US3528394A - Internal combustion engine - Google Patents

Description

United States Patent [72] Inventor Clessie L. Cummins P.O. Box 785, Sausalito, California 94965 [21] Appl. No. 704,115 [22] Filed Feb. 8, 1968 [45] Patented Sept.15,1970

[54] INTERNAL COMBUSTION ENGINE 22 Claims, 20 Drawing Figs.

[52] U.S.Cl 123/58, 123/51, 123/189, 123/196, 184/6 [51] Int. Cl. F02h 75/26, FOlm 1/06, FOls 3/00 [50] Field ofSearch 123/58,51, 189, 65U4; 123/196; l84/6P [56] References Cited UNITED STATES PATENTS 780,549 1/1905 Callan 123/58X 781,802 2/1905 Barber 123/189 1,166,714 1/1916 Ramesh... 123/51 1,206,715 11/1916 Jones 123/51 1,378,333 5/1921 Drevet. 123/51 1,390,416 9/1921 Wolf 123/51 1,543,113 6/1925 Lleo etal.... 123/58 1,601,344 9/ 1926 Burtnett ..123/65(U4)UX 2,236,738 4/1941 Swensen 123/58 2,263,561 11/1941 Biermann.. 123/58X 2,332,105 10/1943 Neuland.... 123/58 2,332,106 10/1943 Newland l23/58X 2,354,620 7/1944 Smith 123151}? 746,925 12/1903 Crane.. 123/5l(A)UX FOREIGN PATENTS 513,999 /1939 Great Britain".. QZC 11/1930 Germany 123/90(E)UX 5/1954 Switzerland ..123/51(Al)UX 104,307 6/1938 Australia 123/5l(A)UX 448,421 11/1912 France ..123/58(B3)UX 496,541 7/1954 Italy l23/51(A)UX Primary ExaminerWendell E. Burns Attorneys Owen, Wickersham and Erickson ABSTRACT: This two-cycle or four-cycle Z-crankshaft engine has several pairs of opposed pistons symmetrically reciprocating in open-end cylinders. The combustion chamber lies mainly to one side at the center of each cylinder in an exhaust-valve housing, which also carries the exhaust and intake ports. Where fuel injection is used, a flat fan-like spray. substantially fills the flat generally fan-shaped combustion chamber. The exhaust-valve housing, intake-valve cage and a pair of stem-aligning assemblies are removable as a unit with their valves, for maintenance or repair or replacement, with subsequent disassembly quite simple. A simple, oblong ring gasket between the exhaust-valve housing and the cylinder casting is the only gasket at or near the combustion chamber, and it is quite small in area. Timing of the valves and injector or ignition is by a cam-operated hydraulic system. A pair of novel converter units on the Z-crank-shaft takes off the power from the pistons and converts the thrust of the pistons into torque. A force-lubrication system with a pair of dry sumps insures wear-reduction. The Z-crankshaft itself is assembled from the converter units, some crank-webs, and a tubular cylindrical shaft, in a manner enabling inexpensive machining and manufacturing costs. The complete engine is also readily assembled from relatively inexpensive components; each cylinder can be a separate and relatively inexpensive casting, as can be each intake-valve cage and exhaust-valve housing, and all such cylinders are identical, as are all intake-valve cages and all exhaust-valve housings. A novel engine brake may be, included.

Patented Sept 15, 1970 3,528,394

INVENTOR. CLESSIE L. CUMMINS ATTORNEYS Patented Sept 15, 1970 Sheet ATTORNEYS Patented Sept. 15, 1910 3,528,394

Sheet 4 of 11 1:25 64 f i f 69 i 6768 43 l l 67 I I m I 44 68 INVENTOR. CLESSIE L. CUMMINS ATTORNEYS Patented Sept. 15, 1970 3,528,394

Sheet 5 of 11 IO 03 o 00 m m l (9 m E N 00 to N INVENTOR.

ATTORNEYS CLESSIE L. CUMMINS Sheet 6 of 11 RESERVOIR INVENTOR. CLESSIE L. CUMMINS 0L, MM'M ATTORNEYS Patented Sept. 15, 1970 Sheet ATTORNEYS Patented Sept. 15, 1970 3,528,394

INVENTOR. y CLESSIE L. CUMMINS 001%. u/M flelzie.

VAITQRNEYS Patented Sept. 15, 1910 3,528,394

Sheet 9 of 11 /lllllll llllllln INVENTOR. CLESSIE L. CUMMINS BY 0 MM 5% ATTORNEYS INTERNAL COMBUSTION ENGINE This invention relates'to an improved internal combustion engine of the type in which two opposed pistons move symmetrically in each cylinder toward and away from each other.

The engine of this invention is a radical departure from conventional internal combustion engines and contains many novel features, including novel cylinders, the combustion chambers, the valve housings and assemblies, the Z- crankshaft, the cam-actuated hydraulic timing and actuation of valves and injectors or igniters, and the lubrication system.

Conventional engines have had to be relatively bulky and heavy, and have required large, heavy engine blocks, which have been very expensive to manufacture, and have required a great many expensive machine tools. The present invention has among its objects the provision of an engine which is small in bulk relative to its power, is light in weight relative to its life, is relatively free from vibration, enables the use of many identical parts, and has no large, heavy engine block and therefore does not require the manufacturer to maintain a heavy extensive line of machine tools. This object may be achieved partly by the use of a separate casting for. each cylinder, all identical, and by separate and identical castings for each exhaust-valve housing and for each intake-valve cage, and by a novel assembled Z-crankshaft with novel converter plates.

Maintenance has long been a problem with engines and has been expensive whenever it involved the removal and replacement of the valves, because this usually involved the dismantling of the engine head, replacement of gaskets, etc. Other objects of the present invention therefore, are to provide an engine which costs less to maintain, and for which minor repairs, including valve jobs, are relatively inexpensive. The present invention enables the removal and replacement of the valves without having to dismantle an engine head and related parts-since there is no engine head, as the term is usually used-and its eliminates head-gasket troubles.

Heretofore, diesel engines had difficulties because the cylinder head could be no larger than the bore, so that the area was too small to give the needed area for air ports and valves, and the problem was aggravated by having to put the fuel injector in the center of the two or four valves, in order to obtain high performance. Such crowding of injector and valves tended to weaken the head, and eventually often resulted in a bad crack that ruined the head. My new invention, as applied to a diesel engine, provides a combustion chamber having two sides, one for intake valves and one for exhaust valves, both unencumbered by an injector, which is located in an end wall and gives even more efficient burning than in conventional diesels. Moreover, the valves can be as large as desired without seriously weakening the combustion chamber walls, and the injector can be as large as desired and can therefore be properly designed to afford adequate room for all of its component parts.

Hence, whereas diesel engines heretofore had to rely on costly blowers or superchargers to force enough air through their restricted intake valves, my invention produces more power than prior-art diesel engines without blowers or superchargers, and a blower or supercharger can be used, if desired, to get still more power than prior-art supercharged engines Also, the prior-art locationof the infctor between the valves has required compromises as the space consumed by the valves and the injector, usually causing both to suffer and at the same time weakening the head castings, where the highest heat and stresses are found. The life of injector check valves and other injector parts has been shortened. In my invention, the injector is located in a separate wall where the right size and shape is' available, and both the valves can also be the optimum size, for each has its own wall-an injector wall, an intake-valve wall, and an exhaust-valve wall. The fourth side is open to a space in the cylinder between the two pistons. This structure confines the fuel-air mixture into a limited space of such size and shape as give the highest combustion efficiency.

One of the problems with current engines has been their relatively inefficient combustion in comparison with what is theoretically possible. This has been due partly to incomplete combustion, partly to the large heat losses involved, and partly to combustion losses and other loss factors tending to reduce the effective power of the engine relative to the amount and quality of combustion that is obtained. An object of the present invention is to greatly improve the efficiency of combustion, to reduce heat losses to the exhaust and to the engine cooling system, combustion losses, friction losses, and other loss factors that have reduced power, and thereby to increase the engine efficiency. Better injection equipment improves combustion, smaller bearing area reduces friction losses, and

the side thrust in the pistons is substantially eliminated. The net result is much lower fuel consumption for a given power output.

It is now widely recognized that the large area occupied by combustion chamber linings has been a major source of smogproducing gases and vapors. In conventional engines cold fuel particles have struck these linings as atomized liquid particles and could not burn until they were vaporized, and their vaporization often took place so late in the power stroke that the exhaust valve was then open, and the smoldering fuel went out into the air unburned-a significent source of smog. Hence, reduction of the wall area of the combustion chamber is very desirable. It is accomplished in my invention by doing away with the conventional cylinder heads. In their place are provided the opposed pistons, each of which serves as a head for the others. They nearly touch at the peak of their compression strokes. The compressed air is thus forced into a flat, engineered chamber of optimum shape for the best combustion. The present invention makes possible a reduction to a minimum of the area of the combustion chamber for any given size of engine, with a consequent lowering of the fuel consumption.

Also, in a gasoline carburetor-type engine of this invention, where the fuel-air mixture enters through the intake valves, it is projected across the narrow combustion chamber against the very hot exhaust valves and the very hot walls surrounding them, so that the fuel is more quickly vaporized and burned. As a result, in a carbureted gasoline engine of this invention more of the introduced fuel is converted into useful power and less into noxious, smog-producing gases. A further beneficial result is that the cool fuel-air mixture has the effect of cooling the hot exhaust valves, thereby adding to their life.

In a fuel-injection engine of this invention, the fuel is introduced as a flat fan-shaped spray that fills the flat fan-shaped combustion chamber evenly giving cleaner and more rapid combustion. The chamber is reduced to the minimum volume required for the desired compression ratio.

A particular problem with engines presently in use and especially with high-compression engines has been their inability to idle smoothly except at relatively high speeds. This has been due to the fact that in such engines the cylinder heads have, due to the crank angle, had a tendency to lean away as the piston moved .on its compression stroke, and when the piston reached its top dead center and the charge was fired, then the cylinder had a tendency to rock even more in the opposite direction due to the opposite angularity of the crank. This has resulted in a vicious back-and-forth movement that has had a very detrimental effect on the engines and on their mountings, as wellas .on the vehicle or ship where the engine is installed. The problem of not being able to idle at low speeds is particularly severe in marine applications, where the engine shakes the boat so much when idling in gear that a boat has to drift into its berth with the engine out of gear and therefore with the ship practically rudderless. The present invention solves this problem and provides a new system where it is possible to idle smoothly at relatively low speeds. By including in it the new fuel system set forth in my US. Pats. Nos. 2,984,230; 2,984,231; 2,997,993; 3,119,381; 3,131,866;

3,143,104 and 3,185,140, it is possible for the pump to reduce the charge of fuel to an amount suitable for a very slow idle speed and to obtain a proper balance even during the slow idle speed.

The complexity of conventional engines is well known. For example, on a standard Cummins engine having six cylinders, there are 18 cams, 18 lower rocker-levers, 18 upper rockerlevers, 18 adjusting screws, 18 nuts, 18 push rods, and many more small parts, including rocker shafts, rocker housing castings, etc; and on eight-cylinder engines there are 24 of each of these elements. A significant object of the present invention is to provide an engine which is markedly simpler than those now in use, is also simpler to set up and to tool for initial manufacture, and is simpler in the continuing manufacturing process. In contrast to the number of parts just listed, a typical engine of the present invention has three cylinders with six pistons in themequivalent to a six-cylinder engine-and has only three cams, three master plungers, three plunger chambers, and nine hydraulic conduits-and this takes care of all the intake valves, the exhaust valves, and the fuel injector or igniter. It can be appreciated that this greatly reduces the number of parts. A five-cylinder, lO-piston engine still has only three cams, with hydraulic conduits. There are two pistons in each cylinder, and they share in common one set of intake valves, one set of exhaust valves, and one fuel combustion means, such as one injector or one spark plug system, and each of these elements can be made in a simple form without having to conquer the difficulties involved in large engine heads; moreover, their form may be more efficient as well as simpler.

A feature of the engine of this invention is that there is never any adjustment to be made to clearances between the valves and the valve actuators, since there are no such clearances with my new hydraulic system. Another feature is that the engine noise has been greatly reduced, so that there is very little sound from the operation of the various parts, and the wear rate is greatly reduced.

The actual running of the engine of this invention has demonstrated several heretofore unappreciated advantages. One concerns the internal couple present in every engine. In orthodox engines it is conceded that these internal couples can never be balanced out more than 40 percent to 50 percent. The present invention gives every indication that these couples can be substanially completely balanced out, because the engine s configuration enables design that can balance out their reciprocating forces.

To summarize the invention briefly, my new engine may be called a Z-crank, opposed piston engine. It can be operated as a four-cycle or two-cycle engine. Each cylinder contains two pistons which are opposed to each other; they move toward each other for firing and away from each other after firing. Preferably, especially for four-cycle operation, the engine has an odd number of cylinders, for example, three, five, or seven cylinders, with twice as many pistons. All the cylinders are identical, and all the pistons are identical; moreover, they are very simple in structure, resulting in elimination of the need for the large, heavy type of engine-block casting heretofore in use, though a block-casting may be used, if desired. Each cylinder may comprise a separate, rather simple casting, instead of a portion of a complex engine block in which a number of cylinders are bored. The combustion chamber of the engine is provided at the point where the two pistons meet in the center of the cylinder and extends out beyond the cylinder to one side thereof. Its shape is preferably flattened for achieving substantially ideal combustion with minimum exposed area, and to provide wide wall areas for the intake and exhaust valves. These valves are so arranged as to be easily dismounted from the cylinder without having to disturb the cylinders themselves. The structure of the valve housings is a very significant portion of the invention, as will be understood from the detailed description that follows. The timing of the valves and firing of the engine is also quite important and is quite simple, being accomplished hydraulically in a very simple manner with the aid of a minimum number of cams operating at one-half the crankshaft speed. As a result, it is quite practical to operate the engine as a four-cycle engine; twocycle operation is also feasible if desired, the cams then operating at crankshaft speed. The Z-shaped crankshaft is also novel in structure as are its thrust-to-torque converter units and its lubrication system.

Other objects and advantages of the invention will become apparent from the following description of a preferred form of the invention.

In the drawings:

FIG. 1 is a simplified view in side elevation and partly in section of a three-cylinder engine embodying the principles of the invention showing one cylinder thereof. It can be considered as taken along the line 1-l in FIG. 2, with some parts broken or omitted.

FIG. 2 is a view in section taken along the line 2-2 in FIG.

FIG. 3 is an enlarged view in elevation and partly in section of one cylinder and its associated valve assemblies.

FIG. 4 is a view in section taken along the line 4-4 in FIG.

FIG. 5 is a view in section taken along the line 55 in FIGS. 3 and 4, but showing a spark plug instead of a fuel injector.

FIG. 6 is a further enlarged fragmentary view in elevation and in section of the intake-valve assembly and adjacent parts.

FIG. 7 is a fragmentary view in elevation and in section of one of the thrust converter units and adjacent parts.

FIG/8 is a view in section taken along the line 88 in FIG. 7.

FIG. 9 is a partially exploded view in side elevation showing the intake-exhaust valve assembly and its associated cylinder.

FIG. 10 is a top plan view of the central portion of the cylinder casting showing the combustion chamber slot therein, the surrounding gasket, and the two cooling chamber openings.

FIG. 11 is a fragmentary view in section of the upper portion of the combustion chamber taken along the line 1lll in FIG. 4, showing a fuel-injector nozzle suitable for use in this invention, creating a fiat-fan spray.

FIG. 12 is a head-on view of the noule of FIG. 11 and an adjacent portion of the combustion chamber.

FIG. 13 is a simplified view in section of a three-cylinder engine, taken along the line 13-13 in FIG. 1, and omitting some parts.

FIG. 14 is an end view of one crank web. It may be considered as taken along the line 14-14 in FIG. 7, but showing only the crank web.

FIGS. 15 and -l6 are two simplified views in side elevation and partly in section of the lubrication system for the thrust converter system, the figures differing in showing two extreme positions.

FIG. 17 is a somewhat diagrammatic representation of a modification enabling use of the engine as a brake in a vehicle driven by the engine.

FIG. 18 is a view in elevation and in section of a de-aerator for use with the hydraulic control system.

FIG. 19 is a view in section taken along the line 1919 in FIG. 18.

FIG. 20 is a view of a portion of FIG. 7 showing a modified form of crankshaft structure of this invention.

The drawings show the engine in a simplified depiction, without placing stress on relatively obvious refinements of portions thereof, such as counterweighting. By way of example, a three-cylinder, six-piston engine is herein described, and it will be understood that basically the same factors with the obvious differences would apply to a five-cylinder, IO-piston engine, or to a seven-cylinder 14-piston engine.

An engine housing 9 (FIG. 1) surrounds a central crankshaft 10 and three cylinder bodies ll, 12, and 13. The crankshaft 10 carries and is driven by a pair of thrust converters l4 and 15, each of which may, for example, comprise a generally flat, generally triangular member 16 (FIG. 8). In the crankshaft 10, each of a pair of crank pins 170 (see FIG. 1) is placed at an angle between a pair of inner and outer crank webs 17 and 18, giving the appearance of a Z at each location, so that the crankshaft is herein called a Z-crankshaft. The two inner webs 17 are joined to each other by a central tubular hollow cylindrical crankshaft portion 20 that rotates inside a simple tubular housing member 21 (see FIGS. 7 and 8). Each of the thrust converters 14, is mounted on a crank pin 170. (FIG. 1) Other structures may be used, but there are advantages in the structure shown. Each inner crank web 17 (see FIG. 7) may rotate inside a simple tubular housing member 22 that may be readily assembled to the member 21, as by means of a flange 23 on each end of the member 21. The tubular crankshaft portion preferably has an end plate 24 at each end welded to the tube 20, and a central lubrication conduit 25 may extend between and preferably be welded to the end plates 24. The crankshaft portion 20 may be anchored at each end to its inner crank webs 17, as by a perforate ring 26 which may be doweled and bolted to both the end plate 24 and the crank web 17. The crank webs 17 and 18 may be both doweled to their crank pins 170, and the three elements may also be held together by a bolt 27. Each converter unit 16 may be provided with a projecting rod 28 which reciprocates in a channel provided by a stationary guide member 29, which is anchored to the main engine case 9.

Each cylinder body 11, 12, or 13 (see FIGS. 1-3) preferably provides one cylinder 30 and has two pistons 31 and 32. A more conventional type of engine block can be used, if desired, or the cylinders may be made in more than one piece. There are advantages in the single separate bodies shown. Each piston is preferably provided with a removable ball member 33 (FIG. 3) and a removable spherical-surfaced socket member 34 to receive a ball-socket member 35, and each converter unit 16 preferably has one recess 36 (FIG. 7) for each cylinder casting, in which is provided a ball member 37 and a spherical-surfaced socket member 38 that receive between them a ball-socket member 39. The two ball-socket members and 39 are joined together to provide a connecting rod 40 having a stem portion 41 between their ball-socket portions. Thus, the pistons 31 and 32 are made to reciprocate with the thrust converters 14 and 15, the power from the fuel thereby being sent to the Z-crankshaft 10 and being converted from thrust into torque.

The pistons 31 and 32 are so connected to the thrust converters 14 and 15 that they move symmetrically toward each other for compressing the gaseous charge, and then after firing are moved away from each other symmetrically. The cylinder bodies 11, 12, 13 are all identical to each other, and so are the pistons 31, 32, and so are the combustion chambers and valves, so that the description of the one cylinder 30 with its associated parts suffices for the description of all of them. Each cylinder body 11, 12, 13 may be cast and bored to provide the very simple cylinder 30 (FIG. 3) and a suitable cooling means such as a water jacket 42 (or air jacket, for air cooling) which encircles the cylinder 30 except at one side of the center. The cylinder 30 is open at both ends for free operation of the connecting rods 40. At the center of each cylinder body 11, 12, 13 on one side thereof is a flat portion 43 (FIGS. 5 and 10) which may be partly a recess and partly a boss and into this at the center is machined a narrow slot 44, around which is a gasket seat 45 (FIG. 5) that receives a suitable gasket 46- -the only gasket at the only joint in the combustion chamber 50. The slot 44 extends down less than one-half the depth of the cylinder 30 and joins with an interior portion 47 of an exhaust-valve housing 48 to provide the combustion chamber 50 for the two pistons 31 and 32.

Atop the cylinder body 11, 12, 13 (i.e., at one side of it) are the exhaust-valve housing 48 and an intake-valve cage or housing 51 (see FIG. 1), together with a pair of exhaust-valve alignment assemblies 52 and a pair of intake-valve alignment assemblies 53. As shown in FIG. 13, the cylinder bodies 11, 12, 13 can be rotated to positions such that the valve housings 48 and 51 need not be located at a radial extremity, for the sake of compactness and accessibility of parts. In line with the exhaust-valve housing 48 and alignment assembly 52 (see FIGS. 3 and 6) is a hydraulic exhaust-valve actuating assembly 54, held by a recess 55 in the engine casing 9, while in line with the intake-valve housing 51 and its alignment assembly 53 is a hydraulic intake-valve actuating assembly 56, held by a recess 57 in the casing 9. For purposes of example and in order to describe a preferred embodiment of the invention, there are dual intake and exhaust valves for each cylinder. There may be only one of each, if desired, or there may be more.

The exhaust-valve housing 48 is so constructed asto provide not only the seat retainers or ports 60 for the exhaust valves 61 but also the seat retainers or ports 62 for the intake valves 63. By having the exhaust-valve housing 48 extend past the slot 44 and past the entire combustion chamber 50, no gaskets other than the gasket 46 between the cylinder body 11, 12 or 13 and the exhaust-valve housing 48 (except for a gasket for a spark plug or the gasket-like seat of the injector) lie adjacent the combustion chamber 50, as would necessarily be the case if the exhaustand intake- valve housings 48 and 51 were to be secured together at the combustion chamber 50 itself. By preventing that juncture at this point, major heat losses are also prevented, for it is axiomatic that wherever there is a joint, wherever two separate members meet, there are necessarily barriers to the transmission of heat to the water jacket. This is an important feature of the present invention. In a typical engine of this invention, the slot 44 is about 2%" by W and the gasket seat 45 is about W wide and recessed about l/16 so that this one gasket 46 presents a very small exposed area and little bolt strength and pressure are required. Moreover, the seat 45 being recessedin the portion 43 of the cylinder casting, the gasket 46 is held snugly against being blown out through the-very small clearance between the housing 48 and the face 43. An O-ring 49 seals around the water or air jacket (FIG. 5).

The exhaust-valve housing 48 (see FIGS. 3 and 5) is a casting which has some machined surfaces. It is provided with a suitable cooling channel 63a for water or air, which is joined to the cooling channel 42 and lies on each side of the combustion chamber 50. Since the combustion chamber 50 is long and narrow with large-area flat walls, there is plenty of area for large exhaust and intake valves and ports, which are preferably in pairs. Each port 60, 62 is provided with a suitable seat 64, 65 (FIG. 6), which may which may be inserted tightly from one end or the other of the housing 48. An ex haust passage 66 (FIG. 3) leads from the port 60 up at an angle and out to a suitable manifold, not shown here.

In assembly, the exhaust-valve seats 64 (FIG. 6) are inserted through the opposite facing intake ports 62- and placed in position in the ports 60. Then the exhaust valves 61 are inserted through the intake ports 62, stems first, and put in place against their seats 64. Next the seats 65 and the intake valves 63 are placed in position in the ports 62, either together or the valves 63 inserted first. 0n disassembly, the seats 65 are taken out, then the valves 63, then the valves 61, and finally the seats 64, all through the intake ports 62. This can be done only when the intake-valve cage 51 is first removed. To enable this installation, the valves and ports need some degree of alignment. They may, as shown, all lie along axes parallel to the longitudinal axis of the cylinder 30, or they may be somewhat inclined to that axisso long as the angle of inclination does not prevent the installation and removal in the order described, once the intake cage 51 is removed. The intake valves 63 and ports 62 may be larger than the exhaust valves 61 and ports 60, and this helps in disassembly.

Both housing 48 and 51 are also provided with openings 67 (see FIGS. 4 and .6), one aligned with each valve port 60 or 62 in which a valve stem guide 68 is secured, being seated'against a shoulder 69 and having a smooth cylindrical bore 70 therethrough. Through this bore 70 a valve stem 71 extends from the head 72 of the valve 61 or 63. The stem 71 extends beyond the valve stem-guide 68 .and terminates at an outer end 73 a short distance within the end of the assembly 52 or 53. The valve stem guide 68 itself, which helps to provide a bearing for the reciprocating action of the valve 61 or 63, extends beyond the housing 48 or 51 into the assembly 52 or 53.

Each assembly 52, 53 (see FIG. 6) may comprise a simple housing 74, fiat at each end to seat between the housing 48 or 51 and the assembly 54 or 56 and having an intumed edge 75 at the outer end. A spring seat 76 preferably surrounds the guide 68 and rests against the flat outer end 77 of the housing 48 or 51, while a spring bearing member 78 preferably surrounds and is secured to the valve stem 71 for movement with it. An opening 79 (normally plugged) enables observation of operation of the valves, or the assembly 52, 53 may be made from transparent strong plastic. Compressed between the seat 76 and the bearing member 78 are preferably two coaxial helical springs 80 and 81, to give maximum yielding pressure in a short length.

Each valve actuating assembly 54 or 56 preferably comprises a cylinder 82 (FIG. 6) fitting in the recess 57, with a piston 83 movable therein and having a stem 84 engaging the outer end 73 of the stem 71. The piston 83 is preferably urged outwardly by a spring 85 that seats against a seat member 86. The piston 83 and cylinder 82 cooperate with the casing 9 to provide a small chamber 87 to which hydraulic fluid is conducted by a conduit 90 or 112 (FIG. 1) and port 89 to actuate the piston 83 (FIG. 6) and thereby to unseat the valve head 72. The return is by the springs 80, 81 and 85. When the fluid pressure is off, as when the engine is not operating, the spring 85 urges the stem 84 of the piston 83 out beyond the end 75 of the housing 74, and entirely within the member 86 so that disassembly is simple. A set screw 88 provides a positive thrust against each seat member 86, the thrust being transmitted through the member 74 to the cage 51 (or housing 48). For disassembly, the set screw 88 is loosened.

A suitable fuel injector device 91 (FIGS. 11 and 12) is preferably provided centrally of the combustion chamber 50. In place of the fuel injector 91 a carburetor type of operation may be used with a fuel-air mixture that passes into the chamber 50, through the intake ports 62, a spark plug 97 (see FIG. then being located at about the same point as that where the fuel injector 91 is shown in FIGS. 11 and 12. When a fuel injector 91 is used, its nozzle 92 is provided with a series of coplanar holes 93 which diverge outwardly to provide a flat fan-type spray, the shape of the spray being substantially the same shape as that of the chamber 50. Being in its own end wall, the injector 91 (or spark plug 97) does not affect the space available for the valves 61 and 63 and so does not limit the size of the valves.

The intake-valve cage 51 may be joined to the exhaust-valve housing 48 by a pair of bolts 94 (FIG. 9) and provides an intake passage 95 (FIG. 6) leading to the back of the intake valves 63. The seats 65 for the intake valves 63 are driven into the exhaust-valve housing 48, and the intake-valve cage 51 seats up against the housing 48 and is provided with suitable gaskets 96 joining it to the exhaust-valve housing 48.

An important feature of the invention is that both valves 61 and 63 and the injector 91 are hydraulically operated. In connection with this, the Z-crankshaft preferably has a cylindrical portion 100 (see FIG. 1) which extends beyond the engine housing 9 and is preferably provided with an external gear 101. That gear 101 may mesh with another gear 102 held upon an auxiliary shaft 103 and provided with double the pitch diameter of the gear 101 so that (for a four-cycle engine) the shaft 103 rotates at exactly half the speed of rotation of the shaft 100. Upon this auxiliary shaft 103, which is a cam shaft, are mounted three cams 104, 105; and 106: one for the intake valve 63, one for the fuel injector 91, and one for the exhaust valve 61. If a spark plug is used instead of the fuel injector 91, there will be only two cams, one for each valve. No matter how many cylinders are used, the three cams are sufficient for a fuel-injector engine and two cams for a spark-plug engine. In two-cycle operation, the camshaft 100 rotates at the same speed as the crankshaft 10, which may even serve as the camshaft, if desired.

The firing order of a four-cycle, three-cylinder engine of this invention is one-three-two, with 240 of rotation of the crankshaft 10, or 120 rotation of the camshaft 103 between cylinders and their valves and mechanisms. For a five-cylinder engine, the firing order is one-three-five-two-four. Each cam 104, 105, 106 engages a piston type of cam follower 107, 107a, 107b which moves in a cylinder 108, 108a, 108b in a housing 110 and exerts hydraulic pressure which is transmitted through a conduit 90, 111, or 112 to a chamber such as the chamber 87, opposite the mechanism to be fired. Thus, for the intake valve 63 and the chamber 87 is connected by the conduit 90 to the master piston 107 which is actuated by the cam 104. When pressure is exerted, the piston 83 moves to the right in FIG. 6, and causes the valve 63 to move away from its seat 65. Upon release of the piston 107 by the cam 104, the spring 85 pressure forces the cam follower 107 to follow the cam 104, and the valve 63 is reseated by the springs 80 and 81. Thus, the pistons 107, 107a, and 10711 are master pistons and the pistons 83 are slave pistons.

By using this hydraulic method of valve operation many advantages are noted. For instance, on a standard Cummins sixcylinder engine, 18 cams are required, and there are also 18 lower rocker-levers, 18 upper rocker-levers, 18 adjusting screws, 18 nuts, 18 push rods, plus many more small parts, such as rocker shafts, rocker housing castings, etc. Against that, my invention employs only three cams, nine master plungers, nine plunger chambers, and nine tubes to the injectors and valves. In addition, on the prior-art engine 18 valve adjustments must be made regularly, and I8 clearances at from .012" to .015" make a lot of noise when the engine operates. In my engine, there never is any such adjustment and no such sound because there are no clearances of this type. Also, few cams on a prior-art type engine are exactly alike, nor are all the motions of all the various parts exactly the same, and the adjustments vary, all affecting the running of the engine. Such maintenance adjustments are completely eliminated in my new engine, and the number of parts, the cost, and the noise are all reduced.

As shown in FIG. 9, the structure of this engine enables a removal of the combination of the exhaust-valve housing 48, the intake-valve cage 51, and the alignment assemblies 52 and 53, and their contents, by loosening nuts 119 on studs 120 which hold the housing 48 down against the cylinder casting 11 and then simply lifting the whole together as a unit away from the other members. Thus, it is not necessary to detach the ends of the crankcase or to concern oneself with the cylinders at all in order to make this detachment. The assemblies 52 and 53 are simply taken off then. The intake-valve cage 51 then is separated from the exhaust-valve housing 48 by removing the four bolts 94 that hold them together. The valves, valve seats, etc., may then be removed for repair through the intake ports 62.

The lubrication system of the invention is important. Lubrication is always a very important factor in engine life and efficiency, but few engines have been really properly designed for maximum efficiency, which includes both oiling and cooling. Cooling is probably the more important, as important bearings, such as those for the connecting rod and piston pins, run hot, and a surplus of cool oil is the only way to carry off this heat. Another problem in industrial engines and in earthmoving engines is due to extreme angles met in hillslide operations in all olT-highways operation. Engines have been required to run with oil piled up above bearings at one end with the crank pin bearings heating oil to foam and leaking out through seals.

In my new engine, crank pin bearings are at each end of the engine and have a deep oil sump under them. By using a socalled dry sump, a scavenging pump moves the used oil (after it flows to the sump) from the sump up to an oil tank, preferably high above the sump, and the oil is then cooled. Another pump supplies, under higher pressure, filtered and cooled oil back to all bearings. The lubrication is done preferably in a dry-sump system having a pair of sumps 121 (FIGS. 1 and 7), one at each end of the engine housing 9, from which conduits 122 carry the oil to a reservoir 123 under the influence of one or more pumps 124. By having a sump 121 at each end of the housing 9, the sumps 121 are kept dry even when the engine is tilted sharply.

From the reservoir 123, where suitable cooling, de-aeration, and filtering are provided, the oil may be forced by a pump 125 through suitable conduits 126 (FIGS. and 16) to the outer crank web 18 of the torque converter 15 and is there applied to an inlet 127. A separate conduit may be used to supply oil to the torque converter 14 from the same reservoir in a symmetrical system, or the system shown in the drawing may be used. There, the inlet 127 sends the oil via a conduit 128 to a conduit 130 through the crank pin 170. In the center of the crank pin 170 (see FIGS. 15 and 7), there is a series of branch conduits 131 and 132, three conduits 131 leading to the three recesses 36 and the conduit 132 leading to a crank pin bearing 133. The conduit 130 continues through the crank pin 170 to a conduit 134 leading through the adjacent crank web 17. From there oil passes through the central conduit 25 into a conduit 134 through the other crank web 17 on the other side of the tube 20. The conduit 134 leads to another central conduit 130 through the crank pin 170 of the converter l4 and through a conduit 136 in the other crank web 18 to a rotating thrust plate 196 and through a conduit-197 to lubricate a fixed thrust bearing 144, which is located between the thrust plate 196 and a revolving thrust plate 198. Thrust plates 137 on each side of the members 16 are lubricated by grooves not shown here by oil from conduits 138 that come off from the conduit 130 (FIG. 7). The conduit 130 also helps to lubricate all the bearings 133 and thrust plate s 139. A conduit 140 in each web 17 lubricates main bearings 141. Conduits 142 in the webs l8 lubricate main bearings 143.

In the two members 16, the branches 132 lead down to lubricate the lower portions, including the bearings 133 and the guide members 28 and 29, and oil drains down to the sump 121. The conduits 131 lead into the recesses 36 where the members 37, 38 and base members 145 and 146 provide a conduit 147 leading to the end 148 of the recess 36. From there the ball 37 is provided with an angled conduit 150, the outer end or port 151 of which is alternately covered and uncovered by the ball-socket member 39. When it is covered, the oil passes no further; but when it is uncovered, oil flows into a recess 152 surrounding the ball 37 and from there into a conduit 153 of the ball-socket member 39 leading into a conduit 154 in the center of the stem portion 41. From there, the conduit 154 flows, as shown in FIG. 3, into a conduit 155 of the member 35, which leads to a conduit 156 through the ball 33 and into a chamber 157 at the'end of the piston 31 or 32. From there, oil flows by a side chamber 158 into conduits 160 through the member 35, and thence back out of the cylinder 30. Thereby the cylinder 30 and pistons 31 and 32 are lubricated, and the excess oil falls down into the engine sumps 121. As shown, the connecting rods 40 between the pistons 31, 32 and the thrust converters l4 and 15 act to control the lubrication.

The stop-off of the conduit 150, 151 (FIG. 7) by the ballsocket member 39 is quite important, for these parts function as check valves that send oil through the conduit 154 as the connecting rods 40 are out, as in FIG. 16, and open to receive another charge of oil when the connecting rods 40 are in, as in FIGS. 7 and 15. Without this check-valve action, the oil would tend to move back and forth in the conduit 154, for the oil would not get unidirectional movement, and this could actually starve the parts 33, 34, 35 in the midst of plenty. The check-valve action assures the needed single direction of movement of the oil and thereby feeds the needed oil to the parts 33, 34, and 35.

FIG. 7 shows how this invention also makes practical the machining, assembly, and operation of the crankshaft 10. Instead of trying to have a unitary crankshaft which is cylindrical throughout with converters fixed to it at an angle,'a thing which is difficult to manufacture, and instead of having an integral crankshaft machined to provide two angular portions on which to mount the converters, I provide a crankshaft 10 which is made up of several segments.

As has been seen, the'two opposite crank webs 17 are connected together by the center tubular member 20, and between each of the two outer crank webs l8 and their respective inner webs 17 is a simple cylindrical crank pin 170. The crank webs 17 and 18 are machined to give the needed angle at faces 171 and 172, and each is preferably provided with a recess 173 or 174 the same diameter as the crank pin 170, each recess 173, 174 having an end wall 175 or 176 which lies at the exact angle required; this machining is, of course, easily done on a conventional lathe. The cylindrical crank pin has its passages 130, 131, 132, and 138 drilled as shown; when it is joined to the two crank webs l7 and 18, it fills the recesses 173 and 174, and its ends 190 and 191 bear on the recessed walls and 176. Before such joining, dowel openings 177 and 178 are provided in the respective crank webs 17 and 18, and receive dowels 180 and 181. Dowel openings 182 and 183 in the cylindrical crank pin 170 receive the other ends of the dowels 180 and 181, which thus serve to align the cylindrical crank pin 170 with the webs 17 and 18, and this proper alignment is retained when the assembly is tightened by the bolts This novel crankshaft construction enables the crank webs 17 and 18 to be made from castings or forgings by relatively simple machining, which includes machined cylindrical external walls 184 and 185 which provide journals for the main bearings 141 and 143. Both ends and 191 of the crank pin 170, the inner end 192 of each crank web 17, and the outer end 193 of each crank web 18 are perpendicular to their respective cylindrical axes. The crank pin 170 is coaxial with its member 16, with a bearing 133 therebetween; so that the assembled thrust converters 14 and 15 are easily put together and on the crank pin 170 before assembling the crank pins 170 with the crank webs 17 and 18 to complete the crankshaft 10. When assembly is complete, the crank webs 17 and 18 provide the crankshaft journals in these four main engine bearings 141 and 143. The whole is an outstandingly practical and convenient system and is relatively inexpensive to manufacture.

FIG. 20 shows a modified form of crankshaft structure which may often be preferable. Here, instead of the outer crank web l8 and the crank pin 170 being separate (as in FIG. 7), they are replaced by a unitary web-pin member 195 that is machined to give the desired surfaces and bores. It is still separate from the inner crank web 17, which may remain a separate member, or the two crank webs 17 and the tube 20 may be made integral, as shown, where a large tube 230 having a central opening 231 for oil, replaces the two webs 17 and the tube 20 and the members connecting them. The tube 230 may be machined down in between the main bearings 141, if desired. A passage 232 lubricates the bearings 141, which may be integral with an outer cylindrical tubular housing 233, or may be assembled to such a housing. Similarly, other structures are suggested, such as having the outer crank web 18 as a separate member but combining into one piece the inner crank web and crank pin. The structure of FIG. 20 is preferable to this generally, and it is also generally better than splitting the thrust converters 14 and 15 and making both webs 17 and 18 integral with the crank pin 20.

Another feature of the engine of this invention is that it is particularly well adapted to employ an engine brake operating on the general principles disclosed in my US. Pat.' No. 3,220,392. For example, as shown in FIG. 17, a tappet 200, between the exhaust cam 106 and its master piston 107b, has a reduced-diameter end 201 which provides an annular space 202 adjacent the master piston 1071). (Alternatively, the end 201 may be part of the piston 10712.) I also place a control valve 203 in the conduit 111 between the master piston 107a for the injector 91 and a slave piston 204 of the injector 91. The control valve 203 has at least two positions, in one of which its passage 211 connects the master piston 107a for the injector. with the injector slave 204, and in the other of which the passage 211 connects that same piston 107a by a conduit 205 with the annular space 202. Makeup oil may be provided to each one of the hydraulic lines 111 and 205 as well as the other conduits 90 and 112, by the means shown in FIG. 17, in which a makeup oil conduit 206 or 207 leads through a check valve 208 or 209 to the conduit 205 or 111, respectively.

The engine brake operates in this invention substantially as in that of my US. Pat. No. 3,220,392, in that 1 provide for cutting off the action of the injector 91 while superimposing upon the exhaust valves 61 an extra operation, which is timed by the injector cam 105 so that the engine, instead of receiving fuel, then has its supply of fuel cut off, and instead of operating in the normal diesel fashion, operates as a brake by virtue of acting as a compressor. The valve 203 may be switched by hand by a handle 210, or it may be operated (as in my US. Pat. No 3,220,392) by a solenoid or other actuator as that is actuated by the brake pedal or accelerator pedal of a vehicle in which the engine is installed, so that when the accelerator pedal is raised a certain amount (or the brake pedal is depressed a certain amount) the valve 203 is turned and the brake action is brought into operation. When the engine is being operated as a brake, the exhaust valves 61 are open to exhaust air from the end of the compression stroke to the at mosphere, the compression stroke being used to use up the inertial driving power of the vehicle and the compressed air exhausted instead of driving the piston back down. This braking force is superimposed upon the normal operation of the exhaust valves 61 and does not otherwise interfere with them; this operation holds the exhaust valves 61 open until the exhaust-valve cam 106 comes into action approximately 60 before the bottom center. Hence, there is no conflict between the two systems. The normal cam load acts as usual on exhaust except when the braking load is relieved.

De-aeration of the oil used in makeup in the hydraulic system is important, and a de-aerator 220 for this purpose is shown in FIGS. 18 and 19. A cylindrical wall 221 connects a base plate 222 to a conical cap 223 to define a housing. A central partition 224 extends up from the base plate 222 between an inlet 225 and an outlet 226 to about the same height as the wall 221, but oil can pass over the partition 224 via the interior of the cap 223. So fresh oil containing any foam enters the inlet 225 and flows over the top edge 227 of the partition 224 and out the outlet 226 while air bubbles up to the top and flows out with some oil through an orifice 228, either to atmosphere or back to the crankcase. Oil from the outlet 226 may flow to the makeup conduits 206 and 207. Studs 229 hold the device 220 together.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. For example, the combustion chamber structure with its opposed valves and separate walls for the intake valves, the exhaust valves, and the injector or igniter, may be used with conventional cylinders with advantage. As another example, the gasket 46 may be comprised of more than one gasket member. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

1 claim:

1. An opposed piston engine of the type in which each cylinder has two identical co-axial pistons that come together at the center of the cylinder and are then separated by only a narrow clearance at the end of the compression stroke and then move apart, characterized by:

a cylinder body having adjacent said center a unitary support portion to one side of the cylinder having an axially narrow through opening leading perpendicularly into said cylinder center, said narrow clearance between said pistons at the end of said compression stroke being even less than the axial extent of said through opening;

a housing bolted to said body and comprising a unitary member providing a combustion chamber mating with said through opening and having valve openings leading into said combustion chamber from opposite sides thereof;

a single gasket means sealing between said housing and said body around said combustion chamber and constituting the only joint at said combustion chamber;

intake and exhaust valves in said valve openings; and

said combustion chamber being defined by the two unitary members, namely the support portion of said cylinder body and said housing, and said valves.

2. The engine of claim 1 wherein said combustion chamber and said through opening are long and narrow in cross-section and about the save cross-sectional area with the minor axis parallel to the axis of said cylinder and the major axis perpendicular thereto, said valve openings being in flat walls of said housing bounding the long sides of said combustion chamber, each intake valve opening facing an exhaust valve opening.

3. The engine of claim 2 having a fuel injector at the end of said combustion chamber farthest from said cylinder, said fuel injector having a nozzle with jets all in a single plane parallel to said major axis and sending out fuel in a flat fan-like spray.

4. The engine of claim 2 having igniting means in said combustion chamber at an end distant from said cylinder.

5. The engine of claim 1 wherein each said cylinder comprises a separate single integral body having adjacent said center a support portion at one side terminating in a support surface having said through opening therethrough said housing having a surface mating with the support surface of said cylinder body and having said valve openings leading into said combustion chamber from opposite sides thereof at generally flat walls along axes each generally coplanar with the axis of said cylinder;

an intake valve cage removably secured to one side of said housing and having openings aligned with the valve openings on that side; and

intake and exhaust valves in said valve openings and facing each other, each said valve being removable upon removal of said intake valve cage from said housing.

6. The engine of claim 5 wherein said combustion chamber and said through opening are long and narrow in cross-section and substantially the same cross-sectional size and shape, with the minor axis parallel to the axis of said cylinder and the major axis perpendicular thereto and said gasket is also long and narrow, said valve openings being located along the long sides of said combustion chamber where a large surface area is presented, while said gasket is relatively short and exposes a small area to said combustion chamber.

7. The engine of claim 5 having separate hydraulic means for actuating each said valve.

8. A piston engine of the type having at least one cylinder, each with two identical co-axial pistons that come together at the center of the cylinder and are then separated by only a narrow clearance at the end of the compression stroke and then move apart, and having a combustion chamber and valve box arrangement at one side of the said center, including in combinations:

each said cylinder comprising a body having first cooling passage means around a cylinder wall and having adjacent said center a mounting portion at said one side terminating in a support surface, said mounting portion having an axially narrow first opening axially wider than said clearance leading perpendicularly into said cylinder along a plane perpendicular to the axis of said cylinder, said first opening being surrounded by a shelf provided by a recess in said support surface, and second opening means separated from said first opening and leading to the interior of said first cooling passage means;

said valve box arrangement including a housing comprising a unitary member providing a combustion chamber portion mating with said first opening, a surface facing and generally mating with said support surface, second cooling passage means having third opening means mating with said second opening means, said combustion chamber having valve openings on opposite sides thereof,

which sides are generally flat and generally perpendicular to the axis of said cylinder, and an end wall at the point therein most distant from said cylinder;

first gasket means resting in said recess between said housing and said cylinder body, said gasket means encompassing said combustion chamber and closing the sole joint in said combustion chamber;

means removably securing said housing tightly to said cylinder and compressing said first gasket means;

second gasket means between said housing and said body around said second and third opening means to seal around the cooling passage joint;

valve seat bushings in said valve openings;

an intake valve cage on one side of said housing having openings aligned with some of said valve openings;

means removably securing said cage to said housing; and

intake and exhaust valves facing each other and normally seated against said seat bushings for closing said valve openings in said combustion chamber, said valves being removable upon removal of said housing from said cylinder body and said intake valve cage from said housmg.

9. A piston engine of the type having an odd-number plurality of cylinders, each with two identical co-axial pistons that come together at the center of the cylinder and are then separated by only a narrow clearance at the end of the compression stroke and then move apart, and crank means for keeping said pistons timed and for transmitting power therefrom to a crankshaft, each cylinder having a combustion chamber and valve box arrangement at one side of the said center, said combustion chamber'extending perpendicular to said cylinder and generally symmetrical to the plane passing perpendicularly through said cylinder at said center and flattened in cross-section,

each said cylinder comprising a single integral body having first cooling passage means around a cylinder wall and having adjacent said center a mounting portion at said one side terminating in an end face, said mounting portion having a long and narrow first opening wider than said clearance leading perpendicularly into said cylinder along said plane, the long side thereof being perpendicular to said cylinder, said first opening being encompassed by a recessed shelf in said end face, and second opening means separated from said first opening and leading to the interior of said first cooling passage means,

said valve box arrangement including a housing comprising a unitary member providing a long and narrow combustion chamber portion mating with said first opening, a support face generally mating with said end face, second cooling passage means having third opening means mating with said second opening means, two pairs of valve openings into said combustion chamber on opposite fiat elongated sides of said combustion chamber along axes generally parallel to the axis of said cylinder, and an end wall for said combustion chamber at the point therein most distant from said cylinder,

a first gasket on said recessed shelf between said housing and said cylinder body, encompassing said combustion chamber and closing the sole joint in said combustion chamber,

a plurality of bolts removably securing said housing tightly to said cylinder and compressing said first gasket,

a second gasket more easily compressible than and thicker than said first gasket between said housing and said body en compassing said second and third opening means and sealing between said first and second cooling passage means,

valve seat bushings in said valve openings,

an intake valve cage on one side of said housing having openings aligned with the valve openings on that side,

bolts removably securing said cage to said housing,

two intake and two exhaust valves normally seated against said seat bushings for closing said valve openings in said combustion chamber, said valves being removable upon removal of said housing from said cylinder and removal of said intake valve cage from said housing,

hydraulic actuation means for said valves, and

a camshaft driven by said crankshaft and having cams thereon for timing the actuation of said hydraulic actuation means.

10. The engine of claim 9 having fuel injector means removably mounted in said end wall for introducing fuel into said combustion chamber in a flat fan-shaped spray approximately the same shape as said chamber, and hydraulic actuation means for said fuel injector means with a timing and actuation cam therefor on said camshaft.

11. An internal combustion engine including in combination:

a pair of end members and enclosure means between said end members providing an engine casing defining an enclosure;

an odd-number plurality of cylinders in said enclosure, supported parallel to each other by said engine casing, each said cylinder having adjacent the center a portion at said one side terminating in a support surface, having a first axially narrow, radially wide opening leading perpendicularly thereinto;

two identical co-axial v pistons in each said cylinder that come together at the center of the cylinder and are then separated by only a narrow clearance, narrower than said first opening, at the end of the compression stroke and then move apart, defining between them a part of a combustion chamber;

combustion chamber and valve box means extending out from said support surface of said cylinder;

a crankshaft in said casing and supported thereby parallel to said cylinders and having a pair of thrust converter members mounted thereon, at opposite ends of said cylinders;

connecting rod means connecting each said piston to one of said thrust converter members;

said combustion chamber and valve box means comprising a housing providing a unitary axially narrow, radially wide combustion chamber portion about the same cross-sectional area as said first opening with valve openings on opposite sides thereof, said sides lying generally perpendicular to said cylinder, and joined to the part of said combustion chamber in said cylinder by said first openintake and exhaust valves in said openings facing each other; and

attachment means removably securing and sealing said housing tightly to said cylinder body.

12. The engine of claim 11 having:

an intake valve cage removably secured to one side of said housing at an inner face and having an outer face;

a pair of aligning assemblies, each having end faces, one end face of one said aligning assembly bearing against the outer face of said valve cage and one end face of the other aligning assembly bearing against a corresponding outer face of said housing, the other end faces of said aligning assemblies bearing against said casing;

said intake and exhaust valves at said combustion chamber having stems extending out into said alignment assemblies;

valve actuation means in said engine casing helping to retain said alignment assemblies in place; and

said housing, said cage, and both said alignment assemblies being removable from said cylinder as a single unit upon removal of said attachment means.

13. The engine of claim 11 wherein said crankshaft comprises a central tubular portion, an inner crank web main bearing portion on each side of said tubular portion having a cylindrical periphery co-axial with said tubular portion and providing first crankshaft journals, an outer crank web main bearing portion spaced from each said inner crank web portion and having a cylindrical periphery co-axial with said tubular portion and providing second crankshafi journals, and an inclined crank pin portion between each said inner crank web portion and its adjacent outer crank web portion, each said crank pin portion having a cylindrical outer periphery with its axis inclined to the axes of said crank web portions, each said thrust converter member being positioned on a said crank pin portion between a said outer crank web portion and a said inner crankweb portion.

14. The engine of claim 13 wherein each said crank pin portion and one said outer crank web portion are an integral piece.

15. The engine of claim 13 wherein said tubular portion and both said inner crank web portions are one integral piece.

16. The engine of claim 13 wherein said crank pin portion and each of said crank web portions are each separate pieces.

17. The engine of claim 11 wherein each said cylinder is a separate body.

18. The engine of claim 11 wherein each said connecting rod means is connected to its said piston by a ball joint and is connected to its said thrust converter member by another ball joint, said thrust converter member having projecting aligning means and said casing having a stationary guide channel guiding said aligning means.

19. The engine of claim 11 wherein said connecting rod means and said thrust converter members define between them a lubrication port and means to open said port when said pistons are close to each other and to close said port when said pistons are far apart, said connecting rod means having conduit means for conducting lubricant from said port to said piston when said port is open, and pressure means supplying lubricant under pressure to the thrust-converter side of said port. u

20. An-internal combustion engine of the type having two co-axial pistons in each cylinder thatcome together at the center of the cylinder and are then separated by only a narrow clearance at the end of the compression stroke and then move apart, defining between them a part of a combustion chamber:

two pairs of engine bearings;

a crankshaft supported by said bearings and having a central cylindrical tubular portion;

acylindrical inner crank web portion on each end of said tubular portion and co-axial therewith and constituting the journals of the crankshaft running in one said pair of engine bearings;

a cylindrical outer crank web portion facing each said inner crank web portion and co-axial therewith and spaced apart therefrom and constituting the journals of the crankshaft running in the other said pair of engine bearings;

a cylindrical crank pin portion between each inner crank web portion and its facing outer crank web portion with its axis inclined relative to said central tubular portion and to said engine bearings;

means aligning each said crank pin portion with each of its said crank web portions;

means securing each said crank pin portion to both of its said crank web portions;

a pair of thrust converter members, each said converter member having a cylindrical opening encircling a crank pin, said member thereby being positioned between a said outer crank web portion and a said inner crank web portion, said converter member extending generally normal to said crank pin;

said pair of thrust converter members having connecting rod means connecting each said piston to one of said thrust converter members;

said connecting rod means and said thrust converter members defining between them a lubrication port and means to open said port when said pistons are close to each other and to close said port when said pistons are far apart;

said connecting rod means having conduit means for conducting lubricant from said port to said piston when said port is open; and

pressure means supplying lubricant under pressure to the thrust-converter side of said port. 21. The combination of claim 0 wherein said single forced lubrication system includes pump means and main conduit means extending from one end only of said crankshaft through an outer crank web, a crank pin, an inner crank web, said tubular member, the other inner crank web, the other crank pin, and the other crank web, conduits leading from said main conduit means to the cylindrical surfaces of said crank webs and the cylindrical surfaces of said crank pins and through said thrust converter means to said lubrication ports.

22. In an internal combustion engine of the type having two coaxial pistons in each cylinder that come together at the center of the cylinder and are then separated by only a narrow clearance at the end of the compression stroke and then move apart, defining between them a part of a combustion chamber, and a crankshaft in a casing and supported thereby and having a pair of thrust converter members mounted thereon at an angle relative to the main axis of said crankshaft with connecting rod means connecting each said piston to one of said thrust converter members, the improvement wherein said connecting rod means and said thrust converter members define between them a lubrication port and means to open said port when said pistons are close to each other and to close said port when said pistons are far apart, said connecting rod means having conduit means for conducting lubricant from said port to said piston when said port is open, and pressure means supplying lubricant under pressure to the thrust-converter side of said port.

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