US2115125A - Control means for internal combustion engines - Google Patents

Description

April 26,1938. H. SIINCLAIR 2,115,125

CONTROL MEANS FOR INTERNAL COMBUSTION ENGINES Filed Nov. 17, 1936 r so ao iver- 72 Patented Apr. 26, 1938 UNITED STATES ATENT OFFICE CONTROL MEANS FOR INTERNAL COMBUS- TION ENGINES Harold Sinclair, Kensington, London, England Application November 17, 1936, Serial No. 111,202 In Great Britain November 21', 1935 11 Claims. (c1. 192-.o1)

torque transmitted by the coupling owing to the a higher speed of the impeller member thereof being suflicient to set the vehicle in motion. The vehicle may thereafter be stopped by merely shutting the engine throttle or equivalent contro and applying the vehicle brakes. s

When such a motor vehicle is manoeuvred in this. way, the difliculty arises that, when the throttle is suddenly shut while the vehicle is moving very slowly or is stationary, the drag imposed on the engine by the hydraulic coupling is apt to stall the engine. This difiiculty appears to arise from the fact that a sudden return of the throttle control from an open position to the idling posi- 'tion momentarily upsets the mixture. strength, and owing to the resistance of the coupling the engine rapidly slows down to the stalling point before there is time for stable idling conditions to be established. This, tendency to stall can be avoided in practice by arranging for the idling speed of the engine to be rather higher than is usual on vehicles not provided with a hydraulic coupling.

This increased idling speed, with the correspondingly increased drag torque of the coupling, is a disadvantage of such transmission systems, and alternatives are to provide the engine with a heavy flywheel or to arrange for the torque transmission capacity of the coupling to be abnormally low when the impeller, is rotating slowly. Both these expedients have obvious objections, namely, the heavy flywheel impedes the acceleration of the engine, and in the other alternative the low torque transmission capacity or high slip of the coupling leads to a reduction in the efliciency of power transmission.

' The object of the present invention is to overcome or reduce all the disadvantages referred to.

According to the present invention, a power plant comprising an internal-combustion engine and a hydraulic power transmitter of the kinetic type is provided with means which are adapted automatically to delay the final part of the movement into its idling position of the power con- 1 trol member of the, engine, while having no substantial eifect on this member over the remainder of its range of movement.

Thus, where the engine is of the carburetter type, the power control member being the throttle-actuating member of the carburetter, the said means are adapted automatically to delay the movement of the throttle-actuating member from a slightly-open position to the idling position.

Where, as on a motor vehicle, the engine throttle is controlled by an accelerator pedal, this pedal may be coupled to the engine throttle by an operative linkage including a lost-motion connection, there being provided a return'spring acting on the part of this linkage between the lostmotion connection and the throttle and an independent return stop for the accelerator pedal,

and the means for delaying movement of the throttle co-operating with this part of the linkage. In this way the delaying means may in consequence be relatively small and light.

Alternatively, the delaying means may be ar- 26 ranged to act directly on the accelerator pedal,

or on any convenient connecting member between this pedal and the throttle, so as to delay the final movement of the throttle into its idling position, but with this arrangement the delaying 30 means must be powerful enough to deal with the inertia effects and strength of spring of the accelerator pedal as well.

The delaying means preferably have the form of a hydraulic dash-pot, which may include "a butffer which is displaced by the actuating mech- I anism of the power control member of the engine only when this mechanism is moving through the final part of its .range into the idling position. The hydraulic dash-pot may be. provided with a check-valve arranged to permit a rapid movement in the direction in which it moves when the engine is accelerated from idling speed, so that the device will operate efiectively even when the engine is'accelerated and retarded in rapid succession.-

The delay necessary to obviate stalling o! the engine is-usually between A and second, and

is thus not so long as to interfere with the nicety of control when manoeuvring.

An example of the present invention as applied to an automobile will be described with reference to the accompanying drawing in which:-

Fig. 1 is a part-sectional diagrammatic side retter elevation of part of the power transmission mechanism,

Fig. 2 is a part-sectional side elevation of the delaying means shown in Fig. 1, and

. Fig. 3 is an enlarged detail of a part of Fig. 2.

The power plant shown in Fig. 1 includes an internal-combustion engine ||l having a carbu- The power output of the engine is controlled by a throttle having an actuating memher in the form of a lever l2, which is urged towards the idling position, in which it is shown, by a return spring l3. The idling position of the throttle actuating lever I2 is adjustable by a screw 50 which bears against a stop 5| on the body of the carburetter and which is engaged in a screw-threaded hole in the lever I2. The-engine crank-shaft I4 is fixed to the impeller l5 of a hydraulic. coupling IQ of the kinetic type, the

runner ll of which is fixed to the input shaft I8 of change-speed gearing I9. The driven shaft 20 of this gearing is drivably connected by means not shown to the driving wheels ofthe vehicle.

An accelerator pedal 2|, hinged to a fixed support 22, is coupled by a pivoted link 23 to a lever 24 which is fixed to a shaft 25. This shaft is journalled in rigid brackets such as 26, and to it is keyed a two-armed lever 21. In the upper arm of this lever is fixed an adjustable stop-bolt 28, which co-operates with an abutment 26' formed on the bracket 26. A pedal-return tension spring 23 may be connected between the lever 21 and any suitable fixed point.

The lower arm of the lever 21 is pivoted to a link 30 which in turn is pivotally connected to an arm 3| of a bell-crank lever 3|, 32 by a lostmotion connection formed'by an elongated eye 30"in the link 30 and a pin 3| fixed in the arm 3| and slidably fitted in the eye 30. The arm 32 of the bell-crankis coupled to the throttle lever |2 by a pivoted link 33.

The bell-crank lever 3|, 32 forms part of a dash-pot device shown in larger scale in Fig. 2. The dash-pot device includes a base plate 34 fixed to the engine l0 and provided with a pivot pin 35 for the bell-crank lever 3|, 32. On the plate 34 is fixed a guide 36 having a cylindrical bore in which is slidably mounted a hollow cylinder 31 one end of which is sealed by a plug 33 which 'co-operates with a projection 3|A on the arm 3| of the bell-crank lever. To the other end of I the cylinder 31 is fixed, for example by a soldered nipple 48; one end of a corrugated cylindrical-metal bellows 39 the other end of which is fixed to a bolt 40 adjustably held in an eye 42 on the base 34. by nuts 4|. The interior of the bellows 33 is separated from the interior of the cylinder 31 by a check valve 43 screwed into the nipple 48 and provided with a spring-loaded ball 44 normally held on a seating 45 and obstructing a duct 46 leading to the interior of the buffer. In the seating 45 is cut a shallow radial channel 41 (Fig. 3). The interior of the bellows is completely filled with liquid, while the interior of the cylinder is about half filled, a suitable liquid being a thin mineral oil.

The apparatus works as follows. When the throttle is more than slightly open, the bell-crank lever 3|, 32 is in a direction anti-clockwise of its position shown in Fig.. 2. and, [since the bolt 40 is so adjusted that thecylinder 31 is not dis placed to the right of its position in Fig. 2, the

by the dash-pot left-hand end of the elongated eye 30' When,

however, the bell-crank lever reaches the position shown in Fig. 2, where the projection 3| A strikes the cylinder plug 38, movement of the cylinder 31 to the left is resisted by the action of the liquid in the bellows 39, which can escape to the interior of the cylinder only slowly through the channel 41 in the seating of the check-valve. The rapid closing of the throttle is consequently checked. Meanwhile the pedal return spring 23 has continued to raise the pedal until it is stopped by the stop bolt 28 striking the abutment 26'. The length of the elongated eye 30' is such that the pin 3| is now at the right-hand end of this eye, as shown in Fig. 2. As the liquid gradually ,leaks through the check-valve, the throttle is moved by the throttle return spring |3 relatively slowly from the slightly open position (in which the bell-crank lever is in the position of Fig. 2) to the closed position shown in Fig. 1.

If the accelerator pedal is rapidly depressed again, the bell-crank lever moves anti-clockwise and the cylinder is forced ,out to the position shown in Fig. 2 by the elasticity of the bellows 39, this return movement of the cylinder being relatively rapid owing to the free flow of liquid through the check valve from the cylinder to the bellows.

In place of a fluid dash-pot any equivalent damping device may be employed.

I claim:

1. A power plant comprising an internal-combustion engine having a power control member, a hydraulic power transmitter of the kinetic type drivably coupled to said engine, and means operatively associated with said power control member and serving automatically to delay the final part of the movement into its idling position of said member, while having no substantial effect on said member over the remainder of its range of movement. J

2. A power plant comprising an internalcombustion engine having a carburetter provided with a throttle, a hydraulic power transmitter of the kinetic type drivably coupled to said engine, and means operatively associated with said throttle and serving automatically to delay the movement of said throttle from a slightly-open position to the idling position, while having no substantial eifect on the throttle over the remainder of its range of movement.

3. A power plant comprising an internal-combustion engine of the throttle-controlled carburetter type, a hydraulic power transmitter of the ing automatically to delay'the closing movement of said throttle only from a slightly-open position to the idling position.

4. A power plant comprising an internal-comustion engine having a carburetter provided with a throttle, a hydraulic power transmitter of the kinetic ty-pe drivably connected with said engine, and a hydraulic dash-pot operatively associated with said throttle for delaying only the last part of the closing movement thereof into the idling position. i

5. A power plant comprising an internal-com bustion engine having a carburetter provided with a throttle, a hydraulic power transmitter of the kinetic type drivably connected with said engine, means for actuating said throttle, and a buffer comprising a slidable member which is so disposed in the path of said actuating means as to be displaced thereby only when said throttle is being moved through the last part of its range into the idling position, and means cooperating with said slidable member for retarding the movement thereof.

6. A power plant comprising an internal-combustion engine having a carburetter provided with a throttle, a hydraulic power transmitter of the kinetic type drivably connected with said engine, means for actuating said throttle, and a bufier having an abutment surface which is so disposed in the path of said actuating means as to be displaced thereby only when said throttle is being moved through -the last part of its range into the idling position, said bufier comprising means for elastically urging said abutment surface towards said throttle-actuating means, and for retarding movement of said abutment surface in the opposite direction.

7. Apparatus as claimed in claim 6, wherein said bufler includesa hydraulic dash-pot.

8. Apparatus as claimed in claim 6, wherein said bufier includes a hydraulic dash-pot comprising a check valve adapted to permit rapid an accelerator pedal, and an operative connection between said pedal and said throttle, characterized by the provision of a delay-action device co-operating with said connection and serving to delay the closing movement of said throttle only through the part of its range from a slightlyopen position into the idlingposition.

10. An internal-combustion engine comprising a power-control member having an actuating element, amember slidable along the path'of said actuating element and capable of contacting therewith only over the final part of its range of movement into the position corresponding to idling of said. engine, an elastic fluid-tight bellows connected between said slidable member and a fixed abutment, a reservoir chamber communicating with the interior of said bellows, and valve means permitting a relatively free flow of liquid from said reservoir to said bellows and a restricted flow of liquid from said bellows to said reservoir.

11. An automobile comprising an internalcombustion engine of the carburette'r type having a throttle, a hydraulic power transmitter of the kinetic type drivably connected with said engine, an accelerator pedal, an operative linkage, including a lost-motion connection, between said pedal and said throttle, a relatively ,strong return spring acting on the part of said linkage between said lost-motion connection and said throttle, an independent stop limiting the return movement of said pedal, a displaceable member co-operating with said part of said linkage and capable of contacting therewith over only the final part of its movement into the' position in which the engine idles, said displaceable member being associated with damping means serving to delay its movement into the position corresponding to idling of said engine, and to yieldingly urge said displaceable member in the opposite direction. 1

HAROLD, SINCLAIR.

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