US2899950A - dermond - Google Patents

Description

Aug. 18, 1959 1.. c. DERMOND FUELINJECTION ACCELERATION ENRICI-IMENT DEVICE Filed March 14, 1957 5 Sheets-Sheet 1 HTTGIPNE') Au 18, 1959 1.. c. DERMOND 2,899,950

FUEL INJECTION ACCELERATION ENRI'CHMENT DEVICE Filed March 14, 1957 s Sheets-Sheet 2 Z T MU 197' TORI/E Y I Aug. 18, 959 L, M ND 2,899,950

FUEL INJECTION ACCELERATION ENRICHMENT DEVICE Filed March 14, 1957 5 Sheets-Sheet 5 IN V UV TOR. ,fazfga/m 'd flsmaza FUEL INJECTION ACCELERATION ENRICHIMENT DEVICE Lawrence C. Dermond, Rochester, N.Y., assignor to General Motors Corporation, Detroit Mich., a corporation of Delaware Application March 14, 1957, Serial No. 646,083

8 Claims. (Cl. 123-419) 1 expensive mechanism and provides refinements in operation that may not be necessary in all types of engines.

'Accordingly, the present invention represents a simplified type acceleration device which may be utilized with a fuel injection system.

The present acceleration enrichment device utilizes manifold vacuum acting directly on the fuel metering system to provide an acceleration charge. The present device is constructed so that during normal operation manifold vacuum is, in effect, superimposed on opposite sides of the fuel metering valve so as to be balanced and, therefore, to have no effect on the metering system. During acceleration, however, this device causes the manifold vacuum to act differentially on the metering valve to momentarily increase the quantity of fuel being supplied to the engine cylinders.

States atent O In the illustrative embodiment of the present invention I manifold vacuum is connected to the fuel reservoir and to one side of the metering diaphragm so that the vacuum forces normally balance each other. During acceleration manifold vacuum decreases, however, in the present device means is provided in the circuit communicating manifold vacuum to the diaphragm which causes the vacuum to dropat a lesser rate than is the case in the fuel reservoir. As a result a pressure differential is imposed on the metering valve to momentarily enrich the fuel-air ratio.

A detailed description of the present invention will be found in the appended specification and claims.

In the drawings:

Figure 1 shows a fuel injection system embodying the subject invention;

Figure 2 is an enlarged section of the fuel metering system including the subject acceleration device;

Figure 3 is a fragmentary enlargement of the fuel metering valve; and

Figure 4 is an enlarged sectional view of the power enrichment control mechanism. 7

Figure 5 is an enlarged detail view of the air meter.

T he fuel control system, per se, is shown and described in copending applications Serial No. 608,797 Olson, filed September 10, 1956 and Serial No. 608,853 Dolza, filed September 10, 1956, now Patent No. 2,843,098 granted July 15, 1958. Therefore, the system will only be described in such detail as is necessary to illustrate the present invention. An air induction passage is shown at Patented Aug. 18, 1959 "ice 10 and includes a venturi portion 12 posteriorly of which is mounted a throttle valve 14 adapted to control the quantity of air flowing through the system, The air induction passage communicates with a manifold 16 from which a series of ram or intake pipes 18 communicate with the individual cylinders of the engine. Fuel is supplied to the individual ram pipes through nozzles 20 which direct a continuous stream of fuel against the backs of the fuel inlet valves 22. Fuel is supplied to the individual fuel nozzles through passages 24 emanating from a fuel manifold 26 which is in turn supplied with fuel through a passage 28 leading from a metering device indicated generally at 30.

The fuel supplying and metering device 30, as shown in Figure 2, is mounted in a housing which includes a case 32 and a cover 34. A conduit 36 is formed in cover 34 and is supplied with fuel from a low pressure make-up pump, not shown. A float controlled valve mechanism 38 is also disposed in cover 34 and communicates with conduit 36 through a passage 40 to which filtered fuel is supplied in accordance with the vertical position of the valve member 38 as determined by the position of a pivoted float actuated arm 42. In the normal manner, as float 42 is raised and lowered the valve 38 will shut off or admit fuel into a fuel reservoir 44 provided in casing 32.

A constant displacement type pump 50 which is driven at engine speed is mounted in the fuel reservoir and is adapted to pump fuel from the reservoir 44 to a conduit 46 leading generally to a metering chamber 48.

Chamber 48 is separated from the fuel reservoir 44'by a partition 51.. A bore 52 is formed in the casing of chamber 48 and is adapted to support therein a fuel metering valve 54, the details of which are described in the aforementioned'copending application Serial No. 608,853 Dolza. Sufiice it to say that conduit 46 supplies fuel to a chamber 56 defined by valve 54 and a removable plug '58. The fuel passes from chamber 56 through a central conduit 60, formed in a slidable plug portion 62 of the valve 54, .to a ball. check valve 64 seated upon the upper end of the plug 62. Valve 64 blocks the flow of fuel through conduit 60 with a force determined by the rate. of a spring 66 which presses upon the valve. The metering valve 54 also includes a cylindrical sleeve 68 having a plurality of circumferentially disposed ports 70 therein which communicate the fuel flowing around ball check valve 64 to an annularly relieved portion 72 of sleeve 68. The annularly relieved portion 72 communicates with a passage 74 in the casing wall into Which is threaded an adapter plug 76 connecting with the fuel manifold supplying conduit 28.

Sleeve 68 also has a set of peripherally disposed bypass or spill ports 80 above the ports 70. Ports 80 communicate the interior of sleeve 68 to the chamber 48 and thence through a suitable passage back to the fuel reservoir 44. To control the quantity of fuel bypassed through valve 54 back to reservoir 44 and hence the quantity of fuel supplied to the fuel nozzles, a cylinder 82 closed at the upper end is slidably mounted in sleeve 68. The open end of cylinder 82 terminates proximate spill ports80 in sleeve 68. Fuel pressure within the valve body and which, as noted, is proportional to engine speed tends to. move the cylinder 82 upwardly to open ports 80 and thereby bypass fuel to the reservoir.

Alinkage mechanism indicated generally at and controlled by a diaphragm 92 exerts a force on top of the valve, as generally described in the aforementioned copending application Serial No. 608,853, which is proportional to the quantity of ,air flowing through the system. Thus it will be seen that the quantity of fuel supplied to the nozzles 20 by metering valve 54 is proportional to the 3 differential effect of engine speed, as manifested by fuel pressure, and the quantity of air flowing through the system, as manifestedby vacuum acting on diaphragm 92.

In order to insure that'a'n enriched fuel air mixture is present when the engine iscol'cl, an 'enrichment device'indicated generally at- 96 is provided. Device 96 includes a diaphragm 98'mounted in a casing 100. A rod 182 is centrally fixed to diaphragm 98. Rod 102 is articulated to a lever 104- pivoted at 106 and intermediate the ends of which lever there is articulated anadditional rod 108. The other end of rod 108 is articulated to another pivoted lever 110 the free end 112 of which provides a fulcrum for a lever 114. Lever 114 is connected at one end to a rod 116 which is operated ina vertical direction by the diaphragm 92. The other end of lever 114 engages the top of metering valve plunger 82 such that as the diaphragm 92 moves: upwardly withincreased air flow through theinduction passage, lever" 114-will-pivot about fulcrum 112 and-thereby depress plunger 82 closing the metering valve spill ports 80' toincreasethe; quantity of fuel supplied to the cylinders;- 1

Enrichment diaphragm 98' is biased to' the left by a spring member 120 which causes the pivoted lever 104 to abut an adjustable stop 122 to position the metering valve linkage as shown in- Figure 1. Manifold vacuum is adapted to be communicated, by means later to be'described, to the right side 124 of the diaphragm chamber under normal operating conditions and overcome the force of spring 120 to shift the pivoted lever 104 against another adjustable stop 126 which in turn shifts the adjustable fulcrum 112 in a counterclockwise direction to reduce the mechanical advantage of the metering valve actuating lever and thereby position the fuel metering linkage system for most economical operation.

An additional lever 128 is pivotally mounted in the metering control device 30 and has one end adapted to engage the top of the metering plunger 82 and the other end articulated to a link 130. Link 130 has fixed to its other end an armature 132 of a solenoid or servo device 134. The solenoid 134 is connected through a lead wire 136 to the ignition system, as described in Serial No. 608,853, in such a way that when the starting. motor is energized solenoid 134 is also energized moving armature and rod 130 upwardly and in .turndepressing the meteringplunger 82 to insure maximum fuel flow to the cylinders during starting of the engine. When the startinglmotor is deenergized solenoid 134 is also deenergized so that a spring element 138 moves the armature 132 to its lower position moving the lever 128 out of contact with the plunger 82.

An enrichment control device indicated generally at 140 is adapted to control the cold or maximum power enrichment device 96. Device 140 includes a casing142 suitably bored to slidably support a shiftable member 144 having a piston 146 disposed at one end thereof. Piston 146 and casing 142 define a chamber 148 in continuous communication with engine manifold vacuum which tends to move the member 144 downwardly. A lever 150 is mounted on a shaft 152 rotatably supported in casing 142. One end of lever 150 engages an enlarged portion 154 on the sliding member 144 such that thele-yer 150 and shaft 152 are adapted to be rotated as the sliding member moves Within its casing bore. .A thermostatic coil 156 is connected to the slidingmember 144, either directly or through lever 150, such that when the. coil is cold it retains the member in its upper position permitting the member to be moved downwardlyunder the influence of manifold vacuum as the coil is heated in the manner described in copending application Serial'No. 608,853.

An additional bore 160 is formed in casing 142 and includes a shoulder 162 upon which a ball check valve 164 is resiliently retained by a spring 166, the otherend of which seats against a plug 168 closing one endof'bor'e 160'. Casing 142 has a passage 170 formed therein'which is adapted to communicate bore 160 with a manifold vacuum passage 172. An additional passage 174 is formed in casing 142 and communicates bore 160 with vacuum passage 176 leading to the enrichment device 96. In the position shown, ball check valve 164 prevents manifold vacuum from being delivered to conduit 176. A stud member 180 is slidably mounted in areduced portion 182 of bore 160. Stud 180 projects from the bore to an extent permitting it to be contacted by end 184 of lever 150 when the latter is rotated in a counterclockwise direction which causes a projection 186 on the stud to engage the ball check valve 164 to move the latter 01f its seat. Unseating valve 164 permits manifold vacuum to enter passage 17-6 7 to shift the cold enrichment device 96 to its normal operating position as described, supra. Fuel metering device 30 includes an upper diaphrag casing member 190 having a threaded boss 192 formed thereon. A connector plug indicated generally at 194 is threadablym'ountedin boss 192 and has- vacuum conduits 196 and 198 threadably mounted thereon. Conduits 196 and 198 respectively communicate venturi vacuum and an idle metering vacuum to the upper side of diaphragm 92for the purpose described in Serial No. 608,- 797 Olson, filed September 10, 1956.

Plug 194 has a boss 200 formed thereon and to which a conduit 202 is suitably secured. Conduit 202 communicates with the plenum chamber 16, as'best seen in Figure l, and is adapted to superimpose a manifold vacuumforce on the upper side of diaphragm 92.

The upper casing wall 34 of the metering casing has an opening 206 formed therein which threadably receives plug 208. Connected to plug 208 is a conduit 210 alsoconnected with the plenum chamber 16 to transmit manifold vacuum to the fuel reservoir or float bowl chamber 44. Inasmuch as casing wall 51 is perforated to communicate reservoir 44with the metering chamber 48, manifold vacuum acts'on the top of spill sleeve 82 tending to lift the latter to bypass additional fuel. At the same time manifold vacuum leaks around rod 116 to act on the bottom of diaphragm 92 tending to move the latter downwardly against the vacuum forces acting ontop of thediaphragm. By calibrating atmospheric bleeds and selecting proper orifice sizes in the vacuum conduits 202 and'210 the combined manifold vacuum forces acting on sleeve 82 and the underside of diaphragm 92 willbalance the manifold vacuum force acting on top of the diaphragm under normal operating conditions. To illustrate, it hasbeen found that manifold vacuum of .05-.07 inch of water might be acting on the top of diaphragm 92, whereas the vacuum in chambers 44 and 48 might approximate 7 inches of Water. However, since the area of the top of sleeve 82 is so much less than that of the diaphragm 92 and further in vie-w of the atmospheric bleed 212 reducing the vacutun acting on the underside of the diaphragm the resultant manifold vacuum forces acting on the diaphragm and metering valve 54 may be substantially balanced.

Conduit 202 has interposed therein an accumulator 216 and an orifice 218, the latter being disposed between the accumulator and the plenum chamber 1 6. The accumulator 216 may be of any construction desired ineluding an enlarged chamber within which manifold vacuum may accumulate. In the event the vehicle operator suddenly depresses the accelerator pedal in order toaccelerate the engine, it is apparent that the vacuum in plenum chamber 16 will momentarily decrease which phragm 92. Accordingly, diaphragm 92 will be moved upwardly increasing the quantity of fuel delivered from metering valve 54 to conduit 28. After a given time interval the manifold vacuum forces will again be equalized even under continued accelerating conditions so that the control of the metering diaphragm 92 will again be controlled by the venturi vacuum in conduit 196.

It is apparent that by selecting an appropriate size for orifice 218 the interval through which the accelerating influence of manifold vacuum acts on the diaphragm 92 may be varied, i.e., a relatively large orifice making the acceleration enrichment of short duration whereas a relatively small orifice will lengthen the duration of the acceleration charge. It is apparent that the acceleration cycle as just described will be repeated each time the accelerator is depressed sufliciently to create a significant vacuum differential between the conduits 202 and 210.

While the accumulator 216 is desirable in accentuating the pressure differential effect described, it would be possible, at least in principle, to eliminate the accumulator through the use of a smaller orifice 218.

Various structural modifications are possible within the intended scope of the present invention.

I claim:

1. A fuel injection system for an internal combustion engine comprising an induction passage for supplying air to the cylinders of the engine, a throttle for controlling the flow of air through said passage, a source of fuel under pressure, conduits respectively communicating each cylinder with said fuel source, valve means disposed intermediate said fuel source and said conduits for controlling the quantity of fuel delivered to the cylinders, a member responsive to the mass of air flowing through said induction passage for controlling said valve, means for applying substantially equal and opposite engine load responsive forces to said valve, and means for creating a pressure differential between said forces during acceleration of said engine whereby the force unbalance shifts said valve to increase the quantity of fuel delivered to said cylinders.

2. A fuel injection system for an internal combustion engine comprising an induction passage for supplying air to the cylinders of the engine, a throttle for controlling the flow of air through said passage, a source of fuel under pressure, conduits respectively communicating each cylinder with said fuel source, valve means disposed intermediate said fuel source and said conduits for controlling the quantity of fuel delivered to the cylinders, a member responsive to the mass of air flowing through said induction passage for controlling said valve, means causing substantially equal and opposite manifold vacuum forces to act on said metering valve during normal engine operation, and means causing a delay in the decrease in one of said forces when manifold vacuum decreases during engine accelerated whereby the fuel-air ratio is momentarily enriched.

3. A fuel injection system for an internal combustion engine comprising an intake passage for supplying air to the cylinder of the engine, a throttle for controlling the flow of air through said passage, a venturi in said intake passage anterior of the throttle, a fuel reservoir, conduits respectively communicating each cylinder with said reservoir, a pump in said reservoir supplying fuel under pressure to said conduits, a valve disposed intermediate said pump and said conduits for controlling the quantity of fuel delivered to the cylinders, said valve being in communication with the reservoir, a diaphragm connected to the valve, a conduit communicating the diaphragm with the venturi for actuating said valve in accordance with the mass of air flowing through the venturi, a pair of conduits respectively communicating the reservoir and diaphragm with the intake passage posteriorly of the throttle causing substantially equal and opposite manifold vacuum forces to act on the valve during normal operating conditions, and means causing a delay in the decrease in one of said forces when manifold vacuum decreases during engine acceleration resulting in a momentary enrichment of the fuel-air ratio.

4. A fuel injection system as set forth in claim 3 in which said delaying means comprises an orifice in the conduit connecting said diaphragm with said intake passage posteriorly of the throttle valve.

5. A fuel injection system as set forth in claim 3 in which said delaying means comprises a vacuum accumulator and an orifice in the conduit connecting said diaphragm with said intake passage posteriorly of the throttle valve.

6. A fuel injection system as set forth in claim 5 in which said vacuum accumulator is disposed between said diaphragm and said orifice.

7. A fuel injection system for an internal combustion engine comprising an intake passage for supplying air to the cylinder of the engine, a throttle for controlling the flow of air through said passage, a venturi in said intake passage anterior of the throttle, a fuel reservoir, conduits respectively communicating each cylinder with said reservoir, an engine speed responsive pump in said reservoir supplying fuel under pressure to said conduits, a valve disposed intermediate said pump and said conduits for controlling the quantity of fuel delivered to the cylinders, said valve being in communication with the reservoir, a diaphragm connected to the valve, a passage communicating the diaphragm with the venturi for actuating said valve in accordance with the mass of air flowing through the venturi, a pair of conduits respectively communicating the reservoir and diaphragm with the intake passage posteriorly of the throttle, manifold vacuum in the reservoir conduit acting directly on said valve and on one side of said diaphragm, manifold vacuum in the diaphragm conduit acting on the other side of said diaphragm to normally balance the manifold vacuum forces tending to move said valve, and means causing a delay -in the decrease in one of said conduits when manifold Vacuum decreases during engine acceleration resulting in a momentary enrichment of the fuel-air ratio.

8. A fuel injection system as defined in claim 7 in which said delaying means comprises a vacuum accumulator and an orifice in the conduit connecting said diaphragm with said intake passage posteriorly of the throttle valve.

No references cited.

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