US2603472A - Governor for internal-combustion engines - Google Patents

Description

y 15, 1952 H. G. ADLER 2,603,472

GOVERNOR FOR INTERNAL-COMBUSTION ENGINES Original Filed June 28, 1943 2 SHEETS-SHEET 1 g ll/wwww A oRNEYs u y 1952 H. G. ADLER 2,603,472

GOVERNOR FOR INTERNAL-COMBUSTION ENGINES Original Filed June 28, 1943 Y 2 SHEETS-SHEET 2 INVENTOR. HERMAN G. ADLER ATTORNEYS Patented July 15, 1952 GOVERNOR FOR INTERNAL-COMBUSTION ENGINES Herman G. Adler, Detroit, Mich., assignor' to Novi Equipment Company, Novi, Mich., a corporation of Michigan Continuation (pf-application Serial No. 492,605,

June 28, 1943. This application Novemberfi, Y 1947, Serial No. 784,150

17 Claims. (01. 26414) The invention relates to governors for internal combustion engines of that type designed to restrict the speed to a predetermined maximum while permitting the development of power necessary for varying loads.

It is a primary object of tain a construction which is applicable to high powered engines in which the operation of the governing valve or throttle requires considerable l 10 It is a further object to obtain a construction power.

which will hold the governing valve in each position of adjustment against fluctuations or hunting which is a fault of many governing devices.

Still further it is an object to obtain a simple construction which makes use of available equipment of internal combustion eng'inesin the development of power for: operating the governing mechanism. I

With these and other objects in view,the invention consists first in a construction in which the throttle or governing valve is actuated by a hydraulic motor deriving its power from the pressure oil system of the engine; second, in a construction in which there is normally 'a continuous restricted flow of the hydraulic fluid through the motor whenever the engine is in operation'to be available for instantaneous use; third, in a construction in which the hydraulic motor not only actuates the throttle valve but also forms-in effeet a dashpot for checking oscillations thereof; fourth, in a construction in which a pilot valve admits pressurefiuid to both sides of a control piston as the valve moves betweenlimiting positions; fifth, in a construction in which a pilot valve uncovers a restricted port to control fluid flow to a piston to operate the throttle; and sixth, in various features of construction as hereinafter set'forth.

In the drawings:

Figure l is a diagram illustrating my improved engine governor; 1

Figure 2 is a vertical longitudinal section through the centrifugally actuated valve mechanism for controlling the hydraulic motor;

Figure 3 is an end elevation thereof;

Figure 4 is a bottom plan view illustrating the inlet and outlet connections to the valve;

Figure 5 is a longitudinal section through the hydraulic motor and its connections by which the controlling valve or throttle is actuated;

Figure 6 is an end elevation of Figure 5;

Figure? shows the bifurcated connection between the piston rod and lever;

Figure 8 is a diagrammatic View of the valve the invention to obshown in Figure 2 in the position which it occupies as a result of over-speed of the engine;

Figure 9 is a section on the line 9-9 of Figure 8;

Figure 10 is a diagrammatic view similar to Figure 8 showing the valve in the position which it occupies as a result of under-Speeder the en-' gine.

With large size internal combustion engines the frictional resistance to the operation of a governing valve or throttle is relatively large.

Consequently the operation of the same directly v by a centrifugal governor would require a-mechae nism of prohibitive size. One method which has been used to reduce this frictional resistance is to provide an auxiliary throttle box mounted be tween the carburetor and manifold andequipped I with antifriction bearings. However, this, results in an undesirable disturbance of the carefully worked out fuel mixture ratios and is also unsatisfactory in its governor performance, pare ticularly with large engines. The latter difiiculty is due to thefact that large engines em-,

ploy largevalves upon which act relatively large unbalanced torques even when these valves are geometrically in balance. These torques form a large percentage of the governing force and varyin such a manner that it is impossible to attain close regulation without introducing hunting.

Furthermore, when the carburetor valve is partly closed at governed speed, the torque acting upon the. governor valve is thereby changed with the result that hunting takes place in an otherwise stable governor.

To overcome these difficulties, I have devised a construction of governor in which the centrifugally actuated governor mechanism operates only a controlling valve of a hydraulic motor which latter furnishes the requisite power for actuating the throttle. Also, as above stated, the construction is one in which the fluid for operating the hydraulic motor is derived from the pressure oil system of the engine, and a further feature is that the oilcontrolled .by the valve normally has a constant restricted flow throughthe motor whenever the engine is in operation.

Described in general terms, the governor comprises a piston operatively connected to the throttle valve of an internal combustion engine, a pilot valve for controlling admission and exhaust of fluid under pressure to the cylinder, and speed responsive means connected to the engine for directly controlling the position of the valve. In order to prevent speed fluctuations and surges known as hunting, the construction employs 3 three constructional features. A constantly open by-pass interconnects opposite ends of the cylinder, and is herein illustrated as provided by a restricted port through the piston. The pilot valve is proportioned such that ,in moving to change; the direction of flow of fluid through the cylinder, it simultaneously connects'both ends of the cylinder to supply for a short distance of Finally, in moving to connectthe cy'l'- travel.

inder to pressure fluid to move the throttle, the, pilot Valve uncovers a restricted port, which functions as an inlet or exhaust port depending upon the direction of valve movement, .while second port in the system, which is simultaneously uncovered is not so restricted. These features cooperate to reducethe-sensitivityof the governor, and in practice result in a small speed throttle.

7 Referring 'now to the drawings, and more particularly Figurez', the speed responsive device-comprises agovernor shaft l connected to a rotating part of the engine, such for example 7 The governor shaft H3- is mounted at one endin a radial and end thrust bearing l2 mounted in a housing l3 carried by engine casing i4 and covering an opening proas the cam shaft vided therein.

Mountedon the shaft lfiis a circular plate, .|5,. a ball thrust bearing It being provided'betweenpliate. |5 and a shoulder I? on the shaft. A cup-shaped member i8 is, rotatably mounted I on shaft I5, being carried by a longitudinally movable hub H3, and has a conical portion 25. r

A plurality. of balls 2| are provided between plate l5 and cup. I8, and are rotativ'ely driven by a radially slotted driver 22 rigidly secured to the shaft. f

Collar 23 is sleeved upon hub IQ, thrust bearings 24 being provided between cup |8' and col lar 23. The collar has a shoulder 25 which forms a bearing for a lever 26 which is fulcrumed in the casing |3and is apertured to embrace the shaft I0 and the collar 23. The, opposite sides of lever 26 have rounded bearing portions 21 engaging the surfaces 28 of shoulder 25, and its movable end has a rounded bearing portion 30 for engaging the end of a slide'valve 3|.

Valve 3|, as best seen in Figures v8 and 10, is of hollow cylindrical form, and slidably engages a cylin'derliner 32 positioned in a,cy'lindrica1ly formed portion 33 of easing I3. The liner has a supply port 35, and a pair of inlet or'exhaust ports 36 and 31 connected 40, respectively. I

The valve 3| has cylindrical lands d3 and'M spaced apart by a reduced portion 45, which is always'in communication with supply port 35. Land 44 is of a width just suflicient to cover port 31. Land 43, however, is slightly narrower than the length of port 36. Lands 43 and 44 are spaced apart by a distance slightly greater than the distance between ports 36 and 37. Therefore as valve 3| moves over ports36 and 31 so Furthermore, at either side of this,

to conduits 38, 39 and,

,trolledbythe opening of port 36. relatively large port 31 is functioning as an exhaust port, and the relative sizes of the openings portsjfi'and 3i insure-against back pressure 4 as to reverse the direction of flow through conduits 39 and 40, there is a position at which inlet port 35 is connected to both ports 36 and 31, and ports 36 and 37 are cut off from exhaust.

In order that the operation of this aspect of the invention may be fully understood, a typical valve 3| and sleeve 32 were dimensioned as follows: Circular portion of port 36 was in diameter, the slotted portion was .093" wide,

and its over-all length was .389". 3'75" jacent edges of ports 36 and 31 was .550. '43 and. of valve 3| were each .375" Wide, and

wergs p'ace-d; apart a distance of .582".

Port 31 was The distance between ad- Lands in diameter.

Port 3? is' preferably circular, whereas port is specially shaped to restrict fluid flow. As j -seen inFigu're' '9, port 36 is shaped to provide 7 an'initiall-y restricted opening as valve land 53. moves to uncover it to fluid supply. Movement of piston 51 in throttle-closing direction is con- At this time in the cylinder 56 preventing'quick response.

Therefore overrunninggis prevented," and the danger of excessive. engine speeds is eliminated.

Uponfdecrease of speed, port 36 is opened from its large end'to function as an exhaust port, and porttl is open to fluid supply as an inlet port. Therefore back pressure builds up in cylinder chamber 10, and piston movement is controlled chieflyjby" control of exhaust flow through port 36.: This movement of the piston is in throttleopening direction, and lagcannot result in dangerous over-speeds ofth'e engine, as might result fromzoppositejmovement delay or lag in opposite movement of the piston.

The source of hydraulic fluid under pressure may conveniently be the lubricating pump of the engine; and hence exhaust through valve 3| may "be freely into the casing I3, whence it returns to the lubricating pumpf The head 48 of'the valve has a plurality of radial exhaust passages t9 which communicate with the hollow interior of the valve. 'Ihus'whe'n exhaust is through port 3$,fiu'id flows through-the hollow valve 3|, and through passages 49 to-the interior ofcasing. 13.

When exhaust is through port 31, flui'd is' exhausteddirectly into the interiorgof casing I3.

'Valve head 48 is engaged by the movable end or lever 2fi,-'as-abovede scribed, and is retained in engagementtherewith by an adjustable governor spring 59. 3 Spring fiil bears at one end againsti 'theinnersurface of the valve "head 48,

and at-its other end'againstia spring seat 5| mounted on an adjusting screw 52 threaded into a removable closure" =53 carried v by casing l3. Lock nut 54 prevents accidental displacement of screw 52, and a protecting cap 55 is provided which threads over the outer end of screw 52.

With the construction as thus far described, it will be evident that with increase in angular velocity of the shaft llLballs 2| will be urged outwardly-by" centrifugal action and as these balls bear against the obliquely inclined face 20 of the cup member] 8, they'will cam this member axially upon the's haft'lfl'. This movement is transmitted through'collar 25 to lever 26, and thence to valve 3| "which is'moved against the compression of spring 59. V j V The-hydraulic motor unit shown generally at 55a in Figure 5 is mounted in any convenient location upon the engine and is connected to the throttle of the engine. The unit comprises a cylinder 56 containing a piston 51- to which is connected a piston rod-58 passing outward from the cylinder through a head 59 and packing gland 6ll.- A guide rod 53 on the piston slidably engages a bore guideway in the head 59 and serves to preventrotation of the piston in the cylinder. A buffer or bumper spring 6| is provided around the rod 58, which engages shoulder 62 on the'rod under no-load conditions and prevents hunting which might otherwise occur.

At the outer end of rod 58 is a'bifurcated member 65 which provides a fulcrum bearing for a centrally pivoted lever 66. As diagrammatically shown in Figure 1, one end of lever 66 is connected by a rod 61 with the throttle valve 68, while the other end is connected by a rod 69 to the accelerator pedal 15. Thus, in the position of parts shown in Figures 1 and 5, lever 66 is free to pivot under actuationof the accelerator pedal to move the throttlewithout interference from rod 58. On the other hand, movement of the 'rod 58 will operate the throttle valve, the accelerator pedal connection acting as a fulcrum for lever 66. 1 1

As previously stated, the oil or hydraulic fluid for' operating the motor unit 55a is preferably supplied from the lubric'ation' pressure system of the engine. From this system inlet conduit 33 leads to valve inlet port 35'. Conduits 39 and '49 lead respectively from the ports 36 and 31 to the cylinder 56, and communicate respectively with chambers 16 and 1|. A restricted by-pass between chambers 10 and 1| is provided by a passage 12 extending through piston 51. Passage 12 isv quite small as compared to ports '36 or 31.

. Operation.

From the foregoing description it will be understood that when the engine is running at the governed speed valve 3| may be in an intermediate position, at which time it connects both ports 36-and 31 to pressure fluid. This insures that cylinder 56 and conduits 39 and 46 are completely filled with fluid. r

If the engine speed increases centrifugal action causes outward movement of the'balls 2| which results in movement of the cup l8 to the left as'seen in Figure 2 and this in turn rocks lever 26 clockwise as seen in this figure, moving valve 3| to'the left. Figure 8 illustrates a positionoi valve 3| to the left as above described, this position resulting from an engine speed greater than that'for which the governor is set. Fluid admitted through port 35 passes through port 35 into conduit 36 and thence into cylinder chamber 10, thus tending to move piston 51 to the left, which results in movement of the throttle valve toward closing position. a It will be recalled that the port 36 is relatively smaller than the port- 31 V and in addition is shaped so as to initial restricted opening upon movement of. the valve 3|; Thismovement of :the, valve3| opens the'port -31 to permit exhaust of fluid-from the cylinderwand due to the relative'dimension of the provide for ports 36v and 31, the exhaust flowof fluid under s these. conditions is substantially unrestricted 1. when the open area of port 31 exceeds-the open area of port 36. This permitsmovement of the -pis ton; 51- toward throttle-closing position at a rate determined substantially by the uncovered areaofport 36which at this time is operating as an inlet port. The relatively large opening of the v port; 31, which at thi's time is operating as the exhaust port, prevents the building up of back pressure in cylinder chamber 1|. This is an impo'r't'ant feature since it effectively prevents sub-' might result if response were delayed as a result of back pressure building up in cylinder chamber 1|. Accordingly, if there is an instantaneous substantial reduction in load on the engine the foregoing described arrangement insures prompt closing movement of'the throttle valve immediately upon the speed of the engine exceeding the speed set on the governing 'apparatus,

If the engine speed falls below the governed speed balls 2| move inwardly, cup l8 moves to the right as seen in Figure 2, lever 26 moves counterclockwise and the valve 3| moves to the right as seen in this figure under the force applied thereto by the compression spring 5!). This .position of the valve 3|, corresponding to an underspeed engine condition, is illustrated in Figure 10. In this figure it will be observed that port 31 is now in communication with pressure fluid and fluid therefore flows through conduit 49 into cylinder chamber 1|. 'At the same time the opposite side of the cylinder is connected through the-cylinder 56,, has an open area substantially larger than the open area of the port 36 which is operating as the outlet port tovthev cylinder. Accordingly, flow of fluid is primarily controlled by the opening in the port 36 and the movement of the piston 51 is thereby controlled except as modified of course by the action of 1 the. piston by-pass port 12. This will result in the building up ofback pressure in cylinder chamber 19 so that the resulting movement of the throttle controlling piston 51 is damped' This prevents overcontrolling. There is no particular harm that can result from the engine speed dropping below the set governorspeed as may result in this instancefwhere'as excessive engine speed may easily result in damage to the engine.

A veryimportant feature of theconstruction is that piston by-pass 12' imposes a constant restriction to flow of oil therethrough,while ports 36 and31 are varied in area and restriction of flow of fluid therethrough by different positioning of valve 3|. The restriction afforded by by-pass 12 is generally greater than that afforded by the other ports but willpermit sufficient flow tocheck oscillation 1 of the piston.

' Variations'in the reactive force of the throttle valve on the'piston will be balanced by the variations in fluid pressure on opposite sides of the piston resulting in part from pressure drop through by-pass 12. Furthermore, the piston cannot be displaced by such reactive forces without producing a corresponding displacement of fluid through the restricted ports, so that the motor acts as a dashpot.

The arrangement whereby valve 3| operates to connect both ports 36 and 31 to pressure'in one position, the relationship between the size and shape of the ports 36 and 31, and the provision of a piston by-pass port 12' all cooperate to result in stable operation. There is a limited range'at and below the governed speed throughout which the governor is substantially insensitive. Overcontrollingwith' resultant violent variations in speed is thus e'ifectively prevented by an extreme- 1 1y simple construction involving as'it does only a centrifugal device operating. directly on a pilot valve which controls admission and exhaust of fluid pressure to a piston and cylinder device 'mechanically connected to the'throttle.

.Reference was previously made-to the bumper spring'fil which is adapted to-be engaged by the shoulder 'fizwhenthe piston :51-is moved'far to the left as seen in Figure 5. "Theft-motion of this spring'is topprovide forin'creasedstabilityof the structure underno -load conditions. Under these conditions small variations in throttle opening may result in widespeediiuctuations of the-engine. By providing thespring-sl'the tendency toward instability under no-load conditions is avoided. v V

The present application is "a continuation :of my :prior co+pending application, Serial -.No. 492,605, now-abandoned, whichlwasfiled June 28, I943.

The drawings and the foregoing specification constitute ai'description'of the improved:governorfor internal combustion engines insuch tiull, clear, concise-and exact terms as toenable-any person skilledin .theart to practice'the invention, the scope, of which is indicated the appended claims.

What I claim as my invention is; 1. A speed overnor for intermal combustion engines comprising :a -source of hydrai-ilic fluid under pressure, a cylinder andipis-ton: hydraulic motor-connected to the engine'throttle for actuation of the same, said motor having a restricted by-pass fromrone side to the other of said piston, a valve controlling said motor having'portsconnecting with said cylinder on opposite i-sidesof the piston therein, also pressure fiuid inlet jand exhaust ports, said valve in'n-ormal positionqpermitting' continuous flow of .fluidfromsai-d' inlet through one of said cylinder connec-tingiports, said by-pass and-the other of said 'cylinderlcon-r necting ports to said' exhaust, the restriction of said bye-pass producing :a differential, pressure on opposite sides .of said piston .to hold the latter in open throttle position, and centrifugal-meansfor shifting said valve toward a'position for.reversing said inlet and 'exhaust-oonnections to said cylinder ports, .said valve being adapted in passing'from itsnorm-al position to temporarily'connect :said inlet port with both of said cylinder connecting portswhereby difierentia-l pressure on said 'piston is gradually "changed to shift :said throttle toward closedcposition with avoidance of hunting. c E

2.'A" speed governor for internal:-combustion engines having a single throttle and. an :a'ccelerator pedal for operating the same, said-governor comprising alsource ofihydraulic fluid undenpressure, a cylinder and piston hydraulic -moto-r also connected torsaid throttle, alever forming -acommon link' in the'ped'aland motor-connections to said throttle permitting independent operation of either one, said motor having a restricted by-pass from one side to the other of :said piston,-;a valve controlling said motor-having ports-:connecting with said cylinder on Opposite sides. of the.- piston therein, also pressure fluid inlet; 'and exhaust ports, said valve 'in' normal position; permitting continuous 1 flow of fluidfrom: said inlet through oneof said cylinder connecting'ports, saidlbypassand the other of said cylindericonnecting ports to said exhaust, the restriction of *said bypass producing a difierential pressureontopposite sides ofsaid piston to holdthez-iat-ter in openthrottle position,--andcentrifugal means for, shifting said valve toward a-positi-on for-reversing said inlet and exhaust-connectionsto said cylinder ports, said valve being adaptedimpassing from its normal position to temporarily :coni nect said inlet; port with both of said cylinder ports whereby :di-fierential pressure on said piston is'gra'dually changed to shift said-throttletoward closed positionwith avoidance of hunting.

3; A Speedgovernopfor internal-combustion engine's comprising a source of hydraulic'fiuid under pressure,:- a cylinder and piston hydraulic motor-connected to the engine-throttle ior actuation of the same, :said motor havi-ng arestricted by-pass from one side to the other ofsaid piston, a valve controlling-said motor havingports connecting with said cylinder on opposite sides of the piston therein, one of said 'ports having a restricted extension toward-the other of said .ports, zalso pressure fluidinlet and exhaust ports, said valve in normal position permitting continuous flow of fluid-from said inletthrough one -of :said cylinder connecting ports, said bypass and,

the other of said cylinder connecting sports to said exhaust, the restriction of said-by -pass producing a difierential pressure .on opposite sides of said piston to hold the latter in open-throttle position, and centrifugal means for shifting said valve-toward a position for reversing saidin-let and exhaust connections to said cylinder-ports, said valve being adapted in passing from itsnorma-l position to connect said inlet portsyith both of said cylinder connecting 1 ports and --thr0llgh the restricted extension of the one whereby differential pressure on said piston is -gradually changed to shift said throttle toward closed-positi-on with avoidance "of hunting.

-4.-A speed govern-or for internal combustion engines-comprising a source of hydraulic fluid under pressure, acylinder and-pistonhydraulic motor connected tothe"enginethrottle-for:actuation of the same, said motor having a restricted by-pass from one side to the other of said piston,

-a valve controlling said 'motor having "ports connecting-with said: cylinder on oppositesides-of --the piston therein, one'ofsaidports having-a' restricted extension toward the other of said ports, also pressure fluid inlet and exhaust-ports,

said valve in normal position, permitting-continexhaust, the restrictio-nof said by-paSs producing andiiferential .pressure on opposite sides of said piston to hold the latter in open-throttlepos-ition,: centrifuga1 means for shifting isaid valve toward a position forreversing said inlet and exhaust connections to said cylinder ports, -said valve being adapted in passing from its normal position'to connect said inlet; port with both of said cylinder connecting ports and through the restricted extension of the one whereby difierential' pressure on said piston is gradually-changed torshi'fti'said throttle toward closed position with avoidance of .hunting, :and a resilient buifer for resisting inertial over-movement of said :piston. :5. *Aspeed governor for internal-combustion engines comprisingasource of hydraulic fluid :under 'pressure, a piston and cylinder hydraulic motor mechanically connected to the engine 6 throttlefo'r actuation of the same, :a restricted 'by-pass connecting opposite ends of'said'cylinder, a valve controlling said motor comprising a sleeve having end ports connecting with said cylinder on opposite sides of said piston and an inlet port intermediate said'end ports,-and ava'lve element in said sleeve movable in accordance-with engine speed and having end portions closely fitting x'w'ithin said sleeve "and adapted to control the open area of. saidend'ports, and a -reducedportion intermediate "said end 'portionsalways in from.

communication, with said inlet port, the, inner r edges of theend-portions of said valve element said end-ports, whereby upon movement of said valve-elementalong said sleeve, said inlet portis simultaneously connected to both of said end .ports,.said end ports aifording connections to the corresponding ends of'said cylinder to exhaust when the adjacent end portions of said valve element pass inwardly of said-sleeve there- 6. A speed governorgfor internal combustion engines comprising a source. of hydraulic fluid under pressure, a piston and cylinder hydraulic motor mechanically connected: to the engine throttle for actuation ofgthe same, va restricted by-pass connecting opposite ends of said cylinder, a valve controlling said motor comprising a sleeve havin end ports connecting with said cylinder on opposite sides of said piston and an inlet port intermediate said end ports,,and a valve element in said sleeve movable in accordance with engine speeds having end portions closely fitting within said sleeve and adapted to control the open area of said end ports, and areduced portion intermediate said end portions always in communication with said inlet port, the inner edges of the end portions of said valve elementbeing spaced apart axially of said element further than the spacing between the inner edges of said'end ports, wherebyupon ,movement of said valve element along said sleeve, said inlet port is simultaneously connected to both of said end ports, said endports affording connections to the corresponding .ends of said cylinder to exhaust when the adjacent end portions of said valve element pass inwardly of said sleeve therefrom, the end port communicating with said cylinder at the side of said piston eifective to move said motor in throttle-closing direction having a restrictive opening first uncovered by movement of said valve element in response toan increase in 'eng'ine'speed, and a larger opening uncovered by further movement of said element in the same direction.

7. A speed governor for internal combustion engines comprising a source of hydraulic. fluid under pressure, a piston and cylinder hydraulic motor mechanically connected to' the engine throttle for actuation of the same, a valve for controlling admission and exhaust of hydraulic fluid to and from opposite ends of said cylinder including p'orts connected with opposite ends of said cylinder, and a valve element movable in accordance with engine speed and having portions to connect said ports alternately to saidsource of fluid under pressure and to exhaust, and-a restricted by-pass connecting opposite ends ofsaid cylinder and effective to damp the movement of said piston to reduce the tendency of the governor to hunt.

8. In a speed governor for internal combustion engines comprising a source of hydraulic fluid under pressure and a piston and cylinder hydraulic motor mechanically connected to the engine throttle for actuation of the same: a valve for controlling admission and exhaust of hydraulic fluid to and from opposite ends of said clinder including ports connected with opposite ends of said cylinder, and a valve element movablein accordance with engine speed and having portions to connect said ports alternately to said source of fluid under pressure and to exhaust and constructed to have appreciable intermediate movement throughout which it connects. both of said ports to said source of fluid under pressure one of said ports being relatively restricted as compared to the other,"whereby movement-of said piston in one direction is efffected without substantial back'pressure' and is ,lcontrolled by the inlet flow of fluid, and movement of saidpistoninthe other direction is controlled'primarily by controlof exhaust flowof fluid. r I l0 9. In a'speed control system for an. internal combustion engine comprising an engine throttle, a' reversible fluid 'motor, for positioning the throttle and having motor ports each of which 1 is adaptedlto function as an inlet or exhaust port dependent upon the direction of movement of the motor, and a speed responsive device including a movable member positionable in accordance with engine speed: 'avalve structure for controlling flow of fluid through the motor comprising a pair of valve ports adapted to be-con'nected to the motor ports, a slidable valve mechanically positioned by said movable member dimensioned in intermediate, position to close both of said valve ports to exhaust and to provide restricted openings at both of said valve ports to fluidunder pressure, the valve port which functions as'an inlet port to the, motor during overspeed conditions being shaped in relation to the valve associated therewith to provide a valve opening which opens more slowly upon movement of the valve than does the other valve part upon movement of the valve in either direction from its governed speedposition; v v,

10. In a'speed control system for an internal combustion engine comprising anengine throt- ItleQareversible fluid motor-for positioning the ,throttle and having motor ports eachof which is adapted. to function as an inlet or exhaust port dependent upon the direction of movement of the motor, and a speed responsive device including a movable member positionable in accordance with engine speed: a valve. structure for ccntrollingl flow of fluid throughjthe' motor comprising a pair of valve ports'adapted tobe connected'to the motor ports, a slidable valve mechanically positioned by said movable'member dimensioned in intermediate position to close both of said valve ports to exhaust and toprovide restricted vopenings at both of said valve ports to fluid under pressure, the .valve, l QIt which functions as an inlet port to the motor duringuoverspeed conditions being shaped infrelation to thevalve associated therewith to provide a valve opening which opens more slowly upon movement of the valve than does the other L valve port upon movement of the valve in either direction from its governed speed position, but

' whichopens'more rapidly in response to valve rnovrament resulting from decreases in engine sponse to increases in speed above governed r speed. Y

speed below governed speed than it doesin re- 11. In a speed control system for an internal combustion engine comprising an engine throttle, a reversible fluid motor for positioning the throttle and having motor ports each of which is adapted to function as an inlet or exhaust port dependent upon the direction of movement of the motor, and a speed responsive device including a movable member positionable in accordance with engine speed: a valve structure for controlling flow of fluid through the motor comprising a valve cylinder provided with axially spaced valve ports in the side Wall thereof adapted to be connected to the motor, a supply mam portin thewall. thereof intermediate SaidQVQL'IVB ports, a spool valve having axially spaced lands anda central reduced portion always in communication withsaid supply portfthe .one of said valve portsoperable as a supply'port'uponincrease in engine .speedfaboveggoverned speed l being. shaped relative to' the valve .land cooperable therewith as to open more slowly :upon valve movement ineither direction than does "the other valve port. V l2 1113158136611 control system for; an internal combustion engine comprising an engine. throt- 'tle, a reversible ".fiuid inotor. .for positioning the throttle'and' having-motor ports each of which l adapted :to function as .an' inlet. or exhaust ;port dependent upon. the direction of :movement of the motor, and .a speed responsive .device .infc luding 'a movablegmember. positionable in accordance with engine speed: a valvestructure f0 r .controlling flow of .fluid through the motor .comprising a valve cylinder provided with axially .spaced valve portsv in :the side wall thereof adapted to be connected .to the motor, a-supply port .in the wall thereof .intermediate 'said'valve 1 ports, a spool valvemovablefby said member and having axially spaced lands and acentralre- "duced'portion always. in communication with said supply port, the one of said valve ports 'opera'bleLas a supply port upon increase inengine fspeed abovegoverned speed having an opening which. is relatively restricted at the end adjacent the other valve port and relatively enlargedatthe -other end, said other valve port being of larger size. than said one valve port, the land cooperablewith said other valve port being cylindrical and having an axial extent equal to said other value port,.the land cooperable'with said one valve port being. cylindrical and having an axial extent slightly less than the axial extent of said 'one valve port, the axial spacing between the lands being. slightly'greater than the axial spac "ing between said. valve ports, and the outer ends of said lands 'being spaced apart a distance slightly greater than the outer edgesofsaid valve ports. 1 1'3. A speed governor for an internal combustion engine having a throttle comprising .a source of hydraulic fluid under-pressure, a reversible hydraulic motor'mechanically connected to the engine throttle, a valve structure for controlling "the flow ofifiuid through said motor, a by-pass providing a restricted ,fiow of fluid from'oneside to the other of said motor, said valve structure comprising a valve cylinder provided with axially spaced valve ports in the side wall thereof adapted to be connected to the motor, a supply port in the wall thereof intermediate said valve portsy'a spool valve movable in accordance with engine speed and having axiallyspaced lands .and a central reduced portion always incom- 'munication with said supply port, the one of said. valve ports operableas a supply port upon said cylinder.

jiincrease' in enginespeed ahove governed speed having an opening which is relatively restricted at the end adjacentthe other valve-port -and relatively-enlarged at the otherend, said other valve port'being of-larger size-than said one valve port, the land cooperable with saido'ther valve port --bei-ng cylindrical and having an axial extent equal to said other valve port, the 'land cooperable with saidonevalve port jbei-ng cylindrical and having an axial extentslightly less than the axial extent of said one valve port, the axial spacing between the lands being slightly greater than the ax-ial spacing'b'etween said valve ports, and the outer ends of said lands-being spaced apart a distance slightly g-reaterthan the outer edges of saidvalvepor-ts; V e f 14. Mechanism asdefined in claim 13 in which i said motor comprises a pis'ton andcylinder, and

said byepass comprises a restricted port through '15. A speed governor for anfi-nterna'l combustion engine having a throttle, a piston and cylinder-hydraulic motor-connected to said throttle, a restricted iiuid-by-pa-ss irom one side of said piston to the other; a source of hydraulic fluid underpressure} 'a valve structure connected to said fluid-source and having 'apair; of ports connected respectively to" opposite' en ds of said cylinder, a "valve element" associated withsaid ports and relatively movable thereto 'in accordance with engine speed, -sa-id va'-1ve "element including closure portions which" under stable 'condi-tions connect one port toilui-d'under pressure and the other port to exhaust, thus providing a constant flow through said by pass.

116.: Mechariism as id'efinedin cam. 5 a which under stable conditionaithe-port opening. of the 'port connecte'd to fluid under pressure. is inwj creased upon movement of said" element response to increase in engine speed. r 17;. .Mechanism as defined in claim 16 in which said" portions first sin' ultaneously close both of .said ports to exhaust. and". connect :both of said ports to 'fluidpressureland' then reverse the fluid pressure-exhaust"relationship of said ports upon movement of saidelem'ent in response to ajsubstantial decreasein enginespeed.

7 AD'LE'R.

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

- UNI'I'EDaS'I-ATES PATENTS 2,373,684 Holloway 1 Apr. 17,

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