US2943847A - Fuel injection flow control valve - Google Patents

Description

Filed April 3, 1958 FUR $917K a W, WM m w mm M a o Z w w r WA... 2 A 7 a W i w V y m w w i../.../ fl M 9 Wu Z v W WM 2 w v w w If.

ATTORNEY V 2,9L43,s47- 1; monoNrLowjoonTRoL vALvE no'nina C. Scoville, Detroit,""Mich., assignor to General. Motors-Corporation,Detroit, Mich., a corporation of.

Delaware: x H

Fildnpne, 195s, Ser. No. 726,188

s Claims. (Cl. 261-23) present invention relates to an improved flow control metering valve for a fuel injection system. More specifically the present invention relates to animprovement in the fuel metering valve shown in copending application Serial- N0. 634,915, McDufiie, filed January 18, 1957,

now Patent lid/2,893,711, granted July 7, 1959. V

; \Iheimprovement in the present metering valve con' sists of constructing the same in away which makes its 1 operation substantially. frictionless'which overcomes the hysteresiswhich has occurred in the control of the previ ous type metering valves such as that shown in the MeD uLifie application .Where sufliciently strong controlforcesare available under all operating conditions, the previous type metering control valve will function perfectly satisfactorily. However, inthe mass air flow -type fuel system, shown in the McDufiie case, the forces which will control the actuation of the metering valve are extremely small, particularly under low air flow conditions, therefore, any frictional resistance therein soon reaches a critical value and may, under certain operating conditions, exceed the valve controlling forces.

Accordingly, the present invention is directed to an improved type of metering valve in which a pintle member is mounted 'on a pair of flexible diaphragms in such a waythat the movement of the fuel flow controlling pintle is essentially frictionless and thus fully responsive to even low fuel controlling forces.

The details as well as other objects and advantages of the present invention will be apparent from a perusal of the detailed description which follows.

In the drawings:

Figure 1 is a diagrammatic representation of a fuel injection system embodying the present invention; and

Figure 2 is an enlarged detailed view of the subject metering valve.

Referring to Figure l, a fuel injection system is diagrammatically represented with only sufiicient components to provide a sufiicient environment within which to describe the subject metering valve. The system includes an air induction passage 10 having a venturi 12'formed therein and the air flow through which is controlled by a throttle 14. Induction passage 10 communicates with an intake a manifold or plenum 16 from which a plurality of individual cylinder intake passages 18 communicate with the individual cylinders of the engine. Fuel nozzles 20 are disposed respectively in each of the intake-passages 13 proximate the associated cylinder, not shown.

The flow of fuel to the nozzles 20 is controlled by a metering mechanism indicated generally at 22. The details of metering mechanism 22 as well as other devices which may be incorporated therewith are described in detail in the aforcnoted copending McDuflie application. Mechanism 22 will only be described in the present case to the extent required to indicate the operation and control of the subject improved metering valve.

Metering mechanism 22 includes a pair of diaphragms 24 and 26 suitably clamped between a central casing July 15, 1957.

28and end casings 30 and 32.

' 'Ihe diaphragms are re-I spectively connected to the legs 34 and 36 of a U-jshaped yoke member 38. Legs 34 and 36 are respectively dis posed on opposite sides of a sealed central wall 40 ofcas- 7 ing 28. Leg. 36 is considerably longer than leg 34 and extends downwardly 'and. terminates in a free. end 42.

End42 of leg 36 is adapted to coact and control the improved'metering valve. indicated generallyat 44. For further details with respectto 'yoke38: refer'to copending application Serial No. 671,933,:McDuffie, filed Diaphragm 24 coacts respectively with casings 28 and 30 to define chambers 46 and '48. Casing 30 has an elbow 50 to which a conduit 52 is connected. The other end of conduit 52 communicates with venturi 12 whereby" a vacuum signal proportional to the massof air flow through induction passage 10 is transmitted to chamber 46. Chamber 48 is open to the" atmosphere through: a port or passage 54. Thus, as air flow through inductiori passage 10 increases, an increased vacuum force is'transmitted to chamber 46 causing the'diaph'ragm 24 to be moved to the left and, as will later be discussed in greater detail, increase the flow of fuelthrough metering valve Diaphragm 26, on the other hand, is exposed" to the 'fuel pressure drop across metering valve 44. As fuel flow through valve 44 increases the pressure drop increases causing diaphragm 26 to urge the valve in'fu'el flow de-f V creasing direction in opposition to venturi vacuum.

Apropos of fuel pressure actuation of diaphragm 26, fuel from metering valve, 44 is admitted to a first "cham berj56 defined by casing 28 and diaphragm 26 and acts on the-left side of thediaphrag'm. Fuel from chamber 56 flows through a passage 58 and an orifice 60 to passage 62 where it enters a second chamber64 formed by dia-" phragm 26 and end casing 32. Since the chambers 56- and 64 are interconnected by the orifice 60, theg'fuel" flow therebetween will create a pressure difierent'ial across diaphragm 26 which is proportional to the rate of fuel flow. Thus, the pressure on the left side of diaphragm- 26 will increase with an increased fuel flow rate.

Fuel from chamber 64 will flow to conduit 66-w he'ref the same will be delivered'to the fuel'nozzles 20. Thus the quantity of fuel delivered by metering valve 44 to nozzles 20 is differentially determined by mass air flow and fuel flow such that as mass air flow through venturi 12 increases, the quantity of fuel delivered to the fuel nozzles will likewise increase.

Metering valve 44 can best be considered by referring to Figure 2. The metering valve comprises a casing 70 having an axial fuel inlet passage 72 which is supplied with fuel under pressure through conduit 74 from a pump 76 which in turn draws fuel from a fuel tank 78. Fuel inlet passage 72 terminates in a casing boss 73. Passage 72 communicates with an enlarged counterbored portion 86 of the casing from which an outlet passage 82 is adapted to supply fuel to diaphragm fuel chamber 56.

Casing 70 is further count'erbored at 84 to receive a stepped sleeve 86. Sleeve 86 is adapted to fit within counterbore 84 and at one end thereof clamp a first flexible diaphragm 88 between the right end of the sleeve and a shoulder 90 of the counterbore. A cover plate 92 is adapted to clamp a second flexible diaphragm 94 between itself and the left end of sleeve 86.

A pintle member 96 is centrally supported by the diaphragms 88 and 94 and includes a reduced end portion 93 adapted to coact with the flatted end of casing boss 73. In this way end portion 98 controls the quantity of fuel flow through passage 72 in accordance with the axial position of pintle 96. The left end 100 of pintle 96 includes a hemispherical projection 102 which is adapted to coact with free end 42 of leg 36 of yoke 38. To insure the positive movement of pintle 96 in both directions,

menialn nt e' q tii the meteringyalve. 1

clockwise direction in accordance with the aforenoted I forces supra pintle; 9 6 .jwill-"move to. the left; or:

to fueliiinlet 'zshiiaber,

g aai gare asiaeaa 1ne metering U V ll he suhstantially ineaea es's' inf operation, it. also necessary that the. valve befstatically. balanced;

t6 afiect the "position thereof." *As already-noted, the valve controlling forces are intended to he -1imiteditoithose f'Ihe etfectivel ea diiferential betvlcen these diaphragms v in h q ishlh ree r gvi s d mat Specie fically through inlet: passage 72 to chamber 80. Due, to

' hisaresne si' sa, the u e u e insm p fl endporf'tion 98 is'greater than the unit pressur e actingon- 1 'diaphragms 8 8' fand94. -However, the diaphragm area 9 l v V w ei g .i PQ Q P iq ma i l a P Q 'QF QmFD 3G quantity of fuel flow through'said inletj passage said;

difir mi i f hssg es t an pp si ,ful P e tsuge forces acting onthe diaphragm into balance Vunafiected by fuel flow through V Thus theipresent meteringval ve construction is: a theta frictionless 1 and statically balanced fuel metering valveisiachieved which is significantly more compatible. the low control f orces available under certain oper ating conditions. thanhas been any previous type metering passages communicating said intake passage with the individual cylinders of the engine, a fuel nozzle disposed fi e w l l f rl A tingfthe pt Ie n dis aragmsrsssna t a p entithattthe axialun emcntith ereof willrbeh sand- 1 115 ret s r r p w i w in 7 151 55 8 fl p- 194. Suitably attached to 'pintle 96' and resiliently op'erativcly connects arm 36 and the pintle.

Thus'as arm 36 is moved in a clockwise or counter- "4, r in-each of said plurality of intake passages, and" a fuel metering mechanism responsive :to the quantity of air flowthr'ough said venturi forsupplyin'g fuel to said nozzres in proportion to said air flow} saidlmetering mechanism including a"-fuel-inlet passage,'a fueloutlct passage, a a

; pintlervalve member axially adjustable with respect to' ,said inlet passage to control the quantity of fuel' flow' the'rethrough, said pintleg-llfeingiiadially supported f-by ay pair at flexiblefdiaphrlagm.membets, and a'contnol ann". operatively'connected' t'osaid pintle" and adapted'itd the'axial position oi; rsaid'pintlerins'relation {0153i inlet]: passage 'in -accordancei"withithe-masstroiair; flojnnthr 2 j 7 V the vventuri, the areas of said diaphragms arrangedsostliat 1 the axial' position oii said pintle -valrvermemher is iun-o 7 aflected byfuel'"pressnre'acting'onjsaiil diaphragrnsand pintle.

2. A fuel metering valve comprising a first fcasing hav= ing a counterbored portion, a' boss extending within said 7 v n nion,v a fuelinle p sa e. te di v thrau h i 'i b s fbrmedin saidr ount b rr r pa r qffiex b q @2 g i; 7

V shoulder; acoveriadaptedto clamp thentheribfisard dia- V ier cent al visupp -ed and communicatingiwith said counterboreija; shoulder asleeve d spo l fi m m tbfififil ad ts p p v y elamp n Of S d i ph g aid:

p agms-ag instit o he nd f s r klw' c; a mam an ai qialz arasms' 9 l 3, Ainel meter'i g: .valve as set forth in cljainr 2- inwhich the unit fuel pressure acting onlthe pintle' and' smaller diaphragm is substantially balancedlby the;

40 fuel pressure acting on the larger diaphragm :ge forming device for an internal combustion 7 Q References, Cited in the file of patent V r UNITED SIATESPATENTSf a 5 2,525,083 Str'esen-Rcuter e Oct., 10,1950; 2,626. 789: 'Mock Jan. 21; 1953.

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