US2324516A - Governor - Google Patents

Description

July 2o, 1943. A. KALIN 2 32 51 v GOVERNOR I Filed Sept. 10, 1941 NC Rinses vcckmses POWER. Powaa IN PUT IN PUT INVENTOR A LBERT' 'KALIN Patented July 20, 1943 UNITED STATES PATENT OFFICE GOVERNOR i Albert Kalin, Cleveland, 01110 Application September 10, 1941, Serial No. 410,283 2 Claims. 401.264-3) This application is an improvement shown but not claimed in my application Serial No. 385,228 filed March 26, 1941.

The present invention relates to an improved load limiting, speed responsive mechanism in combination with (e. g.) an isochronous governor adapted to perform regulating operations on a prime mover through the intermediary of hydraulically acting means. This indicates one object hereof.

The invention relates more specifically to mechanism in or in combination with agovernor for Diesel or other internal combustion engines in which destructive stresses occur or other undesired results obtain when fuel is fed to the engine at too higha rate at low speeds under abnormal load. Said mechanism, in other words, limits the brake-mean-effective-pressure (B. M. E. P.) in the engine cylinders when the speed of the engine drops below a predeterminable low point, indicating a further general object.

A further object is to provide a B. M. E. P. limiting means in connection with a governor Q operative to regulate speed through the inter-- mediary of a hydraulically acting servo-motor and a speed responsive element controlling a. pilot valve for the servo-motor, wherein said means and the pilot valve are always free to operate independently ot each other so faras mechanical connections between the two are concerned. A specific object is to provide a B. M. E. P.

at constant positive value. cumulator is supplied to a governor port E and pump to draw hydraulic fluid from a sump S and deliver it to an accumulator having a spring loaded plunger C and discharge vent D which cooperate to keep the pressure in the accumulator continuously therebeyond to one face F of a. double acting hydraulic servo-motor power piston G. The port'E is controlled by a lower land portion of a pilot valve plunger H which, if moved downwardly from the normal position in which shown, opens the port E a duct I leading .to the opposite (effectively larger) face J of the power piston, causing upward movement of the piston. Upward movement of the pilot valve plunger from its normal position causes an upper land portion thereof to open the duct I at a port K, dumping pressure fluid from below the power piston into the sump and causing the piston to descend-by reason of the constant pressure maintained at the piston face F.

The pilot valve plunger H is moved vertically in opposite directions as aresult of the difference between centrifugal force on a set of fly-balls L on a-ball head I rotated by the prime mover (as by shaft A and appropriate gearing concontrolling or limiting mechanism, for a governor including a pilot valve as outlined above, which mechanism becomes operative at predeterminable low speeds on part of a governed enzine tomove the valve positively in the direction to cause reduction of rate of feeding of fuel to the engine but hydraulically through the inter- 1. mediary of yieldable elastic means.

Other objects and features of the invention will become'apparent from the following description.

In the accompanying drawing Fig. 1 is a schematic or diagrammatic general assembly view of a governor incorporating a preferred general arrangement or elements embodying the invention, the governor generally being essentially the same as thatshown in the parent application and in my Patent 2,219,229 issued October 22, 1940.

Describing first the governor arrangement gen ei' l 'y. parts indicated by letters, A is a drive shaft for the governor arranged to be connected to the engine or other prime mover to be governed. the shaft driving agear pump B. The 8 P valve system and ducts arranged to enable the B is shown with a'wellknown check' nected to the ball-head) and opposing force ex erted by an adjustable speeder spring M, so that an increase in speed on part of 'the prime mover raises the pilot valve plunger and a decrease in speed lowers said plunger. Regulation of speed by' the servo-motor incident to change in load is initiated by such movement of the pilot valve plungerH.

Power input to the governed prime mover is increased by raising the power piston G (and decreased by lowering the piston) as indicated on the drawing. Thus, in governing, for example,- a Diesel engine, increase in load causes decreased centrifugal force on the fly-balls'and lowering of lation in speed or-hunting-consequent upon load change and subsequent speed-correcting. operation of the governor. The stabilizing mechanism 7 includes a hydraulic compensation systemlsupplied with fluid from the sump and actuatingand receiving compensation pistons of said system movement, of the servo-motor piston G- to damp or operating as a function'of regulating Fluid from the aceach movement of the servo-motor piston and prevent temporary overregulation of the prime mover thereby.

The actuating compensation piston N works in a trunk portion 9 of the power piston G and displaces hydraulic fluid in a duct leading to the receiving compensating piston P, slidably mounted in a cylindrical extension of the outer pilot valve element, whenever the power piston G starts to perform a regulating operation in either direction. The space above the trunk portion of the power piston is open to the sump through an upper wall portion of the power cylinder block. The motion of the receiving compensation piston P is always opposite the regulation-initiating movement of the pilot valve plunger H, and

places temporary primary yielding compensating restraint on each movement of said valve plunger through the intermediary of a coil spring Q connecting the compensating piston P and valve plunger H. The primary'compensating force is removed, after regulation is effected, by relieving the positive or negative pressure in the duct 0 through a. very small aperture in an adjustable secondary compensation leak-off needle valve R communicating the duct 0 with the sump.

As fully explained in my Patent 2,219,229, the fly-balls cause continuous rotation of the pilot valve plunger in its coacting flxed valve sleeve through contact of the ball-arm fingers with a disc portion 12. of the plunger; and the spring Q is so connected with the plunger and receiving compensation is likewise rotated in its flxed cylinder. This eliminates the possibility of binding of either the valve plunger or said piston due to foreign matter in the hydraulic fluid and assures-thatthe pilot valve is free from friction and therefore free to respond to very slight changes in speed. The spring Q also allows relative axial movement between the parts connected thereby so that the valve is always free to respond promptly to any change in centrifugal force acting on the flyballs..

In operation, when the engine load is increased the resultant decrease in speed causes relative inward movement of the -fly-balls L; lowering of the pilot valve plunger; opening of the port E; admission of hydraulic fluid through duct I to the lower side of the power piston G, and increase of fuel to the engine. The upward movement of the piston G pumps fluid through duct '0; raising the receiving compensation piston P; compressing the spring Q and exerting an upward slight force on the pilot valve plunger suflicient to offset the temporary overbalance of speeder spring force relative to the centrifugal force on the fly-balls, thus closing the port E. The port E is ordinarly closed sufllciently quickly to prevent overtravel of the power piston inthe speed correcting direction; and, as the engine returns to normal speed, the compression force of the spring Qis dissipated by reason of leakpiston P that the piston tem, and hydraulic fluid being flnally drawn from the sump into the duct 0 through the aperture of the needle valve R to relieve said tension.

Speed adjusting or changing means is represented by the speeder member U (for instance a lever) at the upper end of the speeder spring 1!. Additional speed changing means would, of course, be provided, for example as in my application Serial No. 385,228 identifled above, or in other ways as well known in the art.

The brake-mean-eifective-pressure control or load limiting'means hereof employs a known arrangement and principle of operation including the provision of special speed responsive means acting in a manner inverse to the usual speed weighing means of speed governors in that said special speed responsive means functions when the speed of the engine drops below a predeter minable point to limit the rate at which the hydraulically acting regulating means (e. g. power piston G) can cause fuel to be fed to the engine. Thus, for example, if the engine begins to labor heavily under the applied load, the fuel input will be cut down rather than increased as would ordinarily happen on a'governed engine when added load reduces speed. One advantage of the present arrangement, however, is that said function of the inversely operating special speedresponsive means (outlined above) cannot normally interfere in any way with the normal function of the main speed weighing means or cause the latter to lag or fail to respond quickly to slight changes in speed within the usual range of.

deviation from normal consequent upon expected load changes. Also, as herein adapted and arranged the special speed responsive mechanism has only to move a small value thereby to cause the necessary movement of the pilot valve to initiate operation of the fuel regulatage of fluid from the duct '0 into the sump ing servo-motor in theproper direction; whereby the special speed responsive mechanism. being never subjected to substantial load, can be made very sensitive and of small size. The main speed regulating governor mechanism and the B. M. E. P. control governor mechanism "float" independentlyof each other during load change and ordinarily the operation of neither has any influence on the other. schematically shown is as follows:

The inversely operating speed weighing means, as shown, is a rotatably mounted flyball head 4 turned through intermeshing-gears 2 and} on respective ball-heads l and l depending flybells 8, ends spring 8 within the body of the ball-head I and reacting upwardly against a plunger I in con'iasct with overhanging ball arm fingers of the flyballs I. Bearings for the ball head I are shown at 8 supported by the governor casing. The relation of flyball weight, length, etc. to the strength of the spring I is such that the flybalis I normally hold the plunger 1 in the depressed position shown, as against a shoulder I on the ball-head body 4. when the speed of the engine drops to a point at which (e. g.) the engine should not be subjected to increased fuel, as explained above, the spring 6 then raises the flunger I against the decreased centrifugal force of the flyballs 6. Bush would occur were the engine to become overloaded, as will be obvious. Upward movement of the plunger I of the ballhead 4, from the position in which shown, is in- 'eil'ectiwwhentMpomrpistmGisinacerttin spring Q being placed temporarily in tension by suction action of the compensation fluid sysposition intermediate ,0! the pper and lowerlimits of its stroke, for example somewhat below the mid position, illustrated. In such'lower posi- The arrangement as tions of the power piston the rateof feeding of fuel is under a safe maximum at any possible low speed, even with the engine subjected to abnormally heavy load and tending to stall. But when the power piston is in the upper range of'movement (as above the position in which shown) at a time when excessive engine load reduces the speed of the engine until the spring actuated plunger 1 is raised by the spring 6 then said upward movement of the plunger 1 causes the engine to be shut down (or the fuel to be decreased until the excessive load is removed) as follows:

A lever I is pivoted at one end, as at H, to a' vertically slidable bar l2, the lever having its free end resting on the plunger I. When the bar I2 is depressed the lower end of the bar operates a valve plunger 13, pressed upwardly toward the the power piston. A return spring I! for the bar v rod l2 as by a spring l4, and arranged and oper- I5 moves said bar downwardly, causing it to fol- I low the power piston. The rack teeth on the bar l5 mesh with a pinion or pinion segment l8 on a horizontal shaft [9 suitably supported in fixed position. A fulcrum member 20 on the-shaft l9 engages the lever II), as through a roller 2| on said lever, to enable the upward movement of the speci'al-flyball-actuated plunger 1 to depress the bar l2 increasing distances as the power piston moves through its upper ranges. Thus thespecial ilyball operated plunger 1 can depress the valve-operating rod l2. only when the speed-reg- So'longas the valve plunger l3 remains depressed, fluid from the high pressure side of the regulating hydraulic system can be prevented from leaking out of the compensation fluid duct 0 through the leak-off valve R, possibly causing failure of the B. M. E. P. control mechanism to effect a positive shutdown movementin a rela-- tively open adjustment of the leak-off valve, by so arranging the plug 29 that it blocks the duct 0 (as at the region occupied by the spring. '30,) whenever the passage ll is caused, by leftward movement of the plug 29, to communicate with the passages 26, 21 and 28. Thus the slowing'down operation performed by the B. M. E. P. control governor mechanism is positively assured under all circumstances.

When the valve plunger l3 moves to raised position, return movement of the plug 29 to the right, as against a shoulder portion of its guide (returned position shown) is enabled by providing a bleeder passage 32 intercepting the upper end of the guide bore 21 for the valve plunger 13 adjacent an upper land portion of said valve plunger, one end of the passage 32 communicating with the sump in a suitable manner. The 'bleeder passage 32 is closed by the upper land portion of the valve plunger it when the latter is depressed sufflciently to move the lower land '25 into unblocking relation to the high pressure admission passage 26. r

The downward pressure of the rod l2 on the. valve I3 ceases as soon as the power piston depassage '32 for communication with the bore 21 ulating servo-motor piston G tends to operate to supply fuel to the engine at ratesabove the predeterminable maximum mentioned above, for

otherwise the fulcrum member 20 'is rotated pressure space of the pump and accumulator.

When the plunger I3 is depressed, constantpressure fluid flows through the passage 26, past a and, thereupon, fluid pressure in the duct 0 is reduced to sump pressureby flow of operating fluid from the ductO- through passage 3|, the guide bore for the plug 29 and the passage 28. Any pressure above sump pressure remainingin the duct 0 after the plug 29 closes the uppere'nd of the passage 3! escapes by way of the needle the engine. e

The member 35 shown in alignment with the upper end of the shut-down bar I2 is a hand operable device having a stem 36 poised over the bar II or lever III to cause shutting down of the neck portion of the valve plunger l3, through the to subject fluid in said duct 0 to high pressure.

Except when the hydraulic compensation sys tem is in operation as earlier explained, the prese sure in' the compensation fluid duct 0 is negligible; and it will be seen therefore that diversion of high pressure fluidto the duct 0 will act on the receiving compensation piston P to raise it, placing the spring Q in compression and thereby raising the pilot valve plunger H against the opposing action of the speeder spring M. This causes the power piston to descend, as already explained, because the upward movement of the pilot valve plunger dumps high pressure fluid from below the power piston G.

engine .at any desired time, as in an emergency,

. independently of the B. M. E. P. control mecha- 5s nism and. main speed responsive means. I

I claim:

.1. A speed governor combination-comprising a main speed responsive governor mechanism including control means and regulating means adapted and arranged to cause increased input to aprime mover upon increase in load and vice versa, an inversely operating speed responsive governor mechanism including a normally closed operatively associated with the main governor control means and caused to act thereon in a. manner to oppose the usual action thereof upon decrease in speed of the governed prime mover, whereby in event excessive. load on the prime mover depresses the speed thereof to such an exa tent that increased input .is then undesirable,

said inversely operating mechanism can, by control of said valve, prevent the first governor mechanism from causing further increase or in- 7 put to the prime mover in said event.

2. In a. speed :overnor ior prime movers, a main hydraulic relay governor mechanism-ineluding speed responsive means, pilot valve means operated thereby and a regulating servomotor controlled by the pilot valve means-, ar-

ranged normally to control the speed of the 10 prime mover, a secondary speed responsive mechanism, a source oi hydraulic pressure fluid.

- a hydraulic system operatively Pirate from the hydraulic relay and including hydraulically displaceable means connected to an element of the pilot valve for movement of said element, a valve associated with said system and normally disconnecting said source and the system, and means adjusted by the joint action of the servomotor and the secondary speed responsive mechanism i'or operating the valve to connect said source and hydraulic system for operating the pilot valve means independently "of the ilrst mentioned speed responsive means. v I

' ALBERT mum.

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