US3916862A

US3916862A - Torque rise limiting device

Info

Publication number: US3916862A
Application number: US409864A
Authority: US
Inventors: Jerry A Clouse; John H Parks; Millard D Potter
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1973-10-26
Filing date: 1973-10-26
Publication date: 1975-11-04
Anticipated expiration: 1992-11-04
Also published as: JPS5073031A

Abstract

A torque rise limiting device, for an internal combustion engine having a speed responsive governor adapted normally to urge a fuel control member toward an increased fuel position when the load on the engine is increased, is responsive to a conditional change of the governor when the speed of the engine decreases below a predetermined speed due to a load imposed thereon automatically to move the fuel control member toward a decreased fuel position so that the volume of fuel directed to the engine is reduced for minimizing noxious exhaust emissions therefrom.

Description

United States Patent Clouse et al. Nov. 4, 1975 TORQUE RISE LIMITING DEVICE 3,777,730 12/1973 Gates et al. 123/140 R 1751 Jerry cme, Washington; John 233331233 3/1333 2Z.f......1111111:11311:1113: iii/118E Peona; Millard Ptttter, 3,814,072 6/1974 Gillespie 123 140 R Bartonville, all of III. FOREIGN PATENTS OR APPLICATIONS [73] Ass'gnee' caterp'nar Tractor peona 1,197,274 7/1965 Germany 123/140.1 [22] Filed: Oct. 26, 1973 Primary ExaminerCharles J. Myhre [21] Appl' 409864 Assistant Examiner-Paul Devinsky Attorney, Agent, or Firm-Ralph E. Walters [52] US. Cl. 123/140 MC; 123/140 FG; 123/140 R [51] Int. Cl. F02D l/04; FO2D H06 [57] ABSTRACT [58] new of Search 123/140 J1 140 140 A torque rise limiting device, for an internal combus- 123/140 R tion engine having a speed responsive governor adapted normally to urge a fuel control member [56] References and toward an increased fuel position when the load on UNITED STATES PATENTS the engine is increased, is responsive to a conditional 2,868,184 1/1959 MOUIIOII 123/140 FG Change Of the governor when the speed of the engine 3,107,483 10/1963 I-Iamilton..... 123/140 C decreases below a predetermined speed due to a load 3,145,702 8/1964 Parks 123/140 R imposed thereon automatically to move the fuel con- 3,234,927 1966 Cramer 140 R trol member toward a decreased fuel position so that g p t 1 2 30 1 42)? the volume of fuel directed to the engine is reduced ny ereta.... 3,640,258 M1972 lsobe et a1 123,140 F0 for minimizing noxious exhaust emissions therefrom. 3,707,144 12/1972 Galis et a1. 123/140 R 18 Claims, 7 Drawing Figures WI 3 q 46 Kg 47 5e 26 u I 3 1. arms? ,V 88 .wtw si l6 id's 2 1' 53 28 3 O I 21 I? a 36 29 has fi R '8 1 l9 US. Patent 'Nov. 4, 1975 Sheet 1 of 3 3,916,862

US. Patent Nov. 4, 1975 Sheet 2 of3 3,916,862

TORQUE RISE LIMITING DEVICE BACKGROUND OF THE INVENTION Conventionally, governors are utilized to position a fuel pump feed rack of a compression ignition engine normally to maintain the engine speed within a predetermined operating range. Such governors are shown in US Pat. Nos. 3,145,624 and 3,532,082 issued to Parks et al. and Clouse et al.; respectively, both of which are assigned to the assignee of the present application. With such governors, when the load of the engine is increased the engine speed tends to decrease and the fuel rack is advanced to supply more fuel to the combustion chambers of the engine. When the load on the engine decreases, engine speed increases and the fuel pump feed rack is automatically retracted to reduce the supply of fuel to the engine.

A fixed, full load rack stop is normally provided to limit the maximum volume of fuel directed to the engine for establishing the full load speed of the engine. When the engine is operating at the full load speed and a greater load is applied to the engine, the engine speed will decrease rapidly toward a lug condition. However, the efficiency of the fuel pump increases as the engine speed decreases and a greater volume of fuel is delivered to the combustion chambers resulting in an inherent increase in the brake means effective pressure (BMEP) and the torque of the engine. In some engines, particularly turbocharged engines, the natural torque rise under'such conditions is detrimental to effective control of noxious exhaust emissions from the engine. When the torque rise is too great, inefficient and incomplete buming of fuel results in excessive engine heat and an increase in the exhaust smoke.

OBJECTS OF THE INVENTION Accordingly, an object of this invention is to provide an improved torque rise limiting device for an internal combustion engine.

Another object of this invention is to provide such a torque rise limiting device which limits the amount of torque rise experienced by the engine when its speed is decreased below a full load speed when a lug producing load is imposed on the engine. I

Another object of this invention is to provide an improved torque rise limiting deviceof the character described which automatically decreases the volume of fuel directed to the engine when the engine speed decreases below a predetermined full load speedsetting due to a load imposed thereon to minimize the noxious exhaust emissions from the engine.

Other objects and advantages of the present invention will become more readily apparent upon reference to the accompanying drawings and following description. i v I BRIEFDESCRIP'IION OF THE DRAWINGS FIG. 4 is a longitudinal vertical sectional view of an alternate embodiment of the torque rise limiting device DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring more particularly to FIGS. 1 and 2 of the drawings, a torque rise limiting device embodying the principle of the present invention is generally indicated by the reference numeral 10 in association with a speed responsive governor 11 of an internal combustion engine, not shown. The governor is generallyof the type described in detail in the above cited patents to Parks et al. and Clouse et al. and is contained within a housing 12. The housing includes a generally vertical wall 13 having a pair of spaced generally

parallel bores

14 and 15 formed therethrough. I

The governor includes a pair of substantially L- shaped flyweights l6 pivotally mounted on a rotatable carrier, not shown. Each flyweight has a radially inwardly extending arm.l7 adapted to contact a thrust member 18 mounted on a cylindrical sleeve W. sleeve extends within a bore 20 of a cylindrical collar 21 and is secured to the collar and a fuel control member or rack 22 with a pin 23. The'collar includes an end wall 24 having a centrally disposed bore 25 extending axially therethrough. A bifurcated throttle control lever 26 is pivotally mounted on a shaft 27 secured within the housing 12. The throttle control lever is adapted for engagement with a spring retaining seat 28 which is disposed in concentric axially slidable relation on a support member 29. The support member is fixedly secured to the housing wall 13 in substantially coaxial alignment with the bore 14 and includes a concentric axial bore 31 extending therethrough. A governor spring 32 is concentrically disposed in a precompressed condition between the retainer seat and the collar.

The torque rise limiting device 10 of the present invention includes a hydraulic reaction or servo mechanism 34 reciprocably mounted within the bore 15in the wall 13 of the housing 12. An annular groove 36 is formed in the bore, and is adapted to receive pressurized oil from an engine oil pump, not shown. The servo mechanism includes a hollow cylinder 37 slidably disposed within the bore 15. The cylinder has a coaxial bore 38 and includes a closed end 39 which is disposed adjacent to the control lever 26. An exteriorly extending protuberance 40 is centrally formed on the closed end of the cylinder. An orifice 41 extends radially through the wall of the cylinder adjacent the closed end thereof to communicate the bore of the cylinder with the groove. A cap 42 is screw threadably secured to the open end of the cylinder and has a centrally disposed bore 43 and a plurality of angularly spaced apertures 44 extending therethrough. A slotted tangportion 46 is provided on the end cap for slidably embracing an enlarged shank 47 of a guide member 48 which is screw threadably secured to the wall adjacent to the cylinder.

A-piston 49 is reciprocably mounted within the cylinder 37 and has a medially disposed annular wall 51 forming within the cylinder a pair of axially spaced chambers 52 and 53. A centrally disposed aperture 54 extends axially through the annular wall to provide communication; .between the chambers. A pair of

springs

56 and 57 are individually disposed within the chambers on opposite sides of the piston and act in op- :posite directions normally to center the piston within the cylinder. A bleed valve 58 is partially disposed within the chamber 52 and has a reduced diameter guide and actuation portion 59 slidably extending through the central bore 43 of the cap 42. A recess 61 is provided in the end of the bleed valve adjacent to the annular wall and is formed in part by anannular axially extending .valve seat 62. The valve seat is adapted for selective sealing engagement with the annular wall to block communication between the chambers 52 and 53 through-the aperture54.

A lever 63 is secured to the free end of a leaf type spring 64 which is in turn secured by a capscrew 65 to the wall 13 of the housing 12 to permit limited pivotal :movement of the lever. The lever extends upwardly therefrom and includes a distal or free end 66 which'is adapted for abutment with the guide portion 59 of the bleed valve 58. A pair of generally vertically spaced

clearance holes

67 and 68 are provided in the lever intermediate itsends.

An elongated sensor and actuator member 69 is slidably disposed within the bore 31 of the support member 29. An end 71 of the member extends through the bore 25 in the end wall 24 of the collar 21 and has an enlarged flange 72 formed thereon for unidirectional force transmitting engagement with the end wall. An opposite end 73 of the actuator member extends through the bore 14 of wall 13 and the hole68 of the lever 63 and includes a circumferential groove 74 fomied therearound. A bracket 76 includes a through bore 77 which is slidably received on the end 73 in radiably embraces a rod 87 secured to the housing 12 for preventing rotation of the bracket and the actuator member. I g

A cam 88 is secured between the bifurcated-portions of the control lever 26 for rotation therewith and has a cam lobe 89 formed thereon for engagementwith the protuberance 40 of the cylinder 37.

Modified First Form A modification of the above embodiment is shown in FIG. 3 and includes an inwardly opening hole 90 which is formed in the closed end 39 of the cylinder 37 and is concentric with the bore 38. An elongated stop pin 91 is pressed into the hole and has an enlarged head portion 92 in abutment with the annular wall 51 of the piston 49. A recess 93 and a plurality of radially extending slots 94 are formed in the head portion adjacent to the annular wall for communicating the chamber 53 with the aperture 54 in the annular wall. The length ofv the pin is selected to position the piston slightly to the left bf its position in FIG. 1 to unbalance the

springs

56 and 57 with spring 56 having a greater preload than the spring 57.

- Another modification which may be made to the above embodiments is that by employing the stop pin in the chamber 53, the spring 57 in the chamber 53 can be deleted. However, the spring rate of the spring 56 in the chamber 52 and the cross sectional area of the bleed valve 58 may require slight adjustments to obtain the same torque rise as the previous embodiments.

Operation of First Form While the operation of the present invention is believed clearly apparent from the foregoing description, further amplification will subsequently be made in the following brief summary of such operation. The governor 11 functions to maintain the engine speed within a predetermined operating range by adjusting the position of the fuel control member 22 in the usual manner as the load on the engine varies. The predetermined speed range is established by manual positioning of the throttle control lever 26 to provide a preload force on the governor spring 32 to act against the centrifugal force of the flyweights 16. Rotating the control lever in a counterclockwise direction results in movement of the fuel control member to the right to increase the volume of fuel injected into the engine to increase the engine speed. Clockwise rotation of the lever results in moving the fuel control member to the left to reduce the supply of fuel to the engine to decrease enggfie speed. When the desired speed of the engine is tained, the centrifugal force on the flyweights exertsan axial force through the arms 17 to counterbalance the axial force of the governor spring, thus establishing an instantaneous position of the fuel control member.

When the load on the engine is increased, engine speed decreases resulting in a corresponding reduction in the axial force of the flyweights 16 thereby allowing the governor spring 32 to move the fuel control member 22 to the right for supplying more fuel to the engine ,to maintain the engine speed within the desired range.

During normal engine operation, with the throttle control lever 26 in its maximum engine speed setting as shown in FIG. 1, and the engine lightly loaded, the engine runs at the high idle speed. As shown in FIG. 7, the torque curve of an engine embodying the present invention is shown by the solid line curve indicated by the letter A with the torque at high idle speed indicated at point B. Pressurized engine oil is directed to the groove 36 in the bore 15 of the housing 12 and through the orifice 41 of the cylinder 37 into the chamber 53. The pis- 69 moving it and the bracket 76 to the right. At a pre-' determined position, thespherical end 83 of the stop member 82 engagesthe lever 63 causing its distal end 66 to engage the bleed valve 58. This moves the bleed valve to the right until the valve seat 62 restricts the flow of engine oil through the aperture 54 sufficiently to cause a pressure rise in the oil in the chamber 53. At

this point, the pressurized fluid acting on the bleed valve creates a force thereon acting against the distal end of the lever sufficient to balance the force of the governor spring 32 thereby stopping" the rightward movement of the fuel control member thus establishing the full load speed condition of the engine. The torque of the engine at the full load speed is indicated at point C in FIG. 7. The torque curve up to this point is identical with that of an engine without the present invention.

As the. load on the engine continues to increase above the normal operating range, engine speed drops and the centrifugal force of the flyweights 16 acting on the governor spring 32 also decreases. This causes the governor 11 to become imbalanced such that the governor spring force urges the collar 21, actuator member 69, lever 63, and the bleed valve 58 to the right. This is effective to move the bleed valve to the right until the valve seat 62 blocks the flow of oil through the aperture 54 of the piston 49. The resultant increase influid pressure in the chamber 53 causes the piston and the bleed valve to move to the left against the distal end 66 of the lever causing it to rotate counterclockwise with the spring 64 acting as a pivot. This moves the actuator member, collar, and the fuel control member to the left to decrease the volume of fuel directed to the engine thereby decreasing the rate of torque rise of the engine.

The leftward movement of the piston 49 continues until an imbalance between the

springs

56 and 57 and the increasing bias of the governor spring 32 equal or balances the hydraulic force acting on the piston. At this point, fluid pressure acting on the recess.61 of the bleed valve 58 is sufficient to unseat the valve seat 62 permitting fluid flow through the aperture 54. However, the valve seat will meter the fluid flow and maintain sufficient pressure in the chamber 53 to retain the piston in its new position. If the load on the engine increases sufficiently, the engine speed will drop to its lugging speed with a proportionate decrease in the volume of fuel directed to the engine. Referring to FIG. 7, the torque at the lugging speed is indicated at point D and the amount of torque rise between the full load speed and the lugging speed is represented by the portion of the solid line curve A between points C and D. By comparison, the natural torque rise of an identical engine without the torque rise limiting device is represented by the broken line curve indicated at B.

When the engine is running at a lugging speed below the full load speed, the piston 49 and fuel control member 22 will be positioned to the left of that shown in FIG. 1 as described above. Should the throttle control lever 26 be rotated clockwise under such conditions, the force exerted on the bleed valve 58 by the governor spring 32 would be lessened. Reducing the force on the bleed valve permits an instantaneous greater volume of oil to flow past the valve seat 62 from the chamber 53 reducing the pressure therein such that the piston moves toward the closed end 39 of the cylinder until the forces of the

springs

56 and 57 and the governor spring acting on the bleed valve and piston are again balanced by the hydraulic force as described above. To compensate for such occurrence and prevent movement of the fuel control member toward the increased fuel position, the cylinder is moved to the left by the cam lobe 89 as the throttle control lever is rotated clockwise. The change in the imbalance of the

springs

56 and 57 balances the changing force of the governor spring such that the piston remains substantially stationary relative to the wall 1 3 Thl 1S the position of the fuel control member is virtually unaffected by the repositioning of the throttle controllever when the engine is operating at lugging speeds below the full load speed.

With the engine being operated at an intermediate throttle setting and the engine lightly loaded, the throttle control lever 26 is positioned clockwise from its maximum throttle setting. Likewise, since the cam 88 is secured to the throttle=control lever and rotates there with, the cylinder 37 will. be'repositioned to the left of that shown in FIG. 1 by the cam lobe '89. Thus, as the fuel control member is moved to the right by the governor 11 under increasing engine loads, the lever 63 engages the bleed valve 58 earlier and stops the fuel control member in a predetermined position farther to the left than when the throttle control lever is in the maximum throttle setting. This establishes a full load speed relative to the throttle control lever setting and prevents overfueling during luggingof the engine at an intermediate throttle settingflThus, the torque rise limiting device is effective through thelentire range of throttle settings and engine speedsThe torque rise curve for an intermediate throttle control lever setting is shown at F in FIG. 7 with the curve joining the torque curve A at point G and continues to increase along the curve A to point D. By contrast, the torque curve of the engine without the present invention coincides with curve F with the torque continuing to increase past point G and joining the broken line curve E at point H. The horsepower curve for the engine is represented by the line indicated by the letter J.

Operation of Modified First Form The operation of the modification of the torque rise limiting device 10 shown in-FIG. 3 is essentially as described above except that there is provided a greater preload in the spring 56 with the pin 91 causing a slight delay in the reaction of the servo mechanism 34. As in the first form, the bleed valve 58 is moved to the right under increasing engine loads until the fluid pressure in the chamber 53 acting on. the bleed valve creates a force thereon sufiicient to balance the force of the governor spring 32. At this point, the rigthward movement of the fuel control member 22 toward the increased fuel position is stopped establishing the full load speed condition of the engine. It is 'to be assumed that the stop member 82 has been adjusted to compensate for the slightly leftward positioning of the piston 49 so that the full load speed and thus, the torque, is the same as that established for the first form. i

As the engine speed continues to drop due to increased loading, the governor spring 34 exerts a greater force on the bleed valve SS'which in turn causes the fluid pressure in the chamber 53 to increase. However, until the force exerted on the piston 49 by the pressurized fluid in the chamber, combined with the force of the spring 57, increases sufficiently to overcome the preload of the spring 56,the piston 49 will remain in abutment with the pin 91. Thus the fuel control member 22 will temporarily remain in the maximum fuel position and the engine torque will increase from point C in FIG. 7 along the broken line E. At a predetermined point K, the force exerted on the piston by the fluid and the spring 57 overcomes the:preload of the spring 56.

As this occurs the piston moves to the left resulting in movement of the fuel control member to the left toward a decreased fuel position for controlling the torque rise of the engine with the torque being repre- 7 sented by the phantom line-"L extending from point K. $h m An alternate embodiment of a torque rise limiting device of the present invention is disclosed in-FIGS. 4, and 6. It is noted that the samereference numeralsof the first embodiment are used to designate similarly constructed counterpart elements of this embodiment. In this embodiment, however, the torque rise limiting device is mechanically actuated with the sleeve 19 being slidably disposed in the bore 20 of the collar 2-1. A pair of elongated slots 96 are provided in the collar individually to receive the ends of the pin 23 for permitting limited relative axial movement between the sleeve and the 'collar. A keeper band 97 encircles the collar to prevent dislodgement of the pin. The sleeve includes a reduceddiameter end portion 98 extending toward the end wall 24 of the collar. Aconcentric axially extending bore 99 is provided in the reduced diameter portion and terminates at an end wall 101 having a central aperture 102 extending therethrough. A ring 103 is disposed within the bore 20 of the collar with a spring 104 concentrically disposed between thejring and the sleeve and preloaded to a predetermined value for resiliently urging the sleeve and collar inopposite directions.

The torque rise limiting device of the alternate embodiment includes a mechanical reaction mechanism 106 which includes an adapter 107 disposed adjacent to the wall 13 of the housing 12. The adapter has an annular extension 108 slidable within the bore of the wall. An aperture 109 is provided in the adapter and slidably receives a shank 110 of a guide member 111 screw threadably secured to the wall to prevent rotation of the adapter. A threaded bore 112 is provided through the annular extension for receiving an adjustable stop member 113 adapted for engagement with the cam lobe 89 of the control lever 26.. The adapter further includes a depending stop portion .114 for a later defined purpose. M v

A sensor tube 116 is reciprocably disposed in the bore 31 of the support member 29 and is provided with I an axial bore 117 which slidably receives an elongated actuator rod 1 18. The actuator rod extends through the aperture 102 in the end wall 101 of the sleeve 19 and has an enlarged head portion 1 19 formed on its end for unidirectional force transmitting engagement with the end wall of the sleeve.

' The bracket 76 secured to the end 73 of the sensor tube 116 has an inner surface 121 disposedadjacent to the wall 13 of the housing 12 and an opposite outersur- 1 face 122. A recess 123 is formed in the inner surface to provide clearance for the stop portion 114 of the adapter 107 disposed between the bracket and the wall. A pair of spaced lugs 124 are fixedly secured to the outer surface 122 and extend outwardly therefrom. A bore 126 extends though the bracket in spacedsubstantially parallel relation to the bore77. A pin 127 slidably extends through the bore 126 for engagement with the stop portion of the adapter and has a spherical head is formed on the side of the lever intermediate the pivot pin and slot and is adapted for engagement with the spherical head 128 of the pin 127. An adjustment screw 137 is screw threadedly secured to the proximal end of the lever and has a jam nut 138 provided thereon for locking the adjustment screw in the ad- FIGS. 4, 5 and 6 operates the same asthat described above in connection with the first form in that when the load on the engine is increased the fuel control member 22 is normally adjusted to the right by the governor for supplying more fuel to the engine to maintain the engine speed within the desired operating range. The torque rise limiting device and the governor are shown in thefull load speed condition in FIG. 4 with the fuel controlmember 22 in a position for supplying a predetermined maximum volume of fuel to the engine. At engine speeds between the highidle and full load speed, the fuel control member, the collar21, and the sleeve 19 arepositioned slightly to the left of that shown in FIG. 4 such that the head 119 of the actuator rod 118 is spaced somewhat from the end wall 101 of the sleeve and the enlarged flange 72 of the sensor tube 116 is spaced somewhat from the end wall 24 of the collar. Under such conditions the governor 11 operates in the usual manner.

With the control lever 26 in the position shown and the engine lightly loaded, the engine is set to operate at the high idle speed. Increasing the load on the engine results in the governor 11 moving the collar 21, sleeve 19, and fuel control member 22 to the right to increase the volume of fuel to the engine as previously described. At a predetermined speed, the end wall 24 of the collar engages the enlarged flange 72 of thesensor tube 116 and the end wall 101 of the sleeve 19 engages the head 1 19 of the actuator rod 1 18. This prevents further rightward movement of the fuel control member and establishes the full load speed condition of the engine. Y

As the load onthe engine is further increased, the engine-speed drops below its full load speed and the centrifugal force of the flyweights 16 acting on the thrust member 18 and collar 2lis reduced permitting the governor spring32 to exert a greater force on the collar.

Thismoves the collar, .the sensor tube 116, and the bracket 76 to the right. The pin 127 abuts the stop portion 114 of the adapter 107 with the spherical head 128 of the pin providing a fulcrum for the lever 129. As the bracket and pin 131 move to the right thelever pivots about the spherical head causing the distal end of ythe lever to be moved to the left. This. results in the actuator rod 118 moving the sleeve 19 and fuel control member 22 to the left against the bias of the spring 104,

thereby reducing the volume of fuel supplied to the engine to control the amount of torque rise of the engine .during lugging. The leftward movement of the sleeve and fuel control member continues until the bias of the spring 104 balances the available forcefrom the govere norspring. .Further reduction in the engine speed as a result of greater loading will consequently result in further leftward movement of the fuel ,control member decreasing the supply of fuel to the engine."

.As .with. t he previous embodimentsthe cam lobe 89 of the cam 88 moves the mechanical reaction mechai 9 nism 106 to the left at intermediate throttle settings. This moves the pin 127 to the left to establish the full load speed condition in accordance with the throttle control lever setting.

The torque rise curve of the engine equipped with the alternate embodiment torque rise limiting device, is identical to that of the first form. However, by increasing the initial preload of the spring 104, the torque of the engine will increase along the broken line E in FIG. 7 until the force exerted by the governor spring 32 becomes sufficient to overcome the preload of the spring 104. At this point, which is represented by the letter K in FIG. 7, the torque rise limiting device becomes effective for controlling the torque rise with the torque being depicted by phantom line L.

In view of the foregoing, it is readily apparent that the structure of the present invention provides an improved torque rise limiting device which limits the rate of torque rise of an internal combustion engine when the engine speed is decreased below its full load speed due to greater loading of the engine thereby reducing the volume of fuel injected into the engine. This permits more efficient and complete combustion of the fuel to minimize the emission of noxious matter from the engine. This is accomplished by automatic movement of the fuel control member to a reduced fuel setting in response to a conditional change of the governor created when the centrifugal force of the flyweights, balancing the force of the governor spring, is reduced to a decrease in engine speed. The torque rise limiting device further automatically positions itself in response to a change in the throttle control lever setting so that the device effectively limits torque rise and minimizes exhaust emissions throughout the full range of throttle settings and engine operating speeds. While the invention has been described and shown.

with particular reference to the preferred embodiments, it will be apparent that variations might be possible that would fall within the scope of the present invention which is not intended to be limited except as defined in the following claims.

I What is claimed is:

1. A torque rise limiting device, for an internal combustion engine having a speed responsive governor adapted normally to urge a fuel control member toward an increased fuel position when the load on the engine is increased, comprising;

sensor and actuator means operatively associated with such governor and such fuel control member initially permitting the fuel control member to be moved toward an increased fuel position by the governor in response to a decrease in engine speed clue to a load imposed thereon; and

reaction means operatively associated with said sensor and actuator means and responsive to a conditional change of the governor transmitted thereto by the sensor andactuator means when the speed of the engine decreases below a predetermined speed due to the load imposed thereon to impart a reaction force through the sensor and actuator .means to reverse the direction of movement of the fuel control member and automatically move the fuel control member toward a decreased fuel position so that the volume of fuel directed to the engine is reduced for limiting the natural torque rise thereof and minimizing noxious exhaust emissions therefrom.

- 10 2.The torque rise-limiting device of claim 1 wherein the governor includes;

a housing;

a throttle control lever pivotal within the housing between a minimum and maximum engine speed setting;

a governor spring operatively disposed between said control lever and the fuel control member for resiliently urging the fuel control member toward the increased fuel position; and

a flyweight arrangement responsive to engine speed normally to counterbalance the bias of the governor spring to minimize changes in engine speed due to varying engine loads with said conditional change of the governor causing an actuating force to be exerted on said reaction means by said governor spring through said sensor and actuator means.

3. The torque rise limiting device of claim 2 wherein said reaction means establishes said predetermined speed of the engine and includes cam means associated with said throttle lever for automatically adjustably positioning said reaction means relative to the setting of the throttle control lever for changing said predetermined speed dependent upon the throttle control lever setting with said torque rise limiting device being effective throughout the total range of throttle lever settings.

4. The torque rise limiting device of claim 3 wherein said reaction means includes;

a source of pressurized fluid;

means forming a bore in said housing adjacent to said cam means; and

ahydraulic servo mechanism reciprocably disposed in said bore and in communication with said source of pressurized fluid, said hydraulic servo mechanism having opposite ends with one of said ends adapted for engagement with the cam means while the other of said ends is adapted for engagement with said sensor and actuator means, said hydraulic servo mechanism being operative in response to said actuating force imposed thereon by said sensor and actuator means to generate a reaction force substantially equal to said actuating force with said reaction force being transmitted by the sensor and actuator means to move the fuel control membe toward said decreased fuel position.

5. The torque rise limiting device of claim 4 wherein said sensor and actuator means includes; 5

an actuator member having opposite ends with one of said ends operatively connected to the fuel control member;

a bracket secured to the other end of said ends of said actuator member;

a lever having opposite ends with one of said ends being pivotally secured to said housing while the other of said ends is adapted for engagement with the other end of said hydraulic servo mechanism; and

a stop adjustably secured to the bracket for engagement with said lever intermediate said opposite ends.

6. The torque rise limiting device of claim 5 wherein said hydraulic servo mechanism includes;

a cylinder having an axial bore formed therein, siad bore having an open end and an opposite closed end, and an orifice communicating said bore with said source of pressurized fluid;

a cap secured tosaid open end of said cylinder having a plurality of apertures and a centrally disposed 1 1 bore extending therethrough'with said bore being substantially concentric with said bore of said cylinder;

a piston reciprocably mounted in said bore of said cylinder forming a first chamber between said piston and said closed end for receiving fluid from the source of pressurized fluid, and a second chamber between the piston and said cap, said piston having a centrally disposed aperture extending there- 1 through for communicating the first chamber with the second chamber;

positioning means for initially positioning said piston in said bore of the cylinder including a spring disposed in said second chamber; and

a bleed valve slidably disposed in said bore of said cap and having opposite ends, a valve seat formed on one of said ends normally positioned to permit substantially unrestricted flow through said aperture in said piston and adapted for blocking fluid flow therethrough when said actuating force is exerted in a first direction on the other of said ends of said lever of said sensor and actuator means to generate said reaction force by increasing the fluid pressure in the first chamber to cause the piston to move in an opposite direction until the actuation force on the valve is balanced by the reaction force.

7. The torque rise limiting device of claim 6 wherein said positioning means includes a spring disposed in said first chamber.

8. The torque rise limiting device of claim 6 wherein said positioning means includes stop means associated with said cylinder to limit movement of said piston toward said closed end of said cylinder.

9. The torque rise limiting device of claim 8 wherein said spring in said second chamber is initially precompressed by said piston and said stop means to delay movementof said fuel control member toward said decreased fuel position until the engine speed decreases a preselected amount below said predetermined speed.

10. The torque rise limiting device of claim 9 wherein said stop means includes a stop member disposed .within said first chamber between said closed end and said piston, said stop member having an end portion for engagement with said piston and passage means formed in said end portion for communicating said first chamber with said aperture in said piston.

11. The torque rise limiting device of claim 10 including a spring disposed in said first chamber between said piston and said closed end of said cylinder.

12. The torque rise limiting device of claim 3 includmg; 7 i

a cylindrical collar operatively disposed between the governor spring and the flyweight, said collar having an axially aligned bore formed itlierein and a pair of diametrically opposed elongated slots extending therethrough; a sleeve reciprocably disposed in said bore; an elongated pin fixedly securing said sleeve to the fuel control member, said pin having opposite ends individually protruding into said elongated slots to permit limited relative axial movement betweeri the sleeve and collar; and a spring disposed between the sleeve and collar preloaded to a predetermined value resiliently to urge the sleeve and fuel control member toward said increased fuel position.

13. The torque rise limiting device of claim 12 wherein said sensor and actuator means includes an elongated sensor tube having opposite ends with one of said ends connected to said collar for selective unidirectional force transmitting engagement therewith, said tube having a bore extending axially therethrough; and

an actuator rod slidably disposed in said bore of said sensor tube and having opposite ends with one of said ends having unidirectional driving connection with said sleeve for transmitting axial unidirectional movement thereto.

14. The torque rise limiting device of claim 13 wherein said reaction means includes a mechanical reaction mechanism operatively attached to said sensor tube and to the other of said ends of actuator rod operative in response to said actuating force transmitting thereto by said sensor tube to generate a reaction force in the actuator rod for'moving the sleeve and the fuel control member toward the decreased fuel position against the bias of said spring disposed between said sleeve and said collar until the actuating force is balanced by the bias of said spring.

15. The torque rise limiting device of claim 14 wherein said mechanical reaction mechanism includes an adapter having an annular extension slidably disan end operatively connected to said other end of 7 said actuator rod, said lever having an intermediate portion engageable withthe other of said ends of said fulcrum pin so that movement of the sensor tube and bracket in a first direction causes the lever to pivot about the fulcrum pin to move the actuating rod in an opposite direction.

16. The torque rise limiting device of claim 12 wherein said spring is initially preloaded a preselected amount greater than said predetermined value to delay movement of said fuel control member toward said decreased fuel position until the engine speed decreases a preselected amount below said predetermined speed.

17. A torque rise limiting device for an internal combustion engine having a speed responsive governor adapted normally to urge a fuel control member toward an increased fuel position when the load? on the engine is increased, comprising;

a source of pressurized fluid; and

reaction means including a hydraulic servo mechanismcommunicating with said source of pressurized fluid having opposite ends with one of said ends operatively associated with such fuel control member, said hydraulic servo mechanism initially permitting the fuel control member to move toward an increased fuel position in response to a decrease in engine speed due to a load imposed thereon and being operative in response to a conditional change of the governor when the speed of the engine decreases below a predetermined speed due to the load imposed thereon to generate a reaction force to reverse the direction of movement of 13 the fuel control member and move the fuel control member toward a decreased fuel position so that the volume of fuel directed to the engine is reduced for limiting the natural torque rise thereof and minimrzmg the noxious exhaust emissions therefrom.

18. The torque rise limiting device of claim 17 including sensor and actuator means operatively associmember toward the decreased fuel position.

Disclaimer 3,916,862.Jerry A. Clause, Washington; John H. Parks, Peoria; and Millard D.

Potter, Bartonville, Ill. TORQUE RISE LIMITING DEVICE. Patent dated Nov. 4, 1975. Disclaimer filed Feb. 19, 1982, by the assignee, Caterpillar Tractor Co.

Hereby enters this disclaimer to claim 1 of said patent. [Official Gazette May 4, 1982.]

Claims

1. A torque rise limiting device, for an internal combustion engine having a speed responsive governor adapted normally to urge a fuel control member toward an increased fuel position when the load on the engine is increased, comprising; sensor and actuator means operatively associated with such governor and such fuel control member initially permitting the fuel control member to be moved toward an increased fuel position by the governor in response to a decrease in engine speed due to a load imposed thereon; and reaction means operatively aSsociated with said sensor and actuator means and responsive to a conditional change of the governor transmitted thereto by the sensor and actuator means when the speed of the engine decreases below a predetermined speed due to the load imposed thereon to impart a reaction force through the sensor and actuator means to reverse the direction of movement of the fuel control member and automatically move the fuel control member toward a decreased fuel position so that the volume of fuel directed to the engine is reduced for limiting the natural torque rise thereof and minimizing noxious exhaust emissions therefrom.

2. The torque rise limiting device of claim 1 wherein the governor includes; a housing; a throttle control lever pivotal within the housing between a minimum and maximum engine speed setting; a governor spring operatively disposed between said control lever and the fuel control member for resiliently urging the fuel control member toward the increased fuel position; and a flyweight arrangement responsive to engine speed normally to counterbalance the bias of the governor spring to minimize changes in engine speed due to varying engine loads with said conditional change of the governor causing an actuating force to be exerted on said reaction means by said governor spring through said sensor and actuator means.

4. The torque rise limiting device of claim 3 wherein said reaction means includes; a source of pressurized fluid; means forming a bore in said housing adjacent to said cam means; and a hydraulic servo mechanism reciprocably disposed in said bore and in communication with said source of pressurized fluid, said hydraulic servo mechanism having opposite ends with one of said ends adapted for engagement with the cam means while the other of said ends is adapted for engagement with said sensor and actuator means, said hydraulic servo mechanism being operative in response to said actuating force imposed thereon by said sensor and actuator means to generate a reaction force substantially equal to said actuating force with said reaction force being transmitted by the sensor and actuator means to move the fuel control member toward said decreased fuel position.

5. The torque rise limiting device of claim 4 wherein said sensor and actuator means includes; an actuator member having opposite ends with one of said ends operatively connected to the fuel control member; a bracket secured to the other end of said ends of said actuator member; a lever having opposite ends with one of said ends being pivotally secured to said housing while the other of said ends is adapted for engagement with the other end of said hydraulic servo mechanism; and a stop adjustably secured to the bracket for engagement with said lever intermediate said opposite ends.

6. The torque rise limiting device of claim 5 wherein said hydraulic servo mechanism includes; a cylinder having an axial bore formed therein, siad bore having an open end and an opposite closed end, and an orifice communicating said bore with said source of pressurized fluid; a cap secured to said open end of said cylinder having a plurality of apertures and a centrally disposed bore extending therethrough with said bore being substantially concentric with said bore of said cylinder; a piston reciprocably mounted in said bore of said cylinder forming a first chamber between said piston and said closed end for receiving fluid from the source of pressurized fluid, aNd a second chamber between the piston and said cap, said piston having a centrally disposed aperture extending therethrough for communicating the first chamber with the second chamber; positioning means for initially positioning said piston in said bore of the cylinder including a spring disposed in said second chamber; and a bleed valve slidably disposed in said bore of said cap and having opposite ends, a valve seat formed on one of said ends normally positioned to permit substantially unrestricted flow through said aperture in said piston and adapted for blocking fluid flow therethrough when said actuating force is exerted in a first direction on the other of said ends of said lever of said sensor and actuator means to generate said reaction force by increasing the fluid pressure in the first chamber to cause the piston to move in an opposite direction until the actuation force on the valve is balanced by the reaction force.

9. The torque rise limiting device of claim 8 wherein said spring in said second chamber is initially precompressed by said piston and said stop means to delay movement of said fuel control member toward said decreased fuel position until the engine speed decreases a preselected amount below said predetermined speed.

10. The torque rise limiting device of claim 9 wherein said stop means includes a stop member disposed within said first chamber between said closed end and said piston, said stop member having an end portion for engagement with said piston and passage means formed in said end portion for communicating said first chamber with said aperture in said piston.

12. The torque rise limiting device of claim 3 including; a cylindrical collar operatively disposed between the governor spring and the flyweight, said collar having an axially aligned bore formed therein and a pair of diametrically opposed elongated slots extending therethrough; a sleeve reciprocably disposed in said bore; an elongated pin fixedly securing said sleeve to the fuel control member, said pin having opposite ends individually protruding into said elongated slots to permit limited relative axial movement between the sleeve and collar; and a spring disposed between the sleeve and collar preloaded to a predetermined value resiliently to urge the sleeve and fuel control member toward said increased fuel position.

13. The torque rise limiting device of claim 12 wherein said sensor and actuator means includes an elongated sensor tube having opposite ends with one of said ends connected to said collar for selective unidirectional force transmitting engagement therewith, said tube having a bore extending axially therethrough; and an actuator rod slidably disposed in said bore of said sensor tube and having opposite ends with one of said ends having unidirectional driving connection with said sleeve for transmitting axial unidirectional movement thereto.

14. The torque rise limiting device of claim 13 wherein said reaction means includes a mechanical reaction mechanism operatively attached to said sensor tube and to the other of said ends of actuator rod operative in response to said actuating force transmitting thereto by said sensor tube to generate a reaction force in the actuator rod for moving the sleeve and the fuel control member toward the decreased fuel position against the bias of said spring disposed between said sleeve and said collar until the actuating force is balanced by the bias of said spring.

15. The torque rise limiting device Of claim 14 wherein said mechanical reaction mechanism includes an adapter having an annular extension slidably disposed in said bore of said housing; a stop adjustably secured to said adapter and disposed for engagement with said cam means; a bracket secured to the other of said ends of said sensor tube and having a bore in spaced substantial parallel relation to said sensor tube; a fulcrum pin slidably extending through said bore of said bracket having opposite ends with one of said ends adapted for engagement with said adapter; and a lever pivotally secured to said bracket and having an end operatively connected to said other end of said actuator rod, said lever having an intermediate portion engageable with the other of said ends of said fulcrum pin so that movement of the sensor tube and bracket in a first direction causes the lever to pivot about the fulcrum pin to move the actuating rod in an opposite direction.

17. A torque rise limiting device for an internal combustion engine having a speed responsive governor adapted normally to urge a fuel control member toward an increased fuel position when the load on the engine is increased, comprising; a source of pressurized fluid; and reaction means including a hydraulic servo mechanism communicating with said source of pressurized fluid having opposite ends with one of said ends operatively associated with such fuel control member, said hydraulic servo mechanism initially permitting the fuel control member to move toward an increased fuel position in response to a decrease in engine speed due to a load imposed thereon and being operative in response to a conditional change of the governor when the speed of the engine decreases below a predetermined speed due to the load imposed thereon to generate a reaction force to reverse the direction of movement of the fuel control member and move the fuel control member toward a decreased fuel position so that the volume of fuel directed to the engine is reduced for limiting the natural torque rise thereof and minimizing the noxious exhaust emissions therefrom.

18. The torque rise limiting device of claim 17 including sensor and actuator means operatively associated with such governor and said end of said hydraulic servo mechanism for sensing and transmitting said conditional change of the governor to the hydraulic servo mechanism and being responsive to operation of the hydraulic servo mechanism to move the fuel control member toward the decreased fuel position.