US2364116A - Governor control - Google Patents

Description

Dec. 5, 1944. w. J. WHITEHEAD GOVERNOR CONTROL Filed Oct. 9, 1942 ESN INVSNTO/Q., 52W/ard UQV/P/e/f'ead 7% j;

Patented Dec. 5, 1944 GOVERNOR CONTROL Willard J. Whitehead, Rockford. nl.. signor to Woodward Governor Company, a corporation of Illinois Rockford, Ill.,

Application October 9, 1942, Serial No. 461,393

to the stem 28 of a pilot valveplunger 2| which 4 Claims.

This invention relates to the control of prime movers by speed responsive governors and has more particular reference to governors of the hydraulic type- One object is to provide a governor having novel means for limiting the governor action under certain' operating conditions.

Another object is to provide a governor having a hydraulic servomotor and novel means for disabling the servomotor at selectively variable points in the movement thereof.

VA further object is to provide Aa control of the 'above character adapted to limit .the loading of the controlled prime mover during starting.

The invention also resides in' the novel character of the means for rendering the limiting device operative and inoperative and for adjusting the servo position at which the device becomes operative.

Other objects and advantages of the inventionI will become apparent from the following rdetailed description vtaken in connection with the accompanying drawing, in which Figure l is a schematic view of a prime mover and its governor control embodying the novel features of the present invention, the governor being shown in vertical central section.'

Fig. 2 is a section taken along the line 2-2 of Fig. 1. 1 t

Fig. 3 is a section .taken along the line 3-3 of Fig. 2.

In the drawing, the invention is embodied for purposes of illustration in a governor control for za Diesel type internal combustion engine 5 adapt- 'ed to be started by the admission of compressed air from a source 6 to the engine through a conduit 'l and a distributing valve (not shown) of well known construction. Such admission may be controlled by manipulation of a handle 8 to open a valve 9 in the supply line.

The throttle controlling the 4fuel supply to the engine is connected to a rod I which is adjusted automatically by a governor il mounted on the engine and including a pair of iiyballs |2 pivoted at I3 on a head |4 which is fast on the upper end of a hollow vertical shaft |6 and is housed in a casing I5. 'I'he shaft is journaled in a valve body and driven by the engine through a connection extending to the lower end of the shaft. The inwardly projecting portions I8 of the flyball arms bear against the outer race of a ball bearing I9 whose inner race is urged downwardly by a compression spring 20, the force of which determines the engine speed maintained is slidable within a sleeve 23 'that rotates with the drive sleeve I6.

The plunger 2| coacts with a port 22 opening laterally through the sleeve 23 and communicating continuously with a passage 25 that leads to a hydraulic servomotor comprising a cylinder 26 anda piston 2l slidable therein above the passage 25. 'I'he piston is on the throttle actuating rod I0 and is urged in the throttleclosing direction by a spring 29 acting in compression between the closed end of the servo cylinder cap 30 and a cap 3| on the piston.

Oil contained in a sump 32 defined by the valve body is drawn through a passage 33 (Fig. 3) to the inlet of a gear pump 34 driven from `the shaft I6. The pump discharges through a passage (not shown) into a passage 34"L (Fig. 3) leading to accumulators 35 loaded by springs 35n and delivering oil at a predetermined pressure into the upper end of the sleeve 23. The flow is through passages 36, an annular recess 31 around the sleeve I6, and ports 38 and. inthe sleeves I6 and 23. K

As the speed decreases below a predetermined value, the plunger 2| is lowered below the port 22 and pressure uid will be admitted to the cylinder 26 so as to raise the servo piston 2l and therefore increase the throttle opening. Conversely, in response to a speed decrease, the plunger 2| is raised thereby connecting the cylinder 26 to the sump 32 through the port 22 and sleeve ports 4| and 42.` Fluid is thus permitted to drain from the cylinder 26 to the sump allowing the spring 23 to move the throttle rod downwardly and decrease the fuel supply.

The governor incorporates a stabilizing mechanism of well known construction. Herein, this includes receiving piston 43 `slidable in a cylinder 44 in the drive sleeve I6 and connected to the lower end of the valve sleeve 23. The cylinder communicates through a passage 45 with a into or out of the compensating passage dependby the governor. The inner race is connected ing on pressure conditions. The rate of such ilow 1s controlled by the setting oi needle valves 49, and the piston 43 is urged toward a centered position by `spring .49a compressible from either end.

The speed setting of the governor is adjusted well known way. The shaft is journaled in the casing and carries a gear segment 5| which meshes with 'rack teeth on a tube 52 slidable in a cross-member 53. A plug 54 slidable in the tube bears at 55 against a lever 56 whose bifurcated end receives and is clamped by a screw 51 to a flattened pin 58 which is journaled in lugs 59 upstanding from the tube 52. The bifurcated other end of the lever receives a flattened pin 60 journaled in the upper end of a rod 6| which extends axially of the servo piston 21 and normally moves therewith. Through these connections, the stress in the spring 20, and therefore the speed maintained by the governor, may be varied as desired by rocking the shaft. For any given setting of the adjusting shaft 50, the position of the fulcrum pin 58 is fixed so that as the servo piston 21 moves in response to a speed change, the rod 6| moves the lever 56 about the fulcrum 58. The resulting movement of the plug 54 by the lever changes the stress of the spring 20 and produces permanent speed droop.

In accordance with the present invention, provision is made-for limiting the movement of the throttle rod l0 in one direction when certain The valve comprises a conical member 68 on the 1' lower end of the rod 6| which has an enlargement 69 slidable in the cap 3| in the direction of the servo motion. The spring 64 acts in compression against the enlargement to urge the valve member upwardly against a downwardly facing seat thereby normally maintaining the valve closed as it moves up and down with the servo piston. If the'rod 6| is blocked during upward or throttle opening motion of the servo piston, the spring 64 is overcome and the valve is opened by power supplied by the servo. This permits fluid to be by-passed thereby preventing further movement of the piston.

In the present instance. such blocking of the valve rod is effected by a stop 1l! which is mounted for movement into and out of active position longitudinally of the motion of the servo piston so that the servo position at which the stop becomes effective may be adjusted as desired. For this purpose, the stop comprises the lower end of a rod 1| slidable vertically in a fitting 12 on the governor cover. The rod carries a piston 13 which is slidable in a cylinder 14 in the fitting and is normally urged upwardly to inactive position by a compression spring 15. this motion being limited by engagement of an adjustable screw 16 on the rod with a cap 11 threaded into the upper end of the fitting 12. Downward motion of the rod to active position is limited by engagement of a collar 18 as shown with the upper end of the fitting 12, this point being adjustable by a nut 19 threading onto the upper end of the rod 1|. y

The stop is thus adapted for power actuation by the application of pressure to the upper end of the cylinder 14 through an inlet 86. In response to such pressure application, the piston 13 and the stop 10 are forced downwardly against the action of the spring to the active position shown in Fig. 1. In this position, the stop bears against one end of a lever 8| which is ful- 20`\is inactive.

crumed intermediate its ends on a pivot 82 fixed to a bracket 99 on the governor casing. Now, as rod 6I is raised during opening of the throttle by the servomotor, the upper end of the rod will engage a rounded portion 83 of the lever 8| and thus become blocked. Then, as the servo piston and the seat of the valve 63 carried thereby continue to rise, the valve is opened thereby permitting oil from the servo cylinder 26 to escape through the passages 65 and the ports 62. When the pressure on the piston 13 is relieved, the stop 10 is retracted by the spring 15 whereupon the valve 63 is closed by its spring 64 and normal conditions are restored. The valve 63 will of course also close in response to a reverse motion of the servo piston 21.

The lever 8| coacting with the valve 83 is used to limit the degree of permissible throttle opening when the stop 19 is retracted and therefore For such purpose, a screw 84 is threaded through the other end 0f the lever with its lower end adapted to contact the lever 56 at a predetermined po-int in the upward travel of the servo piston 21. The lever 8| is blocked by such engagement, the sleeve 52 being held stationary by the manually operable speed adjusting mechanism. Then, in the continued movement of the piston 21 the valve 63 is opened in the manner described above.

A governor equipped with a limit control of the character described may, for example, be used to advantage in limiting the degree of throt tle opening during starting of the Diesel engine 5 so as to prevent the delivery of more fuel than the engine Will burn with the amount of air available at low speed. This may be accomplished by connecting the inlet of the stop actuator to a branch line 85 joined to the air supply line 1 so that when starting air is admitted to the engine by opening the valve 9, the stop 10 is moved to active position automatically. Preferably, the connection is through a valve 86 by which the governor limit control may be disabled before the application of 'starting air to the engine is f discontinued. Herein, this latter valve is actuated automatically by an unstable ball head 81 driven by the engine and conditioned when the engine is operating below a predetermined speed to maintain the valve 86 open. However, when the engine attains a speed predetermined by the ball head setting, the valve plunger 88 is raised above the port 89 so as to interrupt the air supply to the limit device and release the pressure within the cylinder 14.

As a result of this arrangement, the limit stop 16 is retracted and therefore is ineffectual during normal operation. During starting, when the valve 8 is opened to admit air to the engine 5 for starting, air is also admitted through the valve 86 to the cylinder 14 and the stop 10 is forced downwardly into active position. Then, if the engine i-s running at a speed under that for which the governor is adjusted, so that the governor attempts to admit more fuel than can properly be burned at the low speed, the valve 63 is opened and the admission of more fuel is prevented. As soon as the engine attains a predetermined speed, lthe valve 86 is closed automatically and the limit control is again rendered active.

I claim as my invention:

1. The combination with a prime mover and means for temporarily supplying fluid under pressure for starting the prime mover of, a member controlling the speed of said prime mover after starting thereof by said pressure uid, a hydraulic servomotor for actuating said member, means including a fluid control valve responsive to the speed of said prime mover and controlling the iiow of pressure iiuid to and from said servomotor to correct for normal speed changes of said prime mover, a normally closed valve adapted when open to by-pass fluid from said servomotor whereby to interrupt the motion of said member independently of said control valve, al

device normally maintained inactive and adapted when in active position to cause opening of said valve as said member reaches a predetermined position, and means automatically responsive to the temporary application of pressure fluid to said prime mover during starting of the latter to move said device to said active position.

2. A governor mechanism comprising, in combination, a cylinder, a piston therein carrying a normally closed valve controlled kay-passage, a member movable with said piston and lay-passage l,and operable when blocked to open the by-paslay-passage, speed responsive means including a second valve controlling the flow of pressure fluid to and from said cylinder while said by-passage remains closed whereby to impart speed regulating movements to said piston, a vdevice movvary the extent of motion of said Vdevice-by said` second piston.

4. The combination with a prime mover and means for temporarily supplying auxiliary power for startiner the prime mover of', a member controlling the speed of said prime mover after starting thereof by said auxiliary power, a hydraulic servomotor for actuating said member, means including a fluid control valve responsive tothe speed of said prime mover and controlling the flow of pressure iluid to and from said servomotor to correct for normal speed changes of said prime mover, a normally closed valve adapted when open to 'oy-pass iiuid from said 'servomotor whereby to interruptv the motion of said member independently of said controlvalve, a device normally maintained inactive and adapted when in active position to cause opening of said valve as said member reaches a predetermined position, and means Adirectly associated with said auxiliary power supplying means and operable to move said device to active position simultaneously with the application of said auxiliary power to said prime mover, said last mentioned means acting during normal operation of the prime mover after starting thereof to hold said device in inactive position.

WILLARD J. WHITEHEAD.

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