ENGINE WITH CRANKCASE COMPRESSION

Abstract: An engine (10) has a block with a crankcase chamber (22) and two cylinders (24, 26) extending radially from the chamber (22). A piston (56, 60) reciprocates in each cylinder (24, 26). The crankcase chamber (22) accommodates a crankshaft (64) which causes the pistons (56, 60) to move in diametrically opposite directions. At any time, both pistons (56, 60) are moving either towards top dead center or towards bottom dead center. An injector (88) is arranged to admit a fuel mixture into the crankcase chamber (22) through an inlet opening (90) whenever the two pistons (56, 60) move towards top dead center. Two transfer tubes (98, 100) extend from an outlet opening (94) in the block to the combustion chambers of the respective cylinders (24, 26). The volume of fuel mixture drawn through the inlet opening (90) when the pistons (56, 60) move towards top dead center equals the sum of the displacements of the pistons (56, 60). The greater part of this volume is forced into a combustion chamber during an intake stroke with an accompanying precompression.

Description: ENGINE WITH CRANKCASE COMPRESSION RELATED APPLICATIONS This application is based on U.S. Provisional Application No. 60/101,298, entitled "Engine with Crankcase Precompression," filed on September 22, 1998. BACKGROUND OF THE INVENTION Field of the Invention The invention relates to an engine in which fluid for generating power is compressed. Description of the Prior Art Internal combustion engines represent one class of engines which generate power from compressed fluid. In such engines of the Otto cycle type, a piston reciprocating in a cylinder produces a vacuum during part of each operating cycle. The vacuum causes a volume of air, or air and fuel , approximately equal to the displacement of the piston to be sucked into the cylinder. This volume of air, or air and fuel, is then compressed by the piston inside the cylinder and subsequently ignited. The combustion products obtained upon ignition expand and cause displacement of the piston. The piston, in turn, through a connecting rod, rotates a crankshaft or drive member which serves as a power source. Much effort has been expended in increasing the power output of internal combustion engines. This is generally accomplished with a supercharger which forces additional air into a cylinder by means of a fan or positive displacement rotors. While a supercharger is effective in increasing power output, the supercharger adds substantially to the complexity, weight and cost of the engine. Furthermore, a supercharger greatly increases the probability of detonation and pre-ignition which can destroy an engine in a short time. For this reason, supercharged engines frequently have lower reliability ratings than normally- aspirated engines. The crankshaft of the engine, which is located in a crankcase, has journals or carrying elements supported by bearing sleeves or shells. A lubrication system is provided for the engine, and a major duty of the lubrication system is to remove heat from the journals and bearing sleeves. This poses little problem in smaller engines where the journals and bearing sleeves are small and the distance from the hottest location of a journal or bearing sleeve to the relatively cool atmosphere of the crankcase is not great. However, in larger engines where the journals and bearing sleeves are relatively large, the lubrication system may be unable to remove sufficient heat from the journals and bearing sleeves. Although adequate cooling in larger engines can be achieved by replacing the bearing sleeves with roller bearings or ball bearings which are more easily cooled, weight, noise and cost would all increase. SUMMARY OF THE INVENTION It is an object of the invention to increase the power output of an engine relatively simply. Another object of the invention is to reduce the likelihood of detonation in an engine. An additional object of the invention is to enhance the cooling of the carrying and bearing elements for a drive member of an engine with little or no increase in weight, noise or cost. The preceding object, as well as others which will become apparent as the description proceeds, are achieved by the invention. One aspect of the invention resides in an engine which comprises wall means defining a first passage, a second passage, and a compartment arranged to open to each of the passages. The first passage has one first end facing the compartment and an opposite first end remote from the compartment. Similarly, the second passage has one second end facing the compartment and an opposite second end remote from the compartment. A first member is reciprocable in the first passage and a second member is reciprocable in the second passage. The engine further comprises means for admitting fluid into the compartment and means for transferring fluid from the compartment to the remote first end and the remote second end. The engine also comprises fluid flow control means arranged to establish communication between the transferring means and the remote first end while sealing the remote second end from the transferring means. The fluid flow control means is further arranged to establish communication between the transferring means and the remote second end while sealing the remote first end from the transferring means. The engine additionally comprises drive means driven by the reciprocable members. The drive means and reciprocable members are arranged such that the first and second reciprocable members concurrently move towards those ends of the respective first and second passages which face the compartment. The drive means and reciprocable members are likewise arranged so that the first and second reciprocable members concurrently move towards the remote first end and the remote second end, respectively. In the above engine, the reciprocable members move away from a compartment at the same time. This allows a quantity of fluid equal to the sum of the displacements of the reciprocable members to be drawn into the compartment. The reciprocable members subsequently move towards the compartment at the same time thereby enabling the fluid to be compressed. The fluid flow control means is preferably arranged so that, when the reciprocable members move towards the compartment, communication is established between the compartment and one of the two passages in which the reciprocable members ride. Consequently, the fluid is forced into this passage by the reciprocable members and the passage receives a volume of fluid significantly greater than the displacement of the respective reciprocable member. When the reciprocable members now move away from the compartment, the fluid previously fed into the one passage can undergo additional compression. In this manner, a supercharging effect may be obtained. The above engine permits a supercharging effect to be achieved without complex fan or rotor mechanisms. Moreover, this supercharging effect is essentially free since it makes use of the normal motions of reciprocable members in engines. Another aspect of the invention resides in an engine which comprises wall means defining at least one passage as well as a compartment arranged to open to the passage. The passage has one end facing the compartment and another end remote from the compartment. A reciprocable member is reciprocable in the passage, and a drive member in the compartment is arranged to be driven by the reciprocable member. The engine further comprises means for admitting fluid into the remote end of the passage, and fluid flow control means for regulating the admission of fluid into such end. The fluid flow control means includes a rotatable valve member, and the valve member is provided with at least one port which is arranged to receive fluid from the admitting means and to admit fluid into the remote end of the passage. The valve member has an axis of rotation and is shiftable along this axis. The engine can be provided with a port, e.g., in a head of the engine, which overlaps the port in the valve member when fluid is to be admitted into the passage containing the reciprocable member. In this condition the port in the valve member is open while the same port is closed when there is no overlap with the port in the head. By designing the valve member to be rotatable as well as shiftable axially, it becomes possible to accomplish more than simply opening and closing the port in the valve member. Thus, one of the motions can be used for this purpose while the other motion can be used to vary the amount of overlap of the port in the valve member and the port in the head. A change in the amount of overlap, in turn, permits the turbulence of the fluid to be increased or decreased. An increase in turbulence when the engine is operating under conditions favoring detonation allows the probability of this phenomenon to be reduced. An additional aspect of the invention resides in an engine which, as before, comprises wall means defining at least one passage as well as a compartment arranged to open to the passage. A reciprocable member is again reciprocable in the passage, and a drive member in the compartment is again arranged to be driven by the reciprocable member. In this aspect of the invention, the engine further comprises a bearing element for the drive means, and the bearing element is provided with at least one cooling channel which extends along a sectin of the drive means and is open to the drive means along such section. In this engine, a cooling channel in a bearing element is adjacent a drive means, e.g., a crank, supported by the bearing element. The cooling channel is thus at the hottest location of the bearing element and allows the bearing element to be efficiently cooled at this location. Moreover, cooling fluid flowing through the cooling channel can cool the adjoining section of the drive means simultaneously with the bearing element. The cooling channel allows cooling of the bearing element to be improved with little, if any, increase in the weight and cost of the engine or the noise generated by the engine. Yet another aspect of the invention resides in a method of operating an engine which comprises the step of drawing fluid into a compartment by concurrently moving each of two reciprocable members along a respective passage from a first position nearer the compartment to a second position farther away from the compartment. The method further comprises the step of compressing the fluid and introducing at least a portion thereof into one of the two passages by concurrently moving each of the reciprocable members in a direction from the respective second position towards the respective first position. The method also comprises the step of additionally compressing the portion of the fluid introduced into the one passage within such passage by moving the respective reciprocable member in a direction from the respective first position towards the respective second position. The reciprocable members preferably move in diametrically opposite directions. The method can further comprise the step of rotating a valve member to control the flow of the abovementioned portion of the fluid. The method may also include the step of driving a drive member with the reciprocable members, and the drive member can, in turn, rotate the valve member. One more aspect of the invention resides in a method of operating an engine which comprises the steps of admitting fluid into a passage, and compressing the fluid in the passage by moving a reciprocable member along the passage in a predetermined direction. This method additionally comprises the steps of moving the reciprocable member along the passage in a direction opposite to the predetermined direction following the compressing step, and controlling the flow of fluid into the passage. The controlling step includes rotating a valve member on an axis of rotation, and shifting the valve member along the axis. A further aspect of the invention resides in a method of operating an engine which comprises the steps of reciprocating a reciprocable member, and driving a drive member with the reciprocable member. The drive member has a carrying element which is received by a bearing element, and the method also comprises the step of cooling the bearing element. The cooling step includes establishing fluid flow between the carrying element and the bearing element. The method according to this aspect of the invention can further comprise the step of admitting fluid into the carrying element from a location between the bearing element and the carrying element. Additional features and advantages of the invention will be forthcoming from the following detailed description of preferred embodiments when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of an engine in accordance with the invention. FIGS. 2a-2g are somewhat schematic and simplified partly sectional elevational views of the engine of FIG. 1 showing different operating stages of the engine. FIG. 3 is a partly sectional elevational view of a valve member forming part of the engine of FIG. l. FIG. 4 is a fragmentary elevational view of a crankshaft and connecting rods forming part of the engine of FIG. 1. FIG. 5 is a fragmentary elevational view of the crankshaft of FIG. 4 illustrating additional details of the crankshaft. FIG. 6 is a fragmentary view showing the inner surface of a bearing for the crankshaft of FIG. 4. FIG. 7 is a fragmentary view showing the inner surface of a further bearing for the crankshaft of FIG. 4. FIG. 8 is a fragmentary view showing the inner surface of an additional bearing for the crankshaft of FIG. 4. FIG. 9 is similar to FIG. 5 but illustrates another embodiment of the crankshaft. FIG. 10 is a simplified fragmentary sectional view of the engine of FIG. 1 taken in a horizontal plane and showing one more bearing for the crankshaft of FIG. 4. FIG. 11 is a fragmentary partly sectional view of an engine similar to that of FIG. 1 taken in a vertical plane and illustrating a cylinder head and valve of the engine. FIG. 12 is a bottom view of the cylinder head of FIG. 11. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 and FIGS. 2a-2g, the numeral 10 identifies an engine according to the invention. The engine 10 is here an internal combustion engine but could be another type of engine which generates power using compressed fluid. The engine 10 comprises a casing or housing 12 which includes a cylinder block, a cylinder head and a crankcase and contains two identical cylinders. The engine casing 12 has a plurality of walls, including a front wall 14, a back wall 16, a top wall 18 and a bottom wall 20, which cooperate to define a crankcase chamber or compartment 22 and a pair of cylinder bores or passages 24 and 26. The crankcase chamber 22 runs between the cylinder bores 24,26 which extend away from the crankcase chamber 22 in radial direction thereof. The cylinder bores 24,26, which have a circular cross section, are located on opposite sides of the crankcase chamber 22 and run in diametrically opposite directions. The cylinder bore 24 has a longitudinal end 24a adjacent to and facing the crankcase chamber 22 and an opposite longitudinal end 24b remote from the crankcase chamber 22. Likewise, the cylinder bore 26 has a longitudinal end 26a adjacent to and facing the crankcase chamber 22 and an opposite longitudinal end 26b remote from the crankcase chamber 22. Each of the longitudinal ends 24a, 26a opens to the crankcase chamber 22 which is in permanent communication with the two cylinder bores 24,26 through such longitudinal ends 24a, 26a. The longitudinal bore end 24b remote from the crankcase chamber 22 is regulated by a valve mechanism or flow control mechanism 28. Similarly, the longitudinal bore end 26b remote from the crankcase chamber 22 is regulated by a valve mechanism or flow control mechanism 30. The valve mechanism 28 is mounted in a cylinder head 106 having a flange 106a which is attached to a non- illustrated exhaust pipe by bolts 108. In like manner, the valve mechanism 30 is mounted in a cylinder head 110 having a flange 110a which is attached to a non- illustrated exhaust pipe by bolts 112 . Preferably, each of the valve mechanisms 28,30 comprises a rotatable valve member or flow control member 32 shown in FIG. 3. Considering FIG. 3, the valve member 32 includes an elongated valve element 34 of circular cross section having a tubular intake section 36 and a tubular exhaust section 38. Both the intake section 36 and the exhaust section 38 run longitudinally of the elongated element 34, and the intake section 36 and exhaust section 38 are separated from one another by a partition or dividing wall 40 extending across the lumen of the elongated element 34. The intake section 36 has a longitudinal end 36a remote from the partition 40, and a series of receiving ports or openings 42 is provided in the longitudinal end 36a. The receiving ports 42, which serve to introduce fluid into the interior of the intake section 36, form an interrupted ring which runs circumferentially of the intake section 36. The intake section 36 is further provided with a series of discharge ports or openings 44 between the receiving ports 42 and the partition 40. The discharge ports 44, which serve to transfer fluid from the intake section 36 to the cylinder bore 24 or 26, are arranged in a row extending longitudinally of the intake section 36. The ports 42,44 constitute the only ports or openings in the intake section 36. The exhaust section 38 has a longitudinal end 38a remote from the partition 40, and a series of inlet ports or openings 46 is provided in the exhaust section 38 between the partition 40 and the longitudinal end 38a. The inlet ports 46, which serve to transfer fluid from the cylinder bore 24 or 26 to the interior of the exhaust section 38, are disposed in a row running longitudinally of the exhaust section 38. The longitudinal end 38a is open to permit the discharge of fluid from the exhaust section 38 into an exhaust system. The discharge ports 44 of the intake section 36 and the inlet ports 46 of the exhaust section 38 can be round, square, triangular or trapezoidal but preferably have an oval shape or an approximately oval shape. The discharge ports 44 are offset from the inlet ports 46 circumferentially of the elongated element 34, e.g., by about 90 degrees. The elongated valve element 34 has an additional section 48 which is fast with the longitudinal end 36a of the intake section 36. The additional section 48 is provided with an array of splines or grooves 50, and the splines 50 form a circle which runs circumferentially of the additional section 48. The splines 50 are designed to engage a drive sprocket or rotating element which functions to rotate the valve member 32, and the additional section 48 may accordingly be considered a drive section of the elongated element 34. In FIG. 3, the longitudinal end 36a and additional section 48 of the elongated valve element 34 have a larger outer diameter than the remainder of the valve element 34. The elongated valve element 34 can be one piece or an assembly. FIG. 1 shows a drive sprocket or rotating element 52 for the valve member 32 of each valve mechanism 28,30. The end of each drive section 48 remote from the respective intake section 36 is provided with a non-illustrated threaded hole arranged to receive a retaining bolt or retaining element 54 for the associated valve drive sprocket 52. Turning back to FIGS. 2a-2g, a piston or reciprocable member 56 of circular cross section rides in the cylinder bore 24. The piston 56 is movable between a position adjacent to the crankcase chamber 22 (FIG. 2a) and a position near but spaced from the valve mechanism 28 (FIG. 2b) . These two positions can respectively be referred to as bottom dead center and top dead center. The piston 56 is a close sliding fit in the cylinder bore 24 and forms a seal between the longitudinal ends 24a, 24b of the bore 24. The portion of the bore 24 on the side of the piston 56 remote from the crankcase chamber 22, together with the combustion side of the cylinder head 106, constitutes a combustion chamber. Combustion in the cylinder bore 24 can be initiated by a spark plug or ignition source 58. In the case of compression-ignition as occurs, for instance, in a diesel engine, combustion can be initiated by the injection of atomized fuel. A second piston or reciprocable member 60 of circular cross section rides in the cylinder bore 26. The piston 60, which is identical to the piston 56, is displaceable between a position adjacent to the crankcase chamber 22 (FIG. 2a) and a position near but spaced from the valve mechanism 30 (FIG. 2b). As before, these two positions can respectively be referred to as bottom dead center and top dead center. The piston 60 is a close sliding fit in the cylinder bore 26 and forms a seal between the longitudinal ends 26a, 26b of the bore 26. The portion of the bore 26 on the side of the piston 60 remote from the crankcase chamber 22, together with the combustion side of the cylinder head 110, constitutes a combustion chamber. An ignition source or spark plug 62 can be used to initiate combustion in the cylinder bore 26. However, for compression-ignition as occurs, for example, in a diesel enging, combustion can be initiated by the injection of atomized fuel. It is preferred for the engine 10 to have a highly oversquare design, that is, a large bore-to-stroke ratio. Considering FIG. 4 in conjunction with FIGS. 2a-2g, a crankshaft or drive member 64 is located in the crankcase chamber 22. The crankshaft 64 has an axis of rotation R which is perpendicular to the axes of the cylinder bores 24,26. The crankshaft 64 is provided with a crank arrangement 66 comprising two lateral cranks 68 and 70 which are spaced from one another axially of the crankshaft 64. The crank arrangement 66 further comprises a central crank 72 which is situated between the lateral cranks 68,70. The lateral crank 68 includes a spaced pair of crank arms or webs 68a and 68b which carry a crankpin or journal 68c. Similarly, the lateral crank 70 includes a spaced pair of crank arms or webs 70a and 70b which carry a crankpin or journal 70c. The crank arm 68b of the lateral crank 68 and the crank arm 70b of the lateral crank 70 also constitute respective crank arms of the central crank 72. Thus, the central crank 72 has the crank arm 68b in common with the lateral crank 68 and the crank arm 70b in common with the lateral crank 70. The crank arms 68b, 70b carry a crankpin or journal 72c of the central crank 72. The crank arms 68a, 68b,70a,70b can be circular and are perpendicular to the rotational axis R of the crankshaft 64. The crank arms 68a, 68b, 70a, 70b all have the same thickness and diameter, and the diameter of the crank arms 68a, 68b,70a,70b constitutes the maximum diameter of the crankshaft 64. The rotational axis R of the crankshaft 64 passes through the centers of the crank arms 68a, 68b, 70a, 70b. The crankpins 68c, 70c, 72c are also circular, and the axes of the crankpins 68c, 70c, 72c are parallel to the rotational axis R of the crankshaft 64. The lateral crankpins 68c,70c have the same length, and this length is one-half that of the central crankpin 72c as seen in FIGS. 2a-2g. The lateral crankpins 68c, 70c are coaxial and located to one side of the rotational axis R of the crankshaft 64. The central crankpin 72c is disposed on the diametrically opposite side of the rotational axis R, and the crankpins 68c, 70c,72c are equidistant from such axis R. A lateral connecting rod or elongated connecting member 74 is attached to the lateral crankpin 68c while a lateral connecting rod or elongated connecting member 76 is attached to the lateral crankpin 70c. Likewise, a central connecting rod or elongated connecting member 78 is attached to the central crankpin 72c. The central connecting rod 78 is affixed to the piston 56 while the lateral connecting rods 74,76 are affixed to the piston 60 at two spaced locations situated on a diameter of the piston 60. The crankpins 68c, 70c, 72c can be considered to constitute carrying elements for the respective connecting rods 74,76,78. The lateral connecting rods 74,76 have the same dimensions. As seen in FIGS. 2a-2g, the thickness of the lateral connecting rods 74,76 is one-half that of the central connecting rod 78 which otherwise has the same dimensions as the lateral connecting rods 74,76. The pistons 56,60 have the same mass while the total mass of the lateral connecting rods 74,76 equals the mass of the central connecting rod 78. Moreover, the various mounting elements employed to properly affix the lateral connecting rods 74,76 to the piston 60 and the lateral crankpins 68c,70c have the same total mass as the mounting elements employed to properly affix the central connecting rod 78 to the piston 56 and the central crankpin 72c. By virtue of this design, a uniform mass distribution exists for the pistons 56,60, the crank arrangement 66, the connecting rods 74,76,78 and the mounting elements about a first plane normal to the axis of and bisecting the crankpin 72c. In addition, a uniform mass distribution exists about a second plane perpendicular to the first plane and containing the rotational axis R. Thus, the mass on either side of the first plane is the same as is the mass on either side of the second plane. Accordingly, a dynamic mass balance is achieved and yaw vibrations are eliminated or virtually eliminated. The crankshaft 64, connecting rods 74,76,78 and mounting elements together constitute a means for reciprocating the pistons 56,60. The pistons 56,60, which are coaxial, are reciprocated in such a manner that the pistons 56,60 travel towards and reach the respective top dead centers simultaneously. Likewise, the pistons 56,60 travel towards and reach the respective bottom dead centers simultaneously. The crankcase chamber 22 is preferably designed so that the dimensions thereof are minimized. Advantageously, the dimensions of the crankcase chamber 22 equal the dimensions of the crank arrangement 66 plus just enough clearance for unimpeded rotation of the crank arrangement 66. The coaxiality of the pistons 56,60, aside from reducing or eliminating yaw vibrations, allows the smallest possible crankcase volume to be obtained. The engine 10 can operate on a mixture of fuel and air, and this mixture may be used to cool the crankpins 68c, 70c, 72c as well as journals which support the crankshaft 64 for rotation. Moreover, a small quantity of oil, e.g., 1/2 percent to 2 percent by volume, may be added to the fuel. The mixture of air, fuel and oil, which will be referred to as the fuel mixture, can additionally function to lubricate the bearings for the crankpins 68c, 70c, 72c and for the journals supporting the crankshaft 64. It is preferred for the oil incorporated in the mixture to be biodegradable. Referring to FIG. 5 together with FIG. 4, the crankshaft 64 has two journals or carrying elements 114 and 116 which support the crankshaft 64 for rotation on the rotational axis R. The journal 114 projects from the crank arm 68a to one side of the crank arrangement 66 while the journal 116 projects from the crank arm 70a to the opposite side of the crank arrangement 66. The journals 114,116 are coaxial and share the common axis R. The journal 116 is formed with an extension 118 of smaller diameter than the journal 116. The extension 118, which is coaxial with the journal 116, is provided with external threads 118a to permit connection of the crankshaft 64 to an accessory. Portions of the threads 118a have been omitted for clarity. The journal 114 can have an extension similar to that of the journal 116. A chamber or cavity 120, e.g., a plenum chamber, is located internally of the journal 116. The journal 116 has a cylindrical external bearing surface 116a, and a duct 122 extends radially from the internal chamber 120 to the bearing surface 116a. The internal chamber 120 further opens to an internally threaded axial passage 124 in the threaded extension 118. During operation, the axial passage 124 is closed by an externally threaded plug 126 which is screwed into the passage 122. The journal 114 and its extension may likewise be provided with an internal chanber and axial passage, respectively. A chamber or cavity 128 is formed internally of the 5 crankpin 68c while a chamber 130 is formed internally of the crankpin 70c. The chambers 128,130 may, for example, constitute plenum chambers. The internal chamber 128 in the crankpin 68c may project into the adjoining crank arms 68a, 68b as shown and, as also shown, the internal chamber 10 130 in the crankpin 70c may extend into the neighboring crank arms 70a, 70b. The crankpin 68c has a cylindrical external bearing surface 68d which is connected to the internal chamber 128 by a radial duct 132 while the crankpin 70c has a cylindrical external bearing surface 15 70d which is connected to the internal chamber 130 by a radial duct 134. The crankpin 72c is likewise provided with an internal chamber or cavity 136, e.g., a plenum chamber, and the 20 internal chamber 136 can project into the adjoining crank arms 68b, 70b as illustrated. The crankpin 70c has a cylindrical external bearing surface 78d, and a duct 138 extends radially from the internal chamber 136 to the bearing surface 78d. 25 The internal chambers 128,130,136 need not be located in the crankpins 68c, 70c, 72c. Instead, the portions of the connecting rods 74,76,78 adjacent to the crankpins 68c, 70c, 72c may be formed with internal chambers. 30 Each of the journals 114,116 rotates in a cylindrical bearing sleeve or bearing element having two open ends which are located opposite one another and are spaced from each other longitudinally or axially of the bearing 35 sleeve. The two open ends of the bearing sleeve can thus be considered axial or longitudinal ends of the bearing sleeve. Turning to FIG. 6 in conjunction with FIG. 5, a bearing sleeve for the journals 114,116 is identified by the numeral 140. The bearing sleeve 140 has an internal bearing surface 140a which is designed to face the external bearing surface 116a of the journal 116 or the external bearing surface of the journal 114. The internal bearing surface 140a is provided with a series of regularly spaced channels or grooves 142 which are parallel to one another. The channels 142 run axially or longitudinally of the bearing sleeve 140, that is, the channels 142 run in a direction from one longitudinal end of the bearing sleeve 140 towards the other. The internal bearing surface 140a is further provided with an annular channel or groove 144 which extends circumferentially of the bearing sleeve 140 and intersects each of the longitudinal channels 142. In FIG. 6, the annular channel 144 intersects the longitudinal channels 142 at an angle of 90 degrees. A bearing sleeve 140 is mounted on the journal 116 with the annular channel 144 passing over the radial duct 122. A second bearing sleeve 140 is mounted on the journal 114 in the same manner. Referring to FIGS. 5 and 7, each of the crankpins 68c,70c rotates in a cylindrical bearing sleeve or bearing element 146 which again has two open ends located opposite one another and spaced from each other longitudinally or axially of the bearing sleeve 146. The bearing sleeve 146, which must fit between the crank arms 68a, 68b or the crank arms 70a,70b, is shorter than the bearing sleeve 140. The bearing sleeve 146 has an internal bearing surface 146a which is designed to face the external bearing surface 68d of the crankpin 68c or the external bearing surface 70d of the crankpin 70c. The internal bearing surface 146a is provided with a series of regularly spaced channels or grooves 148 which are parallel to one another and run axially or longitudinally of the bearing sleeve 146. The internal bearing surface 146a is further provided with an annular channel or groove 150 which extends circumferentially of the bearing sleeve 146 and intersects each of the longitudinal channels 148. In FIG. 7, the annular channel 150 intersects the longitudinal channels 148 at an angle of 90 degrees. A bearing sleeve 146 is mounted on the crankpin 68c with the annular channel 150 passing over the radial duct 132. A second bearing sleeve 146 is mounted on the crankpin 70c with the annular channel 150 running over the radial duct 134. Considering FIGS. 5 and 8, the crankpin 72c rotates in a cylindrical bearing sleeve or bearing element 152 which, as before, has two open ends located opposite one another and spaced from each other longitudinally or axially of the bearing sleeve 152. The bearing sleeve 152 must fit between the crank arms 68b,70b and, since the distance between the crank arms 68b,70b is greater than the distance between the crank arms 68a, 68b or the crank arms 70a,70b, the bearing sleeve 152 can be longer than the bearing sleeve 146. The bearing sleeve 152 has an internal bearing surface 152a which is designed to face the external bearing surface 72d of the crankpin 72c. The internal bearing surface 152a is provided with a series of regularly spaced channels or grooves 154 which are parallel to one another and run axially or longitudinally of the bearing sleeve 152. The internal bearing surface 152a is further provided with an annular channel or groove 156 which extends circumferentially of the bearing sleeve 152 and intersects each of the longitudinal channels 154. In FIG. 8, the annular channel 156 intersects the longitudinal channels 154 at an angle of 90 degrees. The bearing sleeve 152 is mounted on the crankpin 72c with the annular channel 156 passing over the radial duct 138. FIG. 9, where the same numerals as in FIG, 5, plus 100, are used to identify similar elements, illustrates a crankshaft 164 which differs from the crankshaft 64 of FIG. 5. As shown in FIG. 9, the journal 214 of the crankshaft 164 has an extension 158 of smaller diameter than the journal 214. While the extension 118 of the crankshaft 64 is provided with threads 118a for connection of the crankshaft 64 to an accessory, the extension 158 of the crankshaft 164 is formed with splines 160 for this purpose. Moreover, the internal chamber 120 of the crankshaft 64, as well as the adjoining passage 124, are omitted in the crankshaft 164. Instead, the crankshaft 164 is provided with a circular chamber 162, e.g., a plenum chamber, which is disposed in the region of the junction between the journal 214 and its extension 158, i.e., at the end of the journal 214 remote from the crank arm 168a to which the journal 214 is attached. The circular chamber 162 circumscribes part of the journal 214 and part of the extension 158. The bearing sleeve for the journal 214 can resemble the bearing sleeve 140 of FIG. 6 except that the annular circumferentially extending channel 144 may be omitted. Thus, the annular channel 144 establishes a connection between the longitudinal channels 142. Since such a connection can be established in the crankshaft 164 by having the longitudinal channels open to the circular chamber 162, the annular channel 144 becomes unnecessary. The longitudinal channels in the bearing sleeve for the journal 214 can then run the length of the bearing sleeve. The journal 216 of the crankshaft 164 can have an extension with splines like the journal 214 or an extension with threads like the journal 116 of the crankshaft 64. Furthermore, the journal 216 can be provided with a circular chamber such as the chamber 162 of the journal 214 or with an internal chamber similar to the chamber 120 of the crankshaft 64. In FIG. 10, the same numerals as in FIGS. 1 and 2a-2g denote similar elements. FIG. 10 shows another bearing element 174 for the journals 114,116 of the crankshaft 64 or the journals 214,216 of the crankshaft 164. The bearing element 174 is supported in a bearing carrier 176 which, in turn, is mounted in the front wall 14 of the engine casing 12. The bearing carrier 176 extends from the outer surface of the front wall 14 to the inner surface thereof which faces the crankcase chamber 22. The bearing element 174 includes a cylindrical wall 174a which is received in the bearing carrier 176 and defines a mounting passage 178 for a journal 114,116,214,216. The mounting passage 178 has an axial or longitudinal end 178a which confronts the crankcase chamber 22 and an opposite axial or longitudinal end 178b remote from the crankcase chamber 22. At the longitudinal end 178a, the cylindrical bearing wall 174a is provided with an annular thrust flange 174b projecting radially outward from the bearing wall 174a. The bearing carrier 176 has an end surface 176a facing the crankcase chamber 22. The end surface 176a is formed with an annular cutout which receives the thrust flange 174b of the bearing element 174. The cylindrical bearing wall 174a is provided with a cylindrical cavity 180 which runs the length of the bearing wall 174a and circumscribes the mounting passage 178. The cylindrical cavity 180 intersects an annular cavity 182 which is formed in the thrust flange 174b and extends from the cylindrical bearing wall 174a to the radially outer edge of the thrust flange 174b. At this edge of the thrust flange 174b, the annular cavity 182 opens to the crankcase chamber 22. With reference again to FIG. 1, a sprocket or rotating element 80 is mounted on the crankshaft 64 externally of the engine casing 12. The crankshaft sprocket 80 is engaged by two endless transmitting members 82 and 84 which can, for example, be in the form of cog belts. The transmitting member 82 extends around and engages the valve drive sprocket 52 for the valve mechanism 28 while the transmitting member 84 extends around and engages the valve drive sprocket 52 for the valve mechanism 30. Thus, the transmitting members 82,84 function to transmit the rotational motion of the crankshaft 64 to the rotatable valve members 32 which are accordingly rotated by the crankshaft 64. A throttle body 86 is mounted on the engine casing 12, and an injector or carburetor 88 is disposed between the throttle body 86 and the casing 12. The injector or carburetor 88 is arranged to introduce fluid in the form of a mixture of air and atomized fuel and oil into the crankcase chamber 22 and constitutes a means for admitting fluid into the chamber 22. Considering FIGS. 2a-2g together with FIG. 1, the top wall 18 of the engine casing 12 is provided with an inlet opening 90 for the introduction of the fuel mixture into the crankcase chamber 22. A one-way element 92, e.g., a reed valve, controls the flow of the fuel mixture through the inlet opening 90. The bottom wall 20 of the engine casing 12 is provided with an outlet opening 94 for the evacuation of the fuel mixture from the crankcase chamber 22. The flow of the fuel mixture through the outlet opening 94 is controlled by a one-way element 96 which can again be a reed valve, for example. A transfer tube or conduit 98 leads from the outlet opening 94 to the valve mechanism 28 located at the longitudinal end 24b of the cylinder bore 24. A second transfer tube or conduit 100 leads from the outlet opening 94 to the valve mechanism 30 located at the longitudinal end 26b of the cylinder bore 26. Turning to FIG. 3 in conjunction with FIG. 1, the transfer tube 98 has a banjo-like end with an annular portion 98a. The annular tube portion 98a encircles the receiving ports 42 of the rotatable valve member 32 constituting part of the valve mechanism 28. The fuel mixture traveling through the transfer tube 98 enters the annular tube portion 98a and then flows through the receiving ports 42 into the interior of the intake section 36 of the rotatable valve member 32. The annular tube portion 98a distributes the fuel mixture to the various receiving ports 42. The annular tube portion 98a is provided with one or more flanges 102. The flange or flanges 102 allow the annular tube portion 98a to be fastened to the cylinder head 106 by one or more fastening elements 104 such as bolts. As illustrated in FIG. 1, the transfer tube 100 also has a banjo-like end with an annular portion 100a. The annular tube portion 100a circumscribes the receiving ports 42 of the rotatable valve member 32 forming part of the valve mechanism 30. The fuel mixture traveling through the transfer tube 100 enters the annular tube portion 100a and then flows through the receiving ports 42 into the interior of the intake section 36 of the rotatable valve member 32. The annular tube portion 100a distributes the fuel mixture to the various receiving ports 42. Similarly to the annular tube portion 98a of the transfer tube 98, the annular tube portion 100a of the transfer tube 100 is provided with one or more flanges for attachment of the annular tube portion 100a to the cylinder head 110. The flange or flanges of the annular tube portion 100a are not visible in FIG. 1. The crankcase chamber 22 is arranged to communicate with the injector or carburetor 88 by way of the valve 92 and with the transfer tubes 98,100 by way of the valve 96. The crankcase chamber 22 is further arranged to communicate with the portion of each cylinder bore 24,26 located on the same side of the respective piston 56,60 as the crankcase chamber 22. Otherwise, the crankcase chamber 22 is sealed. The operation of the engine 10 will be described with reference to FIGS. 2a-2g. In this description, the arrows E and I indicate only whether the fuel mixture is entering or leaving the cylinder bores 24,26. The actual directions of flow outside of the cylinder bores 24,26 will differ from the directions denoted by the arrows E and I. Considering FIG. 2a, the pistons 56,60 are just beginning to move away from bottom dead center. The valve 96 and the valve mechanism 30 are closed. On the other hand, the valve 92 has opened, and the same is true for the exhaust section 38 of the valve mechanism 28 as indicated by the arrow E. As the pistons 56,60 travel towards top dead center, a vacuum is created in the crankcase chamber 22 and the adjoining portions of the cylinder bores 24,26. A mixture of air and atomized fuel from the injector or carburetor 88 is drawn into the crankcase chamber 22 and the adjoining portions of the cylinder bores 24,26 through the inlet opening 90. The volume of fuel mixture drawn into the crankcase chamber 22 and the adjoining portions of the cylinder bores 24,26 is equal to the sum of the displacements of the pistons 56,60. When the pistons 56,60 reach top dead center, the valve 92 and the valve mechanism 28 close. In FIG. 2b, the pistons 56,60 have just begun to move away from top dead center. The valve 92 and the valve mechanism 30 are closed whereas the valve 96 and the intake section 36 of the valve mechanism 28 have opened. The arrow I denotes that the intake section 36 of the valve mechanism 28 is open. As the pistons 56,60 travel towards bottom dead center, the pistons 56,60 compress the fuel mixture previously drawn into the crankcase chamber 22 and the adjoining portions of the cylinder bores 24,26. At the same time, the pistons 56,60 force the compressed fuel mixture through the opening 94, the transfer tube 98 and the intake section 36 of the valve mechanism 28 into the longitudinal end 24b of the cylinder bore 24. The piston 56 is on an intake stroke, and the fuel mixture flowing through the longitudinal end 24b enters the portion of the cylinder bore 24 which serves as a combustion chamber. Due to unavoidable frictional losses, the volume of fuel mixture fed into the combustion chamber of the cylinder bore 24 is slightly less than the sum of the displacements of the pistons 56,60. However, this volume is significantly greater than the displacement of the piston 56 alone or the displacement of the piston 60 alone. Once the pistons 56,60 reach bottom dead center, the valve 96 and the valve mechanism 28 close. Turning to FIG. 2c, the pistons 56,60 are just beginning to move away from bottom dead center. The valve 96 and the valve mechanism 28 remain closed while the valve 92 and the exhaust section 38 of the valve mechanism 30 have opened. The opening of the exhaust section 38 of the valve mechanism 30 is indicated by the arrow E. As the pistons 56,60 move towards top dead center, a new quantity of fuel mixture equal to the sum of the displacements of the pistons 56,60 is drawn into the crankcase chamber 22 and the adjoining portions of the cylinder bores 24,26. The piston 56 is on a compression stroke and compresses the fuel mixture in the combustion chamber of the cylinder bore 24. This compression in the combustion chamber of the cylinder bore 24 constitutes an additional compression of the fuel mixture since such fuel mixture was compressed previously. When the pistons 56,60 reach top dead center, the valve 92 and the valve mechanism 30 close and the spark plug 58 fires to ignite the fuel mixture in the combustion chamber of the cylinder bore 24. Referring to FIG. 2d, the pistons 56,60 have just begun to move away from top dead center. The valve 92 and the valve mechanism 28 remain closed whereas the valve 96 and the intake section 36 of the valve mechanism 30 have opened. Opening of the intake section 36 of the valve mechanism 30 is denoted by the arrow I. The piston 56 is on a power stroke. As the pistons 56,60 travel away from top dead center, the pistons 56,60 compress the new fuel mixture in the crankcase chamber 22 and the adjoining portions of the cylinder bores 24,26. Concurrently, the pistons 56,60 force the new fuel mixture through the opening 94, the transfer tube 100, the intake section 36 of the valve mechanism 30 and the longitudinal end 26b of the cylinder bore 26. The piston 60 is on an intake stroke, and the fuel mixture flowing through the longitudinal end 26b enters the portion of the cylinder bore 26 which serves as a combustion chamber. Due to unavoidable frictional losses, the volume of fuel mixture fed into the combustion chamber of the cylinder bore 26 is slightly less than the sum of the displacements of the pistons 56,60. However, this volume is significantly greater than the displacement of the piston 56 alone or the displacement of the piston 60 alone. Once the pistons 56,60 reach bottom dead center, the valve 96 and the valve mechanism 30 close. Considering FIG. 2e, the pistons 56,60 are just beginning to move away from bottom dead center. The valve 96 and the valve mechanism 30 remain closed while the valve 92 and the exhaust section 38 of the valve mechanism 28 have opened. The arrow E indicates that the exhaust section 38 of the valve mechanism 28 is open. As the pistons 56,60 move towards top dead center, an additional quantity of fuel mixture equal to the sum of the displacements of the pistons 56,60 is drawn into the crankcase chamber 22 and the adjoining portions of the cylinder bores 24,26. The piston 56 is on an exhaust stroke and pushes the products of the earlier combustion in the combustion chamber of the cylinder bore 24 out of this combustion chamber through the exhaust section 38 of the valve mechanism 28. The piston 60, on the other hand, is on a compression stroke and compresses the fuel mixture in the combustion chamber of the cylinder bore 26. This compression in the combustion chamber of the cylinder bore 26 constitutes an additional compression of the fuel mixture since such fuel mixture was compressed previously. When the pistons 56,60 reach top dead center, the valve 92 and the valve mechanism 28 close and the spark plug 62 fires to ignite the fuel mixture in the combustion chamber of the cylinder bore 26. Turning to FIG. 2f, the pistons 56,60 have just begun to move away from top dead center. The valve 92 and the valve mechanism 30 remain closed whereas the valve 96 and the intake section 36 of the valve mechanism 28 have opened. The opening of the intake section 36 of the valve mechanism 28 is denoted by the arrow I. The piston 60 is on a power stroke. As the pistons 56,60 travel away from top dead center, the pistons 56,60 compress the fuel mixture most recently admitted into the crankcase chamber 22 and the adjoining portions of the cylinder bores 24,26. At the same time, the pistons 56,60 force this fuel mixture through the opening 94, the transfer tube 98, the intake section 38 of the valve mechanism 28 and the longitudinal end 24b of the cylinder bore 24. The piston 56 is again on an intake stroke, and the air/fuel mixture flowing through the longitudinal end 24b enters the portion of the cylinder bore 24 which serves as a combustion chamber. As before, the volume of fuel mixture introduced into the combustion chamber of the cylinder bore 24 is significantly greater than the displacement of the piston 56 alone or the displacement of the piston 60 alone. Once the pistons 56,60 reach bottom dead center, the valve 96 and the valve mechanism 28 close. Referring to FIG. 2g, the pistons 56,60 are just beginning to move away from bottom dead center. The valve 96 and the valve mechanism 28 remain closed while the valve 92 and the exhaust section 38 of the valve mechanism 30 have opened. The opening of the exhaust section 38 of the valve mechanism 30 is indicated by the arrow E. As the pistons 56,60 move towards top dead center, yet another quantity of fuel mixture equal to the sum of the displacements of the pistons 56,60 is drawn into the crankcase chamber 22 and the adjoining portions of the cylinder bores 24,26. The piston 60 is on an exhaust stroke and pushes the products of the earlier combustion in the combustion chamber of the cylinder bore 26 out of this combustion chamber through the exhaust section 38 of the valve mechanism 30. In contrast, the piston 56 is on a compression stroke and compresses the fuel mixture which has just entered the combustion chamber of the cylinder bore 24. This compression in the combustion chamber of the cylinder bore 24 constitutes an additional compression of such fuel mixture since the latter was compressed previously. When the pistons 56,60 reach top dead center, the valve 92 and the valve mechanism 30 close and the spark plug 58 fires to ignite the fuel mixture in the combustion chamber of the cylinder bore 24. The operating sequence now reverts to FIG. 2d and is repeated while the engine 10 runs. Although the pistons 56,60 move towards top dead center together and towards bottom dead center together, the piston 56 and the piston 60 are 180 crankshaft degrees out of phase. Thus, while one of the pistons 56,60 is on an intake stroke, the other is on a power stroke. Similarly, when one of the pistons 56,60 is on a compression stroke, the other of the pistons 56,60 is on an exhaust stroke. This arrangement is balanced and yields evenly spaced firing impulses 360 degrees apart. Since the volume of fuel mixture fed into the combustion chamber of the cylinder bore 24 or 26 exceeds the displacement of the respective piston 56 or 60, and since the fuel mixture is compressed during introduction into the combustion chamber and then again after introduction, a supercharging effect is obtained. This supercharging effect is achieved without a complicated fan or rotor mechanism. Furthermore, the effect is virtually free inasmuch as it is based on the actions which occur during routine operation of an engine. The supercharging effect makes it possible for the horsepower and torque of the engine 10 to be significantly increased at low cost. The horsepower and torque of the engine 10 may be 40 to 45 percent greater than the horsepower and torque without crankcase compression. The fuel mixture drawn into the crankcase chamber 22 can lubricate and cool the crankshaft bearing sleeves 140,146,162 and, in addition, can cool the undersides of the pistons 56,60. This enables temperature gradients, as well as the probability of detonation and piston failure, to be greatly reduced. Moreover, the pump, sump and lines normally required for the lubrication of crankshaft bearing elements may be eliminated. Returning to FIGS. 5-9, a charge or pulse of fresh fuel mixture is periodically admitted into the crankcase chamber 22 as the crankshaft 64 or 164 rotates. Since the fuel in each charge has just undergone atomization or evaporation, the charge is cold and can cool the entire crankcase. The charge is under pressure, and a portion of the charge flows into the longitudinal channels 142,148,154 of the respective bearing sleeves 140,146,152. In the case of the crankshaft 64, the fuel mixture flowing along the longitudinal channels 142,148,154 enters the annular channels 144,150,156 and is then forced into the internal chambers 120,128,130,138 under crankcase pressure. On the other hand, in the crankshaft 164, although the fuel mixture is introduced into the internal chambers 228,230,238 by way of the annular channels 150,156, the mixture is fed into the circular chamber 162 directly from the longitudinal channels 142. The pressurized fuel mixture in the internal chambers 120,128,130,138 of the crankshaft 64 or, alternatively, in the circular chamber 162 and internal chambers 228,230,238 of the crankshaft 164, flows out under reduced pressure across the surfaces of the bearing sleeves such as the sleeves 140,146,152. Accordingly, a pressure-driven flow of fresh and cold fuel mixture is delivered to the bearing surfaces in the crankcase chamber 22 at least once during each revolution of the crankshaft 64 or 164. If the internal chambers 120,128,130,138,228,230,238 and the circular chamber 162 should fill up with oil, they may lose their function. Depending upon the circumstances, the chambers 120,128,130,138,162,228,230,238 may be connected to the low-pressure side of the throttle body by a line or may be provided with drain passages which allow oil to drain out by centrifugal force. In normal engines, lubrication of the wrist pins does not require special attention. However, since the engine 10 of the invention is a high-performance engine, enhanced lubrication is desirable to reduce the temperature of the pins and the piston crowns. To this end, the wrist pins are hollow and have their ends plugged, e.g., with plastic buttons, so that an internal chamber or plenum chamber is formed in each pin. To avoid scoring the wrist pins, the pins are press-fit in the pistons 56,60 and rock in the bushings which support the small ends of the connecting rods 74,76,78. The bushings are provided with longitudinal channels or grooves as well as a central annular channel or groove which intersects the longitudinal channels. Fuel mixture flowing into the longitudinal channels of a bushing enters the central annular channel from where the mixture is forced into the respective wrist pin by way of a duct. Considering FIG. 10, cold fuel mixture is fed into the cylindrical cavity 180 of the bearing element 174 under pressure from at least one hole in the bearing carrier 176. The fuel mixture enters the cylindrical cavity 180 at the longitudinal end 178b of the mounting passage 178, that is, at or near the area of the cylindrical cavity 180 which is farthest from the thrust flange 174b. The fuel mixture is distributed circumferentially of the cylindrical cavity 180 and travels the length of the cylindrical bearing wall 174a to the annular cavity 182 in the thrust flange 174b. The fuel mixture then flows radially outward through the annular cavity 182 and is discharged into the crankcase chamber 22 with a reduction in pressure. Movement of the pistons 56,60 in diametrically opposite directions permits the amplitudes of the torque reaction and the exhaust pulses to be halved. Such movement also permits the vibrations due to reciprocation of the piston 56 and the vibrations due to reciprocation of the piston 60 to cancel out almost entirely. As mentioned previously, a uniform mass distribution exists for the pistons 56,60, the crank arrangement 66, the connecting rods 74,76,78 and the mounting elements for the rods 74,76,78 about a first plane normal to the axis of and bisecting the crankpin 72c. In addition, a uniform mass distribution exists about a second plane perpendicular to the first plane and containing the rotational axis R. These uniform mass distributions enable a dynamic mass balance to be achieved thereby allowing yaw and its accompanying vibrations to be entirely or almost entirely eliminated. The large bore-to-stroke ratio permits piston speed to be reduced. This, in turn, makes it possible to decrease wear and internal stresses in, and to increase the life of, the engine 10. The large bore-to-stroke ratio further allows volumetric and thermal efficiencies to be increased. Such ratio additionally makes it possible to reduce thermal gradients thereby enabling the likelihood of detonation to be decreased. The large bore-to-stroke ratio also permits the maximum connecting rod angle to be reduced. This allows the weights of the connecting rods 74,76,78, as well as the functional length of the crankshaft 64, to be decreased. In addition, side thrust and friction on the cylinder walls is reduced. Consequently, stiffness is increased and engine weight decreased. At the same time, friction and the heat generated by the same are reduced thus further decreasing the tendency for detonation. As indicated earlier, the rotatable valve member 32 may be one piece or an assembly and can be driven by a cog belt. A valve system including the rotatable valve member 32 has many advantages including several of great importance in reducing or eliminating detonation. Among the advantages of such a system are the following: 1. The rotatable valve member 32 allows temperature gradients to be reduced and hot spots to be substantially eliminated thereby reducing the likelihood of detonation. This is due to rotation of the warm exhaust section 38 of the valve member 32 to the cooler outer portion of the cylinder head during each operating cycle. 2. When the rotatable valve member is one piece, heat can flow from the warm exhaust section 38 to the relatively cold intake section 36. This enables the temperature gradient across the cylinder head and the crown of the neighboring piston 56 or 60 to be reduced thus further decreasing the likelihood of detonation. 3. The rotatable valve member 32 allows the temperature at the exhaust side of the cylinder head to be decreased because the hot exhaust gases exit through the valve member 32 rather than through a port in the actual material of the cylinder head 106 or 110. If desired, the internal surfaces of the exhaust section 38 of the valve member 32 can be coated with a refractory material to insulate the valve member 32 and the head from high heat loads. 4. The rotatable valve member 32 can be mounted so that it does not protrude into the adjoining combustion chamber (as do poppet valves) thereby allowing high compression ratios to be obtained. 5. The system is simple, reliable and self- lubricating and seldom requires adjustment. 6. The operation of the system is not greatly endangered by accidental overrevving which can quickly damage a poppet valve engine. 7. The system is quiet. 8. The system permits the use of extremely small combustion chamber volumes. This, in turn, makes it possible to achieve the high compression ratios required when alcohol and propane are to be used as fuels. 9. The rotatable valve member 32 can serve as a structural element for stiffening the cylinder head 106 or 110. 10. The rotatable valve member 32 enables the number of parts for transferring fluid from the crankcase chamber 22 to the combustion chamber in one of the cylinder bores 24 or 26 to be reduced from approximately twenty to as little as two, namely, the valve member 32 itself and the transfer tube 98 or 100. The number of parts could be greater than two if necessary or desirable, e.g., the drive section 48 of the valve member 32 could be made as a separate part. 11. The rotatable valve member 32 allows the frontal area of the cylinder head to be significantly reduce . 12. The power required to drive the rotatable valve member 32 varies directly with rpm whereas the power required to drive a poppet valve varies as the square of the rpm. In FIG. 11, the same numerals as in FIGS. 1-3, plus 300, identify similar elements. FIG. 11 shows that a transfer tube 400 may include an annular tube portion 400a and a separate conduit 400b such as a hose. The annular tube portion 400a is connected to the conduit 400b by a clamping arrangement 354. The annular tube portion 400a is formed with a flange 356. The flange 356 permits the annular tube portion 400a to be attached to the cylinder head 410 by suitable fastening elements 358, e.g., screws. FIG. 11 also shows a rotatable valve member 332 which is designed to undergo limited movement in axial or longitudinal direction thereof. The rotatable valve member 332 has an elongated valve element 334 which differs from the elongated valve element 34 of FIG. 3 in that the valve element 334 is provided with a radially outward projecting annular flange 360 in the region of the receiving ports 342. Furthermore, in the valve element 34, the additional section 48 and the longitudinal end 36a of the intake section 36 have an outer diameter greater than that of the exhaust section 38. In contrast, the exhaust section 338 of the elongated valve element 334 has the same outer diameter as the additional section 448 and the longitudinal end 336a of the intake section 336. Moreover, while the additional section 48 of the valve element 34 is splined, the additional section 448 of the valve element 334 is not. The splines 50 in the additional section 48 of the elongated valve element 34 establish a connection with the respective drive sprocket 52 which serves to rotate the rotatable valve member 32. Thus, the drive sprockets 52 are provided with splines which mesh with the splines 50 of the respective elongated valve element 34. In FIG. 11, the drive sprocket 352 is formed without splines and, instead, has a connecting portion 352a for attachment of the drive sprocket 352 to the elongated valve element 334. The connecting portion 352a projects axially outward from a toothed portion 352b which constitutes part of the drive sprocket 352 and functions to engage an endless transmitting member such as a cog belt. The elongated valve element 334 has a cylindrical wall 334a which, at the end of the additional section 448 remote from the intake section 336 of the valve element 334, has a cylindrical end face directed away from the intake section 336. The connecting portion 352a of the drive sprocket 352 is attached to this end face by fastening and adjusting elements 362, e.g., screws, passing through slotted holes in the connecting portion 352a. The fastening and adjusting elements 362 serve not only for attachment of the drive sprocket 352 to the elongated valve element 334 but also for fine adjustment of the timing of the rotatable valve member 332. A disk 364 is inserted in the end of the additional section 448 remote from the intake section 336 and closes the elongated valve element 334 at such end. The disk 364 has a thickened central portion 364a provided with a threaded opening. An externally threaded operating element 366, e.g., a button-head bolt, extends through a hole in the connecting portion 352a of the drive sprocket 352 and screws into the threaded opening of the disk 364. The rotatable valve member 332 is slidable in axial or longitudinal direction thereof relative to the cylinder head 410 as well as to the drive sprocket 352, the fastening and adjusting elements 362 and the operating element 366. In FIG. 11, the valve member 332 slides horizontally, that is, from left-to-right and right-to- left. The annular flange 360 of the elongated valve element 334 is located inside the annular tube portion 400a of the transfer tube 400 and has a major surface 360a which faces away from the cylinder head 410. The major flange surface 360a is subjected to the pressure of the fuel mixture flowing from the transfer tube 400 into the valve member 332. This pressure urges the rotatable valve member 332 towards the right as seen in FIG. 11. The annular flange 360 cooperates with the annular tube portion 400a, the cylindrical wall 334a of the elongated valve element 334 and the cylinder head 410 to define a compartment 368 for at least one spring 370, e.g., a spiral spring. The annular flange 360 has a second major surface 360b which faces away from the major flange surface 360a and confronts the compartment 368, and the spring or springs 370 bear against the second major surface 360b and against the cylinder head 410. The spring or springs 370 urge the rotatable valve member 332 to the left as seen in FIG. 11. Movement of the rotatable valve member 332 to the right is limited by the spring or springs 370 which prevent further movement when the force exerted on the major flange surface 360b by the spring or springs 370 balances the force exerted on the major flange surface 360a by the fuel mixture. On the other hand, movement of the rotatable valve member 332 to the left is limited by a stop or abutment 372 formed on the inner surface of the annular tube portion 400a of the transfer tube 400. Movement of the rotatable valve member 332 to the left ceases when the major flange surface 360a contacts the stop 372. In FIG. 11, the rotatable valve member 332 is in its leftmost position in which the major flange surface 360a bears against the stop 372. Axial or longitudinal movement of the rotatable valve member 332 can occur even if the valve member 332 is driven in rotation by meshing splines on the valve drive sprocket 352 and the additional section 448 of the elongated valve element 334. Movement of the valve member 332 under these conditions can, for instance, be accommodated by designing the valve drive sprocket 352 and the transmitting member, e.g., the cog belt, which engages the same so that the width of the valve drive sprocket 352 exceeds the width of the transmitting member by an amount equal to the desired displacement of the rotatable valve member 332. By way of example, the rotatable valve member 332 can be arranged to move axially through a distance equal or approximately equal to 0.25 inch or 6mm. This distance may correspond to 75 percent of the width of the discharge ports 344 in the elongated valve element 334. The cylinder head 410 is formed with a series of outlet ports 374 which have the same size and shape as, and are equal in number to, the discharge ports 344. The discharge ports 344 of the rotatable valve member 332 are separated from one another by webs or bridges 344a while the outlet ports 374 of the cylinder head 410 are separated from each other by webs or bridges 374a identical in size and shape, and equal in number, to the webs 344a. The webs 344a, 374a cooperate with one another to change the effective port width as the rotatable valve member 332 is shifted axially. The effective port width is the dimension of the free area, considered widthwise of the ports 344,374, which is available for flow of the fuel mixture. The rotatable valve member 332 is arranged so that the discharge ports 344 of the valve member 332 are exactly in register with the outlet ports 374 of the cylinder head 410 when the valve member 332 is in its rightmost position. This situation is depicted at A in FIG. 12 which illustrates that the webs 344a, 374a are also exactly in register. In the rightmost position of the rotatable valve member 332, the effective port width EW is a maximum and the entire width of the ports 344,374 is available for the fuel mixture to flow through. At B in FIG. 12, the rotatable valve member 332 has been shifted slightly to the left from its rightmost position. Neither the ports 344,374 nor the webs 344a, 374a are exactly in register any longer and a portion of each valve port 344 is blocked by a web 374a of the cylinder head 410. The webs 344a, 374a cooperate with one another to reduce the effective port width EW from its maximum value. At C in FIG. 12, the rotatable valve member 332 has been shifted farther to the left, i.e., has been shifted left from its position at B. The effective port width EW is accordingly reduced from that at B. The rotatable valve member 332 has assumed its leftmost position at D in FIG. 12 and the effective port width EW is a minimum. The axial shifting of the rotatable valve member 332 is intended to inhibit detonation and preignition. Detonation is a phenomenon in which the fuel mixture is too lean and ignites throughout its volume rather than having flame-front burning characteristics. The result is a sharp pressure rise which leads to high pressure loads and high heat loads. Detonation, which is generally audible as pinging, causes oil film erosion as well as the erosion of valves, piston tops and the surfaces of the combustion chambers. Detonation can also raise the temperature of spark plug points, valves and other exposed and poorly cooled elements to such a degree that one or more of these elements begins to ignite the fuel mixture earlier than normal. This condition is known as pre- ignition and causes an immediate and noticeable power loss. Pre-ignition additionally results in high pressure loads and heat loads which rapidly break piston rings, burn exhaust valves and melt piston tops thereby destroying the engine. Detonation can occur when larger unvaporized fuel droplets come out of suspension due to cold conditions and/or low velocity of the fuel mixture. Detonation can take place when an engine is warm or on start-up when an engine is cold. In a warm engine, detonation may occur at low speeds under load which is referred to as "lugging" or at low to moderate speeds when the throttle is opened suddenly thereby creating an increased demand for a normal fuel mixture. Returning to FIGS. 11 and 12, detonation can be inhibited by imparting turbulence to the fuel mixture flowing from the valve member 332 into the cylinder bore 326 and by increasing the velocity of the mixture. Axial shifting of the rotatable valve member 332, which can be carried out manually or automatically, makes it possible to induce turbulence in the fuel mixture. Assuming that the engine of the invention is running at maximum horsepower and rpm, automatic operation of the valve member 332 is as follows: At maximum horsepower and rpm, the fuel mixture entering the annular tube portion 400a of the transfer tube 400 is at a pressure sufficiently high to overcome the resistance of the spring or springs 370 acting on the annular flange 360 of the elongated valve element 334. Consequently, the rotatable valve member 332 is in its rightmost position where, as shown at A in FIG. 12, the valve ports 344 are in exact register with the head ports 374. The effective port width EW is at a maximum and the fuel mixture flowing through the ports 344,374 experiences little turbulence. However, inasmuch as the engine is hot and the fuel mixture has a high velocity, turbulence is unnecessary because fuel droplets do not tend to come out of suspension and the likelihood of detonation is low. If the operator of the engine now throttles back slightly, the velocity of the fuel mixture decreases somewhat. Accordingly, the tendency of fuel droplets to come out of suspension begins to increase as does the likelihood of detonation. The pressure of the fuel mixture in the annular tube portion 400a of the transfer tube 400 decreases slightly as the engine is throttled back and the spring or springs 370 are able to shift the rotatable valve member 332 towards the left. At B in FIG. 12, the force exerted on the annular flange 360 of the elongated valve element 334 by the spring or springs 370 equals the force exerted by the fuel mixture of reduced pressure. The effective port width EW is reduced somewhat from its maximum value and the webs 344a, 374a of the elongated valve element 334 and cylinder head 410 create small steps or discontinuities in the flow paths of the fuel mixture. Hence, a small degree of turbulence is induced in the fuel mixture passing through the ports 344,374 and the velocity of the mixture is increased somewhat. The tendency of fuel droplets to come out of suspension decreases with an accompanying a decrease in the likelihood of detonation. Should the engine be throttled back farther so that the tendency of fuel droplets to come out of suspension increases from slight to moderate, the spring or springs 370 shift the rotatable valve member 332 more to the left from the position indicated at B in FIG. 12 to that indicated at C. The spring or springs 370 can shift the rotatable valve member 332 farther leftward because the pressure of the fuel mixture undergoes an additional decrease as the engine is throttled back again. The effective port width EW is reduced from that at B and the steps or discontinuities formed by the webs 344a, 374a are enlarged. Consequently, a moderate degree of turbulence and a moderate increase in velocity are imparted to the fuel mixture traveling through the ports 344,374 to counteract the moderate tendency of fuel droplets to come out of suspension. When the engine is idling and the tendency of fuel droplets to come out of suspension is high, the spring or springs 370 urge the rotatable valve member 332 to its leftmost position. In this position, which is shown at D in FIG. 12, the effective port width EW is a minimum and the steps or discontinuities created by the webs 344a, 374a are of maximum size. As a result, the degree of turbulence induced in the fuel mixture flowing through the ports 344,374 is maximized and the velocity of the mixture is increased substantially. Detonation is inhibited even when the throttle is opened suddenly. Since the energy for moving the rotatable valve member 332 comes from the spring or springs 370 and from the pressure of the fuel mixture, the energy is essentially free. As indicated earlier, it is possible to manually move the rotatable valve member 332 axially. This can be accomplished by attaching one end of a push-pull cable, which can shift the rotatable valve member left and right, to the operating element 366. The other end of the cable can be connected to a lever which is movable by hand between "Start & Idle", "Midrange" and "Performance" settings. Under such circumstances, the spring or springs 370, the stop 372 and the annular flange 360 on the elongated valve element 334 may be eliminated. A significant advantage of an oval or approximately oval shape for the ports 344,374 resides in that duration is progressively reduced as the engine is throttled back. This is due to the fact that not only the effective port width EW but also the effective port length decreases as the rotatable valve member 332 moves to the left. The effective port length is the length of the free area, considered lengthwise of the ports 344,374, which is available for flow of the fuel mixture. A progressive reduction in duration with decreasing engine speed enables smooth running to be achieved throughout the useful rpm range of the engine. Moreover, such a progressive reduction in duration allows strong midrange performance as well as a strong steady idle to be obtained and permits the engine to "tractor" at idle and trolling speeds. It is possible to bias or angle the ports 374 of the cylinder head 410 in such a manner that the fuel mixture is caused to swirl . This further reduces the tendency of fuel droplets to come out of suspension. During automatic axial shifting of the rotatable valve member 332, there will be a slight delay in movement of the valve member 332 due to inertia. This allows the incoming fuel mixture to fill the transfer tube 400 and the intake section 336 of the rotatable valve member 332 before the valve ports 344 open thereby preventing a lean idle mixture from causing detonation when the throttle is opened suddenly. A delay can also be achieved where the rotatable valve member 332 is manually shifted in axial direction thereof by inserting a delaying device in the push-pull cable used to move the valve member 332. In a conventional engine, there is only one set of conditions where rpm, throttle position, flow rate of the fuel mixture, turbulence, torque and horsepower are optimal. The design of the rotatable valve member 332 and the mounting of the latter for axial movement allow optimal conditions to be achieved more broadly over the operating range of the engine of the invention. This is demonstrated by a very strong steady idle, high torque at low rpm and an abundance of power at high rpm. An engine without the variable port timing obtainable with the rotatable valve member 332 cannot possess such flexibility. The usable rpm range of the engine of the invention may be increased by 20 to 30 percent at a cost increase of 1 to 2 percent. The rotatable and axially shiftable valve member 332 not only allows more efficient port timing to be obtained but induces the correct amount of turbulence for each speed range thereby enabling the danger of detonation to be reduced. When the intake section 36,336 of a rotatable valve member 32,332 closes, a certain quantity of pressurized fuel mixture is trapped in the transfer tube 98,100,400. When the discharge ports 44,344 again open, the trapped fuel mixture permits earlier and heavier charging of a combustion chamber to be obtained with an accompanying increase in efficiency. In fact, charging of a combustion chamber can begin even before the start of the intake stroke. The engine in accordance with the invention makes it possible to achieve an increased ratio of horsepower to weight, an increased ratio of horsepower to unit displacement, and an increased ratio of horsepower per unit of fuel consumed. Moreover, the engine is relatively simple, lightweight and silent and has relatively few parts. In addition, the engine is capable of generating high torque and is able to run without detonation or preignition even on low-grade fuels. The engine also allows good fuel efficiency to be obtained and requires no exotic materials or processes. Further, the engine can be built in an ordinary automotive machine shop. The engine of the invention can be used for different applications. For instance, the engine can be employed in motor vehicles, pumps, generators, farm implements and manufacturing plants as well as for various military applications such as drones and unmanned surveillance craft. Various modifications are possible within the meaning and range of equivalence of the appended claims.

Claims: I CLAIM : 1. An engine comprising: wall means defining a first passage, a second passage, and a compartment arranged to open to each of said passages, said first passage having one first end facing said compartment and an opposite first end remote from said compartment, and said second passage having one second end facing said compartment and an opposite second end remote from said compartment; a first reciprocable member reciprocable in said first passage; a second reciprocable member reciprocable in said second passage; means for admitting fluid into said compartment; means for transferring fluid from said compartment to said opposite first end and said opposite second end; fluid flow control means arranged to establish communication between said transferring means and said opposite first end while sealing said opposite second end from said transferring means, said fluid flow control means also being arranged to establish communication between said transferring means and said opposite second end while sealing said opposite first end from said transferring means; and drive means driven by said first reciprocable member and said second reciprocable member, said drive means, said first reciprocable member and said second reciprocable member being arranged such that said first reciprocable member and said second reciprocable member concurrently move towards said one first end and said one second end, respectively, and such that said first reciprocable member and said second reciprocable member concurrently move towards said opposite first end and said opposite second end, respectively. 2. The engine of claim 1, wherein said first passage and said second passage extend in diametrically opposite directions. 3. The engine of claim 2, wherein said first reciprocable member and said second reciprocable member have substantially the same mass, said drive means comprising a crank arrangement rotatable on a predetermined axis, and said crank arrangement including a spaced coaxial pair of first crankpins to one side of said predetermined axis and a second crankpin located between said first crankpins to an opposite side of said predetermined axis, said crank arrangement having substantially the same mass on either side of a plane containing said predetermined axis, and said crank arrangement also having substantially the same mass on either side of a plane normal to said second crankpin, said reciprocating means further comprising a first connecting rod extending from each of said first crankpins to said first reciprocable member, and said reciprocating means additionally comprising a second connecting rod extending from said second crankpin to said second recipricable member, said second connecting rod having a mass substantially equal to the sum of the masses of said first connecting rods. 4. The engine of claim 1, wherein said transferring means comprises a first conduit extending from said compartment to said opposite first end and a second conduit extending from said compartment to said opposite second end. 5. The engine of claim 1, wherein said fluid flow control means comprises a rotatable valve member. 6. The engine of claim 5, wherein said valve member is arranged to be rotated and timed by said drive means. 7. The engine of claim 5, wherein said valve member comprises an elongated element having a first tubular section and a second tubular section, said first tubular section and said second tubular section extending longitudinally of said element and being partitioned from one another, and said first tubular section being arranged to communicate with said transferring means and being provided with a first port for admitting fluid into one of said opposite ends, said second tubular section being provided with a second port for exhausting fluid from said one opposite end. 8. The engine of claim 7, wherein said first port and said second port are offset circumferentially of said elongated element. 9. The engine of claim 7, wherein said first tubular section is provided with an additional port for receiving fluid from said transferring means. 10. The engine of claim 7, wherein said elongated element further comprises a drive section for connection to said drive means. 11. The engine of claim 7, wherein at least one of said ports is triangular, trapezoidal, oval or approximately oval. 12. The engine of claim 5, wherein said rotatable valve member has an axis of rotation and is shiftable along said axis. 13. The engine of claim 1, wherein said first passage and said second passage each comprise a cylinder bore, said first reciprocable member and said second reciprocable member each comprise a piston, said compartment comprises a crankcase chamber and said drive means comprises a crank . 14. The engine of claim 1 , wherein said drive means is provided with a chamber arranged to receive fluid from said compartment. 15. The engine of claim 14, wherein said chamber is generally annular and circumscribes a portion of said drive means. 16. The engine of claim 14, wherein said drive means comprises a journal and said chamber is located in said journal . 17. The engine of claim 1 , further comprising a bearing element for said drive means, said bearing element being provided with at least one cooling channel which extends along a section of said drive means and is open to said drive means along said section. 18. The engine of claim 17, wherein said bearing element has opposed longitudinal ends and said one cooling channel extends in a direction from one of said longitudinal ends towards the other of said longitudinal ends. 19. The engine of claim 18, wherein said one cooling channel extends circumferentially of said bearing element. 20. The engine of claim 18, wherein said bearing element is provided with a plurality of cooling channels extending in a direction from one of said longitudinal ends towards the other of said longitudinal ends, and an additional cooling channel extending circumferentially of said bearing element and intersecting said channels of said plurality. 21. The engine of claim 17, wherein said drive means is provided with a chamber which opens to said one cooling channel . 22. An engine comprising: wall means defining at least one passage, and a compartment arranged to open to said one passage, said one passage having one end facing said compartment and another end remote from said compartment; a reciprocable member reciprocable in said one passage; a drive member in said compartment arranged to be driven by said reciprocable member; means for admitting fluid into said other end; and fluid flow control means for regulating the admission of fluid into said other end, said fluid flow control means including a rotatable valve member, and said valve member being provided with at least one port which is arranged to receive fluid from said admitting means and to admit fluid into said other end, said valve member having an axis of rotation and being shiftable along said axis. 23. An engine comprising: wall means defining at least one passage, and a compartment arranged to open to said one passage; a reciprocable member reciprocable in said one passage; a drive member in said compartment arranged to be driven by said reciprocable member; and a bearing element for said drive means, said bearing element being provided with at least one cooling channel which extends along a section of said drive means and is open to said drive means along said section. 24. The engine of claim 23, wherein said drive means is provided with a chamber which opens to said one cooling channel . 25. The engine of claim 23, wherein said bearing element has opposed longitudinal ends and is provided with a plurality of cooling channels extending in a direction from one of said longitudinal ends towards the other of said longitudinal ends, said bearing element further being provided with an additional cooling channel extending circumferentially of said bearing element and intersecting said channels of said plurality. 26. A method of operating an engine comprising the steps of: drawing fluid into a compartment by concurrently moving each of two reciprocable members along a respective passage from a first position nearer said compartment to a second position farther away from said compartment; compressing said fluid and introducing at least a portion thereof into one of said passages by concurrently moving each of said reciprocable members in a direction from the respective second position towards the respective first position; and additionally compressing said portion of said fluid in said one passage by moving the respective reciprocable member in a direction from the respective first position towards the respective second position. 27. The method of claim 26, wherein said reciprocable members move in diametrically opposite directions. 28. The method of claim 26, further comprising the step of rotating a valve member to control the flow of said portion of said fluid. 29. The method of claim 28, further comprising the step of driving a drive member with said reciprocable members, said drive member being arranged to rotate said valve member. 30. The method of claim 28, wherein said valve member comprises an elongated element having a first tubular section and a second tubular section, said first tubular section and said second tubular section extending longitudinally of said elongated element and being partitioned from one another, and said first tubular section being arranged to receive fluid from said compartment and being provided with a first port for admitting fluid into said one passage, said second tubular section being provided with a second port for exhausting fluid from said one passage. 31. The method of claim 30, wherein said first port and said second port are offset circumferentially of said elongated element. 32. The method of claim 30, wherein said first tubular section is provided with an additional port for receiving fluid from said compartment. 33. The method of claim 30, further comprising the step of driving a drive member with said reciprocable members, said elongated element further comprising a drive section for connection to said drive member. 34. The method of claim 30, wherein at least one of said ports is triangular, trapezoidal, oval or approximately oval. 35. The method of claim 28, wherein said valve member has an axis of rotation; and further comprising the step of shifting said valve member along said axis. 36. The method of claim 26 for use where said reciprocable members drive a drive member having a carrying element which is received by a bearing element, further comprising the step of cooling said bearing element, the cooling step including establishing fluid flow between said bearing element and said carrying element. 37. The method of claim 36, further comprising the step of admitting fluid into said carrying element from a location between said bearing element and said carrying element. 38. A method of operating an engine comprising the steps of: admitting fluid into a passage; compressing said fluid in said passage by moving a reciprocable member along said passage in a predetermined direction; moving said reciprocable member along said passage in a direction opposite to said predetermined direction following the compressing step; and controlling the flow of said fluid into said passage, the controlling step including rotating a valve member on an axis of rotation, and shifting said valve member along said axis. 39. A method of operating an engine comprising the steps of: reciprocating a reciprocable member; driving a drive member with said reciprocable member, said drive member having a carrying element which is received by a bearing element; and cooling said bearing element, the cooling step including establishing fluid flow between said carrying element and said bearing element. 40. The method of claim 39, further comprising the step of admitting fluid into said carrying element from a location between said bearing element and said carrying element.

Inventors: LYONS JAMES D, LYONS, JAMES, D.
Applicants: DUNLYON R & D INC, LYONS JAMES D, DUNLYON R & D, INC., LYONS, JAMES, D.
Application year: 1999
Main classification: F02B
IPC codes: F01L7, F01M1, F01M3, F02B29, F02B33, F02B67, F02B75, F02F7