US2670725A

US2670725A - Fuel supply apparatus for internalcombustion engines

Info

Publication number: US2670725A
Application number: US168079A
Authority: US
Inventors: Clessie L Cummins
Original assignee: Cummins Engine Co Inc
Current assignee: Cummins Inc
Priority date: 1950-06-14
Filing date: 1950-06-14
Publication date: 1954-03-02
Anticipated expiration: 1971-03-02

Description

March 2, 1954 c. L. CUMMINS 67 7 FUEL SUPPLY APPARATUS FOR INTERNAL-COMBUSTION ENGINES Filed June 14, 1950 4 Sheets-Sheet 1 Ilhlllllll D Q S k INVENTOR. Ciesswfi. Gum 772mg BY 7 400 R P M. 2000 2/00 c. L. cuMMms March 2, 1954 2,670,725-

FUEL SUPPLY APPARATUS FOR INTERNAL-COMBUSTION ENGINES 4 shee tg fspget 2 Filed June 14. 1950 INVENTOR. (less-L611: QL77Z77ZZ7Z6, BY

March 2, 1954 6 c, CUMMlNs 2&7017-25 FUEL SUPPLY APPARATUS FOR INTERNAL-COMBUSTION ENGniEs Filed June 14. 1950 4sfieets'=sneet s INVENT aswl. Czz m March 2, 1954 c, cu s 2,670,725

FUEL SUPPLY APPARATUS FOR INTERNAL-COMBUSTION ENGINES Filed June 14, 1950 4- Sheets-Sheet. 4

F 6. G 96 I 97 93 3 96 a5 INVENTOR.

66 Clesszall Czmzmzzs, 60 BY Patented Mar. 2, 1954 FUEL SUPPLY APPARATUS FOR INTERNAL- COMBUSTION ENGINES Clessie L. Cummins, Palo Alto, Calif., assignor to Cummins Engine Company, Inc., Columbus, Ind., a corporation of Indiana Application June 14, 1950, Serial N 0. 168,079

17 Claims.

The invention relates generally to fuel supply apparatus for internal combustion engines and more particularly to fuel supply apparatus for multicylinder engines of the diesel type.

The general object of the invention is to provide a novel fuel supply apparatus for delivering accurately metered quantities of fuel to the respective cylinders of the. engine, the apparatus being extremely simple in construction and capable of being manufactured at a relatively low cost.

Another important object is to provide a novel fuel supply apparatus which provides for accurate control of the torque. curve of the engine under all conditions of operation.

, A further object is to provide a novel fuel supply apparatus which provides for automatic governor control of the speed of the engine, with a manually operable throttle.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, in which: I

Figure l is a diagrammatic view of a fuel supply apparatus embodying the-features of the inven tion.

Fig. 2 is a longitudinal sectional view of the apparatus shown diagrammatically in Fig. 1.

Fig. 3 is a sectional view taken on the line 33 of Fig. 2.

Figs. 4 and 5 are fragmentary sectional views illustrating valves indicated in Fig. 2.

Fig. 6 is a fragmentary Sectional view taken on the line 66 of Fig. 2.

Fig. 7 is a graph showing a torque curve that may be obtained by an engine under the control of the present fuel supply apparatus.

Fig. 8 is a diagrammatic view of a modified form of fuel supply apparatus.

In any system involving the flow of liquid through an orifice, the amount of such flow.de-. pends on three factors, namely. the size of the orifice, the pressure difference across theorifice,

and the length of the time that the orifice is open. This principle may be applied to a fuel supply apparatus for an internal combustion engine to control the flow of fuel to'the engine so that accurately metered quantities of fuel are supplied to the respective cylinders thereof. In the present instance, the fuel supply apparatus includes means for supplying fuel under a constant pressure, so that the pressure factor, of the three essential factors, becomes a constant in determining the flow. The factor of time is usually dependent: upon engine speed andthus cannot be readily varied to provide the necessary control of the operation of the engine. For example, the time factor may be dependent upon the time that two passages in a distributor are in registerwith each other or the'time that a port in a fuel injector is open. Since the distributor is driven by the engine and the opening of the port in the fuel injector is controlled by cam means embodied in the engine, the period of time that fuel is admitted to the engine is thus directly related to the speed of the engine.

The remaining factor is the size of the orifice, and the orifice in this instance may be in the form of a valve or similar controllable opening where the extent or area of opening may be directly responsive to the operation of an engine-driven governor, as well as to manual control means. In fact, in the fuel line between the source of fuel under constant pressure and the point at which fuel is ultimately delivered to the engine cylinder, there may be several orifices in series, each of which may be suitably controlled as to its effective area of opening. Where such a series of orifices is provided, the one having the smallest opening at any instant is, of course, the one that controls the flow through the system and thus becomes the fuel metering orifice. The. time factor entering into the control of the flow of fuel is not necessarily determined by the orifice which has the smallest opening at any instant, since the period of flow through such opening may be controlled at any point in the fuel line.

The present fuel apparatus may include, as a Y means to conduct fuel to the engine, either a distributor by which fiow to the respective cylinders is determined or may omit the distributor and have the fuel injectors for the respective cylinders connected to a common rail which in turn is connected to the fuel supply line or conduit. In the case where a distributor is utilized, the period of overlap between a supply passage in the distributor and each of the passages leading to the respective cylinders determines the time factor. In the case where the distributor is eliminated, each of the fuel injectors is provided with a camoperated plunger which opens and closes a supply port in the injector in timed relation to the operation of the engine and thus determines the time of opening.

In a fuel supply apparatus of the character herein contemplated where the fuel is maintained under constant pressure, a constant area of opening for the metering orifice would result in a greater fuel delivery to the engine as its speed decreases. This fact becomes evident in considering a distributor since the time during which the supply passage and each of the passages leading to the cylinders are overlapping increases with a decrease in engine speed. Similarly, the time that the supply port in an injector is opened by the plunger is increased as the speed of the engine decreases. As a result, when the engine speed i pulled down by an increased load for a given throttle setting, the torque curve of the engine would rise because of the increased supply of fuel. At full throttle, the engine torque curve would rise above acceptable limits under such conditions, thus overloading the engine.

The present invention overcomes this difficulty by providing a variable orifice in the series between a source of fuel under constant pressure and the distributor or the fuel injectors, as the case may be, with the efiective area of the variable orifice regulated by a governor to so control the fuel flow to the engine that any desired torque at maximum throttle opening may be obtained throughout the speed range of the engine. Such variable orifice is preferably provided by a needle valve operable by the governor and is used connection with another variable orifice provided by a second needle valve, also under the control of the governor but acting oppositely to the firstmentioned valve and operable to determine the maximum speed of the engine. In series with these two valves is a manually operable throttle, which may also have the form of a needle valve. The apparatus is also so arranged that an idling speed control is provided, which is connected to the governor for automatic operation.

. While the invention is illustrated in an embodiment in which the fuel is maintained under substantially constant pressure throughout the speed range of the engine, the invention contemplates the employment of a fuel pressure which may be varied with the engine speed but is constant for any given speed, and in that case the shape of first-mentioned needle valve is varied to compensate for such variation in pressure. The term constant pressure as used in the claims is therefore in the broader sense and is'not limited to the idea of a constant speed throughout the speed range of the engine.

One embodiment of the invention, shown diagrammatically in Fig. 1 and structurally in Figs.

2 to 6, is of such form that it may be mounted on one side of the engine and may comprise a main casing or housing 29 (see Fig. 2), a pump casing 21 mounted on one side of the housing 23, and a governor casing 22 mounted on the other side of the housing 20. Fuel for the engine is adapted to be drawn from a fuel supply tank (not shown) 7 through piping adapted to be connected to a fitting 28 carried by the pump casing and leading to the intake passage 23 of a pump 24 which may be of the gear type or other suitable form. The gear pump 24 discharges fuel into a passage 25 adapted to drain into a float tank 26. The float tank 26 is provided with a float-controlled valve 2'! to shut off the flow of fuel supplied by the pump 24 when the fuel in the heat chamber reaches a predetermined level. When the valve 27 closes the discharge passage 25, a relief passage 30 controlled by a pressure relief valve 31 permits the fuel delivered by the pump 24 to be returned to the intake side thereof.

The source of fuel under constant pressure in the present instance comprises a second pump 32 herein illustrated as a gear pump having a passage 33 for returning fuel, in excess of that used by the engine, to the intake side of the pump 32 with a pressure regulator 34 mounted in the passage 33. The pressure regulator 34 is of the type which maintains the pressure of the fuel at the delivery side of the pump 32 at a constant value so that there will be no variations in pressure to affect the flow of fuel through the remainder of the apparatus.

From the pump-32, fuelfl'ows through conduit means, provided by passages formed chiefly in the main housing 20, to the distributor connected to the respective engine cylinders, and the flow is controlled. by valve means mounted in such passages. The distributor is indicated generally at 35 and a main conduit or passage 36 extends from the second gear pump 32 and is connected to the distributor 35 through a series of valves. Thus, the main conduit 33 has a manually operable valve in the form of a needle valve 31 which constitutes the hand throttle for the engine. Beyond the hand throttle 31, the main passage is extended, as at 40, to open into a valve chamber 39. In the latter is a governor-controlled valve 4!, also in the form of a needle valve, 00-

operating with the opening of the passage 46 into the chamber 39 to provide a variable orifice. From the needle valve M the main passage is still further extended, as at 42, to open into a valvechamber 47 having a third. needle valve 43 mounted therein, which is also governor-conrolled. The needle valve 43 cooperates with the opening of the passage 42 into the chamber 41 to provide another variable orifice. From the latter, the main passage continues, as at 44, to the distributor 35 with a shut-on valve 45 placed in the continuation 44.

As mentioned above, both the valve 4| and the valve 43 are under the control of the governor, which is here indicated at 4B. The governor 46 is illustrated as comprising a pair of centrifugal weights 5!) pivotally carried by a rotating head 5| (see Fig. 2) mounted on and driven by a main drive shaft 52. The drive shaft 52 is journaled, as at 53, in the governor casing 22 and at its left-hand end, as illustrated in Fig. 2, extends beyond the governor casing and is there'provided with means (not shown) adapted to be connected to and driven by theengine. The other end of the drive shaft 52 is journaled in a bearing 54 mounted in the main housing 20'.

The governor weights are provided with inwardly turned fingers 55. adapted to engage a collar 56 mounted on the drive shaft 52' intermediate its ends. The governor weights 50 are so positioned, as will be observed in Fig. 2, that as the speed of the engine increases and the weights tend to move outward, the collar 56 will be moved toward the left. Resisting such movement of the collar is a spring means, indicated generally at 57, and interposed between the collar 56 and the driving head 5]; The collar 56 includesa sleeve 60 on which are provided a pair of spaced flanges!" and B2. Mounted above the flanges 6i and 62in the governor casing 22 and extending transversely to the drive shaft52 is a rock shaft 63, journaled at its ends in the governor casing 22. Secured on the rock shaft 63, intermediate its ends, is a rock lever or yoke 64 having a pair of spaced arms '65 embracing the drive shaft 5! and having rollers 56 mounted on their ends and engaging in the groove formed by the flanges 6i and 62. Thus, as the governor weights 50 move inwardly or outwardly in response to variations in the speed of the engine,

the rock shaft 63 be actuated in opposite directions, depending upon the changes in engine speed. I

Secured to the rock shaft 63, adjacent the ends thereof and on opposite sides of the main drive shaft 52, are a pair of levers T and I the lever extending upwardly and engaging the end of the needle valve 43, while the lever 1| extends downwardly from the rock shaft and engages the end of the needle valve4l. Thus, the levers 10 and H, as they are rocked by the rock shaft 63, will move the

needle valves

43 and 4| toward their closed positions, depending upon the direction of rotation of the rock shaft. To move the

needle valves

43 and 4| in an opening direction, springs 12 are mounted about the adjacent ends of the needle valves and bear at one end against the main housing 20 and at their other ends against collars 73 provided on the ends of the valves.

It will be evident from the foregoing, and by an inspection of Figs. 1 and 2, that when the speed of the engine increases and the governor weights 50 move outwardly, the rocker arm 10 will move the needle valve 43 toward its closed position against the resistance of its spring 12, while the rocker arm 7| will move in a direction permitting the spring 12 on the needle valve 4| to move the latter toward an open position. Thus, the two needle valves 4| and 43 are moved oppositely in response to changes in engine speed. Since the needle valve 43 is moved toward a closed position as the engine speed increases, such valve is utilized to determine the maximum speed of the engine. Thus, the needle valve 43 will close sufliciently to decrease the flow of fuel to the engine through the main conduit when the engine speed closely approaches its maximum and will eventually completely close the main conduit to prevent all flow of fuel to the engine and thus limit its speed. It is obvious, of course, that as soon as the speed falls below its maximum, the needle valve 43 will open to again permit flow through the main conduit.

The distributor 35 in the present instance comprises a fixed disc 14 (see Fig. 2) mounted on top of and secured to the main housing 20. Within the main housing immediately below the stationary disc 14 is a rotatable disc 15 having a drive coupling 16 with a distributor shaft 11 rotatably journaled in a bearing 80 in the housing 20. The distributor shaft 11 carries a bevel gear 8| at its lower end which meshes with a bevel pinion 82 mounted on the inner end of the main drive shaft 52. In the case of a four-cycle engine, the gear ratio between the gears 8| and 82 is 2:1 so that the distributor shaft is driven at one half the speed of the main drive shaft 52, which in turn is driven at the same speed as the crankshaft of the engine. The stationary disc 14 of the distributor is provided with an inverted U-shaped passage 83 which connects at its outer end with the continuation 44 of the main conduit. The inner end of the passage 83 is located centrally of the disc 14 and registers with a U-shaped passage 84 formed in the rotating disc 15. The outer end of the passage 84 is adapted to register sequentially with a series of passages 85 in the stationary disc 14, which and each of the passages connected'to the; cylinders varies inversely with the speed of the engine since the'time of overlap increases when the engine. speed decreases. Consequently, for a given setting of the various .valvesin the system, the amount of fuel delivered to the engine would increase with a decrease in enginespeed. Thiswould obviously. cause the torque curve of the engine to rise on decreasing engine speed and if theengine were operating at full throttle, it would cause an excessive overloading of the engine. r By means of the valve 4|,such a condition-is compensated for to a predetermined extent so. that the resultant torque curve of the engine may be of a predetermined character-and pref-- erably is substantially a fiat curve with only a slight increase in torque as theengine-speed decreases. While the valve 4| may be so construct; ed as to give any. desiredshapeto. such curve, the foregoing shape is preferred, although in some instances it may be more desirable to cause the torque to fall off at lower engine speeds. In the present construction, the needle valve 4| moves toward its closed position as the engine speed decreases. Consequently, the flow of fuel through the main conduit may thereby be decreased, upon decrease in engine speed, to compensate for the tendency toward increased flow due to the longer periodof opening inthe distributor. The extentv of'compensation thereby, obtained may be predeterminedby so shaping the valve 4| as to provide a given area of flow. about the needle valve for any given engine speed.

' The valve 4| may also b shaped to compensate.

for variations in pressureof the fuel.

The hand throttle valve 31 may be opened to any desired extent. to controlthe speed of the engine, but when fully opened to its full throttle position, the valves 4|. and 43, will exercise the necessary control over the flow of fuel. Thus, with the hand throttle 3'! fully opened, if the load on the engine is light andthe speed thereof tends to exceed the desired maximum, the governor 46 in response to such speed will shift the needle valve 43 toward its closed positionto decreases the fiow of fuel and ultimately to stop the flow of fuel so that the speed of the engine cannot exceed a desired maximum. However, if

the load on the engine increases, when the hand throttle 31 is fully opened, the engine speedwill, tend to decrease, but any tendency for increased flow of fuel due to the increased time of overlap of the ports in the distributor will be compensated for by the needle valve 4|, which decreases the flow of fuel with a decrease in engine speed.

With the foregoing arrangement, a torque curve such as illustrated by the solid lines in Fig. '7 may be attained. It will be noted that this torque curve between an idling speed of 400 R. P. M. and a speed of 2000 R. P..M. is substantially flat with only a slightly greater torque at the lower engine speeds. This form of the torque curve results from the control exercised by the needle valve 4| when the hand throttle 31 is fully opened. Should load conditions on the engine be such, that it tends to exceed a speed of 2000 R. P.- M., then the needle valve 43 begins .to close its associated orifice and the supply of fuel to the engine is decreased and'the torque falls rapidly,

as indicated in Fig.7, until at about 2100 R. P. M. the valve 43 has completely closed its orifice and no further fuel can flow to the engine. Instead of the curve shown in full lines in this figure, the valve 4| can be sov constructed as to substantially reduce the torque at lower engine speeds, as indicated by the dotted line.

The distributor 35, asheretofore mentioned, is connected to the respective engine cylinders, and more particularly is connected to injectors, one of which is indicated at 85 in Fig. 1. The fuel is delivered to each injector through a port 8 the opening of which is controlled by a plunger 90 operated by the engine camshaft. The camshaft of the engine in this instance is so-designed that the port 81 is opened shortly before the passage 84 in the rotatabl distributor I begins to overlap one ofthe passages 85 leading to the cylinder, and the plunger does not close the port 81 until after such overlapping relationship between the passages 84 and 85- has been completed. Thus, in this instance, the time factor entering into th flow to the cylinder is dependent uponthe overlapping relation between the passages 84 and 85, rather than upon the timethat the port 81 is opened.

A check valve 88 is. preferably provided. ahead of the port 81 as close to this port as possible to prevent air compressed in the cylinder during the compression stroke of the pistonfrom being forced back in the fuel line. When the engine is operating at full throttle, such air will not accumulate in the fuel lin since the fuel being supplied to the engine under such conditions will carry any air in the line along with it and thus clear the line of such air. However, at low throttle or at idling speed, if air were permitted to be forced into the line during the compression stroke, it would accumulate therein after several strokes and it would require several cycles of operation of the engine at a higher throttle opening to get rid of such air so that the engine would not quickly respond. to opening. of the throttle and acceleration of the engine. would be delayed. The check valve 88 thus prevents entrance of air into the fuel line and thereby avoids this difficulty.

As heretofore mentioned, the. present. fuel con.- trol apparatus also. includes means for providing a governed idling speed. control for the engine. To this end, a by-pass. 9| extends from the main conduit 38 around th hand. throttle 3? to the needle valve 41 so that fuel may flow through the passage 9|, when the hand throttle 3'! is closed, to operate the engine. at idle speed. The by-pass passage 91 opensinto the bore: in which the needle valve H ismounted at a. point spaced from the tapered end of the needle valve, and a groove 92 is formed in the needle valve 4t at a point which registers with the opening of the passage 5i when the engine is operating at idle speed. Extending from the groove 92 is a diagonal passage 93 formed in the needle valve 41 and opening into the valve chamber 39 in which the needle valve 4| is located. At this time, since the engine speed is low, the needle valve s3 is in its fully opened position. Thus, sufiicient fuel may flow from the pump 32 through the by-pass. passage 9| to the groove 82 and the passage 93 in the needle valve to operate the engine. at idle speed. Should the engine speed tend to increase slightly above the desired idle speed, the needle valve 4! will be moved by the governor to the left, as shown in Figs- 1 and 2, and flow through the passage 93 in the needle valve will be decreased and. eventually cut off by the movement of the needle valve toshift' the passage 93 out of communication with the valve chamber 39. When the speed of the engine has decreased sufficiently, the needle valve M will be movedto the right to again permit flow through. the nassageaet. The

engine-will thus be-maintained at idle speed under the control of the governor 46. The shut-oil valve 45in the continuation 44 of the main conduit provides for shut-off of the engine. This valve, of course, is turned to an openposition, whenever the engine is operating at any speed.

For driving the gear pumps 24 and 32, the drive shaft thereof, indicated at I60 (see Fig. 2), extends into the main housing 28. At its inner end the shaft I00 carries a bevel gear lfll which meshes with the bevel gear 8! on the distributor shaft T1. The gear pumps are thus driven by the engine.

In Fig. 8, I have shown diagrammatically a similar fuel supply apparatus, except that in this instance, the distributor has been eliminated and the continuation 44 of the main conduit is connected to a common rail having connections with the injectors for all the cylinders. One of such injectors is indicated generally at 98 and is shown as having a port 9'! through which fuel from the common rail 95' is supplied. A check valve 99 is preferably placed in the fuel line ahead of the port 2'5 and as close thereto as possible to prevent air from being forced back into the line during the compression stroke of the piston. The port Si? is adapted to be opened and closed by a plunger 38 operated by the camshaft of the en.- gine. However, in this instance, the cams are so designed that the period of time during which the port 91 is opened by the plunger 98 determines the time in which fuel is supplied to the cylinder. Since the plunger 93 is thus operated in timed relation to the speed of the engine, the period of time during. which the port 91 is open increases with a decrease in engine speed. The needle valve it, however, in this instance, under the control of the governor, compensates for the variation in time caused by changes in engine speed, so that the same form of torque curve, as illustrated in Fig. 7, may be obtained with this structure as in the case of the structure diagrammatically illustrated in Fig. l. The plungers 93 in the respective injectors 95, in the form shown in Fig. 8, are, of course, opened and closed sequentially and the opening of two or more injectors may overlap if desired.

Iciaim:

l. A fuel supply apparatus for an internal combustion engine, comprising means for supplying fuel at substantially constant pressure, means adapted to be connected to the engine for conducting fuel thereto, a conduit connecting both of said means, and a pair of oppositely acting inter connected valves in series in said conduit for controlling the flow of fuel therethrough.

2. A fuel supply apparatus for an internal combustion engine, comprising a source of fuel at substantially constant pressure, means adapted to be connected to the engine for conducting fuel thereto, a conduit connecting said source with said means, a pair of valves in series in said conduit for controlling the flow of fuel therethrough, and a governor responsive to engine speed and oppositely connected to the respective valves.

3. A fuel supply apparatus for an internal combusticn engine, comprising a source of fuel at substantially constant pressure, means adapted to be connected to the engine for conducting fuel thereto, a conduit connecting said source with said means, an engine driven governor, a variable orifice in said conduit and connected to said governor for shutting off the flow of fuel through said conduit at the maximum speed of the ensin and a second variable orifice insaid eon duit and connected to said governorfor regulating the fiow of fuel in said conduit when the engine decreases in speed from its maximum.

4. A fuel supply apparatus for an internal combustion engine, comprising a source of fuel at substantially constantpressure, means for periodically admitting fuel to the engine and operable by the engine whereby the length of the period of admission varies inversely with the speed of the engine, a governor operable by the engine, a conduit connecting said sourcewith said means, a variable orifice in said conduit and connected to said governor for shutting oh" the flow of fuel through said conduit at the maximum speed of the engine, and a second variable orifice in said conduit and connected to said governor for decreasing the fiow of fuel in said conduit when the engine decreases in speed to compensate to a predetermined extent for the increased length of the period of admission of said means.

5. A fuel supply apparatus for a multicylinder internal combustion engine, comprising a, source of fuel at substantially constant pressure, a distributor operable by the engine for periodically admitting fuel to therespective cylinders of the engine, said distributor having a series of ports adapted to be connected to the respective cylinders and a supply port movable sequentially into register with said series of ports, the speed of the engine thereby varying the period of overlap of said supply port with the respective ports of said series, and a conduit connecting said source with said supply port and having a pair of orifices in series therein and variable in effective area in response to the speed of the engine, one of said orifices being decreased in area upon increase in engine speed to determine the maximum speed of the engine and the other orifice being decreased in area upon decrease in engine speed to compensate to a predetermined extent for an increased period of overlap of said ports due to decrease in engine speed.

6. A fuel supply apparatus for a multicylinder internal combustion engine, comprising a source of fuel at substantially constant pressure, a plurality of injectors, one for each cylinder and each having a discharge port and a plunger operable by the engine for opening and closing said port, the speed of the engine thereby controlling the length of the periods when said ports are open, a common rail connected to said'ports, and a conduit connecting said source with said rail and having a pair of orifices in series therein and variable in effective area in response to the speed of the engine, one of said orifices being decreased in area upon increase in engine speed to determine the maximum speed of the engine and the other orifice being decreased in area upon decrease in engine speed to compensate to a predetermined extent for an increase in the length of the periods when said ports are open due to decrease in engine speed.

7. A fuel supply apparatus for an internal combustion engine, comprising a source of fuel at substantially constant pressure, means adapted to be connected to the engine for conducting fuel thereto, a conduit connecting said source with said means and having three orifices in series therein, and three valve members for varying the effective areas of the respective orifices, two of said valve members being oppositely acting and interconnected and being controlled in response to engine speed and the other of said valve members being manually controlled.

8. A fuel supply apparatus for an internal combustion engine, comprising a source of fuel at substantially constant pressure, means adapted to be connected to the engine for periodically discharging fuel to the engine, said means being operable by the engine whereby the length of the periods of discharge increases with a decrease in engine speed and thereby tends to increase the quantity of fuel discharged during each period to increase the torque of the engine, a conduit connecting said source and said means, a governoroperated valve in said conduit for determining the maximum speed of the engine, and a governoroperated torque control valve in said conduit for overriding the elfect of said means in determining the torque of the engine.

9. A fuel supply apparatus for an internal combustion engine, comprising a source of fuel at substantially constant pressure, means adapted to be connected to the engine for conducting fuel thereto, a conduit connecting said source and said means, a pair of oppositely acting governorcontrolled valves and a manually operable valve in series in said conduit, said conduit having a bypass extending around said manually operable valve and cooperating with one of said governorcontrolled valves for supplying fuel to theengine when operating at idle speed. i

10. A fuel supply apparatus for an internal combustion engine, comprising a source of fuel at substantially constant pressure, mean adapted to be connected to the engine for conducting fuel thereto, a conduit connecting said source and said means, a first governor-controlled valve'in said conduit for determining the maximum speed of the engine, a second governor-controlled valve in said conduit for decreasing the flow of fuel therethrough as the engine speed decreases, and a manually operable valve in said conduit, said conduit having a by-pass around said manually operable valve connected to said second valve for supplying fuelto the engine when operating at idle speed, said second valve controlling the flow of fuel through'said by-pass to maintain the .engine at idle speed.

11. A fuel supply apparatus for an internal combustion engine, comprising a source of fuel at substantially constant pressure, means adapted to be connected to the engine for conducting fuel thereto, aconduit connecting said source and said means, a manually operable throttle valve in said conduit, and governor-controlled valve means in said conduit in series with said throttle valve for controlling the flow through said conduit when said throttle valve is open, said conduit having a by-pass around said throttle valve connected to said valve means, and said valve means including a passage adapted to connect said by-pass with said first-mentioned means when said throttle valve is closed and the engine is operating at idle speed.

12. A fuel supply apparatus for an internal combustion engine, comprising a source of fuel at substantially constant pressure, mean adapted to be connected to the engine for conducting fuel thereto, a conduit connecting said source and said means, a manually operable throttle valve in said conduit, and governor-controlled valve means in said conduit in series with said throttle valve for controlling the flow through said conduit when said throttle valve is open, said valve means including an orifice and a needle valve member for decreasing the flow of fuel in said conduit when the throttle valve is open and the load on the engine decreases the speed thereof, said conduit having a by-pass around said throttle valve and said needle valve member having a transverse passage therethrough connecting said by-pass and said first-mentioned means when the throttle valve is closed and the engine is operating at idle speed, said needle valve member being governoroperated to maintain the flow of fuel through said by-pass and passage suitable for idle speed operation.

13. In a fuel supply apparatus for an internal combustion engine, a drive shaft adapted to be connected to the engine, fuel pump means driven by said shaft, a conduit for conducting fuel from said pump means to the engine, a pair of orifices v in series in said conduit, a pair of slidable valve members extending parallel to said shaft and associated with said orifices for controlling the flow of fuel therethrough, a rock shaft extending transversely to said drive shaft, a governor mounted on said drive shaft, a lever mounted on said rock shaft and connected to said governor, and a pair of rocker arms mounted on said rock shaft and in operative engagement with the respective valve members.

14. In a fuel supply apparatus for an internal combustion engine, a drive shaft adapted to be connected to the engine, a governor mounted on said shaft, a rock shaft extending transversely to said drive shaft and having a lever connected to said governor for rocking said rock shaft in response to changes in engine speed, fuel supply means including a pair of slidable valve members extending parallel to said drive shaft and located on opposite sides of said rock shaft, and a pair of lever arms mounted on said rock shaft and extending oppositely therefrom for operatively engaging said valve members, whereby said valve members are shifted in opposite directions upon change in engine speed.

15. In a fuel supply apparatus for an internal combustion engine, a drive shaft adapted to be connected to the engine, a governor mounted on said shaft, a rock shaft extending transversely to and above said drive shaft, a yoke mounted on said rock shaft intermediate its ends and connected to said governor for rocking said rock shaft in response to changes in engine speed, fuel supply means including a pair of slidable valve members extending parallel to said drive shaft on opposite sides thereof and respectively located above and below said rock shaft, and a pair of lever arms respectively mounted on said rock shaft adjacent the ends thereof and respectively extending upwardly and downwardly therefrom for operatively engaging said valve members, whereby said valve members are shifted in opposite directions upon change in engine speed.

.16. A fuel supply .apparatus for an internal combustion engine comprising a source-of fuel at substantially constant pressure, means adapted to be connected to the engine for conducting fuel thereto, a conduit connecting said source with said means, a pair of oppositely acting governorcontrolled valves in said conduit, one of said valves being adapted. to close on increase in engine speed to determine the maximum speed of the engine, and a manually operable throttle valve in said conduit located between said source and said pair of valves, whereby said one valve will operate to prevent the engine from exceeding said maximum speed .for any opening of said throttle valve.

17. A fuel supply apparatus for an internal combustion engine, comprising a source of fuel under pressure, means for periodically admitting fuel to the engine and operable by the engine, a conduit connectingsaid source with said means and having a pair of orifices in series therein for controlling the flow of fuel therethrough, a pair of governor-operated needle valves cooperating with the respective orifices for varying the effective areas thereof, one of said valves being adapted to move toward its closed position with its associated orifice on increase in engine speed to determine the maximum speed of the engine, and the other of said valves being adapted to move toward its closed position with its associated orifice as the engine speed decreases to decrease the rate of flow of fuel in said conduit, and a check valve in said conduit adapted to be positioned adjacent said means and close .to the point of admission of fuel to the enginefor preventing air from being forced .reversely into said conduit during the compression stroke of the engine.

CLESSIE L. CUMMINS.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain June 4, 1935