US2914051A - Signal modifier for fuel injection system - Google Patents

Description

Nov. 24, 1959 5 Sheets-Sheet 1 Filed May 9, 1957 aff? IN VEN TORS J/f? 90/ A Trop/wry Nov. 24, 1959 J. DoLzA ETAL 2,914,051

SIGNAL MODIFIER FOR FUEL INJECTION SYSTEM Filed May 9, 1957 3 Sheets-Sheet 2 'ff @y NUV- 24, 1959 J. DoLzA ErAL v2,914,051

SIGNAL MODIFIER FOR FUEL INJECTION SYSTEM Filed May 9, 1957 3 Sheets-Sheet 3 IN V EN TORS A TTOR/VEY SIGNAL MODIFIER FOR FUEL INJECTION SYSTEM John Dolza, Fenton, and William H. Kolbe, Huntington Woods, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May-9, 1957, Serial No. 658,091

6 Claims. (Cl. 12S- 119) The present invention relates to a fuel :injection system of the mass `air flow type as generally shown in copending application Serial No. 608,853 Dolza, filed September 10, 1956, now Patent No. 2,843,098. In particular, the present device represents an improvement over the earlier Dolza system in providing a novel cold enrichment mechanism. In lthe earlier Dolza system a solenoid mechanism was provided which retained the fuel metering valve in Ia maximum flow position for a timed interval to obtain an enriched starting mixture. Such control results in a step type enrichment which approximates but does not reflect the actual needs of the engine.

In the present system a device is provided whereby a modulated enrichment of the system is achieved and which enrichment is accurately determined by the needs of the engine during warm up. In the present device the modulated enrichment is achieved by providing a metering signal modifying valve which is controlled by temperature and air flow in such a wayas to vary the metering vacuum signal in inverse proportion to such temperature and air flow. t

In the present invention the signal modifier valve is mounted in the air intake or induction passage anteriorly of the venturi and is offset with respect to the induction passage so as to be responsive to the air ow therethrough and is further connected with a thermostatic element which tends to close said valve with a force inversely proportional to temperature. The present signal modifier valve is adapted to coact with the venturi so as to provide a fuel metering control force which is proportional to the quantity of air flowing through theventuri and the degree to which said valve is closed.

2,914,051 Patented Nov. 24, 1.959

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The details as well as other objects and advantages of the present invention are set forth in the description which follows.

In the drawings:

Figure 1 is a partially sectioned view of a fuel injection system embodying the subject invention;

Figures 2, 2a and 2b are enlarged views showing the subject invention in greater detail; and Y Figures 3 and 4 represent a modified form of the subject invention.

Except as will hereinafter be specifically pointed out, the present fuel injection system functions in the same manner as in the aforenoted copending Dolza application.

` Brieiiy, the fuel injection system includes an intake casing 10 having an air induction passage 12 formed therethrough. The induction passage 12 includes a tapered plug 13 disposed therein which coacts with the casing 10 to define an annular venturi 14. A throttle valve 16 is also disposed in the induction passage 12 posteriorly to venturi 14. The induction passage communicates with an air manifold or plenum chamber 18'from which the l air is supplied to the individual cylinders of the engine through intake passages 20. Fuel under pressure is supplied from a source 21 to a valve member indicated generally at 22 Where the fuel is metered through the action of a diaphragm .controlled Avlinkage mechanism24. .The

which communicate with the individual cylinder intake passages 20 and each of which conduits terminates in a nozzle member 28. In this way the fuel and air are adapted to be mixed just prior to their induction into the engine cylinders 30.

Metering valve control mechanism 24 includes a diaphragm 32 having a vacuum chamber 34 which com-v municates with venturi 14 through a conduit 36 and an annular open venturi chamber 38. The diaphragm 32 also includes another chamber 40 which is vented to the atmosphere through a conduit 42 within the induction passage 12 anteriorly of the venturi 14.

As already noted, in the earlier Dolza application a solenoid was provided for retaining the meteringfvalve 22 in a maximum fuel output position to provide cold starting enrichment. The solenoid type enrichment control represents an approximation of engine needs and which cold starting and running enrichment control is considerably refined by the mechanism now to be described.

The theory of the present device has been to provide a mechanism whereby the metering control force acting on diaphragm 32 is reinforced or supplemented in inverse proportion to engine air flow land temperature. In this way when the engine is coldest a maximum metering signal will be generated and will retain the metering valve 22 in its maximum fuel output position. The reinforcing of the metering signal will progressively diminish or be modulated as the engine warms and becomes capable of running on a leaner fuel-air mixture.

To this end, and as shown in Figures l and 2, a signal modifying valve 50 is disposed in an extended intake casing portion 52 upon which an air cleaner 54 is adapted to be mounted. As better seen in Figures 2a and 2b, the

`modifyingvalve 50 is mounted on a shaft 56 which is offset with respect to the intake passage so that the valve is unbalanced and hence 'responsive to air flow tending to open as such oW increases. In order, under cold starting conditions particularly, to supplement the metering control signal which is normally generated in venturi chamber 38 by air fiow therepast, it is necessary to maintain the valve 50 in a closed position. In this way manifold depression will create a high vacuum force posteriorly of the modifier valve 50 and in so doing increase the vacuum force in vacuum chamber 38.

T o maintain the modifier valve in a closed position and to open the same as the engine warms, a temperature responsive mechanism indicated generally at 58 is provided. The temperature responsive mechanism includes a bimetalliccoil e1ementv60 adapted to be anchored at one end 62 to the induction casing and fixed at its other end to the modifier valve shaft 56. Thermostatic coil 60 is so arranged that the force with which it retains the valve 50 in a closed position varies inversely with temperature.,

It is also desirable to make the modier valve 50 responsive to engine load which is manifested by the magnitude manifold vacuum. To this end, a vacuum piston 64 is mounted in a bore 66 formed in the casing 68 of the thermostatic mechanism 58. Piston 64 is suitably articulated to the modifier valve shaft 56 through a link 70 and a lever 72 fixed to the shaft. A conduit 74 is adapted to communicate manifold vacuum to the end of the vacuum piston 64 so as to urge the latter in a valve opening direction as manifold vacuum increases to indicate a decrease in engine load.

As thus far described the signal modifier valve is made responsive to three engine operating conditions, namely, engine temperature through bimetallic member 60, engine demand through the offset or unbalance construction of Valve 50 and engine load through vacuum piston 64.

If it should be desired to tailor the operation of the signal modifier valve for a particular type of stepped operation, it is possible to provide a passage 76 in the vacuum piston 64 which is adapted to bleed down to re-A duce the effectiveness of manifold vacuum on the piston during certain phases of engine operation. A conduit 78 is formed in casing 68 and communicates with piston bore 66 and the thermostatic chamber 80, the latter which may be maintained at atmospheric pressure or, as will subsequently be considered, may be in communication with a stove or heating mechanism. Under certain operating conditions conduit 78 is adapted to be communicated with conduit 76 in vacuum piston 64 as will be seen from a description of the operation of the device which follows.

With the engine cold and hence requiring an enriched fuel-air mixture thermostatic element 60 will retain the modifier valve 50 in its closed position as shown in Figure 2. ln such position a maximum metering signal will be transmitted through venturi chamber 38 and conduit 36 to diaphragm chamber 34 which will position the metering valve 22 in a maximum fuel flow condition. After the engine begins to fire manifold vacuum will shift the vacuum piston 64 to the position shown in Figure 2a in which the signal modifier valve is partially opened and also in which position piston conduit 76 communicates with conduit 78 to bleed down the manifold vacuum force acting on the piston. This will cause the modifier valve 50 to be retained in the partially opened position until such time as the engine warms sufficiently to permit the thermostatic coil member 60 to relax and open the valve sufficiently more to move the vacuum piston 64 to interrupt the registry between conduits 76 and 78 permitting manifold vacuum to again urge the valve to a still further open position.

In order that the final amount of opening of the modifier valve 50 be under the control of the thermostatic coil member 60 a lost motion pin and slot connection 82 and 84 is formed between lever 72 and link 70 so that after manifold vacuum causes the piston 64 to bottom within the casing bore 66 as shown in Figure 2b, the bimetallic coil will complete the final opening of the valve.

If it is desired to make the coil 60 more accurately responsive to engine temperature, it is possible, as suggested above, to communicate the thermostatic chamber 80 with a source of engine heat such as the exhaust manifold. In this event the manifold vacuum acting on vacuum piston 64 will draw such heated air across the thermostatic member when conduits 76 and 78 are in registry. It is apparent that, if such is desired, the device may be modified to continuously draw heated air through chamber 80.

If it is preferable to eliminate the stepped type control of the air valve which is achieved by providing the conduits 76 and 78, it is possible to eliminate the latter conduits whereby manifold vacuum will continuously act on the piston 64 to provide an even engine load modulation of the action of the thermostatic element 60.

During cold starting and cold running operation engine friction is higher than during warm engine operation. For this reason it is normal practice to provide means for supplying a greater charge to the engine when the latter is cold than when it is warm. For this purpose a fast idle cam member 86 is mounted on the induction casing 52. Cam 86 includes a stepped cam surface 88 with which an adjustable screw member 90 mounted on a lever 92 fixed to the throttle shaft 94 can coact to regulate the quantity of air which flows past the throttle 16 under idling conditions. Thus as engine temperature increases, the fast idle cam is adapted to be rotated in a clockwise direction, as viewed in Figure 2, causing the screw 90 to progressively engage lower steps of the cam and reduce the engine idling speed. The rotation of the fast idle cam 86 is adapted to be controlled by the thermostatic element 60 to which it is articulated through a suitable link 96 and lever 98.

If it is desired to reduce the longitudinal displacement or length of the induction passage casing, it is possible to utilize a pair of signal modifying valves and 102 as shown in the modification of Figures 3 and 4. In this event, the individual valves 100 and 102 are mounted on separate shafts 104 and 106 and have unbalanced areas in order to be air fiow responsive as in the modification of Figures 1 and 2.

Further, if it is desired for better heat response or other reasons to mount the thermostatic controlling mechanism other than on the modulating valve shaft 56, as shown in Figures l and 2, it is possible to position this mechanism 58' elsewhere, as shown in Figure 3. In this case the mechanism 58 is connected through suitable levers and links 108, 110, 112, 114 and 116 to the signal modifying valve shafts 104 and 106. -In the case of the modification of Figure 3, a link 118 articulated between the thermostat lever 120 and fast idle cam 86 determines the idle position of throttle shaft 94.

It is apparent that various modifications may be made in the present device within the scope of the invention as set forth in the appended claims.

We claim:

l. A fuel injection system for an internal combustion engine comprising an air induction passage, an annular venturi means disposed in said induction passage, a throttle valve in said induction passage posteriorly of said venturi means, a plurality of intake passages communicating the induction passage with the individual cylinders of said engine, a source of fuel under pressure, conduit means for communicating said fuel source with the intake passages, a metering valve intermediate said fuel source and said conduit means, diaphragm means for actuating said metering valve, an annular chamber formed in said induction passage and communicating with said venturi means, a conduit communicating said chamber with said diaphragm means for increasing the flow through said metering valve with an increase in air flow through said venturi, air fiow responsive valve means disposed in said induction passage anteriorly of said venturi means, a temperature responsive member operatively connected to said air fiow responsive valve means for resiliently holding said valve means in a closed position to increase the vacuum force in said induction passage chamber whereby said metering valve will insure an enriched fuel-air mixture when the engine is cold, said temperature responsive member being adapted to open said air fiow valve as the engine warms, and engine load responsive means for modifying the operation of the temperature responsive member.

2. A fuel injection system for an internal combustion engine comprising an air induction passage, an annular venturi means disposed in said induction passage, a throttle valve in said induction passage posteriorly of said venturi means, a plurality of intake passages communicating the induction passage with the individual cylinders of said engine, a source of fuel under pressure, conduit means for communicating said fuel source with the intake passages, a metering valve intermediate said fuel source and said conduit means, diaphragm means for actuating said metering valve, an annular chamber formed in said induction passage and communicating with said venturi means, a conduit communicating said chamber with said diaphragm means for increasing the flow through said metering valve with an increase in air ow through said venturi, air flow responsive valve means disposed in said induction passage anteriorly of said venturi means, a temperature responsive member operatively connected to said air fiow responsive valve means for resiliently holding said valve means in a closed position to increase the vacuum force in said induction passage chamber whereby said metering valve will insure an enriched fuel-air mixture when the engine is cold, said temperature responsive member being adapted to open said air flow valve as the engine warms, and manifold vacuum responsive means operatively connected to said air flow valve for urging said valve in an open direction as manifold vacuum increases.

3. A fuel injection system for an internal combustion engine comprising an air induction passage, an annular venturi means disposed in said induction passage, a throttle valve in said induction passage posteriorly of said venturi means, a plurality of intake passages communicating the induction passage with the individual cylinders of said engine, a source of fuel under pressure, conduit means for communicating said fuel source with the intake passages, a metering valve intermediate said fuel source and said conduit means, diaphragm means for actuating said metering Valve, an annular chamber formed in said induction passage and communicating with said venturi means, a conduit communicating said chamber with said diaphragm means for increasing the ow through said metering valve with an increase in air ow through said venturi, air ow responsive valve means fixed for rotation on a shaft in said induction passage anteriorly of said venturi means, a bimetallic temperature responsive coil concentrically disposed about and fixed at one end to said shaft, said coil xed against movement at its other end for resiliently holding said valve means in a closed position against the force of air ow to increase the vacuum force in said induction passage chamber whereby said metering valve will insure an enriched fuel-air mixture when the engine is cold, said coil being adapted to open said airflow valve as the engine warms, a piston mounted on the induction passage and articulably connected to the air ow valve shaft, and conduit means communicating manifold vacuum with said piston to urge the air ow valve in an open direction as engine load decreases. Y

4. A fuel injection system as set forth in claim 3 in which said vacuum piston is connected through a lost motion mechanism to the air ow valve shaft whereby under certain operating conditions manifold vacuum is inoperative to eifect the position of said valve.

5. A fuel injection system for an internal combustion sages communicating the induction passage with the individual cylinders of the engine, -a source of fluid under pressure, conduit means communicating said fuel source with the individual intake passages, valve means for metering the quantity of fuel flow through said conduit means, diaphragm means for controlling the actuation of said valve, `a venturi in said induction passage, a conduit communicating with said venturi and said diaphragm means whereby said latter means is actuated to increase the output of said metering valve in proportion tothe mass of air flow through said venturi, a throttle valve dis posed in said induction passage posteriorly of said venturi, and valve means disposed in said induction passage anteriorly of said venturi for modifying thediaphragm metering control force in accordance with certain engine operating conditions.

6. A fuel injection system for an internal combustion engine comprising an air induction passage, intake passages communicating the induction passage with the individual cylinders of the engine, a source of fluid under pressure, conduit means communicating said fuel source with the individual intake passages, valve means for metering the quantity of fuel ow through said conduit means, diaphragm means for controlling the actuation of said valve, a venturi in said induction passage, a conduit communicating with said venturi and said diaphragm means whereby said latter means is actuated to increase the output of said metering valve in proportion to the mass of air ow through said venturi, a throttle valve disposed in said induction passage posteriorly of said venturi, and valve means disposed in said induction passage anteriorly of said venturi for modifying the diaphragm metering control force in accordance with certain engine operating conditions, a cam for limiting the idle position of the throttle valve and means connecting said valve means and cam whereby the position of said cam is determined by the position of said valve means.

References Cited in the le of this patent UNITED STATES PATENTS 2,785,669 Armstrong Mar. 19, 1957

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