US2560262A

US2560262A - Automatic antidetonation system

Info

Publication number: US2560262A
Application number: US509336A
Authority: US
Inventors: Francis J Wiegand; Erold F Pierce
Original assignee: Wright Aeronautical Corp
Current assignee: Wright Aeronautical Corp
Priority date: 1943-11-06
Filing date: 1943-11-06
Publication date: 1951-07-10
Anticipated expiration: 1968-07-10

Description

July 10, 1 51 F. J. WIEGAND ETAL AUTOMATIC ANTIDETONATION SYSTEM 6 Sheets-Sheet 1 Filed Nov. 6, 1943 INVENTORS FRANCIS J W/EGAND y EROLD F. PIERCE y 1951 F. J. WIEGAND ETAL 2,560,262

AUTOMATIC ANTIDETONATION SYSTEM Filed NOV. 6. 1943 6 Sheets-Sheet 2 FRANCIS J W/EGAIVD y 1951 I F. J. WIEGAND ET AL 2,560,262

AUTOMATIC ANTIDETONATION SYSTEM Filed Nov. 6. 1943 6 Sheets-Sheet 5 f'nont'uam: 60 MAM/FOLDPnsssun:

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July 10, 1951 F. J. WIEGAND ET AL 2,560,262

AUTOMATIC ANTIDETONATION SYSTEM Filed Nov. 6, 1945 e Sheets-Sheet 5 TOTHE WATER DISCHARGE NOZZLES fl-G F I46. f fizom ENGINE lh/TAKE MANFOLD INVENTORS FRANCIS J WIEGAND y 10, 1951 F. J. WIEGAND EI'AL 2,560,262

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INVENTOR FRA/vc/s .I W/EGAND EROLD F. PIERCE AFTNEY Patented July 10, 1951 AUTOMATIC ANTIDETONATION SYSTEM Francis J. Wiegand, Ridgewood, and Erold F. Pierce, Pines Lake, N. J., assignors to Wright Aeronautical Corporation, a corporation of New York Application November 6, 1943, Serial No. 509,336

25 Claims.

This invention relates to means for inhibiting detonation in an internal combustion engine and is particularly directed to an anti-detonation fluid injection system permitting emergency high power engine operation without detonation.

The power available from an internal combustion engine is limited b the occurrence of detonation in the engine combustion chambers. This is particularly true of engines equipped with superchargers since supercharging not only increases the pressure of the combustion air or mixture and, therefore, the power output of the engine, but also increases the temperature, thereby tending to cause detonation. That is, the usable amount of pressure boost obtainable from supercharging is limited by the occurrence of detonation within the engine. It is known that the addition of a cooling medium such as water into the combustion chamber reduces the temperature within the chamber, thereby permitting engine operation at higher intake manifold pressures without the occurrence of detonation. The water or other anti-detonant used reduces the temperature within the combustion chamber since evaporation of the watertherein absorbs considerable heat. It is also old to introduce special anti-knock fuels into the engine to inhibit detonation. However, the particular antidetonant used forms no part of the present invention.

It is an object of this invention to provide an improved system of anti-detonation liquid injection and engine power control in order to provide detonation-free high power engine operation. It is a further object of this invention to provide an anti-detonant injection system in which the engine power is automatically increased substantially simultaneously with the injection of the anti-detonant within the engine. In addition, it is an object of this invention to provide an anti-detonant injection system for emergency engine power operation in which the engine power is automatically reduced when the supply of anti-detonant is exhausted.

In order to increase the maximum amount of detonation-free power available from an internal combustion engine, it is common practice to enrich the fuel-air ratio above a predetermined engine power. Apparently the extra fuel inhibits detonation. It is a further object of this invention to inhibit detonation at these higher engine powers by introducing an anti-detonant into the engine instead of by increasing the fuel-air ratio.

A further object of this invention consists in the provision of an engine power regulator which employed in the system of Fig. 1.

Fig. 3 illustrates the system of Fig. 1 as applied to an aircraft engine equipped with a turbosupercharger,

Fig. 4 is a modification of the fluid control valve illustrated in Figures 1 and 3 for controlling the discharge of anti-detonant into the engine,

Figs. 5, 6, and '7 disclose modified arrangements of the power control valve illustrated in the systems of Figures 1 and 3 for respectively controlling the operation of their boost or turbo-regulators,

Fig. 8 illustrates a further application of an anti-detonation injection system to an internal combustion engine,

Fig. 8A illustrates a modification of the system of Fig. 8; and

Fig. 9 is a further modification in which a pump is used to discharge the anti-detonant into the engine.

Referring to Fig. 1, a conventional aircraft engine 50 is provided with a carburetor II and a carburetor adapter I2 which comprises a duct extending from the carburetor and communicating with the intake side of a supercharger Id. The supercharger discharges combustion air or mixture into an annular manifold l5 from which it is distributed to the various engine cylinders IS. A so-called boost pressure regulator l8 automatically operates to control the carburetor throttle for maintaining a desired manifold pressure. The details of the boost regulator form no part of the present invention and any suitable regulator may be used.

As illustrated in Fig. 2, the regulator l8 may comprise a bellows 20 which is responsive to the engine intake manifold pressure through the pipe connection 22 and a tension spring 24, connected at its lower end to the bellows 20 and at its upper end to a rod 25, opposes expansion of this bellows. The bias of the spring 24 is adjustably controlled through thebell crank control lever 26 pivotall connected to the rod 25 to provide manual control of the boost regulator. Movement of the bellows 20 is transmitted to a pilot valve 28 of a fluid motor 88. An increase in the engine intake manifold pressure or a reduction in the tension of the spring 24 by counterclockwise movement of the control lever 26 (Fig.

i 2) results in an expansion of the bellows 28 to deflect the pilot valve 28 in a downward direction. Thereupon fluid pressure is admitted from the pressure supply line 32 through passage 34 to the lower end of the fluid motor .and simultaneously the upper end of the fluid motor is connected to a drain passage 36 through the passage 38, thereby operating the fluid motor piston 40 in an upward direction to provide a closing adjustment of the carburetor throttle 42. Similarly, a reduction in the engine manifold pressure or an increase in the tension of the spring 24 when lever 28 is moved clockwise results in a downward movement of the piston 40 to provide an opening adjustment of the carburetor throttle. As illustrated, the piston 48 is connected to the carburetor throttlev 42 by means of a sliding pivoted connection with a lever 4| having a fixed pivot at one end and pivotally connected at its other end to one end of a lever 43, the other end of which is pivotally connected to an arm 45 rigid with the carburetor throttle 42. The bellows 20 expands against an evacuated bellows 44; that is, against a fixed absolute pressure whereby the boost regulator operates to maintain the desiredmanifold pressure regardless of the pressure of the atmosphere. The engine and boost regulator structure so far described is conventional.

The extent to which the engine intake manifold pressure may be increased is limited by detonation of the engine at high manifold pressures. It is known that the introduction of water or other anti-detonant having a high latent heat of vaporization considerably reduces the temperature within the combustion chamber because of the quantity of heat absorbed in vaporizing this liquid in the combustion chamber. This reduction of temperature permits engine operation at higher intake manifold pressures with a corresponding increase in engine power. The provision of means to inject such an anti-detonant into the combustible mixture is particularly desirable in military aircraft in order to provide the extra power necessary to meet the various emergencies that may arise.

Referring back to Fig. 1, a tank 48 for water or other anti-detonant is connected through a metering valve 48 and a conduit 49 to a discharge nozzle 50 (more than one discharge nozzle, if desired, may be provided) which is adapted to discharge water or other anti-detonant into the engine induction system at the carburetor adapter l2 under the control of the pilot, as hereinafter described. The upper level of the water in the tank 48 is subjected to engine intake manifold pressure through the conduit 52, restricted orifice 54, and the spring-biased check valve 56, whereby the manifold pressure provides the force discharging the water through conduit '49 and nozzle 50 when the valve48' opens. That is, the anti-detonant is discharged through the nozzle 50 by the differential pressure between the engine intake manifold pressure and the pressure in the carburetor adapter 12. At this point it should be noted that a pump could be used to provide the differential pressure for discharge of the anti-detonant, as hereinafter described, instead of using the engine manifold pressure. The metering valve 48 is controlled by an evacuated bellows 58 externally subjected to the engine intake manifold pressure by conduit connections 52 and 68. A spring 52-biases the valve 48 in a closing direction. With this arrangement the metering valve 48 is adapted to open when the engine intake manifold pressure exceeds a predetermined value, whereupon water or other anti-detonant is injected into the combustible mixture through the nozzle 50, the rate of discharge of the anti-detonant depending upon the magnitude of the manifold pressure acting against the bellows 58 controlling the metering valve 48, that is, upon the engine power.

A power control valve 84 is arranged to effect operation of the boost regulator l8 to increase the engine manifold pressurewhen water or other anti-detonant is discharged through the conduit 49 upon the occurrence of the aforementioned predetermined manifold pressure. This valve comprises a movable valve element 68 supported by a diaphragm 88. The upper side of this diaphragm is connected to the conduit 49 while the underside of the diaphragm is vented, preferably to the carburetor adapter l2 through conduit 69, and in addition-a spring It acts against the valve to bias the valve in a closing direction.

A restricted orifice I2 is located in a manifold pressure connection to the boost regulator and a vent line 14 extends from this orifice to the normally closed valve element 66. When the valve 86 is closed, the boost regulator operates in its normal manner to maintain the engine intake manifold pressure as set bylthe control lever 26. When the valve '88 is opened the bleed line 14 is vented through a restricted orifice 18, thereby lowering the pressure in the bellows 20 of the boost regulator. The boost regulator, thereupon, operates to adjust the carburetor throttle to increase the engine intake manifold pressure in order to restore the pressure in the bellows 28. In other words, the valve 66, when opened, provides a restricted vent in the manifold pressure connection to the boost regulator, thereby having the same eifect on this regulator as a reduction in the manifold pressure, whereupon the regulator operates to increase the manifold pressure.

The effect of the vent bleed through the line 14 increases with altitude because of the decrease in atmospheric pressure with altitude. .Therefore, with valve 88 open the boost regulator operates to maintain a higher engine intake manifold pressure at high altitudes than at low altitudes. Accordingly, a safety spring-biased check valve 18 is shunted around the restricted orifice 12 in order to limit the pressure drop across this orifice produced by the flow therethrough when the valve 68 is opened. Thus, the checkvalve 18 provides an upper limit to the pressure drop which can be produced across the restricted orifice 12 when the valve 68 is opened.

The operation of Fig.1 is as follows;

In normal operation the .pilot controls th engine power by operation of the boost regulator control lever 26 and, as lon as the regulator is set to maintain an intake manifold pressure below a certain value, the anti-detonant injection system remains inoperative. Should an emergency arise requiring extra power, the control lever 26 is thrown to an emergency high power position, whereupon the boost regulator adjusts the carburetor throttle for a somewhat higher manifold pressure. This increase in the manifold pressure is sufficient to open the metering valve 48, whereupon the manifold pressure against the water or other anti-detonant in the tank 46 operates to force the anti-detonant through the conduit 49 and nozzle 50 into the air or combustion mixture in front of the supercharger. In addition, the pressure in the conduit 49 is transmitted to the upper side of the diaphragm 68 to open the power valve 66. This valve, when opened, provides a restricted vent for the manifold pressure connection to the boost regulator, whereupon the boost regulator automatically operates to adjust the carburetor throttle for an emergency high intake manifold pressure to provide the necessary emergency power. The water or other anti-detonant enters the combustion chambers of the engine with the combustion mixture to inhibit detonation at this high engine power. After the tank 46 is empty, the sprin bias on the nozzle valve 50 is such that the manifold pressure quickly bleeds out from the tank through the nozzle, whereupon the valve 66 closes the vent line 14 to the boost regulator. That is, although a given pressure, whether exerted by a gas or a liquid, will open the nozzle valve 50 to the same extent, the same nozzle valve opening inherently will offer much less restraint to the discharge of gases therethrough. Accordingly, when the supply of anti-dentonant liquid is exhausted, the manifold gas pressure bleeds out through the nozzle faster than could the anti-detonant liquid and faster than the manifold gas pressure can enter through the restricted orifice 54. Ac-.

cordingly, the nozzle 50 practically closes, thereby maintaining a relatively small back pressure therethrough. Thus when the supply of liquid anti-detonant becomes exhausted, the pressure quickly falls off in line 49 and the valve 66 closes. Obviously, in order to facilitate the escape of manifold gas pressure from line 49, the nozzle valve 50 could be provided with a small bleed opening therethrough which' would be small enough to prevent unrestricted discharge of the liquid anti-detonant therethrough, but would permit the manifold pressure gases to readily escape therethrough into the carburetor adapter from line 49 whenthe nozzle valve 50 was otherwise closed. The regulator, thereupon, operates to reposition the carburetor throttle for a decreased engine power. Similarly, if there is no water or other anti-detonant in the tank 46 when the control lever 26 is thrown to the emergency power position, the fluid valve 48 will open as described above but, because of leakage through nozzle 50, the pressure in the conduit 49 will be insuflicient to open the power valve 66 and, as a result, there is no increase in the power of the engine above its normal detonationfree power range. In other words, although the nozzle 50 offers considerable restraint to the flow of water or other anti-detonant there through, this nozzle offers very little restraint to the escape of manifold pressure when no water is present whereby, in the latter case, the manifold pressure bleeds out through the nozzle 50 faster than it is supplied to the tank 46 through the restricted orifice 54. Therefore, with water or other anti-detonant in the tank 46 when the metering valve 48 opens the pressure in the conduit 49 is substantially equal to the engine manifold pressure plus the head of water in the tank, but with no water or other anti-detonant in the tank the pressure in the conduit 49 is considerably less than the intake manifold pressure.

With the above system the pilot may obtain the normal range of power from the engine by control of the boost regulator in the conventional manner. If emergency power is desired the boost regulator is set for a higher engine power output, whereupon the increase in manifold pressure i operable to effect water ejection into the induction system. Substantially simultaneously therewith a vent is opened in the manifold pressure connection to the boost regulator, whereupon the boost regulator operates to further increase the engine manifold pressure to furnish the emergency power. The injection of the water into the combustion air or mixture inhibit detonation in the combustion chamber at this emergency power. However, if the supply of water or other anti-detonant is exhausted, the system is inoperative to provide the emergency power; or if the supply of water or other antimal engine power.

detonant becomes exhausted during the emergency high power operation the system automatically operates to reduce the engine power to prevent detonation. These latter functions are safety features which prevent operation of the engine above its normal detonation-free power range when the supply of anti-dentonant is exhausted.

As a typical example, the manual control lever '26 of the boost regulator l8 may be provided with a stop setting, indicated by the dashed line 26 in Figure 2, for an engine manifold pressure of 45" of Hg corresponding to the maximum nor- The control lever 26 is also provided with an emergency stop setting, indicated by the dashed line 26" in Figure 2, for a manifold pressure of 47" of Hg, at which pressure the metering valve 48 opens. Also, the vent bleed, when open through line 14, valve 66, and orifice 16, may be designed to provide a pressure drop of 8" of Hg across the restricted orifice 12. With this arrangement, when the boost regulator is set to the emergency stop corresponding to, the manifold pressure of 47" of Hg, the engine manifold pressure will rise to this value, whereupon the metering valve 48 opens and the anti detonant is discharged into the engine induction system. Simultaneously, the power valve 66 opens to provide a pressure drop of 8" of Hg to the boost regulator l8 across the restricted orifice 12. In response to this pressure drop, the boost regulator immediately opens the carburetor throttle to increase the engine manifold pressure from 47 of Hg to 55" of Hg in order to compensate for this 8" of Hg pressure drop. Thus, in this example it is seen that with the aforedescribed anti-detonant injection system the maximum value of detonation-free engine power is increased from an engine power output corresponding to an engine intake manifold pressure of 45" to 47 of Hg to a considerably higher engine power corresponding to an engine intake manfold pressure of 55" of Hg. When the supply of anti-detonant is exhausted, the vent line 14 is closed by the valve 66 so that the full manifold pressure of 55" of Hg is applied to the boost regulator which is still set for a manifold pressure of 47" of Hg. Accordingly, the regulator immediately operates to restore the engine manifold pressure to 47" of Hg, thereby automatically avoiding engine detonation.

Fig. 3 discloses an anti-detonation injection system similar to the above-described anti-detonation injection system but applied to an internal combustion engine equipped with a turbo-supercharger. The systems of Figs. 1 and 3 are essentially the same and similar parts have been designated with similar numerals. In this modification the exhaust from the engine 88 is discharged into an annular exhaust manifold 82 and thence into an annular nozzle box 84 from which the combustion gases are discharged against the buckets 86 of a turbine wheel 88. This turbine wheel is drivably connected to the impeller of a supercharger 92 which supplies compressed air to the carburetor 94. From the carburetor, the combustion air or mixture passes through the carburetor adapter 86 and may be further compressed by an engine-driven supercharger 98 which discharges into the annular intake manifold I88 from which the combustion air or mixture is fed to the various engine cylinders.

The turbo-

supercharger

98, 92 is equipped with a regulator I8 which is similar to the boost regulator I8 system of Fig. 1 except that it is responsive to the turbine nozzle box pressure through the conduit I82 and controls the turbine waste gate I04. Although the turbo-regulator I8 as illustrated is controlled in response to changes in the nozzle box pressure, the invention obviously is not limited to this arrangement and may be used with other conventional arrangements, e. g., in which the turbo-regulator I8 is controlled by the engine intake manifold pressure or by the carburetor inlet pressure. That is, line I82, instead of being connected to the turbine nozzle box 84, instead may be connected to the engine intake manifold or to the inlet side of the carburetor. The details of constructicn of the turbo regulator I8 are similar to that of the boost regulator illustrated in detail in Fig. 2 but any suitable regulator may be substituted therefor.

An anti-detonant supp tank 48 is subjected to engine manifold pressure through a conduit 52, a restricted orifice 54, and a spring-biased check valve 56. An evacuated spring-biased bellows 58 is responsive to the engine intake manifold pressure through the lines 52 and 88 to open the metering valve 48 when the manifold pressure exceeds a predetermined value. When the valve 48 is opened the engine manifold pressure forces the water or other anti-detonant from the tank 46 through the conduit 49, the nozzle 58, and into the engine induction system in front of the engine-driven supercharger. A power control valve 68 is operated by a diaphragm 68 subjected on one side to the pressure in the conduit 48 and on the other side to the pressure in the carburetor adapter 86. The power valve 88. when opened, provides a restricted venting opening I8 for the nozzle box pressure controlling the turbo-regulator through the orifice l2, whereupon the regulator operates to adjust the waste gate in a closing direction to increase the engine intake manifold pressure. In addition, a safety check valve I8 is provided to limit the the pressure drop across the restricted orifice I2, as previously'explained in connection with Fig. l.

The operation of Fig. 3 is essentially the same as Fig. 1 except that the power valve 66 in Fig. 1 acts on the boost regulator to effect the opening adjustment of the carburetor throttle to increase the engine intake manifold pressure, while in Fig. 3 the power valve 68 acts on the turboregulator to eifect a closing adjustment of the turbine waste gate to increase the engine intake manifold pressure. The operation of the antidetonation liquid injection systems of Figs. 1 and 3 are otherwise similar.

described in connection with the- At this point it should be noted that although the invention has been described and illustrated, in Figures 1 and 3, in connection with a supercharged internal combustion engine, the invention obviously is not so limited but can readily be applied to any internal combustion engine whose power output is limited by detonation whether or not the engine has a supercharger in its induction system.

Fig. 4 illustrates a modification of the water flow valve 48 of Figs. 1 and 3. In this modification the movable valve element I84 is supported by the diaphragm I88, subjected on the one side to engine intake manifold pressure through the line 52 and on the other side to the discharge pressure of the valve. In additio a spring I88 biases the valve to its closed position. The discharge side of the valve I84 is connected by conduit II2 to a nozzle II8 which is adapted to discharge water or other anti-detonant from the tank 45 into the carburetor adapter, as in the systems of Figs. 1 and 3, when the valve I84 is opened. The valve I84 is designed to open when the manifold pressure reaches a predetermined value and the nozzle H8 is set to maintain a back pressure lower than the manifold pressure required to open the valve I84. Therefore, even when the valve I84 opens, the pressure above the diaphragm I88 will be less than the pressure below the diaphragm so that the valve I84 will remain open. If the nozzle II8 discharges against a constant pressure in the carburetor adapter, thevalve I84 will have a fixed position regardless of the atmospheric pressure. However, if the carburetor adapter pressure decreases somewhat with altitude, then the valve I84 :will open further at the higher altitudes,

thereby supplying more water at the higher altitudes. This is desirable because, at a constant engine intake manifold pressure, the engine power increases with increase in altitude.

The fluid valve I84, Fig. 4, has a fixed open position for a given manifold pressure regardless of the altitude if the carburetor adapter pressure is maintained substantially constant or, if the carburetor adapter pressure decreases with increase in altitude, the extent to which the valve I84 opens will also increase with altitude. This valve I84 may be substituted in either Figs. 1 or 3 and has the advantage that no evacuated bellows 58 is necessary.

Figs. 5 and 6 disclose modifications of the power control valve. Both of these modifications may be used either with the system of Fig. l or that of Fig. 3, although they have been illustrated and are hereinafter described in connection with the system of Fig. 1. In Fig. 5 the metering valve 48 is responsive to the engine intake manifold pressure through the lines 52 and 68 for opening this valve when the manifold pressure exceeds a predetermined value. When the valve 48 is open, the manifold pressure acting on the anti-detonant in the tank 46 forces the antidetonant through the valve 48, line 48, and through the discharge nozzle mounted on the carburetor adapter. The power control valve I28 is spring-urged toward closed position and is connected to a diaphragm I22 communicating on the one side to the water supply tank 48 and on the other side this diaphragm is vented through a restricted orifice I24. The valve I28, when open, provides a vent bleed for the pressure connection to the manifold pressure regulator through the line 14, valve I28, and restricted The power control valve I 20 may be designed to open whenever engine intake manifold pressure is applied to the water or other anti-deto nant in the tank 46. With this arrangement the valve I20 normally unbalances the manifold pressure regulator I8 so that this pressure regulator maintains a higher value of engine power for a given setting of the regulator if water or other anti-detonant is present than if the supply of anti-detonant is exhausted. When the manifold pressure regulator is set to effect an increase in the engine power above its normal power range, the resulting increase in manifold pressure operates to open the metering valve 48, where: upon water or other anti-detonant is discharged into the engine induction system. The discharge of anti-detonant into the engine induction system permits an increase in the engine power above its normal range without causing detonation. When the supply of water or other anti-detonant is exhausted the pressure in the supply tank 45 quickly drops as previously described, thereby effecting closure of the power control valve I 20 and its associated restricted orifice I24 in the vent bleed connection to the manifold pressure regulator. With this closing of the vent bleed connection to the manifold pressure regulator, the regulator operates to reduce the manifold pressure and the power output of the engine. That is, the function of the power control valve is to prevent emergency high power engine operation when the supply of water or anti-detonant is exhausted; or if this supply should become exhausted during high power operation, the power control valve functions to reduce the engine power.

The power control valve I20, instead of opening whenever the manifold pressure is applied to the liquid in the tank 46, may be designed to open ata predetermined value of manifold pressure corresponding to the maximum value of detonationfree engine power available without the addition of an antidetonant. With this arrangement, whenever the manifold pressure regulator is set to maintain a pressure above this predetermined value, the valve I 20 opens to unbalance the manifold pressure regulator and this regulator thereupon operates to increase the manifold pressure for emergency high power operation. The metering valve 48 is adapted to open substantiall simultaneously wtih this opening of the power valve I 20, or the increase in manifold pressure effected by this opening of the power valve may cause th metering valve 48 to open, whereupon the anti-detonant is discharged into the engine induction system. When the supply of anti-detonant is exhausted, the pressure in the tank 46 quickly drop thereby closin power control valve I20 and its associated restricted orifice I 24. With this closing of the vent bleed connection to the manifold pressure regulator, the regulator automatically operates to reduce the manifold pressure for normal engine operation. In other words, when emergency power is desired, the engine output is increased in the normal manner by controlling the manifold pressure regulator to the point where the power control valve opens to automatically effect a further increase in the manifold pressure, and at the same time metering valve 48 opens to effect introduction of an antidetonant into the engine induction system. In

addition, when the anti-detonant supply is exhausted, the pressure immediately drops within the tank 46, whereupon the valve I20 closes and the manifold pressure regulator repositions itself 10 to reduce the manifold pressure to its normal value.

The system of Fig. 6 is similar to Fig. 5 except that a pair of serially connected valves I26 and I28 hav been added to assist, if necessary, in quickly effecting a reduction in the engine power when the water supply is exhausted. The added valve I26 comprises a movable gate-type valve element carried by the power valve I20. The power valve I20, with its operating diaphragm I 22 and associated vent I24, is connected in parallel with the serially disposed valves I26 and I 28. The valve I26 is adapted to open when the power valve I 20 closes and vice versa. Accordingly, when the power control valve I20 closes the pressure regulator bleed connection through restricted orifice I24, the valve I26 is open, and if the valve I28 is also open, then manifold pressure is admitted through the serially disposed valves I26 and I28 from lines 52 and I30 to the manifold pressure regulator. The valve I28 is similar to the valve 48 and this valve is adapted to open when the manifold pressure exceeds the predetermined value at which the valve 48 opens.

During emergency high power engine operation the power valve I20 and water metering valve 48 open as described in connection with Fig. 5

and, in addition, with valve I20 open, valve I26 is closed and the valv I28, connected in series therewith, is open. When the water supply is exhausted, the power valve I 20 closes, thereby opening the valve I26. Manifold pressure is thereupon admitted through lines 52 and I 30 and through the serially connected valves I26 and I 28 directly to the manifold pressure regulator to quickly effect a reduction in the manifold pressure. Normal operation of the pressure regulator is restored as soon as the resulting reduction in manifold pressure effects a closin of the valve I28. In the absence of the provision of the valves I 26 and I28, when the water supply is exhausted and the vent bleed connection to the manifold pressure regulator is closed by the power control valve, it is necessary for the manifold pressure to build up through the restricted orifice I2 before the pressure regulator can effect a reduction in the manifold pressure. However, with the valves I26 and I28 operable as described, when the pewer control valve closes there is no such delay, since the manifold pressure is immediately placed in unrestricted communication with the regulator through valves I26 and I28.

In Fig. 6 the valves I26 and I28 in effect have been added to the power control valve I 20 unit illustrated in Fig. 5. It seems clear that valves I26 and I28 could be added to the power control valve unit 64 in a similar manner and for the same purpose; namely, to effect a quick reduction in the engine power when the supply of anti-detonant is exhausted.

With the conventional manifold pressure regulator illustrated in Figs. 1 and 2, the regulator operates to maintain a constant manifold pressure regardless of variations in atmospheric pressure. However, the engine exhaust back pressure decreases with altitude and, therefore, with a constant engine intake manifold pressure, the engine power will increase with altitude. Accordingly, in order to maintain a constant engine power for a given setting of the regulator, the regulator should operate to maintain a decreasing manifold pressure with increasing altitude.

In the case of a turbo-supercharger installation, the conventional turbo waste gate regulator operates to maintain a constant turbine nozzle box pressure. hausts into the atmosphere, the power absorbed by the turbine will increase with altitude because addition to the power control valve which is' operative to so adjust the pressure regulator with variations in altitude in order to maintain a constant engine power for a given setting of the regulator. This modification has been illustrated in connection with Fig. 1 but, as will appear, this modification is equally applicable to the system of Fig. 3 for adjusting the turboregulator for constant engine power independent of altitude. An aneroid control valve I32 is disposed in the bleed line I4 from the pressure regulator I3. The valve I32 is movable by a sealed bellows I33 in response to variations in atmospheric pressure transmitted to said bellows through conduit I35, and is designed to close at a particular altitude, e. g., 20,000 feet, and to open at lower altitudes to provide a vent bleed connection to the regulator in which the bleed opening decreases with increase of altitude and vice versa. The discharge side of the valve I32 is connected to an evacuated chamber I34 which is maintained at a constant pressure by a vacuum pump I36. The regulator is vented to an evacuated chamber instead of to the atmosphere in order to obtain a sufficient bleed through the line I4 and valve I32 to obtain the desired pressure drop across the restricted orifice I2 to the pressure regulator at the lower altitudes.

With the above arrangement the valve I32 provides a maximum bleed from the pressure connection to the regulator atlow altitudes and this bleed gradually decreases as the altitude increases. Therefore, ,in the case of the boost regulator, with a given setting of the regulator, the manifold pressure will decrease with in-, crease of altitude and the valve I32 is so profiled that constant engine power is maintained for a given setting of the regulator. Similarly, in combination with a turbo-regulator, the operation of valve I32 results in a decreasing turbine nozzle box pressure with increase in altitude for a given setting Of the regulator, and the valve I32 is so designed that a constant engine power is maintained.

The power control valve I38, illustrated in Fig. '7, is connected in parallel with the aneroid valve I32 and is designed to open to provide a vent bleed from the turbo-regulator through the restricted orifice I40. The power valve I33 is supported from a diaphragm I33 and is springurged toward a closed position. One side of the diaphragm I39 is in communication with the anti-detonant supply tank 46 and the other side is vented to the evacuated chamber I34 through a restricted orifice I40 when the solenoid valve I42 is open. As in the previous modifications, the tank 46 is subjected to the engine intake manifold pressure through a check valve 56. The valve I33 is designed to be opened by the combined manifold and anti-detonant pressure acting against the diaphragm I33 at normal high However, since the turbine expower engine operation. Then if emergency power is desired, a suitable manual switch may be closed to energize the solenoid of valve I42 or as illustrated, power control lever 23 may be operated to energize this solenoid by closure of switch contacts I and I43 above a predetermined engine power setting. Thereupon valve I42 opens to provide a bleed path from the line I4 through the valve I33. As a result of this additional bleed through the line I4 from the pressure regulator, the regulator repositions itself for directly increasing the manifold pressure in the system of Fig. l, or for increasing the nozzle box pressure in the system of Fig. 3. At the same time, the metering valve 43 is designed to be opened by manifold pressure, whereupon water is discharged into the combustible mixture through the nozzles at the carburetor adapter. In'other words, when above-normal engine power is desired, solenoid valve I42 is opened to provide a vent bleed to the pressure regulator, the regulator operates to reposition itself and increase the engine power, and the accompanying discharge of anti-detonant into the combustible mixture inhibits detonation at this increased power. When the supply of anti-detonant is exhausted power control valve I33 closes as in the previous modifications, thereby reducing the engine power to its normal value even though the solenoid valve I42 is still open.

In order to increase the normal detonationfree power range of an internal combustion engine, it is common practice to gradually increase the fuel-air ratio above a predetermined power, e. g., by means of a so-called carburetor enrichment-valve. Apparently, the extra fuel has a cooling efiect in the engine and, in addition, slowsup combustion, thereby inhibiting detonation. In any case, by increasing the fuel-air ratio at the higher engine powers, more power may be obtained from the engine before detonation occurs. It is possible to operate the engine at these higher'powers without increasing the fuel-air ratio if an anti-detonant such as, water is injected into the combustible mixture. Fig. 8 illustrates such a further application of an antidetonation injection system. The engine has not carburetor has been illustrated which relates to means for automatically enriching the fuelair ratio at higher engine powers.

In Fig. 8 (as in Figures 1 and 3) the water or other anti-detonant supply tank 43 is subjected to engine manifold pressure through the line I48 and check valve 53 and is adapted to discharge the anti-detonant through the metering valve 43, line I43, and the discharge nozzles at the carburetor adapter. A solenoid valve I50 is disposed in line I43 and this valve is urged by a spring to a position for closing the line I43. As illustrated, a diaphragm I33 through conduits I32 and I54 respectively, has its opposite sides connected across the restriction I35 in line I43, whereby upon flow of anti-detonant through line I43, the diaphragm I33 is subjected to the pressure differential across the restriction I65 to urge the diaphragm to the left, as viewed in the drawing. A plunger element I64 is carried by the diaphragm I60 and is arranged to cooperate with a conventional carburetor automatic enrichment valve I66 forming part of a conventional carburetor to prevent this valve from opening when combined anti-detonant and manifold pressure is applied to the diaphragm I33 through line I54. The details of the power en- 13 richment valve and the associated carburetor structure form no part of the present invention and the invention may be used with any other equivalent means for automatically increasing the fuel-air ratio at higher engine powers.

As illustrated in Fig. 8, conventional carburetor fuel-metering jets I68 and I10 are disposed in the fuel line I12 through which the carburetor controls the fuel flow in proportion to the air flow. An automatic enrichment valve I66 is disposed in parallel with the jet I10. The valve I66 is urged to a closed position by a spring I14 and is connected to a diaphragm I16. One side of the diaphragm I16 is subjected to the fuel pressure on the upstream side of the jet I68 through a passage I18 for urging the valve in an opening direction. The other side of the diaphragm I16 is subjected to the fuel pressure on the downstream side of the jet I68. That is, the diaphragm I16 is subjected to a pressure differential proportional to the magnitude of the fuel flow as measured by the pressure differential across orifice I68. Accordingly, the valve I66 is designed to open above a predetermined fuel flow in the fuel line I12 to an extent determined by the magnitude of said flow, thereby increasing the fuel-air ratio as the engine power is increased by providing a fuel passage in parallel with jet I10. As previously explained, the reason for thus enriching the combustible mixture is to inhibit detonation at the higher engine powers.

With the arrangement illustrated in Fig. 8, detonation may also be inhibited at these higher engine powers by opening the solenoid valve I50, whereupon the anti-detonant is discharged into the intake system, the metering valve 48 having previously been opened by the manifold pressure. As soon as the solenoid valve I50 opens, the combined water and manifold pressure in the line I48 acts against the diaphragm I60 which thereupon flexes to position the plunger or stop member I64 against the enrichment valve I66 to prevent opening of this valve.

The circuit on the solenoid valve I50 may be controlled by a substitute manual switch or by a switch comprising contacts II and I53 adapted to be closed by an engine power control lever, which, for example, may comprise the control lever 26 of the power control regulator I8 or I8 illustrated in Figures 1 and 3 respectively. The switch contacts I 5| and I53 are arranged to be closed by the control lever 26 when this lever is set for a predetermined engine power at which either the fuel-air ratio of the combustible mixture must be increased or an antidetonant must be added to the combustible mixture in order to inhibit engine detonation. Closure of switch contacts I5I and I53 results in energization of the solenoid to open the valve I50, whereupon the anti-detonant is discharged into the engine induction system and the plunger I 64 prevents the enrichment valve I66 from opening, all as already described. If the supply of anti-detonant should become exhausted during this operation, then the pressure differential across restriction I 65 immediately decreases, since the restriction I65 offers much less resistance to the flow of a gas, whereupon the plunger I64 no longer prevents opening movement of the power enrichment valve I66.

If the water or other anti-detonant is only used to inhibit detonation in lieu of enriching the combustible mixture, then the quantity of anti-detonant required is quite small, and therefore, metering this small quantity of anti-detonant is not entirely essential. Thus, the metering valve 48 could be dispensed with, and the bellows 58, instead of controlling this valve, could be arranged to close a switch in the circuit of solenoid I50 above a predetermined engine manifold pressure to effect introduction of the antidetonant into the engine induction system. Such an arrangement is illustrated inFigure 8A in which the bellows 58 is responsive to the engine manifold pressure and is adapted to close switch contacts I SI and I53 to energize the solenoid and open the valve I50 above a predetermined manifold pressure. Figure 8A is otherwise similar to Figure 8. With either the arrangement of Figure 8 or Figure 8A the engine may be operated in its normal high power range by introducing an antidetonant into the engine induction system to inhibit detonation instead of inhibiting detonation by increasing the fuelair ratio of the combustible mixture.

Instead of using the engine intake manifold pressure as the motivating force for discharging the water or other anti-detonant from the tank 46, a pump may be used for this purpose in any of the previously described modifications. Such an arrangement is illustrated in Fig. 9 in which the anti-detonant supply tank 46 is vented to the atmosphere through a check valve I80. A pump I82 is disposed in the discharge line I84 from the tank 46 and an electric motor I86 is drivably connected to the pump. The circuit for the motor I86 includes a switch I88 which may be controlled by the control lever 26 of the pressure regulator I8. In this way the pump I82 may be operated whenever the control lever is set for a pressure corresponding to an engine power at which injection of an antidetonant into the engine induction system is desired. The metering valve 48 is disposed in the line I 84 and is responsive to the engine intake manifold pressure for regulating the flow of anti-detonant through line I89 to the discharge nozzles as in the previous modifications. Also, in order to prevent operation of the pump I82 when the tank 46 is empty, a pair of spaced electric contacts I90 are disposed in the conduit I 84 on the inlet side of the pump. It has been found that when the conduit space between the contacts I90 is filled with water or other anti-detonant, that the electric resistance between the contacts is lowered sufficiently to permit the operation of a so-called micro-ampere relay I92 having a switch I94 in the circuit of the motor I86. Therefore, when the supply of anti-detonant is exhausted, the relay I92 is de-energized and the switch I94 opens the circuit to the pump motor I82.

Any one of the previously described power control valves 66, I20 or I38 may be controlled by the pressure in line I89 for opening a restricted vent such as 16, I24 or I40 in the pressure line 14 for automatically increasing the engine power when anti-detonant is being discharged into the engine induction system. Instead, however, Fig. 9 illustrates a solenoid-operated power control valve I95 which, when operated, opens a restricted vent in the line 14 to the atmosphere through restricted orifice I88 to the pressure regulator. The solenoid I95 is controlled by a switch I96 of a so-called micro-ampere relay I91 in circuitwith contacts I98, disposed in spaced relation in the conduit I 89. With this arrangement, when the anti-detonant is being discharged through the conduit I89 into the en gine induction system, the relay I91 is energized amazes to close its switch I96, whereupon the solenoid valve I95 opens the restricted vent in the line 14 to the pressure regulator. The pressure regulator thereupon automatically operates to increase the engine power as previously described. When the supply of water or other anti-detonant is exhausted, the relay I81 is de-energized and the solenoid valve I95 closes the vent in line 14 to the pressure regulator, whereupon the regulator automatically operates to reduce the engine power output. Obviously, the solenoid-operated power control valve I95 with its control circuit could be substituted for any of the fluid pressure-operated power control valves 66, I20 or I38 previously described.

While we have described our invention in detail in its present preferred embodiment, it will be obvious to those-skilled in the art, after understanding our invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. We aim in the appended claims to cover all such modifications and changes.

We claim as our invention:

1. A' systemfor inhibiting detonation in an internal combustion engine comprising means automatically operative in response to an increase in engine power above a predetermined value for effecting introduction of an anti-detonant into the engine, and means automatically operative when the supply of anti-detonant is exhausted for effecting a reduction in the engine power.

2. In an internal combustion engine, means automatically operative in response to an increase in the engine power above a predetermined value for effecting introduction of an antidetonant into said engine, said means including a valve automatically adjustable with engine power for varying the rate of introduction of said anti-detonant into said engine, and means automatically responsive to depletion of said antidetonant supply for reducing the power of said engine.

I 3. In an internal combustion engine, means automatically responsive to an increase in the engine power above a predetermined value for effecting introduction of an anti-detonant into said engine, the pressure differential across a portion of the engine induction system providing the motivating force for introducing said antidetonant, and means automatically operative when the supply of anti-detonant is exhausted for effecting a reduction in the engine power.

4. In an internal combustion engine, an engine power regulator responsive to a pressure associated with the power of said engine, means operable to provide a restricted bleed for said regulator responsive pressure, means automatically responsive to an increase in the engine power above a predetermined value for introducing an antidetonant into said engine, and means operable to close said restricted bleed when said supply of anti-detonant is exhausted to effect a reduction in the power of said engine.

5. In an internal combustion engine, an engine power regulator responsive to a pressure associated with the power of said engine and adapted to automatically increase the engine power upon a decrease in said regulator responsive pressure.

and vice versa, valve means adapted when open 4 to provide a restricted bleed for said regulator responsive pressure to effect a reduction in the pressure to said regulator, means automatically responsive to an increase in the engine power above a predetermined value for introducing an anti-detonant into said engine, and means adapted to automatically open said valve to effect a further increase in power of said engine substantially simultaneously with initiation of said anti-detonant introduction.

6. In an internal combustion engine, an engine power regulator responsive to a pressure associated with the power of said engine and adapted to automatically increase the engine power upon a decrease in said regulator responsive pressure and vice versa, valve means adapted when open to provide a restricted bleed in the pressure connection to said regulator to effect a reduction in the pressure to said regulator, means automatically responsive to an increase in the engine power above a predetermined value for introducing an anti-detonant into said engine, and means adapted to automatically open said valve to effect a further increase in power of said engine substantially simultaneously with initiation of said anti-detonant introduction and adapted to automatically close said valve when the supply of anti-detonant is exhausted to eficct a reduction in the power of said engine.

'7. In an internal combustion engine, an engine power regulator responsive to the intake manifold pressure and adapted to automatically increase the engine power upon a decrease in manifold pressure and vice versa, valve means adapted when open to provide a restricted bleed in the manifold pressure connection to said regulator, means automatically responsive to an increase in the engine manifold pressure above a predetermined value for effecting introduction of an anti-detonant into the engine induction system, and means operable to close said valve when the supply of said anti-detonant is exhausted to effect a reduction in the power of said engine.

8. In an internal combustion engine having an engine exhaust driventurbo-supercharger, a turbo-regulator responsive to a pressure variable with the engine power output and adapted to automatically increase the engine power upon a decrease in said pressure and vice versa, valve means adapted to open a restricted bleed of the pressure connection to said regulator, means automatically responsive to an increase in the engine power above a predetermined value for discharging an anti-detonant into the engine induction system, and means operable to close said valve when the supply of said anti-detonant is exhausted to effect a reduction in the power of said engine.

9. In an internal combustion engine, an engine power regulator responsive to a pressure associated with the power of said engine and adapted to automatically increase the engine power upon a decrease in said regulator responsive pressure and vice versa, a restricted orifice in the pressure connection to said regulator, a valve adapted when open to provide a restricted bleed through said orifice thereby effecting a drop in pressure to said regulator, means automatically respon sive to an increase in the engine power above a predetermined value for introducing an antidetonant into said engine, and means operable to close said valve when the supply of said antidetonant is exhausted and to provide a temporary by-pass pressure connection around said restricted orifice in order to effect a quick reduction in the power of said engine.

10. In an internal combustion engine, an engine power regulator responsive to a pressure .is-

76 sociated with the power of said engine and combustible mixture,

adapted to automatically increase the engine power upon a decrease in said regulator responsive pressure and vice versa, a restricted orifice in the pressure connection to said regulator, a valve adapted when open to provide a restricted bleed through said orifice thereby effecting a drop in pressure to said regulator, means automatically responsive to an increase in the engine power above a predetermined value for introducing an .anti-detonant into said engine, means operable to close said valve when the supply of said antidetonant is exhausted and to provide a temporary by-pass pressure connection around said restricted orifice in order to effect'a quick reduction in the power of said engine, and means to close said by-pass after said engine power has been reduced.

11. In an internal combustion engine, means adjustable to vary the power output of said engine, means automatically operative in response to an increase in the power output of said engine above a predetermined value for effecting introduction of an anti-detonant into said engine, and means automatically operative when the supply of said anti-detonant is exhausted for adjusting said first named means to effect a reduction in the power output of said engine.

12. In an internal combustion engine, means adjustable to vary the power output of said engine, means providing a passage for supplying an anti-detonant into said engine, means adapted to automatically efiect introduction oi said antidetonant through said passage into said engine upon an increase in the power of said engine above a predetermined value, and means adapted to automatically adjustsaid first-named means to effect a further increase in the power of said engine substantially simultaneously with initiation of said anti-detonant introduction.

13. In an internal combustion engine, means adjustable to vary the power output of said engine, means providing a passage for supplying an anti-detonant into said engine, means adapted to automatically eiTect introduction of said antidetonant through said passage into said engine upon an increase in the power of said engine above a predetermined value, and means adapted to automatically adjust said first-named means to efiecta further increase in the power of said engine substantially simultaneously with initiation of said anti-detonant introduction, said lastnamed means including means adapted upon stoppage of said anti-detonant introduction to automatically adjust said first-named means'to reduce the engine power.

14. In an internal combustion engine, means adjustable to vary the power output of said 011- operative in response to an-increase in the power output of said engine above a predetermined value for efiecting introduction of said anti-detonant into said engine by forcing said anti-detonant gine, fluid passage means for supplying an antiv detonant to said engine, means automatically said engine, and means adapted automatically 'to at least partially prevent fuel-air-ratic-increasing movement of said first-named means substantially simultaneously with initiation or said anti-detonant introduction.

16. In an internal combustion engine, first means movable above a predetermined engine power to increase the fuel-air ratio of the engine combustible mixture, second means operable for effecting introduction of an anti-detonant into said engine, and third means automatically operable substantially simultaneously with initiation of said anti-detonant introduction for at least partially preventing movement of said first means to a fuel-air-ratio-increasing position.

17. In an internal combustion engine, means adjustable to vary the power output of said engine, means providing a passage for supplying an anti-detonant into said engine, means adapted to automatically efi'ect introduction of said antidetonant through said passage into said engine upon an increase in the power of said engine above a predetermined value, and means adapted to automatically adjust said first-named means to effect a further increase in the power of said engine substantially simultaneously with initiation of said anti-detonant introduction, said lastnamed means being responsive to the pressure of said anti-'detonant in said passage.

18. An anti-detonant flow control system for internal combustion engines having associated therewith a liquid line for supplying antidetonant to said engine, comprising electrically operated means in said liquid line operable when energized to cause anti-detonant to flow to said engine, an-electric" circuit including said electrically operated means, and control mechanism in said circuit operable in response to the manifold pressure in said engine to prevent energizatlon of said electrically operated means at manifold pressures below a predetermined value and to cause energization thereof when the manifold pressure rises to said predetermined value.

19. In an internal combustion engine; an engine power regulator; a passageway communicating with said regulator for transmitting thereto a fluid under pressure indicative of the engine power output, said regulator" being operative to increase or decrease said power output upon a decrease or increase respectively in the pressure of said fluid at said regulatorj means automatically operative upon an increase intheengine power output above a, predetermined value for effecting introduction of an anti-detonant in said engine and for causing a drop in the pressure of said fluid transmitted thru saidpassageway to said regulator whereupon said regulator is automatically operative to effect a further increase in said engine power; and a pressure-rewvlief valve automatically operative to limit the under pressure through said passage means into said engine, and means automatically operative -in response to a reduction in pressure within said passage means for adjusting said first named means to efiect a reduction in the power output of said engine.

15. In an internal combustion engine, means normally movable above a predetermined engine power to increase the fuel-air ratio of the engine able above said predetermined engine power for eilecting introduction of an anti-detonant into and means selectively operv crease in the engine power magnitude of said pressure drop.

' 20. In an internal combustion engine; an engine power regulator responsive to a fluid pressure'associated with the power of said engine and adapted to automatically increase or decrease the engine power upon a decrease or increase respectively in said pressure at said regulator; a passageway communicating with said regulator and including a valve and a seriallyconnected restriction, said valve when? open permitting fiuid flow through said restriction so that the fluid pressure drop across said restrictionreduces lator; means automatically responsive to' an inabove a predetermined the magnitude of said pressure at said reguvalue for effecting introduction. of an antidetonant into said engine and for opening said valve; and a pressure relief valve connected in parallel with said restriction so that said pressure relief valve limits the magnitude of the fluid pressure drop across said restriction.

21. Control apparatus for controlling the pressure of air supplied to the fuel system of an internal combustion engine in which means are provided for injecting an anti-detonant into the fuel system when abnormal power is needed, said apparatus comprising an adjustable means for selecting the pressure of air and having a wide range of uninterrupted adjustment including a range of pressures sufliciently high that operation of the engine. without injection of the antidetonant would cause injury to the engine, and means responsive to the pressure of the antidetonant effective in the absence thereof to limit said range of adjustment.

22. Control apparatus for adjusting the intake manifold pressure of an internal combustion engine and for injecting an anti-detonant into the engine, comprising adjustable meas for selecting the pressure, said means having a first range of adjustment effective when the anti-detonant is not being injected into the engine and a further range calling for higher pressures when the antidetonant is being used, and means responsive to the injection of the anti-detonant into the engine and operative when the supply of antidetonant fails to override the said adjustable means if in said further range for said higher pressures.

23. Control apparatus for controlling the pressure of air supplied to the fuel system of an internal combustion engine in which means including a source of fluid anti-detonant under pressure are provided for injecting an antidetonant into the fuel system when abnormal power is needed, said apparatus comprising an adjustable means for selecting the pressure of air and having a wide range of uninterrupted adjustment including a range of pressures sufliciently high that operation of the engine without anti-detonant injection would cause injury to the engine, and means adapted to respond to the differential between the pressure of said source of anti-detonant and the pressure within said fuel system for limiting said range of adjustment in the absence of the anti-detonant.

24. In an internal combustion engine; means adjustable to vary the power output of said engine; means adjustable to vary the ratio of fuel and air supplied to the engine; means automatically operative in response to an increase in the power output of said engine above a predetermined value for effecting introduction of an anti; detonant into said engine; means for efl'ecting ply of anti-detonant should 20 adjustment of said fuel-air ratio adjustable means to a relatively low fuel-air ratio during introduction of said anti-detonant and, if the supply of anti-detonant should become exhausted during engine operation above said predetermined value of power output, for effecting adjustment of said adjustable means to a relativelyhigh fuelair ratio; and means automatically operative when the supply of anti-detonant becomes exhausted during engine operation above said predetermined value of power output for efiecting adjustment of said first-named means to reduce said power output.

25. In an internal combustion engine; means adjustable to vary the power output of said engine; means for controlling the ratio of fuel and air supplied to the engine, said means including a valve disposed in a fuel passage and effective to increase or decrease the ratio of said fuel to air upon movement of said valve in an opening or closing direction respectively; means automatically operative in response to an increase in the power output of said engine above a predetermined value for effecting introduction of an anti-detonant into said engine; means automatically operative for positioning said valve in a relatively low fuel-air ratio position during introduction of said anti-detonant and, if the supbecome exhausted during engine operation above said predetermined value of power output, for positioning said valve in a relatively high fuel-air ratio position; and means automatically operative when the supply of anti-detonant becomes exhausted during engine operation above said predetermined value of power output for effecting adjustment of said first-named means to reduce said power out put.

FRANCIS J. WIEGAND. EROLD F. PIERCE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number