US2899951A - Fuel cut-off device for fuel injection system - Google Patents

Description

Aug.- 18, 1959 E. oLsoN ETAL FUEL CUT-oFF DEVICE FoR FUEL INJECTION SYSTEM Filed March 25, 1957 2 Sheets-Sheet l ATTORNEY ited Staes FUEL CUT-OFF DEVICE FOR FUEL INJECTION l SYSTEM Elmer Olson, Ellsworth A. Kehoe, and Lawrence C. Derrnond, Rochester, N.Y., assignors to General Motors Aatent Oilice Corporation, Detroit, Mich., a corporation of Dela- The present device relates to a fuel control device for a fuel injection system and more particularly a device in which fuel flow to the engines cylinders s 'interrupted during certain decelerating conditions.

lDeceleration fuel cut-olf devices are well known but such devices particularly as applied to fuel injection systems have for various reasons not functioned satisfactorily. Fuel cut-olf devices which have utilized manifold vacuum as a fuel flow interrupting control force, as shown in Serial No. 608,797, tiled September l0, 1956, have been particularly trouble-some in practical applications. Manifold vacuum type fuel cut-olf devices are designed to interrupt the fuel flow when the manifold vacuum reaches a given value indicative of deceleration. With the engine idling, as when in neutral, and thel throttle suddenly opened then closed, the manifold vacuum will usually equal or exceed the value required to shut olf the flow of fuel with the result that the engine will stall. This same type of thing occurs when shifting a synchromesh type transmission through the various gear ratios, in this case, when the engine is accelerating and then the clutch depressed to change gear ratios, the vacuum rises rapidly due to releasel of engine load causing Vthe engine to tend to stall. In the fuel cut-olf mechanism is set to functiony at a suiliciently high manifold vacuum level to avoid ythe neutral kick or ratio change stalling, as described, the fuel cut-olf mechanism wil be inetlectiveto cut off fuell flow ybelow-relatively high vehicle speeds. To illustrate, a normal deceleration fuel. cut-off device might be designed to operate on twenty inches of vacuum. During the neutral throttle kick asdesc'ribed,` manifold vacuum might easily go to twenty-three inches of vacuum actuating the fuel cut-olf device to stall the engine. Essentially, the same phenomena would occur in changing gear ratios. If this situation was corrected by setting the fuel cut-olf device to function at some value above twenty-three inches, the fuel cut-olf function would be absent under 40 to 45 miles per hour vehicle speed since under these speeds manifold vacuum wouldnot be likely to reach orv exceed twenty-three inches of vacuum. -Other devices have been .utilized to delay the actuation of the vacuum operated fuel cut-oil devices but these additions have made the operation of the vrfuel cut-off mechanism too slow to give satisfactory operation.

The present device avoids the above diiculty by using a solenoid controlled fuel cut-olf valve rin conjunction with series connected throttle andVV engine speed control switches such that with the throttle closed and the engine operating above a given speed, the solenoidv valve will cut olf the fuel supplied to the engine cylinder. Below.' a given`v engine speed or with the throttle switch open the solenoid valve will be rendered inoperative to restrictV fuelilow.l j .j I j f .1 l

In additionv to ,the novel combination of. speed and throttle switches in controlling fuel injection fuel flow, la unique type of solenoid actuated,valve` provided. e,

lOther advantages and objectsv of the presentnvention of a manual valve is necessarily a comprise setting and is neitherl correct when the engine is hot nor when it is cold. Further, such a manual valve usually requires frequent' 2,899,951 Patented Aug. 18, 1959 will be apparent from a perusal of the detailed description which follows.

In the drawings:

Figure l is a diagrammatic representation of a fuel injection system embodying the subject deceleration fuel cut-oi device; and

Figures 2 and 3 are enlarged views of the solenoid control valve.

In the diagrammatic representation of Figure l, a fuel induction passage is shown generally at 12 and includes a venturi 14 posterior of which is a throttle valve 16A fuel supply source is indicated generally at 18 and in-` cludes a float controlled type valve mechanism 20, an

engine speed responsive pump 22 and a fuel metering valve generally indicated at 24. The metering valve is under the control of a diaphragm 26 through a linkage mechanism 28. The preceding elements and devices function in the same manner as described in copending application 646,081, filed March 14, 1957 by L. C. Derwood.

It will suffice to note that fuel is supplied to the metering valve 24 by pump 22 under a pressure which is proportional to engine speed. Valve 24 then delivers fuel to a distributor supply line 30 in accordance with the actuation' of the Control mechanism 26-28 which primarily is under the control of vacuum in passages 32 and 34. The vacuum in passage 32 is proportional to the mass of air flowing through the induction passage 12 and hence causes diaphragm 26 to move valve 24 to a position increasing the llow of fuel to line 30 as said mass air ow increases. Manifold vacuum is available in conduit 34 when the throttle 16 is closed as described in copending application Serial No. 608,797'Olson, filed September l0, 1956.

An idle air bypass network is indicated generally at 44 and includes a passage l46 communicating with the induction passage anterior of throttle 16, a passage 48 communicating with the induction passage posteriorly of the throttle and a passage 50 interconnecting passages 46 and 48. Normally a manually adjustable valve is disposed in such network and which valve is adjusted for an average idle air flow. It is apparent that such average adjustment adjustment due to normal engine operation.' In the present Vdevice a thermostatically controlled valve 52 is interposedri'n passage 50 and is adapted to accurately control the idlerair ow in accordance with thervarying requirementsjof the engine as determined by engine temperature.

In order that the temperature responsive valve accurately reflect engine temperature, a housing 54, Within which the thermostatically controlled valve 52 is disposed, is

mounted upon the engine cooling'system as described in copending application 650,389, led April 3, 1957v and now`Patent No. 2,848,986. A thermostat 58 is mounted i in housing '54 and iixed at one end 60 to the housing and at theother' en d to the valve shaft 62. yIn order to provide 4arrinitial cold running setting for the valve 52 an bypassed around throttle valve 16 insuring sufficient air to provide lfaster than normal engineidling speeds under cold conditions. Through this device-the normal fast idle cam, which sets the throttle idling position in accordance with engine temperatures, is eliminated. Ac-

cordingly, under idling conditions the throttle may always be closed with the variations in the quantity of the idlingl j mixture being controlled in the idle air bypass network las described.`

TVO/:secure adequate fuel enrichment when the engine is running cold additional means are provided to supplement the normal venturi vacuum signal acting on the upper side of metering valve control diaphragm 26.

Devices which have been used heretofore to insure an enriched starting mixture have been unsatisfactory from economy and performance standpointssince they are active tothe same extent irregardless of engine temperature. The result'of this' type of temperature insensitive f operation is to supply an overly enriched starting mixture to a partially warm engine wasting fuel and making engine performance sluggish. To eliminate this problem, the present device provides vacuum boost signals which are modulated in accordance'with engine temperature and which thus preclude overenrichment of the starting mixture since the latter is always keyed to engine temperature.

In order to provide a' metering diaphragm modulating signal a conduit 7 0 connects 'the metering diaphragm to a point posterior to the throttle 16. In the diagrammatic disclosure of Figure l a branch 71 of conduit 70 connects with idle air bypass passage 48, which as noted, connects with the induction passage 12 posteriorly ofthe throttle 16. A first valve device 72 is disposed in conduit 70 for controlling the amount of manifold vacuum transmitted to the diaphragm 26. Valve device 72 includes a member 74 slidably disposed in casing 76 and which member is suitably articulated to the thermostatically controlled lever 66. Thus, when the engine is cold the valve will be in the position shown in Figure l transmitting the maximum amount of manifold vacuum available in line 71 to the diaphragm 26. As the engine warms lever 66 will rotate in a counterclockwise direction moving the member 74 to a position modulating or gradually cutting olf they amount of manifold vacuum superimposed on the diaphragm 26. Device 72 modulates the vacuum force by providing the member 74 with a suitably tapered portion 78 disposed between lands 80 and 82. Land 80 has a passage -84 therethrough for transmitting the vacuum force to diaphragm 26. utilized to reduce the vacuum force available to act on the diaphragm and in this way seive as an orifice in line 70.

An additional valveV device 90, in parallel with valve lf desired, passage 84 may be" 72, is disposed in the manifold vacuum circuit and is adapted to provide Vadditional manifold vacuum during the cranking operation of the engine under whichcondition a particularly rich starting mixture is desired. Device 90 likewise includes a member 92 slidably disposed within casing 94 and which also includes a tapered section 96 for metering the manifold vacuum ilow to the diaphragm in inverse proportion to engine temperature. Valve device 90 also has associated in series therewith a ball check valve 100 which upon the starting Vof the engineris adapted to cut off the manifold vacuum flow through the branch circuit 162. Thus during cranking oftheengine valve devices' 72 and 90 are each trans'- mitting'a manifold vacuum force to theV diaphragm 26.

As -soon as the engine begins to run, however, the crankingmodulating signal is cut off and manifol-d vacuum modulation takes place only through valve 72. Y

In theevent a warm engine is re-started thegsliding members 74 and 92 will be in a position to modulate.. the manifold vacuum to supplement venturi vacuum or toeliminate theV manifold vacuum force entirely vdependent on the residual engine warmth. The valve devices 72 andA 90 -are shown in their cold running positions.v

As noted with increasing engine temperatures the sliding members 74and 92`are gradually shifted to the left, as viewed'in Figure l, by thermostatically controlled lever 66to reduce and ultimately eliminate the 'force of manij.

fold vacuum on4 diaphragm 26.

In orderv to cut off the flow of fuel in the cylinder fuel supplyingconduit 30 under'certaindecelerating condi;

Vto the cylinder supply lines 120.

member 112 `disposed on top of a 'fuel distributing manifold or spider 114. As best seen in Figure 2 the fuel manifold comprises a casing having a boss 116 depending therefrom and to which is suitably connected fuel conduit 30. The manifold casing 114 also includes a plurality of circumferentially spacedV radial bosses 118 each of which is connected to a fuel line 120 leading to an individual cylinder of the engine. Under normal operating I conditions the metered fuel from valve 24 enters the fuel manifold through boss 116 Vand is equally distributed to` upper position so as to move the metering valve 134,

out of flow restricting engagement with fuel passage 122.

While armature k13:0 may be held in its upper or normal restricting position by means such as a spring, the present device avoids the necessity of such means and instead utilizes the pressure of fuel in passages 122 and 124 f which acts against the tapered end 136 of the valve as well as the tapered surface 140 of the armature to retain the latter in its retracted position. It is apparent that by using fluid pressure to retract the armature Va simplied and'cheaper type structure results.

The .solenoid 112` is actually mounted on manifold V114 by a plurality of studs `142 which extend through the manifold intermediate radial passages 126.v Studs 142v thread in openings 144 ina ylower end plate 146 which is peripherally relieved at 148 to provide an annular lip 15). Solenoid casing 152 ris bent radially inwardly at its respective ends yto clampinglyl engage end plates 146 and 154.V Lower end plate 146 includes an upstanding boss 156 tightly surrounding which is an armature supporting` End plate 146 is centrally relieved at 164 to receiveV aboss 166 formed on fuel,manifold` 114., An yannular recess v168 surrounds boss 166 and receivesaseal 170 to'. i prevent the leakage of fuel between the solenoid and fuel manifold.

v The control of solenoid valve 130--134 is through .theV

combined effects ofa throttle controlled switch 172 and The throttle controlled switch 172 may beof. any co'n-H venient type and inasmuch as it does not, per se,con`v stitute `the subject matter of the present invention, is not -shown in detail.

tions afuelrcut-otf device indicatedgenerally at'110 'isprovided. This'deviceincludes a solenoid actuatedvalvel wereQprovided` to correct therefore thev provision of a throttle controlled; switch only for actuating the solenoid 112,would result in frequentpengine stalling since the throttle might remain closed until the engine had passed n well below the speed where fuel was passing unburned through the engine.l Toavoid this situation the vadditional switch 174 is provided and which switch is adapted' to be closed above a certain engine speed: Here againA the engine speed" responsive switch mechanism 174 is Y not shown infdetail since any well known type ofspeed switchV may berutilized .to perform the intended function.

For instance, switch 174mayV be operatedk by'a ily-ball governor, generator voltage, etc;

The essential requirement of switch 172is thatit be closed onlyV when the throttle is closed as will be Athe case when the vengine is -decelerating `under conditions wasteful of fuel. Unless, however, means.

Engine speed switch 174 may be adjusted to open at speeds below 3() miles per hour interrupting the ow of current to the solenoid 112 irregardless of the fact that the throttle control switch 172 might be closed and thereby insuring that the `fuel cut-olf mechanism will function no longer than necessary.

Power source 176 is connected to the speed control switch 174 through a lead 178, the speed switch to the throttle control switch through a lead 180 and the throttle control switch to the solenoid controlled valve through a lead 182 with the solenoid being grounded through lead 184.

The operation of the `deceleration cut-off device is briefly as follows: with the throttle valve 16 closed and the engine operating above a given minimum speed the solenoid valve 112 will interrupt the ilow of fuel from the fuel manifold 114 until such time as the throttle is again opened or the engine speed drops below a given value as described.

We claim: v

l. A fuel injection system for an internal combustio engine comprising an air induction passage, a venturi formed in said passage, a throttle valve in said induction passage posterior to said venturi, a source of fuel under pressure, conduit means communicating said fuel source with the cylinders of the engine, a valve disposed in said conduit means for metering the quantity of fuel supplied to said cylinder, a device for controlling said valve, conduit means connecting said valve control device with said venturi to actuate said device in accordance with the mass of air owing through said venturi, a valve device disposed in said conduit means intermediate the metering valve and cylinders for interrupting the flow of fuel, said va'lve device comprising a solenoid, a throttle controlled switch and an engine speed responsive switch in series with each other and with said solenoid, said valve device blocking the flow of fuel through said conduit means when said switches are closed to energize the solenoid.

2. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi formed in said passage, a throttle valve in said induction passage posterior to said venturi, a source of fuel under pressure, conduit means communicating said fuel source with the cylinders of the engine, a valve disposed in said conduit means for metering the quantity of fuel supplied to said cylinder, a device for controlling said valve, conduit means connecting said valve control device with said venturi to actuate said device in accordance with the mass of air flowing through said venturi, a valve device disposed in said conduit means 'intermediate the metering valve and cylinders for interrupting the ow of fuel, said valve device comprising a solenoid, a throttle controlled switch and an engine speed responsive switch in series with each other and said solenoid, said valve device blocking the flow of fuel through said conduit means when said switches are closed to energize the solenoid, a passage for bypassing air around the throttle when closed during idling, a valve in said bypass passage, and temperature responsive means actuating the bypass valve to render the quantity of idle air inversely proportional to engine temperature.

3. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi formed in said passage, a throttle valve in said induction passage posterior to said venturi, a source of fuel under pressure, conduit means communicating said fuel source with the cylinders of the engine, a valve disposed in said conduit means for metering the quantity of fuel supplied to said cylinder, a device for controlling said valve, conduit means connecting said valve control device with said venturi to actuate said device in accordance with the mass of air flowing through said venturi, a valve device disposed in said conduit means intermediate the metering valve and cylinders for interrupting the flow of fueLl, said valve device comprising a solenoid, a throttle controlled switch and a speed responsive switch in series with each other and said solenoid, said valve device blocking the flow of fuel through said conduit means when said switches are closed to energize the solenoid, a passage for bypassing air around the throttle when closed during idling, a valve in said bypass passage,'a conduit communicating said control device with the induction passage posteriorly of lthe throttle valve, valve means in said latter conduit for modulating the manifold vacuum acting on the cotnrol device, and engine temperature responsive means operatively connected to the bypass valve and the valve means to render the llow through both inversely proportional to engine temperature.

4. A fuel injection system as set forth in claim l in which said valve device includes an armature having a valve element formed thereon, said armature and element being responsive to the fuel pressure and normally held thereby in a position permitting the free flow of fuel through the conduit means.

5. A fuel injection system for an internal combustion engine comprising an lair induction passage; a Venturi formed in said passage; a throttle valve in said induction passage posterior to said venturi; a source of fuel under pressure; conduit means communicating said fuel source with the cylinders of the engine; a valve disposed in said conduit means for metering the quantity of fuel supplied to said cylinder; a diaphragm device for controlling the metering valve, a conduit connecting said diaphragm device with said venturi for controlling said valve in accordance with the mass of air flowing through the venturi; a fuel distributor; said conduit means including a passage connecting the metering valve with said fuel distributor for delivering fuel to the distributor, and a plurality of passages leading from said distributor, said passages respectively communicating with the individual cylinders of said engine; a chamber in said manifold communicating with said delivery passage and said plurality of passages, valve means in said chamber adapted to cut olf the ow of fuel through said manifold, said valve being responsive to the pressure of the fuel flowing through said distributor and normally moved thereby to a position permitting uninterrupted fuel flow to the passages, solenoid means adapted when energized to shift said valve to a position blocking the flow of fuel through the manifold, a source of power for energizing said solenoid, a throttle actuated switch and an engine speed responsive switch connected in series with said power source and solenoid, said switches being adapted to energize said solenoid during throttle-closed deceleration of said vehicle.

6. A fuel injection system for an internal combustion engine `as set forth in claim 5 in which said solenoid includes an armature operatively connected to the valve means, said armature having a surface exposed to the fuel pressure in said chamber for moving the valve means to permit the flow of fuel through the distributor.

No references cited.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION E +G 1, No., 2,899,951 I Elmer Olson et el.

August 18, 1959 It is hereby certified that error appears in the prin-ted specification of the above numbered patent requiring correct-ion and that Jche said Letters Pai-,enrl should read as corrected below.

` Column l, lille` 38, for "ln" read i-K if' .m5 @011mm g, 1in@ lo, #for "Derwood" read Dermozid nu; line 4l, for "comprisc-:fn read \A compromise f1-o Signed and sealed this' 31st day of' Mey 1960.,

(SEAL) Attest:

KARL Iig AXLINE Attesting OfceiI ROBERT C. WATSON Commissioner of Patents

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