US2085351A

US2085351A - Carburetor

Info

Publication number: US2085351A
Application number: US679201A
Authority: US
Inventors: Irven E Coffey
Original assignee: Carter Carburetor Corp
Current assignee: Carter Carburetor Corp
Priority date: 1933-07-06
Filing date: 1933-07-06
Publication date: 1937-06-29
Anticipated expiration: 1954-06-29

Description

I. E. COFFEY GARBURETOR Filed July 6, 1933 3 Sheets-Sheet l mwlgg,

IRYEN E. COFFEY INVENTOR F l G. I

ATTORNEY I. E.' COFFEY June 29, 1937.

CARBURETOR Filed July 6, 1933 5 Sheets-Sheet 3 F l G". 3

IIHII IRV EN E. CO FFEY INVENTOR A TTORNEY Patented June 29, 1937 PATENT OFFICE CARBURETOR Irven E. Coffey, St. Louis, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application July 6, 1933, Serial No. 679,201

40 Claims. (01.123-179) This invention relates to carburetors and particularly to automatic control devices for controlling the fuel mixture under low temperature conditions. In previous devices of this character the use of a bi-metallic coil thermostat has been suggested but difliculties have been encountered in getting the thermostat to heat up quickly enough after the motor starts so as to open the chokevalve as soon as the engine is in a warm enough condition to use a leaner mixture. Difficulty has also been encountered in obtaining a suitable means to open the throttle valve or otherwise to supply sufficient mixture to the engine iii! keep it running when the oil is cold and viscous.

With .the'throttle in its normal closed position only suflicient air is admitted to the engine to produce power enough to turn it over at idling speed under normal temperature operating conditions so that if the throttle is left in this position when the oil is cold and viscous, the engine simply does not have power enough to run and it stops. Inasmuch as the throttle is normally held in closed position by a fairly stiff spring and since it is desired to reduce the bi-metallic coil thermostat to small proportions on account of expense, difficulty has been had in obtaining suificient power to automatically open the throttle when theengine cools off between periods of operation.

Another difliculty that has been had with previous installation is that the thermostat has generally been mounted on the exhaust manifold or the hot spot of the. intake manifold, an arrangement which requires the coupling of the thermo- 35 stat by comparatively long linkage to the choke valve of the carburetor, and since the carburetors are not usually manufactured in the same factories where the engine is built, the assembly of these parts is not done by carburetor men but by 40 general automobile mechanics and improper adjustment frequently results.

The object of this invention is to produce a generally new and improved automatic device for controlling the admission of fuel to the engine 5 under low temperature conditions and to eliminate or alleviate the above described difllculties. The invention will be better understood upon reference to the accompanying drawings, referring to which:

, Figure 1 is a side elevation of a carburetor constructed according to my invention, parts being broken away and others shown in section.

Figure 2 is a sectional elevation of a carburetor constructed according to my invention, the view 55 being taken from the side opposite to that shown in'Figure 1, and parts being broken away and others shown in section.

Figure 3 is a detail sectional view taken along the line 33 of Figure 2 looking in the direction of the arrows.

Figure 4 is a detail sectional view taken along the line 44 of Figure 1, looking in the direction of the arrows.

Figure 5 is a plan view of the device.

Figure 6 is a detail view taken along the line 6-6 of Figure 3, looking in the direction of the arrows.

The reference numeral I indicates the main body member of a carburetor mounted by means of a flange 2 on the intake manifold 3 of an internal combustion engine. The exhaust manifold isshown at 4. The carburetor comprises the usual throttle valve 5 controlled by a manually operated lever 6, a connection I to foot pedal or dash being provided. A float chamber 8 is formed integral with the main casting of the carburetor and fuel is maintained at substantially the level AA by floatv mechanism diagrammatically indicated at 9. Fuel is supplied from the float chamber to a main nozzle H) by means of the main jet I l and a metering rod I2 is provided for controlling the main jet in accordance with the throttle position. The main nozzle l0 discharges at the throat of the venturi l3, which, in the present instance discharges into other and larger venturis to form a multi-stage mixing arrangement; this construction is already well known in the art, and no further description is necessary. A diaphragm i4 is subjected to the suction in the intake manifold of the engine by means of the conduit I5, is mounted on the body of the carburetor by means of the bracket l6 and connected to rocker arm II by means of the'rod IS. A spring I9 is provided for moving the'diaphragm to the right with respect to Figure 1 and this spring has sufiicient strength to open the throttle valve by the means hereafter to be described, but the spring is still weak enough to be overcome by a suction in the intake manifold amounting to 6 or 7 pounds per square inch so as to permit the throttle to move to fully closed position.

The rocker arm I! is fixedly mounted on the rock shaft 20 which is also provided with the lever 2! fixed thereto. The lever 2i is provided with a transversely bent portion 22 at its end to insure contact with the lever 23 which is mounted on the throttle shaft 24. Obviously when there is no suction in the intake manifold, spring l9 pushes diaphragm M to the right with respect to Figure 1 and rotates shaft 20 in a clockwise direction thereby causing the transverse portion 22 to contact with and move the lever 23 to slightly open the throttle as soon as the engine stops and to hold it there until the engine is cranked again and begins to run under itsown power. A second lever 26 is mounted on the throttle shaft to rotate therewith and connected by means of link 26 with rocker arm 21 carried by rock shaft 26. The link 26 is provided with an inwardly projecting pin 23 for a purpose hereafter to be described. 1 v

The choke valve 33 is eccentrically mounted on shaft 3| which extends thru the wall of the air horn 32 and is provided at one end with an arm 33 having a slot 34 therein. A link 36 has a pin 36 loosely mounted in slot 34 and serves 7 for connecting the choke valve to a rocker arm 31 which is pivotally mounted on the pillow block 38 by means of the pin 33. The rocker arm 31 is provided with a lug 46 adapted to contact the corresponding lug 4| carried by the rocker arm 21. When the choke valve is in the closed position as indicated in Figure 1, the normal position of the lug 43 is such as to prevent anticlockwise movement of the rocker arm 21 by reason of contact between

lugs

43 and 4|. This position of rocker arm 21 corresponds to a slightly open position of the throttle valve and insures the supply of sufllcient air to the engine to keep it in operation at low temperatures. Whenever the choke is moved to open position, the rocker arm 31 is moved in a clockwise direction with respect to Figure 1 and lug 43 is moved out of the path of lug 4i permitting the throttle valve to be returned to its normal idling position. Due to the provision of the slot 34, there is no interference between the

lugs

40 and 4| during a closing movement of the choke valve even if, for some reason, the throttle valve should be in fully closed position. In case of failure of the diaphragm E4 to move the throttle valve to partially open position when the engine stops, the choke valve would be moved to fully closed position upon the subsequent cooling of the engine,

and the throttle valve would remain in' closed position until it shouldbe operated manually. As soon as the throttle valve is operated manually to a sufficiently open position, the rocker arm 31 would drop down by'gravity to the position indicated in Figure Land the re-closing of the throttle would be prevented until the choke valve had been opened sufficiently to move the lug 40 out of the path of lug 4|.

The other end of the choke valve shaft 3| extends into a housing 42 which is thoroughly lined with cork or other heat insulating material as indicated at 43. The casing is formed in two parts as indicated in Fi re 3, the outer portions being cup-shaped and removable, and a radial lever arm 44 is rigidly secured to the end of the choke valve shaft 3| within the housing 42. The end of the lever 44 is connected to a disk-shaped piston 45 by means of the curved connecting rod 46 as indicated in Figure 2. This piston 46 01')- erates in a chamber 41 which is formed within the housing 42 in the shape of a portion of an annulus so that the piston 45 may simultaneously slide within the cylinder 41 and rotate about the center of the shaft 3|. The cylinder 41 is provided with grooves or by-passes 48 formed on its opposite flat sides. The by-passes do not extend the full length of the'cylinder and when the piston 46 is in the position shown in Figure 2, the by-passes are closed by the piston,

a,oss,ss1

also when the piston 46 is moved as far as it will go in a clockwise direction with respect to Figure 2, the by-passes are again closed. The by-passes 43 are formed with an irregular contour so as to provide an uneven suction action on the piston 46. In order to provide for variations in the circularity of the cylinder 41, the piston 46 is pivoted to the connecting rod 43 as indicated at 43. In order to obtain heat for warming up the thermostat when the engine starts, a hot air stove 63 is provided on the exhaust manifold 4 and hot air is drawn up from the stove directly thru the conduit 6| to the interior of the housing 42. The moving force which draws the hot air thru the housing 42 is the suction of the intake manifold which is conveyed by means of a conduit 63 to the cylinder 41 in such a manner that the suction existing in the intake manifold is transmitted to the piston 46 and whenever the piston 46 has been moved in a clockwise direction with respect to Figure 2 far enough to uncover the by-pass 43, a strong draught of hot air is drawn from the conduit 5| thru the housing 42 and the by-pass 43, thus warming up the inside of the housing and the thermostat 64. The conduit 53 is provided with a valve screw 15 by which the suction may be regulated. The

thermostat 54 is fixedly mounted on the removable portion of the housing 42 by means of a pin 66. The outer portion of the housing is held in place by means of a flexible bracket 56 of well known construction. This bracket is pivoted at 51' so that it may be swung aside to permit complete removal of the thermostat and the outer portion of the housing. The thermostat may be rotatably adjusted by turning the housing to the right or left and will be held in adjusted position by friction created by the pressure of the flexible bracket 56 against the outer portion of the housing.

The outer end of the thermostatic coil is provided with a hook which engages the pin 53 which projects from vthe lever 44. The thermostat is of the bi-metallic coil type and the metals are so arranged as to rotate the lever 44 and the choke valve in an anti-clockwise direction with respect to Figure 2 when the temperature is low; in other words thechoke valve will be closed when the engine is cold.

It will be noted that the hook on the end of the thermostatic coil which engages the pin 58 operates the choke valve in one direction only. The reason for, this form of connection is to permit the thermostat to freely move without obstruction by any other element when the temperature is high, it being a well known characteristic of thermostats that they must not be subjected to strain when the temperature is above a predetermined degree. It will also be understood that the thermostat is, in efiect, connected to the choke valve although the connection is such as to act in one direction only.

I have found it highly desirable to provide a fluttering action for the choke valve during the cranking of the engine. In order to do so I provide a magnet 53 which may have the regular horse-shoe shape or be slightly curved as indicated in Figure 2. This magnet is held in place by means of the brass screw 63 and the lever 44 has an upturned portion 6| which serves as an armature for the magnet. The member 6| is, of course, constructed of'iron or other magnetic-material and contacts with the poles of the magnet'when the choke valve is moved to fully closed position. It should be clearly understood that the magnet 55 is not of great strength,

anditsieifect o'n'the closing movement of thechoke valve is completely negligible until the armature G] is brought "in substantial contact with the magnet. The thermostat 54 is the only device supplying any substantial amount of power to move the'choke'valve toward closed choke valve closed, there is substantial suction in the mixing chamber of the carburetor result-.

ing in the discharge of large quantities of fuel from the main nozzle ill, but the rate of air 'flowing thru the mixing chamber 55 of the carburetor is practically nil, the only air being admitted with the choke valve in closed position being the leakage past said valve. Obviously it takes a current of air to carry vaporized fuel to the engine. Otherwise it would be necessary to wait until the intake manifold practically filled up with liquid fuel before the cylinders received any. In previous constructions this small amount of air for conveying the original charges has been supplied by means of a bleeder hole, or small check valve mounted within the choke valve or in some equivalent location. Such devices supply a small constant current moving at low speed and most of the fuel vapor carried by such current was either condensed on the walls of the manifold or otherwise precipitated the moment it reached the cylinders. One of the objects of this invention is to secure the movement oi?v the air current from the carburetor to the cylinders in a succession of comparatively rapid impulses instead of in a steady flow or stream, the impulsive movement apparently having a better vaporizing effect on the gasoline and being more efficient to retain the gasoline in vaporized position. One reason for this improved result is, of course,that the current moves in impulses and the individual impulses move at a much higher velocity when the air is ad- "mitted intermittently than would be obtained if the air was admitted constantly thru a small In operation when the motor is not running there is no suction in the intake manifold and the spring I! movesv diaphragm l4 to the right with respect to Figure 1, causing the partial opening of the throttle valve so as to admit ample fuel mixture to the engine during the cranking period and during the first fw revolutions when it runs under its own power. The throttle valve being moved to partly open position, raises valve to move toward closed position until the access;

lug 4| contacts with the lug 40,,thereby preventing the complete closing of the throttle; valve and leaving it in the fast idle position. During the cranking period the choke valve is intermittently opened by the suction and closed again by the thermostat at a fairly rapid rate, the

fluttering action being caused by the effect of the magnet 59. It will be understood thatthe magnet has somewhat the effect of a snap action device which prevents the choke valve remaining fixed in a position which would leave the armature 5| in close proximityto the poles of the magnet but not contacting therewith.

For instance if the armature Si is within 9. V

of an inch of the poles of the magnet, the combined strength of the thermostat and the magnet would generally be sufllcient to move it quickly to fully closed position, the action of the suction being elastic and the movement of the piston of the engine being slow during the cranking period, so that anappreciable length of time is required to build up suflicient suction to overcome the combined action of the thermostat and-the effects of the magnet on the armature 5|. When the suction is built up to such a point that it is strong enough to break the armature away from the poles of the magnet it is also strong enough to carry the valve a substantial distance beyond that necessary to admit the air at the rate at which it is being drawn in by the cylinders. The suction in the carburetor and intake manifold is accordingly immediately reduced to practically nothing and the choke valve swings back toward closed position under the'influence of the thermostat, acquiring sufflcient momentum in doing so to move the armature 5i into contact with the poles of the magnet, and then the operation is repeated.

As soon as the engine begins to run under its own power, a substantial amount of suction .is developed in the intake manifold and this suction is transmitted thru the conduit 53 to cylinder 41 and piston 45. It will be understood, of course, that there is some suction in the intake manifold even during the cranking period, and this contributes to a certain extent to the opening of the choke valve during the cranking period, but the effect is' more or less minimized by the fact that the piston 45 does not fit tightly and there is some leakage around it in the cylinder 41. When the engine is running under its own power, however, the suction is built up'in the intake manifold to such a value that'the eflfecton piston is very definite, being strong enough to overcome the action oi the thermostat and open the choke valve to an extent depending on the temperature, the speed at which the engine may be'running and on the'position of the throttle valve 5. This movement of the piston 45 in a direction to open the choke valve also opens the passageway thru by-pass 48 which permits hot air to be drawn up rapidly from the air stove 50. It will be understood, of course, that the air is not warm during the first few seconds of the running of the engine, but since the stove is mounted on the exhaust pipe it is only a short time until it becomes heated up. The high suction in the intake manifold draws a strong draught from the stove 50 which, of course, is open to the atmosphere and the thermostat in the insulated housing 42 is quickly warmed up so that the choke valve is soon moved to full open position. v

In order to properly control the movements of the choke valve in response to the action of the piston u. the capacity or the conduit u may be controlledin any suitable manner. This control may be accomplished by merely selecting a propel-size for the tube 53 or by the insertion of a restricted orifice or an adjusting valve as shown at 15 or any other suitable means.. A similar adjustment could also'be made for the -coriduit I Ithot to maintain the choke valve in fully open position. It is not necessary, however, to exceed temperatures of approximately 200 degrees Fahrenheit inthe chamber 54 so that comparetively inexpensive thermostatic metal may be used.

Once the thermostat has been moved to fully' open position the insulation 43 prevents the rapid cooling of the thermostat and avoids the supply of an over-rich mixture to a motor which has been recently operating and has not yet cooled down to a point where such rich mixture is required. i In case the engine does not start during the initial cranking it may become over-loaded and insuch case it is desirable to provide manual means for opening the choke valve when clearing out the engine. Such means are provided in the pin 29 which contacts with the lower part of the lever 31 when the throttle valve is moved to fully open position so that the operator can, by simply holdingthe throttle open, push the link 26 upwardly rotating the arm 31 in clockwise direction with respect to Figure 1 and opening the choke valve so that'with a few seconds fur,- ther cranking the cylinders can be relieved of the excess gasoline.

The irregular contour of the by-passes lid is provided in order that the mixture ratio of air and gasoline may be definitely controlled for any particular engine by changing the contour. As the, piston 45 moves ina clockwisedirection with reference to Figure 2, the pull of the suction upon the piston is varied according to the particular contour of the by-passes thereby causing the choke valve 30to be opened a predetermined distance for any particular suction which may be set up in the intake manifold. This action is provided in order that there may be greater economy and more eflicient' operation.

The invention is not limited in details to the structure shown but may be modified in various respects as will occur to those skilled in the art and the exclusive use of all such modifications that come within the scope of the appended claims is contemplated.

A part of the subject matter shown but not claimed herein is shown and claimed in applicants divisional application. Serial No. 117,822, filed December 28, 1936, for improvements in Carburetors. and in applicants application, Serial No. 134,070, filed March 31, 1937, for improvements in Carburetors, whichis a continuation, in part. of the present application.

I claim:

L'In an internal combustion engine having an intake manifold and an exhaust manifold, a

carburetor mounted on said intake manifold, said carburetor having a choke valve, a housing mounted on said carburetor, a conduit having an conditions.

2. In an .internal combustion engine having an intake manifold and an exhaust manifold, a carburetor connected to said intake manifold, said carburetor having a chokevalv'e, an air heating device on said exhaust manifold, a housing on said carburetor adjacent said choke valve, 8. heat responsive device for operating said choke valve, means for conveying air from said air heating device to said housing, said means including a conduit having an outlet end within said housing, a suction responsive device in said housing for operating the choke valve, a suction .conduit for said suction responsive device, and said suction conduit having an inlet from said housing to cause the flow of. heated air therethroug 3. In an internal combustion engine having an intake manifold and an exhaust manifold, a carburetor mounted on said intake manifold, said carburetor having a choke valve, a heat responsive device and a suction responsive device connected to said choke valve, an insulated housing'enclosing said heat and suction operated devices, a suction connection between said hous ing and said inlet manifold for operating said suction operated device, an air heating device mounted on said exhaust manifold, and a conduit for conveying heated air from said air heating device to said housing.

4. In an internal combustion engine having an -intake manifold and an exhaust manifold, a

carburetor mounted on said intake manifold, said carburetor having a choke valve, a heat responsive. device and a suction responsive device connected with saidchoke valve, a housing enclosing said heat and suction responsive devices, a suctionconnection between said housing and said inlet manifold for operating said suction re sponsive device, an air heating device mounted on said exhaust manifold, and a conduit for conveying heated air from saidair heating device to said housing, said suction responsive device being constructed and arranged to by-pass a certain amount of air when the choke valve is in partly open position and to substantially close the by-pass when the choke valve is in fully open position. v

5. In an internal combustion engine having an intake manifold and an exhaust manifold, a carburetor mounted on said intake, manifold, said carburetor having a choke valve, a heat responsive device and a suction responsive device connected with said choke valve, a housing enclosing said heat and suction responsive devices, a suction connection between said housing and said intake manifold for operating said suction responsive device, and an air heating device mounted on said exhaust manifold, a conduit for conveying heated air from said air heating device to said housing, said suction responsive device being constructed and arranged to bypass a certain amount of air when the choke valveclose the by-pass when the choke valve is in fully open position, said suction responsive device being also constructed and arranged to substantially prevent the by-passing of air when the choke valve is in fully closed position.

6. In a carburetor, a choke valve, a shaft for said choke valve, an operating lever mounted on said shaft, a connecting rod having a circular axis connected to said lever and substantially concentric with said shaft, a piston on one end of said connecting rod, and suction means for operating said piston.

'7. In a carburetor, a choke valve, a choke valve shaft, an expansible chamber in the form of a portion of an annulus surrounding said shaft, a connecting rod connected to said lever and made in the form of a portion of a circle concentric with said shaft, and a piston for said connecting rod. slidably mounted within said expansible chamber. 1

8. In a carburetor, means forming a mixing conduit, a choke valve mounted at the inlet of said mixing conduit, a choke valve shaft mounted transversely with respect to said mixing conduit and attached to said choke valve, said shaft being eccentric with respect to said choke valve, whereby the choke valve may be moved toward open position by suction, an operating lever mounted on said shaft, a cylinder having a curved axis concentric with the axis of said shaft, a piston in said cylinder, a rod connecting q said piston with said lever, and means for applying suction to one end of said cylinder.

9. In a carburetor, means forming a mixing conduit, a choke valve mounted at the inlet of said mixing conduit, a shaft transversely mounted in said mixing conduit and attached to said choke valve, said shaft being eccentric with respect to said choke valve, whereby the choke valve may be moved toward open position by suction, an operating lever for said shaft, a cylinder having a curved axis concentric with the axis of said shaft, a piston in said cylinder, a rodconnecting said piston and said lever, and means for applying suction to one end of said cylinder, said means comprising a conduit connected to the intake manifold of the engine.

10. In a. carburetor, means forming a mixing conduit, a choke valve mounted at the inlet of said mixing conduit a transverse shaft mounted in said mixing conduit and attached to said choke valve, said shaft being eccentric with respect to said choke valve, whereby the choke valve may be moved, toward open position by suction, an

F operating lever for said shaft, a cylinder having a'curved axis concentric with the axis of said shaft, a piston in said cylinder, a rod connecting said piston with said lever, means for applying suction to one end of said cylinder, and a heat responsive device for moving said choke valve toward closed position.

, 11. In a carburetor means forming a mixing conduit, a choke valve mounted at the inlet of said mixing conduit, a transverse shaft mounted in said mixing conduit, and attached to said choke valve, said shaft being eccentric with respect to saidchoke valve, whereby the choke valve may be moved toward open position by suction, an operating lever for said shaft, 8. cylinder having a curved axis concentric with the axis of said shaft, a piston in said cylinder, a rod connecting said piston and said lever, means forapplying suction to one end of said cylinder, 2. heat responsive device for moving said choke valve toward closed position, and means for setting up a fluttering action of said choke valve during the cranking of the motor.

12. In a carburetor, means forming a mixing conduit, a choke valve mounted at the inlet of said mixing conduit, a transverse shaft mounted in said mixing conduit, and attached to said choke valve, said shaft being eccentric with respect to said choke valve, whereby the choke valve may be moved toward open position by suction, an operating lever mounted on said shaft, 9. cylinder having a curved axis concentric with the axis of said shaft, a piston in said cylinder, a rod connecting said piston and said lever, means for applying suction to one end of said cylinder, a heat responsive device for moving said choke valve towards closed position, and means for setting up a fluttering action of said choke valve during each individual suction stroke of the motor during the cranking period.

13. In a carburetor, means forming a mixing conduit having a throttle controlled outlet and a choke controlled inlet, a choke shaft, heat and suction responsive devices operatively'associated with said shaft, a. housing for said heat responsive device, and insulating means for preventing the rapid transfer of heat away from said heat responsive device.

14. In a carburetor, means forming a mixing conduit having a throttle controlled outlet and a choke controlled inlet, a choke shaft, heat and suction responsive devices operatively associated with said shaft, means for heating said heat responsive device, a housing for said heat responsive device, and insulating means for preventing the rapid transfer of heat from said heat responsive device to the outer atmosphere.

15. In a carburetor, an air horn having a choke valve therein, a shaft for said choke valve mounted within said air horn, a housing mounted on said air horn at one end of said choke valve shaft, a heat responsive device within said housing, means for heating said heat responsive device, and insulating means to prevent the rapid transfer of heat away from said heat responsive device.

16. In a carburetor, an air ho'rn haxing a choke valve mounted therein, a shaft for 'said 'choke valve mounted in said air horn, a heat responsive element mounted on said air horn at one end of said shaft, a housing for said element, means for admitting heated air to said housing, a suction connection from said housing to the intake manifold of the engine, a part of said connection being formed to receive a suction responsive element, and a suction responsive element loosely mounted in said part of the connection.

17. In a carburetor, an air horn having a choke valve mounted therein, a shaft for said choke valve mounted in said air horn, a heat respons e element mounted on said air horn at one end of said shaft, said heat responsive element being constructed and arranged to close said choke valve when the temperature is low, a housing for said element, means for admitting heated air to said housing, a suction passageway leading from said housing to a suction producing device, whereby heated air is caused to flow through said housing to said suction producing means, and a suction responsive element connected to said choke valve, said suction responsive element being exposed to the suction in said suction passageway and adapted to be operated thereby.

1 8. In a carburetor, an air horn having a choke valve mounted therein, a shaft for said choke valve mounted in said air horn, a heat responsive element-mounted on said air hornat one end of said shaft, a housing for said element, means for admitting heated air to said housing, a suction connection from said housing to the intake manifold of the engine, a suction responsive element mounted in a part of saidconnection and connected to the choke valve, and means for restricting said suction connection when the choke valve is in fully closed position.

19. In a carburetor, a choke valve, a heat responsive element for controlling said choke valve, means for applying heat to said heat responsive element, and means for controlling the application of said heat in accordance with the position of said choke valve, said last named means including a suction responsive element which is connected with the choke valve.

20. In an internal combustion engine, a carburetor having a choke valve, a heat responsive device for controlling said choke valve, an air heating device, a housing for said heat responsive device, means for causing the flowof heated air irom'said air heating device thru said housing to heat said heat responsive element, and means for controlling the rate otnflow'of said heated air in accordance with the position of said choke valve, said last named means including a suction responsive element which is connected with the choke valve.

21. In an internal combustion engine, a carburetor, an intake manifold and an exhaust manifold, a choke valve for said carburetor, an air heating device mounted on said exhaust man- 11016., a housing, a heat responsive element within 1 said housing, said heat responsive element bein constructed and arranged to close said choke valve when the temperature is low, an air passage from said air heating device to said housing, a suction operated device connected with said choke valve and receiving air from said housing, a suction connection from the intake manifold to said suction operated device, said suction operated device being constructed and arranged to by-pass varying amounts of air in accordance with the position of said choke valve.

22. In a carburetor, a choke valve, a suction responsive device for operating said choke valve, said suction responsive device comprising a piston and a cylinder, means including a restricted conduit for applying suction to said cylinder, said cylinder being slightly larger than said pis-v ton and varied in size at different points: of its length, whereby the responsiveness of said piston to suction will vary in accordance with the position oi said piston in said cylinder.

23. In a carburetor, a choke valve, a suction responsive device for operating said choke valve. said suction responsive device comprising a piston and a cylinder, means including a restricted conduit for applying suction to said cylinder, said cylinder being slightly larger than said piston and varied in size at different points of its length whereby the responsiveness of said piston to suction will vary in accordance with the posi- I tion of saidv piston in said cylinder, and a heat responsive device for controlling said choke valve.

24. In a carburetor, a choke valve, a suction responsive device for controlling said choke valve, said suction responsive device comprising a piston and cylinder, said piston having a close fit at each end 0! said cylinder and a loose fit in the middle of said cylinder whereby the responsiveness of. said device to suction will be less in an intermediate position than in either of its extreme positions.

25. In a carburetor, an air horn, a choke valve mounted in said air horn, a housing mounted on said air horn, a heat responsive element within said housing for controlling said choke valve, a suction responsive device within said housing for exercising a further controlling effect on said choke valve, an air heating device for delivering heated air to said housing, a suction connection for applying a suction to said suction responsive device, said suction responsive device comprising a cylinder open at one end of said housing and a piston within said cylinder, said cylinder being provided with a by-pass for permitting the rapid withdrawal of heated air from said housing when said piston is in a predetermined position. 7 t

26. In an internal combustion engine, an intake conduit, a carburetor communicating therewith,

a throttle valve in said carburetor, a choke valve in said carburetor and responsive to suction therein, a suction responsive device for influencing said choke valve, said device communicating with said intake conduit, and a heat responsive device for urging said choke valve towards its closed position when the engine is cold, said suction responsive device also comfor controlling said first mentioned means.

28. In an internal combustion engine having an intake passage and an exhaust passage, a device for supplying fuel mixture to said intake passage including a heat responsive device for controlling the richness of the mixture supply inversely in accordance with the temperature, a suction responsive device for controlling the richness of the mixture inversely in accordance with suction, a housing for said heat and suction responsive devices, means for supplying heat to said heat responsive device, and a suction connection for conveying suction from said intake passage to said suction operated device.

29. In an internal combustion engine having an intake conduit provided with a choke valve and an exhaust conduit, 0. device for supplying fuel mixture to said intake conduit including a housing, a heat responsive device and a suction responsive device in said housing, said heat and suction responsive devices having connections for operating said choke valve, a conduit for conveying air heated by said exhaust conduit to said housing for heating said heat responsive device, said suction responsive device comprising a piston having one end exposed to the pressure within said housing, and a suction connection for applying suction from said intake conduit to the other end of said piston.

30. A device as described in claim 29, and in which said intake conduit is provided with a throttle, and said suction connection is connected to said intake passage at a point posterior to the throttle.

31. In a carburetor having a choke valve and a throttle, a shaft for the choke valve, a thermo static spring operatively connected to the shaft to rotate the same, a casing enclosing the thermostatic spring, means for conveying heat to said casing, a cylinder having one end communicating with said casing and its other end connected to a source of variable pressure, a piston in said cylinder, and means connecting the piston with the choke valve whereby movement of the piston will cause a movement of said choke valve.

32. In a carburetor, a throttle, an unbalanced choke valve mounted on a shaft, a bimetallic spring connected to said shaft to rotate the same, a casing enclosing said spring, a conduit for conveying heated gases to the casing, and a pressure-responsive member having one surface subject to the pressure in the casing and another surface subject to the suction posterior to the throttle, said pressure-responsive member being provided with means connecting it to the choke valve whereby movement of the pressure-responsive member varies the position of said choke valve.

33. In a carburetor, a throttle, a pressure-responsive choke valve mounted on a shaft, a thermostatic spring of spiral form connected to said shaft to rotate the same, a casing enclosing the thermostatic spring, a conduit for conveying heated air to the casing, a cylinder communicating with the casing, and a piston therein having one face subject to the pressure in the casing and its opposite face subjected to pressures posterior to the throttle, said piston being provided with means connecting it to the choke valve, whereby movement of the piston will vary the position of the said choke valve.

34. In a carburetor for an internal combustion engine, a throttle, a pressure-responsive choke valve mounted on a shaft, a thermostatic spring connected to said shaft to yieldingly urge the choke valve toward closed position at low temperatures, a casing fixed to the outer wall of the carburetor and enclosing the thermostatic spring, a conduit for conveying heated gases from a heated portion of the engine to the casing, a conduit leading from the casing to a point posterior to the throttle, and means for varying the position of the choke valve comprising a pressure-responsive member in said last mentioned conduit subject to the varying pressures therein and applied to the choke valve by .an overrunning connection.

35. In a carburetor for an internal combustion engine, a throttle, a pressure-responsive choke valve mounted on a shaft, a spiral bimetallic spring connected with said shaft to yieldingly urge the choke valve toward closed position at low temperatures, a casing fixed to the outer wall of the carburetor and enclosing the thermostatic spring, a conduit for conveying heat from a heated portion of the engine to the casing, a second conduit leading from the casing to a source of suction, and means for varying the position of the choke valve comprising a piston in said second conduit connected to the choke valve by an overrunning connection.

36. In a carburetor for an internal combustion engine, an air inlet passage, an induction passage, a throttle valve controlling the induction passage, an unbalanced choke valve controlling the air inlet passage, temperature responsive means controlling the choke valve and adapted to move the'choke valve in the closing direction at low temperatures, a casing carried by the walls of the air inlet passage and enclosing said temperature responsive means, means including a conduit to convey heated gases from a heated portion of the engine to the interior of the casing, means including a conduit interconnecting the casing and the induction passage posterior to the throttle valve, and means including a pressure responsive member in said last mentioned conduit subject to varying pressures therein for varying the position of the choke valve.

37. In a carburetor for an internal combustion engine, an induction passage, an air inlet passage communicating with the induction passage, a throttle valve controlling the induction passage, an unbalanced pressure responsive choke valve controlling the air inlet passage, a casing fixed to the outer walls of the air inlet passage, a choke shaft journalled in the walls of the air inlet passage and projecting into said casing, temperature responsive means in the casing and operably connected to the choke shaft to modify the position of the choke valve in accordance with the temperature of the engine, means including a conduit to convey heated gases from the engine to the casing, means including a conduit interconnecting the casing and the induction passage beyond the throttle valve and a pressure responsive member in the conduit to vary the position of the choke valve.

38. In combination with an internal combustion engine, a carburetor having a throttle and a pressure responsive choke valve, temperature responsive means for yieldingly urging the valve toward closed position and rendered inoperative at high temperatures, and means responsive to suction posterior to said throttle for moving the valve toward open position against the force of said temperature responsive means, and means whereby said choke valve will be moved to its full open position irrespective of said suction responsive means.

39. In combination with an internal combustion engine, a carburetor having a choke valve, temperature responsive means yieldingly urging the valve toward closed position at low temperatures, additional means resisting opening movement of the valve, and suction operated means operative to render said additional means inoperative and to move the valve to at least partially opened position against the force of the temperature responsive means, 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.

40. In combination with an internal combustion engine, a carburetor having a throttle and a pressure responsive choke valve, means operative below a predetermined temperature to yieldingly urge the valve toward closed position, additional means resisting opening movement of the valve, and means responsive to a predetermined suction posterior to the throttle for rendering said additional means inoperative and for moving the valve to at least partially opened position against the force of the temperature responsive means, 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.

IRVEN E. COFFEY.