US2942862A - Fuel injection metering control mechanism - Google Patents

Description

June 28, 1960 L. c. DERMoND FUEL INJECTION METERING CONTROL MECHANISM Filed latch 24, 1958 INVENTOR d w w m 7 w i ATTR/VEY 2,942,862 FUEL INJECTION MEI'ERING CONTROL MECHANISM Claims. (Cl. 261-69) 'Ille present invention relates to a fuel injection system of the mass air ow type utilizing a metering control valve United States Patent O disposed in a fuel chamber and which valve is controlled a.

by a diaphragm device responsive to mass air flow:

'More specifically the present invention relates to a sim-V pliiied linkage arrangement through which the fuelmeterlng valve is controlled. As described in copending appli'- cation Serial No. 591,889, Dolza, filed June. 1.8, 1956, the metering valve linkage mechanism is basically controlled by a mass air ow responsive diaphragm device the operation of which is modied by a power enrichment device. The latter device is adapted to provide an economical fuel ow range for normal light load engine operation at the same time insuring increased fuel flow under high power demand situations. The earlier means for achieving this fuel ow rate variability in the metering valve linkage was 'by means of providing a shiftable fulcrum controlled by a manifold vacuum actuated servo. Thus by shifting the fulcrum the mechanism advantage of the linkage system was varied torelatively increase or decrease the fuel liow rate.

This earlier vmeans for making the linkage operation responsive to engine load while operative has been modified in accordance with the present teaching to better facilitate control by the relatively low vacuum control forces available to actuate the meter valve diaphragm. Since` such mass air tlowgenerated vacuum control force is relatively low, particularly under low air flow conditions, any hysteresis in the linkage system due to friction,

looseness, etc. tends to modify or delay the control of the metering valve. The present 'invention is directed towardV reducing such hysteresis and simplifying such linkage systeniparticularly in relation to'its coaction with the power enrichment device. y A v In the present invention engine load modifications of fuel liowrates are 'achieved by, a greatly `simplified lever system for varying mechanical advantages. The lever system also includes a spring the rate of which is uniquely varied toY further facilitate changes in engine loadvaried fuel rates.V

Further objects and advantages of the present invention will be apparent from a perusal of the detailed description which follows.

- YIn the drawings:

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

Figure 2 is `an enlarged perspective view of the improved metering valve linkage system. l

VThe fuel injection system in general comprises an air ber 14I supplied' by the airintake and a plurality ofin- 'ICC dividual intake passages 15 leading from the plenum chamber 'and respectively communicating with each of the cylinders of the engine. A fuel metering device is shown generally at '16 and includes a fuel chamber 18 having an inlet 20 the flow through which is controlled by a conventional oat controlled fuel inlet valve 22. A pump 24 is submerged in the fuel chamber and is adapted to pressurize the fuel and supply the same through a conduit 26 to a metering valve 28. A plurality of fuel conduits 30 communicate supply conduit 26 with individual fuel nozzles 32 disposed in the intake passages 15 proximate the engine cylinders.

Metering valve 28 includes a ball element 34 disposed Within a recess 36 and which element is adapted to be moved upwardly by the uid Vunder pressure in conduit 26 whereby a portion of the supplied fuel will be bypassed through radial passages 38 back to the fuel chamber. Op-

posing the fuelrpressure opening movement of the valve element 34 is a control rod 40 centrally fixed at its otherv endV to Ya diaphragm 42 mounted in the cover wall 44 of the fuel chamber 18- and peripherally clamped to said` intake lpassage 10. As the mass .or quantity of air flow increases through intake passage 10 with an opening of throttle valve 12, the vacuum force in chamber 60 and conduit 58 will be increased causing the diaphragm 42 to be moved downwardly to oppose the fuel pressure-opening of the valve element 34 and to reduce the fuel being bypassed back to chamberV 18. The result of the increase in mass air ilow is therefore a corresponding increase in the quantity of fuel supplied to the nozzles 32. i

The power enrichment mechanism 50 is provided in order to insure maximum fuel economy under normal operating conditions and increased fuel flow under conditions ofrhigh power demand. 'Ihis mechanism includesa servo piston 64 slidablymounted in a casing 66 and dening therewithl a chamber 68 connected through a conduit 70 with manifold or plenum 14. A spring 72 norf mally urges the piston 64 in an upwardly direction.VY A bell crank lever 74 is pivotally mounted at 76 and includes an arm 78 articulated to piston 64 by a link 86. The other arm 82 of bell crank lever 74 is articulated to lever 48 which, as already noted, operatively interconnects dial phragm control rod 40 and the valve element 34.

Lever 48 and bell crank ann 82 are pivotally connected by a pin 88. A spring is looped about pin 88 and includes a first leg 9,2 biasing against arm 82 and a second leg 94 biasing against the underside of lever 48. Spring 90 rotatably biases lever 48 in a clockwise directionrelative to arm 82. This action is then in opposition to the vacuum force in diaphragm chamber 56, ,the latter tending to maintain valve element'34 in a seated position. The counterclockwise force of spring 90 is such that under normal operating conditions, i.e. pin 88 in rightmost position, it will counteract the weight of diaphragm control rod 40 and lever 48. y on diaphragni42 are relatively small it is necessary' to compensate for the-'Weights of elements acting thereon lest Patented June 28, 1960:

vSince the vacuum control forces acting operation.

they upset the control Vof metering valve 34. Unless compensated by spring 90, the weight of rod 40 and lever 48 would urge valve 34 in a direction reducing the fuel bypassed and thereby'increasing the fuel supplied to the nozzles. Y Y

A pair of spaced stops 84 and 86 are provided against which the'free end of lever arm 78 is adapted to abut in accordance with the position of piston 64. Under normal operating conditions the manifold vacuum in chamber 68 is sufficiently high to overcome the spring 72 to move the piston downwardly causing the lever arm 78 to abutagainst theloiver or economy operation stop 84. 'Ihis'movement of lever Y74 causes the pivot point 88 between lever 418-and` arm 82 to move to the right increasing the-torsion on spring 90 and causing the latterfto fully offset'the weight of lever 48 and rod 40, supra. The -rightward movement of pin 88 V`also shifts the fulcrum point' of the lever system such that the mechanical advantage of the vacuum force acting downwardly on rod 40 is relatively decreased with Vrespect to that 'of the fuel pressure-urging valve 34-upwardly. The result of increased torsion on spring 90` and increased resultant effect of fuel pressure Von lever 48 is to cause valve 34 to bypass morevfuelther'ebyleaning out theY fuel-airmixture Vfor more economical Yengine On the other hand, demand, such as occur with asuddenV depression of the accelerator pedal, the manifold vacuumlin chamber 68 is reduced Vsuiilcie'ntly to permit the spring 72 to raise pistou -64 until lever 78 abuts the upper or power stop 86 shifting the pivot or V,fulcrumpoint `883:0, the left. This action' decreases the torsion on spring 90 and adds the Yweight of rod,40and lever 48 to the vacuumv force tending to'close valve velement 34'.` fLikewise theV vacuumV force acting throughV rod 40 is Yrelativelygincreased with respect to the fuel Yforce acting on valve 34,- again dueV to changes in mechanical advantages, whereby fuel ow to nozzles 32 is increased. It is apparent that this latteroperation provides fuel enrichment and hence additional power until such time as the load on the engine is suitably decreased. A Y n Anovel idle Yfuel new control device is shown 'with the illustrated fuel injection system and forms thezbasis of copending application of Dermond S.N. 723,196Y filed March 10, 1958. The idle fuel; control device willnow be described briey. Y

YA boss 93 is formed onthe. fuel chamber coverY 44.V

under conditions of? highv power therefore to vary the rate of fuel flow through the metering valve.

Thus, tocontrol idle fuel flow an adjustable valve element 96 is provided in boss 93 and includes a tapered end portion 98 adapted to cooperate with an atmospheric vent port 100. The vacuum level in the fuel chamber 18 may thus be varied in accordance with the degree of opening of said atmospheric port. With the valve 96 completely blocking the atmospheric bleed port 10|), a maximum vacuum force Will act Within the fuel chamber causing a corresponding maximum pressure drop across valve element 34. As the atmospheric vent port 100 is progressively opened by-valve 98, the pressure within the fuel chamber approaches atmospheric reducing the pressure drop across valve element 34 and thereby increasing the fuel flow to the nozzles under idling conditions.

In this'way a simple device isprovided forV controlling idle fuel ow by utilizing'a control force otherwise available in the system. It is apparent that various structural modifications may be made in the subject invention with- Vin the scope of the hereinafter appendedclaims.

responsive device operatively connected to said lever and and is adaptedgto beV communicated withA a suitable Con- Y duit rconnectedv with aV sourceV of manifold-vacuum. As set forth in copending application Serial No. 648,100 Dermond et al., led March V25, 1957,'Y now Patent No.

valve 28 by diaphragm 42. These vapors may be eliminated from the fuel chamber by maintaining a,slight depression Yabove thefuel levelwh'er'eby the vapors are drawn into the-manifold.' 'Ihe manifold vacuum in fuel Y chamber'1Sisreducedtoany desired value `by any suitable oritirc'e 9S which may be disposedY in'boss 9,3.'Y

iadaptedfto-move said element toincrease fuel How (as saidV demand increases, means'biasing said lever ina direction decreasing fuelV ilow'through the valve device, ,and au.

engine` loadresponsive dev/ice for modifying theoperation of said biasing means toincrease .fuel flow under high load conditions and to decrease fuel ow under low loadrcondtions. Y y Y, F f

2.1A charge forming device for aninternal combustion engine comprising a. sourceroflfuel` under pressure, a valve device for supplying metered quantitiesof ffuel to thenengine, said valve device including aV movable valve element, said fuel .under pressure acting-on theV element to decrease `fuel now, andrmeans forcontrolling Vthe actuation,` of "said valve element, said means including a first lever operatively connectedv to said element, an engineY demandV responsive device Voperatively .connected to..

said lever and adapted to move Ysaidpelement to increase fuel flow as saiddemandincreaseaa bifurcated leverhaving one leg .articulatedl tofsaid .hrstV lever, said*Y bifurcated llever `mounted uponV axedpivot,f a'torsion 2,898,096 grantedAugust 4, 1959 it isdesirable-toelimi- It apparent that with the` fuel chamber maintained under a slight manifolddepression,'and-forV the moment ignoring the metering control forcetransmittedby diap hragm controlrodAl), a pressure differential or drop will'exist across the metering control valve element 34 due to the pressure ofthe fuelactingon oneside thereof and the aforenoted manifold vacuunronthe other sidethrough the metering valve-.toY the nozzles 3'2with` otherA control forces remaining substantially-constant aswould be Athe. case `during Vidlingfoperation. By varying lthis pressure diierential aross `element 734,' f itjispossible Y spring operatively connectedbetweensaid first .lever-and i saidY one legofY the bifurcatedlever vand .urging saidlirstV lever in a fuel ow `decreasing direction, and anlengine load responsive device Varticulated tothefother .v leg of said bifurcated lever,,said `devicefbreirig adaptedto rotate the bifurcatedrleverto'varyl-the rateofsaidtorsion spring.

to vary the rate of fuel flow through saidvalve devicerzl Y f 3.A A-charge forming,devicerforaninternal.combustion engine r'comprising a sourceV of fuelunder..piressure,Y a valve drevierforV supplying-'metered.quantitiesfof lfuel.

toV theV engine, saidvalvel devicek including a V,movable valve element, said-fuel under pressure Yacting onfthe Velement -to decrease fuel flow, Vandmea'ns for controlling theY actuation of saidvalve element, isaidimeans includinga lever operatively connectedg-to V sailele rnent,an:enginedemand responsive device operatively connected'rto lsaid lever and adapted to moveV said elementtof/increasevfuel flow as said demand increasesa torsion Vspringe biasing said lever in adirection decreasingfuelfowlthrough the valve device, Vand'an lengine loadV responsiveljdevice adapted to vary the'rate 'ofsaidspringto-increaseY fuelY flow under high loadconditions andto'fdecrease fuel flow under low loadconditions.' rf" "11;1 1% .i

y 4,. A'harge forming device Vas set'. forth in claim 2 in which the engine load responsive device includes a pair of spaced stops, a servo piston articulated to the other leg of said bifurcated lever, a spring member biasing said piston to abut said other leg against one of said stops to decrease the rate of the torsion spring, and means communicating manifold vacuum with said piston whereby under normal load conditions said vacuum will overcome the force of the spring member to move said other 5 and said one leg of the bifurcated lever.

-. References Cited in the le of this patent UNITED STATES PATENTS Armstrong Mar. 19, 1957 2,837,074 Ransom June 3, 1958

Images