US2447266A

US2447266A - Fuel control device

Info

Publication number: US2447266A
Application number: US567265A
Authority: US
Inventors: Jr Guy E Beardsley
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1939-11-03
Filing date: 1944-12-08
Publication date: 1948-08-17
Anticipated expiration: 1965-08-17

Description

Aug. 17, 1948. s. E. BEARDSLEY, JR

FUEL CONTROL DEVICE Original Filed Nov. 3, 1939 INVENTOR ATTORNEY fizyEHearz/s/gJr.

Patented Aug. 17, 1948 FUEL CONTROL DEVICE Guy E. Beardsley, Jr., West Hartford, 06m, assignor, by mesne assignments, to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Original application November 9, 1939, Serial No.

302,749. Divided and this application December 8, 1944, Serial No. 567,265

25 Claims. (Cl. 123119) proved control apparatus operative to automatically proportion the amount of fuel supplied to the engine to the amount of engine intake air.

A further object of the invention is to automatically proportion the total amount of fuel distributed by an engine fuel distributor to the total amount by weight of air. taken in by the engine.

A further object resides in the provision of an improved manually controllable engine intake air and fuel supply means in which the fuel supply means is automatically operative to accurately proportion the amount of fuel supplied to the engine to the mass flow of engine intake air, that is, the mass or weight rate of flow per unit of time, supplied undersaid manual control under normal power operation and to supply sufficient fuel to'said engine to maintain engine operation when said manual control is in its engine idling position.

A still further object resides in an improved control apparatus for an engine of the fuel injection type in which the air supply to the engine is manually controlled and the quantity of fuel distributed to the engine by a fuel injection pump or similar distributor is automatically controlled in accordance with the weight rate of air being supplied to the engine.

Still another object resides in an improved fuel control apparatus for an engine of the fuel injection type in which the injection pump for distributing I separate and distinct fuel charges to the engine utilizes a fuel pressure variably controlled in accordance with the ratio of the weights of air and fuel supplied to the engine for regulating the position of the element controlling the quantity of fuel delivered to the engine by the injection pump. v

Other objects and advantages will be more particularly pointed out hereinafter'or will become apparent as the description proceeds.

In the accompanying drawing there is illustrated, by way of example, one embodiment or mechanical arrangement for the purpose of disclosingthe invention. The drawing. however, is for the purpose of illustration only and is not to be taken as limiting or restricting the scope of the invention as it will be apparent to those skilled in the art that various changes may be made in the illustrated arrangement without in any way exceeding the scope of the invention.

In the drawing there is shown a diagrammatic illustration of an engine intake air conduit provided with a manual control and one form of engine fuel supply control for proportioning the amount of fuel supplied to the engine to the mass flow of intake air through said intake conduit, certain parts of the device being shown in seetlon to better illustrate the construction thereof.

Referring to the drawing in detail, the numeral l0 generally indicates an engine intake air conduit open at one end to the atmosphere o :v connected at that end to a supercharger, not illustrated, and provided intermediate its length with a manually controllable throttle, which maybe in the form of a butterfly valve l2, 'manually operable by the movable, link I connected by means of the lever arm I6 with the valve shaft i8. At its end past the throttle ii in the direction of airflow this conduit may be connected with an engine supercharger intake, or intake manifold, 20 by some. suitable means, such as the overlapping flanges 2| and 22. 4

Near its intake endthe conduit I0 is provided with a restriction in the form of a Venturi tube v ported upon the intake end of the intake conduit it by suitable means such as the bracket 33, illustrated as formed'integrally with the open end of the intake conduit. The interior of the casing 33 is divided by the partition 36 into two

separate chambers

40 and 42 and the upper chamber is divided transversely by a movable diaphragm 64 while the lower chamber is similarly divided by a movable diaphragm 46. Both of thediaphragms, 44 and 46, are centrally connected to a movable stem 48 which passes through the parti-' tion 36 and extends at its upper end through a slide valve plunger 50 reciprocable in a closed cylinder 52 formed or secured uponthe' upper surface of the casing end 32 in substantially concentric relation therewith.

The main fuel supply is led under pressure from a fuel supply pump, through a conduit 56 and passage 56 to an annular channel 56 provided in 3 the inner wall of the cylinder 52. The reciprocable valve plunger 58 is provided with an annular groove 88 adapted to register with/the groove or channel 58 when the plunger is in a. predetermined position. The plunger 88 is provided with a plurality of apertures or channels 87. which extend fromthe space between the plunger and the closed upperend of the cylinder 52 to the space between the end 32 of the casingfiifl and the upper diaphragm 44 and these channels are connected with the groove 88 by suitable transverse ports 84. From this description it will be apparent that whenever the plunger 50 is in position so that the groove 88 registers in whole or in part with the channel 88 fuel will flow from the conduit 84 and passage 88 into the portion of the chamber 48 above the diaphragm 44 and that the plunger 88 will always have equal pressures acting on its opposite ends because of the provision of the through channels 82.

The fuel flows from the portion of the chamber 48 above the diaphragm 44 through an orifice or restriction 88 controlled by a needle valve 88 to the conduit I8 which leads to the intake of a fuel distributing device such as a fuel injection pump, enerally indicated at 12. The device 12 has not been illustrated in detail but, for the purpose of disclosing the invention, is shown as representing any one of various forms of conventional plunger-type fuel injection pumps commonly employed to inject separate and distinct charges of fuel directly into the cylinders of internal combustion engines, through conduits such as I24, in timed relation with the engine. The application of the invention, however, is not limited to any particular form of pump as the control may be applied to other forms of fuel distributing devices.

In the illustrated construction a casing 14 is secured to, or in position relative to, the pump I2 and contains an expansible chamber element which may be in the form of a sealed bellows l8 rigidly connected at one end to the casing 14 and connected at its movable end through a pivoted link I8 with the control arm 80 of the pump 12. The control arm 80 may operate to vary the amount of fuel distributed by the pump or distributor 12 in any suitable manner such as by changing the effective stroke of its piston-type plungers in a manner well known to the art. Movement of the bellows 78 in an expanding direction to increase the stroke of the pump may be resiliently resisted by a suitable compression spring 82. The interior of the bellows 18 is connected through the branch conduit 84 with the conduit Ill leading from the fuel chamber 48 to the intake of the pump I2 so that the pump is controlled in accordance with'the pressure of the fuel in the conduit 18. The pressure of the fuel in the conduit 18 is controlled in accordance with the mass airflow through the intake conduit III by the mechanism contained in the casing 34 and associated therewith in a manner which will presently appear.

The end of the fuel conduit 18 which connects with the casing 84 is connected by means of a substantially unobstructed passage 88 with the space in the chamber 48 below the diaphragm 44.

The valve 88, cooperating with the orifice 88, is an idling control valve and remains open during power operation of the engine so that the chamber 48. is connected with the fuel conduit 18 through the orifice and the passage 88. With a flow of fuel through the line." a pressure differential will be created in the chamber 48 upon the opposite sides of the diaphragm 44, the pressure above the diaphragm being somewhat higher than the pressure below the diaphragm because of the obstruction of the orifice 88 in the passage leading from the space above the diaphragm. This pressure differential tends to move the diaphragm 44 downwardly to close the valve 88.

The chamber 42 containing the diaphragm 48 is connected with the interior of the air intake l8 through the two

passages

88 and 82 disposed one upon each side of the diaphragm. The portion of the space 42 above the diaphragm 48 is connected by the passage 88 with the annular groove 28 surrounding the throat of the venturi 24 while the portion of the space 42 below the diaphragm 48 is connected by the passage 82 with the space in th intake duct I0 ahead of the venturi 24 in the direction of air flow. Since the air pressure at the throat of the venturi is less than the pressure of the air in the relatively unrestricted portion of the intake duct on the upstream side of the venturi when air is flowing through the venturi 24 and intake duct ill, a pressure differential upon opposite sides of the diaphragm 46 since the pressure in the channel 88 connected with the venturi throat will be less than the pressure in the channel 82 connected with the unrestricted portion of the intake duct on the upstream side of the venturi. This pressure differential will tend to move the diaphragm 48 upwardly in a direction to open the valve 50.

It will thus be seen that two opposing forces exist both of which act on the stem 48, one tending to move the stem to close the fuel valve 88 in response to a pressure differential on the diaphragm 44 created by and varying as a function of the flow of fuel through the orific 88, and the other tending to open the fuel valve 50 in response to a pressure differential on the diaphragm 48 created by and varying as a function of the flow of air through the venturi 24. Since the fuel flow is controlled by the location of the fuel valve 58 these two opposing forces will balance each other at a certain relationship of fuel flow to airflow. The physical laws governing the flow of liquid and the flow of gasses through fixed restrictions indicate that this relationship will remain substantially constant over a wide range of rates of flow.

Since an aperture 88 has to be provided in the partition 38 for the passage therethrough of the stem 48 it is necessary to provide some means to separate the space'40 from the space 42 while still permitting free movement of the stem 48. Such means may conveniently take the form of a flexible seal member 94 sealed at one end to the partition 38 surrounding the aperture 98 and sealed at its opposite end to the upper surface of the diaphragm 48. The unbalancing force on the diaphragm 48 caused by the area of the interior of this seal member, connected with the portion of the space 48 below the diaphragm 44, may be counterbalanced by a similar seal member 88 sealed at one end to the undersurface of the diaphragm 48 and sealed at its opposite end to the bottom wall 84 of the chamber 88 and having its interior connected through the conduit Hill with the space in the chamber 48 above the diaphragm 44, the internal area of the seal 88 being the same as the internal area of the seal 84.

With this arrangement there is an area of the diaphragm 44 subjected to an upward force and an equal area of the diaphragm 48 within the seal 84 subjected to an equal downward force which two forces exactly cancel each other since the two diaphragms are rigidly connected together by the-stem 44, Similarly there is a downward force on an area of the upper surface of the diaphragm 44 which is exactly cancelled by an upward force on the lower surface ofan equal area of the diaphragm 46 within the flexible seal 84. Thugareas of both diaphragms 44 and 4! equivalent to the areas of the

flexible seals

84 and 88 are mutually balanced so that the effect of fluid pressure on these areas does not effect the valve controlling operation of the diapbragms. In other words,'by the arrangement shown, the seals merely reduce the effective areas of diaphragms 44 and 48. the pressures in each of the spaces above and below diaphragms 44 and 48 being eflecti ve over a net diaphragm area equal to the area of the diaphragm minus the area of the seal.

Since the regulation of the fuel flow is accomplished entirely'by differential pressures it follows that the absolute values of the fuel pressure Mamas in the line 10 does not affect the metering of the fuel by valve 50. On the other hand, the pressure of the fuel in line Ill will be transmitted through line 84 to the interior of the bellows 18 wherein the pressure of the fluid tends to expand the bellaws against the force of the spring 82. Any movements of the free-end of the bellows 0ccasioned by changes in the pressure of the fuel within the bellows is transmitted through the link it to the pump regulating arm 80..

' With the engine operating in equilibrium with the fuel andi'air being properly proportioned the air differential pressure on diaphragm 46 will be balancedby the fuel differential on diaphragm 44. If now the air flow tothe engine should increase, as by opening of throttle l2, the air differential pressure across diaphragm 48 will increase thereby urging stem 48 upwardly to further open valve 50;. As more fuel isthen being passed through valve 50 into the conduit 18 .than is being withdrawn from they conduit 18 by the pump 12, there will-be a pressure rise in the conduit 18 and a consequent expansion of the bellows I8 producingan increase in the stroke of the pumps. This increasing of the pump stroke will continue until the pumps are taking away as-much fuel from the conduit 18 as is necessary to create a-pressure drop across orifice 68 and diaphragm 44 which willbalance the air pressure differential across diaphragm 48, whereupon the fuel to air ratio supplied the engine will be re-established or maintained at its desired value and the stem 48 and its diaphragm assembly will again be in equilibrium. Similarly if the flow of fuel through the metering valve .58 falls below the capacity of the pumps at a particular stroke setting, as will occur upon closing of the throttle I2 and resulting closing movement of valve 50. the pressure inconduit 70 will decrease and a readjustment of the pump stroke will be accomplished to reduce the pump capacity such. that the flow through the metering valve and metering orifice will be just sufflcient to reestablish equilibrium of the fuel and air differential pressures acting on diaphragms 44 and 46. Substantially constant fuel to air proportioning is thus obtained.

When the engine speed is very low, as when the 'engine is operating in the idling range, an enriched mixture is desired. .In addition. during .idling the mass flow of air through the air intake and venturi will be so small as to create only a very slight pressure diflerential in the chamber 42 on the opposite sides of the diaphragm 4',

which pressure difference, while theoretically effective to continue the control of the metering valve 80, is practically undependable because of frictional effects and other factors of resistance in the mechanism. Therefore, in'order to insure a steady and sufficient supply or fuel in the low speed range a suitable resilient member, such as the coil spring I82, is disposed below the diaphragm 48 to resiliently urge the valve 58 to partially open position. This spring may conveniently be disposed in the lower seal member 88 as illustrated and exerts a force which is in addition to and inthe same direction as the force created on stem 48 by the air differential pressure on diaphragm 48. An increased fuel flow is thus provided such that the force created on stem 48 by the fuel differential pressure on diaphragm 44 is ufficient to balance both the air force and the spring force. The mixture richness is thus increased at idle as is desired. The spring force is, however, comparatively slight since'the force exerted by the fuel differential tending to close the ferential force relied upon to control the fuel metering operation of .the fuel valve 50.

-It has been founddeslrable to select an idle spring I02 of a strength sufficient to provide an excessive enrichment at idle and then to decrease the enrichment by using a throttle controlled valve arranged to restrict the efl'ective area of the metering orifice 88 as the throttle approaches idling position thereby making available any de-.

sired idle and near idle enrichment. This is accomplished by the valve 88 which is, operatively connected withthe throttle valve shaft I8 by means of the link Ill and levers I20 and I22. The valve 88 and its operating elements are so constructed and arranged that the valve does not begin to restrict the orifice 88 until a low engine speed throttle setting is reached at which the effect of the spring [02 becomes important in contrplling the operation of the valve: 58. At all smaller throttle openings and hence all lower engine speeds the fuel is metered to the engine by the valve 68 operating in conjunction with the orifice 66 and the metering valve 50 and the air and fuel flow at these low speeds is controlled primarily by the position of the throttle t2 and the valve 88 rather than by the effect of mass airflow through the venturi 24 on the diaphragm 46. This method operates effectively for the low speed throttle settings indicated since at each such throttle setting the mass flow of intake air through the engine remains substantially constant and a constant fuel supply is, therefore, required. Although changes in the engine load such as are occasioned by changes in the pitch of the engine driven propeller or changes in the flying attitude of an engine carrying airplane may cause the engine speed to vary within relatively wide limits, the mass airflow to the engine remains substantially constant for these various engine speeds because of the well known physical law further decreases in the pressure of the gas in the conduitbeyond the restriction in the direction of flow from a value approximately one-half the pressure in the conduit ahead of the restriction do not-increase the rate of flow through the conduit. Thus, since with throttle settings in the engine idling range, the pressure ahead of the throttle is normally more than twice the pressure beyond the throttle, the airflow will remain substantially constant for any particular throttle setting regardlessof variations in engine speed.

It is a circumstance well known to the art that the density of atmospheric air decreases with increases in altitudes, and that the reduction in pressure at the throat of a venturi for any given mass airflow therethrough varies in inverse proportion to the square root of the air density. This indicates that the same mass airflow through the venturi will not produce the same pressure drop at the'Venturi throat if the altitude varies with a consequent variation in atmospheric air density and that it is necessary, therefore, to incorporate an altitude compensating device in any apparatus designed to function in accordance with mass airflow if the apparatus is to function correctly at different altitudes.

The following description is illustrative of one manner in which the necessary altitude compensation can be accomplished.

A restriction or orifice 90 is disposed in the channel and a channel I04 is provided interconnecting the channels 00 and 92 and having a restriction or orifice I00 therein. The opening through the orifice I06 is controlled by a needle valve I00 operated through a suitable leverage, including the links H0 and II! and the belicrank II4, by an expansible element I I6 disposed in the air intake conduit adjacent to the intake end of the venturi 24 and responsive to changes in the density of the air surrounding it. When the density of the air in the intake ahead of the venturi is at normal sea level temperature and pressure, the

eXpansi-ble element H0 is contracted until the needle valve I00 closes the aperture I00, in which case the restrictions I00 and 90 are inoperative and the diaphragm 46 is subject directly to the pressure difference between the air pressure ahead of the venturi and the pressure at the venturi throat. If the air in the intake ahead of the venturi is at a density less than that of the air at sea level the element H6 will expand and move the valve I00 to open the orifice I00 an amount proportional to the variation of the air density from the density at, sea level. With the orifice 100 thus partially open, air will flow through this orifice into the channel 00, to the orifice 90, the annular space 20. and out the openings 20 due to the pressure differential existing along this path. Because of this fiow the portion of the channel 00 between the restrictions I00 and 00 will then have a pressure different from either the pressure in the channel 92 or the pressure at the venturi throat but proportional to both. By properly contouring the needle I00 and selecting the correct sizes for the orifices I00 and 80 it can be so arranged that the pressure diflerential on opposite sides of the diaphragm 46 is maintained constant for the same mass airflow regardless of the density of the air in the air intake ahead of the venturi, since the space in the chamber 42 above the daphragm 46 is connected to the portion of the channel 00 between the restrictions I00 and 00.

While but one specific embodiment of the invention has been illustrated in the accompanying drawing and hereinabove described for the purpose of disclosing the invention, it is to be understood that the invention is not limited to the particular arrangement ,so illustrated and described, but that such changes in the size, shape and arrangement of the'various parts may be resorted to as come within the scope of the subjoined claims. A portion of the subject matter disclosed but not claimed herein is being claimed in the copending application of Frank 0. Mock Serial No. 362,572, filed October 24, 1940, a continuation of abandoned application Serial No. 118,718, filed January 2, 1937.

Having now described the invention so that others skilled in the art may clearly understand the same, what it is desired to secure by Letters Patent is as follows:

1. In a direct injection fuel system for an internal combustion engine having an'air intake, an injection pump having a pluralityof outlets for introducing a measured amount of fuel into respective engine cylinders, a fluid chamber and a fluid pressure responsive element for varying the capacity of said pump to vary the amount of fuel delivered by said pump through said outlets to said engine, a conduit connected with said chamber and with the inlet of said pump, a valve for controlling the admittance of fuel to said conduit, and means for adjusting said valve to maintain the 'rate of flow by weight of fuel delivered to said engine by said pump in predetermined ratio to the rate of flow by weight of intake air to said engine, said means including a venturi in said air intake for measuring the rate of flow by weight of air to said engine and a metering orifice for measuring the rate of flow by weight of fuel to said pump. 1

2. In an apparatus for directly injecting liquid fuel into a combustion chamber having an air intake, an injection pump having an outlet conduit associated therewith for delivering liquid fuel to said combustion chamber, adjusting mechanism including a pressure responsive member for varying the pumping capacity of said pump to control the amount of fuel pumped by said pump to said combustion chamber, a fuel inlet conduit connected with said pump and in communication with said pressure responsive member, and means including a fuel flow regulating valve in said inlet conduit upstream of said pressure responsive inember for maintaining the amount of fuel by weight per unit of time delivered to said combustion chamber by said pump in predetermined ratio to the amount of air by weight per unit of time passing to said combustion chamber through said air intake, said means also including, a fuel metering orifice in said inlet conduit for measuring the rate of flow .by weight of fuel to said pump, a venturi in said air intake for measuring the rate of flow by weight of air through said air intake, and means for actuating said fuel valve in accordance with variations in the pressure drop across both said fuel orifice and said venturi.

3. A fuel injection apparatus for an internal combustion engine having an air intake and a throttle valve, including, an injection pump having a plurality of outlets for distributing liquid fuel among respective engine cylinders, fuel pressure responsive means connected with the mechanism of said pump operative to vary the amount of fuel delivered by said pump through said outlets to said engine, and control mechanism operatively associated with said fuel pressure responsive means to maintain the rate of fiow by weight fuel pressure difference which is a measure of the' rate of flow by weight of fuel through said pump,

a valve for regulating the flow of fuel to said pump, means foroperating said valve by both said air pressure difference and said fuel pressure difference, and mechanism connected with said throttle for controlling the fuel flow through said metering means in accordance with the position of said throttle.

' 4. An apparatus for pumping and regulating the flow of liquid fuel at a pressure and for the direct injection of said fuel into an engine cylinder having an air intake, comprising, an injection pump having a relatively high pressure fuel outlet for introducing a measured amount of fuel into said engine cylinder, means for supplying fuel at a pressure lower than the injection pressure to said injection pump, a metering device interposed between said supply pump and said injection pump, said metering device including means for measuring the rate of flow of fuel by weight to said injection pump and the rate of flow of air by weight tosaidair intake and a fuel valve for controlling the rate of flow by weight of fuel from said fuel supply means to said injection pump in predetermined ratio to the rate of flow by weight of air to said air intake, adjustable means for varying the amount of fuel pumped by said injection pump to said engine cylinder, and fuel pressure actuated means for adjusting said adjustable means in response to variations in the relation between the rate of flow of fuel through said valve to said injection pump and the rate of flow of fuel from said injection pump to said cylinder. I

5. In combination, a fuel injection pump having a plurality of outlet conduits associated therewith for distributing liquid fuel among the cylinders of an internal combustion engine having an air intake, means for feeding fuel to said pump, means for varying the rate of flow of fuel fed to said pump in predetermined'relation to the rate of flow by weight of air flowing to said engine through said intake, and mechanism responsive to variations inthe relation between the rate of flow of fuel to said pump and the rate of flow of fuel from said pump for varying the capacity of said pump in accordance with said variations in the ratio of said fuel flow rates.

6. In a direct injection fuel system for an internal combustion engine having an air intake, an injection pump having a plurality of outlets for introducing a measured amount of fuel into respective engine cylinders, a conduit connected to said pump, a valve for controlling the rate of flow of fuel through said conduit, means responsive to the rate of fuel flow through said conduit and the rate of air flow through said air intake for regulating said valve, and mechanism responsive to the pressure in said conduit for increasing the capacity of said pump in accordance with increases in said pressure and for decreasing the capacity of said pumpin accordance with decreases in said pressure.

'7. In a system for supplying fuel and air to a fuel injection engine, an air passage, a venturi in said air passage creating an air differential 10 a pressure, a fuel-injection pump, a control forvarying the quantity of fuel delivered by said pump, yielding means urging the control in a direction to decrease the pump delivery, means actuated by the pressure of the fuel supplied to the pump for urging the control in a direction to increase the pump delivery, and valve means responsive to the air differential pressure for varying the pressure of the fuel supplied to the pump.

8. In a direct injection charging system for an engine having a combustion chamber and an air intake, an injection pump for delivering a measured' amount of a liquid charge into said com-'- bustion chamber, a liquid inlet conduit connected to said pump for supplying said liquid thereto, means for regulating the rate of flow of liquid through said conduit in predetermined ratio to the rate of flow of air through said air intake, and means responsive to variations in'the pressure of said liquid for varying the capacity of said pump to maintain the amount of liquid defuel charges to the individual engine cylinders, a

control for varying the quantity of fuel delivered by said pump, yielding means urging the control in a direction to decrease the pump delivery, fuelpressure actuated means for urging the control in a direction to increase the pump delivery, andmeans responsive to the air differential pressure for controlling the fuel pressure actuated means..

10. In combination with an internal combus-, tion engine, a fuel injection pump, an air passage, an element controlling the eifective pumping capacity of the pump, an element controlling the air passage, means for manually actuating one. of said elements, a movable wall connected to. the other element, and means including a fuel pump for supplying fuel to the injection pump and for supplying fuel at a-variably controlled pressure to said movable wall for actuatin the other element. '1

11. In combination with .a multi-cylinder internal combustion engine, a fuel injection pump having a plurality of pumping members, an element movable to vary the effective pumping ca-: pacity of the members for varying the fuel supply to the engine, an air supply passage, an element a for varying the air supply to the engine, a manusupply to the engine, manual means for actuat ing one of said elements, a fuel pressure respon sive movable wall for actuating the other of said elements, a fuel conduit supplying fuel to'the" injection pump, means including a fuelvalve for varying the pressure or .the fuel on said wall,-. and means responsive to air pressures at spaced.

points in the air passage and to fuel pressures at spaced points in the fuel conduit for controlling. said 'valve. v

- 13, The invention defined in claim 12 comprising in addition a sealed capsule responsive to variations in altitude for modifying the control of said valve. 7

14. In a charge forming device, a fuel injection pump, an air passage, an element controlling the effective pumping capacity of the pump, an element controlling the air passage, means for manually actuating one of said elements, a movable pressure responsive member for actuating the other element, means for subjecting the membet to fuel pressure, and means responsive to air pressures varying with the rate of air flow to the engine and to fuel pressures varying with the rate of fuel supply to the engine for varying the fuel pressure on the member to control the said other element.

15. In a charge forming device, an air passage, a differential pressure creating means in the air passage, a throttle in the passage, an element for controlling the throttle, a fuel injection pump, an element for varying the effective pumping capacity of the injection pump, a fuel suppl pump, a conduit from the supply pump to the injection pump, a differential pressure creating means in the conduit, means for manually actuating one of the elements, a movable pressure responsive wall operatively connected to the other element, means for subjecting the wall to fuel pressure, and means responsive to the pressures createdby the differential pressure creating means in the air passage and in the fuel conduit for controlling the said fuel pressure.

16. In a fuel feeding system for a direct injection engine, a fuel injection pump for inter.- mittently delivering fuel directly to the engine cylinders in timed relation therewith, a fuel conduit for supplying fuel to said pump, area restricting means in the conduit, an air conduit for supplying air to the engine, a venturi in the air conduit for creating an air differential pressure, means for modifying the air differential pressure in accordance with the temperature and pressure of the air in the air conduit, diaphragm means subjected to the modified air differential pressure and to a differential in fuel pressures resulting from flow through the area restricting means, manually operable means controlling the flow through one of the conduits, an element controlling the flow through the other conduit, a pressure responsive movable wall for actuating said element and subjected to fuel under pressure, and means connected to said diaphragm means for varying the fuel pressure on said movable wall to control said element.

17. In a fuel injection system for an engine, a fuel injection pump, a fuel conduit leading from the pump to a cylinder of the engine for supplying individual charges of liquid fuel thereto in timed relation with the engine, a fuel control element for varying the quantity of fuel in the individual charges, an air passage for supplying air to the cylinder, a control element for varying the quantity of air supplied to the cylinder, manual means for actuating one of said elements, a movable pressure responsive wall operatively connected to the other element, means including a fuel conduit for supplying fuel to the pump and to the wall, and means responsive to air and fuel pressures varying in accordance with variations in the flow of fuel and air to the engine for vary- 12 ing the pressure of the fuel on said wall for operating said other element.

18. In a fuel feeding system for a direct injection engine, an air passage for supplying air tr th engine, a venturi and a throttle in the passage, an element connected to the throttle, a fue injection pump for intermittently supplying individual fuel charges to the engine cylinders ir timed relation therewith, a movable element f0] varying the quantity of fuel in the fuel charges a fuel conduit for supplying fuel to the pump area restricting means in the conduit, a valve lr said conduit, means responsive to the pressuri in the venturi and to the pressures in the fue conduit anterior and posterior to the area restricting means for controlling said valve, manual means for actuating one of said elements ant means responsive to the fuel pressure in salt conduit posterior tothe valve for actuating thi other of said elements.

19. The invention defined in claim 18 whereir a decrease in pressure in the venturi tends t1 open said valve,

20. In a fuel feeding system, a fuel injectioi pump comprising a housing and a plurality of fue pumping units therein receiving fuel from with in the housing, a fuel conduit supplying fuel t1 the housing, means including a movable wall re sponsive to the pressure of the fuel supplied to th housing for varying the effective pumping ca pacity of said units, an air supply conduit, ant means responsive to pressures resulting fron flow through said conduits for varying the pres sure of the fuel supplied to said housing to there by actuate the said capacity varying means.

21. The invention defined in claim 20 com prising in addition means responsive to variation: in the pressure of the air entering the air condui accompanying a change in altitude for varyin the pressure of the fuel supplied to the housing.

22. A system for supplying fuel and air to at injection engine, comprising an air passage having a throttle, a venturi'in the passage anteriol to the throttle for creating an air diiferentia pressure, a fuel injection pump for intermittent]: injecting separate and distinct charges of fue into the respective combustion chambers of thl engine in timed relation therewith and having a control element for varying the quantity of fue in said charges, a conduit for supplying fuel ti the pump, area restricting means in said condui creating a fuel differential pressure, a 'pressurl responsive movable wall subjected to fuel pressure operatively connected to said control element, and means responsive to said air and fue diflerential pressures for varying the fuel pressure on said wall to actuate said control element 23. The invention defined in claim 22 comprising in addition means for varying the effectivl area of the area restricting means.

24. In combination with an engine having ar air-intake conduit provided with a throttle anc fuel supply means having an outputproportiona to engine speed and whose output at any giver speed is variable, a member movable to controi the output of said fuel supply means, automatil fuel-air ratio controlling mechanism functioning 13 air-intake conduit provided with a throttle, a fuel supply means having an output proportional to engine speed and whose output at any given speed is variable, a member movable to control the output of the fuel supply means, automatic fuel-air ratio control mechanism functioning to meter fuel to said fuel supply means at a predetermined fuel-air ratio for each operating position of the throttle and to vary the pressure of the metered fuel upon variation in said fuel-air ratio, and a movable pressure-responsive element operatively connected to said member and subjected directly to metered fuel pressure for regulating the effective delivery of the'fuel supply means in response to variations in the 15 2,297,

metered fuel pressure.

I GUY E. BEARDSLEY, JR. 7

, 14 anrnmmcns crrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,004,869 Hogg June 11, 1935 2,139,891 Sugihara Dec. 13, 1938 2,142,086 Alden Jan. 3, 1939 2,150,075 Mennesson Mar. 7, 1939 2,217,364 Halford et al. Oct. 8, 1940 2,269,294 Udale Jan. 6, 1942 2,281,411 Campbell Apr. 28, 1942 Gosslauet al Sept. 29, 1942 Certificate of Correction Patent No. 2,447,266.

GUY E. BEARDSLEY, JR.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 25, after 'difl'erential insert the words will be created; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 30th day of November, A. D. 1948.

[SEAL] THOMAS F. MURPHY,

Assistant Oommz'ssz'oner of Patents.

August 17, 1948.