US2276311A

US2276311A - Automatic choke mechanism

Info

Publication number: US2276311A
Application number: US107480A
Authority: US
Inventors: Clarence H Jorgensen
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1936-10-24
Filing date: 1936-10-24
Publication date: 1942-03-17
Anticipated expiration: 1959-03-17

Description

March 17, 1942.

C. H. JORGENSEN AUTOMATIC cHoKE MECHANISM 2 sheets-sheet 1 Filed Oct. 24, 1936 3m a/wto@ L @RE/VCE h. Janet-NSEM March 17, 1942. c. H. JRGENSEN 2,275,31

AUTOMATIC CHOKE MECHANISM Filed 001'.. 24, 1936 2 Sheets-Sheet 2 E .g Y

Patented Mar. 17', 1942 AUTOMATIC CHOKE MECHANISM Clarence H. Jorgensen, Anderson, Ind., assignor to General Motors Corporation, Detroit. Mich., a corporation o! Delaware 1 Application October 24, 1936, Serial No.'107,480

44 Claims.

The present invention relates to means for controlling automatically, the` ratio of fuel to air in the combustible mixture formed by the carburetor of an internal combustion engine, and more particularly to that type of mixture proportioning means which is controlledjointly by the action of a thermally responsive device and some other means which varies the effect of the thermally responsive device and is operable by engine suction. Structures of this general nature are shown in the prior application, Serial.

No. 585,510, filed January 8, 1932, by C. H. and P. J. Jorgensen, and abandoned application Serial No. 56,605, filed December 30, 1935, by C'. H. Jorgensen, which, in a sense, is .directed to a number of specific improvements on the earlier case. In both of these devices, the mixture ratio is controlled during various operating conditions by the position of an -unbalanced valve in the air inlet of the carburetor functioning to regulate the admission of air thereto and operating to produce a mixture high in fuel content when the valve approaches closed position and a mixture having less fuel content proportionally as the valve moves to a more nearly open position.

In both the earlierapplications referred to the unbalanced valveis held in closed position by a spring which tends to open under the pressure of the incoming air when the engine is rotating and when the engine is cold, a thermostat is also effective to hold the valve in closed position, the thermostat acting to move the valve toward open position as said thermostat expands upon increase of engine temperature. By this means, a rich mixture is provided for cold starting and leaner mixtures for normal running conditions.

Also the eiect of the thermostat on the valve is modiiied by the action of engine suction so that the valve may assume a position as determined by the thermostat and then upon some change of suction.

Also in both of the earlier devices above referred to, means are provided for effecting the admission of air in progressively increasing quantities in the event of prolonged cranking of the engine without starting in order-to prevent flooding under such conditions. Means are also disclosed -in both of the earlier applications which are operable to temporarily move the unbalanced air valve toward its closed position upon opening of the throttle valve in o rder to provide during the acceleration period the richer mixture which', as is well known, is necessary to'weiect satisfactory engine operation during such period.

It is the general broad object of the present invention to provide further 'improvements over the device disclosed in the earlier application, and to provide a structure'of the character described which is effective to so control the proportions of the mixture supplied by the carburetor to therengine that such mixture will be a more nearly perfect one during all conditions of starting and operating than the devices of the earlier applications were effective to supply. It is also a part of the broad objectof this invention to simplify the construction of the control mechanism so that it can be more readily manufactured,rwill be more reliable in its operation,4

and will be less expensive to produce.

More specically, one object of the invention is to more accurately control the leaning of the mixture during cranking spe'clcally with respect to the time required to eect this leaning of the mixture in orderthat ooding may still be prevented, but at the same time the mixture will not be rendered too lean.

It is also an object of the invention to more accurately control the action of the suction operated mechanism which moves the air inlet valve toward open position when the engine starts to run under its own power to prevent too sudden opening of the valve with resulting upsetting ofthe mixture conditions.

A further object of the invention is to provide is connected resiliently 'to a suction operated piston which is slidable to move the ai-r valve toward open position when the engine suction effective thereon increases and which is so constructed that the movement of the suction operated pistonin a direction to open the air valve is retarded by the action of the dash pot to give the proper tlmingof this function to produce the best mix-g, ture proportions when the engine starts, tofruny under its own power and also to so-control the movement of the suction operated piston during. cranking that while iiooding is prevented, the y mixture will not be leaned sufficiently to interfereVK with the starting.

,A further feature of the invention residesl'in n E y the provision of means' operable by the throttle to yieldingly move the suction operated piston toward a position to open the air valve above referred to, upon opening movements of the throttle and this means also has the function of opposing the movement of the suction operated piston in a direction to close the choke valve upon certain opening movements of the throttle accompanied by a reduction in suction for the purpose of accurately controlling the enrichment of the mixture upon acceleration.v

Y A further feature of the invention consists in a very much simplified means of connecting the thermostat so that the thermostat 'is subjected to f a degree of heat more closely approaching the engine temperature than in earlier devices of this general character..

The Various `features above described produce a number 'fwry distinct functional advantages over earlier devices of this character, among which are the following:

1. The time during which the mixture is enriched for starting when cranking with wide open throttle is more accurately controlled.-

2. Too much enrichment of the mixture is prevented when running with sustained wide open throttle.

3. When shifting from cranking to running conditions, the leaning of the mixture is retarded by action of the dash pot so that when the engine starts to run under its own power, stalling is prevented.

4. Additional mixture enrichment is provided temporarily for acceleration and the degree of such enrichment is varied depending upon the speed at which acceleration takes place.

5. Adjustment of both the cranking and running mixture can be effected to compensate for fuels of different volatility.

6. The device is .entirely enclosed, preventing damage by dirt and corrosion and all levers, rods l and the like for transmitting motion to the'valve Fig. 3 of means for attaching the thermostat to the shaft actuated thereby.

Fig. 8 is a. diagrammatic view, part in section and part in elevation, to illustrate the function of the device as a whole.

Referring primarily to Figs. 1 and 8, the reference character I0 indicates the carburetor in its entirety, which is provided with two intake passages I2 and I4, controlled by throttle valves I6 and I8 respectively, on a common shaft 20, while the number 22 indicates a fuel chamber of the conventional type which partly surrounds the intake passages and supplies fuel thereto in any desirable way. The carburetor is of the downdraft type and is attached when in use to the intake manifold indicated at 24, while adjacent the manifold and cas't integral therewith is a chamber 28 through which exhaust gas passes. This may be the exhaust manifold, itself, or may be a chamber connecting therewith comprising what is known in the art as a hot spot. 'I'his chamber supplies the heat which is utilized to heat the thermostat in a manner hereinafter described. 'An operating connection for the throttle shaft of conventional type is provided and a, connection 30 extends from the throttle shaft to an accelerator pump, this mechanism being no part of the present invention. An unbalanced valve 32 is positioned in the air inlet 34 and valve 32 is secured olf center to a shaft 36 which is Journalled for rotation in the walls of the air inlet 84 and is operable by the incoming air, as clearly shown in Fig. 2. This valve obviously regulates the admissionof air to the carburetor and the air flowing past said valve is mixed with fuel and forms the mixture which is supplied by both passages I2 and I4 to the engine.

The shaft 38 tofwhich the unbalanced valve 32 is secured is adapted to be operated by mechanism controlled by a. thermostat and engine suction as previously indicated, such mechanism l being positioned within a housing 38 which is which controls the degree of enrichment of the A mixture have been eliminated.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. l is a side elevation of a dual carburetor having a common air inlet, the air valve in which is controlled by a mechanism constructed in accor-dance with the present invention.

Fig. 2 is a side elevation of the device viewed from the left in Fig. 1.

Fig. 3 is a section on the line 3-3 of Fig. 2

Fig 4 is a horizontal section on the line 4-4 i of Fig. 3.

, Fig. 5 is a vertical section on the line 5-5 of secured to the housing of the carburetor by machine screws, which are indicated at 40, or in any other desirable manner. To enable this mechanism to actuate the valve 32, the shaft 38 is connected in any suitable way to one end of a flexible cable 42 which, as shown in the drawings, projects into a recess 44 formed in one end of the shaft 38 and which is keyed thereto. The other end of the flexible cable projects into a similar recess 46 formed in the upper end of a shaft 48 which is journalled in a sleeve 50 received in the housing 38, as shown in Fig. 3, a bearing 52 being provided in the upper end of the sleeve. At the lower end of the sleeve 50, another sleeve' 54 surrounds shaft 48, being rotatable thereon and journalled in the sleeve 50.

Suitably secured on this sleeve 54 is a gear segl described. Depending from this gear segment is through the regulating mechanism which controls the position of the carburetor inlet air valve.

la pin 58 which is suitably secured to the segment and projects into a slot formed in a, bifurcated member 62, best shown in Fig. 8, which is secured by rivets or in any other desirable way to a thermostatic element 64 in the form of a spiral coil which surrounds the lower portion of the shaft 48 with its lower end secured to the shaft, extending longitudinally of the shaft from the gear segment to the bottom of said shaft.

The means for securing the lower end of the thermostat to the shaft is capable of adjustment to vary the force of the thermostat which tends the shaft 48 passes, while the upper arm 'l0 of the U-'shaped member is bifurcated and receives the shaft between the two forks thereof.' The vertical portion 12 of the U-shaped member has an orifice in which a set screw 'I4 is threaded so that the end of the screw engages a reduced portion 16 of the shaft 48 and may be tightened to secure the member 66 in any desired position with respect to the shaft.

The gear segment 56 is provided with teeth 18 which engage teeth 80 formed on the exterior surface of a piston member 82, received'within a cylinder 84, formed within the housing 38 normally adapted to be held in the position shown in Figs. 5 and 8 by a spring 86, which is received in the cylinder between the end thereof and the piston which is partially hollow to embrace the spring. The piston slides within the cylinder due to the eiect of engine suction and under the lnfluence of other forces, as will be more particularly set forth hereinafter, but when it is held in any given position by the spring 86 or by other means, a change in temperature will cause expansion or contraction of the thermostat and if the piston is stationary at this time, the gear segment 18 is held stationary so that'this expansion or contraction of the thermostat will cause the free end of the thermostat to move and so rotate the shaft as which, through the nexime connection 42 previously described, will move the valve toward open or closed position. expansion of the thermostat due to arise in temperature causing the valve to open and a contraction of the thermostat having the reverse effect and causing the valve to. close.

'I'he suction operated piston hereinbefore referred to, under normal conditions when the engine is not running, is held in position at the left of the cylinder in which it slides by the spring 88. As soon as the engine starts to rotate when it is being turned by the starting motor during the cranking period before the engine starts to run under its own power, suction is communicated to the cylinder in which the piston slides through the passage 88 which connects with a sump or chamber 90 within the housing 38 and this in turn connects witha diagonal passage 92 leading to a horizontal passage 94 terminating at the wall of one of the carburetor intake passages just posterior to the throttle valve I6. as shown in Fig. 1. Through this series of passages and manifold vacuum is communicated to the cylinder 84 to the right of the member 82' as shown in Fig. 5 and any increase in such vacuum tends to move the piston to the right while a decrease in vacuum tends to cause movement of the piston to the left.

The piston 82 is provided with a hollow exten-V sion 96, into which projects `a rod 98, which extends through a closure member |00 secured in position in the end of the extension 98 by a split ring |02, or in any other suitable way. The rod 98 has a reduced portion |04 on which is secured by riveting or otherwise, a circular member or washer |06 which has a loose ilt withinthe hollow extension 98, and a springv |08 is received between this head and the end of the cylinder formed within the hollow extension of the piston 84. 'This spring tends to normally hold the member |08 against the closure member |00, the position shown in Fig. 5.

The gear teeth previously referred to are formed on the external surface of the hollow extension 96. The rod 98 has secured thereto or formed integrally therewithfa flange ||0 which projects therefrom for a purpose to be set forth in greater detailhereinafter and at its other end the rod is connected to a circular member or washer ||2 similar to the element |08 and secured to the rod in the same way. This member 2 loosely fits within a cylinder ||4 formed in a hollow piston ||6 which slides within a cylinder I8 formed in the wall of the housing 38, the piston ||8 and cylinder ||8 gonstituting a dash pot for controlling the movement of the piston 82 in a manner more specifically described hereinafter.

The cylinder ||4 is provided with a closure member |20 held in place by a split ring |22 or in some other suitable way and a. spring |24 is received between the member ||2 and the solid, closed end |28 of the cylinder |4, which is formed integral with the walls thereof, the springs |24 and |08 being of equal strength and tend to hold the rod 98 in the position shown in Fig. 5 unless it is displaced by some other means. Springs |08 and |24 are rather weak springs and lof less strength than the spring 86. A closure member |28 is secured in the housing 38 at the left end of the cylinder ||8.

In order that the resistance to movement ol' the piston ||6 in cylinder 'H8 be varied as the with a closure member |36 having an orifice |38 therein at its outer end.

Cooperating with the flange ||0 is a means by which the movement of the throttle tends to move the rod 98, and through 'the eflect of the rod 98 to variably control the action of the piston 82 and through it the action of the choke valve, in order to more accurately proportion the mixture under different operating conditions. This means comprises'a springarm |40 extending upwardly from themain body of the spring, which is tn the form of a coil |42 surrounding a stub shaft |44 screwedinto the housing 38 and the other end of the coil has a bent-over portion |48 underlying a lever indicated in its entirety by the reference character |48 which is pivoted on the stub shaft |44 and is adapted to be operated by the throttle for the purpose of creating pressure through the spring arm |40 on the flange ||0 in a manner now to be described.

The lever |48 has a horizontal arm |50 carrying a pin |52 on which a roller v|54 is rotatably mounted and this roller is adapted to .be engaged by a. cam |56 which is mounted onfa squared portion of a shaft |58 journalled in a bushing |59 secured in the wall of housing 38. In the end of 'on the valve to hold the latter open or |66 which lies to the right of the spring arm |40 in Figs. 5 and 8. Obviously upon rotation of thethrottle in a direction to depress the aforementioned roller, which is theopening movement of the throttle, the lever |48 is swung on its pivot and the arm |50 thereof presses down on the end |48 of the spring which underlies such lever while the arm |64 is swung to the right out of the path of movement of the spring arm |40 so that the spring is put undertension and the pressure of the spring arm |40 tends to move the rod 98 to the right through the contact of said arm with the fiange I0, while a reverse motion of the throttle shaft which would permit the roller to move upwardly would cause the spring to be moved away from-the flange through the action of end |46 of the spring on the horizontal arm of the lever. This would tend to swing such lever upwardly and the bent-over portion |66 of the lever would tend to pull the spring arm |40 to the left to permit the rod 98 to move to the left under the influence of the spring |06. The actual movements which this rod makes as a result of the actuation of the throttle will be hereinafter more fully described. y

or for any other reason that may be found desirable, the segment has two stops formed thereon numbered and |12 which are adapted to engage with an eccentric member |14 which is carried by a pin |16 extending through anV orifice in the housing 38 and provided at its outer` end with a nut |18, while between the nut and the wall of the housing is a spring washer |80 which presses against the wall of the housing 38 when the nut' |18 is tightened, engaging oriflcesin the wall to act as a detent to hold the eccentric` member |14 in any desired position of adjustment. The nut may be moved and the eccentric member rotated so as to variably limit the movement of the two stops |10 and |12, as such stops are rotated upon lateral movement of thepiston 82. By variably positioning the eccentric member, thedegree of pressure of the thermostat closed would be varied and this will vary the amount of air admitted for any given suction effect on the valve and so to this extent variably controls the mixture proportions for any setting of the eccentric member |14, and this setting of the eccentric member controls the richness of both cranking and running mixtures.

It will be noted that the flexible cable 42 through which the movement of the automatic control unit is transmitted to the choke valveis surrounded by a rubber housing |90 for purposes of protection and to prevent dirt and the like gettingon the flexible cable.

Heat to bring the thermostat up to or toward engine temperature is conveyed to the thermostat through a heater tube |94 which may be closed at the lower end, as shown in the drawings, or open if desired. This lower end of the heater tube fits within a recess |95 formed in a boss |88 on the wall of the exhaust manifold 28 or tends upwardly from the saidrecess and surrounds a large part of the thermostat, forming an efficient means for conducting heat thereto as the engine temperature rises.

An outer tube |91 surrounds the heater tube and fits within an opening in the lower wall of the housing 88. This outer tube extends downwardly to a point adjacent the surface of the boss |98 and serves a double purpose, first. it shields the heater tube from cold air and increases its efliciency and, second, it protects the heater tube, keeping dirt, water, etc. from entering the housing and from contact with the thermostat. j

' Operation The above described mechanism operates substantially linthe following manner. If it be assumed that the engine is at rest and cold, the piston 82 is inl its left-hand-position as shown in Figs- 5 andl 8, having been movedto that position by the cooperative action of the spring 86 and the contraction of the thermostat which tends to move valve 32 toward closed position until the motion of the parts is stopped'by engagement of the stop |12 with the eccentric member |14. With lthe parts stopped in this position, the contracted thermostat holds the valve 32 closed with a force dependent on the temperature, the lower the temperature the greater the force exerted by the thermostat in holding the valve closed. Therefore, when cold and the lengine not in operation, the valve 32 is held closed by the thermostat with a force dependent on the temperature, the maximum force applied being no greater than the strength of spring 86 v in its extended position.

the hot spot as desired. The heater tube ex- 75 Now then assume that the starting motor is caused to become operative to rotate the engine for the purpose of starting said engine, the

latter is turned slowly, creatinga suction or partial vacuum in the intake manifold which is communicated to cylinder 84 to the right of the piston 82, but owing to th'e very slow rate of rotation of the engine, this suction or partial vacuum is in- -suflicient to move the piston 82 to the right against the force exerted by the cooperative action of the spring 86 and thermostat, as previously described. Accordingly, the choke valve 32 is held closed during the cranking period and if the engine fails to start in a given time, ooding would occur unless some'means were provided to prevent such action.

It will be understood that the strength of the spring is greater than that of spring 86 and when such spring isput under tension by movement of the throttle toward wide open position, spring |40 gradually overcomes the force of spring 86 and piston 82 is moved against the pressureof spring 86.

According to the present invention the throttle is utilized to operate mechanism to prevent flooding in the event of prolonged cranking without starting of' the engine. If the engine fails to start, opening of the throttle, through cam |66, will rock the lever |48 in a clockwise direction, increasing the pressure of the spring arm |40 o n the flange ||0 until the rod 98 is moved to the right compressing spring |08 until finally Vthe piston 82 is moved to the right through the sistance as the movement of said piston in that direction progresses, due to the action of the air Ableed hole |30. The throttle may then be returned to the desired position for restarting and the cranking operation continued until the en' gine starts.

In starting it may be that the throttle is opened to some extent simultaneously with the closing of the starting motor circuit. In devices equipped with starting systems operated by the acceleration pedal, such pedal may be moved on beyond the position at which the starter switch is closed to open the throttle wider for starting, all with the same motion of the accelerator pedal. If the mechanism hereindescribed be used on a car in which starting is eifected by operation of the ordinary'manual pedal, the throttle may be opened relatively wide simultaneously with the pedal movement.

If the throttle opening to a relatively wide open position does take place simultaneously with the energizing of the starting motor, the previously described operation to eifectopening of valve 32 begins immediately, but the-parts are so constructed that there is ample delay for starting to be eiected before the valve 32 is opened, to prevent ooding as described. This delay is eifected by the dash pot and there is suflicient delay to enable `proper starting even if the throttle is opened wide during cranking.

When the engine starts to run under its own power, the suction'eifective on the piston 82- greatly increases, as well as the iiow of air through the carburetor which is eiective on the unbalanced valve 32 and these forces are suillcient to overcome the pressure of the spring 86 and the resistance of the dash pot, but the action of the dash pot retards the movement of the-pisl ton 82 and thus prevents too rapid opening movement of the valve 32 or movement of said valve `too far toward open position, in this way preventing the admission of sumcient air to lean the mixture to an undesirable degree when the engine is running under its own power during the warm up period. If, after the engine is operating under its own power, the throttle be opened to accelerate the engine, the spring arm d and the dash pot piston HS cooperate to provide a mixture of proper proportions during such period. It is, of course, desirable that the mixture be enriched during the acceleration period, but it is not desirable that it be enriched suilciently to cause loading. Whenever the throttle is opened for purposes of acceleration, the suction eifective on the piston 82 is reduced and the spring 86 forces the piston toward the left to effect a closing movement of the valve 32. This closing action of the valve 32, particularly the time of such action prior to opening of the valve after its temporary closing is controlled by the dash pot so.as to provide the proper degree of venrichment to get the best results.

With the structure disclosed, if it be assumed that the engine ,is running at low speed with but slightly open throttle, the piston 't2 as well as dash pot piston stands somewhat to the right and the ange Il may stand at a distance from the spring arm |50, or in contact therewith depending on the position of the throttle andthe suction eective at the moment. When the throttle is opened the suction eifective on. the piston 82 immediately drops with the result that the spring 35 moves such piston toward the left to eiect a closing movement of the valve. This movement is only temporary and the whole assembly is moved back toward open position by the action of the spring arm |40. The first action which takes place is the motion of the piston 82 to the'left to eifect a closing movement of the valve as above described. However, the opening movement of the throttle which lbrings about acceleration rotates the cam |56k increasing the force exerted by the spring arm and moving the piston 82 back toward the right after its temporary movement to again open the valve 32. This action of the spring arm is delayed by the dash pot piston, but not to the same degree that the action of the spring arm is delayed when cranking, as previousiy described. This is due to the vfact that' when acceleration takes place, the dash pot piston is not all the way to4 theleft in its cylinder and it takes less time for such piston to be moved to uncover the bleed hole and break the resistance of the dash pot. It is obvious also that the t2 is ineifectivefto close it, or move it toward closed position.

As set forth above, the adjustment of the eccentric member |18 is utilized to determine the pressure exerted by the thermostat in holding the valve 32 in its normal closed position and to limit its opening movement under the inuence of suction by reason of the engagement of the stops |19 and |12 with the eccentric member. This device is used for seasonal adjustment for instance, being so set in warm weather that the thermostatic pressure to hold the valve 32 closed is less than would be the case with a colder weather setting.-

While the embodiment of the `present invention as herein disclosed, constitutes a preferred form, it is Lto be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is 4as follows:

1. In a charge forming device'having a` mixture passage, means for supplying fueland air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture, means for -automatically controlling the proportions'of fuel andair in said mixture, a thermally responsive device. and a device operable by engine suction for variably regulating the position of said means, and resilient means operable by the throttle for controlling the Iaction of said devices.

2. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a .combustible mixture and a throttle for controlling the ilow of said mixture, means `for automatically controlling the proportions 4of\f\u/e1- `and air in said mixture, a thermally responsive device, and a device operable by en- -gine suction for variably regulating the position of 'said means, and resilientv means operable by the throttle for variably regulating we action of said devices in accordance with different throttleture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture, mechanism for automatically controlling the proportions of fuel and air in saidmixture comprising an air valve for regulating the admission of air tothe charge forming device, thermally responsive means for positioning the air valve in accordance with temperature conditions, and resilient means operable by the throttle for modifying the effective force of the thermally responsive means on said air valve.

4. Ina charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture, means for automatically controlling the proportions of fuel and air in said mixture comprising an air valve for regulating the admission of air to the charge forming device, mechanism for 'positioning the lair valve in accordance with ternperature conditions, mechanism for positioning the air valve in accordance with engine suction. and throttle-operable means arranged in series with and eilective through one of said mechanisms for positioning the air Valve to vary the position of said valve in accordance with the position of the throttle.

5. In a charge forming device having a mixture passage, means for supplying fuel andA air thereto to form a combustible mixture and a throttle ior controlling the ilow of said mixture,

' ture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the flow of Asaid mixture,

,mechanism for automatically controlling the proportions of fuel and air in said'mixture comprising an air valve for regulating the admission of air to the Vcharge forming device, thermally responsive means adapted to hold said air valve in a substantially closed position at low temper-atures to enrich the mixture for starting, resilient means operable by the throttle to open said valve during engine cranking and against the pressure of4 the thermally responsive means, and means to delay the opening of said valve by the operathereto to form a combustible mixture and a throttle for controlling the flowy of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for regulating the admission of one of said mixture components, thermally responsive means for holding such valve in position to enrich the mixture at low temperatures, and resilient means operable by the throttle to bring about opening of said valve by varying the force exerted by said thermally responsive means on said valve.

9. In a charge forming device having a mixture passage, means for supplying fuel and air thereto toI form a combustible mixture and a throttle for controlling the-flow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for regulating the admission of one of said mixturecomponents, thermally .responsive means for holding such valve in position to enrich the mixture at low temperatures, resilient means operable by the throttle for moving said valve toward position to lean the mixture, and means to delay the motion of the valve with respect to the movement of the throttle.

10. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the ow of said mixture, mechanism for automatically controlling the proportions of fuel andair in said mixture comprising a valve for regulating the admission of one of said mixture components, thermally responsive means for holding such valve in position to enrich .the mixture at lowlmperatres, means operable by the throttle to bring about opening of -said valve by varying the force exerted by saidV thermally responsive means on said valve, during cranking of the engine, and suction operable means operable when the engine is operating under itsown power to also move said valve to a position to lean the mixture.

11. In a charge forming device having a mixture passage, means for supplyingfuel and air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for regulating the admission of one of said mixture components, thermally responsive tion of said throttle relative to the movement of the throttle.

7. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture,.

silient means operable by the throttle for modifying the effective force Aoi the thermally responsive means on said air valve.

8. In a charge forming device having a mixture passage, means for suppwa-e el and air means for holding such valve in position to enrich the mixture at low temperatures, means operable by the throttle'for moving said valve toward position to lean the mixture during cranking of the engine, suction operable means operable when the engine is operating under its own power to also move said valve to a position to lean the mixture,

and means for retarding the movement of said' valve toward its lean mixture position.

12. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for regulating the admission of one of said mixture components, thermally responsive means for holding such valve in position to enrich the mixture at low temperatures, means operable by the throttle for moving said valve toward position to lean themixture during cranking of the enginasuction operable means operable when the engine is operating under its own power to also move said valve to a position to lean the mixture, and means for retarding the movement of said valve toward its lean mixture position', said means being so constructed as to vary its retarding/eiect in accordance with the position occupied by the valve when its movement toward mixture leaning position begins.

13. In a charge formingdevice having a mixturepassage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the ow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for regulating the admission of one of said mixture components, thermally responsive means for holding such valve in position to enrich the mixture at low temperatures, a suctionoperated member adapted to move the valve toward position to lean the mixture, means operated by the throttle for also moving the valve to lean the mixture and a dash pot connected to said suction operated member to retard the movement of said valve toward its lean mixture position.

14. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the ow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture compris- I ing a valve for regulating the admission of one of said mixture components, thermally responsive means for holding such valve in position to enrich the mixture at low temperatures, a suction operated member adapted to move the valve toward position to lean the mixture, and a dash pot connected to said suction operated member to retard the movement of said valve toward its lean mixture position, said dash pot being so constructed that its retarding effect is variable and depends on the position of the valve vat the time its movement toward mixture leaning position begins.

15. In a charge forming device having a mixture passage, means for supplying fuel and air .thereto to form a combustible mixture and athrottle for controlling the flow of said mixture,

mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for controlling the admission to the charge forming device of one of the components of said mixture, a thermostat for variably positioning said valve in accordancewith temperature conditions, an operating shaft for the valve connected to one end of thethermostat, a driving member connected to the other end of the thermostat, and having gear teeth thereon and a suction operated piston provided with cooperating teeth adapted to engage the teeth on said driving member, whereby engine suction is adapted to operate said valve through the medium of the thermostat.

16. In a charge forming device having `a mixvture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture compris'- ing a valve for controlling the admission to the charge forming device of one of the components of said mixture, a thermostat for variably positioning said valve in accordance with temperature conditions and resilient. means operable by the throttle as it is moved toward open position to bring about a movement of the valve totioning said member, and means operable by the throttle for variably positioning said mixture conward open position by varying the effective force of the thermostat on said valve..

17. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the quantity of said mixture supplied-to the engine, mechanism for automatically controlling the lproportions of fuel and air in said mixture-comprising a member for variably regulating the admission of one of the components of such mixture, means operable by fluid pressure produced by the engine for variably positrolling member, said last named means being effective to move said member through the medium of said fluid pressure operated means.

18. In a charge forming device having a 'mixture passage, means for supplying fuel andair theretoto form a combustible mixture and a throttle for controlling the quantity of said mixture supplied to the engine, mechanism for automatically controlling the proportions of fuel and airY in said mixture comprising a member for variably regulating the admission` of. one of the components of such mixture, thermally responsive means for variably positioning said mixture controlling member and resilientmeans between.

the throttle and the thermally responsive means, said resilient means being operable by the throttle and effective through the medium of the thermally responsive means to move said member.

19. In a charge for-ming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the quantity of said mixture supplied to the engine, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a member for variably regulating the admission of one of the components of such mixture, thermally responsive means for variably positioning said mixture `controlling memb'er, fluid pressure operated means for positioning said member and means operable by the throttle and effective through the medium of said thermally responsive and fluid pressure operated means for variably positioning said member in accordance with different throttle positions.

20. In a charge forming devi-ce for internal combustion engines, means for supplying fuel and air thereto to form a combustible mixture, a throttle for regulating the ilow of such mixture to the engine, an air choke valve for controlling the proportions of fuel and air in said mixture,v

thermally responsive means for positioning said choke valve in accord-ance with variations in temperature and resilient means between the throttle and the thermally responsive means. said resilient means being operable by the throttle and eiective through the medium of said thermally responsive means to variably position the choke valve in accordance with different throttle positions.

21. In a charge `forming device for internal combustion engines, means for supplying fuel and ai'thereto to `form a combustible mixture, a-throttle for regulating the flo-W of such mixture to the engine, an air choke valve for controlling the proportions of fuel and air in said mixture. suction operated means for variably positioning the choke valve, and means operable by the throttie and effective" through the medium of said` suction operated means for also positioning said choke valve.

, operable by the throttle and effective through the medium of both the suction operated means and thermally responsive means to variably position said choke valve.-

23. In a charge forming device for internal combustion engines, means for supplying fuel and air thereto to form a combustible mixture, a throttle for regulating the flow 'of such mixture to the engine, an air choke valve for controlling the proportions of fuel and air in said mixture, thermally responsive means for holding the choke valve inclosed position at low temperatures, suction operated means for moving the choke valve toward open position and means operable by the throttle for also moving the choke valve toward open position, said last named means operating said choke valve through the medium of said suction operated means and thermally responsive means.

24. In a charge forming device for internal combustion engines, means for supplying fuel and air thereto to form a combustible mixture, a throttle for regulating the ow of such mixture to the engine, an air choke valve for controlling the proportions of fuel and air in said mixture,l

thermally responsive means for holding the choke valve in closed position at low tempeatures, suction operated means connected to said thermally responsive means and operable through the medium of the latter to move the choke valve toward open position and means operable by the throttle and effective to move said suction operated means to moveEthe choke valve toward open position.

-,25. In a charge4 forming device for internal combustion engines, means for supplying fuel and air thereto to form a combustible mixture, a throttle for regulating the :dow of such mixture to the engine, an air choke valve for controlling the proportions of fuel and airin said mixture, suction operated means for variably positioning the choke valve, means operable by the throttle and effective through the medium of the suction operated means to move said choke valve and means'for retrading the movement of said choke valve when so moved by the throttle.

26. In a charge forming device for internal combustion engines, means for supplying fuel and air thereto to form a combustible mixture, a throttle for regulating the flow of such mixture to the engine, an air choke valve for controlling` the proportions of fuel and air in said mixture, thermally responsive means for positioning said choke valve in accordance with variations in temperature, means operable by the throttle and effective through the medium of the thermally responsive means -to move said choke valve as the throttle is moved, and means to delay the movement of the valve with respect to the movement of the throttle.

27. In a charge forming device for internal combustion engines, means for supplying fuell and air thereto to form a combustible mixture, a throttle for regulating the flow of such mixture to the engine, an air choke valve `for controlling the proportionsof fuel and air in said mixture, 'thermally responsive means for holding the choke valve closed at low temperatures, means operable by the'throttle and effective through the medium of said thermallyresponsive means to move said choke valve toward open position and means to delay the movement of the choke valve with respect to the movement of the throttle.

28. -In a charge forming device for internal combustion engines, means for supplying fuel and air thereto to form a combustible mixture, a throttle for regulating the now of such mixture to the engine, an air'choke valve for controlling the proportions of fuel and air in said mixture, means for normally holding the choke valve closed when the engine is not in operation, means operable by engine intake suction for operating the choke valve and effective to move the valve towardopen position on increase of engine suction, means operable by the throttle and effective lthrough the medium of said suction operated means to move said choke valve toward open position and means for retarding the movement of said choke valve toward open position when moved by efl'ect of engine suction or by the throttle.

29. In a charge forming device for internal combustion engines, means for supplying fuel and air thereto to form a combustible mixture, a throttle for regulating the flow of such mixture to the engine, an air choke valve for controlling the proportions of fuel and air in said mixture, thermally responsive means for holding the choke valve closed at relatively low temperatures, suction operated means for moving the choke valve toward open position, throttle operated means eective through the medium of the thermally operated means to move the choke valve toward open Iposition and means to retard the movement of said choke valve toward open position when moved by efl'ect'of suction or by vthe throttle.

30. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible, mixture and a throttle for controlling the quantity of said mixture supplied to the engine mechanism for automatically controlling the proportions of fuel and air in said `mixture comprising a member forV variably regulating the admission of one of the' components of such mixture, means normally holding said member in position to enrich the mixture, suction operated means for moving said member toward its mixture leaning position, means operable by the throttle and effective to similarly move said member, and means for retarding the movement of said member toward its mixture leaning position when moved by effect of engine suction or by the throttle.

3l. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the quantity of said mixture supplied to the engine, mechanism for automatically controlling the proportions of fuel vand .air in said mixture comprising a member for components of such mixture, means normally holding said member in position to enrich the mixture, suction operated meansy for moving said member toward its mixture leaning position, means operable by the throttle and effective to similarly move said member, and a dash pot connected to said suction operated means for retarding the movement of said .mixture controlling member toward its mixture leaning position when moved by the eiect of suction or by' the throttle.

33. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the quantity of said mixture supplied to the engine, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a member for variably regulating the admission of one of the components of such mixture, thermally responsive means for holding said member in position to enrich the mixture when the temperature is relatively low, means operable by the throttle and effective through the medium of the thermally responsive means to move said member to a position to lean the mixture, and means for retarding t-he movement of said member with respect to the movement of the throttle.

34. In a charge forming device having a mixture passage, means for supplying fuel and air.

thereto to form a combustible mixture and a throttle for controlling the quantity of said mixture supplied to the engine, mechanism for autonatically controlling theproportions of fuel and air in said mixture comprising a member for variably regulating the admission of one of the components of such mixture, thermally responsive means for holding said member in position to enrich the mixture when the temperature isrelatively low, means operable by the throttle and eifective through the medium of the thermally responsive means to move said member to a position to lean the mixture, means for retarding the movement of the said member with respect to the movement of the throttle and means for varying the eifect of the'retarding means in accordance with the position of said mixture controlling member.

35. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for controlling the admission to the charge forming device of one of the components of said mixture, a thermostat for variably positioning said valve in accordance with temperature conditions, an operating member connected to one end of the thermostat and adapted when moved to variably position said mixture controlling valve, a throttle shaft having a cam thereon, and a resilient operating element between said cam and said operating member-to cause a movement of the latter cam is operated.

36. In a charge forming device having a mixture passage, means for supplying fueland air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for controlling the admission to the charge formingdevice of one of the components of said mixture, a thermostat for variably positioning said valve in accordance with temperature conditions, an operating member connected to one end of the thermostat and adapted when moved to variably position said mixture controlling valve, a suction operated piston operatively connected to said operating member to effect movement of the latter upon changes in engine suction, a throttle and means operable thereby for moving said suction operated piston as the throttle is moved.

37. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the flow of said mixture,

mechanism for automatically controlling the protioning said valve in accordance with tempera-l ture conditions, an operating member connected to one end of the thermostat and adapted when moved to variably position said mixture 'controlling valve, a suction operated piston operatively connected to said operating member to eiiect movement of the latter upon changes in engine suction, a` throttle, and a resilient operating means between the throttle and said suction operated piston whereby the latter is movable by said throttle as the throttle is moved to dinerent positions.

38. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the ow of. said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for controlling the admission to the charge forming device of one of the components of said mixture, a thermostat for variably positioning said valve in accordance withtemperature conditions, a driving member operatively connected to the thermostat so that movements of the driving member are communicated to the v mixture controlling valve through the medium of the driving member, a throttle, and

erated bythe throttle for moving said operating said thermostat, means` for moving said driving member by the effect of engine suction in order -to eifect movements of the mixture controlling member in response to variations in engine suction, an operating rod resiliently connectedto means 0pwhen the ture conditions, `a driving member operatively connected to the thermostat so that movements of .the driving member are communicated to the mixture controlling valve through the medium oi said thermostat, means for moving said driving member by the eiect of engine suction in order to eect movements of the mixture controlling member in responsev to variations in engine suction, an operating rod resiliently connected to the driving member, a throttle, means'operated by the throttle for moving said operating rod to eil'ect movement of the driving member and a dash pot connected to said operating rod to retard the movements of the latter.

40. In a charge formingdevice having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling. the ow of said mixture, mechanism for automatically controlling the proportions of fel and air in said mixture comprising a valve for controlling the admission to the charge forming device of one of the components of said mixture, a thermostat for variably positioning said valve in accordance with temperature conditions, a driving member operatively connected to the thermostat so that movements of the driving member are communicated to the mixture controlling valve through the medium of said thermostat, means for moving said driving member by the effect of engine suction in order to eiIect movements of the mixture controlling member in response to variations in engine suction, an operating member resiliently connected to said driving member so as to operate said driving member and to provide for relative movement between said members, a throttle, and a second resilient operating connection between said throttle and said operating member.

41. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the ilow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for controlling the admission to the charge forming device of one of the components oi' Ysaid mixture, a thermostat for variably positioning said valve in accordance with temperature conditions, a driving member operatively dii.

movement oi the operating member with respect to the movement of -the throttle.

42. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the ow of said mixture, mechanism for automatically controlling the -proportions of fuel and air in said mixture comprising a valveior controlling the admission to thecharge forming device of one of the components of said mixture, a thermostat for variably positioning -said valve in accordance with temperature conditions, a driving member operatively connected to the thermostat so that movements of the driving member are communicated to the mixture controlling valve through the medium of said thermostat, an operating rod resiliently connected at one end to the driving member, a throttle, means operated thereby for moving said operating rod to effect movement of the driving member, and a dash pot connected to the opposite end of said operating rod to retard the movements of said rod.

'43.. In a charge forming device having a mixture passage, means for supplying fuel and airthereto to form a combustible mixture and a throttle for controlling the ilow of said mixture, mechanism for automatically controlling the proportions of fuel and air in said mixture comprising a valve for controlling the admission to the charge forming device of one of the components of said mixture, a thermostat for variably positioning said valve in accordance with temperature conditions, a driving member operatively connected to the thermostat so that movements of the driving member are communicated to the mixture controlling valve through the medium of said thermostat, a suction operated piston rigidly connected to said driving member for moving said member in response to variations in engine suction, an operating rod resiliently connected to said driving member so as to be movable relatively thereto, a throttle, and a second resilient operating connection between the throttle'and said operating rod.

44. In a charge forming device having a mixture passage, means for supplying fuel and air thereto to form a combustible mixture and a throttle for controlling the iiow of saidI mixture, means for automatically controlling the proportions or fuel and air in said mixture comprising an air valve for regulating the admission of air to the charge-forming device, mechanism for positioning the air valve in accordance with temperature conditions and engine suction and throttle operated'means effective through said mechanism to variably control the position of said air valve in accordance with the position of the throttle. A

CLARENCE H. J ORGENSEN.