US2493883A - Speed governor - Google Patents

Description

T. l. LARSEN SPEED GOVERNOR Jan. l0, 1950 Filed May 26, 1945 DJM @0% M53@ Patented Jan. 10, 1950 SPEED GOVERNOR Torleif Ingolf Larsen, Farmington, Mich., assgnor to King-Seeley Corporation, Ann Arbor, Mich., a corporation of Michigan Application May 26,1945, Serial No. 595,990

4 Claims.

This invention relates to speed governors for internal combustion engines, and more particularly to governors of the velocity or mixtureflow type. Such governors consist essentially of a valve or throttle-plate mounted on a rotatable shaft extending transversely of the intake manifold of the engine to be governed, said shaft being off the center line of the manifold passage, whereby the forces exerted on the throttle-plate by the passage of fuel mixture through the manifold tend to move the plate from open towards closed position, said forces having varying values as the plate changes position. A reactance device in the form of a spring or combination of springs connected to the throttle-plate spindle or shaft through a suitable linkage, is employed to produce a balanced condition of the plate, in all positions, at governed speed, the positions of the throttle-plate, and, hence, the amount of fuel mixture passing to the engine, being dependent upon the load imposed upon the engine.

In all velocity type governors, there is a certain variation between full-load speed and no-load speed, which variation must be permitted in order to secure proper functioning of the governor, as is well understood in the art. This increase in no-load speed as compared with full-load speed is preferably less than 10% of the governed speed, and is known as the regulation of the governor. Theoretically, the rate of increase in governed speed between full-load and no-load conditions is uniform, and, if plotted in terms of R. P. M. versus brake-horsepower, would give a straight-line loading curve or load-speed curve. However, in practice, this desirable result has been achievedonly in part.

In a velocity type governor, the forces acting upon the throttle-plate, due to the passage of fuel mixture through the intake conduit have been considered as two-fold, namely, impingement of the fuel mixture upon the differential exposed areas of the throttle-plate, and the difference in uid pressure upstream and downstream of the throttle-plate. As is well known, the pressure upstream of the throttle-plate is substantially atmospheric when the carburetor throttle-valve is in open position, as is the case when the engine is being operated under control of the governor. The degree of vacuum below or downstream of the governor valve, at governed speed, changes with the load, varying from a towards closed position change but very little with an increase in speed, and for this reason the loading curve or loading characteristic of such governors has, in the past, departed considerably from the desired straight line cuve under conditions of light load or no load, resulting in a considerable increase of speed under such lightload or no-load conditions. This undesirable increase in speed has heretofore been tolerated as essential to produce the necessary force to close the valve.

The general object of the present invention is the provision of an improved speed governor o f the velocity or mixture-flow type, in which the force necessary for proper governor Valve closure under no-load conditions is produced without resorting to engine speed increase, whereby a better loading characteristic or load-speed curve is obtained.

A further object is the provision of a governor of the type described in which, when the governor valve approaches closed position due to reduction in load, a force in addition to those normally acting upon the governor Valve is employed for urging the latter toward closed position.

Another object is the provision of a governor of the type described in which special means, subject to the engine vacuum below the governor Valve are employed to increase the forces acting to move the valve toward closed position.

Another object is the provision of an improved governor according to the last-stated object, in which the special means are actuated only when the engine vacuum exceeds a predetermined value.

Other and further objects, features and advantages will be noted from the description which follows, taken in connection with the accompanying drawings, in which Fig. 1 is a sectional view of a governor constructed in accordance with the present invention, on a plane including the axis of the fuelmixture passage and normal to the throttle-valve shaft;

Fig. 2 is an elevation of a governor according to Fig. 1, with spring-box cover removed;

Fig. 3 is a graph showing throttle-plate torque curves of a conventional governor and a governor according to the present invention; and

Fig. 4 is a graph showing the loading curves of a conventional governor and a governor according to the invention.

In order to facilitate an understanding of the invention, reference is made to the embcdiments ing a fuel-mixture conduit l l. body is intended to be inserted in the intake manifold between the carburetor and the engine, and

` throttle thereof shown in accompanying drawings, and detailed descriptive language is employed. It will, nevertheless, be understood that no limitation of the invention is thereby intended and that various changes and alterations are contemplated such as would ordinarily occur to one skilled in the art to which the invention relates.

Referring now to Fig. 4, the portion of the curve between the intersection of the coordinates and the point A represents the speed-torque curve of a velocity governed internal combustion engine, while the straight line ACD denotes a theoretically correct loading curve in which there is a slight, constant increase of speed with reduction in load. In practice, the actual loading curve ACB follows the line ACD as far as the point C, which corresponds roughly to an engine vacuum,

below the governor valve, of 17" of Hg. From this point onward, the the load is reduced, and due to the previously mentioned fact that the forces exerted upon the unbalanced governor valve by the mixture-flow change but little with increasing speed in the higher vacuum ranges, the loading curve ACB departs at an increasing rate from the line ACD, the actual departure at no-load varying from 209B. P. M., inthe case of well-designed governors, to very much larger values in less carefully-designed governors.

By the provision of special means in accordance with the present invention, it is possible substantially to eliminate this undesirable tailing H, and to approach closely the performance illustrated by the line ACD in Fig. 4.

1n Fig. 3 the curve E illustrates the torque exerted upon the throttle-plate of a conventional velocity type governor, plotted against degreesv of throttle opening. t will be noted that the rate of increase constantly ascends approximately to the position line, after which the rate falls off and the curve breaks.

the object of the present invention, means are employed for preventing this break in the torque curve or, in other words,v for causing the rate of from the fully open position. Such a performance is illustrated by curve G in Fig. 3.

Referring now to Fig. l, the embodiment there illustrated comprises a governor body l enclos- The governor with the conduit l l aligned with said manifold passage, the direction of flow of fuel mixture being indicated by the arrows in Fig. 1. The governor valve consists of a throttle-plate I2 secured upon a shaft i3 extending transversely through the fuel conduit. It will be noted that the shaft I3 is mounted eccentrically with respect to the fuel conduit, and the throttle-plate I2 is 1 mounted eccentrically with respect to the shaft i3, whereby the upstream Yportieri ofthe throttlelplate. is-considerably larger in area than the downstreamvportion. The shaft i3 is connected to a spring-balancing mechanism i4 and linkage,

which .linkage and spring-balancing mechanism are conventional and well understood in the art.

The,spring-balance'mechanism is so designedY `as theoretically to balance the forces acting to close the throttle-plate at governed speed, in all positions, the expression governed speed being understood to include the degree of regulation involved, as pointed out above.

The novelfeatures of the present inventionV In order to accomplish reside in the mechanism shown at the right-hand side of Fig. l and comprising a piston-like valvemember i5 slidably mounted in a cylinder i6 provided with a suitable bore in the governor body Iii. The cylinder i 6 is ported to the fuel-mixture conduit Il at il and i8, which are respectively.

upstream and downstream of the upstream edge of the throttle-plate l2 when the latter is in partly closed position, as shown in dotted lines. The valve-member i5 is provided at either end with enlarged portions or heads i9, 20, having a fairly close nt within'the cylinder H5, the valve-member being normally urged to its upward position by a spring 2 i The cylinder is also 1 ported to the fuel-mixture conduit at points beyond either end of the valve-member l5, as at 22, 23, respectively. Thus, the upper end of the valve-member l5 is subject to the fluid pressure on the upstream side of the throttle-plate, while the lower end of the valve-member is subject to the fluid pressure downstream of the throttleplate.

When the throttle-plate i2 is in a wide-open or substantially open position, as at heavy and medium loads, the pressures above and below the throttle-plate are substantially equal, and no 'significant fluid pressure, therefore, is exerted As the load upon the engine decreases, and

the throttle-plate accordingly moves to a nearly closed positionfor example, the 50 position, as

shown in Fig. S--the fluid pressures above and below the throttle-plate become unequal, the pressure above the plate being substantially atmospheric, and the pressure below the plate corresponding substantially to the engine vacuum,

"f except as these pressures are partially equalized by virtue of the by-passing of a portion of the fuel mixture, as explained above. Under these conditions, the engine vacuum is partially exerted upon the lower face of the valve-member l5, causing the latter to move downwardly against the pressure of the spring 2 i, thus partially closing the port il. lThe partial closure of the port il, of course, increases the difference of pressures above and below the throttle-plate, thus increasing the closing forces acting upon the throttle-plate l2. Under some conditions, and at extreme light loadsor no load,.it may result that theV port I7 will be entirely closed by the valve-member if going to its extreme lower position in order to effect a sucient closure of the throttle-plate to maintain governed speed.

From the foregoing it will be understood that an additive force is applied in a closing direcsubstantially tc the Vtheoretically perfect curve ACD.-

From the foregoing description it will be apparent .that the present invention provides means for accomplishing the objects hereinabove stated.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is:

1. In a speed governor for internal combustion engines, a governor body enclosing a fuelmixture conduitL an unbalanced throttle-plate supported in said conduit and arranged to be moved toward closed position by the flow of fuel mixture therethrough, resilient means for resisting said movement in the closing direction, and means for supplementing the closing forces acting on said throttle-plate when in semi-closed position, said last means comprising an auxiliary fuel-mixture passage by-passing that portion of said fuel conduit responsive to the pressure differential across said throttle plate but occupied by the upstream edge of the throttle-plate when in semi-closed position, a valve for controlling or stopping the flow of fuel mixture through said passage, means urging said valve towards open position, and means acting independently of the pressure within said passage for moving said valve toward closed position as said throttle-plate approaches closed position.

2. In a speed governor for internal combustion engines, a governor body enclosing a fuel-mixture conduit, an unbalanced throttle-plate supported in said conduit and arranged to be moved toward closed position by the flow of fuel mixture therethrough, resilient means for resisting said movement in the closing direction, and means for supplementing the closing forces acting on said throttle-plate when in semi-closed position, said last means comprising an auxiliary fuelvmixture passage by-passing that portion of said fuel conduit responsive to the pressure differential across said throttle plate but occupied by the upstream edge of the throttle-plate when in semi-closed position, a valve for controlling or stopping the flow of fuel mixture through said passage, means urging said valve towards open position, and means under the control of vacuum downstream of said throttle-plate but independent of the pressure within said passage for moving said valve toward closed position as said throttle-plate approaches closed position.

3. In a speed governor for internal combustion engines, a governor body enclosing a fuelmixture conduit, an unbalanced throttle-plate supported in said conduit and arranged to be moved toward closed position by the now of fuel mixture therethrough; resilient means for resisting said movement in the closing direction, and means for supplementing the closing forces acting on said throttle-plate when in semi-closed position, said last means comprising an auxiliary fuel-mixture passage parallel to said conduit and having ports communicating therewith at points upstream and downstream, respectively, of the upstream' edge of said throttle-plate when the latter is in semi-closed position, a valve-member movable in said passage to control or stop the flow of fuel mixture through said passage, resilient means urging said valve-member toward open position, and means responsive to the pressure differential across said throttle plate but acting independently of the pressure within said passage for moving said valve-member toward closed lposition as said throttle-plate approaches closed position.

4. In a speed governor for internal combustion engines, a governor body enclosing a fuelmixture conduit, an unbalanced throttle-plate supported in said conduit and arranged to be m'oved toward closed position by the ow of fuel mixture therethrough, resilient means for resisting said movement in the closing direction, and means for supplementing the closing forces acting on said throttle-plate when in semi-closed position, said last means comprising a passage parallel to said conduit and having ports communicating therewith, at points upstream and downstream, respectively, of the upstream edge of said throttle-plate when the latter is in semiclosed position, a valve-member movable in said passage and adapted to control the flow of fuel mixture through said passage, and resilient means urging said valve-member toward open position; said valve-member having heads at either end thereof, said heads closely fitting said passage, and said passage being ported to said conduit at points beyond said respective heads.

TORLEIF INGOLF LARSEN.

REFERENCES CITED UNITED STATES PATENTS Name Date Mallory June 29, 1943 Number

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