US1861725A - Automatic fuel regulator - Google Patents

Description

June 1932. c, sTOKES 1,861,725

AUTOMATIC FUEL REGULATOR Filed Oct. 19, 1926 5x 1 JUNE 1:- II/IIIIIIIII/l/ IN V EN TOR.

Patented June 7, 1932 UNITED STATES PATENT OFFICE CHARLES LAWRENCE STOKES, 013 LOS ANGELES, CALIFORNIA, ASSIGNOR TO CURTIS B. CAMP, TRUSTEE, 0F GLENCOE, ILLINOIS AUTOMATIC FUEL REGULATOR Application filed October 19, 1926. Serial No. 142,761. E l S S U E My invention relates to improvements in automatic fuel regulators for governing the supply of fuel to an internal combustion engine.

The principal object of my invention is to provide a carburetor for internal combustion engines which will give the optimum proportions of fuel and air to the engine for carbureting the same in accordance with varying temperatures of the engine.

Another object of my invention, is to provide a. carburetor for an internal combustion engine so that the same may be started and operated by proper carburetion to the end that no manual choking, or priming, is necessary, the carburetion depending solely on functions of the engine itself, i. e., depending on the degree of vacuum in the engine and its temperature.

Another object of my invention is to provide a thermostatically controlled carburetor.

Another object is to provide a carburetor of cheap and efficient structure.

This application is a continuation in part of my co-pending applications, S. N. 67864, filed Nov. 9, 1925 and S. N. 106,012, filed May 1st. 1926.

Referring to the drawing in which the same numbers indicate like parts:

Fig. 1 is a vertical sectional view of a carburetor embodying my invention.

Fig. 2 is a view showing the carburetor in its relation to an internal combustion engine.

Fig. 3 is an enlarged sectional view of part of Fig. 1 at starting positions.

Fig. 4 is a transverse sectional view of part of Fig. 2 showing the thermostat and the mounting therefor.

Fig. 5 is a sectional detail of part of Fig. 4.

Fig. 6 is an alternative construction for partof Fig. 4.

F ig. 7 is an enlarged fragmentary sectional view of the discharge nozzle.

Referring to Fig. 2, an internal combustion engine 1 is shown having an exhaust pipe 2, an inlet pipe 3 and a carburetor 4 attached to the intake pipe 3, the air intake 5 of carburetor 4 being attached by a hot air pipe 6 to a stove T surroumling exhaust pipe 2. A block 5 is fastened to exhaust pipe 2 and supports a bi-metallic thermostat 9 for controlling at certain times the operation of carburetor 4 through a suitable mechanism 10. Carburetor 4 may be supplied with liquid fuel, by any well known feed system, through a pipe 11. I

Referring to Figs. 1 and 3, carburetor 4 includes an air intake 5 and a mixing chamber 12 of the usual circular cross-section, mixing chamber 12 containing a large venturi 13 and a small venturi 14, the outlet of the latter being adapted to reach the throat of large venturi 13. Liquid fuel supplied through pipe 11 passes through a valve (not shown) to a fuel reservoir 15, the liquid lever therein being controlled by a float 16 attached to the valve in a well known manner. Reservoir 15 has a cover 17 and is open to atmosphere through a vent 18.

Liquid fuel from reservoir 15 passes through a passage 19 to the lower part of a well 20 of circular cross-section, divided above the passage 19 into two parts by means of a plug 21 supporting a'pipe 22 in such fashion that liquid fuel will rise to static level interiorly of tube 22. The bottom of well 20 is closed by a plug 23 having a fuelpassage 24 therethrough and supporting therein a pipe 25 which passes through the interior of pipe 22. Passage 24 is adapted to connect with a passage 26 wherein is set a nozzle 27 concentric with a second nozzle 28, the discharge of both nozzles being substantially at the throat of small venturi 14 and slightly above the liquid level XX. A passage 29 supplies nozzle 28 with liquid fuel and air from the upper part of well 20 and nozzle 27 has a small orifice 30 therein adapted to connect passage 29 with passage 26.

Liquid fuel is supplied to the interior of tube 25 through an orifice 31 and tubes 22 and 25 fit in recesses in the metal of carburetor 4 at the upper end of well 20, well 20 being open to atmosphere through a high speed regulating valve 32 and at times through a port 44, as will presently appear.

A throttle 35 is placed in mixing chamber 12 for the purpose of controlling the main supply of liquid fuel and air to engine 1 and above the closing point of throttle 33 is placed an orifice 34 for connecting mixing chamber 12 with the interior of a casing 35 which may form an extension of the body of carburetor 4. In casing 35 a valve 36 is adapted to reciprocate, the same being reduced at one end to an orifice 37 of predetermined size, the

. other end terminating in a threaded portion being controlled by the position of valve 36 with respect to the discharge from tube 25 into casing 35. Valve 36 is provided with an annular space 42 having a tapered portion 43 which is adapted to connect the interior of well through a passage 44 with an atmosphere port 45. The outer end of valve 36 is squared to work through a guide 46 in order to maintain orifices 39 and 40 in the proper relation to the discharge from tube and valve 41 and casing is expanded at guide 46 to hold a spring 47 encircling the end of valve 36 and pressing against nut 38, there being a suitable clearance between nut 38 and the interior of casing 35. The expanded portion of casing 35 is open to atmosphere through ports 48 and the casing has a threaded orifice 49 for the insertion of a pin or set screw, or other locking means, for holding valve 36 in predetermined position when desired to make the starting apparatus inoperative.

On the outer end of casing 35 is threaded an extension 50 for guiding a rod 51 which is adapted to be ,actuated by the movement of thermostat 9, responsive to the heat of engine 1, through a cup-shaped member 52 within which a spring 53 fits closely for contacting with an enlarged head 54 on rod 51, it being noted that spring 53 extends outside of member 52 to the end that a portion of spring 53 outside shall form a flexible contact having more or less universalmovementin case of misalignment, spring 53 being stiffer than spring 47.

Thermostat 9 is fastened to block 8 which is threaded into exhaust pipe 2 and one end of block 8 is cut at an angle to receive the impact of heated exhaust gases which pass through passage 58 in block 8 and deflect the same to escape to atmosphere at times through a port 59 controlled by the move ment of a valve 60 suitably fastened to member 52 and adapted. to be actuated by the movement thereof, responsive to the movement of thermostat 9. It should he noted that clearance between valve 60 and the walls of the passage 61 is allowed for equalizing the pressure on valve 60 until the same closes port 59.

An alternative construction, as shown as Fig. 6, illustrating that member 52 slides freely on the end of valve 60, the end of valve 60 being threaded to receive a nut 62 interiorly of member 52 for holding spring 53 therein and the end of 52 is now adapted to abut on the head 54. This construction permits thermostat 9 to seat valves 60 and 36 flexibly against the resistance of springs 47 and 53, it being understood that, while rod 51- is shown as straight for straight line motion, casing 50 may be curved and rod 51 may be wire as is Well known in Bowden wire mechanisms.

The operation is as follows:

Referring particularly to Figs. 1, 2, 3, 4 and 5, if it be assumed that engine 1 is at low temperature and very cold, thermostat 9 will be contracted to leave port 59 wide open and at this time a plurality of the orifices 39 will be in registry with the discharge from tube 25 and none, or one, of the orifices 40 will be in registry with atmosphere through valve 41, the position of orifices 39 and 40 being due to spring 47 which has forced rod 51 and member 52, through the medium of spring 53 into contact with thermostat 9, it being understood that there is always contact of head 54 with spring 53.

Upon cranking engine 1 with throttle 33 closed, a high partial vacuum is developed in chamber 12 on the engine side of throttle 33 which vacuum is applied through orifices 34 and 37 for elevating liquid fuel, standing at the static level XX. in pipe 25 and from the upper part of well 20 through orifice 30. The well 20 and pipe 25 comprise a reservoir of such capacity, together with the contents of passages 24 and 26 and with liquid fuel flowing through orifice 30, that the column of liquid fuel in tube 25 will be maintained substantially solid so that under the starting conditions described. there will be a very large proportion of liquid fuel drawn through orifices 39 to the cylinders of engine 1 for priming and starting the same, it being understood that during the cranking period, the resistance of spring 47 will be suflicient to maintain valve 36 in substantially fixed position.

As soon as the very rich priming charge has been fired and the engine starts to idle, there is a decided increase in vacuum in chamber 12 due to increased piston speed, the throttle 33 remaining in the same position, and this sudden increase in vacuum causes valve 36 to move toward chamber 12 a certain distance whereby one, or more, of the orifices 39 is shrouded in casing 35, thus reducing the richness of the priming mixture to a rich mixture for operating engine 1.

Engine 1 will continue to operate and the hot exhaust gases will pass to atmosphere through exhaust pipe 2 and impinge on their way on the face of block 8, whereby a portion of the hot gases is deflected through pasfices 39, one or more of the orifices 40 are exposed to atmosphere, and thus the richness of the mixture is reduced in two ways; first, by actually cutting off the liquid supply through the shrouding of one or more orifices 39, and secondly, by reducing the suction applied to the remaining orifices by the introduction of an increasing amount of air through orifices 40.

Upon the continued operation of engine 1, the same will finally reach an optimum operating temperature whereby thermostat 9 will reach its maximum expansion and valve 36 will become seated in the end of casing 35 over orifice 34, leaving only one orifice 39 for connecting the interior of valve 36 with the discharge from pipe 26. This remaining orifice will be very small and will be used as an idling orifice at optimum engine operating temperatures and the idling mixture may then be adjusted by means of valve 41.

As a general rule, the device is so proportioned that when idling one end of the liquid column in nozzle 27, passages 26 and 24 and tube 25, will not come lower than the bottom of passage 26, the demand for liquid fuel through orifices 39 during the initial priming period, as described, being suificient only to reduce the liquid level to this extent and thereafter upon shrouding some of orifices 39, as described, the demand for liquid fuel through the remaining orifices may be more than supplied through orifice 31 whereupon the liquid level in passage 26 and nozzle 27 will gradually increase until it reaches the static level X-X at which time fuel will be supplied only through the smallest and last orifice 39.

In this manner it will be seen that a very rich priming charge is first supplied to the engine and thereafter, as soon as the priming charge is fired, the richness of the mixture is cut down and gradually reduced to normal as optimum engine operating temperatures are reached.

Now upon opening throttle 33 wide, a sudden drop in vacuum to substantially atmospheric pressure will ensue in chamber 12 to the end that substantially at mospheric pressure will prevail Within valve 36, more particularly because the capacities of orifices 40 are much greaterthan that'of orifice 37, so that the column of liquid fuel being held up, as described, in tube 25, will drop and be forced from the top of nozzle 27 above the liquid level XX and this discharge of liquid fuel into the air stream is accelerated by the sudden increase in vacuum at the throat of venturi 14 due to the sudden increase in velocity of air responsive to the sudden opening of throttle 33.

Engine 1 thereupon receives an acoeleratin g charge which will empty tube 25 and nozzle 27 and thereafter a proportion of the liquid fuel for running will be supplied through orifice 31 responsive to the suction at the throat of venturi 14.

The sudden increase in suction at the throat of venturi l talso reacts on nozzle 28 to withdraw liquid fuel standing in well 20 and thereafter, as soon as well 20 and nozzle 28 are emptied, the vacuum at the throat of venturi 14 will be applied through nozzle 28, orifice 30 and passage 29 to the interior of well 20 and through a plurality of orifices 63 to the interior of tube 22 for raising the li uid level therein and causing a flow of liquid uel through one or more of orifices 63 for supplying engine 1 under varying conditions of load and speed,- it being noted that orifices 63 are all above the liquid level XX, this being desirable in order that at starting periods there shall be no more liquid fuel supplied to well 20 than what can pass through orifice 30.

With increasing, or decreasing, engine speeds, the vacuum at the throat of venturi 14 will vary, therefore varying the height of the liquid column in tube 22 and thus varying the liquid fuel supply through orifices 63 and this variation being solely due to variations in vacuum responsive to the speed, or load, of engine 1. the same may be regulated for high speed work by means of regulating valve 32.

In addition. at starting periods. if it is desired to accelerate thermostat 9 being fully contracted, it will be noted that a sudden drop in vacuum in chamber 12 caused by sudden opening of throttle will not only cause I the liquid column in tube 25 to drop and discharge as already described but will permit a sudden recession of valve 36 for opening all of orifices 39 and this recession of valve 36 causes atmosphere to be cut off from the interior of well 20 through grooves 42, 43 and passages 14 and 45. Thus in cold weather and under similar conditions of accelerating and operating, a greater or less degree of vacuum will be automatically applied by the movement of valve 36 to the interior of well 20 for causing an increased feed through orifices 63 for high speed work when engine 1 is cold.

It will be noted that. block 8 may be cast integral withpipe 2. and contains considerable metal. thus forming a reservoir for heat whereby, onstopping'engine 1 after thermostat 9 has reached maximum expansion the orifices 29 will be gradually uncovered only in proportion to that rate (if heat loss. Thus a proportionate priming charge will be supplied to engine 1, depending on its temperature, as well as a proportionate accelerating and running mixture.

Thermostat 9 and block 8 may be shrouded by a cover (not shown) to reduce the rate of cooling.

Passage 58 is provided for giving a rather quick initial expansion to thermostat 9 and bringing block 8 rapidly up to temperature, as it is desirable that a time element be involved whereby some of orifices 39 should not supply liquid fuel for too long a period.

It will be noted that the vacuum for drawing liquid fuel up. and maintaining the same for accelerating in, tube 25 is applied through valve 36 and casing 35 comprising passages for liquid fuel and air. Also, for good construction it is found that valve 36 should not be moved more than three-eighths of an inch. this being advisable on account of the maximum desirable expansion of the bi-metallic thermostat 9 which. if exceeded. causes undue stresses in the metal thereof and causes the same to operate inaccurately.

At other positions of throttle beyond starting and accelerating. as described. for varying speeds of engine 1 the supply of liquid fuel from orifices 63 will vary according to the degree of vacuum at the throat of venturi 14. but as already stated, orifices 63 should preferably be above the level X-X so that there will be a gradual overlap and supply from orifices 31 and 63. well 20 gradually filling through orifice 30 when engine 1 is not in operation. although the carburetor is entirely operative if some of the orifices 63 are below the level X-X.

After the accelerating discharge from tube 25 takes place liquid fuel is drawn through orifice 31 and a small amount of air through orifices 40 and the idling orifice 39, valve 36 being at its innermost position due to the action of thermostat 9. also air and liquid fuel will be drawn from well 20 through orifices 63 and/or passage 44 and valve 32 and thus two separate columns of liquid fuel and air, or emulsions of fuel and air, will discharge from nozzles 27 and 28 to mix at the throat of venturi 14. This action gives good atomization and carburetion.

Carburetor 4 may be used as a non-thermq statically controlled carburetor simply by in serting a locking pin or set screw in orifice 49 whereby valve 36 will be held in its innermost position. Valve 36 is a free fit in casing 35. Should there be a leak of fuel around valve 36 through orifice 34 due to the engine vacuum. a groove 64 may be. cut in valve 36 for registering with an atmosphere port 65. when valve 36 approaches its innermost position. so that air instead of liquid fuel will be drawn into the mixing chamber 12 from around said valve.

It will be understood that valves 32 and 41 may be replaced by set orifices and also that upon opening throttle 33 wide, the reciprocation of valve 36 is governed by the difference in the strength of spring 47 and thermostat 9 and may permit one or more of the orifices 39 to register with the discharge from tube 25 so that atmospheric pressure through orifices 40 will have quicker access to the interior of tube 25 for permitting the liquid fuel therein to drop more rapidly and supply nozzle 27.

lVhen the liquid fuel in tube 25 drops for sudden acceleration it is understood that the capacity of tube 25 is suflicient for the purpose of providing an accelerating charge over and above the amount which normally leaks back through orifice 31 and, as before stated, the discharge from tube 25 is not only due to the head of liquid therein over and above the liquid XX but is also due in part to the sudden increase in vacuum at the throat of Veuturi 14 although the initial discharge is believed to be solely due to the head of liquid in tube 25.

I claim:

1. In a carburetor, a mixing chamber, a throttle controlling the outlet from the mixin g chamber. a liquid fuel reservoir, a well between the mixing chamber and reservoir divided into two parts and supplied with liquid fuel from the reservoir. a liquid feed passage supplied from the well having its ends discharging into the mixing chamber one on each side of said throttle and a second liquid feed passage supplied from the upper part of the well and discharging into the mixing chamber.

The combination with an internal combustion engine of a carburetor having a mixing chamber, a throttle controlling the outlet from the mixing chamber. a liquid fuel reservoir, a well between the mixing chamber and reservoir and supplied with liquid fuel from the reservoir. :1- liquid feed passage supplied from the well having its ends discharging into the mixing chamber one on each side of said throttle. and means responsive to engine vacuum and temperature for controlling the discharge from said passage.

3. The combination with an internal combustion engine of a carburetor having a mixing chamber, a throttle controlling the, outlet from the mixing chamber. a liquid fuel reservoir. a well between the mixing chau1- her and reservoir divided into two parts and supplied with liquid fuel from the reservoir. a liquid feed passage supplied from the wellhaving its ends discharging into the mixing chamber one on each side of said throttle. a second liquid feed passage supplied from the upper part of the well and discharging into the mixing chamber and means to suppl all to the second passage.

4. The combination with an internal co1ubustion engine of a carburetor having a mixing chamber. a throttle controlling the outlet from the mixing chamber. a liquid fuel rcsc voir, a well between the mixing chamber and reservoir divided into two parts and supplied ill with liquid fuel from the reservoir, a liquid feed passage supplied from the Well having its ends discharging into the mixing chamber one on each side of said throttle, a second liquid feed passage supplied from the upper part of the well and discharging into the mixing chamber, means to supply air to said sec- 0nd passage, and means responsive to the engine vacuum to control said air supply.

5. The combination with an internal combustion engine of a carburetor having a mixing chamber, a throttle controlling the outlet from the mixing chamber, a liquid fuel reservoir, a well between the mixing chamber and reservoir divided into two parts and supplied with liquid fuel from the reservoir, a liquid feed passage supplied from the well having its ends discharging into the mixing chamber one on each side of said throttle, a second liquid feed passage supplied from the upper part of the well and discharging into the mixing chamber, means to supply air to said second passage, and means responsive to the engine temperature for controlling said air supply.

6. The combination with an internal combusti on engine of a carburetor having a mixing chamber, a throttle controlling the outlet from the mixing chamber, a liquid fuel reservoir, a well between the mixing chamber and reservoir divided into two parts and supplied with liquid fuel from the reservoir, a liquid feed passage supplied from the well having its ends discharging into the mixing chamber one on each side of said throttle, a second liquid feed passage supplied from the upper part of the well and discharging into the mixing chamber and means responsive to engine vacuum and temperature for supplying air to the second passage.

7 The combination with an internal combustion engine of a carburetor having a mixing chamber, a throttle controlling the outlet from the mixing chamber, a liquid fuel reservoir, a well between the mixing chamber and reservoir and supplied with liquid fuel from the reservoir, a liquid feed passage supplied from the well having its ends discharging into the mixing chamber one on each side of said throttle, and means actuated by engine temperature to supply air to said passage.

8. The combination with an internal oombustion engine of a carburetor having a mixing chamber, a throttle controlling the outlet from the mixing chamber, a liquid fuel reservoir, a well between the mixing chamber and reservoir and supplied with liquid fuel from the reservoir, a liquid feed passage supplied from the well having its ends discharging into the mixing chamber one on each side of said throttle, and means actuated by engine vacuum and temperature to supply air to said passage.

Signed at Los Angeles, in the county of

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