US2878798A - Split engine - Google Patents

Description

5 Sheets-Sheet 1 Filed May 29, 1958 A TTOPNEY March 24, 1959 J. DoLzA ET AL SPLIT ENGINE 3 Sheets-Sheet 2 Filed May 29, 1958 ATTP/VEY March 24, 1959 J. DoLzA ET AL 2,878,798

SPLIT ENGINE Filed May 29,;1958 v s sheetsheet 3 INVENTORS ATTORNEY SPLIT ENGDIE John Dolza, Fenton, and William H. Kolbe, Huntington Woods, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 29, 1958, Serial No. 739,649

13 Claims. (Cl. 123-127) The present invention relates to a mechanism for providing split operation of an internal combustion engine. By split operation it is meant that the engine may be operated on less than all of the engines cylinders for the purpose of making engine operation more economical.

Engine operation is more economical if each cylinder of the engine is run under relatively high loads. However, under most vehicle operating conditions the engine is operating under relatively light loads resulting in uneconomical fuel consumption. Accordingly, it is desired to operate the engine `on say half of the cylinders during normal or light load operation with the remaining cylinders being brought into operation only after the load on the engine exceeds a given value. In this way it is possible to increase the load on each of the active cylinders and in that way achieving greater overall operating economies for the engine.

It is an inherent characteristic of an internal combustion engine to be most efficient under high load conditions. This is attributable to the quantity of air fed to the cylinders. Maximum air is supplied to the cylinders 'when the throttle is open, indicative of high load, therefore, more air may be compressed in turn increasing the compression pressure. Since engine efficiency increases with compression pressure and compression pressure increases with cylinder load, the desirability of split or part cylinder engine operation as a means for maintaining high cylinder loads becomes apparent.

In the present device a fuel injection system is employed in which a pair of air intakes is provided and each of which supplies air to one-half of the engines cylinders. One of said air intakes is active at all times to supply air whereas the other intake is normally inactive being rendered active only after the engine load exceeds a given value. A fuel metering mechanism is provided whereby fuel is normally supplied to the active cylinder nozzles and fuel flow blocked to the nozzles feeding the inactive cylinders. A servo mechanism is provided for controlling throttle actuation in accordance with accelerator pedal position as well as engine load whereby the throttle position is always properly adjusted in accordance with engine capacity.

To maintain high engine operating efficiency during split engine operation, in addition to -cutting oif fuel ow to the inactive cylinder nozzles, the throttle valve in the inactive air intake passage is maintained in a fully opened position to reduce pumping losses. Means is provided for closing the inactive throttle whenever the transition is made from part to full engine operation.

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

In the drawings:

Figs. la and lb are diagrammatic representations of a fuel system embodying the present invention; and

Figures 2-4 are enlarged detail views of the active throttle adjusting mechanism.

A pair of air intake casings and 12 are adapted respectively to supply air to four of the eight cylinders of tes Patf't r'ice g a V-type engine with which the present device has been illustrated. lt is apparent, of course, that the application of the invention is in no way limited to an eight cylinder engine. The air intake casings include air induction passages 14 and 16 having venturis 18 and 20 formed therein. Throttle valves 22 and 24 respectively control the flow of air through induction passages 14 and 16. As will subsequently be considered in greater detail, induction passage 16 is operative at all times when the' engine is operating to supply air to the engine for com.- bustion purposes. For this reason air intake passage 16 is characterized as the active intake. Air intakel14, on the other hand, is normally inactive to supply air for combustion purposes and is therefore characterizedtals the inactive intake.

Intake passages 14 and 16 respectively communicate with manifolds 26 and 28 which in turn supplyq air'to individual cylinder mixture passages 30 and 32. In the illustrative embodiment, passages 30 are adapted to supply four inactive cylinders 34 while passages 32 supply four active cylinders 36.

Considering first the active air intake 12,and its operation, it is to be noted that each of the individual cylinder mixture passages 32 includes a fuel nozzle 38 disposed proximate the associated engine cylinder 36 and is adapted to supply fuel thereinto when the cylinder irrtake valve 40 is opened. Fuel in metered quantities is supplied to each of the nozzles 38 by a metering control device indicated generally at 42 and which device is responsive to the mass or quantity of air flow through active air intake 12. The fuel metering operation for supplying fuel to the active cylinders of the engine is substantially the same as that described in the fuel injection application, Serial No. 608,853 Dolza, tiled September 10, 1956, now Patent No. 2,843,098. This system will be described in the Ipresent instance only insofar as is necessary to an understanding of the split engine operation only the latter which is the subject matter of the present invention.

Fuel metering mechanism 42 includes a metering valve 44 supplied with fuel under pressure from an inlet con'- duit 46 which is, in turn, supplied from a pump 48. As may be more fully understood in the aforenoted Dolza application, metering valve 44 is adapted to control the quantity of fuel supplied to the nozzle fuel conduits 50.

by controlling the quantity of fuel which is bypassed back to a sump 52 through a yconduit 54. The control of metering valve 44 is, in general, regulated by a metering diaphragm 56. Diaphragm 56 has a control rod 58 centrally fixed thereto and Iwhich rod is articulated to a lever 60 one end of which engages the metering valve. An adjustable fulcrum 62 is provided and engages lever 60 between rod 58 and valve 44. In this way movement of diaphragm 56 will cause lever 60 to pivot around fulcrum 62 and in turn vary the axial position of the metering valve. This in turn varies the quantity of fuel bypassed to sump 52 thereby determining the quantity of fuel supplied to the engine.

An annular chamber 64 is formed in air intake casing 12 and communicates at its inner end with the throat of venturi 20. Annular chamber 64 is communicated with diaphragm chamber 66 through a conduit 68.. Thus as the quantity of air flow through intake passage 16 increases, a vacuum force is created in chamber 64 which is proportional to the square of such ilow. In operation, as the air flow through air intake passage 16 increases the vacuum force in diaphragm chamber 66 likewise -increases raising diaphragm 56, control rod 58, causing lever 60 to pivot in a clockwise direction about the fulcrum 62 depressing or lowering the metering valve 44 and in so doing reducing the quantity of fuel bypassed to 3 sump 52 thereby increasing the quantity of fuel supplied to the fuel nozzles.

It is to be noted that the fuel metering valve 44 is formed as a part kof a nozzle fuel distributing device which includes an upper casing 70 adapted to supply fuel to the four active nozzles 38, an intermediate casing 72 through ywhich fuel is supplied to the metering valve and a lower casing 74 from which fuel is supplied to the four inactive nozzles 76.

The ow of fuel to inactive nozzles 76 is controlled by a valve 80 actuated by a solenoid 82. Under conditions in which split or part cylinder engine operation is desired, solenoid 82 is deenergized in which event spring 8 4 moves valve 80 to block fuel flow from passage 86 which otherwise supplies fuel to the inactive nozzle conduits 88. As will subsequently be considered in greater detail, when full engine operation is'desired solenoid v82 is energized opening valve 80 permitting fuel to be supplied in equal 4quantities to -both the active and inactive P93195- v.While induction air is drawn in through both air induction passages 14 and 176, fuel metering, whether during split or full engine operation, is controlled by the air flow through the active air intake 16. Venturi 20 in active air intake 16, as already noted, contains the annular vacuum chamber or piezometer ring 64 and is of such a size that one-half of the engine operation will produce the same vacuum signal on this venturi as total engine air ow would produce on the large cross section venturi used in the aforenoted Dolza application. This is possible inasmuch as the subject venturi may be of a considerably smaller Vsize since it is only required to supply a portion of the air requirements of the engine under high load operating conditions when the balance of the required air is supplied by the other air intake passage 14.

Since venturi vacuum in chamber 64 is proportional to the nozzle pressure drop and further since all nozzles are connected in parallel, any number of nozzles may be connected to the fuel control distribution device 70-74 and the metering valve 44 will automatically adjust itself to provide the requisite fuel flow to the nozzles. Thus the switching from four to eight nozzle operation by energizing solenoid V82, is accomplished smoothly with only a repositioning of the metering valve spill plunger.

Therefore, since venturi depression is proportional to the nozzle pressure drop, as just described, and with equal restriction in each air induction passage by virtue of the identical sizes of the respective venturis 18 and 20, a.

the venturi fuel metering vacuum signal may be taken off from the active yair meter only under all operating conditions.

A coasting Afuel shut-off device is shown generally at 90 and functions in a manner substantially the same as that shown and described in the aforenoted copending Dolza application. The coasting fuel shut-off device 90 is connected to fuel supply passage 46 and fuel bypass passage 54 through branch conduits 92 and 94 respectively. Under normal operating conditions, valve member 96 is biased by a spring 98 blocking fuel ow through device 90. A diaphragm 100 is fixed to valve 96 and communicates with induction passage 16 by a conduit 102 terminating in passage 104 which communicates with passage 16 anteriorly and posteriorly of the throttle valve24.

Under normal operating conditions any vacuum force acting on diaphragm 100 will be too weak to overcome `the force of spring 9S. However, when throttle valve 24 is closed under coasting conditions, a portion 106 of the valve is adapted to block the anterior branch of passage o f eouduit 104 causing manifold vacuum to be transmitted through posterior branch of conduit 104 to conduit 1021 Manifold vacuum will then lift diaphragm 100 against the force of spring 98 causing fuel to be bypassed 4 from the supply branch conduit 92 to the bypass conduit 94 thereby interrupting fuel flow to the fuel nozzles. Upon reopening of throttle 24, the vacuum force acting on diaphragm will again be reduced sufficiently to permit spring 98 to close valve 96 restoring the normal fuel ow to the fuel metering valve 44.

Referring particularly to Figure la, the operation and control of throttle valves 22 and 24 will now be described. Active and inactive throttles 24 and 22 are operatively interconnected by a linkage arrangement which includes arms 108 and 110 and connected by a link 112. Arm 110 is fixed to active throttle shaft 114 for rotation therewith. Arm 108, on the other hand, is loosely mounted on the inactive throttle shaft 116 permitting relative movement between valve 22 and arm 108.

It is desired to maintain the inactive throttle 22 in an open position to prevent pumping losses during split engine operation, therefore, it is necessary to provide a lost motion connection between the active and inactive throttle which includes the loosely mounted arm 108. A second lever 118 is xed to inactive throttle shaft 116 and lincludes a tab 120 adapted to engage arm 108 under certain conditions. A solenoid armature 122 is tixed to or formed integrally with arm 118 and cooperates with solenoid coil 124 such that when the solenoid is energized the throttle valve 22 will be moved to a full open position, as shown, against the force of a throttle closing spring 126. Under these conditions, it is apparent that the active throttle 24 Vmay be actuated without having any eiect on the operation of the inactive throttle 22. Through a lead 130, contact 132, movable contact 134 and lead 136, solenoid 122- 124 is connected in the ignition circuit such that when the ignition is on and contacts 132 and 134 in engagement the solenoid will be energized opening throttle 22. Where, on the other hand, full engine operation is desired, means is provided for deenergizing the throttle solenoid under which condition spring 126 will rotate armature 122 and hence throttle valve 22 in a closing direction in which tab 120 of arm 118 engages arm 108 whereby actuation of the throttles 22 and 24 will be coordinated by a mechanism lnow to be described.

In general, the active throttle 24 is controlled in accordance with the position of an accelerator pedal 140. However, the precise positioning of the active throttle is modified by a regulating mechanism indicated generally at 142. Mechanism 142 includes a servo piston 144 having a rod 146 articulated through a link 148 to a bell crank lever 150. Bell crank lever 150 is mounted on an adjustable pivot 152 and is articulated at its other end to active throttle lever 110 through link 154. The adjustable pivot 152 provides the articulated connection between bell crank lever 150 and a lever 156 pivotally mounted upon a fixed bracket 158. Lever 156 is articulated to the accelerator pedal by a link 160. As thus far described, initial opening movement of the accelerator pedal 140 will cause the lever 156 to be rotated in a counterclockwse direction which in turn causes Athe bell crank to be moved to the right imparting a slight, eg. l to 2 degree, opening of the active throttle 24.

The transition from half or split engine operationto full operation must be accomplished smoothly without any load or speed change. Therefore, it was decided that such shifting be accomplished at constant load or engine torque. Torque is a function of manifold vacuum. Further, on an average throughout the engines speed range the torque at one-half engine manifold vacuum close to wide open throttle was found to be roughly the same as the torque at full engine operation with the throttle approaching the closed position. Accordingly, the basis for automatic throttle operation was established. In other words, during half engine operation when the engine had been accelerated to the point where the active throttle 24 is substantially wide open, the conditions for transition to full engine operation are established. As a part of this transition, it is necessary to provide means for returning the active throttle to a generally closed position at the same time as the inactive throttle 22 is moved to a closed position, supra.

Returning now to pressure regulator mechanism 142, a lever 162 is pivotally mounted intermediate its ends upon a fulcrum 164 whose position is determined by a pair `of bellows 166 and 168. Bellows 166 is evacuated and therefore is an aneroid, whereas bellows 168 is connected through a conduit 170 with the active induction passage posteriorly of the throttle 24 so as to subject the latter bellows to manifold vacuum and hence engine load. The bellows assembly, therefore, always relates the system to -a theoretically complete Vacuum.

The upper end of lever 162 is moved by a spring 172 into engagement with a rotatable cam member 174. Cam 174 includes an arm 176 articulated through a link 178 with the upper end of accelerater pedal controlled lever 156. The lower end of lever 162 is connected with a servo control valve 182 which, as the lever is moved, causes engine oil pressure to be admitted to or exhausted from servo cylinder 184 whereby the servo piston will move the bell crank lever 150 and hence alter the position of the active throttle 24. More specifically, as the t accelerator pedal 140 is moved in a counterclockwise or throttle opening direction, cam 174 is caused to rotate in a counterclockwise direction presenting a lower point of the cam surface to lever 162. This causes spring 172 to rotate lever 162 in a counterclockwise direction about fulcrum 164. This movement of lever 162 causes servo control valve 182 to move to the right whereby oil under pressure from inlet 186 is adapted to ow through the valve through port 188 in valve casing 190 and hence to port 192 in servo cylinder 184. Under this condition oil under pressure will move the servo piston 144 to the left causing a clockwise pivoting of the bell crank lever 150 about its pivot 152. This action in turn opens the throttle valve 24.

It becomes apparent that the yopening movement of the throttle 24 will cause the manifold vacuum in conduit 170 to drop. In this case a spring 194 within bellows 168 expands the bellows to the left imposing a similar leftward movement on the servo control valve 182. This valve movement blocks the llow `of oil to servo piston 144 and thereby preventing further servo actuation of throttle valve 24 until the operator once again makes an adjustment in the accelerator pedal position.

In similar fashion a closing movement of accelerator pedal 140 would cause the fluid acting on servo piston 144 to be exhausted and returned to sump through conduit 196 whereby spring 198 biases servo piston 144 in a rightward direction to close throttle 24 until manifold vacuum had once again established a balanced condition.

The means whereby the transition is made from split or half engine operation to full engine operation will now be considered. The transition is, in general, controlled by an accelerator pedal controlled switch mechanism indicated generally at 200. As already noted, switch mechanism 200 includes a contact 132 for controlling the inactive throttle solenoid 3122-124, as well as movable contact 134 pivoted at 202. Movable contact 202 is connected to a rod 204 which terminates in a piston like member 206 slidably mounted in a sleeve 208 formed in the switch casing 210. A plunger 212 is also slidably mounted within sleeve 208 and provides a seat for one end of a spring 214 the other end of which biases against the piston like member 206. Spring 214 `urges rod 204 and plunger 212 apart. An additional spring 216 mounted upon a seat 218 within the switch casing biases the movable contact 134 to the right or clockwise direction causing movable contact 134 to engage with inactive throttle solenoid contact 132 to energize the latter solenoid as already described. This then is the condition of the switch mechanism 200 during split engine operation.

A portion 220 of -accelerator pedal control lever 156extends upwardly therefrom and adjustably supports a stud member 222 axially aligned with switch plunger 212. Under low power operating conditions and until the accelerator pedal is moved to a predetermined position, e.g., one-third open, stud 222 and plunger 212 will be out of operative engagement. However, when the accelerator pedal exceeds the predetermined open position, plunger 212 will be engaged by stud 222 to compress spring 214 until the force of the spring overcomes the force of spring 216 shifting movable contact 134 out of engagement with contact 132 and into engagement with another contact 224. By opening contact 132 the inactive throttle solenoid 122-124 is deenergized. Spring 126 will then cause throttle 22 to be rotated in la closed direction until the tab on lever 118 engages with the active throttle controlled arm 108.

At the same time, the closing of contact 224 first energizes the fuel solenoid 82 through lead 226 causing metered fuel to flow to the four previously inactive nozzles 76. Secondly, the closing of contact 224 energizes another solenoid 228 through lead 230. Solenoid 228 includes a rod-armature 232 articulated to a lever 234. Lever 234 is concentrically fixed to a disc member 238.

A rod 240 is eccentrically supported at one end to disc member 238 and at its other end to cam 174. Accelerator pedal controlled lever 176 is fixed to cam 174 through pin 240 whereby the cam may be rotated to adjust its position with respect to lever 162, supra.

As already noted, in order to make transitions between split and full engine operation it is necessary to reschedule the position of active throttle 24. In other words, during four cylinder operation the active throttle must be more open than during eight cylinder operation in order to properly sustain engine operation. Solenoid 228 and associated mechanism are provided for rescheduling the active throttle position as follows.

During four or split cylinder operation solenoid 228 is deenergized whereby the parts are in the positions shown in Figures la and 2. When accelerator pedal is depressed beyond the predetermined amount, e.g. onethird open, switch 200 energizes solenoid 228. This causes counterclockwise rotation of lever 234 and member 238. This movement of member 238 causes similar movement of rod 240 pivoting cam 174 and lever 176 counterclockwise about the pivotal connection 177 between levers 176 and 17 8. As seen by comparing Figures 3 and 4, this relatively rotates cam 174 with respect to lever 162 and presents a lower cam surface thereto. AC- cordingly, spring 172 will move lever 162 in a counterclockwise direction causing the right side of servo piston to be exhausted and imparting a closing movement to active throttle 24.

Thus switch 200 in deenergizing solenoid 122-124 and energizing solenoid 228 closes and operatively connects throttles 22 and 24 whereby the throttles are positioned for full engine operation. From this point on and with accelerator pedal movement in an opening direction, the opening movement of throttles 22 and 24 will be synchronized and controlled by the accelerator pedal position in conjunction with pressure regulating mechanism 142 in the same manner as the latter controlled the operation of the active throttle when .functioning alone.

As described in copending application Serial No. 608,797, Olson, filed September lO, 1956, during idle and oi-idle operation of the active throttle 24 the air flow through the active venturi 20 is relatively low as a consequence of which the metering signal in piezometer ring or chamber 64 is likewise frequently too low to provide satisfactory control of metering diaphragm 56.

In the present system it is not possible to utilize the off idle enrichment of the type disclosed in the aforenoted Olson application and due to the large active throttle opening on four or part cylinder operation andthe resultant low Amanifold vacuum `available for vsuch supplemental metering enrichment. To supplement the meteringcontrol force under these conditions in the present system, a transient control valve indicated generally at 244 is provided. Valve 244 includes a Vdiaphragm 246 peripherally clamped between a-pair of casing members '248 and 250. A boss 252 is formed in casing 250 and includes apassage 254 which communicates with a conduit 256 connected with `the metering vacuum conduit 68. A second conduit 258 communicates with the chamber 260 defined by casing 250 and diaphragm 246 and dclivers manifold vacuum thereto by communicating with induction passage 16 posteriorly of throttle 24.

A pair of passages 262 and 264 containing a calibrated restriction are respectively formed in casings 248 and 250 and coact `to provide a bypass around the diaphragm 246 which interconnects chambers 260 and A266. A valve member 268 is vcentrally fixed `to diaphragm 246 and is normally seated upon boss 252 by spring 270 to prevent interconnection between manifold vacuum and the venturi vacuum respectively existing in conduits 258 and 256. Under engine idling conditions a relatively high manifold vacuum will be admitted to both chambers 260 and 266 through bypass passages 262 and 264. During idling, the manifold vacuum is the same in chambers 260 and 266. As soon as the throttle is opened, the vacuum drops in chamber 260, however, the calibrated restriction in passages 262-264 momentarily maintains the vacuum in chamber 266 at a higher value than that in chamber 260. This higher vacuum acting on diaphragm 246 0pposes spring 270 and lifts valve 268 allowing manifold vacuum to communicate with passage 254 and reinforce the venturi metering signal in conduit 256. The manifold vacuum differential across diaphragm 246 and the length of time valve 268 is open is dependent upon the vspring force 270 and the size of the calibrated restriction in lines 262-264 respectively.

In ithis way, valve 268 will remain open during the transition or opening movement of the throttle from an idle or olf-idle position to a more fully open position which permits a smooth tip-in and eliminates a fall-off in power due to a leaning of the charge which would otherwise occur.

The mechanism shown generally at 274 is provided to mechanically hold the valve 268 closed when the throttle is closed. Coasting then braking to a stop will cause a large enough change in manifold vacuum to actuate device `244 and stall the engine by virtue of over enrichment. Alsoymanifold vacuum variations at idle are great enough to stall the engine for the same reason. `Mechanism 274 includes a lever 276 pivotally supported upon bracket 27 3. The free end of lever 276 extends downwardly and terminates in axial alignment with the stud 222 of accelerator pedal controlled lever 156. A stud 279 is dependingly articulated from lever 276 and is surrounded by a spring member 230 seated upon casing 248 and urging the lever in a clockwise direction. Thus, as the accelerator pedal approaches a closed position it will engage lever 276 moving stud 279 into engagement with diaphragm valve 268 to retain the latter in a seated condition.

We claim:

1. A charge forming device for an internal combustion engine comprising a first air intake for supplying air to certain of the engine cylinders, a second air intake for supplying air to the remainder of said engine cylinc en throttle valves in each of said air intake passages for controlling the quantity of air ow therethrough, nozzles for supplying fuel to the individual cylinders of the engine, a fuel metering mechanism for supplying fuel to said nozzles in accordance with the mass of air flow through one of said air intake passages, means for cutting off the supply of fuel to the nozzles associated With one of said air intake passages, means for fully opening the throttle valve in the intake passage when the assoeiated fuel nozzles are not being supplied with fuel, an accelerator pedal adapted to control the operation of said throttle valves, means for modifying the accelerator control of said throttle valves in accordance with engine load, and means responsive to a predetermined opening of said accelerator pedal for `restoring fuel ow to all fuel nozzles and for moving both of said throttles toward a closed position when the transition is made from split to full engine operation.

2. A charge forming device for an internal combustion engine comprising a first air intake for supplying air to certain of the engine cylinders, a second air intake for supplying air to the remainder of said engine cylinders, throttle valves in each of said air intake passages for controlling the quantity of air ow therethrough, nozzles for supplying fuel to the individual cylinders of the engine,

va fuel metering mechanism and distributor for supplying fuel to said nozzles in accordance with the mass of air .ow through one of said air intake passages, said distributor adapted to continuously supply fuel to the nozzles associated with one of said air intakes, said distributor including means for cutting o the supply of fuel to the nozzles associated with the other of said air intake passages, means for fully opening the throttle valve in the intake passage when the associated fuel nozzles are not being supplied with fuel, an accelerator pedal adapted to control the operation of said throttle valves, means for modifying the accelerator control of said throttle valves in accordance with engine load, and means responsive to a predetermined opening of said accelerator pedal for restoring ,fuel flow to all fuel nozzles and for moving both of said throttles toward a closed position when the transition is made from split to full engine operation.

3. A charge forming device for an internal combustion engine comprising a first air intake for supplying air to certain of the engine cylinders, a second air intake for supplying air to the remainder of said engine cylinders, throttle valves in each of said air intake passages for controlling the quantity of air flow therethrough, nozzles for supplying fuel to the individual cylinders of the engine, a fuel metering mechanism and distributor for supplying fuel to said nozzles in accordance with the mass of air ow through one of said air intake passages, said distributor adapted to continuously supply fuel to the nozzles associated with said first air intake, said distributor including means for cutting olf the supply of fuel to the nozzles associated with the second air intake passages, means for fully opening the second air intake throttle valve when the associated fuel nozzles therewith are not being supplied with fuel, an accelerator pedal adapted to control the operation of said throttle valves, means for modifying the accelerator control of said throttle valves in accordance with engine load, and means responsive to a predetermined opening of said accelerator pedal for lrestoring fuel llow to all fuel nozzles and for moving both of said throttles toward a closed position when the transition is made from split to full engine operation.

4. A charge forming device for an internal combustion engine comprising a first air intake for supplying air to certain of the engine cylinders, a second air intake for supplying air to the remainder of said engine cylinders, throttle valves in each of said air intake passages for controlling the quantity of air ow therethrough, nozzles for supplying fuel to the individual cylinders of the engine, a fuel metering mechanism for supplying fuel to said nozzles in accordance with the mass of air flow through one of said air intake passages, valve means for cutting olf the supply of fuel to the nozzles associated with one of said air intake passages, a first solenoid for controlling the fuel cut-oft valve, a second solenoid for fully opening the throttle valve in the intake passage when the associated fuel nozzles are not being supplied with fuel, an accelerator pedal adapted to control the operation o f said throttle valves, means for modifying the accelerator control of Asaid throttle valves in accordance with engine v t 9 load, a third solenoid for actuating the accelerator control modifying means to move said throttles in a closing direction, and switch means responsive to -a predetermined opening of said accelerator pedal to control actua'- tion of said solenoids for restoring fuel ow to all fuel nozzles and for moving both of said throttles towarda closed position when the transition is made from split to full engine operation.

5. A charge forming device for an internal combustion engine comprising a first air induction passage, a plurality of individual cylinder intake passages leading from said intake passage and communicating with certain of the cylinders of the engine, a second air induction passage, a plurality of individual cylinder intake passages leading from said second induction passage and communicating with the remaining cylinders of said engine, a fuel nozzle in each of said individual cylinder intake passages for supplying fuel to the associated cylinder, a throttle valve in each of said induction passages for controlling the quantity of air iiow therethrough, fuel metering means for supplying fuel to said nozzles in accordance with the mass of air ow through one of said induction passages, means for synchronizing the operation of said throttle valves, an accelerator pedal adapted to control the operation of said throttle valves, engine load responsive means for modifying the operation of said ,throttle valves by said accelerator pedal, and accelerator pedal controlled means operable under light engine load conditions for simultaneously fully opening one of said throttle valves and cutting off the flow of fuel to the nozzles in the individual cylinder intake passages associated with said fully opened throttle.

6. A charge forming device as set forth in claim in which the throttle synchronizing means includes a lost motion mechanism adapted to permit only one of said throttles to be actuated to control the engine under low load conditions.

7. A charge forming device as set forth in claim 5 in which the throttle synchronizing means comprises a first lever fixed for rotation with one of said throttle valves, a second lever connected for relative rotation with the other throttle valve, a link articulated between said rst and second levers, a third lever xed for rotation with the other throttle valve, tab means on said third lever, spring means biasing the third lever in a throttle closing direction causing the tab means to engage said second lever, means for fully opening the other throttle valve against the force of said spring means, and an accelerator pedal controlled lever articulated to the first lever to open said one throttle as the pedal is depressed.

8. A charge forming device for an internal combustion engine comprising a first air induction passage, a plurality of individual cylinder intake passages leading from said intake passage and communicating with onehalf of the cylinders of the engine, a second air induction passage, a plurality of individual cylinder intake passages leading from said second induction passage and communicating with the other half of the cylinders of said engine, a fuel nozzle in each of said individual cylinder intake passages for supplying fuel to the associated cylinder, a throttle valve in each of said induction passages for controlling the quantity of air flow therethrough, fuel metering means for supplying fuel to said nozzles in accordance with the mass of air ow through one of said induction passages, an accelerator pedal, means adapted to control the operation of said throttle valves in accordance with accelerator pedal position, said throttle valve controlling means comprising a linkage device interconnecting said throttle valves, a servo mechanism operatively connected to said linkage device, a valve element controlling iiuid for actuating the servo, a pivoted lever articulated to said valve element, a rotatable cam member articulated for movementI with the accelerator pedal, said cam member adapted to coact with the pivoted lever permitting the servo to move at i 4 "y least one of said throttle valves in an openiiig direction as ltheac'z'celerator pedal is depressed, and engine load responsive means for modifying the actuation 'of said valve element to limit throttle 'valve movement.

9. A chargeforming device for an internal combustion engine Vcomprising a rst air induction passage, .a plurality of individual cylinder intake passages leading from said intake passage and communicating with onehalf of the 'cylinders of the engine, a second air indue tion passage, a plurality of individual cylinder intake passages leading from said second induction passage and communicating with the other half of the cylinders of said engine, a fuel nozzle in each of said individual cylinder intake passages for supplying fuel to the associated cylinder, a throttle valve in each of said induction passages for controlling the quantity of air iiow therethrough, fuel metering means for supplying fuel to said nozzles in accordance with the mass of air ow through one of said induction passages, an accelerator pedal, means adapted to control the operation of said throttle valves in accordance with accelerator pedal position, said throttle valve controlling means comprising a linkage device interconnecting said throttle valves, a servo mechanism operatively connected to said linkage device, a valve element controlling liuid for actuating the servo, a pivoted lever articulated to said valve element, a rotatable cam member articulated for movement with the accelerator pedal, said cam member adapted to coact with the pivoted lever permitting the servo to move at least one of said throttle valves in an opening direction as the accelerator pedal is depressed, and engine load responsive means for modifying the actuation of said valve element to limit throttle valve movement, and an accelerator controlled means operable under light engine load condition for simultaneously fully opening one of said throttle valves and cutting off the ow of fuel to the nozzles in the individual cylinder intake passages associated with said fully opened throttle.

10. A charge forming device as set forth in claim 9 in which said accelerator controlled means includes a device for shifting the rotative axis of said cam member to increase the degree of opening the throttle not already fully opened.

1l. A charge forming device as set forth in claim 8 in which said throttle valve controlling means includes a shaft fixed for rotation with the cam member, a rotat able member eccentrically supporting said cam shaft to permit relative rotation between said shaft and the member, means articulating said shaft to the accelerator pedal, and means for rotating said rotatable member to shift said shaft axis.

12. A charge forming device as set forth in claim 1l in which the means adapted to control operation of the throttle valves includes a first solenoid device for fully opening one of said throttle valves, a second solenoid for cutting off the flow of fuel to the nozzles in the individual cylinder intake passages associated with the fully opened throttle, a third solenoid for actuating the rotatable member rotating means, and an accelerator pedal actuated switch for controlling the solenoids whereby the remaining throttle will be moved to a more open position when the other throttle is fully opened.

13. A charge forming device for an internal combustion engine comprising a first air induction passage, a plurality of individual cylinder intake passages leading from said intake passage and communicating with certain of the cylinders of the engine, a second air induction passage, a plurality of individual cylinder intake passages leading from said second induction passage and communicating with the remaining cylinders of said engine, a fuel nozzle in each of said individual cylinder intake passages for supplying fuel to the associated cylinder, a throttle valve in each of said induction passages for controlling the quantity of air ow therethrough,

A11 .fuel .metering means for supplying fuel to said nozzles `in accordance with the mass of air .How .through one of Said induction passages, ,means yfor synchronizing the operation of said thpttle Valves, yan accelerator'pedal adapted to control Athe operation of `said throttle valves, engine load responsive y means .for modifying the operation of said throttle valves by said accelerator pedal, and accelerator pedal controlled means operable under light engine load conditions for simultaneously `fully opening 4one of -Said throttle valves and cutting off the flow of fuel to the nozzles in the individual cylinder intake passages associated with said full)I opened throttle, and solenoid means operable by said vaccelerator pedal controlled means for moving said throttle valves in a closing direction when the accelerator Pedal is opened beyond a predetermined amount.

No references cited.

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