US2703076A - Valve hydraulic control device for internal-combustion engines - Google Patents

Description

March 1, 1955 A CHAUDE 2,703,076

B. J. VALVE HYDRAULIC CONTROL DEVICE FOR INTERNAL-COMBUSTION ENGINES Filed Jan. 12, 1954 awn/ran; Bcvwnul Sun! ALBERT chnul BY 75% WMMW Arm/m5):

Uicd rates 2,703,076 Patented Mar. 1, 1955 VALVE HYDRAULEC CONTRQL DEVICE FOR INTERNAL-CGMEEUSTHDN ENGINES Bernard Jean Albert Chaud, Paris, France Application January 12, 1954, Serial No. 403,521 Claims priority, application France .lanuary 23, 1953 3 Claims. (Cl. 123-9l)) The present invention relates to valve hydraulic control devices for internal combustion engines, and especially four stroke engines.

The object of my invention is to provide a device of this kind which is better adapted to meet the requirements of practice than those known up to the present time.

According to my invention, the hydraulic valve con trol device, which includes in a known manner a reciprocating piston pump, is provided with means for causing the piston of said pump on one reciprocation thereof to operate the engine valve and on the next reciprocation to circulate oil or any other liquid used for the valve control in always the same direction through its circuit, whereby the control liquid in contact with the valve'control piston is constantly renewed.

' Other features of my invention will become apparent in the course of the following detailed description of embodiments thereof with reference to the accompanying drawings, given merely by way of example, and in which:

.Fig. l is a diagrammatic view partly in elevation, partly insection, of a four stroke internal combustion engine provided with a hydraulic valve control device according to my invention.

. Fig. 2 shows a modification of a detail of the device of Pi 1.

is it is known in the art, my hydraulic valve control device includes a reciprocating piston pump driven by the engine and connected through a suitable circuit with a power cylinder in which isprovided a piston intended to actuate the valve. to be controlled against the effect of a return spring, the liquid used in this circuit being supplied from a suitable reservoir.

The chief object of my invention is to provide a device of this kind where the operation of the hydraulic control means is automatically adjusted despite possible leakage of liquid or variations of volume of the elements of the hydraulic circuit.

For this purpose, according to my invention, i provide the hydraulic control device with means such that, periodically: during one reciprocation of the pump, including an inward stroke and a return stroke of the piston thereof, any communication of the elements of the system With the reservoir is cut off, whereby the hydraulic piston contained in the power cylinder is reciprocated to operate the valve; then, during the next inward stroke of the pump piston, the power cylinder outlet is placed in communication with the reservoir and during the next return stroke of the pump piston, the pump intake is placed in communication with said reservoir, the engine valve remaining applied upon its seat by a return spring during these two last'mentioned strokes.

, Thus, theliquid serving to the hydraulic control is constantly renewed in the power cylinder.

This renewal of the control liquid has the chief advantage of eliminating the need of any adjustment, either when assembling the parts or to compensate for wear and tear, since any leakage of the liquid or any variation of volume in the hydraulic circuit, especially as a result of variations of temperature, is automatically and immediately compensated for. Furthermore, the liquid which circulates during the renewal of the liquid improves the cooling of the valve and of its housing.

The pump must therefore have two reciprocations for every cycle of the engine. In the application to a fourstroke internal combustion engine (to which my device is particularly well adapted), the pump piston must therefore have one reciprocation for every revolution of the engine shaft. Therefore, the pump is actuated by a cam (or an eccentric or the like) rotating at the same speed as said shaft and preferably directly carried by it.

In order to improve the cooling action of the liquid on the engine valve, the piston which operates said valve is preferably constituted by the valve stem itself andthe return spring of said valve is housed in the power cylinder.

The hydraulic control device according to my invention may be applied either to exhaust valves, or to inlet valves or both to inlet and exhaust valves. It may be applied either to single cylinder engines, or to multicylinder engines, and in the last mentioned case, I make use of a single cam (or the like) and of a number of reciprocating piston pumps equal to the number of cylinders of the engine, the pistons of said pumps being disposed substantially in the same plane (that of said cam) and at suitable angles to each other.

in the embodiment illustrated by Fig. 1, reference numeral 1 represents the cylinder of a single cylinder engine or one of the cylinders of a multi-cylinder engine, 2 being its piston, 3 the exhaust valve, 4 the inlet valve, 5 the rankshaft and 6 the crank case.

T he control circuit of the exhaust is constituted by the following elements:

A reciprocating piston pump including a cylinder 7 in which is mounted a plunger 8 subjected to the action of a spring 9 and actuated by a cam 19 keyed on crankshaft 5;

A pipe iii;

A power cylinder 11 into which projects the end of the stem 12 of exhaust valve 3, the return spring 13 of said valve being also housed in said cylinder 11;

A return pipe 14;

A. feed pipe 15; and

A reservoir for the liquid contained in this circuit. This liquid consists preferably of the lubricating oil of the engine, which makes it possible to use as reservoir the crank-case 6 of said engine. Of course, pipe 15 starts from a point located below the normal level 16 of the oil in the crank-case. For practical purposes, pipe 10 and/ or pipe 14 may be made integral with the cylinder block and cylinder ll may be incorporated in the cylinder head. For the sake of clarity, the elements of the hydraulic control device and in particular pump 7 have been shown on a larger scale than the remainder of the engine.

it will be understood that such an engine would stop automatically if lubricating oil ceased to be present or dropped to too low a level in crank-case 6, and this constitutes a safety feature of my device.

The means for placing the reservoir periodically in communication with the power cylinder andwith the pump are as follows: j

On the one hand, a rotary valve 2t located downstream of cylinder 11 with which it is connected by a pipe 13, this valve 2%) being rotated at a speed equal to one half of that of crankshaft 5, for instance by the shaft, which controls the ignition system of the engine. I I

And, on the other hand, a check valve 17, for instance a ball valve located upstream of pump 7 and disposed so as to allow only the how of liquid from casing 6' to' the pump and to prevent any discharge of the pump directly, into said crank-case.

Fig. 2 shows a modification of the rotary valve device of valve the opening 22 of which periodically places pot r v cylinder 11 into communication with reservoir 6. This devices works in the following manner:

Fig. 1 corresponds to the end of the compression strok of piston 2. Flunger 8 is then at the end of its inward stroke. pipe 18 to pipe 14.

During the next half revolution of shaft 5, which corresponds to the power stroke of piston 2, cam 19 allows plunger 8 to be pushed outwardly, i. e. toward the right, by its spring 9 (return stroke of plunger 8), thus exerting a suction on the liquid in the oil circuit 7. Since valve 20 is' then cutting off the connection between pipe 18 Valve Zii has just closed the outflow of oil from and pipe 14 and the engine exhaust valve 3 is also closed during this stroke (and therefore valve stem 12 cannot be drawn in any more into cylinder 11), oil can flow into the circuit only through pipe from reservoir 16 past check valve 17 which opens.

During the next half revolution of shaft 5, which corresponds to the engine exhaust stroke, valve still cuts off the connection between pipe 18 and pipe 14. Cam 19 moves piston 8 inwardly against the resistance of spring 9. Since check valve 17 prevents backfiow of oil toward reservoir 16 and since oil cannot escape past valve 20, the oil pressure is transmitted to valve stem 12 and exhaust valve 3 opens.

During the next half revolution of shaft 5, which corresponds to the suction stroke, valve 20 still cuts off the connection between pipe 18 and pipe 14. Cam 19 allows plunger 8 to move outwardly with respect to cylinder 7 under the effect of spring 9 (return stroke). This increase of the volume of liquid inside cylinder 7 is compensated by the reduction of the volume of liquid which results from the inward movement of valve stem 12 under the action of spring 13 to close exhaust valve 3. Therefore check valve 17 does not open since, normally, there is no inflow of oil from reservoir 16 to pipe 19.

During the next half revolution of shaft 5, which corresponds to the engine compression stroke, plunger 8 is again pushed back by cam 19 into cylinder 7. This of course causes check valve 17 to close. But valve 20 now opens the connection between pipes 18 and 14. Exhaust valve 3 remains closed under the effect of its spring 13.

The cycle is now finished and the above operations are repeated.

Thus, on every four stroke cycle of the engine, some amount of oil will be discharged through pipe 10 into power cylinder 11, a corresponding surplus of oil being driven out from said cylinder 11 through pipes 18 and 14 back into reservoir 16. This oil circulation cools down valve stem 12, return spring 13 and the housing of valve 3. The active oil present in the pump, the power cylinder and the pipes is thus constantly renewed.

Of course, the operation of the valves has been described in a diagrammatic manner without making allowance for the lead to ignition and other leads which practically exist. However, the above description would remain practically the same with a cycle of this kind. In a multi-cylinder engine, the plunger pistons 8 are of course disposed around cam 19 making with one another an angle depending upon the number of cylinders, and being arranged in a manner corresponding to the order in which ignition takes place. When several valves are to be opened simultaneously, as it is often the case with engines including a great number of cylinders, a single pump 7 with its plunger 8 may control these valves.

Such a hydraulic control device has many advantages. In particular, the shape of the control cam (19) which is made to work over a portion of a circumference twice greater than in the case of known devices, leads to a mechanical efiiciency which is much higher than what has been obtained up to now. It makes it possible to obtain for the valves the best possible laws of acceleration. Absorption of the vibrations of the valve springs is achieved owing to the fact that they are moving in a liquid under pressure.

Of course, my device might be applied to a two stroke internal combustion engine. In this case, the pump would be controlled by a cam shaft rotating at a speed equal to twice that of the crank shaft and the valve 20 would be mounted on a shaft rotating at a speed equal to that of said crank shaft.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. In an internal combustion engine including at least one cylinder, a piston movable in said cylinder, a crank shaft, means for interconnecting said piston with said crank shaft, and at least one inlet valve and one exhaust valve for said cylinder, a device for controlling one of said valves, which comprises, in combination, a piston operatively connected with said last mentioned valve, a reservoir of liquid, a closed circuit for said liquid having both its inlet and its outlet in said reservoir, a power cylinder for said valve operating piston inserted in series in said circuit, a reciprocating piston pump operatively connected with said shaft inserted in said circuit between the inlet of said circuit and said cylinder, and means for causing said valve operating piston on one reciprocation thereof to operate said valve and on the next reciprocation to circulate oil or any other liquid used for the valve control always in the same direction through said circuit, whereby the control liquid in contact with the valve control piston is constantly renewed.

2. In an internal combustion engine including at least one cylinder, a piston movable in said cylinder, a crank shaft, means for interconnecting said piston with said crank shaft, and at least one inlet valve and one exhaust valve for said cylinder, a device for controlling one of said valves, which comprises, in combination, a piston operatively connected with said last mentioned valve, a reservoir of liquid, a closed circuit for said liquid having both its inlet and its outlet in said reservoir, a power cylinder for said valve operating piston inserted in series in said circuit, a reciprocating piston pump operatively connected with said shaft inserted in said circuit between the inlet of said circuit and said cylinder, valve means operative in response to the reciprocating movement of said engine piston for closing said circuit simultaneously between said circuit inlet and said pump and between said cylinder and said circuit outlet during one inward stroke and the next return stroke of said pump piston, for opening the connection between said cylinder and said circuit outlet while closing the connection between said circuit inlet and said pump during the next inward stroke of said pump piston and for closing the connection between said cylinder and said circuit outlet while opening the connection between said circuit inlet and said pump during the next return stroke of said pump.

3. In an internal combustion engine including at least one cylinder, a piston movable in said cylinder, a crank shaft, means for interconnecting said piston with said crank shaft, and at least one inlet valve and one exhaust valve for said cylinder, a device for controlling one of said valves, which comprises, in combination, a piston operatively connected with said last mentioned valve, a reservoir of liquid, a closed circuit for said liquid having both its inlet and its outlet in said reservoir, a power cylinder for said valve operating piston inserted in series in said circuit, a reciprocating piston pump operatively connected with said shaft inserted in said circuit between the inlet of said circuit and said cylinder, a check valve between said circuit inlet and said pump, and valve means inserted in said circuit between said cylinder and the outlet of said circuit operatively connected with said shaft to be opened only on every second inward stroke of said pump piston.

References Cited in the file of this patent FOREIGN PATENTS 12,523 Great Britain July 11, 1921 803,839 Germany Apr. 12, 1951 804,001 Germany Apr. 16, 1951

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