US2781751A

US2781751A - Governor compensator

Info

Publication number: US2781751A
Application number: US477841A
Authority: US
Inventors: Walter E Benjamin
Original assignee: PIERCE GOVERNOR CO Inc
Current assignee: PIERCE GOVERNOR CO Inc
Priority date: 1954-12-27
Filing date: 1954-12-27
Publication date: 1957-02-19
Anticipated expiration: 1974-02-19

Description

Feb. 19, 1957 w. E. ENJAMIN GOVERNOR coMPENsAToR Filed nec. 27, 1954 .Hmlll Unite GOVERNOR COMPENSATOR Application December 27, 1954, Serial No. 477,841

9 Claims. (Cl. 12S-103) This invention relates generally to speed controlling governors for internal combustion engines, and more particularly it relates to a governor compensator adapted to so control a governorrthat full load engine speed and no load engine speed will be substantially equal to one another.

The conventional centrifugal governor has the inherent characteristic that it so controls an internal combustion engine that the full load speed of the engine is slightly below the no load or idling speed. For example, a governor may be set to provide a no load speed of 1800 R. P. M., but when full load is impressed on the engine, the engine speed will be found to be 1700 R. P. M., for example. This is caused by the fact that the weights of the governor acting against the force of a restraining spring do not create a force at full load which is exactly identical to the force created at no load. For example, if the weight force at 1700 R. P. M. full load is thirty-two inch pounds, it is found that the weight force at full load to maintain i800 R. P. M. must be 35.9 inch pounds or 18/ 17 squared times 32 where no load speed is 1800 R. P. M. and uncompensated full load speed is 1700 R. P. M.

Accordingly, the principal object of this invention is to provide a compensating device for centrifugal governors which will be elective to control a governor so that full load speed of an engine will be identical with no load speed of said engine.

Another object of this invention is to provide a compensating device for centrifugal governors which may be coupled to a centrifugal governor and to the carburetor for. increasing the force applied to the throttle at full load as compared to that applied at no load.

Still another object of this invention is to provide a compensator of the character set forth in the preceding objects wherein there is provided valve meansadapted to control the rate of movement of the compensator to prevent overrunning of a pre-set engine speed when the loadon the engine increases or decreases.

Inaccordance with this invention there is provided a compensator for centrifugal governors which may be connected to a carburetor, valve means in said compensator for controlling the rate of movement of said compensator when the load on an engine increases, thereby to prevent overrunning of the pre-set engine speed with increased load thereon, and a second valve means adapted to control reverse movement of said compensator when the engine load decreases, thereby to prevent overrun of engine speed during decreasing load on the engine.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

Fig. l is a schematic diagram, partially in cross section, of a compensator and governor system as provided in accordance with this invention.

Fig. 2 is a graph illustrating the forces exerted by the governor weights at no load and full load on a typical internal combustion engine.

Patented Feb. 19, 1957 Referring to the drawings, there is provided a conventional centrifugal governor 10 having yball weights which may be rotated by a gear 11 driven from a controlled internal combustion engine (not shown). The weights actuate a throttle actuating lever 14 having a biasing spring 15 connected to an adjustable tensioning member 12 and a bolt member 16 fixed to the lever 14 or to the shaft on which the lever 14 may be flxedly mounted. Lever 14 may be connected by means of a control rod 18 to a fuel flow controlling valve 19 pivotally mounted in the portion 20 of a conventional carburetor (not shown). In accordance with conventional practice there is provided within the portion 20 a venturi 21.

The compensator 23 consists of a casing member 24 within which is supported a bellows 25, the casing and bellows being supported on a valve member 27 as illustrated in Fig. 1. The valve member 27 may be supported on a bracket 28 attached to a convenient portion of the engine or the carburetor, and the Valve is connected to the venturi 21 by means of a tube 30, the compensator end of which may be sealed to valve 27 by means of a conventional sealing device 31.

Valve 27 comprises a passage 32 into which tube 30 opens. For controlling the flow of air from the bellows into tube 30 and venturi 21 there is provided a needle valve 33 which is threaded to valve 27 and seats within the inner end of a passage 34. The outer end of passage 34 communicates with the interior of bellows 25. A spring 36 may be interposed between the head of needle valve 33 and the outer surface of valve 27 for holding needle valve 33 in adjustment in accordance with conventional practice.

For controlling the flow of air from venturi 21 through tube 30 and into the bellows 25, there is provided a disc valve 38 which may be spring loaded by means of a spring 39, one end of which bears on disc 38, and the other end of which may be xed in any suitable manner to the valve 27 as at 37.

The bellows 25 may be coupled to lever 14 by means of a block 40 xed to the end of bellows 25 and into which may be threaded a rod 41. Rod 41 in turn may be pivotally attached to an adjustable bolt member 42 threadedly mounted within a boss 43 mounted on the lever 14.

Referring to Fig. 2, the weight energy curve 45 may represent the relationshipl between the force of the governor weights and the R. P. M. of the governor weights when the engine speed is decreased from a maximum down to a selected minimum. If the governor is set to provide an engine speed of 1800 R. P. M. at no load, it is found experimentally that the force of the governor weights is approximately fifty-two inch pounds, as indicated by the point 46 on curve 45.

The curve 47 may represent the relationship between the force of the governor weights and the revolutions per minute of the governor weights when the engine speed is increased from zero to maximum. Therefore, the full load speed normally would be at some point below the no load speed, such as 1700 R. P. M., at which speed the force of the weights is approximately thirtytwo inch pounds, as indicated at 48. To cause a governor to produce a no load speed and a full load speed which are identical, it will be necessary to increase the force opposing the weight force on curve 47 to raise the point 48 on curve 47 to 1800 R. P. M. Thus, it will be apparent that at 1800 R. P. M. the inch pounds of force on curve 47 must be approximately 35.9 inch pounds, or 18/ 17 squared times thirty-two. Therefore, the force required to raise the speed from 1700 R. P. M. full load to 1800 R. P. M. full load is 3.9 pounds in addition to the 1700 R. P. M. force. This same theory applies at rany portion of the full load,- but the additional force 3 required will be in proportion to the engine loading. Compensator 23 provides the additional force which has been explained above.

In Operation it may be assumed that the engine is running under no load under governo'r control at a speed of 180() R. P. M. Under these conditions the governor weights will be in an outer or exploded position and producing energy about as shown on curve 45 in Fig. 2. The governor lever 14 will have moved toward the right, and the carburetor valve 19 will be partially closed. The bellows 25 will be extended a distance equal to the movement of the lower end of bolt 42 on lever 14. This extension is possible because the venturi vacuum is quite low due to the low velocity of the air traveling through the venturi 21. When a load is applied to the engine, the amount of air entering the engine is in proportion to the engine loading. The size of the combustion chamber does not change, and the size of the carburetor venturi does not change, whereby the velocity of air through the venturi will be in proportion to the air volume entering the engine and, therefore, in proportion to the engine loading. When a load is applied to the engine, the engine speed drops and the governor spring 15 starts to close the governor weights, whereby the lever 1.4 moves in a counterclockwise direction to open the valve 19 and admit more air into the engine. This causes a drop in pressure at the throat of the venturi or an increase in venturi vacuum, thereby causing the bellows 25 to start collapsing. The bellows through the rod 41 applies an additional force to that of the spring 15, thereby causing the weights to close still further. This action opens the throttle suciently to increase the engine speed to its original no load speed. Thus, compensator 23 serves to supply an `additional force of 3.9 inch pounds, which is indicated to be necessary in Fig. 2 in order to bring full load engine speed up to no load engine speed.

When the load is increased as previously described, the bellows 25 would normally respond at an excessive rate of speed, which would cause the engine speed to overrun, for example, to 1900 R. P. M. When this occurred, the governor weights would tend to move the throttle toward a closed position, whereby there would be hunting. The needle valve 33 may be adjusted to control the rate of flow of air out of the bellows to such a value that the bellows will move at a reduced rate of speed and thereby prevent overrunning by the governor and by the engine, and thereby to prevent hunting When engine load is decreased, the governor follows n reverse action to hold engine speed constant and expands the bellows 25. Again, overrunning would occur except that the discs valve 38 opens to admit air from venturi 21, thereby preventing the tendency of the engine speed to be increased to an excessive degree. lt will he evident that the disc valve 38 is necessary to bypass valve 33. Without such a bypass, the bellows could not expand at the rate required by the governor; and the governor could not respond quickly enough to increased speed, which would normally result from decreased load.

From the foregoing description it will be apparent that this invention provides a governor compensator which is eiective to provide identical no load and full load speeds in an internal combustion engine. Furthermore, the compensator provided by this invention functions to prevent overrunning by the engine when a change of load occurs.

The invention claimed is:

l. A governor system for internal combustion engines comprising a carburetor, a venturi in said carburetor, a valve in said carburetor for controlling ow of fuel and air through said venturi, a speed responsive iiyball governor including a spring loaded control lever connected to said valve for opening and closing said valve in accordance with variations of engine load to maintain a constant engine speed, and compensating means for controlling said governor to provide identical engine speeds at no load and full load, comprising a bellows connected to said venturi and responsive to venturi pressure, a rod coupling said bellows to said control lever whereby said bellows may assist the spring loading of said control lever when engine load increases, a needle valve be- Vtween said bellows and said venturi to control the rate of collapse of said bellows to prevent overrunning of a predetermined engine speed when the load on said engine increases, and a spring loaded disc valve by-passing said needle valve for admitting air to said bellows when engine load decreases to prevent overrunning oi said preset engine speed.

Z. A governor system for internal combustion engines comprising a carburetor, a venturi in said carburetor, a valve in said carburetor for controlling flow of fuel and air through said venturi, a speed responsive flyball governor including a spring loaded control lever connected to :said valve for opening and closing said valve in accordance with variations of engine lload to maintain a constant engine speed, and compensating means for controlling said governor to provide identical engine speeds at no load and full load, comprising a bellows connected to said venturi and responsive to venturi pressure, a rod coupling said bellows to said control lever whereby said bellows may assist the spring loading of said control lever when engine load increases, a first valve between said bellows and said venturi to control the rate of collapse of said bellows to prevent overrunning of a predetermined engine speed when the load on said engine increases, and a check valve lay-passing said first valve for admitting air to said bellows when engine load decreases to prevent overrunning Yof said pre-set engine speed.

3. A governor system for internal combustion engines comprising a carburetor, a valve in said carburetor for controlling flow of fuel and air, a speed responsive governor connected to said valve for opening and closing said valve in accordance with variations of engine load to maintain a constant engine speed, and compensating means for controlling said governor to provide identical engine speeds at no load l'and full load, comprising a bellows connected to said carburetor and responsive to pressure therein, a rod coupling said bellows to said governor whereby said bellows may apply aiding force to said governor when engine load increases, a rst valve between said bellows and said carburetor to control the rate of collapse of said bellows to prevent overrunning of a predetermined engine speed when the load on said engine increases, and a check valve by-passing said rst valve for admitting air to said bellows when engine load decreases to prevent overrunning of said pre-set engine speed.

4. In a governor system for internal combustion engines comprising a carburetor, a venturi in said carburetor, a valve in said carburetor for controlling flow of fuel and air through said venturi, and a speed responsive tlyball governor including a spring loaded control lever connected lto said valve for opening and closing said valve in accordance with variations of engine load to maintain a constant engine speed, a compensating means for controlling said governor to provide identical engine speeds at no load and full load, comprising a bellows connected to said venturi and responsive to venturi pressure, a rod coupling said bellows to said control lever whereby said bellows may assist the spring loading of said control lever when engine load increases, a needle valve between said bellows and said venturi to control the rate of collapse of said bellows to prevent overrunning of a predetermined engine speed when the load on said engine increases, and a spring loaded disc valve by-passing said needle valve for admitting air to said bellows when engine load decreases to prevent overrunning of said pre-set engine speed.

5. In a governor system for `internal combustion engines comprising a carburetor, for controlling tlow of fuel and air, and a speed responsive governor' including a spring loaded control lever connected to said carburetor for controlling said carburetor in accordance with variations of engine load to maintain a constant engine speed, a compensating means for controlling said governor to provide identical engine speeds at no load and full load, comprising means responsive to pressure in said carburetor for assisting the spring loading of said control lever when engine load increases, a needle valve between said means and said venturi to control the rate of decrease of said spring loading to prevent overrunning of a predetermined engine speed when the load on said engine increases, and ya check valve by-passing said needle valve for admitting air to said means when engine load decreases t-o prevent overrunning of said pre-set engine speed.

6. A governor system for internal combustion engines, comprising a carburetor, a valve in said carburetor for controlling flow of fuel and air, a speed-responsive governor connected to said valve for opening and closing said valve in accordance with variations of engine load to maintain a constant engine speed, a compensating means for controlling said governor to provide identical engine speeds at no load and full load, comprisin-g means responsive to pressure in said carburetor for applying assisting force to said governor when engine load changes, a first valve means between said pressure-responsive means and said carburetor to control the rate of movement of said pressure-responsive means to prevent over-running of la predetermined engine speed when the load on said engine increases, and a second valve means controlling said pressure-responsive means for accelerating response of said pressure-responsive means when engine load decreases to prevent over-running of said pre-set engine speed.

7. A governor system for internal combustion engines, comprising la carburetor, a valve in said carburetor for controlling ow of fuel and air, a speed-responsive governor connected to said valve for opening and closing said valve in `accordance with variations of engine load to maintain a constant engine speed, a compensating means for controlling said governor to provide identical engine speeds at no load and full load, comprising means responsive to pressure in said carburetor for applying assisting force to said governor when engine load changes, a iirst means responsive to decrease of pressure in said carburetor for operating said pressure-responsive means at a certain rate to prevent over-running of a predetermined engine speed when the load on said engine increases, and a second means reponsive to increase of pressure in said carburetor for operating said pressure-responsive means at a h-igher rate when engine load decreases to prevent over-running of said pre-set engine speed.

8. A governor system for internal combustion engines, comprising a carburetor, a valve in said carburetor for controlling ilow of fuel and air, a speed-responsive governor connected to said valve for opening yand closing said valve in accordance with variations of engine load to maintain a constant engine speed, a compensating means for controlling said governor to provide identical engine speeds rat ne load and full load, comprising means responsive to pressure in said carburetor for applying controlling force to said governor when engine load changes, a rst means for controlling the rate of application of assisting f' force to said governor by said pressure-responsive means to prevent over-running of a predetermined engine speed when the load on said engine increases, a second means controlling said pressure-responsive means and operative to decrease the impedin-g force of said pressure-responsive means when engine load decreases to prevent over-running of said pre-set engine speed.

9. A governor system for internal combustion engines, comprising a carburetor, a valve in said carburetor for controlling flow of fuel and air, a speed-responsive governor connected to said valve for opening and closing said valve in accordance with variations of engine load to maintain a constant engine speed, a compensating means for controlling said governor to provide identical engine speeds at no load and full load, comprising means responsive to pressure in said carburetor for applying assisting force to said governor when engine load increases, a first means to control the rate of application of force by said pressure-responsive means to prevent over-running of a predetermined engine speed when the load on said engine increases, and a second means controlling said pressureresponsive means to permit relatively free operation of said governor When engine load decreases to prevent overrunning of said pre-set engine speed. y

References Cited in the file of this patent UNITED STATES PATENTS 2,138,100 Howard Nov. 29, 1938 2,221,201 Pope et al Nov. l2, 1940 2,328,452 Hobart Aug. 3l, 1943 2,363,887 Mallory Nov. 28, 1944 2,368,822 Gardner Feb. 6, 1945