US2621472A - Exhaust driven supercharger control - Google Patents

Description

Dec. 16, 1952 s. M. UDALE EXHAUST DRIVEN SUPERCHARGER CONTROL Filed Aug. 16, 1946 I N VEN TOR.

Patented Dec. 16, 1952 OFFICE EXHAUST DRIVEN SUPERCHARGER CONTROL Stanley M. Udale, Detroit, Mich, assignor to George M. Holley and EarlH olley Application August 16, 1946, Serial No. 690,990

7 Claims. (01. 60-13) The object of this invention is to control a supercharger installed on a truck having an ordinary commercial (Otto) cycle internal combustion engine so that the supercharger is most eifective at the lower speeds.

fipecifically the Object is (a) to limit the speed of a gas turbine driven supercharger, and (b) to limit the operation of a gas turbine driven supercharger so that it only operates when needed and operates most effectively when most needed.

A final object is to reduce the governed speed of the gas turbine in ,hot weather and to limit the time during which the gas turbine operates at its maximum speed in hot weather.

The drawing shows diagrammatically the preferred form of my invention.

In the figure, I ll is the inlet manifold, 54 is the air entrance passage leading to it which is an ordinary carburetor attached thereto. 18 is the usual throttle controlled by a manually operated rod 1.2 connected to a slotted link I Hi. This link contains a spring H2. A pin Hit is mounted on the throttle lever Ill. Pin H4 is held to the right hand end of the slot in link llll except when the throttle 18 is wide open. Throttle stop HS limits the opening movement of the throttle IS.

The throttle control rod 72 carries a pin 14 projecting from it. This pin M enga es with a lever l8, loosely mounted von a shaft m4. Lever '58 carries a pin 22 which engages witha-lever 80 which is fastened to the shaft M. Lever Bil is also joined to aconne ting rod .vhich in turn is joined to diaphragm 45.

Chamber 60, a ove diaphragm is, is connected I" through a pipe 66 with the stationary governor chamber 65 and also with the air entrancepassage 54. Chamber 33 is below the diaphragm 46 and is connected through the pipe iii! to the inside of the rotating element 28 o the governor.

A centrifugally controlled weight 25 carries a needle valve 3% and is retained by a tension spring 26. The sha t 22 is driven by a bevel wheel I22 which is driven by a small bevel wheel 1-24 which is driven by a gas turbine 9% which drivesa supercharger 80.

An exhaust throttle 5. 3, when open, diverts'the flow of exhaust from the exhaust passage 94 away from the gas turbine 96 and out through the main exhaust pipe 92. The throttle 48, when opened, allows about 90% of the exhaust gas to escapethrough passage 92, the which flows through 94 rotates wheel 98 and blower 913 without appreciably raising the pressure in the inlet passage Ell. When the exhaust throttle 48 is 2 closed the exhaust flows through the exhaust Passengers an turbin 6 A herm stat I26 control a ta ered needle valve 41 which regulates the pressure the cha be 3 As ice .42 c os h ro t e 148 whi h is opened by th spring .4 c ne ted t h lever is. Qh rgti t When the engine is first started the thermostat l'26 adjusts the needle 41 so as to restrict the chamber 38 from communicating with the atmosphere. When the engine is started the thermostat [26 is cold. and raises the needle valve 4? and closes the passage connecting the chamber 38 with the atmosphere. After the throttle I8 is first opened wide the stop 14 engages with lever 18 and the continued movement of the rod 12 moves the lever 78 and stretches the spring 84 and takes the load off the pin N32. The throttle fill is then closed by the spring 42 and remains closed as the speed of the engine increases. The exhaust gases then rotate the gas turbine 96 and the supercharger 94) which pushes air into the inlet passage 54 in a well known manner.

The speed of the rotating elements of the governor 222A2628 increases and the governor controlled valve 31! moves so as to restrict the connection between the pipe l2!) andthe inside of the stationary governor casing 65 and the pipe 66. The pressure-in chamber 38 falls, anl eventually falls to the pressure of the atmosphere and the throttle 48 opens under the influence of the pressure in pipe in' the chamber 60.

The amount of the movement o the throttle valve 45 and its timing are determined by the relative shape and position of the two valves 30 and 41. The hotter the engine the more the valve M is open and the lower is the speed at which the movement of the valve 30 is effective to start to close the exhaust throttle it. The hotter the atmosphere and the longer the engine has been running the more the va ve 4! opens and the quicker the exhaust throttle 48 opens, hence the sooner the exhaust pressure is allowed to escape through the passage 92' the less ,is the amount of supercharge and the lower is the governed speed.

The danger of burning the gas turbineeli is less as the throttle 48 movesawayrfrom itsclosed position towards its wide .open position which is the positionsh-own on the drawing.

The thermostat H5 is also responsive to the airblQwing over the ,enginc by the cooling fan of the radiator. Hence the thermostat is responsive to the circumambient temperature under the hood covering the engine.

With normal operation, that is when the turbine revolves below its governed speed, the valve 30 is drawn to the right by its tension spring 26. When this happens the valve 30 opens and the restrictions shown in the valve 30, to the right of the tapered end, become the controlling restrictions between the two pipes 66 and I20. During this normal low speed operation the thermostat I26, when cold, raises the valve 41 high enough so that the pressure in chamber 38 builds up through these two restrictions in valve 30 to be almost equal to the pressure in chamber 60. The compression spring 42 then acts to rotate the valve 48 clockwise whenever, after the throttle I8 has been opened, the continued movement of the control rod I2 (stretching the spring 84) calls for more power. When, as a result of the above operation, the valve 48 approaches its closed position more and more of the exhaust gases are forced through the turbine wheel 96 which drives the blower 98 so as to build up pressure on both sides of the wall 46 and in the inlet manifold I6.

If the engine is permitted to run for any long period of time the exhaust passages 92 and 94 become red hot especially in hot weather and heat is radiated over element I26.

The thermostatic element I26 then opens the valve 41 and thus the pressure in chamber 38 is allowed to escape to the atmosphere. The pressures on both sides of the moving wall 46 then become unbalanced and the moving wall descends compressing the compression spring 42. The escape valve 48 is thus turned counterclockwise by the lever 80 towards its wide open position (the position in which it is shown).

If the speed of the turbine continues to rise to exceed a critical speed before the valve 48 is opened wide by the thermostat I26, the valve 30 restricts the connection between the passages 68 and I 20. This is the equivalent of openin the valve 4! in response to an increase in temperature. In that event any compression pressure higher than that balanced by spring 42 will tend to open the valve at any temperature. The net result of the temperature responsive valve 4'! and the turbine speed responsive valve 30 is that the valve 48 opens at a lower temperature when the speed of the turbine is high and at higher temperatures when the speed of the turbine is below its governed (critical) speed.

The engine is thus protected against being overloaded for too long a period of time at its maximum torque in hot weather and the turbine is protected in all weathers against being run at dan erous speeds.

Under any specific conditions the thermostatically controlled valve 4'! tends to hold the temperature of the exhaust assa es 92 constant because after the valve 48 opens nearlv all the exhaust flows ast the point at which the bimetal I26 is sup orted but less air enters the engine manifold I0. Hence the immediate effect is an increase in temperature of the element I26 and the final result is a reduction in temperature so that eventually the exhaust escape valve 48 is held in an intermediate position by the thermostatically controlled valve 4! depending on the temperature of the air surrounding the bimetal element I96 and on the period of time the en ine has been run at maximum power with throttle I8 wide open. The result s that a t r the s ercharger goes into operation it operates only at 4 speeds modified by the operating temperature and it is protected against prolonged running developing its maximum air delivery and resulting in excessive heat conditions.

What I claim is:

1. A control for a truck engine having an exhaust driven turbine, a supercharger for said engine driven by said turbine, a throttle controlled air and fuel entrance to said engine, manually and automatically controlled means for said turbine comprising a centrifugal governor driven by the gas turbine, an exhaust pipe leading to the turbine, an escape valve therein responsive to the centrifugal governor so as to open at high speed to render the gas turbine less effective by permitting the exhaust gases to escape without rotating the gas turbine, manual control means for opening the throttle including an overtravel beyond the point of wide open throttle, yieldable means for holding the escape valve open, manually controlled means for neutralizing the said yieldable means after the throttle valve has been opened during the said overtravel portion of the manual control means, an additional control for the escape valve responsive to temperature including a thermostat mounted adjacent the exhaust pipe, servo-mechanism connected to said escape valve for opening and closing said valve, a servo-valve therefor controlled by said thermostat and adapted at temperatures beyond a predetermined temperature to cause the escape valve to open.

2. A control for an internal combustion engine having an exhaust turbine and having super.- charger driven by said turbine, and in which there is an exhaust pipe leading to said turbine, an escape passage for said exhaust, a valve in said escape passage, a yieldable means connected to said valve so as to ultimately close said valve, temperature responsive means exposed to the heat radiated by said exhaust pipe including a themostat mounted adjacent the exhaust pipe, servo-mechanism operatively connected to said escape valve, a servo-valve therefor controlled by said thermostat and adapted at temperatures higher than a predetermined temperature to cause the escape valve to open.

3. A control as claimed in claim 2 in which the means to counteract the eifect of said yieldable means comprises a chamber, a movable wall dividing said chamber into two chambers and connected to said escape valve in said escape passage from said exhaust pipe, a first passage connecting one of said two chambers to the atmosphere, a valve in said first passage connected to said temperature responsive means so as to be opened by said temperature responsive means with high temperature, a second passage connecting said chamber to the supercharger pressure, a restriction in said second passage, a third passage connecting the chamber on the other side of the movable wall to the unrestricted eifect of the supercharger pressure, the movable wall being so connected to the escape valve that the supercharger pressure tends to open the escape valve when the temperature responsive valve is opened with increasing temperature by overcoming the yieldable means which tend to close the escape valve with decreasing temperature.

A manual and pressure ponsive control means for an internal combustion engine including an exhaust driven turbine, a supercharger 9 ine driven by said turbine, means for llmliflng the pressure derived from said exhaust turbme dnven percharger associated with said internal combustion engine comprising a chamber at the pressure generated at the outlet from said supercharger. an escape passage forming a bypass around said exhaust turbine, an escape valve in said escape passage, yieldable means connected to said escape valve so as to close said valve, an air chamber, a movable wall forming one wall of said chamber and connected to said escape valve, a passage connecting this chamber with the chamber at said supercharger pressure, a restricted passage admitting atmospheric pressure to act on the other side of said movable wall which wall is so connected to the escape valve that the valve is moved towards its open position in response to any excessive rise in supercharger pressure, throttling means for the air and fuel supply to said internal combustion engine, manually operated means for controlling the throttling means including an overtravel beyond the point of wide open throttle, a loose lever mounted on said escape valve, said manually operated means during said overtravel being adapted to engage said loose lever to permit the escape valve to respond to said movable wall, said loose lever being adapted to engage said escape valve whenever the manually operated means are moved to the position in which the throttle restricts the flow of fuel and air.

5. Temperature and pressure responsive control means for limiting the power developed by an internal combustion engine having an exhaust turbine and a supercharger driven by said exhaust turbine, an exhaust escape passage comprising an escape valve therein, yieldable means connected to said escape valve and'tending to close said valve, an air chamber, a movable wall forming one wall of said chamber and connected to said escape valve, a passage connecting this chamber with the supercharger pressure, a restricted passage admitting atmospheric pressure to act on the other side of said movable wall, which wall is so connected to the escape valve that the valve is moved towards its open position in response to any excessive rise in supercharger pressure, temperature responsive means located so as to be subjected to the heat radiated from the exhaust connections of the exhaust turbine, a valve controlled by said temperature responsive means admitting atmospheric air to act on the other side of said movable wall.

6. Temperature and pressure responsive means for limiting the power developed by an internal combustion engine having an exhaust outlet, an

exhaust driven turbine therein, a supercharger for said engine driven by said turbine, an exhaust escape passage, an escape valve therein, a movable wall connected to said valve, a first chamber located on one side of said movable wall, a sec ond chamber located on the other side of said movable wall, an open first passage connecting the first chamber to the chamber at supercharger pressure, a second passage connecting the second chamber to the atmosphere, a third passage connecting the second chamber to the supercharger pressure, a restriction in said third passage, a centrifugal governor driven by said gas turbine, a governor valve controlled thereby adapted to further restrict the admission of supercharged air when the speed of the supercharger exceeds a predetermined value to the third passage leading to the second chamber to modify the eilect of the opening leading to the atmosphere, a valve in said second passage leading from said second chamber to the atmosphere, temperature responsive means adapted to move said valve to the open position at high temperatures radiated from the exhaust pipe and thereby establish a lower pressure in said second chamber and thus permit the movable wall to move in response to a lower supercharger pressure and to open the exhaust so as to allow the exhaust gases to escape at substantially lower turbine speed than would be the case at lower temperatures, yieldable means engaging with said movable wall so as to close the said exhaust valve when the pressures on both sides of said movable Wall are equal.

7. A device as claimed in claim 6 in which there are yieldable means for holding the exhaust valve open, manually controlled means for neutralizing the said yieldable means after the carburetor throttle has been opened.

STANLEY M. UDALE'.

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

UNITED STATES" PATENTS Number Name Date 2,297,235 Miiller Sept. 29, 1942 2,373,139 Morris Apr. 10, 1945 2,376,143 Edwards et al. May 15, 1945 2,376,199 Shoults May 15, 1945 2,423,417 Stokes et a1. July 1, 1947 2,453,650 Alexanderson Nov. 9, 1948

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