US1933395A - Carburetor - Google Patents

Description

Oct. 31, 1933. H y SKOOGH 1,933,395 Y CARBURETOR Filed Nov. 30, 1951 3 Shets-Sheet l @et 3l, 1933. H. L I SKOOGH L93395 CARBURETOR Filed NOV. 50, 1931 3 Sheets-Sheet 2 H. L. SKOOGH CARBURETOR Filed NQv. 30, 1931 3 Sheets-Sheet 3 @y 2 ZM@ MM2/f@ A rofevx/Ka Patented Oct. 31, 1933 CABBURETOB Harry L. Skoogh, Jamestown, N. Y., assig'nor to Bendix Aviation Corporation,

South Bend,

Ind., a corporation of Delaware Application November 30, 1931 Selial'NO. 577,900

l15 claims. (Ci. 261-34) This invention relates to improvements in carburetors of the kind used to produce a gaseous mixture of liquid fuel'and air for the operation of internal combustion engines.

Specific objects of the invention are to provide an eflicient carburetor which is of inexpensive and practical construction and with which an appreciable economy in the use of fuel may be effected; one with which increasedgeciency may be had when the same is used in connection with internal combustion enginesV having frequentLv varying loads and which are at greatly different speeds, such'as automobile engines;- Which automatically supplies a lean mixture to the engine when the same is running under comparatively light load and at medium and high speeds; with which a rich mixture may be automatically provided to meet the demands of the engine under varying operating or road conditions occurring in the use of an automobile; and with which the fuel supply to the mixing chamber may be automatically reduced to lean the mixture when the engine is running at high speed; and with which said reducing action may be prevented at will to maintain a rich mixture during the starting and acceleration periods and running of the engine in cold weather.

Various other objects and advantages will be apparent from the following description of two different embodiments of the invention and the novel features of which will be particularly pointed out in connection with the appended claims.

Fig. 1 is a side elevation of a carburetor illustrat-ing one practicalembodiment `of my invention, and in which the various parts are in the position which they assume ywhen the engine is idling.

Fig. 2 is a fragmentary vertical section thereof, on an enlarged scale, taken on the line 2-2 of Fig. 8, showing the parts in the same position as in Fig. 1.

Fig. 3 is a fragmentary side elevation thereof, with certain parts thereof in the position occupied during the accelerating period of the motor.

Fig. 4 is a fragmentary vertical section similar v to Figure 2, but showing the pump device and automatic needle valve in accelerating position.

,Figs 5 and 6 are Views similar to Figs. 3 and 4, respectively, showing the same parts in the positions which they assume after an accelerating period of the motor has taken place and the flow of fuel reduced for high speed operations of the engine.

Fig. 7 is a side elevation thereof, partly in section, showing the position which the parts assume when the air supply to the carburetor is partly choked.

Fig. 8 is a plan view o f the carburetor.

Fig. 9 is a vertical longitudinal section there? of, on line 9 9, Fig. 8.

Fig. 10 is a side elevation, partly in section, o a carburetor illustrating another embodiment of my invention.

Fig. 11 is a fragmentary side elevation thereof, partly in section, showing the position of the parts when the flow of fuel through the pump device thereof is being retarded.

Fig. 12 is atransverse vertical section thereof, on line 12-12, Fig. 15. Fig. 13 is a side elevation of the needle valve for controlling the admission of fuel through the pump device of the carburetor shown in Fig. 11.

Fig. 14 is a horizontal section of the needle valve on line 14-14, Fig. 13.

Fig. 15 is a horizontal section of the carburetor shown in Fig. 10, taken approximately on the line 15-15 of that gure. Y

Fig. 16 is a side elevation thereof, partly in section, with the parts in the` position which they assume when the air supply to the carburetor being choked.

Fig. 17 is a similar view showing the throtvand also under certain other operative conditions of the engine. y

Fig. 19 is a similar view with thel parts in another position.

In order to illustrate this invention, two different embodiments thereof have been shown in the drawings in connection with a carburetor of the float controlled type. g

In general, the carburetor shown includes a fuel reservoir or chamber 20 receiving its supply of liquid fuel, such as gasoline, through an inlet 20a. The level of `the fuel is maintained in said reservoir by a float 21 movably supported therein and controlling va valve in said inlet in a well known manner. The carburetor further includes a mixing chamber 23 having an air in, let 24 under the control of a butterfly choke valve 25, and a suction discharge passage 26 which is connected to the intake manifold 27 of an automobile or other internal combustion engine, not shown. TheVpassage-26 is controlled by a throttle valve 28.

The fuel normally passes from the reservoir 20 to the mixing chamber 23 through an orifice 29 at they bottom of the reservoir and which leads to a passage 30 connecting with a pipe or conduit 32.r This pipe terminates in the mixing chamber 23 near the base of the suction passage 26 and constitutes the main fuel nozzle of the carburetor. The carburetor may also be provided with an upright bypass passage 34 connecting with the passage 30 and which terminates at its upper end in lateral ports 35 and 36 opening into the suction passage, and one of which may be under the control of a needle valve 37.

The fuel passage 30 is preferably formed, at least in part, in a detachable horizontal tube or tting inserted into a bore 4l in the base of the carburetor and secured by means of a threaded connection with the inner end of the bore. Said inner end of the fitting is formed with a port 44 leading by way of passage 36 to the mixing chamber 23 and with whiclr a manually operable needle valve` cooperates to permit a primary manual control of the supply of fuel passing through said port to the mixing chamber. Since the fitting 40 is rotatably secured in place, the inner portion thereof is arranged in spaced relation to the bore 41 so that the fuel can enter the passage 30 through the orifice 29 regardless of the circumferential position of said orice.

lin carburetors now in use, it is customary to adjust the amount of fuel passing through the port 44 by means of the manually operable needle valve45 so that the amount of fuel normally passing through said port will, when introduced into the air in the mixing chamber 23, result in a mixture which will be as lean as it ls possible to have it without stalling the engine when the'latter is in operation. The amount of fuel introduced into the mixing chamber is then increased during acceleration and subsequent operating periods of the engine by opening the throttle valve more or less, thus creating suction to thereby draw more fuel through the port 44.

ln the present invention, however, the needle valve 45 is so adjusted that the amount of fuel passing from the reservoir 20 to the mixing chamber 23 is suiicient to produce a moderately rich mixture tending to ensure better performance of the engine during idling and low speed periods thereof.

Means are provided which are automatically operable upon actuation of the throttle valve toward open position to first introduce an additional amount of fuel into the passage 30 upon accelerating the engine, and means to automatically reduce the normal amount of fuel passing through the port 44 after the initial acceleration period, as the engine gains speed.

For this purpose, in the embodiment of the invention illustrated in Figs. 1 to 9 inclusive, there isarranged in the reservoir 20, a pump device which includes a stationary upright pipe 5l secured in the bottom of the reservoir and in communication with the passage 30 between the port 44 and the mixing chamber 23. The upper end of the pipe 5l is closed by an enlargement or shoulder 52 below which is a port 53 extending laterally through the Wall of the pipe. Surrounding said pipe 51 and normally closing said port 53 is a slidable valve member 54 having a shoulder 55 which is normally held against the stationary shoulder 52 by a compression spring 56 arranged between the lower end of the mem- Leashes ber 54 and the bottom of the reservoir. Extending about and slidably engaging the valve member 54 is a sleeve or cylinder 58 having an open lower end and a closed upper end 59 normally disposed in spaced relation to the top face of the valve member 54, as shown in Fig. 2. The said upper end 59 of the pump device has a ball and socket or swivel connection 60 with the lower end of an upright operating rod-6l which, in turn, is pivotally connected at its upper end to the outer end of an actuating lever 62. This lever is rotatably mounted at its other end upon a horizontal pivot 63 secured to the carburetor casing.

The fuel normally passing through the orifice 29 to the port 44 is delivered from the reservoir 20 through a tapered port 64 in the bottom wall of said reservoir adjacent said orifice 29. There is reciprocally arranged in the reservoir a valve device 65 including an upright needle valve or member 66, the lower end 67 of which is tapered and adapted to cooperate with said port 64 in a manner to be described. The upper end of the needle valve 66 is guided in a vertical bore 66 of a nut or the like 69 having threaded engagement with the top wall of the reservoir. The intermediate portionof the needle valve 66 is secured within a downwardly extending, cup-like plunger 76 which telescopically engages in a freely movable cylinder 72, closed at its lower end and forms with said plunger a dash pot device. Said cylinder 72 is provided with a centrally bored axial hub in which the lower end of the needle valve is guided.

In the at-rest position of the parts, as shown in Fig. 2, the pump device 50 and the valve device 65 extend substantially below the normal fuel level in the reservoir 20 so as to be immersed therein.'

There is suiicient clearance or play between the valve member 54 and cylinder 58 of the pump device, and between the plunger 70 and cylinder 72 of the valve device to permit the interior of the cylinder 54, and of the plunger 70 and cylinder 72 to be filled to the fuel level with fuel in said position of the parts. (See Fig. 2.)

The upper end of the needle valve is provided with a pair of spaced collars 75 between which the outer end of a lateral arm 76 of a cam member 77 extends. This cam member is also rotatably mounted upon the pivot 63 and is provided with a lowex` weighted end 78 and an upwardly extending cam 79, the inner curved cam face of which terminates in a stop portion 80.

rot V The shaft 8l upon which the throttle valve 28 is mounted is provided, adjacent the lever 62 and cam member 77, with a disk. 82 preferably adjustably secured thereon, and which is provided with a lateral projection or roller 83 adapted to engage the upper edge of the lever 62. The disk is further provided, opposite this roller 83, with 'a fixed stop pin 84 against which, as shown in Fig. l, the end of the cam member 77 normally engages by the gravity action of said cam member. Between the stop pin 84and the roller 83, the disk 82 is provided with a second stop pin 85.

The parts just described are so arranged that the roller 83 engages the lever 76 in the relative positions shown in Fig. l when the throttle valve is in its closed or inoperative position. This permits the pump device to occupy the position shown in Fig. 2 where it and the lever 62 are supported through the action of the coil spring 56 and the fuel within the cylinder 58 of said device. Likewise, the valve device 65 is supported in the position shown in Fig. 2, by the engagement of .sito

the pin 84 against the end 80 of the cam member '7'7 through the connection between the arm 76 and the upper end of the needle valve 66.

The operation of the carburetor described is as follows. The manually controlled valve 45, being set relatively to the port 44 to provide a moderately rich mixture, the engine may be started, and if permitted to idle, will continue to operate upon the normal iiow of fuel through said port 44 since the throttle valve will be only slightly opened.

To accelerate the motor, the throttle valve is opened wider in the usual manner and the rotation of the `shaft 81 thereof will shift the disk 82 and cause the roller 83 'to quickly depress the lever 62 with a consequent sudden downward movement of the cylinder 58 of the 'pump device 50. Since this cylinder is substantially full of fuel at this time, the reaction set up between the cylinder and the valve member 54 through the fuel in said cylinder thereby causes the valve member 54 to move downwardly with the cylinder 58 against the opposition of the spring 56. In so doing, the port 53 in the pipe 51 of the pump device is uncovered, and through the pressure exerted upon the fuel in the cylinder, this charge of fuel will be forced through the port 53 and pipe 51 into the passage 30, thereby augmenting the normal flow of fuel through the port 44 into the mixing chamber 23. A mixture rich in fuel is thus introduced into the engine for a short period suiiicient'to enable the engine to accelerate and rapidly pick up speed. v

When the throttle valve is turned to cause an acceleration of the motor as just described, the valve device 65 will be simultaneously actuated, since the rotation of the disk 82 will cause the pin 84 to move outV of' engagement with the cam member '7'7y and the weighted arm '78 thereof will swing said member about the pivot 63 as indicated in Fig. 3. Consequently, the cam member through its engagement with the needle valve will cause a downward movement of the latter, butsince the plunger '70 and cylinder '72 thereof are both filled with fuel, the dash-pot thus created prevents the needle valve from moving down as quickly as does the positively connected pump device. The tapered lower end 6'7 of 'the needle valve 66 however eventually enters the tapered port 64 in the bottom of the reservoir and partially obstructs the outlet thereof to the passage 30, thereby reducing the normal flow of fuel thereto. This action does not take place, owing to the provision of the dash pot structure', until after the pump device has been evacuated during the acceleration of the motor, and by the time that the needle valve reaches its port restricting position, the force of the lever 62 has been expended. The spring 56 can now expand and will thus force the valve member 54 upwardly within the cylinder 58 of the pump device into normal relation with the pipe 51 and close the port 53 therein.

Consequently, by the time that the engine has gained speed, the normal amount of fuel passing to the mixing chamber 23 has been considerably reduced by restricting the flow thereof through the port 64 by the needle valve 66, as described. Since automobile engines operate under these high speed conditions for a large percentage of their total running time, a very considerable economy in fuel consumption is thus effected.

It will be understood that after the needle valve 66 has moved to its fuel feed reducing position, as explained, the pump device does not After the 4stop pin 84`has moved out of engagement with the end of the cam member '77, the latter, -by reason of its weight, has slowly lowered the needle valve against the resistance of the dash pot, said member will be arrested by the engagement of its cam face 84 with the other stop pin 85 (see Fig. 5) The rotation of the disk 82 in the movements of the throttle valve will vcause said pin 85 to move the cam member in a manner to shift the needle valve slightly up and down in proportion to the throttle valve movements, so that as the latter moves, for example toward its closed position, the needle valve will move upwardly and allow slightly greater amounts of fuel to enter the port 64, and vice versa. y

Should the engine demand be increased, as when running up-hill, the movement of the throttle valve to its wide open position will cause the disk 82 to be rotated to such an extent that the stop pin 85 will engage the overhanging part of the cam '77 thereby acting to liftl the tapered en'd 67 of the needle valve 66 out of the tapered port 64. Consequently, the increased suction of the engine will enable a sufficient extra amount of fuel to be drawn into the mixing chamber to provide the necessary rich mixture for such demand of the engine.

In all of these slight movements of the parts, however, the pin 85 will retain the cam member in such position, that, should the driver remove his foot from the accelerator and permit the throttle valve to close, the end 80v of said cam member will reengage the first stop pin 84, as the disk 82 turns backwards. This movement will, of course, cause the needle valve 66 to rise suddenly, carrying with it the plunger '70, and due to the suction between the latter and the cylinder '72, the cylinder will follow with said plunger. However, fuel in the reservoir will soon leak in between these parts and permit the cylinder to return to its lower position, thus restoring the parts of the valve device to normal position in whichv the dash pot will lbe refilled for again retarding the vdescent of the needle valve'v upon the next actuation thereof.

It is usual, when starting the engine in cold weather to choke or shut otl a portion of the air entering the mixing chamber 23 through the air inlet 24 by shifting the choke `valve 25 to a more or less closed position. Thus, less air in proportion to fuel is introduced into the mixing chamber with a given adjustment of the needle valve 45, and amore than a normally rich mixture is provided until the engine warms up. This may be accomplished by the provision of a fixed varm on the stem of the choke valve and which is operable to actuate said valve by a flexible connection 91 operatively supported in abracket 92. During this period, it is desirable to modify the operation of the needle'valve 66 to prevent it from acting to restrict the flow of fuel from the reservoir 20 since such action of the valve in cold weather by causing a lean mixture to be introduced into the engine, would be likely to cause the engine to stall.

Accordingly, the arm 99, in the construction illustrated, is provided with an extension 93 having a terminal cam portion 94 which, when the choke valve 25 is moved to the position shown in Fig. 7, engages with the depending weighted portion 78 of the cam member 77 so as to prevent the latter from swinging about the pivot 63 and f actuating the needle valve 66 when the disk 82 is turned in the operation of the throttle valve 28. When the carburetor is operated under these conditions, the pump device will rst be actuated as before to augment. the normal flow of fuel through the passage 39, after which the normal amount of fuel continues to flow through said passage 39 by way of the ports 64 and 1li since the needle valve 66 is now prevented from obstructing said portA 64.

lifter the engine has warmed up, the return of the choke valve 25 to its normal open position will shift the cam 941 out of engagement with the cam member 77 and permit the same to actuate the needle valve in the usual manner.

yllt will be seen from the foregoing that while a rich mixture is provided by the carburetor for accelerating the motor and when otherwise required, a substantial economy in the use of fuel is effected by the provision of means for cutting down the normal supply of fuel to the mixing chamber during a large proportion of the time in which the engine is infoperation.

While the foregoing description discloses a practical and operative arrangement for eiecting the results described, other constructions and arrangements of parts may be used.

lior example, the pump device and the valve device may be combined in a single operative unit, as shown in the embodiment of the invention illustrated in Figs. 19 to 19.

lin this construction, all of the fuel passing through the passage 39 to the mixing chamber 241 from the reservoir 29 enters said passage through the orifice 29, and is delivered thereto through-the combined pump and valve device.

The combined'pump and valve device includes a stationary cylinder 95 disposed in the fuel reservoir and having a bottom wall provided with a. discharge outlet 96 through which the fuel is delivered to said orifice 29. The cylinder is further provided with an. inlet opening 97 near the top thereof, preferably slightly below the normal level of fuel in the reservoir.

Between said inlet 97 and outlet 96 is a reciprocable plunger 98 having an upwardly extending hollow stem 99 which is provided adjacent 'the plunger 98 with a lateral port 109 through which fuel entering the cylinder above the plunger by way of the inlet 97 may pass through the plunger into the cylinder beneath the latter.

Slidably arranged within the hollow stem 99 of the plunger is a needle valve 191 having at its lower end a tapered portion 192disposed adjacent. the port 199 of the plunger. By suitable actuation of the needle valve 191 relatively to the plunger, the port 199 may be uncovered to permit free ow of fuel therethrough, or may be partly closed to admit reduced amounts of fuel to the lower end of the cylinder, to thereby vary the mixture to the engine.

The upper ends of the plunger stem 99 land of the needle valve 191 extend out through the top of the fuel reservoir where they are operatively connected to the throttle valve so as to be actuated by movements of the latter. For this purzontal pivot 10el on the carburetor has its free lineages end arranged so as to be engagable with a shoulder 195 at the upper end of the plunger stem. Said lever 103 is provided with an arm 106 yieldingly connected by a tension spring 107 to a dog 108 fixed to the shaft 81 of the throttle valve 28 and rotatable therewith.

An independently movable cam device 119 is also arranged on the pivot 104 and is provided with an arm 111 whichengages beneath a shoulder 112 formed on a head 114 at the upper end of the needle valve 102. The lower face of the head 114 is engageable with the upper end of the plunger stem 99. The cam device 110 is also provided with a depending weighted arm.

In the normal position of the parts, that is, when the engine is at rest or is merely idling, said parts will occupy the position shown in Fig. 10 wherein the plunger 98 is held in an upper position against a stop 11iat by an expansion spring 115 disposed between the bottom of the plunger and the bottom wall of the cylinder. In this position, a pin 118 on the lever 103 engages beneath the arm 111 of the cam device 110 and maintains the latter in a position in which said arm 11 supports the needle valve 192 with its head 114 above and out of contact with the plunger stem 99 and its lower tapered end 102 uncovering the port 100 in the plunger so that substantially a full flow of fuel will be delivered through the pump device vfrom the reservoir to the mixing chamber to provide a moderately rich mixture suitable for idling.

At this time, the dog 108 is lightly pressing against the arm 106 of the lever 193 so as to maintain said lever in the position described.

Upon actuating the throttle toward its open position for starting or accelerating the engine, the dog 108 will move approximately to the position shown in Fig. 17, thus placing the spring 107 under stress and causing the lever 193 to move into engagement with the shoulder 195 of the plunger and push the latter quickly down in the cylinder against the action oi the coil spring 115. Consequently, the charge of fuel in the cylinder below the plunger will be forced quickly through the passage 30 to the mixing chamber. thus augmenting the normal flow of fuel thereto.

During the foregoing operation, the weighted cam member 110 will move by gravity about the pivot, its arm 111 remaining in engagement with the pin 118. Thus, while the lever 103 is moving' into engagement with the shoulder 105 of the plunger stem, the needle valve 191 will move downwardly relatively to the plunger until its lower tapered end 102 partly closes the port 109. The flow of the fuel through the pump device is thus reduced after the charge of fuel below the plunger has been expelled by the downward movement of the latter.

Meantime, the engine will have gained speed, and in the ensuing normal running period of the engine, a restricted flow of fuel is maintained to the mixing chamber by reason of said partial obstruction oi the port 190. y

Since during this period the throttle valve remains in a more or less open position, the

plunger 95 will be maintained in a range of in-' termediate positions as shown in Fig. 19, the spring 115 working in opposition to the spring 107, and maintaining the plunger in a balanced or more or less floating condition.

Should it be necessary to provide a richer mixture in the chamber 23, the throttle valve is opened wide, and in the resulting downward movement of the lever 103 and arm 111 of the reservoir, `a mixing chamber provided with an cam device, a projection 120 upon the member 110 will engage with a cooperating projection 121 on the dog 108 of the throttle valve after the plunger has partially descended. Since the dogl is stationary, further descent of the arm 111 will thus be prevented, while the lever 103 will continue its descent, carrying the plunger 95 downwardly relatively to the now stationary needle valve 102. This action (see Fig. 18) causes the port 100 to be fully uncovered so as to permit suction from the engine to draw a greater than normal amount of fuel into the mixing chamber throughthe pump device. When excessive ,demand on the engine ceases, the throttle valve 108 is partly closed again, thus restoring the parts of the carburetor and pump and valve device to the position shown in Fig. 19. In this position, the pump and valve device and the actuating means therefor are permitted a limited play in opposite directions since under these conditions, the projections 100 and 101 do not engage.

As in the first construction, the choke valve actuating mechanism is provided with the c am 199 which, upon actuation of the choke valve toward its closed position, is engageable with. the weighted lower end of the cam device 110 in a manner to prevent said device from lowering the valve 101 when the lever 103 is actuatedI to lower the plunger 95. Consequently, the port 100 in the pump device will remain unobstructed, permitting a free flow of fuel and a relatively rich mixturey during the acceleration period, or funtil the engine warms up.

As soon as this condition has been effected, the choke valve is restored toits normal open position, thus disengaging the cam 119 from the cam device 110 and permitting the needle valve to be automatically operated as before.

Preferably the upper end of the plunger stem 499 is slightly bevelled, and the lower end of the needle valve head 114 is formed with correspondingly bevelled or inclined faces 120 extending into different planes, so that by rotating thevalve, the lower end 102 of said valve may be adjusted relatively to the port 100, as desired to vary the relative 'amounts of fuel passing through said port in the different positions of the needle valve.

I claim as my invention:

l. In a carburetor, the combination with afuel reservoir, a mixing chamber provided with an air inlet and a discharge passage subject to the influence of suction from an internal combustion engine, and a throttle valve for controlling the discharge of the mixture through said passage, of a pump device which is operable by the movement of said throttle valve towards open position to force additional fuel to said chamber under pressure to provide a rich mixture for accelerating said engine, and mechanism operatively connected to and movable directly by movement of said throttle valve after actuation of said pump device for reducing the fuel supply to said chamber to provide a lean mixture as said engine gains speed.

2. In a carburetor the combination with a fuel air inlet, a discharge passage subject to the influence of suction from an internal combustion engine, and a passage through which fuel is admitted from said reservoir to said chamber, of means automatically)L operable to admit and force fuel to.said chamber under pressure, and means normally automatically operable to relpredetermined quantity of fuel is admitted t0 duce the supply of fuel passing through said fuel passage after the aforesaid action of said rst means has taken place, and means operable at will to prevent said automatic operation of said second means.

3. In a carburetor the combination with a fuel reservoir, a mixing chamber having an air inlet controlled by a choke valve, a discharge passage subject to the influence of suction from an internal combustion engine, and a passage through which fuel is .admitted from said reservoir to said chamberof a pump device which is automatically operable to fadmit and forcefuel to said chamber under pressure, a valve which is normally automaticallyA operable to reduce the supply of lfuel passing through said fuel passage from said reservoir after vsaid pump devicehas v so operated, and means operable upon movement of said air choke valve to choking position to prevent said automatic operation of said other valve. f

4. In a carburetor the combination with a fuel reservoir, a mixing chamber connected to an internal combustion engine so as to be under the inuence of vsuction therefrom for supplying 100 thereto a mixture of air and fuel, a throttle valve for controlling the supply of the mixture to said engine, and a passage through which a controlled said chamber, a pump device in said reservoir actuated by an initial opening movement offsaid throttle valve to augment the amount of vfuel flowing through said passage, and a valve in .said reservoir which is also operable upon such operay `tion of said throttle valve and independently of11(1v said pum'p, after said operation of said pump device has taken place, to reduce the amount of fuel flowing through said passage from saidfreservoir below the aforesaid predetermined quantity.

5. In a carburetor the combination with a fuel 115 reservoir,I a mixing chamber connected to an internal combustion engine so as to be under the influence of suction therefrom for supplying thereto a. mixture of air and fuel, a throttle valve for controlling the supply of the mixture to said engine, and a `passage through which a fuel is admitted to said chamber, of apump device in said reservoir in communication with said passage, an operative connection between'said pump device and said throttlel valve for actuating said pump device upon opening said throttle valve to foi'ce an additional amount of fuel into said passage when said engine is accelerated, a valve in said reservoir in operative relation to said passage, and operative connections between said valve and said throttle valve whereby said valve will be actuated by opening said throttle valve to reduce the amount of fuel flowing through said passage from said reservoir after said pump has been actuated. I

6. In a carburetor the combination with a fuel reservoir, a mixing chamber provided with an air inlet, a discharge passage subject to the influence of suction from an internal combustion engine) a throttle valve controlling said passage, and a 140 fuel valve for admitting the iiow of fuel from said reservoir to said mixing chamber, of a pump device, a second fuel valve, and means automatically controlled by movements of said throttle v'alve for actuating said pump device to augment the amount of fuel passing through said first fuel valve, means also automatically controlled by movements 'of said throttle valve to initiate movement of said second fuel valve when said-- pump is actuated for reducing the amount of1.50`

ditv

fuel owing through said first fuel valve, and means associated with said second fuel valve to retard the action thereof until after the aforesaid action of said pump device has taken place.

7. In a carburetor the combination with a fuel reservoir, a mixing chamber connected to an internal combustion engine so as to be under the influence of suction therefrom for supplying thereto a mixture of air and fuel, and a fuel valve through which fuel normally passes from said reservoir to said chamber in a sumcientcontrolled lquantity to provide a moderately rich mixture, of

means operable upon acceleration of said engine for augmenting the amount of fuel to said mixing chamber, and other means, the operation of which is also initiated by the acceleration of said engine and simultaneously with the actuation' of said other means for reducing the amount of fuel passing through said fuel valve to said chamber after the acceleration of said engine ceases below said controlled quantity to provide a lean mixture in said chamber.

8. ln a carburetor the combination with a fuel reservoir, a mixing chamber connected to an internal combustion engine so as to be under the influence of suction therefrom for supplying thereto a mixture of air and fuel, a throttle valve for controlling the supply of the ture to said engine, and means for providing a predeed now of fuel to said chamber, of a pump device, an operative connection between said pump device and said throttle valve for actuating said pump device upon opening said throttle valve to force an additional amount of fuel into said mixing cham ber when said engine is accelerated, a fuel valve and operative connections between said valve and said throttle valve, whereby said fuel valve will be actuated upon opening said throttle valve to reduce the amount of fuel below said predetermined amount, after said pump has been actuated.

9. ln a carburetor the combination with a fuel reservoir, a mixing chamber provided with an air inlet, a fuel discharge'passage subject to the influence of suction from an internal combustion engine and having a .throttle valve controlling said passage, of a cylinder through which fuel passes from said reservoir to said chamber, a plunger operable in said cylinder, a valve con-z trolling an orifice in said plunger for regulating the passage of fuel into said cylinder, and which normally partially closes said orice, a part operable upon movement of said throttle valve toward its open. position to actuate said plunger to force the fuel in said cylinder into said mixing chamber for acceleration of said engine, a second part operatively engaging saidplunger valve, meansy operable prior to said accelerating movement of said plunger for actuating said second part to move said valve to a position in which said orince is uncovered to permit an unrestricted now of fuel therethrough into said cylinder, and said second part being movable to shift said valve to :its par tially closed position coincident with the travel of said plunger through its accelerating movef-1 ment.

lo. ln a carburetor the combination with a fuel reservoir, a mixing chamber having an air inlet controlled by av choke valve which is normally open, a fuel discharge passage subject to the in nuence of suction from an internal combustion engine, and a throttle valve controlling said pas= sage, of a cylinder through which fuel passes from said reservoir to said mixing chamber, a plunger operable in said cylinder, a valve controlling an orince in said plunger for regulating the passage Lacasse of fuel into said cylinder, a device operableupon movement of said throttle valve toward its open position for actuating said plunger to force the fuel in said cylinder into said mixing chamber when accelerating said engine, a second device operable to normally move said plunger valve into position to partially choke said orifice and restrict the flow of fuel therethrough coincident with the travel of said plunger through its accelerating movement, and a member which, upon movement of said air choke valve towards its closed position, is movable into engagement with said second device to prevent operation thereof and thereby cause said` device to retain said plunger valve in position to uncover said orifice during the aforesaid accelerating movement of said plunger, and thereby permit unrestricted now of fuel to said mixing chamber during said accelerating period.

ll. lin a carburetor the combination with a fuel reservoir, a mixing chamber connected to an internal combustion engine so as to be under the inuence of suction therefrom for supplying thereto a mixture of air and fuel, a throttle valve for controlling the supply of the mixture to said engine, and a passage through which fuel is admitted to said chamber, a manually operable needle valve for controlling the now of fuel into said passage from said reservoir, a pump device communicating with said passage between said needle valve and said chamber and actuated by an initial opening movement of said throttle valve to introduce additional fuel into said passage, and a second fuel valve between said first fuel valve and said reservoir which is automatically operable by said opening movements of said throttle valve to choke the flow and reduce the amount of fuel admitted to said nrst fuel valve and thus to said passage and said chamber after said pump has been actuated, whereby economy in the use of fuel-is eected during the subsequent operation of the engine. f f

l2. ln a carburetor the combination with a fuel reservoir, a mixing chamber connected to an in1 ternal combustion engine so as to be under the influence of suction therefrom for supplying there to a mixture of air and fuel, a throttle valve for controlling the supply of the mixture to said engine, and a passage through which a fuel is admitted to said chamber, a pump device, an operative connection between said pump device and said throttle valve for actuating said pumpdevice upon opening said throttle valve to introduce ad ditional fuel into said passage when said engine is accelerated, a valve in operative relation to said passage, operativeconnections between said valve and said throttle valve to actuate said valve upon opening said throttle to reduce the amount of fuel in said passage, and a dash pot associated with said valve and which acts to retard the operation of said valve until said pump has been actuated.

it. ln a carburetor the combination with a fuel reservoir, a mixing chamber connected to an in1 ternal combustion engine so as to be under the influence of suction therefrom for supplying thereto a mixture of air and fuel, a throttle valve operable for controlling the passage of the mixe ture from said chamber to said engine, and a fuel valve through which fuel normally passes from said reservoir to said chamber in predetermined quantity to provide a moderately rich mixture, of means automatically actuated by mgderate accelerating movements of said throttle valve for introducing additional amounts of fuel into said chamber to provide a richerimixture, me also lil@ lll@

ist

operable upon and by said accelerating movement of said lthrottle valve for reducing the amount of fuel passing through said fuel valve to below said predetermined quantity to provide a leaner mixture to said chamber during high speed periods of said engine, and said last means being also operable upon greater accelerating movements of said throttle valve to afford a greater than normal flow of fuel through said fuel valve when desired.

14. In a carburetor the combination with a fuel reservoir, a mixing chamber connected to an internal combustion engine so as to be under the influence of suction therefrom for supplying thereto a mixture of air and fuel, a throttle valv'e for controlling the supply of the mixture to said engine, and fuel feed means for admitting a predetermined ow of fuel to said chamber to provide a moderately rich mixture, of a pump device operable upon moderate accelerating movements of said throttle valve to admit additional amountsl of fuel to said mixing chamber, a fuel valve also operable upon and by said accelerating movements of said throttle valve to reduce said predetermined V110W of fuel through said fuel feed means during high speed periods of said engine, and said fuel valve being also operable upon and by greater accelerating movements of said throttle valve to permit more than said predetermined liow of fuel to pass through said fuel feed means When desired.-

15. In a carburetor the combination with a fuel reservoir, a mixing chamber connected to an internal combustion engine so as to be under the inuence of suction therefrom for supplying thereto a mixture of air and fuel, a throttle valve for controlling the supply of the mixture to said engine, feed means for providing a predetermined flow of fuel to said chamber, means for providing an additional charge of fuel under pressure to said mixing chamber upon opening movement of said throttle, means for reducing the flow of fuel through said feed means below said predetermined amount at relatively open positions of said throttle, and said last mentioned means being also operable to enable the supply of fuel through said feed means to be increased when desired.

HARRY L. SKOOGH.

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