US 1967734 A
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July 24, 1934. E. G. BAKER INTERNAL GOMBUSTION ENGINE Filed July 9, 1931 2 Sheets-Shea?l l 22 W7@ iff July 24, 1934. E, G, BAKER 1,967,734`
INTERNAL COMBUSTION ENGINE Filed July 9, 1951 2 'Shee's-SheefI 2 ff f4 we, my
Patented July 24, 1934 UNITED STATES PATENT QFFC 3 Claims.
My invention is concerned with rotary-valve mechanism for internal combustion engines, and
it is my object to produce such a mechanism in which the rotary valve will adequately coniine the gases under pressure in the engine in order t0,` prevent leakage and loss of power; in which the valve will at all times run freely without scoring in the casing which encloses it; and in which oil will be definitely excluded from contact with the gases that pass through the engine, whereby to prevent the formation of smoke resulting from burning or heating of any such oil.
In carrying out my invention I may provide separate valves for inlet and exhaust gases, these valves being respectively mounted in bores in the cylinder head, which bores communicate, preferably through a common port, with each cylinder of the engine. The gases are fed and removed from the engine through axial passages in the rotary valves, the communication between such passages and the engine cylinders being controlled by ports in the valve, such ports passing intov and out of registry with the cylinder ports as the valves are rotated. My invention may also be embodied in a single rotary valve, in which case the inlet and exhaust passages will be located exteriorly of the'valve. The valve, or at least those portions of it which contain the valve ports, are formed of carbon, as'will be more particularly set forth hereinafter. Associated with the valve is means for forcing it to seat during the periods in which it is closed in such a Way as to preventleakage of gases during the power` stroke of each cylinder of the engine. To prevent scoring, I provide means for imparting an axial reciprocation to the valve as it rotates.
The accompanying drawings illustrate my invention: Fig. 1 is a longitudinal section'through one valve of a two-valve engine; Figs. 2 and 3 are transverse sections on the lines 2-2 and 3--3 of Fig. 1 respectively; Fig. 4 is a fragmental section on the line 4 4 of Fig. 3; Fig. 5 is a longitudinal section on the line 55 of Fig. 6 showing the valve of a single-valve engine; and Figs. -6 and 7 are transverse sections on the lines 6-6 and "7--7 of Fig. 5 respectively.
'The engine with which my device is associated may have any number of cylinders 10 the upper V'ends of which are closed by ahead l1 which ccntains the valve mechanism. As shown in Figs. 1 and 2, the head is provided with two parallel valve-receiving bores which extend parallel to the cylinder block and which .are located on opposite sides of the plane containing the cylinder 55 axes, as is clear from Fig. 2. The head 10 lis provided with `a combustion Chamber 12 for each cylinder, such combustion chamber communicate ing with both bores in the cylinder head through a centrally located port 1 3.
Each of the bores in the cylinder head 1l cone QQ@ tains a rotary valve preferably formed` of a single piece of tubing 14 which extends for the length of the head and is mounted at its ends in suitable bearings which support it concentric with the associated bore. Opposite each cylinder, 657; there is mounted for rotation with each of the tubes 14 ay sleeve l5 the outer diameter of which is such that each tube 14 with its associated sleeves can rotate freely in the bore which IeC-ves it. Ports 16 are provided in Jdie tube 1 4 and 'in each. m of the sleeves 15, these ports being arranged to pass into and out of registry with lthe cylinder port 13 as the valve rotates. Preferably, each of the sleeves has two ports located diametrically opposite each other, as indicated in the drawings; 15;. but this particular number` of ports is not essential.
The sleeves A15, in the preferred formof my invention, are formed of carbon of the general type used for brushes in electrical machinery. ag, This material is fine-grained, requires no lubri.- y cation; and will not score the surface of the bore in which the sleevesl l5 are located. Further,
I have found that by making the sleeves 15 of carbon they will not, as the result of dimensional changes resulting from variations in temperature, bind inthe bore which receives them 0r become loose therein to permit the escape of gases, nor will they deteriorate under the high temperatures to'which they are subjected.y
For the purpose of holding each of the ,Sleeves 15 in place on the tube 14, I may employl the means illustrated in Fig. 1. i
This means comprises a collar 20 located at each end of the sleeve `15 and l10n-.rotatably secured thereto as by being provided on one face with extensions 21 which are received in radial slots 22 in' the end face Qf the sleeve, the other face, each of the rings 20 is provided with one or more radial slots which receive teeth 23 on a ring 24 which is rotatable with the tube 14 and which preferably is keyed thereto. This QOH.- struction insures that each sleeve 15 will occupy a constant angular position o n the tube 14 and will rotate with the tube to provide the opening and closing of l the Vcylinder ports ,necessary to engine operation.
Each .of the collars 2.0 adjacent the abutting face of the associated sleeve 15 is provided with an annular rabbet groove 2,5 which groove Areceives a sealing ring 26. The axial thickness of the sealing ring 26 is slightly less than the width of the groove 25 which receives it, and that face of the ring which is disposed adjacent the associated sleeve 15 is countersunk for a purpose which will hereinafter become apparent. The opposite face of the sealing ring 26 and the abutting face of the collar 20 are accurately machined to have a close fit.
The sealing rings 26 are preferably of material having a higher coeflicient of expansion than the material of the head 1l. If the head l1 is formed of steel or iron, the sealing rings 26 may be of bronze. The outer diameter of the rings 26 is such that when both they and the cylinderV head are cold the rings will have a close fit in the valve-receiving bores.
The construction just described provides an effective seal preventing axial escape of gases from the port 16 between the sleeves 15 and the surface of the valve-receiving bore. Any such gas which tends to escape axially along the outer surface of the sleeve will enter the pocket provided by the counter-sunk face of the ring 26, entrance of the gas to this pocket being made possible by reason of the fact that the axial thick ness of the sealing ring is less than that of the groove in which it is located. The pressure of the gas in this pocket tends to force the sealing ring 26 outwardly into firm engagement with the adjacent face of the groove in the collar 20 to prevent the escape of gases between such surfaces. y As the engine runs and the temperature increases, the rings 26, being of a material hav ing a higher co-eflicient of expansion than that of the head, will expand into firm frictional engagement with the surface of the face-receiving bore to prevent any possibility of leakage past the ring. In the operation of the engine, the rings 26 remain stationary, while the sleeves 15 and collar 20 rotate.
For the purpose of preventing circumferential leakage of gases, particularly during the power stroke in each engine cylinder, I provide means for forcing the sleeves 15 into close contact with the inner surface of the valve-receiving bore over the region adjacent the cylinder port during the "power stroke in the cylinder.
To this end, each of the collars 20 is provided with cam lobes 30, there being one of such lobes `for each port in the associated sleeve 15. At a point in the cylinder head 11 across each valve'- receiving bore from the cylinder port, I provide cam followers in the shape of rollers 31 which bear upon the collars 20 in the plane of the lobes '30. These rollers are spring-pressed inwardly as by means of springs 32, with the result that the springs 32 tend to deect the valve toward vthe cylinder ports. The cam lobes 30 are so angularly disposed relative to the ports 16 that one of the cam lobes 30 engages the roller 31 during the power stroke in the adjacent cylinder. As the cam lobe forces the roller 3l outwardly against the pressure exerted by the spring 32 during the power stroke, the sleeve 15 is forced into close contact with the wall of the bore in which it is located in the region surrounding the adjacent cylinder bore. Y
For4 the purpose of lubricating those parts of the valve mechanism which require lubrication, I provide an oil supply header 35 which receives oil from the lubricating system of the engine. At spaced pointsin its length, this header is connected through pipes 36 with the valve-receiving 4bores in the head 11 at points between two adjacent sleeves 15 and at the ends of the valves. The
not come into contact with the sleeves 15 andcannot become mingled with the gases passing' through the engine to create smoke.
The manner of operating valves 14 is subject to considerable modification. The engine illus1 trated in the drawing is assumed to be a fourstroke cycle engine; and as the valves have two ports for each cylinder, they are rotated at onequarter engine speed. Conveniently, the valves are interconnected by gears 40 of equal size and one of the valves is driven by a sprocket and chain drive .4l from the engine crank-shaft.
Gases are supplied to the inlet valve and removed from the exhaust valve by means of conduits each of which communicates with its associated valve through the opening in the end thereof. 'I'he opposite end of the valve is closed 'to prevent the escape of gases therethrough.
Figs. 5 to 7 illustrate a modiiication of my invention shown as embodied in a single-cylinder engine, although it is of course not limited to use in a single-cylinder engine. In this arrangement, I employ a single valve instead of the two valves shown in Figs. l to 4, and instead of providing a gas-conduit within such valve, I locate the gas conduits in the cylinder head.
The single valve comprises a cylinder of carbon which is rotatably received in a recess of corresponding diameter conveniently disposed above the cylinder and parallel to the engine crank-shaft. The cylinder has a single gas port 13, while the valve-receiving bore has approximately diametrically opposite ports one of which communicates with the'inlet conduit 52 and the other of which communicates with the exhaust conduit 53. In the transverse plane of these lastmentioned ports, the valve is provided with re.- cesses 54 which, in the rotation of the valve, provide passages affording intermittent communicationbetween the cylinder-portlS and the inlet and exhaust ports of the valve-receiving bore.
In association with ythe valve just described I may employ means for forcing the valve against its seat adjacent the cylinder port 13AV during the compression and explosion strokes of the engine piston. 'Ihe means illustrated in Figs. 5 to '7 is very similar in principle to that previously described in that cams rotatable with the valve and associated with spring-pressed followers are used. The cams are conveniently formed in the carbon body of the valve 50, by providing diametrically opposite grooves 55 near each end of the valve. In the plane of each of these grooves thereis radially slidably mounted in the cylinder Sgr head'opposite the port 13 a shoe 56. Above the @1335 shoe 56 is located a compression spring 5'7 which tends to move the shoe downwardly into Contact with the valve 50. The spring 57 is of such a length that when one of the grooves V55 is beneath the reaction will rmly seat the'valve adjacent 145 the port 13.
The valve 50 may be driven from a drive shaft 60 which is rotatably mounted co-axial with the valve and which may be provided at one end with a sprocket 61 through which it may be driven, (at @E50 one-quarter engine speed, in a four-stroke cycle engine). On its opposite end, the valve-driving shaft 60 is provided with a transverse key 62 adapted to be received in a transverse slot in one end of the valve 50.
I have found that in a rotary valve of the type described the amount of wear and any tendency to score may be materially reduced by reciprocating the valve axially as it rotates. 'Io this end, I may provide the shaft 60 adjacent the key 62 with a flange 63 which overlies the end of the valve 50, and the outer surface of which is formed at an angle to aplane perpendicular to the axis of the valve. In position to cooperate with this inclined outer face of the flange 63 I mount a stationary button 64, and yieldingly press the flange 63 into engagement with such button as by means of a compression spring 65 which acts against the opposite end of the valve 50. As the valve rotates, the inclined outer face of the flange 63, cooperating with the stationary button 64, acts as a cam and produces one complete axial reciprocation of the valve for each revolution thereof.
While I have referred above to valves formed of pressed carbon, I do not wish to be understood as limiting myself to such valves of which carbon forms the sole ingredient. In addition to carbon, the valve may embody nely powdered metals which are intimately mixed with the carbon prior to the formation of the block from which the valve is machined.
I have found that rotary valves constructed so as to present a carbon wearing surface adjacent the cylinder port or ports withstand, without the necessity for any lubrication, the Wear and heat to which they are subjected in service. Such valves, after hundreds of miles use in a motor-cycle engine, show no detectable wear and have a glass-smooth exterior surface. I believe this result to be due largely to the intermittent pressure to which the valve is subjected in operation coupled with the fact that a certain amount of finely divided carbon is freed in the engine cylinder and deposited on the valve surface which is exposed at the cylinder port. The fact that radialpressure on the valve is intermittently relieved during valve-rotation would give any such deposited carbon an opportunity to become evenly distributed over the valve surface before it became embedded therein.
I claim as my invention:-
1. In a rotary valve mechanism, a rotary valve element having one or more ports, a ported casing surrounding said valve element, a cam rotatable with said valve element, a cam follower mounted in said casing for radial movement toward and away from the valve element, and yielding means for forcing said cam follower toward engagement with said cam.
2. The invention set forth in claim 1 with the addition that there are two of said Cams spaced apart axially of the valve element and located on opposite sides of the casing-port, there being a cam follower associated with each of said cams and said cam followers being independently movable.
3. In an internal combustion engine having a cylinder provided with a gas-passing port, valve mechanism for controlling the flow of gases through said port, said mechanism including a rotatable valve member, and means for causing axial reciprocation of said valve member as it rotates, said means comprising a cam rotatable with said valve, a stationary part co-operating with said cam, and yielding means acting on said valve and tending to maintain engagement of said cam and stationary part.
ERWIN G. BAKER.