Abstract: An exhaust gas heating unit for an exhaust system of an internal combustion engine includes a jacket heating conductor element (12) with a jacket (16) and with an electrical heating conductor (14). The electrical heating conductor (14) extends in the jacket (16) and is surrounded by insulating material (18). A heat transfer surface formation (20) is arranged on an outer side of the jacket (16) and is in heat transfer contact with same.

Abstract: An internal combustion engine includes one or more unopposed cylinder units where each cylinder unit drives the crankshaft via a yoke assembly rather than a conventional connecting rod. The yoke assembly is formed by a connecting rod assembly that can have an upper portion having a connecting member connected to the piston, and a lower portion. The connecting rod assembly moves exclusively along the bore axis of the cylinder, with no side to side motion. The connecting rod assembly also defines a transverse slot in the yoke portion in which a connecting rod bearing housing reciprocates with motion of a connecting rod journal on the crankshaft within the transverse slot. Since the motion of the connecting rod is linear, and the connecting rod bearing housing moves circularly, there are no secondary forces resulting in an inline engine using the unopposed cylinder unit configuration.

Abstract: A method and apparatus for pumping an intake charge into an engine is disclosed herein. The fuel-powered engine utilizes a barrier between an intake manifold and a crankcase of the engine to substantially protect the intake charge from contamination by engine crankcase oil, while using the natural pumping action of a reciprocating engine piston to pump the intake charge into the combustion chamber.

Abstract: A four-stroke internal combustion engine includes a first intake manifold in communication with an intake port of a cylinder. A crankshaft chamber is in communication with a cylinder bore of the cylinder and includes an inlet port adjacent the cylinder bore. A second intake manifold is in communication with the crankshaft chamber for supplying air or gas into the cylinder bore via the inlet port during a second stage of an intake stroke of a piston. An exhaust port of the cylinder is opened during a second stage of a power stroke to perform a first-stage discharge of exhaust gas. Air or gas is supplied into the cylinder bore via the inlet port during a third stage of the power stroke to perform a second-stage discharge of the exhaust gas. Exhaust gas not discharged during the third stage of the power stroke is discharged during an exhaust stroke.

Abstract: A four-stroke reciprocating piston internal combustion engine with an intake valve an exhaust valve and a valve drive assembly (18) driven by the crankshaft (4) for actuating the intake valve (8) and the exhaust valve (10) A mixture-preparation device (15) supplies an air/fuel-lubricant mixture to the crankcase, which together with the piston functions as a pump for the mixture charge. A valve drive assembly housing (19, 20, 21, 22) comprising one or more sections (19, 20, 21, 22) and the intake channel (16) is supplied with a connecting duct (17) communicating with the crankcase volume (12) either by being connected to the crankcase or the cylinder, or by being connected to the valve drive assembly housing (19, 20, 21, 22), which communicates with the crankcase volume (12), and the communication from the intake channel (16) to the crankcase volume is arranged through at least one valve.

Abstract: A four-stroke engine with intake air compression chamber. The intake air compression chamber has a pressure responsive displaceable member therein to compress inlet air passively in response to differential pressure between a sealed crankcase and air in the inlet side of the inlet air compression chamber. The displaceable member is substantially impervious to air, oil, and fuel. When the piston moves away from the intake air compression chamber, decreasing pressure draws the displaceable member toward the crankcase, and the movement of the displaceable member draws into the intake side of the inlet air compression chamber through a one way inlet valve. When the piston moves toward the inlet air compression chamber, fluidwise, compressed gas in the crankcase causes increased pressure on the displaceable member, compressing the inlet air, and directing compressed inlet air out through a one-way outlet valve.

Abstract: To provide a four-cycle combustion engine wherein the air-fuel mixture can be smoothly passed at all times by the utilization of the reciprocating motion of the piston to effectively lubricate the valve operating mechanism and the cranking mechanism and also to allow the air-fuel mixture to be supplied into the combustion chamber with a high suction efficiency. By utilization of the reciprocating motion of the piston (9), a portion of the air-fuel mixture (M) fed from the intake passage (33) is circulated through a circulating passage made up of the valve chamber (18), the first passage (24), the crankcase chamber (7) and the second passage (41).

Abstract: A four-stroke internal combustion engine is described, with at least one cylinder(9), a crankcase (3) which forms a crankcase pump and is connected via a valve (15, 18) each to an air manifold (16) for fresh air on the one hand and to an intake manifold (17) connecting the crankcase (3) with an intake port (11) of the cylinder (9) on the other hand, and with a reservoir (25) for lubricating oil arranged on a conveying device (26) for lubricating oil, with an oil circulation comprising the crankcase (3) as well as an oil separator (19) provided in the intake manifold (17) and with a device (23) for injecting fuel into the intake manifold (17) or into the combustion chamber (29) of the cylinder (9). In order to provide advantageous constructional conditions it is proposed that the conveying device (26) connected to the reservoir (25) comprises a duct (27) for injecting lubricating oil into the crankcase (3) and that the intake manifold leads to the oil separator (19) by circumventing the reservoir (25).

Abstract: A crankcase scavenged and lubricated four-stroke engine (1) comprising especially: a mixture-preparation device (15) for supplying an air-fuel-lubricant mixture; an intake channel (16) connecting to the crankcase or cylinder to supply at least air (13) to the crankcase volume (12); an overflow channel (17) connecting to the crankcase or cylinder and to the intake opening (7) with intake valve (8) to supply to the intake at least air and lubricant from the crankcase volume; a valve drive assembly (18) driven by a crankshaft (4) for actuating the intake valve (8) and the exhaust valve (10); a valve drive assembly housing (19, 20, 21, 21?, 22) comprising one or more sections (19, 20, 21, 21?, 22) which is/are separate from the crankcase but in communication exclusively with the crankcase volume via at least one small size passage (23, 24, 25, 26, 27), and each section (19, 20, 21, 21?, 22) of the valve drive assembly housing has a lowest part situated closer to the combustion chamber, than the lowest part of the

Abstract: Disclosed in the field of the four-cycle reciprocating piston internal combustion engine is an invention for a rotary ported intake and exhaust system and super-atmospherically charged on demand engine. This invention replaces the inefficient reciprocating valve system with a friction free rotating shaft with ports and passageways to produce the four cycles of the engine. It also replaces the accessory externally mounted compressors now used to super charge the engine by the use of two cylinders sharing the same minimum volume totally closed crankcase. As both pistons travel upward, they draw in air or air/fuel or that amount desired through a throttle body into the crankcase. As they travel downward, that cylinder on its intake cycle draws in air/fuel while the volume in the crankcase is compressed. Prior to the completion of the intake cycle, the crankcase pressure is released into that cylinder on its intake cycle super-atmospherically charging it. These cycles are then repeated for the other cylinder.

Abstract: An internal boost system integrated to an engine is provided which includes a blanking plate; a plenum chamber disposed within the oil sump having an exit flange disposed through a side of the oil sump; at least one one-way valve disposed through the blanking plate adapted to allow compressed air flow into the plenum chamber; a plurality of one-way valves disposed through the lower-end of the engine to allow fresh air to be drawn internally into the engine; a fresh air manifold in communication with the plurality of one-way valves disposed through the lower-end of the engine; and an internal boost supply pipe in communication with the plenum chamber exit flange and an air intake manifold of the engine.

Abstract: An engine is cranked by a motor generator at a start time of the engine. An engine ECU opens an intake valve or an exhaust valve during a compression stroke using a valve control mechanism during a period from when cranking is started until when a predetermined crank angle position (detected by a crank angle sensor) is reached, thereby reducing a compression workload.

Abstract: A four-cycle engine wherein a fuel-air-oil mixture is compressed in a crank case chamber and directed therefrom along a pathway to a combustion chamber. The pathway contains actuating mechanism for actuating the fuel intake valve leading to the combustion chamber. The pathway is restricted in volume as permitted by the actuating mechanism, preferable to a range of two to four times the piston displacement.

Abstract: A four-cycle engine fueled by a mixture of fuel and lubricant and including valve actuation mechanism contained in the path of the fuel flow. A component of the mechanism including a rotating gear having a gear shaft journalled between wall portions of the engine whereat the wall portions define in part the flow path of the fuel. Through holes provided in the walls to direct fuel-lubricant to the shaft ends journalled in the wall portions for lubrication of the said shaft ends.

Abstract: An internal combustion engine is provided wherein the crankcase is sealed from the oil pan to provide an airtight compression chamber wherein the air is compressed by action of the pistons. Air is withdrawn from the atmosphere through one-way valves on the engine block. The compressed air is then passed from the compression chamber into, optionally, a compressed air storage means where it is regulated through a valve for mixture with the air-fuel mixture from the carbureting means, thereby providing a boost in the air-fuel charge entering the combustion chambers. Lubricating modifications are also provided to lubricate the crankshaft and camshaft bearings located within the compression chamber.

Abstract: A valve assembly and method for controlling flow of gases through a passage between an engine crankcase and an engine intake manifold is provided. The method includes decreasing a flow of gases through the passage between the crankcase and the intake manifold when a temperature of the gases is greater than a predetermined temperature.

Abstract: An internal combustion engine includes at least one rotating, oscillating or reciprocating piston (20, 21) in a cylinder (11, 12). Each piston (20, 21) defines with the cylinder (11, 12) a combustion chamber (35). Each combustion chamber (35) has at least one inlet valve (36) and one exhaust valve (37), and a mechanism (40) to periodically open the inlet and exhaust valves. The valves are closed by a gas spring (80, 82) having a closing force proportional to the speed of the engine.

Abstract: An internal combustion engine comprising at least one pair of pistons (20, 21) rotating, oscillating or reciprocating in cylinder assemblies (11, 12) joined by a crankcase (13), each piston (20, 21) being driven by a crankshaft housed in the crankcase (13), the crankcase (13) including an inlet port (63) for entry of an air fuel mixture and an outlet port (65) for transfer of compressed air fuel mixture, each cylinder (11, 12) having a combustion chamber (35) and at least one inlet (36) and at least one exhaust (36) valve port communicating with the combustion chamber (35), the inlet valve port (36) being in communication with the crankcase (13) via the crankcase outlet port (65) whereby the engine is adapted to run on a four stroke cycle with the underside of the piston (20, 21) pressurising the air fuel mixture in the crankcase (13) and causing transfer of the pressurised air fuel mixture to the combustion chamber (35) via the crankcase outlet port (65) and inlet valve port (36).

Abstract: In order to create a compact four-cycle internal combustion engine with mixture lubrication comprising a cylinder which is closed on top by a cylinder head and which changes below into a crankcase, in the cylinder a piston moving up and down, in the cylinder head an intake port with an admission valve and an exhaust conduit with an exhaust valve, a carburetor for forming an oil-fuel-air mixture lubricating the engine, as well as means by which a mixture is transported within each engine cycle from the carburetor into the crank chamber closed by the crankcase and from the crank chamber into the intake port, engine which is constructed in a simple way and which is characterized by a good charging behavior, it is proposed that the carburetor is connected outside the crank chamber with the intake port.

Abstract: A crankcase inducted self-supercharging four-cycle internal combustion engine that uses cylinder pairs as an induction pump. The cylinder pairs are arranged in a 360-degree crank throw so that both pistons rise and fall together. The system uses two valves and two tubes force air into the crankcase and then into the cylinders in a supercharged mode. It can also operate with both valves closed in a naturally aspirated mode. In this case, air is directed directly into the cylinder through an intake manifold.

Abstract: An internal combustion engine comprising at least one pair of pistons (20, 21) rotating, oscillating or reciprocating in cylinder assemblies (11, 12) joined by a crankcase (13), each piston (20, 21) being driven by a crankshaft housed in the crankcase (13), the crankcase (13) including an inlet port (63) for entry of an air fuel mixture and an outlet port (65) for transfer of compressed air fuel mixture, each cylinder (11, 12) having a combustion chamber (35) and at least one inlet (36) and at least one exhaust (36) valve port communicating with the combustion chamber (35), the inlet valve port (36) being in communication with the crankcase (13) via the crankcase outlet port (65) whereby the engine is adapted to run on a four stroke cycle with the underside of the piston (20, 21) pressurising the air fuel mixture in the crankcase (13) and causing transfer of the pressurised air fuel mixture to the combustion chamber (35) via the crankcase outlet port (65) and inlet valve port (36).

Abstract: An internal combustion engine comprising at least one rotating, oscillating or reciprocating piston (20, 21) in a cylinder (11, 12), each piston (20, 21) defining with the cylinder (11, 12) a combustion chamber (35), each combustion chamber (35) having at least one inlet valve (36) and one exhaust valve (37), and means (40) to periodically open the inlet and exhaust valves, characterised in that the valves are closed by a gas spring (80, 82) having a closing force proportional to the speed of the engine.

Abstract: A four-cycle engine wherein a fuel-air-oil mixture is compressed in a crank case chamber and directed therefrom along a pathway to a combustion chamber. The pathway contains actuating mechanism for actuating the fuel intake valve leading to the combustion chamber. The pathway is restricted in volume as permitted by the actuating mechanism, preferable to a range of two to four times the piston displacement.

Abstract: A four-cycle engine fueled by a mixture of fuel and lubricant and including valve actuation mechanism contained in the path of the fuel flow. A component of the mechanism including a rotating gear having a gear shaft journalled between wall portions of the engine whereat the wall portions define in part the flow path of the fuel. Through holes provided in the walls to direct fuel-lubricant to the shaft ends journalled in the wall portions for lubrication of said shaft ends.

Abstract: A four-stroke engine constructed using a gear with a port synchronized to the crankshaft by a power gear, and channels to direct the intake gases from the crankshaft housing into the combustion cylinder and to direct the exhaust gases out of the combustion cylinder into the atmosphere.

Abstract: A crankcase inducted self-supercharging four-cycle internal combustion engine that uses cylinder pairs as an induction pump. The cylinder pairs are arranged in a 360-degree crank throw so that both pistons rise and fall together. The cylinders are synchronized so that when one cylinder is on the intake stroke, the other is on the power stroke. A two-cycle reed valve is installed on a crankcase inlet port to draw air into the crankcase on the upstroke of the pistons. Since both pistons rise and fall together, each upstroke draws a volume of air equal to the volume of two pistons into the crankcase. When both pistons are on the down stroke, this air is compressed and, then moved into a manifold connecting the crankcase to the inlet valves of the cylinders. Thus, it is possible to double the air available for each cylinder without using storage tanks or other devices.

Abstract: An intake passage device is provided for an internal combustion engine having carburetor communicated with a connecting projection of an intake port of a cylinder of the engine, wherein the diameter of the connecting projection becomes smaller toward the inside of the intake port. A connecting pipe is provided for communicating the carburetor with the intake port. An inner end of the connecting pipe is engaged in the connecting projection. There is formed a plurality of one communication passages formed in the connecting pipe for communicating an inside of the connecting pipe with a space between an inside wall of the connecting projection and an outside wall of the connecting pipe.

Abstract: A four-cycle engine in which a mixed gas of a fuel and air containing a lubricating oil is transferred from a carburetor to a cylinder or a crank chamber, the gas is pushed out in the stage of descending the piston to the passage on the reverse side, transferred into a rocker arm chamber including an intake valve at the top of the cylinder via a passage including a valve gear mechanism, and it is directed to the cylinder in the intake stage, whereby the engine is lubricated by the lubricating oil. The engine has no oil pan and can be run at any inclination angle (360.degree.). Also disclosed is that it is also possible for the four-cycle engine to provide a diverged second passage extending to the crank room, to provide a lead valve on a portion of the second the passage, to provide a diverged third passage extending to the lower end of the crank chamber, to provide a lead valve or rotary valve, and to provide a fourth and/or fifth passage(s) to circulate the mixed gas.

Abstract: A device for increasing crankcase compression in an internal combustion engine. The device includes a holder having an annular peripheral wall joined to an end wall. The holder is mounted on a crankshaft of the engine, between a main bearing and a crank portion with a counterweight. The crankshaft extends through the end wall and is surrounded by the peripheral wall. Lightweight filling bodies are disposed in the holder.

Abstract: Several embodiments of crankcase compression supercharged four-cycle internal combustion engines. Supercharger pressure is controlled by bypassing pressurized gases from the crankcase back to the crankcase downstream of a check valve that permits flow into the crankcase so as to avoid the escape of pressurized gases to the atmosphere and to reduce pumping losses and improve performance. Various positioning of the components is illustrated. Also, an improved and simplified internal EGR system is employed.

Abstract: The present invention provides a small and light four-stroke cycle internal combustion engine applicable to a compact power working machine. A cylinder head is provided with an ignition plug and an exhaust port with an exhaust valve. A crankcase is fixed to the bottom of a cylinder block are to form a closed crank chamber. On the cylinder block formed are a first port and a second port which are open to a combustion chamber and are opened and closed by a piston, with the second port being communicated with the crank chamber through a communicating passage, the first port being connected to a carburetor, and an air-fuel mixture mixed with lubricating oil being supplied from the carburetor through this first port to the crank chamber.

Abstract: A multi-cylinder engine of a crankcase scavenging type suitable for use in watercraft. The engine has a very compact arrangement so that it can be used in either an outboard motor or as the prime mover for a watercraft such as a personal watercraft, to embodiments of which are illustrated.

Abstract: A watercraft is propelled by an outboard motor having a water propulsion device powered by a multi-cylinder engine of a crankcase compression type, the engine positioned within a cowling of the motor. The engine has a very compact V type arrangement. The intake system for admitting the charge to the crankcase chambers and the exhaust manifold are positioned around the outside of the engine opposite its valley. A compressor delivery to the cylinder head intake ports is positioned within the valley. The engine includes at least one crankshaft which drives a drive shaft of the water propulsion device of the motor.

Abstract: A number of embodiments of vehicles such as scooters that are powered a compact, high performance, four-cycle crankcase compression supercharged internal combustion engine. The engine is provided with two throttle valves, one on the intake side and one on the compressor side, that are operated simultaneously and in the same direction under at least some conditions so as to improve throttle response. In addition, an arrangement is provided for limiting the maximum pressure in the compressor side under low throttle and low load conditions. This improves performance and ensures against seal degradation in the lubricating system.

Abstract: A water vehicle having a hull defining an engine compartment and propelled by a water propulsion device powered by a multi-cylinder engine of a crankcase compression type positioned within the engine compartment is disclosed. The engine has a very compact "V" type arrangement. The intake system for admitting the charge to the crankcase chambers and the exhaust manifold is located in the valley between the cylinder banks. The compressor delivery to the cylinder head intake ports is on the outside of the engine. Crankshafts corresponding to each bank are maintained in synchronous rotation, with one of the crankshafts arranged to drive the water propulsion device of the water vehicle.

Abstract: A multi-cylinder engine of a crankcase compression type shown for use in an outboard motor. The engine has a very compact V type arrangement. The intake system for admitting the charge to the crankcase chambers and the exhaust manifold is located in the valley between the cylinder banks. The compressor delivery to the cylinder head intake ports is on the outside of the engine.

Abstract: Disclosed herein is a four-stroke internal combustion engine comprising a common crankcase, a crankshaft extending in the crankcase, first and second cylinders respectively extending from the common crankcase in acute angular relation to each other and respectively including first and second cylinder walls respectively including first and second exhaust gas discharge ports, a passage connecting the first and second exhaust gas discharge ports, first and second pistons respectively located in the first and second cylinders and respectively connected to the crankshaft for reciprocating movement toward and away from the crankshaft and between top dead center and bottom dead center positions, first and second cylinder heads respectively connected to the first and second cylinders, respectively partially defining first and second combustion chambers, and respectively including first and second mixture inlet passages respectively communicating with the first and second combustion chambers, first and second exhaust

Abstract: A four-cycle internal combustion engine wherein the piston connecting rod crankshaft and crankcase chamber are formed so that the crankcase chamber acts as compressor. An induction system supplies atmospheric air to the crankcase chamber and a pressure conduit supplies air from the crankcase chamber to the engine intake valve. A plenum chamber is disposed within this pressure conduit and pressure control is possible by bypassing air form the plenum chamber to the atmospheric air inlet. A throttle valve is positioned downstream of the plenum chamber so as to improve engine braking and charge forming systems are disclosed that permit a compact assembly and good response under all engine running conditions.

Abstract: Disclosed herein is an internal combustion engine comprising a crankcase assembly including a crankcase member including a crankcase cover mounting surface, and a cylinder assembly mounting surface including therein an opening, and a cylinder block fabricately separately from the crankcase assembly and including a crankcase member surface fixed to the cylinder assembly mounting surface, and a cylinder extending from the crankcase member mounting surface and communicating with the opening in the cylinder assembly mounting surface.

Abstract: A four-stroke engine comprising an engine frame including a block and a head, the block forming at least one cylinder and a crankcase. A piston is mounted for reciprocation in the cylinder, and a crank and connecting rod are mounted in the crankcase and connected to the piston. The crankcase includes a fuel inlet port and an outlet port, and a duct connects the outlet port to an intake passage in the head. The inlet port is connected to a supply of a combustible mixture comprising fuel, lubricating oil and air. During engine operation, the mixture flows through the crankcase, the duct, and the air intake passage to the cylinder. Valves and valve actuating mechanisms control the flow of the mixture to the cylinder and the flow of exhaust from the cylinder. The oil in the mixture lubricates the engine parts in the crankcase, the valves and the valve actuating mechanisms. The duct preferably forms a plenum or surge tank containing the mixture under pressure.

Abstract: Disclosed herein is a four-stroke internal combustion engine including a cylinder, a device for feeding fuel to the cylinder, a sealed crankcase chamber associated with the cylinder, a piston reciprocally movable in the cylinder and relative to the crankcase chamber to effect alternation of the pressure therein in response to piston reciprocation, an oil sump adapted to contain lubricating oil, a conduit system for recirculating oil from the sump to the crankcase chamber and from the crankcase chamber to the sump in response to alternation of the pressure in said crankcase chamber, an oil pump communicable with the oil sump and with the fuel feeding means, and a conduit operably connected to the oil pump and to the crankcase chamber so as to effect delivery of oil from the sump to the fuel feeding device in response to alternation of the pressure in the crankcase chamber.

Abstract: Two embodiments of reciprocating machines such as four cycle, internal combustion engines wherein the piston, connecting rod, crankshaft and crankcase are interrelated in such a way so as to function as a positive displacement compressor. The connecting rod serves as a valving element for the intake passage to the crankcase chamber and in one embodiment, the crankshaft functions as the valving member for the discharge passage from the crankcase chamber. An embodiment that permits pressure control by bypassing the compressed charge back to the intake passage is also described.

Abstract: This invention has an object to provide a fuel pressurizing apparatus which is light, compact, durable and inexpensive whereby a working machine can be operated even on a slope without difficulty. In order to achieve this object, a pressure adjusting chamber is formed in a portion of a passage in a breather device of an engine, and a pipe conduit is provided to communicate the pressure adjusting chamber with a fuel tank. A check valve which does not allow fuel from the fuel tank to pass is provided in a portion of this pipe conduit. A vent hole which is constantly open is provided in the fuel tank, and a cross-sectional area of the vent hole is set to maintain balance of a pressure from the pressure adjusting chamber with a pressure required for the fuel tank. A space is formed in an upper portion of the fuel tank so as to project therefrom.

Abstract: A four-stroke engine comprising an engine frame including a block and a head, the block forming at least one cylinder, and a crankcase. A piston is mounted for reciprocation in the cylinder, and a crank and connecting rod are mounted in the crankcase and connected to the piston. The head supports an intake valve, an exhaust valve, and a valve actuating mechanism, and a valve cover forms an enclosure with the head that encloses the valves and mechanism. The crankcase includes a fuel inlet port and an outlet port, and a duct connects the outlet port to the enclosure in the valve cover. The inlet port is connected to a supply of a combustible mixture comprising fuel, lubricating oil and air. During engine operation, the mixture flows through the crankcase from the fuel inlet port to the outlet port, the piston functioning as a pump to move the mixture. The oil in the mixture lubricates the engine parts in the crankcase.

Abstract: An apparatus for supercharging a four cycle internal combustion engine has at least one inlet reed or check valve and at least one outlet reed or check valve associated with each cylinder of the internal combustion engine. The crankcase of the engine is maintained air tight and if the engine is multi-cylindered, the crankcase must be provided with some form of air tight separation between each cylinder inside the crankcase. When the engine is rotating, each up-stroke of each piston causes an air charge to enter the respective crankcase section for that cylinder through its associated inlet reed or check valve. Each down-stroke of the piston causes compression of the charge in the associated section of the crankshaft and delivery of this pressurized charge through the associated outlet reed or check valve.

Abstract: In a supercharged 4-cycle engine including an intake passage connecting a fuel-air mixture forming section to a crank chamber, and a supercharging chamber connecting the crank chamber through an intake port to a combustion chamber, wherein when a piston is reciprocated to change a volume of the crank chamber, a fuel-air mixture is sucked from the intake passage into the crank chamber, and the fuel-air mixture compressed in the crank chamber is discharged into the supercharging chamber; a space accommodating a valve operating mechanism inclusive of a rocker arm is communicated with the supercharging chamber. Accordingly, even when a volume of the supercharging chamber itself is small, a supercharging volume 10-20 times a displacement of the engine can be substantially ensured.

Abstract: A 4-cycle internal combustion engine including a crankcase, a cylinder, a cylinder head, a piston adapted to reciprocate within the cylinder, a combustion chamber formed by the piston, the cylinder and the cylinder head, and a crankshaft connected to the piston via a connecting rod, is improved in order to enhance its thermal efficiency, to reduce exhaust emissions and to make it possible to operate the engine while the engine is in any attitude.

Abstract: An internal combustion engine having a bi-diameter or stepped piston configuration. The piston having a smaller upper piston portion and a larger lowre piston portion. A pumping chamber is formed in part by the larger lower piston portion separate from each of the crankcase and combustion chamber. Fluid reaches the pumping chamber from outside the pump/engine and is pumped-out beyond the pump/engine. The pumped fluid never communicates with either of the sealed crankcase or combustion chamber.

Abstract: An internal combustion engine having a bi-diameter or stepped piston between a combustion chamber and crankcase. Piston outlet means is provided in the smaller upper piston portion which permits mixture from the crankcase to pass through to a mixture channel. The mixture channel leads to ports in the upper cylinder portion forming the combustion chamber. A pumping chamber is formed in part by the larger lower piston portion seperate from the crankcase.

Abstract: A combustible mixture is compressed in the crankcase of a four-stroke cycle engine and forced into a boost plenum which houses the camshaft. The compressed mixture is metered by a throttle to intake valves of the engine. The engine is constructed from identical engine block elements rotated and joined to enclose the centrally disposed crankcase and common boost plenum with the cylinders horizontally opposed.