US3640258A

US3640258A - Governor for internal combustion engines of injection type

Info

Publication number: US3640258A
Application number: US60221A
Authority: US
Inventors: Hiroshi Isobe; Hachiro Aoki; Noritoshi Tanaka
Original assignee: Diesel Kiki Co Ltd
Current assignee: Bosch Corp
Priority date: 1969-08-04
Filing date: 1970-08-03
Publication date: 1972-02-08
Anticipated expiration: 1989-02-08
Also published as: JPS4922970B1

Abstract

A governor for an internal combustion engine of the injection type. The position of a fuel rod is controlled by the balance of the opposing forces of the spring and a fluid pressure, the latter varying in response to engine speed. The pressure of this fluid is controlled by a control valve operable in one direction to open a bleed port by the force of fluid pressure and thereby increase fuel supply and operable in the opposite direction by the spring force to close the bleed port and thereby decrease fuel supply. Movement of the control valve in the bleed port closing direction is also caused by either a manually operated lever and/or a lever arm, the latter being operated by centrifugal weights in response to engine speed.

Description

nited States Patent 1151 3,640,258

lsobe et al. Feb. 8, 1972 [54] GOVERNOR FOR INTERNAL 2,292,194 8/1942 Blymer ..123/ 140 X M U ION NG N 013 2,525,653 10/1950 Darnell... ..123/ 140 INJECTION TYPE 3,139,875 7/1964 Link ..123/140 [72] Inventors: Hiroshi lsobe; l-lachiro Aoki; Noritoshi P a E i r Lau n Goodridge Tamika, all of saltamaxjapan Attorney-Larson, Taylor and Hinds [73] Assignee: Diesel Kiki Kabushiki Kaisha, Tokyo,

Japan [57] ABSTRACT [22] Filed: Aug. 3, 1970 A governor for an internal combustion engine of the injection type. The position of a fuel rod is controlled by the balance of the opposing forces of the spring and a fluid pressure, the latter varying in response to engine speed. The pressure of this [30] Foreign Application Priority Data fluid is controlled by a control valve operable in one direction to open a bleed port by the force of fluid pressure and thereby [21] Appl. No.: 60,221

Aug. 4, 1969 Japan ..44/61052 increase fuel Supply and operable in the opposim direction by 52 us. c1. .123 140 FG the Swing fmce bleed Polrt and decrease E51; Int. Cl 1 14211 1/12 fuel P Mmmem the comm valve in the bleed P [581 Field of Search 123/97, 103, 104, 139, 140, closing directiml is also caused by either a manually Operated 1 3/140 FG lever and/or a lever arm, the latter being operated by centrifugal weights in response to engine speed.

561 References Cited 5 Claim 8 Drawing Figures UNITED STATES PATENTS 2,334,340 9/1945 Reggie .123/140 11 2| I50 a 24 22 I6 11 11a 1 7* q s l2 1 J g 23 I 25 25 31 B 2 g 29 a I 7 I 32 38a q GOVERNOR FOR INTERNAL COMBUSTION ENGINES OF INJECTION TYPE This invention relates to a governor for automotive internal combustion engines of injection type.

For automotive governors, it has heretofore been common practice to use maximum-speed minimum-speed centrifugal governors, whose lever reaction force is small. In driving an automobile having its fuel-injection engine equipped with such a speed governor, the driver has to manipulate the accelerator frequently and closely, when his automobile is traveling on a rough road, in order to cope with the wide variations of engine load caused by the high and low spots of the road surface. Such a manner of accelerator control rapidly fatigues the driver. Moreover, in a standing start on a muddy or snow-covered road, the driver has to operate the accelerator deftly so that engine speed will not race up or fall to the stalling level. Thus, a high degree of skill is required of the driver controlling such an automobile. Where an all-speed centrifugal governor is used instead, the foregoing inconveniences and drawbacks may be avoided but, since lever reaction force in all-speed centrifugal governors is large, this type of governor is not suitable for automotive engines. Fluid governors, on the other hand, are free from the above-mew tioned drawbacks characterizing the centrifugal governors, but their construction is so much complicated that they are necessarily expensive governors. Itfollows that any of these conventional types of governor does not fully meet the requirements for the automotive governor of the kind mentioned above.

The object of this invention is to provide a novel governor capable of the excellent control performance likethat of the fluid governor and yet constructed as simple as the centrifugal governor.

The invention will be hereinafter made clear by description with reference to the accompanying drawings, in which:

FIG. 1 shows in a cross section a governor constructed according to the invention;

FIG. 2 shows in a perspective view a guide lever portion of said governor;

FIG. 3 is a graph showing a discharge performance curve of a hydraulic pump employed in said governor;

FIG. 4 is a discharge pressure graph for said pump;

FIG. 5 is a graph showing the characteristic curves representing effects of control action of a control valve employed in said governor;

FIG. 6 is a graph showing governor performance curves;

FIG. 7 is a graph showing the characteristics of output torque for a diesel engine equipped with the governor of the invention; and

. FIG. 8 is a graph comparing the speed characteristics of output torque for a conventional diesel engine and a conventional gasoline engine.

Referring to FIGS. 1 and 2, an embodiment of this invention will be described in construction and operation. A flyweight holder 3 rigidly mounted on a camshaft 2 of a fuel-injection pump 1, carries flyweights 5, which are pivotally mounted thereon by means of pivot pins 4. The cylinder 3a, forming an extension of the flyweight holder 3 on the side opposite to the camshaft 2 is connected by oldham coupling 6 to the drive shaft 8 of a hydraulic pump 7 such as a trochoid pump. The pump 7 is built in the lower part of a governor case and serves as source of hydraulic pressure. The drive shaft 8 extends out in the direction opposite to Oldham coupling 6 through the governor case 15; its end portion, outside the case 15, is threadedly fitted with a bolt 39 having a square recess in its head. The bolt 39 holds a circular plate 38 fitted onto the drive shaft 8 this plate 38 is located to the drive shaft 8 by means of its slot 38a, into which is engaged a pawl 8a formed of the end portion of the shaftA lock washer 40, whose tongues are engaged with the slot 38a on the one hand and bear against the bolt 39 on the other, is fastened down by the bolt 39, so that this bolt is made unable to turn relative to the drive shaft 8. Furthermore, circular plate 38 is retained on the shaft 8 in such a position as will provide a small running clearance between its inside face and the outer surface of the governor case 15. The trochoid pump 7 lifts oil within the governor, and delivers pressurized oil from a discharge opening 9, provided in the lower part of the governor case 15, to an oil-pressure nor case 15 into which it is force fitted. A movable cylinder 11: is urged toward the right, as viewed in FIG. 1, by a power-;-

spring 16, whose one end is seated on the governor case and the other end on a flange 11a formed of the open-end portion of the cylinder 11. A fuel adjusting rod 14, which form a part of fuel injection pump 1 and is positioned parallel to the movable cylinder 11, is connected with flange 1 1a. The distal end of a stopper lever 18a, integral with a stop lever 18, can bear against the face of the flange 11a opposite to the other fac supporting a power spring 16. The stop lever 18 is rotatably'i mounted on a stopper lever shaft 17 held rigidly by the governor case 15, and is so adapted that, by an operating handle 20 at the control station to turn the stop lever 18 in the direction of the arrow, the fuel-adjusting rod 14 can be pulled in the direction decreasing fuel-injection quantity. The limit of the angular travel of the stop lever 18 returning (in the direction opposite to the arrow) is determined by the position of an adjustable stopper 19 secured to the governor case, to limit the maximum fuel-injection quantity. The closed end of the cylinder 11 comes into contact with a pushrod 22 extending from a bush 23 and backed by a damper spring 21 contained in said bush 23, when the fuel-adjusting rod (14) is pulled back all the way in the direction decreasing fuel-injection quantity. The bush 23, in which the damper spring 21 is compressed between the pushrod 21 and the closed end, is positioned coaxially to said cylinder 11 and threadedly held in the part 15a of governor case. The bush 23 can be screwed in or out to repose it axially for adjustment by turning it with a screwdriver put to the slot cut in its outer end face, where a locknut 24, run from outside onto the portion of the bush 23 protruding from the boss part 15a, secures the bush 23 in its set position. The oil-pressure supply opening 10 communicates to

ports

25a and 25b provided in sleeve 25, which is force fitted into and rigidly held in a hole drilled out in the boss part 15b of the governor case. This communication is through the oil hole 10a and its extension. A control valve 26, having two

piston portions

26a and 26b and annular recess 26d, is fitted with an oil-tight sliding clearance into the bore of a sleeve 25. Oil pressure, applying through said oil hole 10a, acts upon the face 26c of the control valve 26 through said port 25b. The other end face of the valve 26 is acted on by a control spring 27, which urges the valve 26 toward the right, in FIG. 1, by seating on the closed end of a spring holder 28. This holder 28, slidably fitted onto and surrounding the protruding portion of the sleeve 25, is capable of axial movement. During operation, as the valve 26 is made to slide to and fro in the bore of the sleeve 25, its piston portion 26a covers and uncovers a port 25a, thereby controlling the extent of opening A at this port. The sleeve 25 is provided with an another port 250, located diametrally opposite to said port 25a. The outer end face of a holder 28, which is urged by a spring 27 toward the left side bears against a cam 31. This cam is integral with a governor lever 30, which is interconnected by linkage to the accelerator pedal at the control station. The lift of the cam 31 changes with the angular position of the governor lever 30 pivoting on a shaft 29 held rigidly by the governor case. The open end of the holder 28 is formed with a flange 28a.

Next, attention will be redirected to the flyweights 5. Bellcranks 5a, by their tips, bear against the face of the right side end, in FIG. 1, of a sleeve 32 fltted slidably and rotatably onto the cylindrical portion 3a of the flyweight holder 3. The leftside end of said sleeve 32 bears against the lower tip of a guide lever 34 pivoted on a shaft 33. The shaft 33 is rigidly held by the governor case. The upper tip of the lever 34 is located at a certain distance from the above-mentioned flange 28a of the spring holder 28. As shown in FIG. 2, a torsion spring 35 is provided around the guide lever shaft 33 in such a way as to present a force opposing to the thrust sleeve 32 exerted when the centrifugal force of the flyweights 5 acts on this sleeve. The torsional preload or set load given to the spring 35 can be varied for adjustment by turning a adjusting bolt 37, held by the governor case: turning the bolt 37 changes the angular position of a stopper 36 secured to the distal portion of the shaft 33 to rotate this shaft. Obviously torsional spring 35 contemplated in the present embodiment may be supplanted by an ordinary coil spring. It will be readily understood that a coil spring hitched by its one end to the upper end of the guide lever 34 and by its other end to a lever radially studded in, and at a proper point of the lever shaft 33 provides the same effect as that of the torsional spring.

The operation of the governor constructed as above according to the invention will be explained by considering engine load variation, taking up first a reduction in engine load occurring during operation. A load reduction raises engine speed and, therefore, increases the rate of discharge flow from trochoid pump 7, raising, at the same time, the discharge pressure. This relationship is represented by the graph of FIG. 3, wherein the discharge flow rate Q" is taken on the coordinate and the rotating speed N of the pump drive shaft on the abscissa, and also by the graph of FIG. 4, wherein the discharge pressure, that is, pressure P" in chamber 13 is taken on the coordinate and the rotating speed N" on the abscissa. These graphs tell that the discharge rate is proportional primarily to rotating speed and secondarily to discharge pressure P. It will be seen that the pressure P varies as the area of opening through which the oil is discharged, that is, opening "A" at the port 2511 is varied. A rise in pressure P breaks the balance existing between oil pressure of the chamber 13 and power spring 16 and causes this cylinder 11, to slide toward the left, FIG. 1, to pull the fuel-adjusting rod 14 in the direction decreasing fuel-injection quantity until a new balanced state is reached. As a result of this reduction of fuel-injection quantity, the engine speed starts falling and decreases until the engine output balances with the reduced engine load. After the balance is reestablished between load and output, the engine runs in a steady-state condition. For an increase in engine load, on the other hand, the foregoing sequence of events takes place but in reverse order.

To be considered next is what happens when the governor lever 30 is manually turned in the direction of the arrow to, for example, the position indicated by the dot lines, FIG. 1. As the lever 30 is so turned, the cam 31 too turns, decreasing its lift and allowing the spring holder 28 to slide toward the left under the force exerted by the control spring 27. Consequently, the spring 27 stretches and its compressive force decreases, so that the hydraulic pressure acting on the face 250 of the control valve 26 overcomes the counteracting spring force and causes the valve 26 to slide toward the left to the position indicated the dot lines, thereby opening the

ports

25a and 25c and bleeding the oil in the chamber 13 out through the port 25a, the annular recess 26d and the port 250. This bleeding out of oil from the chamber I3 lowers the pressure therein to allow the cylinder 11 to be pushed toward the right by the spring I6, thereby pushing the adjusting rod 14 to increase the injection quantity and hence the engine output. If it is desired to reduce the engine output, the governor lever 30 must be turned in the direction opposite to the arrow and brought to, for example, the idling position represented by the lever 30 shown in solid lines in FIG. 1. The foregoing changes take place in accordance with the governor characteristic represented graphically in FIG. 6, wherein the rotating speed "N is taken on the coordinate and the position R of adjusting rod 14 on the abscissa, with the angular position 4: of the governor lever 30 taken as the parameter. Curves 41,, Q31. (provided qb, stand for the ascending order of angular positions. For fuel injection quantities below the point R., the damper spring 21 is effective, so that each curve with a numerical subscript rises more sharply for that injection range, as traced from right to left. The rising curves in dot lines are what would obtain if the damper spring 21 were absent. This spring serves to facilitate the restoring action of the adjusting rod 14 upon a rapid drop of engine speed and also to act like the idling spring in conventional governors.

As the engine speed rises in the range of higher speeds, the thrust exerted by sleeve 32 due to the centrifugal force of the flyweights 5 overcomes the torsional spring 35 to turn the guide lever 34 in clockwise direction, bringing this lever into contact with the flange 28a of the spring holder 28 and pushing the holder 28 toward the right, FIG. 1, to compress the spring 27 and thus push the control valve 26 to close the port 25a by its piston portion 26a. As was previously explained, closure of the port 2511 raises the pressure P to pull the fueladjusting rod 14 in the direction decreasing fuel injection quantity, thereby lowering the engine speed, until a steadystate condition is reached again. This high-speed control action is represented by curve in FIG. 6.

The object of the mechanism including the control valve 26, the spring 27, the sleeve 25 and the spring holder 28 is to provide a wider speed regulation for the control range covering idling speed and intermediate speeds of the engine in order to make the output characteristic approximate to that of the gasoline engine, so that the engine will not hunt during idling condition and, during intermediate-speed operation, the driver will get the same feel" as he would get when driving a vehicle with a gasoline engine. This connection is illustrated in FIG. 5, wherein the speed N" is taken on the coordinate and the adjusting rod position R on the abscissa, with the area of opening A at the port 25a taken as a parameter. The governor lever angle is taken also as a parameter. When the opening A of the port 25a is constant, position "R" varies more widely for a change in speed N, as indicated by dot-line curves, but when the opening A" varies as a function of speed N, with the governor lever 30 held in a constant position, position R" changes not so widely, as indicated by solidline curves. A running engine can be stopped by turning the handle 20 to turn the stop lever 18 in the direction of the arrow, thereby pulling the fuel-adjusting rod in the direction decreasing fuel-injection quantity, irrespective of the governor action. The maximum injection quantity position of the fuel-adjusting rod corresponds to the position of the stopper 18a turned all the way counterclockwise to bear against the stopper bolt 19, with its tip touching the flange 11a of the cylinder 11. This position of the stopper 18a can be varied by means of the stopper bolt 19. Thus, it is possible to obtain a fuel setting best suited to each engine. In the Bosch-type fuel injection pump whose beginning of injection occurs at the moment the head of a rising plunger has just covered the inlet port provided in the barrel, it is necessary to match the camshaft 2 to the engine crankshaft in phase relationship, so that the beginning of injection" of the pump will be in step with the prescribed beginning of injection in the engine. This matching can be effected by referring to the timing marks provided on the plate 38 and on the governor case 15. Where a tachometer or a service meter is employed, its drive shaft may be coupled to the drive shaft 8 by inserting the end of the former into a square recess 39 provided in the outer end of the shaft 8.

The foregoing description may be summarized, as follows, to enumerate the novel features of the governor according to the invention:

1. While, in conventional centrifugal governors, a change in the rotating speed due to a change in engine load varies the controlling force arising from centrifugal force, the governor according to the invention compensates the hydraulic pressure by means of the control valve for a change in speed, so that an adequate controlling force is secured for the engine in low-speed running condition.

2. The invention provides an all-speed governor in which lever reaction force is small.

3. FIG. 7, wherein the output torque T is taken on the coordinate and the engine speed N" on the abscissa, with the accelerator pedal positions (11,, (b (d taken as a parameter, refers to a diesel engine equipped with a governor according to the invention. FIG. 8, wherein the coordinate and the abscissa represent torque T" and speed N" as in FIG. 7, has the parameter, namely, accelerator pedal position indicated by curves D D (D D for a diesel engine equipped with a conventional maximum-speed minimum speed governor by curves d (1,. (d, d for a diesel engine equipped with an all-speed governor, and by curves 6,, G (G, G for a gasoline engine. it will be noted that the curves 4) of FIG. 7 are similar to those of the gasoline engine in FIG. 8. The similarity signifies that, as compared with conventional maximum-speed minimum-speed governors, the governor according to this invention provides as high a rate of acceleration for a given stroke of the accelerator pedal as that of gasoline-engine vehicles, thereby improving the feel of acceleration the driver senses in accelerating the engine, and, for changes in load of the kind mentioned above, makes it unnecessary for the driver to possess a high degree of driving skill. The above novel features are made possible in a relatively simple governor construction to add to the practical value of the governor according to the invention.

What is claimed is:

1. A governor for an internal combustion engine of the injection type comprising: an oil supply means for supplying oil under a pressure which varies with the rotational speed of the engine; a pressure actuated cylinder means for reciprocating a fuel-adjusting rod of the injection pump in response to pressure of oil supplied by said oil supply means; a first spring means operating on said cylinder means in opposition to the force exerted on the cylinder means by the pressure of said oil from the oil supply means; control valve means communicating with the pressure oil in the cylinder means and including means for controlling the extent of opening of a bleed hole to bleed oil out of said cylinder means, said control valve having a valve piston with an annular recess formed thereon, means for connecting the oil from the cylinder means to the valve piston to increase the opening of said bleeding hole by oil pressure from the cylinder means, and a second spring means operating on said valve piston for decreasing the said bleed opening, whereby a given operating condition of the control valve means is established by the balance of both forces to define the extent of opening of the bleeding hole; lever means for rotating manually a cam for regulating the spring load of said second spring means of the control valve for controlling manually said control valve means; and a centrifugal governor means for operating, in the closing direction, the opening of the bleeding hole of said control valve means to an extent which varies with the rotational speed of the engine, a lever arm, said centrifugal governor means including flyweights rotating in response to rotational speed of the engine and operable to urge the lever arm to move the control valve means in a direction to close the bleeding hole, and a third spring means operating on the lever arm in opposition to the force of the flyweights such that when the flyweights exceed a fixed rotational speed, rotating by centrifugal force, the lever arm is acted on by the force of the said third spring means against the centrifugal force of the flyweights.

2. A govemor according to claim 1, wherein the governor is housed in a casing attached to the fuel-injection pump and the oil supply means and the centrifugal governor means are arranged coaxially with a cam shaft of the injection pump.

3. A governor according to claim 1, said oil supply means being a hydraulic pump rotating coaxially with the camshaft of the fuel-injection pump and varying the feed pressure of the oil in response to the rotational speed of the camshaft; said cylinder means being a chamber hydraulically connected with said hydraulic pump; an end cylinder closing one end of said chamber and being movable in response to oil pressure in said chamber, said cylinder being connected to said fuel-argusting rod, the axes 0 being the cylinder and the fuel-adjusting ro substantially parallel to each other, said cylinder arranged to receive both the force of the first spring means and the opposing force of the oil pressure in the chamber, whereby the cylinder is located axially, together with the fuel-adjusting rod, by the balance of the forces of the oil pressure and the said first spring.

4. A governor according to claim 3, said control valve means being connected with said chamber through an oil hole, said control valve means including a sleeve with ports communicating to the oil hole, and said valve piston located within the sleeve and axially receiving the spring force of the second spring which is located in the sleeve, said valve piston receiving oil pressure of the said chamber through one of said ports, and in response to which pressure it moves to increase the opening of one of the other ports, said second spring acting in opposition to said oil pressure force to decrease the opening of said ports, the final extent of the opening of said ports being determined by the balance of both the pressure oil force and the force of the second spring to control bleeding from said chamber.

5. A governor according to claim 4, wherein only when the rotational speed of the flyweights exceeds a fixed value does said centrifugal force overcome the opposite force of said third spring means to operate said lever arm to operate said control valve means to decrease the opening of said bleeding port.

Claims

1. A governor for an internal combustion engine of the injection type comprising: an oil supply means for supplying oil under a pressure which varies with the rotational speed of the engine; a pressure actuated cylinder means for reciprocating a fueladjusting rod of the injection pump in response to pressure of oil supplied by said oil supply means; a first spring means operating on said cylinder means in opposition to the force exerted on the cylinder means by the pressure of said oil from the oil supply means; control valve means communicating with the pressure oil in the cylinder means and including means for controlling the extent of opening of a bleed hole to bleed oil out of said cylinder means, said control valve having a valve piston with an annular recess formed thereon, means for connecting the oil from the cylinder means to the valve piston to increase the opening of said bleeding hole by oil pressure from the cylinder means, and a second spring means operating on said valve piston for decreasing the said bleed opening, whereby a given operating condition of the control valve means is established by the balance of both forces to define the extent of opening of the bleeding hole; lever means for rotating manually a cam for regulating the spring load of said second spring means of the control valve for controlling manually said control valve means; and a centrifugal governor means for operating, in the closing direction, the opening of the bleeding hole of said control valve means to an extent which varies with the rotational speed of the engine, a lever arm, said centrifugal governor means including flyweights rotating in response to rotational speed of the engine and operable to urge the lever arm to move the control valve means in a direction to close the bleeding hole, and a third spring means operating on the lever arm in opposition to the force of the flyweights such that when the flyweights exceed a fixed rotational speed, rotating by centrifugal force, the lever arm is acted on by the force of the said third spring means against the centrifugal force of the flyweights.

2. A governor according to claim 1, wherein the governor is housed in a casing attached to the fuel-injection pump and the oil supply means and the centrifugal governor means are arranged coaxially with a cam shaft of the injection pump.

3. A governor according to claim 1, said oil supply means being a hydraulic pump rotating coaxially with the camshaft of the fuel-injection pump and varying the feed pressure of the oil in response to the rotational speed of the camshaft; said cylinder means being a chamber hydraulically connected with said hydraulic pump; an end cylinder closing one end of said chamber and being movable in response to oil pressure in said chamber, said cylinder being connected to said fuel-adjusting rod, the axes of the cylinder and the fuel-adjusting rod being substantially parallel to each other, said cylinder arRanged to receive both the force of the first spring means and the opposing force of the oil pressure in the chamber, whereby the cylinder is located axially, together with the fuel-adjusting rod, by the balance of the forces of the oil pressure and the said first spring.