US1877117A

US1877117A - Carburetor

Info

Publication number: US1877117A
Application number: US457362A
Authority: US
Inventors: Arthur R Baker
Original assignee: IRA T SWARTZ
Current assignee: IRA T SWARTZ
Priority date: 1930-05-29
Filing date: 1930-05-29
Publication date: 1932-09-13
Anticipated expiration: 1949-09-13

Description

Sept. 13, 1932. R BAKER 1,877,117

CARBURETOR Filed May 29,1950 4 Sheets-Sheet 1 gwwmtop Ari/1W1). Baker Sept. 13, 1932. A. R. BAKER 1,877,117

CARBURETOR Filed May '29, 1950 4 Sheets-Sheet 2 gwuvntoz Ari/MPH. Ba lrer Sept. 13, 1932. v A. R. BAKER 1,877,117

CARBURETOR Filed May 29, 1930 4 Sheets-Sheet 3 Ari/21MB. Ba lr er Sept. 13, 1932. A BAKE-R 1,877,117

CARBURETOR Filed May 29, 1930 4 Sheets-Sheet 4 Patented Sept. 13, 1932 UNITED STATES PATENT OFFICE ARTHUB R. BAKER, F INDIANAPOLIS, INDIANA, ASSIGNOR TO IRA. '1'. SWART'Z, OF

INDIANAPOLIS, INDIANA cmnimmfon Application filed May 29, 1930. Serial No. 457,362.

This invention relates .to carburetors and a general object of the invention is to provide anew and improved carburetor.

Another object is to provide a carburetor 6 which will function eificiently with low grade gasoline or other motor fuel.

A further object is to provide a carburetor which will reduce excessive detonation when using low grade fuel and thus enable the operator to secure the same or better results with a. low I grade of gasoline than are secured by other carburetors with so-called high-test or anti knock gasoline.

A further object is to provide a carburetor in which detonation is reduced.

Other objects and advantages will become ap arent as the description proceeds.

eferring to the accompanying drawings, which are made a part hereof and on which similar reference characters indicate similar parts,

Figure 1 is a side elevation of the carburetor as normally mounted in operative position on an engine,

2 Figure 2, a view in elevation from the opposite side of that shown in Figure 1,

Figure 3, a view in elevation looking from the right, as shown in Figure 1,

Figure 4, a section on line 44 of Fig.

3, looking up,

Figure 5, a section on the same line looking down, as indicated by the arrows in Figure 3, Figure 6, a vertical section taken substantially on line 66 of Figure 2,

Figure 7, a section on line 77 of Figure 5, Figure 8, a. detail view of the throttle valve, Figure 9, a section on line 9-9 of Figure 7, Figure 10, a section on line 10-10 of Figure 6,

Figure 11, a section on line 11-11- of Figure 5, and

Figure 12, a modified form of gasoline metering valve.

In the drawings numeral 20 indicates the casing of the lower section and 21 the casing of the upper section of the carburetor. These are secured together by a bolt, a gasket 19 being secured between them to provide the necessary seal. The lower casing is provided with an enlarged air intake port 22, said intake port being provided with the usual choke butterfly valve 23 which valve is operated by a crank arm 24 having a pin 25 to which may be attached an operating lever. In place of the arm shown, any other suitable mechanism for operating the butterfly valve may be provided. The upper casin 21 has a flanged portion 26 by means 0 which the carburetor is attached to the intake manifold 27 on the engine. The casing 21 is provided with a port 28 to which is attached a pipe, not shown, leading from a sup-ply of fuel. The fuel entering through the port 28, drops into a pan 29 and when this is filled it overflows into a well 30 in which is a float 31,

said float being pivoted at 32 by means of an arm 33, said arm resting beneath a valve 34 which controls the gasoline port. The arm 33 is sufliciently resilient to take care of any pulsations of the engine without disturbing the valve 34. From the construction just described it should be evident that the float 31 will maintain a predetermined level of fuel in the well 30 since when the float rises, the

arm 33 pressing upwardly on the valve 34 will close the inlet port. Pan 29 has a hole drilled through the floor at 35 through which a tube 36 extends, the lower end of the tube being well down within the fuel well to draw fuel from near the bottom. A shoulder 37 the greater portion of the slot in the tube will be normally below the level of the fuel in the well, a portion of it will be above the level of the fuel, the function of which will be presently more fully explained. Surrounding the slotted tube is a sleeve 41 which is secured in the bore 39. This sleeve has a venturi 42 near its upper end. Within the lower end of the sleeve 41 is pressed a plate 43 which has walls 44 forming a cup into which the lower end of the tube 38 flips.

The sleeve 41 is provided with a number of ports 45. The tube 38 is secured in the upper casing 21 and connects with an air intake port 46 in the top of the casing. The

operation of the engine. A second object of having the slot in this position is that during low or idling speed there may not be sufiicient suction to draw the air through the fuel in which case it will be drawn from above the fuel through this slot The casing 21 is dome-shaped and the space 111 above the fuel provides a relatively large expansion chamber into which partly carburetted air expands, and in which its velocity is reduced to allow any liquid fuel to drop back into the body of the fuel in the pan.

The tube 38 not only functions to load the air with fuel vapor but serves also another purpose. Air is drawn down through this tube and passes up through the fuel. -As it passes up through the venturi at 42 it acts as a pump to force fuel up around the tube 38 and to deposit it in the pan 29.

The tube 36 is secured in the cover 21. This tube 36 enters through the port into a chamber forming the enlarged end of a bore 48 which extends through the casing 21. A sleeve 49 is threaded into the bore at 50. A tube 51 is also threaded at 52 into the bore and this tube is surrounded by and radially spaced from the tube 49. The tube 51 has a restricted opening 53 at its outer end and a valve rod 54 is positioned within the tube 51 and has a valve 55 positioned adjacent'the restricted opening 53. The end 55 which forms the valve is made of such a size as neatly to enter the restricted opening 53 and closeoff the opening without actually engaging a valve seat. The valve rod 54 is secured tov a bellows 56 which bellows in turn is secured to a nut 57 which is screw-threaded into the outer end of the bore 48. The end of the rod 54 is likewise screw' threaded at 58- to receive a screw cap 59 which cap is threaded within a bore in the nut 57- at 60. The purpose of the screw 59 is to move the rod 54 axially to adjust the size of the opening 53 around the end 55. As shown in Figure 10 the rod 54 is grooved axially to pro vide a passage for fuel between the rod and the tube 51. The threads 60 on the screw plug 59 must necessarily be of a dilferent pitch from the threads 58 on the end of the rod 54 so that when the screw 59 is turned in either direction there will be an axial movement of the rod 54. For example, assume that the threads on the plug 59 are 20 35 pitch threads and the threads on the rod 54 are 40 pitch threads, then one revolution of the screw 59 will move the rod 54 th of an inch. If, however, the threads 58 should be made right-hand threads and the threads 60 lefthand threads then one revolution of the screw 59 .would move the rod 54 axially f ths of an inch. A nipple 61 is screw threaded into the end of the bore 48 opposite the plug 57 and a cap or cup 62 is secured upon the end of this nipple. The cap or cup 62 will be positioned in the path of the exhaust manifold 108 from the engine so as to heat the fuel which passes from the tube 51. The heated mixture then passes around the outside of tube 49 and into a chamber 63 from which it passes into an axial bore 64 from which passage it passes through radial bores 65 over the edge of a cup 66. The fuel. passing over the edge of the cup 66 mixes with air coming in through the intake 22 from which it passes through the expansion chamber 67 through which it enters into the intake manifold 27 of the engine.

Extending up through the head 112 surrounding the axial passage 64 is an axial bore into the lower end of which is inserted a short tube 113, the lower end of which extends down within the dished portion of the cup 66. Under certain circumstances, as at slow or idle speeds, some portion of the fuel issuing from the nozzle 53 may fall into the cup 66 as a liquid. In case this happens such liquid fuel will be drawn up through and delivered into the stream of fuel-being drawn into the engine. This feature smooths out to a certain extent the running of the engine at slow or at idling speeds.-

A pipe 68 is secured to the air intake 22 in order to draw air from a point distant from the engine so as to insure that relatively unheated or normal air is drawn into the carburetor instead of the heated air adjacent the hot portions of the engine.

The suction through the passage 67 will create an aspirating effect around the cup 66 which in turn through the annular passage 69 will create a vacuum above the liquid surrounding the tube 38. This will create a suction down through the tube 38 and draw air through this tube which air will pass partly through the slot in the tube and partly through the end of the tube up through the fuel in the well. Air laden with a small percentage of fuel will therefore be drawn through a port 114 into the annular passage 69. This air will in turn create a suction through the restricted port 53 and draw fuel through the tube 36. As the fuel issues through the restricted nozzle 53 it will become heated by contact with and by heat radiated from the casing 62 which projects into the exhaust gases from the engine.

In Figure 12 is shown a modified form of valve. The end 115 of this valve is in the form of a disk? In carburetors now in use the fuel is raised from the fluid level to the jet a distance of th to th of an inch. This is due to the fact that there is only a very low suction created at the end of the-spray nozzle. In the carburetor forming the subject matter of this invention the liquid is raised approximately 1% inches. This is possible because of the fact that a relatively high suction is created at the spray nozzle in this carburetor. .Of course the fact that the fuel is raised a greater height than in other carburetors in and of itself is-relatively unimportant but the fuel is raised this height because ofthe relatively high suction which is created at the spray nozzle 55. This high suction serves to more completely atomize fuel than is possible in other carburetors. The high suction claimed is brought about by a combination of the following operations The cold air which is drawn through the pipe 68 travels through the Venturi throttle valve and past the cup 66. When the throttle is wide open there is a large volume of air passing through the carburetor, although at a relatively low velocity. The restriction between'the venturi and the cup 66 increases the velocity, however, sufiiciently high to create a relatively high suction through the ports 65, this suction pressure being transmitted to the end of the annular passage 69 around the nozzle 53. The volume of air issuing through the axial passage 63 caused by this suction serves in turn to reduce the pressure at the nozzle 53 to create an additional high suction through the tube 51. This suction, of course serving to draw the fuel from the well up through the tube 36. It will be apparent therefore that the suction created at plus the suction created at 53 causes a relatively high suction to the fuel which is drawn through the tube 36 which of course makes it possible to elevate the fuel to a much higher level than was possible with the older carburetors. One result of the high suction at the nozzle 53 is to atomize the fuel as it issues from this nozzle into the hot cap 62, and to more thoroughly mix the fuel and air at this point.

Shown in detail in Figure 8 is the Venturishaped throttle valve, this consists of a sleeve 70 slidably positioned within the bore 71 and is guided by an arm 72 which slides on the lower end of a rod 73 which depends from the cup 66. The upper end of the cup 66 is screw threaded at 7 4 within the passage 63. The purpose of this threaded engagement is to provide means for adjusting the cup 66 for a purpose which will later appear.

The sleeve 70 may be provided with a packing ring 75. The upper inner end of the sleeve 70 is tapered as shown at 76. Vertical adjustment of the sleeve 70 will control the opening between the tapered side 76 of the sleeve and the edge of the head 112 to control the amount of fuel which may pass to the engine. The sleeve 70 is shaped with a shoulder portion 116 which cooperates with a tapered lower side 117 of the cup 66. In operation when the sleeve is in its partially closed posi-' tion the air stream is deflected radially by the taper 117 to create a suction between the head 112 and the cup 66. When the sleeve 70 is Wide 0 en the incoming air has a more direct path t rough the venturi. There is now,

however, a larger volume of air passing through the valve. This is deflected radially by the taper 116 into the enlargement around the head to create a strong suction through the annular nozzle between the cup 66 and head 112. The cup 66 preferably will. be adjusted so as to provide entrance of the necessary fuel to the engine during idling speed when the throttle is normally closed.

The rod 73 may be manually rotated by means of a Wing nut 96, or other means clamped to it so as to adjust ,the cup 66 with respect to the head 112.

l/Vhen the sleeve 70 is pushed down sufliciently far its lower end engages a disk 77 to which is attached a valve 78. The valve is normally closed by a spring 79, as shown in detail in Figure 7. The valve 78 controls passage of fuel from the pan 29. An air port 80 is drilled through the side of the casing and connects with an annular passage 81 around the valve. The valve is provided with a tube 82 through which the fuel entering through the valve 78 and the air which mixes with it from the port 80 enters within the venturi. When the throttle is open wide therefore the venturi gives an increased supply of fuel with a mixture of air as just described. The suction past the tube 82 will create suction to draw the fuel and air into the fuel charge. The arm or bracket 72 has a pair of curved portions 83 which fit in an annular groove about the venturi. The arm 72 is provided with a screw-threaded hole 84 to receive the end of an operating pin 85.

Positioned beneath the valve 78 is a piston I 86 which is provided with an axial bore 87 which is normally closed by a ball or other suitable valve 88. The spring 79 is seated upon a plate 89 pressed within the upper end of a chamber 90 formed in the upper end of the piston 86. The piston 86 in turn is slidable in'a casing 91, the lower end of which is provided with a port 92 which is also closed by ball or other valve 93. The valve93 controls entry of fuel through a bore 94 which bore is nects with a tube 95 which is bent over and the lower end terminates slightly above the bottom of the fuel in the pan 29. The pur pose of the bowed end 95 is to prevent fuel from freely flowing by gravity from the pan 29 through the valve 93 into the chamber beneath the piston 86. Should the fuel be allowed to flow freely by gravity a springpressed ball 92 might be necessary or at least a valve which was closed by some positive pressure means or else a much heavier ball valve than 93 would be required.

As shown at 110 in Figure 11 there is a sloping wall to the pan 29. The purpose of this is so that fuel will-be held in the pan when the car is on a steep incline. Without this inclined wall the fuel would flow to the low side of the carburetor so that none would be drawn into the engine when on a steep hill. In going down hill the operator frequently desires to accelerate the speed of the car near the foot preparatory to climbing another hill in front. Unless there were a wall such as 110 the fuel would all fall to the front of the carburetor.

The venturi which constitutes the throttle valve is operated by means of a toggle arrangement shown in Figure 2. This consists of an arm 97 pivoted on a screw 98 which is secured in the side of the casing 20. The arm 97 carried a pin 99 near its upper end to form a stop member. An arm 100 is rigidly secured to the side of the arm 97 and is provided with a ball 101 at its outer end to form means for attaching a lever thereto for operating the throttle.

A link 102 is pivoted to the arm 97 at 103 and is pivoted at its other end to the pin 95. To open the throttle the lever arm 100 is moved in the direction of the arrow shown in Fig. 2. As will be seen the first movement of this lever will move the throttle valve very slightly which in substance provides a lever having a rather high mechanical advantage .at the opening of the throttle with only a Adjustably mounted on the side of the intake manifold 27 is a rod 106. This rod carries on its lower end a wedge-shaped member 107 which fits between the side of the upper casing 21 and the exhaust manifold 108 of the engine. The purpose of the wedge 107 is to rovide means for controlling the amount of eat passing from the exhaust manifold to the body of the carburetor. A nut 109 may be provided for vertically adjusting the wedge. It should be apparent that when the wedge is tightly fitted between the exhaust manifold and the body of the carburetor that it provides a good heat conducting medium but when it is raised out of contact with these elements there is an air space betwen them which serves as a heat insulating medium. Under certain circumstances I may provide means for automatically adjusting the wedge as for example in response to temperature changes.

Operation The operation of the carburetor is as follows: Fuel is taken in through the line 28 and'drops into the pan 29 filling this pan up to the top of a wall over which the remaining fuel then spills into the well 30. The throttle valve 7 0 is depressed by means of the toggle mechanism shown in Figure 2. Upon the suction stroke of the engine air is drawn into the engine. This creates a suction around the cup 66 which suction together with the velocity of the air streaming past the cup creates a vacuum to draw air through the annular passage 69. The air enters this passage from the following courseFirst it comes into the casing through the air intake port 46 and passes down through the tube 38. Some of the air passes out through the slot 40 and up through the fuel in the well. Another and large volume of the air passes down through and out past the end of the tube 38 and up through the fuel during which course it takes up certain portions of the volatilized fuel. This air with its charge of fuel enters through port 114: into the annular passage 69 just mentioned. The velocity of the air traveling up around the tube 38. which velocity is increased by the venturi 42, acts as a pump to raise fuel from the well and deliver it into the pan 29. The velocity of the air together with the suction as the air passes out of the tube 51 creates suction within the tube 49 around the valve stem 54 to suck fuel through this tube. The fuel and the air become heated in the cap 62 which projects into the exhaust manifold of the engine. This is a mixture of fuel which is too rich to fire. This mixture, however, passes down through the chamber 63 and out through the ports 65 into the cup 66 where it is sucked and aspirated into the air which is being drawn in through the tube 68. This provides the normal fuel charge to the engine.

An analysis of the fuel charge in the cap 62 shows that an appreciable amount of noncondensable gas is present in the cap. Among these gases are carbon monoxide and hydrogen. The formation of these gases is due to the high temperature to which the fuel in the cap 62 is raised. The highly inflammable carbon monoxide and hydrogen are dispersed throughout the fuel and serve to conduct the ignition flames throughout the fuel charge.

Whenever the throttle is open it is desir= able to increase momentarily the charge of fuel delivered to the engine. This is provided by means of a plunger 86 which acts as a pump to inject a. small volume of fuel at each time the opening of the throttle is in creased. The mechanism for doing this is shown in detail in Figure 7 and consists of the plunger 86 operated in a cylinder 91. As the throttle is opened a bracket 120 on the arm 72, which normally supports the plunger 86 by means of a lug 121, allows the piston 86 to be forced down by the spring 79. As the piston is forced down fluid is forced out through the port 87 past the check valve 88 and out through the ports 118 into the main air stream where it is sucked into the engine. When the plunger 86 is raised again fuel is drawn into the cylinder 91 again so that this cylinder is kept filled with fuel. It is desirable at relatively high speeds to increase the supply of fuel delivered to the engine. Mechanism for doing this is shown in detailin Fig. 7. When the throttle 7 O is opened very wide the velocity of the air drawn past the cup 66 is decreased, this would tend to decrease the aspirating effect upon the gas and air being drawn in from the chamber 64. The lower end of the venturi 70, however, when this venturi reaches a certain predetermined level, strikes the disk 77 and opens the valve 78. This allows fuel to flow by gravity from the pan 29 through tube 82 within the venturi. The fuel as it flows through this valve is mixed with air which is drawn in through the radial port 80, the air entering through this port sufliciently volatilizes the fuel to make it easily drawn into the venturi where it is mixed with other air being drawn in through the port 22. Should the valve 78 be held open for any reason after the car comes to a stop it should be evident that a certain amount of fuel will leak out, only that in the pan 29, however, will leak out.

As stated in the objects of the invention one of the purposes sought to be accomplished by this carburetor is to secure the same re sults with low test gasoline or other fuels as are being secured by the so-called anti-knock or doctored fuels. This is done by delivering to the engine a fuel which is thought to have a rather dense or fog-like supply of vapor which is not readily explosive but rather which will be burned in the engine as it becomes ignited by the gases which are explosive. This supply of dense vapor is thought to be delivered to the engine for the following reasons:

The high velocity of the air which is drawn through the passage 69 carries with it a relatively large volume of fuel drawn in through the nozzle 53. This fuel and the air are heated to a relatively high temperature in the tube 62. The amount of fuel taken up by the air is somewhat in excess of the amount that will be readily vaporized when the whole comes in contact with the cold air drawn in through the pipe 68, i. e. when the whole supply has been reduced to a low temperature by the cold air from 68 some of the fuel will be in suspension in the air somewhat as a fog. This fuel will be drawn into the engine and will supply a slow-burning fuel charge in the engine. The burning of this fuel charge will develop power during the stroke of the piston rather than forming a part of an instantaneous explosion, i. e. the pressure within the cylinder will gradually increase as the fuel charge burns in a manner somewhat analogous to the burning of a charge in a cannon in which the powder charge continues to develop pressure until the shot has reached the mouth of the cannon. It will therefore be seen that if the above theory is correct the pressure in the cylinder is maintained for a longer periodduring the stroke of the piston than is true with fuels which explode instantly. It should be obvious furthermore that the detonation will be considerably decreased. One fact which assists the air which is drawn through 69 in becoming so well saturated with fuel is the fact that this air is drawn or bubbled through the fuel in the well and takes up a certain amount of the more highly volatile fuel so that the air enters the tube 62 with a certain amount of fuel which has been taken aboard so to speak, at a relatively. low temperature. This then when heated in the tube 62 will become more heavily laden with fuel than Would otherwise be the case, or in other'words, it would require a. higher temperature in the tube 62 to enable a given quantity of air to take up the desired amount of fuel.

It should be noted from the description and from the operation just given that the fuel is aerated through all of its movements in the carburetor as well as being churned up and thus aerated in the fuel pan and well. For example in the well it isaerated by the pumping action of the air which passes out through 38 up through the fuel. Thus the fuel is most completely aerated and then into a stream which ultimately issues into the stream of fuel going into the engine. This is an important fact for it means a more perfect fuel charge entering the engine for the purpose in mind.

It will be obvious to those skilled in the art that various changes may be made in my device without departing from the spirit of the invention and therefore I do not limit myself to what is shown in the drawings and described in the specification, but only as indicated in the appended claims.

Having thus fully described my said invention, what I claim as new and desire to'secure by Letters Patent, is:

1. A carburetor comprising a casing having an inlet for fuel and one or more inlets for air, a fuel well and a fuel pan in said casing means for replenishing the pan with fuel from the well, said pan being positioned so that the fuel first enters into it and overflows into the well, a-float in said well for controlling the admission of fuel into the casing, and means for drawing fuel out of the well and the pan and mixing it with carbureting air, substantially as set forth.

2. A carburetor comprising a casing having gasoline and air inlets, a gasoline well in said casing, a horizontal division in said casing, said division forming the floor of a gasoline pan, a pipe for gasoline and a pipe for air positioned in said floor and extending down into the gasoline within the well, means for drawing gasoline from the said well, and means for drawing air through the gasoline in the said well, and means for mixing the gasoline and air and delivering them to the suction line of a gasoline engine, substantially as set forth.

3. a A carburetor comprising a casing having gasoline and air inlets, a gasoline well in said casing, a horizontal division in said casing, said division forming the floor of a gasoline pan, a pipe for gasoline and a pipe for air positioned in said floor and extending down into the gasoline within the well, means for drawing gasoline from the said well, and means for drawing air through the gasoline in the said well, and means for mixing the gasoline and air and simultaneously heating them to a relatively high temperature, mixing therewith a relatively large volume of cold air and delivering the mixture to a gasoline engine, substantially as set forth.

4. A carburetor comprising a casing, a fuel well within said casing, a fuel pan adjacent said well, a portion of said well extending beneath said pan, a pipe extending into said well for drawing gasoline out of said well, a pipe extending through said pan into the fuel in said well for drawing air through the fuel, said last named pipe comprising a vertical tube in communication with the outside of said casing and extending into the gasoline in the well, said tube having an axial slot, the lower end of which is positioned beneath the level of the fuel whereby air may be drawn from without the casing through the tube and through the liquid gasoline to absorb the more easily volatilized elements of the gasoline, substantially as set forth.

5. A carburetor comprising a casing, a fuel well within said casing, a fuel pan adjacent said well, a portion of said well extending beneath said pan, a pipe extending into said well for drawing gasoline out of said well, a pipe extending through said pan into the fuel in said well for drawing air through the fuel, said last named pipe comprising a vertical tube in communication with theoutside of said casing and extending into the gasoline in the well, said tube having an axial slot, the lower end of which is positioned beneath the level of the fuel whereby air may be drawn from without the casing through the tube and through the liquid gasoline to absorb the more easily volatilized elements of the gasoline, means for conducting the said gasoline laden air through a spray nozzle and mixing it with a relatively large volume of gasoline to form a very rich gasoline mixture, and means for heating the mixture and for adding thereto a relatively large volume of cold air to form a correct fuel charge, substantially as set forth.

6. A carburetor comprising a casing hav ing an inlet for fuel and a plurality of inlets for air, means whereby the suction of the engine will cause the air to pull a charge of gasoline into its path to create a mixture which is too rich for complete combustion, means for heating the mixture of air and gasoline to a temperature above the ignition point of a normal fuel charge at the point of mixture and thereafter mixing with it a stream of cold air whereby a combination of explosive and slow burning fuel charge is formed, the fuel and air entering the heating means being in heat exchange relation with the outgoing fuel charge, substantially as set forth.

7. A carburetor comprising a casing having air and fuel inlets, means whereby the air inlet will carry a portion of gasoline into its path to form a fuel mixture which is too rich for complete combustion, means for heating this mixture of air and gasoline to a relatively high temperature at the point of mixture, means for delivering this heated mixture into another air stream which enters the carburetor, means for reversing the direction of flow of the fuel charge as it enters and leaves the heating means, the outgoing fuel charge being in contact with the incoming fuel and air whereby it is cooled by the incoming cool fuel and air, and manually operable means for injecting an additional stream of gasoline and air into the fuel charge previously formed whereby a richer fuel charge is pro duced, substantially as set forth.

8. A carburetor comprising a fuel chamber, an air passage to the engine, an air inlet to the fuel chamber said inlet delivering the air so as to cause it to pass through the fuel,

a hot chamber, a fuel and air inlet to the hot chamber, the contents being heated to a relatively high temperature and thereafter passed into the air passage leading into the suction of the engine, the casing of the hot chamber being positioned in axial alignment with the incoming fuel and air, the velocity of the liquid element of the fuel causing it to be projected against the surface of the said casing to heat and volatilize any liquid portions of the fuel, means being provided for reversing the flow of the fuel at the point of heating and bringing it in contact with the incoming fuel and air to heat the incoming fuel and air prior to its entry into the hot chamber, substantially as set forth.

9. A carburetor comprising a casing having liquid fuel and air inlets, the air inlet Q delivering the air so as to cause it to pass through the fuel, means for mixing air and gasoline in the casing to form a fuel mixture which is too rich for complete combustion, means for heating above the ignition point of a normally explosive charge to effect partial combustion and means for. regulating the heating means to vary the volume of the fuel charge therein and to control the temperature to which the fuel charge is raised,'a portion of the mixed air and gasoline, means for supplying a quantity of cold air to the firstnamed mixture, forming a slow burning fuel charge, substantially as set forth.

10. A carburetor comprising a casing hav ing liquid fuel and air inlets, the air inlet delivering air so as to cause it to pass through the fuel. for saturating air with gasoline in the casing, means for highly heating a portion of the mixed air and gasoline, means for supplying a quantity of cold air to the firstnamed mixture, said cold air forming a slow burning fuel charge, a throttle for controlling the passage of said fuel charge into the engine, and means whereby when said throt tle is opened to a predetermined extent an additional supply of gasoline is allowed to flow by gravity to the fuel charge, substantially as set forth.

11. A. carburetor comprisinga casing having an inlet for gasoline and a plurality of air inlets, means whereby the air through one of said air inlets Will aspirate gasoline into its path to form a fuel mixture which is too rich for complete combustion, a hot chamber positioned adjacent the exhaust from the engine and directly in the path of said exhaust whereby the fuel mixture is heated to a temperature above the ignition point of a normally completely expansive mixture, means for mixing the highly heated mixture of air and gasoline with relatively cold air, the cold air serving to condense some of the gasoline in the mixture to form' a slow burning fuel charge whereby a combustible but only partially explosive fuel charge is provided for delivery to the engine, substantially as set forth.

12. In a carburetor having an inlet for gasoline, a relatively large inlet for cold air, and a venturi throttle valve in said air inlet, a toggle for operating said throttle, a lever for operating said toggle, said lever serving to move said valve slightly at the beginning of its movement and increasing the amount of movement as the lever is moved, said venturi throttle valve being constructed so as to open against the engine suction and counter to the direction of flow of fuel into the engine, substantially as set forth.v E 13. In a carburetor having means for mixlets and means for mixing the air and fuel and having a hot spot for heating the mix- .ture, means for controlling the heat transmitted to said carburetor comprising a heat conducting block adjustably positioned to provide means for controlling the transfer of heat from the hot spot to the carburetor, substantially as set forth.

15. In a carburetor a throttle valve comprisinga stationary member forming a baffle plate, a movable sleeve, cooperating with the stationary member to control the size of opening of the throttle, said sleeve having a tapered inner side, and bein movable to gradually vary the space de ned by the tapered edge and the stationary member and so constructed that movement beyond a predetermined limit will increase the rate of opening caused by a given movement of the movable sleeve, substantially as set forth.

16. In a carburetor a throttle valve comprising a head having an axial gasoline port therein, a cup positioned adjacent said head, said cup having a tapered lower side, a sleeve having a tapered inner side, and a shoulder portion, said shoulder portion cooperating with the tapered portion of the cup to impart a radial movement to the air passing through the throttle, to create a suction on the gasoline issuing from the axial passage in the said head, substantially as set forth.

17. In a carburetor, a metering valve comprising a sleeve having a restricted opening, a stem slidable in said sleeve having its end adapted to control the size of the restricted opening, means for adjusting the said stem comprising a cap threaded on the stem and threaded on its exterior to adapt it to be screwed into a socket, said threads on the stem and those on the exterior of the cap being of a different pitch whereby rotation of the cap will move the stem axially, substantially as set forth.

18. A carburetor comprising a casing having an inlet for liquid fuel and an inlet for air the inlet for air causing the air to be delivered so as to pass through the fuel, means for mixing air and gasoline in the casing, means for creating a multiple suction on the gasoline and for spraying it through a restricted nozzle, the multiple suction effect serving to give the fuel a high velocity whereby it is highly atomized, and the heavier fuel elements are separated from the lighter ones and further atomized byreversing the direction of movement of the fuel charge, means for heating a portion of the mixed air and gasoline, means for supplying a quantity of cold air to the mixture, thus forming a slow burning fuel charge, substantially as set forth.

19. In a carburetor, a metering valve comprising a sleeve having a restricted opening, a stem slidable in said sleeve having its end adapted to control the size of the restricted opening, means for adjusting the stem comprising a cap threaded on the stem and threaded on its exterior but adapted to be screwed into a socket, said threads on the stem and those on the exterior of the cap being of a difi'erent pitch whereb rotation of the cap Will move the stem axial and a metallic bellows sleeve on said stem to provide against leakage about said stem, substantially as set forth.

20. A carburetor comprising a casing having a gasoline reservoir therein, an inlet for gasoline to said reservoir and an inlet for air, an outlet from said reservoir, a spraying nozzle in said outlet, a cap positioned on the easing and adapted to extend into the exhaust path of the gas from the engine, said spraying nozzle being positioned in the said cap and outside of said casing whereby the atomized gasoline alone is sub ected to the heat from the engine Without subjecting the remainder of tllile carburetor thereto, substantially as set fort 21. A carburetor comprising a casing having a gasoline reservoir therein, an inlet for a gasoline to said reservoir and an inlet for air, an outlet from said reservoir, a spraying nozzle in said outlet, a cap positioned on the cas ing and adapted to extend into the exhaust path of the gas from the engine, said spraying nozzle being positioned in the said cap and outside of said casing whereby the atomized gasoline alone is subjected to the heat from the engine Without subjecting the remainder of the carburetor thereto, and means for creating a multiple suction on the gasoline from the said reservoir to increase the velocity of the gasoline whereby it is more highly atomized, substantially as set forth.

22. A carburetor having a casing, a fuel Well and a fuel pan in said casing, means for supplying gasoline to said Well and from said well to said pan, a relatively large dome on said casing providing a relatively large space above the fuel, an air inlet to said casing, said inlet delivering air through said fuel into the casing, the space in the dome serving to permit liquid gasoline in suspension in the air to be precipitated out of the air and fall back into the casing, substantially as set forth.

In witness whereof, I have hereunto set my hand at Washington, District of Columbia, this twenty-eighth day of. May, A. D. nineteen hundred and thirty.

ARTHUR R. BAKER.