US2539738A

US2539738A - Engine governor

Info

Publication number: US2539738A
Application number: US55506A
Authority: US
Inventors: George B Grim; Kenneth J Fleck
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1948-10-20
Filing date: 1948-10-20
Publication date: 1951-01-30
Anticipated expiration: 1968-01-30

Description

G. B. GRIM ETAL.

ENGINE GOVERNOR Jam m @9511 6 Sheets-Sheet 1 Filed Oct. 20, 1948 A 7' T ORA E X 6- B- GR'IM HA Jan. 3@, E951 ENGINE GOVERNOR Filed Oct. 20, 19

6 Sheets-Sheet 2 G. B. GRIM ET AL Jam. 3@, 195-1 ENGINE GOVERNOR 6 Sheets-Sheet 3 Filed Oct. 20, 1948 G. B. GRIM El AL.

ENGINE GOVERNOR Jam. 36, W51

6 Sheets-Sheet 4 Filed Oct. 20, 1948 JNVENTORS.

G. B. GRIM ET AL ENGINE GOVERNOR Jan. 30, 1951 6 Sheets-Sheet 5 Filed Oct. 20, 1948 INVENTdRS. ory Fr/m M44 Q? yiy ATTOR EX Patented 1.... 30.1951

ENGINE GOVERNOR George B. Grim, Washington, and Kenneth J. Fleck, Peoria, IlL, assignors to Caterpillar Tra'ctor 00., Peoria, 111., a corporation of California Application October 20, 1948, Serial No. 55,506

2 Claims. (Cl. 264-3) This invention relates to governors in general and moreparticularly to a governor of the centrifugal type for varying the quantity of fuel supplied to an engine in response to changes in engine load.

It is conventional practice, in an engine employing one or more fuel pumps for metering the quantity of fuel supplied to each of the working cylinders, to associate a fiyweight governor with a fuel pump control member in such a manner that the action of the flyweights under centrifugal force urges the fuel control member in a direction to decrease the quantity of fuel metered to the engine. A main governor spring is normally associated with the fuel pump control member load on the governor spring. Due to the number.

of manually operated controls necessary to guide the tractor and control various tractor-mounted or tractor drawn implements, it is impractical in such a manner that its force opposes the action of the flyweights. The governed speed of the engine is controlled manually by a. lever associated with the spring in such a manner that the force of the spring opposing the flyweights is determined by the load applied to the spring by the manual control lever. 'A suitable stop is usually provided to limit the movement of the fuel pump control in a direction to increase the fuel supplied to the engine thus limiting its maximum output.

In this type of governor, the speed differential between "no load governed speed" and the speed of the engine at full load" increases as the governed speed of the engine is decreased. This is caused by the force exerted by the flyweights decreasing with the square of the engine speed while the force exerted by the governor spring decreases directly with its deflection. Thus at lower governed speeds, a greater change in speed is required to allow the governor spring to move the fuel control member to its fully opened position than would be required at a higher speed. As a result, under some operating conditions, the engine will stall before the fuel metering control member reaches its fully opened position,

This characteristic is undesirable in most applications and is particularly so for vehicles such as tractors or the like. In such a vehicle which may operate over rough terrain or in narrow confines, it is often desirable to reduce the governed speed cf the engine to ease into or assume a load gradually and still be able to exert maximum engine torque without further manipulation of the manual control. However, if the load applied to the governor spring to give a satisfactory no load speed is not sufiicient to effect movement of the fuel control member to its fully opened position, the vehicle will either stall or be required to operate at reduced torque unless the operator moves the manual control lever to increase the under many circumstances for theoperator to devote one hand to the manipulation of ,the governor control.

This condition is particularly aggravated when a yieldable fuel stop or the like is associated with the fuel control member to establish a so-called "rated output of the engine below its maximum. Such devices oppose the action of the governor spring and require an additional force to achieve full travel of the fuel metering control member.

It is, therefore, 'an object of this present invention to provide an engine governor that will permit full travel of the fuel pump control member throughout the governed speed range of the engine; Another object of this invention is to provide an engine governor that will maintain a constant speed differential between no load governed speed and full load at any governor setting. It is a further object of this invention to provide a yieldable stop associated with the fuel control member which permits additional movement of the fuel control member when the engine is loaded beyond its rated load, such stop being so arranged that it requires a lesser deflection to permit full travel of the fuel metering control memher as the governed speed of the engine is decreased.

Other objects and advantages will be made apparent in the following specification wherein reference is made to the accompanying drawings.

In the drawings:

Fig. 1 is a schematic longitudinal sectional view through a governor incorporating the present invention;

Fig. 2 is an enlarged sectional view taken alon the line 11-11 of Fig. 1;

Fig. 3 is a longitudinal sectional view similar to Fig. 1 illustrating the governor in its position at full rated load;

Fig. 4 is a longitudinal sectional view through a governor embodying a modified form of the invention illustrating the various parts in their position at maximum governed speed with no load on the engine;

Fig. 5 is a view similar to Fig. 4 illustrating the parts in their position at full rated load;

Fig. 6 is a view taken along the line VI-VI of Fig. 4; and

Fig. 7 illustrates typical performance curves of an engine provided with a governor of this invention in contrast to an engine provided with a conventional governor.

ders upon each stroke of the plungers. plunger is provided with a gear i3.meshing with and rotated by movement of a rack bar |4 extending ,through and supported for reciprocation 1n the housing It). 'One end of the rack bar is piv-:

,otally connected to a link I which in turn is pivotally connected to a lever I6, pivotally supported from a bracketll extending from a suitrotary movement of plungers l2 operates to vary the quantity of'fuel delivered to the engine cylinis accomplished by rocking the control lever 4| aboutits piv'otal. support causing the pin 33 to slide within the s'lot=34, as well as sliding within the slots 39 within the arms 49. Movement of the pin 33 within slot 34 changes the point of application of the force exe'rted'by the governor spring 28 on the lever 35, thus changing the lever ratio of the spring force acting on the rack bar Each able engine'housing or the like indicated at l8.

A vroller I9 is carried for rotation in the opposite end of the lever and is adapted to engage a flanged sleeve 20, supported for rotation as well as sliding movement on an extending end 2| of an engine camshaft 22. The camshaft 22 is provided with a collar 23 having a pair of extending ears 24 which serve as the pivotal support for a pair of flyweights 25. The flyweights are provided with inwardly extending fingers 26 adapted to engage the flanged end of the sleeve 20. During operation of the engine, the flyweights tend to swing outwardly urging the collar to the right, as viewed in Fig. 1, thus moving the lever l6 and rack bar l4 in a direction to decrease the amount of fuel metered to the engine.

Movement of the rack bar H in a direction to decrease the fuel is opposed by a governor spring 28, enclosed within a housing 29, secured to the fuel pump housing as by cap screws, one of which is illustrated at 3|. ,pne end of the spring 28 is pivotally connected to an anchor 32 extending from the housing 29 and itsopposite end is connected to a pin' 33' attending through an elongated slot 34 formed in a lever 35. One end of the lever 35 is pivotally supported from the housing 29 by means of a shaft 36 and its opposite end is pivotally connected to a link 31, which in turn is pivotally connected to the rack bar l4. The force exerted by the spring on the lever 35 urges it to pivot in a counter-clockwise direction, as viewed in Figs. 1 and 3, about the shaft 36, moving the rack bar in a direction to increase the quantity of fuel metered to the engine in opposition to the action of the flyweights. Movement of the rack bar in a direction to increase the amount of fuel metered to the engine is lim-' .ited by a pair of lock nuts 38 threaded on the rack bar l4 and adapted to abut the housing 29 in the maximum fuel position, thus limiting the maximum power output of the engine.

Asis best illustrated in Fig. 2, the pin 33 also extends through a pair of elongated slots 39, one of which is provided in each of a pair of arms 49 forming a part of a bifurcated control lever 4|. The pin is held against axial movement within the slots by an enlarged head 42 formed on one end and by a washer 43 and cotter pin 44 associated with the opposite end. The lever 4| is pivotally supported from the housing 29 by means of pins 45, one of which is received in a suitable opening provided in each of the arms 40. The lever 4| extends through a slotted opening 46 (Fig. 1) provided in the housing 29 and at its extending end is pivotally connected to a control rod, a part of which is illustrated at 41 which may extend to any suitable manual control mechanism (not shown).

Selection of the governed speed of the engine I4, in opposition weights. I i

The governor spring is preloaded an amount determined by thev maximum governed speed of the engine at the time of assembly. Its length,

and as'a result the force exerted by it on the lever 35, remains substantially constant throughout the no load governed speed of the engine as, during changes in the governed speed of the engine, the spring is rocked about its pivotal connection to the governor housing. As a result, the spring is always deflected sufficiently to insure full travel of the rack bar at any governor setting. A second spring 48 is also pivotally connected at one end to the pin 33 and at its opposite end to a pin 49 disposed within an elongated slot 59 provided in a plate member 5| adjustably secured to the housing 29 as by cap screws 52. Under normal operating conditions, the spring 48 is free to follow the action of the governor spring 28 until the pin 49 reaches the end of the slot 50. At this time, further movement of the rack bar H in a direction to increase the amount of fuel supplied to the engine is opposed by the pin 49 engaging the end of the slot 59, thus establishing a so-called rated load for the engine. However, when an additional load is placed on the engine decreasing its speed, the spring 48 will be deflected by the governor spring permitting further movement of the slide bar M in a direction to increase the supply of fuel to the engine until the stop nuts 38 abut the housing 29. This increased amount of fuel results in greater engine torque and may be adjusted to give the particular torque characteristics desired. As the spring 48 is pivotally connected to the pin 33, rocking of the control lever 4| causes the spring 48 also to rock about the pin 49 in the same manner as the governor spring. Thus, at lower governed speeds, a lesser deflection of the torque spring 48 is required to achieve full travel of the rack bar due to the change in the lever ratio.

In operation, selection of the governed speed of the engine is accomplished by rocking the control lever 4| about its pivotal support causing the pin 33 to slide within the slot 34 of lever 35. In Fig. 1, the various elements of the governor are illustrated in the positions they will assume at maximum governed speed with no load on the engine. At this time, the pin 33 is at the lower end-of the slot 34 in lever 35, thus the force of the spring 28 is acting with the greatest lever ratio against the force of the flyweights. When a load is applied to the engine, decreasing its speed, the force exerted by the flyweights will become less permitting the governor spring to move the rack bar M in a direction to increase the quantity of fuel supplied to the engine. During this time, the spring 48 and pin 49 are free to follow the action of the governor spring until the pin reaches the end of the slot 50, as is illustrated in Fig. 3. It is to be noted that in this position of full rated load" that the stop nuts 38 are spaced from the housing 29. Upon increasing the load on the engine, the action of the governor spring causes the spring 48 to be deflected until such time as the to the force exerted by the fly- The phantom lines in Fig.u.3 illu "various elements of the'governor at rated load .same manner as )previously described. However, due to the decreased lever ratio, a lesser de-' 1 flection of the spring 48 will be required to per limiting the Iock nutS-QB abut the housing thus maximum output of the engine.

' s tra te the at a lower governed speed. -By rockingthe lever.

ll 'in a clockwise direction, the effective force exerted by the" governor spring in opposition ,to

the flyweights will be less due to the decreased lever ratio, thus establishing a lower governed 1 speed. of the engine. At this lower governed speed setting, the governor willfunction in the mit the rack bar l4 to'be moved from its position l at rated load, such .as illustrated, to its maximum lustrate the engine torque versus speed performance of an engine provided with thus improved governor at various governed speeds. The dotted lines illustrate the performance of the same engine provided with a conventional governor in which the force of the governor spring opposing the flyweights is varied by changing the load and deflection of the spring. It is to be noted that the solid lines from no load to full engine torque are essentially parallel, however, in the no case of the engine employing a conventional governor represented by the dotted lines, the slope of the curve from no load to full engine torque becomes less as the governed speed of the engine is decreased. This characteristic is 35 the result of decreasing the load and deflection of the governor spring to achieve a lower governed speed. 'By decreasing the load on the govemor spring, at a certain point there will be insufficient deflection applied to the spring to 40 move the fuel control member to its fully opened position within the operating range of the engine. Such a condition is illustrated by the 800 and 600 R. P. M. curves of the conventional govemor.

Figs. 4, 5 and 6 illustrate a modified form of the governor just described in which the basic principleof operation is essentially the same. In Fig. 4, the governor "is illustrated as comprising a pair of flyweights 55 pivotally supported on pins 56, each of whichextends across a slot 51 provided in a collar 58. The collar 58 is carried for rotation on a shaft 59 extending from and supported by a wall of a housing 6| enclosing the mechanism. The collar 58 is provided with an *ztegral gear portion 62 which meshes with and is rotated by a gear 63 carried on the end of an engine camshaft or the like illustrated at 64.

The flyweights are provided with inwardly extending fingers 65 adapted to engage the flanged end of a sleeve 66 carried for rotation. as well as sliding movement on the extending end of the shaft 59. At its opposite end, the sleeve 86 carries a bearing 61, the outer race of which carries a thrust disc 58. The disc 88 is adapted to abut a pair of spaced thrust blocks 89, pivotally supported on a pin H extending from and rigidly secured to a lever 12. The lever I2 is pivotally supported from the housing 6| by means of a pin I3 and at its uppermost end is 70 pivotally connected to a link 14. The link 14 extends through a suitable aperture provided in the housing BI and is pivotally connected as by a pin 15 to the rack bar I4, illustrated in Fig. 1 as controlling the quantity of fuel supplied to 78 the engine. During engine operation, the fly weights-swing outwardly urging the lever 12 to 'rotatein a counter-clockwise direction as viewed in Fig. 4, thus moving the link 14 and rack bar l4 in a direction to decrease the amount of fuel metered .to the engine. I

The force exerted by the flyweights on, the lever 121s opposed by a governor spring 16, one end of which is pivotally connected to an ear 11 extending from thehousing GI and its opposite end to a lever 18. The lever'18 is provided with a cam like surface 19. adapted to engage a roller 8| carried for rotation on the pin'-|l' extendingfrom'the lever, 12 The roller .is interposed between the thrust blocks 69 and separated therefrom by a pair of washers 82. The opposite end of the lever .18 is'pivotally supported ona shaft 83 carried in a pair of spaced

arms

84 and 85, non-rotatably carried on a shaft-86, extending through and supported for rotation in the housing 8 I. At its outer end, the shaft 86 carries a lever 81 clamped thereto by means of a cap screw 88 and its opposite end is pivotally connected to a link 89 which may extend to any suitable manual control mechanism (not shown). 1

The governor spring 16 is preloaded at assembly an amount determined by the maximum governed speed of the engine. The force exerted by' it urges the levers l8 and 12 to rotate in a'clockwise direction, as viewed in Fig. 4, moving the rack bar l4 in a direction to increase the amount of fuel supplied to the engine. Selection of the governed speed of the engine is accomplished by rocking the saft 86 in the housing 8| causing the arms 84 and to swing through an arc moving the lever 18 relative to the roller 8|. This results in a change in the lever ratio of the spring force acting on the lever 18 to the force exerted by the flyweights acting on the lever 18 at an intermediate point through the roller 8|. Rotation of the shaft 86 in a clockwise direction increases the lever ratio resulting in an increase in the governed speed of the engine while rotation in a counter-clockwise direction results in a decreaseed governed speed of the engine.

The shape of the cam surface 19 is such that during movement of the lever 18 relative to the roller 8|, the end of the lever connected to the governor spring will move through an are maintaining a constant spring length. As a result, the force exerted by the spring on the lever is substantially constant throughout the no load speed range of the engine. However, the particular shape of the cam surface may be varied to give any desired governor characteristics.

Rotation of the shaft 88 in a direction to increase the governed speed of the engine is limited by engagement of the arm 85 with a cap screw 9! having a threaded engagement with pin 92 extending from the housing 6|. The cap screw 9| is adjustable to establish the maximum no load" governed speed of the engine and is retained in its adjusted position by means of a lock nut 93. Rotation of the shaft 86 in a direction to decrease the governed speed of the engine isIimited-by engagement of the arm 84 with a spring loaded plunger 94 disposed within a suitable socket 95 threaded into the housing 6|. Engagement of arm 84 with plunger 94 establishes the lowest idling speed of the engine and prevents the operator from inadvertently stalling it. When it is desired to completely shut off the supply of fuel to the engine, the plunger may be depressed permitting the arm 84 to engage a pin 98 carried by the end of the lever 12. Engagement of the arm 84 spring abuts the housing 6|.

with'pin 1.98 establishes a positive mechanical in the connection between the baritmoving it'to the connection with the rack fuel shut on position,

Fig. 4 illustrates the various elements of the governor in the position they would assume at I maximum governed speed with no load on the engine," Asthe engine is loaded, decreasing its speed, the force exerted by the flyweights will become less permitting the governor spring to move the-fuel pump control member toward the increased fuel position. pump control member toward the increased fuel position is limited by apair of nuts 91 carried on the link 14 and adapted to engage a leaf spring 98 rigidly secured to the housing 6| by means 01' cap screws 99. The spring is spaced from the housing by means of a spacer I00 and serves as a resilient stop to establish a rated load" position of the rack bar It below its maximum open position. When the engine is loaded in excess of its rated load, the spring 98 is deflected permitting further movement of the rack bar to increase the fuel supplied to the engine until the The position the various elements assume at maximum governed speed and rated engine load is illustrated in full lines in Fig. 5. The phantom lines illustrate the position of the elements at rated load at a lower governed speed setting.

We claim:

1. In an engine governor, a fuel control member, engine actuated centrifugal fiyweights acting on said member to move it toward low fuel position, a governor spring opposing the action of the flyw'zights and connected with said member to urge it toward full fuel position, a lever included a'msa'raa Movement of the fuel member; an adjustable spring. anchor on said" lever to vary the eifective'force of the spring, a

second spring connected, to the adjustable anchor at one end to oppose the action of the governor spring,'and a'sliding anchor for the other end of the second spring 'with stop means to render the spring effective only when said member 843- "preaches-full fuel position.

2. In an engine governor, a fuel control member, engine actuated centrifugal flyweights actspring and said ing on said member to move it toward low fuel positioma' governor spring opposing the action of the flyweights and, connected with said member to urge it toward full fuel position, a leverincluded in the connection between the spring v and said member, an adjustable spring anchor on said lever to vary the effective force of the spring, a second spring connected to the adjustable anchor at one end to oppose the action of the governor spring, and a sliding anchor for the other end of the second spring with stop means to render the spring efiective only when said member approaches full fuel position and a manually actuated control forvarying the position of said adjustable spring anchor.

GEORGE B. GRIM. KENNETH J. FLECK.

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

UNITED STATES PATENTS Number