US2453329A

US2453329A - Control apparatus for internalcombustion engines

Info

Publication number: US2453329A
Application number: US641577A
Authority: US
Inventors: Lee Leighton
Original assignee: Niles Bement Pond Co
Current assignee: Niles Bement Pond Co
Priority date: 1946-01-16
Filing date: 1946-01-16
Publication date: 1948-11-09
Anticipated expiration: 1965-11-09

Description

L. LEE II CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES Filed Jan. 1S, 1946 2 Shoots-Shut 1 IN V EN TOR.

Ow mm mm N IVE lam/72m 55 I BY AGENN- Nov. 9, 1948. L. LEEJI 2,453,329

CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES I Filed Jan. 16, 1946 2 Shootg-Shqot 2 FIG. 2

INVENTUR. 1 5/5 TU/V L 5 ZZ AGENT Nov. 9,'i94e I UNI ED STAT ES 'PAT assess: coN'raoL mm'rus roa INTERNAL aN'r orrlcs I 18 Claims.

This invention relates to apparatus for control ling the supp yoi' fuel :to an internal combustion engin ,g j Fuel supply systems for internal combustion engines may, generally speaking. be classified either'ras carburetor type systemsr. in which the fuel is mixed with the'air in the air induction sys-P. tem ot'the engine. after which the mixture is distributed through the intake manifold to the ab inders; or as distri-butorvme systems, wherein the fuel charge for the engine islbroken up by a I-ueI illustrating a combined I paratus embodying my invention.

distributor mechanism into. small charges i'orthe individual cylinders, and these charges are cons" veyed to the cylinders by suitable conduits. The present invention relates particularly .to the distributor type of fuel suppl system.

An object of the present invention is vi the provision of a novel distributor typemei: supply sys tem ior an internal combustion engine, including.

improved means for controlling the ilow oi fuel to the engine.

Another object is the proyision oinovel means. 01' simple construction for effectively controlling the; supply of fuel in a distributor type system; in response to both the rate of fuel how and the rate of air flow to the engine.

The invention, in its more specific aspects, pro-- in achamber-to estaba ion w 1 el u commumc t bet een u s pply pump 80 exceeds the discharge pressure by a predetervides a member rotatable and the distributor outlet ports in predetermined succession, said member ferential pressure. said member does Such longitudinal shifting oi not vary the silent-themsbeing at the same time shiftabie longitudinally into such position that the m diflerential pressure balances the air- (lithow to, the engine by variation in the fuel pressure applied through the distributor ports to. spring loaded injector nozzles in the engine cylinders, I g

A further feature oi the invention is the control of fuel now in a distributor type supplysystem through a member shiitable to control the by-passing offuel irom the outlet to the inlet side oi the fuel pump.

Other i'eatures of the invention will be hereinafter described and claimed. I

In the accompanying drawings:

Fig. 1 is a vie'w'in longitudinal vertical section .irom the inlet Fig. 2 is a. diagrammatic view, with parts in section, showing the apparatus 01' Fig. 1 in combination with connections for control of the same by the differential pressure of air flowing to the en ine.

Referring to the drawings, the fuel control mechanism l0 includes (as shown in Fig. 1) a housing I! which contains a pump I4 01' gener- ':'ally conventional design. The pump comprises a 5.;rotor it having the usual blades l1, and driven 'bya shatt ,II which isspllned at its end so that it mayreadily be driven through a suitable connectlon from the engine. Fuel is received by the pump throughan'lnlet connection and is discharged through an outlet 22. '.,A .hy-pass valve arrangement oi known construction is provided. comprising a valve element 24 which fits into a bore 25 in the member 26, the latter being threadedly fitted into a top portion 01' the housing i2, Openings such as indicated at 21 providecommunication between the portion or the bore 25 pump inlet '20 and the a maintains said valve 24 above the valve 24;

Normally, a spring .in-its. .uppermost position wherein it prevents passage oi. i'uel downwardly through the bore 25. If, however, the pump inlet pressure for any reason mined'amount, the iuel..,to by-pass the valve 24 opens, permitting pump rotor l6, and to flow 2ll past the valve, through chamber 29, and thence directly to the outlet 22. This arrangement is useful when two pumps are connested in series in a vfluid line. It one pump fails to operate for'some reason, the by-pass valve on that pump opens to allow the other pump tomove fuel past it. Buch by-pass arrangement is wellknown, and no novelty is claimed therefor in this application.

The end ofthe Dump rotor i6 opposite the shaft ii is drivingly connected to a piston 30, which is mounted for both rotary and translatory motion in a bearing sleeve 82 fitted wtihin anextension of the housing l2. The driving connection between the rotor I8 and piston may take any suitable form for efl'ecting rotation of said piston 'while at the same time permitting translation thereof. Said connection may, as

pump and distributor ap- -mesh ing with an internal gear the pump rotor l0, while the piston 20.

' municates, through sho comprise a pinion on the piston 00. the teeth of said internal gearvbeing of suflicient translation of the piston throughout its maximum range without disengagement of said gear 00 from said pinion 20. The piston may thus be continuously rotated with also being movable longitudinally in the sleeve 02.

Rotation of the pump rotor l0 draws fuel from a suitable tank or reservoir through a conduit 80 (Fig. 2) and opening 20 (Fig. 1) and impels said fuel through discharge opening 22 into channel '40. The latter communicates at one end with said discharge opening 22 and at its opposite end, through passage 02, with an annular chamber 44 formed in portions of the housing l2 and bearing 02 and'surrounding the lefthand portion of A suitable restriction is provided in the channel 40, such as that illustrated at 40.

The annular fuel-receiving chamber 04 comope'nings 02 provided in the bearing sleeve 32, with an annular chamber 08 in the piston 30. A longitudinal slot 00 is said piston provides communication between said chamber 40 and a plurality of circumferentially spaced ports extending through the bearing sleeve 32, two of which ports are shown at 02.. Thus, as said poston rotates, said circumferentially spaced ports are brought successively into communication with the fuel-containing chamber 08.

Each of the circumferentially spaced ports above mentioned is connected by a corresponding one of a plurality of conduits 04 to a suitable injector nozzle in a corresponding cylinder of the engine or in the fuel intake passage thereof. Communication betweeneach of said ports and a corresponding conduit 00 may conveniently be effected through an associated passage 50 in a wall of a casing 58 secured to the front end of the housing l2; each passage 58 in turn communicating with the associated conduit 04 through a restriction 60. These restrictions are removable, and by varying the relative sizes of the several restrictions, may be utilized to increase the amount of fuel flow to one or more of the cylinders relative to the amount supplied to the other cylinders.

The injector nozzles may be of any suitable o well-known spring-loaded type. One form of nozzle which may be employed is shown at 02, comprising a valve head 84 carried by a stem 00, and biased to closed position by a spring 80. When fluid under pressure is supplied to the conduit 04 this pressure is communicated to the chamber 10 within the nozzle 02, and acts upon the valve head 00 to open the latter. If the pressure in line 00 increases, the valve will open wider, compressing the spring 68 further and relieving the increased pressure. Since this type of injector nozzle is well-known, further description thereof is unnecessary. In Fig. 1, the portion 00' of the conduit 00 adjacent the nozzle 02 is shown, for convenience, on a smaller scale than the portion of said conduit adjacent the casing 00.

It will be noted that the piston notch 00 is open at its outer end so that fuel may flow continuously from piston chamber 08 into the chamber 12 within the bearing sleeve 02 at the left of said piston. The latter is thus subjected at op-- posite ends to the diflerential pressure of fluid flowing through the restriction 40.. Furthermore, by providing for flow of fuel from the chamber 40 independently of the position of the slot 00 with relation to the passages 02. objectionable pulsa- 20 driven by the rotor l0 tions of fuel pressure during rapid rotation of said piston are prevented.

The casing 00 contains a flexible diaphragm ll, which separates said easing into a pair of chambers l0 and I0. Port 00 in chamber Ills connected by a conduit 02 to one or more impact tubes 00 (Fig. 2) in the path of air flowing into the passage 20 units way to the engine manifold. Port 00 in chamber I0 is connected to a Venturi gestriction 00 in said passage, through a conduit The diaphragm 10 is connected to piston 00 by any suitable means whereby movement of the diaphragm in either direction is imparted to said piston, without interfering with continuous rotation of the piston. One such means which may be employed to advantage is illustrated in Fig. l.

wherein a recessed member 00 passes through the center of the diaphragm and is pinned or otherwise suitably secured theretou- Mounted near one end in a bearing 00 in said member 00 is a shaft 00 which throughout the greater portion of its v length extends through a bearing sleeve I00. At

the opposite end, said shaft 00 is provided with a recessed head I02 having one or more fingers engaging openings or slots in lugs on the piston 20, one of which lugs is shown at I04. so that said shaft rotates with said piston and also transmits longitudinal movement thereto in response to movement of the diaphragm 14.

The conduit 02 is shown communicating with a chamber I06 (Fig. 2), which chamber communicates through conduit I00 with the throat of the venturi 90. The conduit 02, which receives the total or dynamic pressure of the air at the venturi entrance, communicates with the chamber I06 through a passage containing a restriction H0 and also controlled by a valve H2 positioned by a bellows Ill in said chamber I00. The function of said valve H2 and bellows H0 is to reduce the total pressure diiferential produced by venturi 00 by an amount suflicient to correct for decrease in density of the air due to altitude or temperature, so that the pressure drop appearing across the restriction H0 is a measure of the mass of air flowing through the venturi per and openings 21.

unit of time. Since the pressure drop across said restriction H0 is applied to the diaphragm H lt will be apparent that said diaphragm is subject to a force which is a measure of the rate of said mass air flow.

Formed in the righthand end of the bearins sleeve 22, and in the surrounding portion of. the housing i2; is an annular chamber 0. The latter is in constant communication with the bore 20 and the pump'inlet 20 through channel Ill Said chamber H0 is also in constant communication with openings I20 extending through the righthand portion of said sleeve 32.

The righthand end of the piston 20 is cut away above the gear 30 so that when said piston is in the position shown in Fig. 1, some of the fuel emerging from the pump discharge outlet 22 will scribed, the diflerential pressure corresponding to the mass air flow to the engine per unit of time urges the diaphragm l4 and piston ll to the rightz-while the fuel pressure differential across the restriction, which is a measure of the rate of fuel flow to the engine. acts upon said piston to urge the latter to the left. Under normal conditions of operation, the piston will be in the position shown .in Fig. l, with communication established between outlet 22 and inlet by way of passage 8; since the pump capacity at any given engine speed is normally much greater than any fuel how that would be required at that speed. If, now, the rate of air flow rises, the differential pressure in the chambers II and I8. becomes greater and shifts-the piston III to the right, reducing the back flow of fuel from outlet 22 to inlet 20. Thus the fuel flow to the chamber 12 at the left of the piston is increased, producing an increased pressure in said chamber: and this increased pressure acts upon the respective injector valves 64 during the rotation of the piston to open said valves further against the action of their springs and thereby increase the flow of fuel to the respective engine cylinders. The fuel differential pressure acting upon the piston 30 is also increased, and urges the piston to the left, so that said piston comes to rest in a position wherein the pressure exerted on the piston by said fuel pressure differential balances that of the increased air pressure differential. If, now,-

the air flow decreases, the fuel pressure differential moves the piston 30 further to the left, increasing the back flow of fuel to the pump inlet and decreasing the fuel flow through the chamber 72 and injector nozzles 82, until the piston reaches a position wherein the consequent decreased fuel-pressure differential balances the diminished air-pressure differential.

It will thus be apparent that, through the apparatus above described, there is maintained a substantially constant ratio between the fuel flow and the air flow.

It will also be seen that, through the above described apparatus, an increase of pump discharge pressure when the piston 30 is in balanced position will move said piston to the left from said position, allowing further flow of fuel back to the pump inlet and relieving said discharge pressure. Said piston continues to open wider the path of return fuel flow through openings I20, until the discharge pressure is reduced to such value that the fuel pressure differential is balanced by the air pressure differential. Thus, for a given air differential pressure the pump discharge pressure is maintained substantially constant; and this is achieved through the same elements that maintain a substantially constant ratio between the fuel and air flows, and without the necessity of a separate pump discharge pres sure relief valve,

If desired, a spring I22 may be provided for urging the diaphragm M to the right in Fig. l to insure that back flow of fuel through the relief passage H6 is restricted to any preferred extent when no air is flowing through the venturi 100 or when the air differential pressure is very small, as for low rates of air flow corresponding to idling positions of the throttle.

The pressure of spring I22 on the diaphragm H may be adjusted as desired by conventional spring-adjusting means, such as a nut I24 and screw I28.

The rotation of the piston 30 throughout the operation of the engine not only places the respective njector nozzles or the engine cylinders incommunication with the fuel chamber M in predetermined succession, but also eliminates static friction between the piston and the bearing sleeve 32. The piston is thus enabled to respond with particular to slight changes in the ferentials. I

The terms and expressions which I have em-' ployed are used as terms of description and not of limitation,- and I have no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but recosnize that. various modifications are possible within the scope of the invention claimed.

I claim: i 1. A fuel control system for an internal combustion engine, comprising a chamber having ports for the discharge of fuel to therespective cylinders of said engine, rotary means in, said chamber for placing said ports successively in communication with a fuel supply, a fuel pump having a fuel inlet anda fuel discharge outlet, a-portion of said rotary means being exposed to the pressure of fuel emerging from said outlet, restricted-passage means from said outlet to another means whereby the latter receives fuel for distribution to said cylinders and is subjected to the differential pressure of fluid flowing through said restricted passage means, said rotary means being movable longitudinally in said chamber in response'to variations in said fuel differential pressure, and other passage means controlled by longitudinal movement of said rotary means for providing a path for the flow of fuel from said pump discharge outlet to said pump inlet,

2. A fuel controlsystem'for an internal combustion engine, comprising a chamber having ports for the discharge of fuel to the respective air and fuel pressure difportion of said rotary .cylindcrs of said engine, rotary means in said communication with a fuel supply, a fuel pump having a fuel inlet and a fuel discharge outlet, a portion of said rotary means being exposed to the pressureof fuel emerging from said outlet, restricted-passage means for conducting fuel from said outlet to another portion of said rotary means whereby the latter receives fuel for distribution to said cylinders and is subjected to the differential pressure of fluid flowing through said restricted passage means, means connected to said rotary means for subjecting the latter to the differential pressure of air flowing to the engine, said rotary means being movable longitudinally in said chamber in response to variations in said airand fuel differential pressures, and other passage means controlled by longitudinal movement of said rotary means for providing a path for the flow of fuel from said pump discharge outlet to said pump inlet.

3. Fuel control apparatus for an internal combustion engine having spring-loaded fuel injector nozzles, said apparatus comprising a. control chamber having ports therein for the discharge of fuel to said nozzles, a member rotatable in said chamber for placing said ports successively in communication with a fuel supply, a fuel pump having a fuel inlet and .a fuel discharge outlet, a portion of said member being exposed 'to the pressure of fuel emerging from said outlet,

restricted passage means from said outlet to another portion of said rotary member whereby the latter receives fuel for disfor conducting fuel accuracy and precision for conducting fuel.

acsasao bustion engine having spring-loaded fuel injector nozzlesgsaid apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles, a member rotatable in said chamber for placing said ports successively in communication with a fuel supply, a fuel pump having a fuelinlet and a fuel discharge outlet, a portion of said member being exposed to the pressure of fuel emerging from said outlet, re-

stricted passage means for conducting fuel from said outlet to another portion of said rotary member whereby the latter receives fuel for distribution to said nozzles and is subjected to the differential pressure of fluid flowing through said restricted passage means, means connected to said member for subjecting the latter to the differential pressure of air flowing to the engine, said member being movable longitudinally in said chamber in response to variations in said air and fuel difierential pressure, and means controlled by longitudinal movement of said member for providing a path for the flow of fuel from said pump discharge outlet to said pump inlet. 5. Fuel control apparatus for an internal combustion engine having spring-loaded fuel injector nozzles, said apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles, a rotary and longitudinally movable piston in said chamber having a passage therein adapted to be brought into communication with said ports successively during rotation of said piston, means having a restriction therein forsupplying fuel to said passage. said pas sage in said piston being open at one end to the adjacent portion of said chamber for supplying thereto fuel at a pressure lower than the fuel pressure upstream of said restriction, the portion of said chamber adjacent the opposite end of said plston'being open to said upstream fuel pressure, and said piston passage being of sufflcient length to maintain substantially unchanged communication with said discharge ports despite longitudinal movements of said pis ton in response to variations in the differential I pressure of the flowing fuel.

6. Fuel control apparatus for an internal combustion engine having spring-loaded fuel injector nozzles, said apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles, a rotary and longitudinally movable piston in said chamber having a passage therein adapted to be brought into communication with said ports successively during rotation of said piston, means having a restriction therein for supplying fuel to said passage,

said passage in said piston being open at one end to the adjacent portion of said chamber for supplying thereto'fuel at a pressure lower than the fuel pressure upstream of said restriction,

. the portion of said chamber adjacent the opposite end of said piston being open to said upstream fuel pressure, and said piston passage being of sufficient lengthto maintain substan- 75 charge ports despite longitudinal movements of tially unchanged communication with said discharge orts despite longitudinal movements of said piston in response to variations in the differential pressure of the flowing fuel and means responsive to longitudinal movement of said piston for controlling the pressure of the fuel supplied to said discharge ports.

7. Fuel control apparatus for an internal combustion engine having spring-loaded fuel injector nozzles, said apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles, a rotary and longitudinally movable piston in said control chamber, the longitudinal movement of said piston being adapted to effect variations in fuel flow by varying the fuel pressure applied thro lh said ports, a fuel-receiving chamber surrounding said control chamber and having communicatlon with an interior chamber in said piston, said piston having a discharge slot in communication with said interior chamber and adapted to be brought into communication with the aforementioned ports successively during rotation of said piston, and means for supplying fuel to said fuelreceivln'g chamber.

8. Fuel control apparatus for an internal com-' bustion engine having spring-loaded fuel injector nozzles, said apparatus comprising. a control chamber havingports therein for the discharge of fuel to said nozzles, a rotary and longitudinally movable piston in said control chamber, the longitudinal movement of said piston being adapted to effect variations in fuel flow by varying the fuel pressure applied through said ports, a fuel-receiving chamber surrounding said control chamber and having communication with an interior chamber in said piston, said piston having a discharge slot in communication with said interior chamber and adapted to be brought into communication with the aforementioned ports successively during rotation of said piston, means having a restriction therein for supplying fuel to said fuel-receiving chamber, said piston slot being open at one end for supplying fuel to the adjacent portion .of the control chamber whereby an end of said piston is subject to fuel pressure downstream of said restriction, the portion of said control chamber adjacent the opposite end of said piston being open to fuel pressure upstream of said restriction, and said piston slot being of sufficient length to maintain substantially unchanged communication with said discharge ports despite longitudinal movements of said piston in response to variations in the differential pressure of the flowing fuel.

9. Fuel control apparatus for an internal com-- bustion engine having spring-loaded fuel injector nozzles, said apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles, a rotary and longitudinally movable piston in said chamber having a passage therein adapted to be brought into communication with said ports successively during rotation of said piston, a fuel pump having a fuel inlet and a fuel discharge outlet, means having a restriction therein for supplying fuel from said outlet to said piston passage, said passage in said piston being open at one end to the adjacent portion of said chamber for supplying fuel thereto at a pressure lower than that upstream of said restriction, the portion of said chamber adjacent the opposite end of said piston being open to said upstream fuel pressure, said piston passage being of suiilcientlength to maintain substantially unchanged communication with said disinjector nozzles, said apparatus comprising a.

control chamber having ports therein for the discharge of fuel to said nozzles a rotary and longitudinally movable piston in said chamber assasso having a passage therein adapted to be brought into communication with said ports successively during rotation of said piston, a fuel pump having a fuel inlet and a fuel discharge outlet, means having a restriction therein for supplying fuel from said outlet to said piston passage, said passage in said piston being open at one end to the adjacent portion of said chamber for supplying fuel thereto at a pressure lower than that upstream of said restriction, the portion of said chamber adjacent the opposite end of said piston being open to said upstream fuel pressure, means connected to said piston for subjecting the latter to a force corresponding to the differential pressure of air flowing to the engine. said piston passage being of suflicient length to maintain substantially unchanged communication with said discharge ports despite longitudinal movements of said piston in response to variations in differential pressure of the flowing air and fuel and means controlled by longitudinal movement of said piston for providing a path for return flow of fuel from said pump outlet to said pump inlet.

11. Fuel control apparatus for an internal combustion engine having spring-loaded fuel injector nozzles, said apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles, a rotary and iongitudinally movable piston in said control chamber. a fuel-receiving chamber surrounding said control chamber and having communication with an interior chamber in said piston, said piston having a discharge slot in communication with said interior chamber and adapted to be brought into communication with the aforementioned ports successively during rotation of said piston, a fuel pump having a fuel inlet and a fuel discharge outlet, means having a, restriction therein for conducting fuel from said outlet to said fuelreceiving chamber, said piston slot being open at one end for supplyin fuel to the adjacent portion of said control chamber whereby an end of said piston is subject to fuel pressure downstream of said restriction, the portion of said control chamber adjacent the opposite end of said piston being open to fuel pressure upstream of said restriction, and means responsive to longitudinal movement of said piston for controlling return flow of fuel from said pump outlet to said pump inlet.

12. Fuel control apparatus for an internal combustion engine havin spring-loaded fuel injector nozzles, said apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles, a rotary and longitudinally movable piston in said control chamber, a fuelreceiving chamber surrounding said control chamber and having communication with an interior chamber in said piston, said piston having a discharge slot in communication with said interior chamber and adapted to be brought into communication with the aforementioned ports successively during rotation of said piston, a fuel pump having a fuel inlet and a fuel discharge outlet, means having a restriction therein for conducting fuel from said outlet to said fuelreceiving chamber, said piston slot being open at one end for supplying fuel to the adjacent portion of said control chamber whereby an end of said piston is subject to fuel pressure downstream of said restriction, the portion of saidcontrol chamber adjacent the opposite end or saidpiston being open to fuel-pressure upstream of said restriction.

said piston slot being of sufficient length to maintain substantially unchanged communication with said discharge ports despite longitudinal.

movements of said piston in response to variations in the differential pressure of the flowing fuel, and means responsive to longitudinal movement of said piston for controlling return flow of fuel from said pump outlet to said pump inlet.

13. Fuel control apparatus for an internal combustion engine having spring-loaded fuel injector nozzles, said apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles. a rotary and iongitudinally movable piston in said control chamber, a fuel-receiving chamber surrounding said control chamber and having conununication with an interior chamber in said piston, said piston having a discharge slot in communication with said interior chamber and adapted to be brought into communication with the aforementioned ports successively during rotation of said piston, a'fuel pump having a fuel inlet and a fuel discharge outlet, means having a restriction therein for conducting fuel from said outlet to said fuelreceiving chamber, said piston slot being open at one end for supplying fuel to the adjacent portion of said control chamber whereby an end of said piston is subject to fuel pressure downstream of said restriction, the portion of said control chamber adjacent the opposite end of said piston being open to fuel pressure upstream of said restriction, means connected to said piston and subject to a differential pressure corresponding to the rate of air flow to the engine for acting upon said piston in a direction opposite to that in which the fuel differential pressure acts upon said piston, and means responsive to longitudinal movement of said piston for controlling said fuel differential pressure.

14. Fuel control apparatus for an internal combustion engine having spring-loaded fuel injector nozzles, said apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles, a rotary and longitudinally movable piston in said control chamber, a fuelreceiving chamber surrounding said control chamber and having communication with an interior chamber in said piston, said piston having a discharge slot in communication with said interior chamber and adapted to be brought into communication with the aforementioned ports successively during rotation of said piston, a fuel pump having a fuel inlet and a fuel discharge outlet, means having a restriction therein for conducting fuel from said outlet to said fuel-receiving chamber, said piston slot being open at one end for supplying fuel to the adjacent portion of said control chamber whereby an end of said piston is subject to fuel pressure downstream oi said restriction, the portion of said control chamber adjacent the opposite end of said piston being open to fuel pressure upstream of said restriction, means connected to said piston and subject to a differential pressure corresponding to the rate of air flow to the engine for acting upon said piston in a direction opposite to that in which the fuel differential pressure acts upon controlling the return tor nozzles, said apparatus comprising a control chamber having ports therein for the discharge of fuel to said nozzles, a, rotary and longitudinally movable piston in said chamber having a. passage therein adapted to be brought into communication with said ports successively during rotation of said piston, means having a restriction therein for supplying fuel to said passage. said passaz in said piston being open at one end to the ad- Jaoent portion oi'said chamber for supply there to fuel at a pressure lower than the fuel pressure upstream of said restriction, the portion oi said chamber adjacent the opposite end of said piston being open to said upstream fuel pressure.

means connected to said piston and subject to a diflerentialpressure corresponding to the rate Number 20 11.5mm:

l2 engine for uptins upon o x i-516w to as said p ton-inf direction ppposite-.-t .o that m which the fueldiflerlential pressure acts upon said piston, said piston poss ss helm: of suiilcient len'sth to maintain substantially unchanged communication with saiddisdhatge ports despite longitudinal rno'vement'soi said piston, and means responsive to londltudinal movement of said piston pursuant tofchlan'ge in said air or fuel diilerential: pressure fora varying the pressure or the fuel supplied to said discharge ports.

' ,L'EIGHTON LEE, II.

I arm-cannons crran The following references are of record in the file-oi this patent:

Um'ransums-mum Name Date ,Hiusser et a1. Aug. 31, 193B