throttle, regardless of the position of said inlet valve.

34. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet, an air inlet and an air chamber between said inlet and outlet, a manually operable valve between said air chamber and said outlet, means forming a fuel supply conduit, valve means for controlling the richness of the mixture delivered by said carburetor, means responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and suctions and enrich said mixture at low temperatures 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.

35. 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 manifold suction to vary the effectiveness of the temperature-responsive means.

36. 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.

37. In combination with an internal combustion 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.

38. 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 operated means for rendering the first-named means less effective.

39. 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 self-operation of the engine for moving said member in one direction when the pressure increases and in the other direction when the pressure decreases.

40. 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 intake pipe and subject to the suction in the intake pipe for conducting two fluids into the pipe, namely, fuel and air, a single movable valve means for controlling the flow of one of said fluids relative to the other to vary the fuel to air ratio, a vacuum chamber communicating with said intake pipe and having a movable wall which substantially closes the chamber in all positions of the wall and is operatively con nected with said valve means, said chamber being constructed and arranged to urge the wall toward valve closing position by a pressure intermediate the maximum and minimum subatmospheric pressures created in saidintake pipe by the self-operation of the engine, and a thermostat subject to the temperature of the engine for varying the position of said valve.

41. 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-operation of the engine in accordance with variations in engine temperature and also in accordance with variations in pressure in the passage posterior to the throttle.

42. 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 a temperature 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 variations in the manifold vacuum, the eifect 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.

43. 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 tempera ture is low, means connected with the mixing conduit and movable by a pressure intermediate the maximum and minimum subatmospheric pressures created in said conduit during self-operation of the engine, and means connecting the last named means with the second valve.

44. 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, and means associated with the engine for moving said member in one direction when the engine is running and in the other direction when the engine stops.

45. 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 memher and said device and nonresiliently connected to the latter, said movable member being movable between two positions in the first of which it adjusts 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 movable member and acting to maintain said movable member in said first position when the engine is being cranked and in said second position when the engine is running under its own power.

46. 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 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.

47. 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 operatively 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 it in a direction corresponding to opening of the choke valve upon an increase in suction posterior to the throttle.

48. In a carburetor, means forming a mixing conduit, said conduit including an air inlet, a fuel inlet, and a mixture outlet, a throttle controlling said outlet, a valve for controlling the flow through the air inlet to vary the richness of the mixture generated by the carburetor, a temperature responsive device capable of operation independent of suction for influencing the operation of said valve in accordance with the temperature to decrease the mixture richness upon increase of temperature, and means for operating said valve to decrease said richness upon an increase of suction, said last-named means including a suction conduit connected to a point in the mixing conduit posterior to the throttle.

49. 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, a pressure-responsive valve for controlling the flow through said air inlet to vary the richness of the fuel mixture generated by the carburetor, temperature-responsive means for 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 subatmospheric pressures created in the conduit during self-operation of the engine, and an operative connection between said device and the second valve.

In a carburetor, means forming a mixing conduit having an air inlet and a mixture outlet, 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 con nected to a point in the mixing conduit posterior to the manually operated throttle tending to cause opening of the valve upon increase in suction, said temperature and suction responsive devices and valve being so constructed and arranged that the valve closing force of the temperature responsive 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.

51. In a carburetor, a conduit having an air inlet and I a mixture outlet, a throttle controlling the outlet, an unbalanced valve controlling the inlet, a thermostat operatively connected to the valve 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.

52. In a carburetor, means forming a mixing 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 opening of the choke upon increase of suction, and a thermostat operatively connected to said choke.

53. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet for supply ing a combustible mixture to the engine, an air inlet and a mixing chamber between said inlet and outlet, a manually operable throttle for controlling the mixture outlet, means forming a fuel supply conduit, valve means for controlling the richness of the mixture delivered by said carburetor, and mechanism responsive to both heat and suction for operating said valve means to lean out the mixture at high temperatures and/or suctions and enrich said mixture at low temperatures and/or suctions, comprising, a suction motor having a suction connection leading from a point in said mixing conduit posterior to said throttle valve, said motor being connected to operate said mixture controlling valve to initially lean out the mixture when the engine starts to run under its own power, and a thermostat positioned to respond to the temperature of the engine, said thermostat being operative to progressively lean out the mixture as the temperature of the engine progressively increases when the engine is self-operative.

54. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet for supplying combustible mixture to the engine, an air inlet and a mixing chamber between said inlet and outlet, a manually operable throttle for controlling the mixture outlet, means forming a fuel supply conduit, valve means for controlling the richness of the mixture delivered by said carburetor and which is unbalanced so that flow of air into the carburetor tends to open it, and mechanism responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and/or suctions and enrich said mixture at low temperatures and/ or suctions, including a suction motor operating in response to variations in engine suction for operating said unbalanced valve, and a suction connection leading from a point in said mixing conduit posterior to said throttle for communicating the engine suction to said motor.

55. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet for supplying combustible mixture to the engine, an air inlet and a mixing chamber between said inlet and outlet, at manually operable throttle for controlling the mixture outlet, means forming a fuel supply conduit, a valve for controlling the richness of the mixture delivered by said carburetor and which is unbalanced so that flow of air into the carburetor tends to open it, and mechanism responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and/or suctions and enrich said mixture at low temperatures and/or suctions, comprising, a suction motor operating in response to variations in engine suction for actuating said unbalanced valve, a suction connection leading from a point in said mixing conduit posterior to said throttle to communicate the engine suction to said motor, and a thermostat positioned to respond to the temperature of the engine and connected to said unbalanced valve, said thermostat being effective to close the valve when the engine is cold and effective to progressively open the valve as the engine warms up after it becomes self-operative.

56. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet, an air inlet and an air chamber between said inlet and outlet, at manually operable throttle valve for controlling the mixture outlet, means forming a fuel supply conduit, valve means for controlling the richness of the mixture delivered by said carburetor, means responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and/or suctions and enrich said mixture at low temperatures and/or suctions, including a suction motor having a suction connection leading from a point in said mixing conduit posterior to said throttle valve for operating said mixture controlling valve, and means for retarding the movement of said last-named valve so as to initially retard the leaning out of the mixture when the engine is started.

57. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet, an air inlet and an air chamber between said inlet and outlet, a manually operable throttle valve for controlling the mixture outlet, means forming a fuel supply conduit, valve means for controlling the richness of the mixture delivered by said carburetor, means responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and/ or suctions and enrich said mixture at low temperatures and/ or suctions, including a suction motor having a suction connection leading from a point in said mixing conduit posterior to said throttle valve for operating said mixture controlling valve, and means operating upon acceleration of the engine for moving said mixture controlling valve toward closed position to temporarily enrich the mixture.

58. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet, an air inlet and an air chamber between said inlet and outlet, a I

manually operable throttle valve for controlling the mixture outlet, means forming a fuel supply conduit, a valve for controlling the richness of the mixture delivered by said carburetor, and mechanism responsive to both heat and suction for operating said valve means to lean out the mixture at high temperatures and/or suctions and enrich said, mixture at low temperatures and/ or suctions, comprising, a suction motor having a suction connection leading from a point in said mixing conduit posterior to said throttle valve and connected to operate said mixture controlling valve to initially lean out the mixture when the engine starts to run under its own power, a thermostat positioned to respond to the temperature of the engine and adapted to progressively lean out the mixture as the temperature of the engine increases when the engine is self-operative, and means operating upon acceleration of the engine to move said mixture controlling valve toward closed position to temporarily enrich the mixture.

59. In a carburetor, means forming a mixing conduit,

said mixing conduit having a mixture outlet for supplying combustible mixture to the engine, an air inlet and a mix ing chamber between said inlet and outlet, a manually operable throttle for controlling the mixture outlet, means forming a fuel supply conduit, valve means for controlling the richness of the mixture delivered by said carburetor, mechanism responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and/or suctions and enrich said mixture, at low temperatures and/or suctions, comprising, a suction motor operating in response to variations in engine suction for actuating said valve means, a suction connection leading from a point in said mixing conduit posterior to said throttle for communicating the engine suction to said motor, and means for retarding the movement of said valve by said motor at low temperatures, so as to retard the leaning out of the mixture when the engine is started at low temperatures.

60. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet for supplying a combustible mixture to the engine, an air inlet and a mixing chamber between said inlet and outlet, a manually operable throttle for controlling said mixture outlet, means forming a fuel supply conduit, valve means for controlling the richness of the mixture delivered by said carburetor, and mechanism responsive to both heat and suction for operating said valve means to lean out the mixture at high temperatures and/or suctions and enrich said mixture at low temperatures and/ or suctions, comprising, a suction motor having a suction connection leading from a point in said mixing conduit posterior to said first-named valve and connected to operate said mixture controlling valve, said motor being adapted, when the engine starts to run under its own power to initially lean out the mixture, a thermostat positioned to respond to the temperature of the engine, said thermostat being operative to move said valve to further lean out the mixture as the temperature of the engine increases after the engine has started, and means for controlling the rate at which said motor responds to a variation in suction.

61. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet, an air inlet and an air chamber between said inlet and outlet, a manually operable valve between said air chamber and said outlet, means forming a fuel supply conduit, valve means for controlling the richness of the mixture delivered by said carburetor, mechanism responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and suctions and enrich said mixture at low temperatures and suctions, comprising, a suction motor having a suction connection leading from a point in said mixing conduit posterior to said first-named valve for operating said mixture controlling valve, and a thermostat subject to the heat of the engine and operatively connected to the mixture controlling valve, said suction motor being operatively connected to said thermostat, whereby said thermostat forms an operating connection between said movable member and the valve.

62. 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 etfectiveness of the temperature-responsive means, said temperature responsive means being operatively connected to said choke valve, and said suction responsive means being operatively connected to the thermostat, so that the thermostat constitutes an operating link between the suction responsive means and the valve.

63. 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-operation of the engine in accordance with variations in engine temperature and also in accordance with variations in pressure in the passage posterior to the throttle, said biasing means comprising a resilient thermostat subject to engine temperature and connected at one end to said choke valve, and a movable member subject to the pressure of the induction passage posterior to said throttle, connected to the other end of said yielding thermostat, so that movement of said member is communicated to the choke valve through the medium of the thermostat.

64. 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 self-operation of the engine for moving said member in a direction to effect leaning of the mixture upon increase in the degree of subatmospheric pressure maintained in said manifold, and resilient means opposing such movement of said member and operative to move said member in the opposite direction upon decrease of. subatmospheric pressure.

65. 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 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, said last-named means being connected directly to the temperature responsive means so that said temperature responsive means forms an operating link between the air valve and the suction responsive means.

66. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet, an air inlet and an air chamber between said inlet and outlet; a manually operable valve between said air chamber and said outlet; means forming a fuel supply conduit; valve means for controlling the richness of the mixture delivered by said carburetor; mechanism responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and suctions and enrich the mixture at low temperatures and suctions; said mechanism comprising a suction motor having a suction connection leading from a point in said mixing conduit posterior to said first-named valve and a movable wall movable in response to suction and operatively connected to said mixture controlling valve, and a bimetallic thermostat responsive to engine temperature connected with said last-named valve and adapted to close said valve at low temperatures; and yielding means opposing movement of said wall upon increase in suction etfective thereon.

67. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet, an air inlet and an air chamber between said inlet and outlet, a manually operable valve between said air chamber and said outlet, means forming a fuel supply conduit, a valve for controlling the richness of the mixture delivered by said carburetor, mechanism responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and suctions and enrich the mixture at low temperatures and suctions, said mechanism including a suction motor having a suction connection leading from a point in said mixing conduit posterior to said first-named valve for operating said mixture controlling valve and a thermostat responsive: to engine temperature operatively connected to said air valve and tending to close said valve with a force which decreases with increase in the engine temperature, said thermostat being of resilient construction so that movement of the thermostat can continue after movement of the air valve has been arrested.

68. In a carburetor, means forming a mixing conduit, said mixing conduit having a mixture outlet, an air inlet and an air chamber between said inlet and outlet, a manually operable valve between said air chamber and said outlet, means forming a fuel supply conduit, a valve for controlling the richness of the mixture delivered by said carburetor, mechanism responsive to both heat and suction for operating said valve to lean out the mixture at high temperatures and suctions and enrich the mixture at low temperatures and suctions, said mechanism comprising a pair of serially connected units for controlling the position of said mixture controlling valve in accordance with engine temperature and engine suction, one of said units being a thermostat for governing the setting of the valve in accordance with the temperature of a part of the engine and tending to close the valve at low temperatures and the other of said units being a suction motor operative to move the valve toward open position to produce a leaner mixture upon increase of suction and a suction connection leading from a point in said mixing conduit posterior to said first-named valve and connected to said motor.

References Cited in the file of this patent UNITED STATES PATENTS 1,413,985 Hodges Apr. 25, 1922 1,664,718 Williams Apr. 3, 1928 1,723,936 Hifner Aug. 6, 1929 1,799,486 Stokes Apr. 7, 1931 1,811,354 Joeck June 23, 1931 1,841,687 Stokes Jan. 19, 1932 1,842,690 Stokes Ian. 26, 1932 1,887,061 MacMillan Nov. 8, 1932 1,915,851 Ericson June 27, 1933 1,957,289 Purpura May 1, 1934 2,306,251 Henning Dec. 22, 1942 2,309,419 Sisson Ian. 26, 1943 2,365,910 Shaff Dec. 26, 1944 2,421,733 Henning June 3, 1947

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