US1746227A - Hydraulic valve mechanism - Google Patents

Description

Feb. 4, 1930. J. o. ALMEN 1,7 7

HYDRAULIC VALVE MECHANISM Filed March 14, 1928 2 Sheets-Sheet l gwvemtoc Feb. 4,' 1930. .1. o. ALMEN HYDRAULIC VALVE MECHANISM v 2 Sheets-Sheet 2 Filed March 14, 1928 Watcte li e. a 3111i JUHN U. ALMIEN, UF ROYAL lilti MICHIGAN, SIGNOR 130 GENERAL MOTORS RE- GHJLGAN; A CORPOBATIQN 01E DELAWARE application filed Maren 1a, 1928. serial lt'o. $61,525.

This invention relates to hydraulically operated valve gear for internal combustion engines.

Systems for hydraulically operating valve gear have previously been proposed in which each valve has been operated by means of an hydraulic column moved by a. plunger or other fluid displacing member. Such systems are open to the criticism that there is undue complication since each valve is provided with a separate plunger andhydraulic chamber, and each chamber must be oil tight and must be equipped independently with means for supplying it with oil.

Another system has been proposed in which a supply of oil under pressure communicates with a distributing valve arranged at the proper time in the engine operation to connect the oil supply with a fluid column to displace 2a the latter and unseat the valve. To enable the valve to return to its seat under spring action, the distributor valve is moved to a position where the fluid supply is cut off and the column is vented to permit discharge of excess oil. This system is objectionable in that the impulse given the hydraulic column is too abrupt so that the valve opens too quickly and seats too quickly, producing noisy operation.

My improved hydraulic valve operating system is of the type first described in that the valve follows the movements of the operating plunger but is greatlylsimplified in that a single operating plunger controls several different valves, these valves being so related in their 0 ening and closing movements and the pump eing driven. at such speed asto actii:

ate the valves in proper sequence. Obviously a single operating plunger can only take care of valves whose opening and closing periods do not overlap but where this condition is fulfilled the pump may take care of any number of valves. In my improved system a distributor is provided to direct the pump impulses to the valves in proper sequence.

My invention has particular advantages in the case of a six-cylinder engine in which the opening and closing period of the valve occupies 240 of crankshaft rotation. Here each 60 pump may handle three valves whose timing does not overlap. Consequently but four pumps and four distributors are required for the engine and, since each valve follows the pump plunger throughout its cycle of movement, the opening and closing movements of the valve are very gradual and do not produce noise.

Like all hydraulic operating systems the present system possesses the advantage that the fluid column adapts itself by increase or decrease in volume to the varying degree of contraction and expansion of the parts resulting from heating so that quiet operation is insured under all conditions. that the system may function in this manner it is of course necessary to provide a connection with a source of supply of fluid and this is best done by connecting each pump with the lubricating system of the engine, a non-return valve ensuring against the discharge of oil into the crankcase on the actuating stroke of the pump.

Figure 1 is a vertical section through an internal combustion engine embodying my improved valve operating system.

Figure 2.-is a top plan view of the engine. Figure 3 is a section on line 3-3 of Figure 2. m

Figure 4 is a section on line H of Fig: ure 3.

10 indicates an internal combustion engine comprising cylinders 12 within which reciprocate pistons 14. connected to crankshaft 16 in the usual manner. The engine illustrated is of the six cylinder type, each cylinder being provided with an intake valve and an exhaust valve. I have illustrated one such valve at 18 in Figure 1, the valve being normally held on .its seat by coil spring 20. Above the stem of each valve is located a cylinder 22 in which is fitted piston 24: which may or may not be integral with the valve stem as preferred. The cylinder 22 is connected by conduit 26 with distributor 28 which controls the connection of the conduit 26 with the circuit 30 leading to the pump 32. t In Figure 2 I have indicated the arrangement of the valves. The intake valves are denoted by the letter I and exhaust valves by the letter E. Each cylinder is provided In order q the istributors 28 by means of with an inlet and an exhaust valve as previously stated and in the type of engine illustrated the timing is such that the period of opening and closin of each valve corresponds to 240 of crankshaft rotation. The firing order is also such that beginning at one end of the block the first three intake valves are operated in sequenceas are also the first three exhaust valves. With this arrangement "during two complete revolutions of the crankshaft, that is 720 of crankshaft rotation, each set of three intake or exhaust valves is opened and closed in succession. To accomp ish this movement by means ofa liquid column operated by a pump the pump must make an intake and an exhaust stroke, in other words complete one cycle, during, each 240 of crankshaft rotation. This means that the pump 32 must be driven at one. and one-half times crankshaft speed. The distributing valve shown at 28 must connect the pump with each valve cylinder 22 in turn and consequently must make but one revolution during each two revolutions of the crank shaft. The pumps and distributors at one end of the engine carin for the six valves at that end may be simp y driven in the following manner.

spiral gears 36 of such ratio that shaft 34 is driven at one and one-half times crankshaft speed. To the shaft 34 is secured crank 38 carrying pin 40 and to the pin are connected rods 42 operatin the istons 44 of the umps 32. The shaft 34 li ewise drives spur gearing 46 such that the distributors are driven at one-half crankshaft speed. Each distributor consists simply which rotates disk 48 driven by the gearing '46. The disk 48 is cut away at 50 to establish communication between the space 52, between the top of the disk 48 and the distnbutor houslng and the ports 26 leading to the valves. The disk 48 uncovers the outlet to each conduit 26 in succession. With the space 52 communicates the conduit 30 previousl described leading to the pump 32. The istributor thus serves to connect the pump chamber successively with the exhaust or the intake valves of adjacent cylinders so that the motion 'of the pump is at all times utilized in operating one or the other of the valves. The arrangement of pumps, distributors and conduits at the other end of the engine is identical with that described.

Each pump chamber is provided with a connection leading to a suitable source of oil supply and controlled by a non-return valve 62. The simplest way is to make connection with the circulating lubricating system of the engine.

With the described construction, during each revolution of the shaft 34 each pump 32 will complete one cycle of movement. Dur- 34 indicates a vertical shaft & driven from the crankshaft 16 by means of of an annular casing 47 in L ing this cycle of movement the distributor disk 48 wi 1 be in such osition as to connect the pump chamber with one of the conduits 26 leading to a cylinder 22. On the discharge stroke oil will be forced from the pump chamber through conduit 30, passage 52, passage 50 and conduit 26 into the cylinder 22 forcing the plunger 24 downwardly unseating the valve. place gradually, chronism with the pump. Upon the return stroke of the pump, the valve spring 20 will return the valve to its seat, the return movement being cushioned by the receding body of oil. Upon completion of the return stroke the disk 48 will have assumed a position in This motion will take the valve moving in syn-- which communication with the conduit 26,

leading to the valve, just operated, is cut off and in'which communication is established between the pump chamber and the conduit 26 next in order of rotation of the distributor.

'With this arrangement upon completion of one rotation the distributor will have con nected the pump chamber with each of the three valves, and the pum will have performed three complete cyc esof movement produced by three complete rotations of shaft 34. Should there be a shortage of oil in the system the suction stroke of the pumpwill cause oil to be drawn in through the conduit 60 to replenish the supply.

The above described system possesses all the advantages of the more complicated systems in which a separate pump is provided for each valve and at the same time sacrifices no smoothness of operation for the movements of the valve are gradual following the movements of the pump piston.

It is obvious that the number of valves which may be operated by one pump is limited by the number whose cycles of movement do not overlap. However, it is not essential that the valve timing be exactly 240 although this is desirable to permit the use of a crank operated pump. Other valve timing may be employed'by providing cam operation for the pump, the cam being provided with a hump for producing the desired movement of each valve. In such event the cam shaft would be operated at distributor valve speed.

I claim:

1. Hydraulic valve operating system for six cylinder, four cycle internal combustion engines 240 valve timing comprising a hydraulic column for actuating each of said valves, a positively driven piston type pump having a cycle of movement comprising an intake stroke and a discharge stroke, and a distributor for each set of three successively operating valves, said distributor controlling communication between the pump and the hydraulic columns, and said pump being driven at such speed as to complete one cycle of movement during the period of opening iener and closing of each valve so as to efiect gradual unseating and seating thereof.

2. An internal combustion engine provided with reciprocating valves and with hydraulic valve operating mechanism comprising pistons for operating the valves, cylinders in which the pistons operate, a shaft driven by the engine, a pump comprising a cylinder and a piston, a connection between the driven shaft and said piston for positively operating the latter, a distributor driven from the engine, a conduit connecting the pump cylinder and distributor to supply working fluid 'thereto, a plurality of conduits each connecttit ing the distributor with one of the first named cylinders, said conduits being arranged to divert Working fluid to Valves operating in sequence, said distributor being arranged to connect the first named conduit with each of the second named conduits in sequence and throughout a complete cycle of movement of the pump comprising an intake stroke and a discharge stroke.

In testimony whereof ll afiix my signature.

JOHN O. ALMEN.

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