US2364115A - Governor control for prime movers - Google Patents

Description

Dec. 5, 1944. J, wHlTEH'EAp 2,364,115

GOVERNOR CONTROL FOR PRIME MovERs Filed Jan. 1,1945

Patented bec. 5, 1944 UNITED STATES 4PArlarslT v oFFlcl-z GOVERNOR CONTROL FOR IYRIME MOVERS Willard J. Whitehead, Rockford, lll., assigjnor to Woodward Governor Co a corporation of Illinois mpany, Rockford, lll.,

Application January 1, 194s, serial No. 471,005

' 7 claims. (o1. 2641-7) -This invention relatesA to the speed control of prime movers, and the general object is to pro-l vide a novel mechanism'for detecting abnormal loading of the prime mover and limiting the energy supply therefor to a predetermined value for the existing speed.

Another object is to associate the limiting A laterally through thesleeve I1 and communicat' mechanism with a governor control inta novel manner such as to permit ofnormal functioning of the governor compensating mechanism.

The invention also resides in the novel mannerofdetecting abnormal loading and of limiting the energy supply. y

. Other object'sand advantages of the invention will become apparent from the following detailed description taken inconne'ction with the accompanying drawing, in which Figure 1 is 'a schematic View of a governor control embodying the novel features of the pres ent invention. A

. Figs. 2 and 3 are sections taken along the lines 2-2 and 3 3 Of Fig. 1. h

in amain hydraulic governor which operates automatically in response to changes in the speed of a. prime mover (not shown) to adjust a rod 2 connected to a fuel pump, gas mixing valve,

steam throttle or other device for controlling the supplyof an energy medium to the prime mover. The governor is mounted on the engine and includes a pair of flyballs 3 pivoted at 4on a head 5 which is housed in a, casing 6 and isfast on the upper end of a hollowvertical shaft 1 The latter is journaled in a body 8 and is driven by the prime mover through a couplingll.

The inwardly projecting' arms lIll of the iiyner race of the bearing II is connected tothe stem I5 of a plunger lli-of a pilot valve which is slidable within a sleeve I1 that rotates with the drive sleeve 1.

The plunger I 5 coacts with a port Ill'opening ing continuously with apassage I9 that leads to a hydraulic servo motor comprising a cylinder and apiston 2| slidable therein above the passage I9. This piston is on the throttle actuating rod. 2 and is urged in the throttle-closing vdirection 'by a spring 22 acting in compression between the closed end of the servo cylinder cap 23 and a cap 24 on the piston.

Oil lling a sump -25 in the valve body 8 is drawn through a passage (not shown) to the inlet of a gear pump 25 having one gear rotatable with the shaft 1. The pump discharges through l'that the accumulators deliver oil at a predetervertical passages 21 within the valve bodv and into passages 28 leading to the upper ends of accumulator cylinders 29 having pistons 3l therein andadapted to overflow through passages The -pistons are loaded by springs 3l so mined pressure to the upper end of the sleeve 1, the ow being through passages 32, an annular recess 33 around the drive shaft, and ports 34 and 35 in the sleeves 'I and I'I. Thus, as the engine speed decreases below a value predetermined by the speeder spring setting, the plunger I6 is lowered below the port I8 and pressure iluid will be admitted to thecylinder 20 so as to raise I `-the servo piston 2| and therefore increase the engine throttle opening. Conversely, in response to a speed increase, the plunger I6 is raised .thereby connecting the cylinder 20 to the sump 35 through the Iport I8 and sleeve ports 36 and 3l. Fluid is thus permitted to drain from the cylinder 20 allowing the spring 22 to move the rod 2-downwardly and decrease the supply of energy medium to the prime mover.

To obtain isochronous operation of the engine,

the governor incorporates a stabilizing mechball bear upwardly against the outer raceV of a ball bearing II whose inner race is urged downwardly by a, compression spring I2. The force f this spring determines the engine speed Which is maintained by the governor and may be adjl'lsted by manuallyturning a segment l3/geared to a sleeve I4. The latter is slidable in across member I3a and receives the upper end of the spring which bears against a plug I 4a. 'I'he inanism of well known construction. Herein, this includesa receiving piston 38 slidable in a cylinder 39 in the drive sleeve I and connected to the lower end of the valve sleeve I 1. The cylinder communicates' through a port 40 and a passage 4I with a cylinder 42 having therein a transmitting piston 43 which is fast on the throttle 'rod 2. 'Through orices `III, the passage 45 communicates with the sump 25 so that oil may flow into or out, of the compensating passage depending on pressure conditions. The rate of such flow is controlled by the setting of needle valves 45 and the spring force on the piston 38 which is urged toward a centered position by a spring 46 compressib-le from either end.

Permanent speed droop may be provided for by adjustment of the speeder spring stress independently of the segment I3 and in accordance withl the movements of the servo piston 2 I. Herein this is accomplished by a lever 48 fulcrumed at 49 on the sleeve I4 and bearing downwardly at 50 on the plug Illa. The free end of the lever is pivotally connected at to the upper end of a rod 52 which normally moves with the servo piston 2| and is slidable in the cap 23. For any given setting of the segment |3 the position of the fulcrum 49 is xed so that as the servo piston 2| moves in response to a speed change, the rod vision is made for limiting the movement of the throttle rod 2 in the speed increasing direction whenever the prime mover becomes overloaded while operating below a preselected speed. For this purpose, the connection between the rod 52 and the servo p-iston 2| includes a valve 55 which is normally closed by a spring 56 and which when opened permits iiuid below the piston 2| in the servo cylinder 20 to be br-passed through passages 5T in the piston 2|, a chamber 58 in the piston cap 24, the valve 55, ports 59 and a passage 60 leading to the sump 25. The valve comprises a conical member 6| on the lower end of the rod 52 which is slidable inthe cap in' the direction of the servo motion. The spring 56 acts in comp-ression against a shoulder on the rod to, urge the valve member 6I upwardly against a downwardly facing seatthereby normally maintaining the valve closed as itmoves up and down with the servo piston. If the rod 52 is blocked during upward or throttle opening motion of the servo piston, the spring 56 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. I

Such blocking of the valve rod is effected in the present instance by a stop surface 62 on a bar 63 which is slidable transversely of the rod 52 in the path of a roller 64 on the rod. When the bar 53 is retracted to the position shown, a cut away portion of the bar is disposed opposite the roller B4, and the rod is not blockedv during the normal movements of the servo piston, .the valve 55 remaining closed. If the bar is shifted to the left to bring the stop surface 52 opposite the roller 64, upward movement of the rod 52 is limited with the l"esult .that the Valve 55 will become opened in the further movement of the piston 2| thereby by-passing oil from the servo cylinder to then limit the servo and fuel rod movement.

Means is provided for measuring the speed of the prime mover and positioning the stop surface 62 so that it will become eiective to limit the throttle opening at a selectedspeed. Herein this means comprises a poweractuated servo operator controlled by an auxiliary governor or a centrifugal device having a large speed droop. As shown,

justable restriction i5a therein.' A second port lt leads to the head -endA of a cylinder 'I8 through 52 moves the lever 48 about the fulcrurn 49. The

this auxiliary governor includes flyballs 61 piva passage T1. The flow of oil to the vcylinder' through the passage`11 or from the cylinder to the sump 25 through a sleeve passage '19 is controlled by a valve member or plunger 8B carried by a stem 8| which slides vertically in the sleeve 10 and is urged downwardly by a compression spring 82. The latter bears against the inner race of a ball bearing 83 while the arms 84 of the flyballs bear upwardly against the outer race.

The cylinder 18 is disposed above the fiyballs 61 and extend. perpendicular to the rotational axis thereof. A piston 85 slides in the cylinder and carries the stop bar 63. To provide for axial and also vertical adjustment of the bar,

the latter is clamped by screws 63a and a block 63b in a seat on the end of the piston S5. Springs 86 disposed Within the piston act in compression between a plug 81 and shoulders 88 and 89 tov urge the piston to the right against the pressure maintained in the head end of the cylinder. provide a large speed droop, usually vabout fty percent, the Speeder spring 82 of the auxiliary is loaded variably `in accordance with changes in the position of the piston 85. For this purpose, the upper end ofthe spring 82 bears againstv a plug 96 slidable axially in the body 8| of the cylinder and carrying a roller 92 which is held by the spring 32 in contact with a cam surface 93 cut along the exterior of the piston.

Under normalgload conditions, the parts of the limit control will be positioned as shown, the piston 85 having assumed a position determined by the speed at which the governor is running, in this case near the upper endV ofthe speed range. force of the spring 82 will move the fly-weights -6l inwardly lowering the plunger 8U to admit high pressure oil to the cylinder 18 at arate determined by the adjustment of the metering orice 15a. The piston 85 is thus movedto the'left and continues to move until the roller 92 rises sufficiently, as permitted by the moved cam surface 93, to reduce the spring load to a value at which the flyballs will return to centered position'an-d close olf the port 16. In response to a speed increase, the flyballs move out lifting the pilot valve and allowing oil to drain from the cylinder 'i8 until, in the ensuing movement of the piston 85 to the right, the spring 82 is loaded sufficiently to center the fiyballs and again close the port 16. The surface 83 is curved so that the relationship between the `engine speed and the movementof the piston `85 is essentially a straight line.

By thus moving the stop surface 62 in accordance with speed changes and locating the surface so that it will block the rod 52 at'a predee termined positionl in response to an increase in throttle opening, provision is made for automatically limiting the amount of fuel capable of being delivered at a given speed. Thus, when vthe engine is running' at the maximum predetermined load for a given speed the roller 54 is in contact with thecam surface 62 but the valve 55 is closed. If the torque requirement increases so that the engine speed falls as a result' of the increased load, the port I3 will be opened, admitting oil to the servo cylinder 26. Since the roller 64 is at this time against the .cam surface 62, the valve 55 will be opened as tle piston 2| is moved up' wardly, thus by-passing oil admitted to ,the cylinder 20 andV preventing further upward movement of the piston. The admission of more'fuel-to the If now the engine speed decreases, the

engine being thus prevented, the speed of the engine cannot be restored to normales long as the excessive torque requirement exists and the auxiliary governor will still further reduce the amount of fuel supplied to the engine by admitting oil to the cylinder 18, forcing the piston 85 to the left and the rod 52 downwardly thereby opening the valve 55 further and permitting the spring 22 to force thepiston 2| down until the valve 55 is by-passing all of the oil supplied to the servo cylinder. VIt will be seen, therefore, that the engine speed will be reduced until the torque requirement balances the torque output of the engine with the amount of fuel permitted by the auxiliary governor. It will be obvious that unless the torque is reduced by' the nature of the connected load, the engine will be overloaded further as the speed is reduced and the speed will ultimately be reduced to zero. 4 If, however, the torque requirement reduces with the speed, as in a marine propulsion installation, a -balance b'etween the torque requirements and the torque output as limited by the speed of the engine may be reached. Also, if the torque is reduced manually by some external means to a point equal to that determined by vthey maximum position of the'rod 2 for a given speed, a state of equilibrium will'once more exist. As soon as the torque re'- quirement is reduced to avalue below that established by the limiting governor, the engine speed will rise and the valve 80 will permit the discharge of oil from thel cylinder '18, allowing the springs 8B' to force the `piston 85 to the right and permitting the roller 64 to move up the slope of the cam surface 62. This allows the valve 55 toclose and the piston 2| to move upwardly as long as the valve I6 is below the port i8 as a result of an engine speed lower than thatl established by the setting of the segment I 3. Upward movement of the piston 2l will continue until the V engine speed is again restored to normal since, as a result of the increase in enginetspeed the piston 85 is movin-g still further to the right, keeping the valve 55 closed against oil in th'e cylinder 20.

It will be observed from the foregoing that the sponsive device driven in unison with said governor, a hydraulic operator, an element moved thereby in proportion to detected speed changes,

land means carried by said element and operable speed responsive means including a valve controlling the admission 'of pressurefluid to .said

cylinder, a device movable into and out of blocking position with respect to said'member, and auxiliary speedresponsive means for moving said device into blocking position in response to a predetermined decrease in speed.

3. A governor mechanism comprising, in combination, alcylinder, a piston therein having a by-passage therethrough, speed responsive means including a fluid control valve controlling the torque limiting control including the auxiliary high speed droop 'governor and the means for limiting the main servo motion operates indepndently ofA the main governor and therefore does not in any Way interfere with the normal functioning of the latter until control of the fuel supply is taken away from the main governor upon the occurrence of an overload for that particular speed. 'Thus, the desiredcompensating action may be obtained as well as permanentspeed droop. Moreover, by employing a power actuator for the cam bar 63, the latter may be moved to permit either an increase or a decrease in engine torque as engine speed decreases, al-` though in the arrangement shown, a decreasev in torque is required with a decreasein speed.

admission of pressure fluid to said cylinder on one side of said piston, a rod carried by said piston and movable axially relative thereto, a second valve controlling said by-passage 'and having an element continuously movable with said piston, spring means urging said element toward closed position, and a stop member mounted for movement into and out of active position to block the -rod and cause opening Vof said valve at a predetermined point in the travel of s aid piston..

4. A governor having, in combination, a servo motor comprising a cylinder and a piston movable therein, a speed responsive valve controlling vthe flow of pressure iluid into said' cylinder on one side of said piston to cause movement of the latter in one direction, a spring closed valve carried by said piston and having a member movable relative to the piston in the opposite direction to open the valve and permit the 4escape of uid from said cylinder independently of said speed responsive valve, and normally inactive means adapted to be rendered operative selectively to block the advance of said valve member at a predetermined point and cause opening of the valve in the further movement of said piston.

5. A governor mechanism comprising a fluid servo having a movable lactuated element, a main valve governing the ow ,of pressure fluid to said servo, speed responsive means actuating said The cam 62 may of course be shaped in various ways and positioned to Vbecome eiective at any desired speed thereby producing a limiting action of the desired character.

I claim as my invention: y 1. The combination of a regulating member, a

-hydraulic servo actuator therefor, a speed responsive governor including a valve controlling the admission of vpressure fluid to saidactuator, a normally closed valve having an actuating member movable with said regulating member and adapted when blocked to open said valve and divert the pressure fluid, a second speed revalve to vary the iluid pressure in said servo and thereby change the position of saidelement', an

auxiliary valve adapted when open to reduce the fluid pressure in said servo irrespective of the condition of said main valve, `means urging said auxiliary valve to closed position during normal movements of said servo element, an abutment movable into and out of an active position, and means engageable with saidabutment as thev servo element reaches a predetermined position while the abutment is in said active position and operable in response to movement of the servo` element beyond said predetermined position during such engagement to open said auxiliary valve, the auxiliary valve remaining closed as the servo element moves to said predetermined positionV while saidy abutment is in said inactive position. 6.' A governor having, in combinatiom'a servo motor comprising a cylinder and a piston movable therein, a speed responsive valve controlling v the flow of pressure iluid into said cylinder on' one side of said piston to cause movement of the latter in one direction', a spring closed valve carried by said piston and having a member movable relative to the piston in the opposite direction to open the valvef and permit the escape of fluid from said cylinder independently of said v speed responsive valve, and normally inactive means adapted to be rendered operative selectively to block the advance of said valve member at a predetermined point and cause opening of the valve in the further movement of said piston,

said last mentioned means including a stop element guided for 'rectilinear movement back and forth in a path extending transversely of and substantially normal to the path of movement of said valve member.

7. A governor mechanism having, in combination, a fluid servo, a main valve governing the ow of pressure fluid to said servo, means responsive to detect speed changes toactuate said valve Aand vary the ,iiud pressure in said servo and correct for said speed deviations, an auxiliary valve adapted When open to reduce the fluid pressure in said servo, means urging said auxiliary valve to closed position, a second speed respon-

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