USRE20112E - Automatic fuel regulator - Google Patents

Description

Sept. 15, 1936.

c. sToKEs AUTOMATIC FUEL REGULATOR Original Filed Sept. l, 1927 3 Sheets-Sheet 1 sept. 1 5, 1936-. CY STKES Re. 20,112

AUTOMATIC FUEL REGULATOR original Filed sept. 1,'192'7 5 sheets-sheet :2L

Reissued Sept. 15, 1936 UNITED STATES PATENT OFFICE l AUTOMATIC FUEL REGULATOR Original No. 1,841,687, dated January 19, 1932,

Serial No. 216,918, September 1, 1927.

Application for reissue January 18, 1934, Serial-No.

36 Claims.

This invention relates to improvements in automatic fuel regulation for internal combustion engines.

The principal object of the invention is to provide automatic control of the fuel supply from a carbureter to an internal combustion engine to which the carbureter is attached.

Another object of the invention is to provide automatic fuel regulation through a carbureter to an engine controlled by thev heat of the engine.

Another object is to provide automatically controlled choking and/or priming means for a. carbureter.

Another object is to provide automatic control of the main throttle valve of a carbureter at starting.

Another object is to provide a thermostatically controlled carbureter for aninternal combustion engine.

Another object is to provide a thermostatically controlled means of regulating the supply of fuel and air to an engine.

Other objects will become apparent as my invention is more fully disclosed herein.

Referring to the drawings, wherein the same numbers indicate like parts:

Fig. 1 is a plan view of a carbureter.

Fig. 2 is a section along the lines 2 2 of Fig. 1.

Fig. 3 is a section of part of Fig. 2.

Fig. 4 is a modification of part of Fig. 2.

Fig. 5 is a section along the lines 5 5 of Fig. 2.

Fig. 6 is a section along the lines 6-6 of Fig. 5.

Fig. 7 is an alternative for part of Fig.` 5.

Fig. 8 is a detail of improved construction for application to Figs. 1, 2, 5, and '7.

Fig. 9 is an alternative for Fig. 8.

Fig. 10 is a section along the lines I 0--I0 of Fig. l.

Fig. 11 is a view along the lines II-II of Fig. 10.

Fig. 12 is a view along the lines I2-I2 of Fig. 10.

Fig. 13 is a side view of amodication of Fig. 1.

Fig. 14 is a view of the carbureter attached to an internal combustion engine.

Fig. 15 is a section along the lines I5-I5 of Fig. 14.-

Fig. 16 is an alternative to part of Fig. 14.l

Fig. 17 is an alternative to part of Fig. 14.

Fig. 18 is a view of part of Fig. 17.

An internal combustion engine I0 is provided With an inlet manifold II and an exhaust pipe A carbureter I3 is fixed to manifold II for supplying air and .fuel in regulated and variable (Cl. 12S-119) quantities to engine I0 responsive to the engine suction and a hot air stove I4 surrounds pipe I2 being connected by a flexible pipe I5 to the main air entry I6 of carbureter I3, air being admitted to the interior of stove through a port I'I. .Liquid fuel is supplied in any well known manner to carbureter I3 through a pipe I8, all as illustrated in Figs. 14 and 15.

Referring now to Figs. 1, 2, 3, 5, 6, 10, 11 and l2, carbureter I3 is provided With the usual constant level float chamber I9 which receives liquid fuel through pipe I8, the level of which is controlled by float 20 to which is attached a valve (not shown) governing the entry of pipe IB to chamber I9.

Carbureter I3 is attached to engine Ill and the engine suction draws air in through main air entry IE to a mixing chamber 2| where fuel is mixed therewith and supplied to engine I0 in regulated and variable quantities by a throttle valve 22. The main liquid fuel supply is drawn from chamber I9 through a port 23 to a regulating port l2li controlled by a needle valve 25 and thence through a passage 26 to a fitting 21 where it is mixed with a secondary air supply drawn through a passage 28 to a secondary mixing chamber 29 and discharged through main nozzle 30 to the main mixing chamber 2|.

The discharge of nozzle 3II is set at the throat of a small Venturi tube 3I,`held in carbureter I3 by apart 32, and the discharge of venturi 3| is set at the throat of a large Venturi tube 33 the upper part of which forms the lower part,

of mixing chamber 2|. Secondary air is supplied to a passage 28 from air entry I6 through a port 34, the flow therethrough being governed by a valve 35 Working in a cylinder 36. Valve 35 is normally seated by spring 31 held in passage 36 by a plug 38 and is lifted from its seat by the engine suction applied to cylinder 36 through a port 39 on the engine side of throttle 22 and this suction can be regulated by a screw 40 controlling the entry of air through a port 4I in the form of an air bleed.

The usual idling mixture is provided by the supply of liquid fuel from passage 26 through a. passage 42 which leads to a discharge orifice 43 in the mixing chamber on the engine side of throttle 22, the admission of idling air being regulated by an adjusting screw 44 controlling the admission of air through a port 45, and the idling mixture is rsupplied only at such times as throttle 22 is substantially closed or as hereinafter described.

Throttle 22 is held in a spindle 46 which is journalled in the walls of carbureter I3, one end being surrounded by a sleeve 41 on which is pressed a throttle arm 48. A slot 49 is formed in spindle 46 to permit a certain degree of movement thereof with respect to throttle arm 48 and a pin 58 passes through arm 48, sleeve 41 and spindle 46 for transmitting motion from arm 48 to spindle 46, there being no lost motion between pin 58, arm 48 and sleeve 41.

To the opposite end of spindle 46 is attached a secondary throttle arm 5I, whereby a limited movement of spindle 46 and throttle 22 with respect to arm 48 may be effected at starting periods, the movement depending on the angularity in the walls of slot 49, and a starting lever 52 fastened by screw 53 to eiiect said movement initially. l

The other end of lever 52 rests on the upper part of a dashpot 54 containing a reciprocating piston 55 pressed on a stem 56. The lower part of dashpot 54 is open to atmosphere through a port 51 and the under side of piston 55 is cushioned against a spring 58. Stem 56 is hollow and a plurality -of ports 59 through the walls thereof connect the space between the upper side of piston 55 and the upper wallof dashpot 54 with air passage I6; dashpot 54 being threaded at its lower end to screw into a boss 68.

This last end of spindle 46 passes through the upper part of an accelerating well 6I containing a tube 62 lopen at its lower end to receive liquid fuel through a passage 63 from chamber I9 and its upper end connecting with a passage 64, and a minute orifice 65, to mixing chamber 2| on 'the engine side of throttle 22. Tube 62 is xed at its upper end in the casting to have an annular space 66 therearound connected to atmosphere by a port 61 and through a passage 68 in part 32 to a discharge orifice 69 in venturi 3|, it being here noted that port 61, passage 68, orifice 69, nozzle 38 and air port 34 are all above the normal constant liquid level X-X in fioat chamber I9.

A choke valve 18 is mounted off center in passage I6 on a spindle 1 Lhaving its ends journalled in bosses 12 and 13.. Boss 13 is encircled by a casing 14 adjustably held thereon by a screw 15 working in a slot 16 and having its outer end closed by a cover 11. Interiorly of casing 14 is a bimetallic thermostatic spring 18 having one end ailxed in a slot in spindle 1 I, the other end being fastened to casing 14 by bolt 19 and nut 88. A regulating disk 6I, xed to spindle 1I, serves to open and close a passage 82 connecting the invterior of casing 14 with passage I6 through boss 13 onvthe engine side of choke valve 18, the opening and closing being effected by the relative position of a slot 83 cut in disk 8|. A second passage 84 serves to connect the interior of casing 14 with 'airpassage I6 on the atmosphere side of choke valve 18 being continuously open by means of a slot 85 cut in disk 8.I, its other end terminating in `animpact pipe 81 having its atmosphere vside cut away at 86 and standing to such a height in passage I6 as to form a stop for choke valve 18 when wide open and in a horizontal position. The upper part of accelerating well 6I has passage 64 therein connected to atmosphere through passage 88 closed by a plug 89 having an orifice of preldeterminedsize therein to regulate the height to -is substantially unrestrictedly open, throttle 22 is held closed at idling position by a spring 98 fastenedyto one end of a cross bary 9i extending across the cover of float chamber I9, a second spring 92 fastened to the opposite end of bar 9I serving to apply the proper tension to arm 48 for holding throttle 22 at idling position. Float chamber I9 is open to amospheric pressure through a port 93.

The operation of the devices already illustrated and described when attached in operative position to an internal combustion engine is as follows:

If it be assumed that engine I8 is cold and at low temperature thermostatic spring 18 will be contracted to hold choke valve 18 closed in passage I6 except for a very slight leak around the periphery of valve 18. Throttle 22 is held closed at idling position. Upon cranking engine I8, the suction thereof is transmitted past throttle 22 through stem 56 and holes 59 to the upper part of piston 55 whereby the same is raised thereby lifting lever 52 and opening throttle 22 a predetermined amount against the resistance of spring 98. The amount of opening of throttle 22 will be determined by the degree of angularity of the walls of slot 49 in spindle 46. In this manner a comparatively high suction is applied to nozzle 38 for drawing therethrough a rich priming charge of liquid fuel which is unmixed with air in fitting 21 because -substantially the same vacuum 'exists at nozzle 38 as there is at port 34 when choke valve 1n is closed. At the same time a umited amount of air and liquid fuel is supplied through orifice 43. This rich priming charge, which isdue to the limited amount of air passing choke valve 18, is drawn into the cylinders of engine I8 by its suction until the mixture isignited therein, whereupon a sudden increase in vacuum takes place in mixing chamber 2| because engine I8 will be then idling at increased idling speed over cranking speed and this increase in vacuum causes a partial opening of choke valve 18 against the resistance of thermostatic spring 1B because of the difference in pressure now exerted on opposite sides of valve 18, valve 18 being mounted on spindle 1I oi' center in passage I6.

Throttle 22 being held open beyond normal idling position a predetermined amount by lever 52, engine I8 runs at a fast rate because it is necessary to idle fast at low temperatures and the engine .vacuum is applied through passage 82 to the interior of casing 14 whereby heated air is drawn thereto from stove I4 through pipe I5, pipe 81 and passage 84, it beingnoted that at cranking speeds passage 82 is entirely closed by disk 83 so that the highest effective Vacuum will be applied for drawing in a rich priming charge from nozzle 38, the sudden increase in vacuum upon the engine I8 firing causing the initial partial opening of passage 82 whereby heated air will commence to be drawn therethrough. With continued running of engine I8, the air drawn through casing 14 and over thermostatic spring 18 therein will cause continued expansion of said thermostat thus causinga gradual and continued opening of choke valve 18 and a gradual and continued decrease of vacuum applied to the top of piston 55 whereby spring 98 gradually closes throttle 22 until the proper optimum engine operating temperature is reached when throttle 22 will be at its normal slow idling position. At such time idling mixture will be drawn solely through port 43.

During all idling periods when throttle `22 is closed, the idling vacuum will befapplied through the small orifice 39 to the top of valve 35 thus raising the same from its seat in passage 28 against the resistance of spring 31, but this raising of valve 35 does not become fully effective until choke valve 10 is at least partially open whereby sufficient difference in pressure will exist between the upper and lower sides of the head of valve 35 to raise the same.

Also such idling vacuums are applied through the small port 65 to be applied to tube 62 whereby liquid fuel is raised therein to a predetermined height below the level of spindle 46, said height being determined by the size of 'the -air bleed passage 88, the highest position of the liquid column in tube 62 being when throttle 22 is closed for idling speeds.

Now upon opening throttle 22 to any degree for increased speed of engine I0 (valve 10 being open), the vacuum on the engine side of throttle 22 will decrease while the vacuum in mixing chamber 2| will increase to the end that no mixture will be drawn through orifice 43 but mixture will be drawn in the properamount and proportion from nozzle 30, the volume being governed by the degree of engine suction, applied and intensified through the action of the venturis 3| and 33, and the proportion of air to liquid fuel being controlled in the initial opening stage of throttle 22 by the action of valve 35.

Valve 35 is arranged to be seated in passage 28 and cut oif the supply of air therethrough when throttle 22 is aboutl one-quarter open except for a very small amount `which may pass through a calibrated orifice 34a therein. This supply of secondary air mixing in fitting 21 through a plurality of ports 21a gives fine atomizing eects on the liquid fuel supplied through passage 26 and also regulates the effect of the suction applied through nozzle 30 so that proper and economical proportions are maintained in the mixture atall operating speeds and loads other than idling.

The passage of air from passage I6 through port 34 and passage 28 to the secondary mixing chamber 29 will be better understood when it is explained that passage I6 is normally of greater diameter than mixing chamber 2|. Also any vacuum induced at the throat of venturi 3| will be greater than the vacuum in passage I6 at any engine speed., therefore there will always be a circulation of air from passage I6 through port 34 and passage 28 to the nozzle 3|). Anequivalent effect for air bleeding nozzle 30 may be obtained by closing the port 34 to passage I6 and transferring the position of the same to a wall ofcylinder 36 where it will open to air on the lower side of the head of valve 35, but the present and described location of port 24 is preferred because at starting periods there will be no flow of air from passage |6, thus leaving the rich priming charge from nozzle 38 undiluted.

The discharge of liquid fuel from accelerating well 6| occurs at the continued opening of throttle 22 but is particularly effective upon the sudden opening oi' throttle 22 from closed to open position. When this occurs, the vacuum at port 65 will drop from say 22 inches of mercury at idling to one-half inch of mercury at wide open throttle. This causes the column of liquid fuel held in tube 62 to fall and flll the annular space 66 above the level of the passage 68 a predetermined distance so that the excess above that level will discharge through orifice 69 to there mix with the air stream now passing at high velocity through venturi 3|. In this manner the inertia of the liquid fuel supplied through passage 26 is compensated formomentarily.

During normal running there may be insufcient difference in vacuum on either side of choke valve 1|) to cause a diversionv of sumcient heated air around thermostat 18 and for this reason standpipe 81 is provided with one edge cut away at 86 to receive the impact of the air stream, thus forcing the heated air through casing 14 to act on thermostat 18 and hold valve 18 open, the limit of opening being its horizontal position when one side thereof rests on the top of pipe 81. v

At low temperatures and after starting as described, if it be desired to accelerate, increased richness of mixture is provided for because of the partially closed position of choke valve 18 thus throwing abnormal suction on nozzle 30 until engine Il) approaches optimum temperature conditions when valve 18 will be further opened and the abnormal suction on nozzle reduced.

With certain types of engines, the priming charge induced through nozzle 30 as already described is insufficient for the quickest and most desirable start and therefore, in addition to the choking means already described, further priming means are provided more particularly illustrated in Figs. 8 and 9. In Fig. 8, a lever 94 is fastened to spindle 1| at one end, the other end supporting a valve 95 adapted to be resiliently seated in passage 88 by the pressure of a spring 96, this being in order that choke valve 10 may be fully closed as well as valve 95. When this happens at starting periods, atmosphere is cut olf from passage 88 by valve 95 to the end that a high cranking vacuum is applied to through orifice 65 and a stream of liquid fuel is drawn therethrough from tube 62. This additional stream of fuel'aids the quick starting of engine I8 and after starting valve 95 still is held closing passage 88 because of a certain amount of lost motion between the end of lever 94 and the head of valve 95.

Thus additional fuel is supplied for starting and for running for a limited time thereafter until the continued opening of choke valve 10 causes lever 94 to engage the, head of valve 95' and start to open passage 88. This action reduces the amount of fuel drawn through orifice 65 because air is now being admitted to passage 88 until passage 88 is wide `open at optimum operating temperatures.

Another function of valve 95 is to be noted. While fuel is .being drawn through orice 65, as described, the liquid level in tube 62 will be raised above normal so that when throttle 22 is suddenly opened at subnormal operating temperatures, an additional amount of accelerating charge will be supplied from well 6| to orice 69.

An alternative construction is shown in Fig. 9, wherein a thermostatic spring encircles valve 95, being held in spaced relation to the head thereof by a nut 98. Thermostat 91 is responsive to the heated air surrounding engine l0, more particularly when the same is placed under the hood of an automobile, and operates to open valve 95 with increasing temperatures of engine i6.

A modification of dashpot 54 is shown in Fig. 4, wherein choke valve 18 is placed in the center of passage I6 and holes 59 extend up to the head of stem 56. At starting, therefore, valve 1li will be tightly closed and the engine suction will raise piston 55 and lever 52 a predetermined distance until certain of the holes 59 will be exposed to atmosphere thereby breaking the vacuum applied through stem 56 to the upper part of piston 55 until equilibrium is reached.

I'he air thus supplied through stem 55 to passage I0 takes' the place of that supplied by the sudden jump of valve 10 when the same is placed off center and, as valve 10 now gradually opens with increasing temperatures, piston 55 will gradually fall and cut oiI more of the holes 59 until all are cut off from atmosphere at optimum operating temperatures.

Fig. rI shows an alternative construction for the upper part of Fig. 5 wherein throttle arm 48 is firmly fastened to spindle 45 and spindle 46 supports lever 52 on the same side as arm 4B. The tension of spring 92 is now so calibrated as to permit the limited opening of throttle 22 at starting as already described for fast idling and this construction permits the easy installation of apparatus shown in Fig. 8, if so desired.

Fig. 13 shows a modification of Figs. 5 and '1 wherein a lever 99 is fixed to spindle 1| and connected by a link |00 to a lever |0| fastened centrally to spindle 46. Link |00 has a head |02 sliding through a slot |03 in lever |0| and held therein by a. pin |04 which is adapted to hold on lever I0| at starting periods for opening throttle 22 a predetermined amount against the re' sistance of a spring |05, said spring holding throttle 22 closed at idling position at optimum operating temperatures.

When choke valve 10 is closed, the action of thermostat 18 will cause link |00 -to pull on lever |0| to hold throttle 22 open a certain distance for fast idling, thereafter as the temperature of engine I0 increases, valve 10 will gradually open and permit throttle 22 to gradually close. At any time throttle 22 may be fully opened, irrespective of the position of valve 10 because link |00 can freely slide through slot |03.

Fig. 16 shows a modification of Figs. 15 and 14. wherein the stove i4 is connecte-d by a comparatively small pipe l5 to the interior of casing 14 thence to the manifold on the engine side of throttle 22. This construction is provided in such cases as when the carbureter I3 is not supplied with hot air when passages 02 and 84 are plugged and heated air is drawn over thermostat 1B through pipe I5. The entry of pipe I5 to manifold is through'a small orice about the size of a #70 drill when pipe i5 is one quarter inch internal diameter, but these comparative sizes may be varied with the capacity of engine I0 so as not to affect the idling mixture.

Figs. 17 and 18 show an alternative construction for Figs. 14, 15 and 16 wherein the heated exhaust gases are conveyed` by Atheir pressure from the interior of pipe |2 through pipe I5 to the interior of casing 14 wherein they heat thermostat 18 and pass to atmosphere through a plurality of holes |08, the entry of pipe I5 in exhaust pipe |12 facing in the direction of the flow of exhaust gases therethrough.

The entry of pipe I5 to casing 14 is controlled by a sector |06, Ifastened to spindle 1|, having a tapered slot |01 therethrough to the end that pipe |5 may be fully opened to casing 14 at idling speeds and thereafter will be gradually reduced in opening at higher speeds when the exhaust gases are at a higher temperature. This action prevents excessive strains being applied to thermostat 18, due to excessive heat at high speeds.

By the various ldispositions and constructions shown and described, it will be seen that a very rich mixture will be drawn into engine- I0 initially by its suction, both Kby priming and choking. suddenly reduced to a rich mixture after tiring and thereafter gradually reduced to normal as engine |0 arrives at normal and opti.- mum operating temperature. The additional priming charge for starting is provided through orice 65, which may vary in size for automobile engines from a #70 to a #60 drill hole, while the choking means causea restriction in the supply of air as well as increasing the flow of fuel from nozzle 30. In the present case it will be seen that the additional priming supply may be dependent on the action of the choking means.

For any particular engine |0, the tension of spiral thermostatic spring 1B may be adjusted by loosening screw 10 and turning casing 14 until choke valve 10 is in the proper position when screw 'I9 is again made tight.

I claim:

l. In a carbureter for supplyinga mixture of air and fuel to a connected internal combustion engine, a throttle for controlling the mixture, means normally tending to close the throttle, and suction operated means and means controlled thereby for partially opening the throttle when starting the engine.

2. In a carbureter for supplying a mixture of air and fuel to a connected internal combustion engine, a throttle for controlling the mixture, means normally tending to close the throttle, means actuatedby the engine suction and means controlled thereby for maintaining the throttle slightly open when starting the engine.

3. In a suction operated carbureter, a main air passage having a throttle therein, a discharge passage having a throttle therein, a fuel supply passage discharging between said throttles and means connected between said throttles and effected by engine suction for .automatically opening the discharge throttle.

4. In a suction operated carbureter, a main air passage having a throttle therein, a discharge passage having a throttle therein, a fuel supply passage discharging between said throttles and suction operated means connected between said throttles and means controlled thereby for automatically opening the discharge throttle.

5. In a carbureter for supplying a mixture of air and fuel to a connected engine by its suction, a discharge throttle, means normally setting the discharge throttle to supply a minimumvolume of said mixture to the engine when idling, suction operated means and means controlled thereby to open said throttle to automatically increase the volume of said mixture when starting the engine.

6. In a carbureter for supplying a mixture of air and fuel to a `connected engine by its suction, a discharge throttle, means normally setting the discharge throttle to supply a minimum volume of said mixture to the engine when idling, suction operated means and means controlled thereby to open said throttle to automatically and temporarily increase the volume of said mixture when vstarting the engine.

'1. In a carbureter for supplying a mixture of air and fuel to a connected engine by its suction, a discharge throttle normally set to supply yclicking throttle in' the air passage, a mixing chamber, a discharge throttle governing thedischarge from the mixing chamber, a fuel nozzle discharging into the mixing chambenand means dependent on the closing of the choking throttle and effected by engine suction for opening the discharge throttle.

9. The combination of an internal combustion engine having a passage for supplying fuel and air thereto, means to supply fuel and air to the passage, a throttle in said passage governing the supply of said mixture, and suction operated means actuated by engine suction and means acted upon by enginetemperature to effect said suc- Ition means for varying the position of said throttle. l

10. The combination of an internal combustion engine, a carbureter, a passage through the carbureter for supplying the engine with a mixture of fuel and air by engine vacuum, a. nozzle discharging into said passage, means to supply fuel to the nozzle, a throttle in the passage posterior to the nozzle, an anterior throttle in the passage, and means associated respectively with said posterior and anterior throttles and dependent on the vacuum between said throttles for varying the position of both throttles.

11. The combination of an internal combustion engine, a carbureter, a passage through the carbureter for supplying the engine with a mixture of fuel and air by engine vacuum, a nozzle discharging into said passage, means'to supply fuel to the'nozzle, a throttle in the passage posterior to the nozzle, an anterior throttle in the passage, and means associated respectively with said posterior and anterior throttles and dependent on the vacuum between said throttles and on engine temperature for varying the position of both throttles.

l2. The method of regulating the supply of fuel and air to an internal combustion engine which comprises supplying aV very rich mixture of comparatively large volume to the engine by its vacuum at starting, firing the mixture whereby a sudden increase in vacuum occurs, then utilizing the sudden increase in vacuum to suddenly decrease the richness of the mixture and thereafter gradually decreasing the volume supplied while decreasing the proportion of fuel to air according to engine suction.

13. The method of regulating the supply of fuel and air to an internal combustion engine which' comprises supplying a very rich mixture of comparatively large volume to the engine by its vacuum at starting, firing the mixture whereby a sudden increase in vacuum occurs, utilizing the sudden increase i vacuum to initially decrease the richness of the mixture and thereafter utilizing the engine temperature to gradually decrease the volume supplied and to further decrease the richness of the mixture while,` decreas- -ing the proportion of fuel to air. l

14. The method of regulating the supply of fuel and air to an internal combustion engine which comprises'suppl'ying a mixture of fuel and air to the engine in comparatively large volume, the proportion of fuel to air being comparatively high, then gradually reducing the volume supplied while reducing the proportion of fuel to air according to the engine suction.

15. The method of regulating the supply of fuel and air to an internal combustion engine which comprises supplying a mixture of fuel land air to the engine in comparatively large volume,

the proportion of fuel to air being comparatively y.

high, then gradually reducing the volume supplied while reducing the proportion of fuel to air according to the engine temperature.

16. The method of regulating` the supply of fuel and air to an internal combustion engine which comprises supplying a mixture of fuel and air to the engine in comparatively large volume, the proportion of fuel to air being comparatively high, then gradually reducing the volume supplied While reducing the proportion of fuel to air according to thel engine suction and temperature.

1'7. A carbureter having a constant level fuel supply chamber, a mixing chamber, means to supply air to the mixing chamber, a throttle governing the discharge from the mixing chamber, a well fed with liquid fuel from the supply charnber and discharging into the mixing chamber, means connected with the mixing chamber on one side of said throttle to raise the liquid level in the well above the constant liquid level in the chamber, and means to automatically vary the liquid level in the well depending'on temperature.

18.v A carbureter having a constant level fuel supply chamber, a mixing chamber, means to supply air to the mixing chamber, a throttle governing the discharge from the mixing chamber, a well fed with liquid fuel from the supply chamber and discharging into the mixing chamber, means connecting with the mixing chamber on one side of said throttle to raise the liquid level in the well above the constant liquid level in the chamber, and means to vautomatically vary the liquid level in the well and discharge the liquid fuel therein to the mixingv chamber on either side of said throttle.

19. In a plain tube carbureter, means forming a mixing conduit, an air inlet and a fuel inlet for said mixing conduit, an air inlet valve mounted in said air inlet, said air inlet valve being so mounted as to be openable in response to suction, a heat responsive device for yieldably closing said valve when the temperature is below normal, said heat responsive device being constructed and arranged to hold said valve in a fixed open position regardless of variations in suction whenever the temperature is at or above normal.

20. In a carbureter, means forming a mixing conduit, an air inlet and a fuel inlet for said mixing conduit, a choke valve, said fuel inlet discharging into said mixing conduit at a point posterior to said choke valve, said choke valve being concentrically mounted in said air inlet whereby it may be moved toward open position by suction, and a heat responsive device for closing said choke valve when the temperature is below normal, said heat responsive device being constructed and arranged to permit the movement of said choke valve to fully open position whenever the temperature is at or above normal, said choke valve remaining in fully open position regardless of variations in either suction or temp'erature as long as the temperature does not fall below normal.

21. In a plain tube carbureter, means forming a mixing conduit, a single main air inlet and a fuel inlet for said mixing conduit, said air inlet being of constant size regardless of suction during normal temperature operation, a valve for controlling said air inlet to enrich the mixture whenever the temperature-is below normal, heat responsive means for operating said valve, said valve being constructed and arranged to be directly acted on by suction when it is in mixture-enriching position and being displaced by suction in a direction to cause a leaner mixture to be delivered by the carbureter.

22. In a carburetor, means forming a mixing conduit, said mixing conduit having an air inlet, a fuel inlet, and a mixture outlet, a manually operable throttle valve controlling said mixture outlet, a choke valve controlling said air inlet. a heat responsive device controlling the position of said choke valve, and means connected to said choke valve for preventing the movement of said throttle valve to fully closed position while said choke valve is in fully closed position.

23. In a plain tube carbureter. means forming a mixing conduit, said mixing conduit having an air inlet and a fuel inlet and a mixture outlet, a manually operable throttle valve controlling said mixture outlet, an eccentrically mounted choke valve controlling said air inlet, a heat responsive device for closing said choke valve when the temperature is below normal, said heat responsive device being constructed and arranged to permit the Ychoke valve to move to fully open position as soon as the temperature reaches normal and to remain in fully open position regardless of temperature variations above normal, and connections between said choke valve and said throttle valve for preventing the movement of said throttle valve to fully closed position as long as said choke valve is in fully closed position.

2'4. In a carbureter, means forming a mixing conduit, said mixing conduit having an air inlet, a fuel inlet and a mixture outlet, a manually operable throttle valve controlling said mixture outlet and a heat responsive device for interfering with the closing of said throttle valve when the temperature is below normal.

25. In a carbureter, means forming a mixing conduit, said mixing conduit having an air inlet, a fuel inlet and a mixture outlet, a manually operable throttle valve controlling said mixture outlet and a heat responsive device for at least partially opening said throttle valve when the temperature is below normal.

26. In a carbureter, means forming a mixing conduit, said mixing conduit having an air inlet, a fuel inlet and a mixture outlet, a choke valve controlling said air inlet and a throttle valve controlling said mixture outlet, a heat responsive device for controlling said choke valve, and a suction responsive device for controlling said throttle valve.

27. In a plain tube carbureter, means forming a mixing conduit, said mixing conduit having an air inlet, a fuel inlet and a mixture outlet, a throttle valve controlling said mixture outlet, a choke valve controlling said air inlet, means for operating said choke valve in response to heat and suction and for holding said choke valve in a fixed open position regardless of suction whenever the temperature is at or above normal, and means responsive to both heat and suction for controlling the position of said throttle valve.

28. Inan internal combustion engine having an intake manifold, and an exhaust manifold;

a carbureter having an air inlet and a fuel outlet, a, choke valve mounted in said air inlet, a throttle valve mounted in said outlet, said choke valve having a shaft, a heat responsive element mounted at one end of said shaft, a housing for said heat responsive element, a. passageway connecting said housing to said air inlet whereby at least some suction is applied to said housing, a conduit for conveying heated gaseous fluid from said exhaust manifold to said housing, valve means controlled by said shaft for regulating the flow of said heated gaseous uid through said housing, and means operable from said shaft for preventing closing of the throttle valve.

29. In an internal combustion engine having an intake manifold andan exhaust manifold; a carbureter attached to said inlet manifold, said carbureter having an air inlet, a fuel inlet and a mixture outlet, a throttle valve controlling said mixture outlet, a choke valve controlling said air inlet, a heat responsive element connected to said choke valve, a housing for said heat responsive element, an air heating stove mounted on said exhaust pipe, a conduit leading from said air heating stove to said housing, and another conduit leading from said housing to said intake manifold at a point posterior to said throttle.

30. In an internal combustion engine having an intake manifold and an exhaust manifold, a carbureter attached to said inlet manifold, said carbureter having an air inlet, a fuel inlet and a mixture outlet, a throttle valve controlling said mixture outlet, a choke valve controlling said air inlet, a heat responsive element connected t said choke valve, a housing for said heat responsive element, an air heating stove mounted on said exhaust pipe, a conduit leading from said air heating stove to said housing, and another conduit leading from said housing to said intake manifold at a point posterior to said throttle, and valve means operatively connected to said heat responsive device for controlling the flow of heated air through said housing.

31. In an internal combustion engine, an ini duction passage, a carbureter constituting part of said induction passage and having an air inlet and an air outlet, a choke valve mounted in said air inlet, a throttle valve mounted in said outlet, said choke valve having a shaft projecting from one side of said air inlet, a heat responsive ele ment mounted at said end of said shaft, a housing for said heat responsive element, a. conduit for conveying heated gaseous fluid to said housing to heat said element, said housing having an outlet to said induction passage posterior to said choke valve, and means controlled by said shaft for preventing closing of the throttle valve when starting the engine.

32. In an internal combustion engine having an induction passage and an exhaust manifold,

l a carbureter constituting part of said induction passage, a. choke valve in said carbureter, a throttle valve in said carbureter, said choke valve having a shaft, a heat responsive element at one end of said shaft, a housing for said heat responsive element, a passageway connecting said housing to said induction passage posterior to said choke valve whereby suction is applied to said housing, a conduit for conveying heated gaseous fluid from a point adjacent said exhaust mani--4 fold to said housing, and means operable by said heat responsive element controlling the closing of the throttle valve.

33. In a carbureter for supplying a mixture of air and fuel to a connected internal combustion engine, a, throttle for controlling the mixture supply, thermo-responsive means, and means controlled thereby for preventing closing of the` said means being controlled by the air intake throttle.

35. In a carbureter, a main air intake having a throttle therein, thermo-responsive means controlling said throttle, a discharge passage having a throttle therein, means operated by suction between said throttles, and means controlled thereby for preventing closing oi' the discharge throttle, and a' fuel supply e discharging 10 between said throttles.

36. In a carbureter for an internal combustion engine, a discharge valve normally set to supply idling mixture when the engine is hot, a choke valve, thermo-responsive means controlling'said choke valve, and means having a.v free connection lwith one of said valves, and controlled by the choke valve to prevent movement of the discharge valve to ,normal hot idling position, while the engine is cold.

' CHARLES L. STOKES.

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