Abstract: A four-stroke internal combustion engine is supercharged by admitting fuel-air mixture into the engine crankcase and compressing the mixture on the down stroke of the piston. The engine cylinder, and the piston disposed therewithin, are of stepped configuration defining a combustion chamber above a smaller, top piston portion, and an annular chamber above a larger, lower piston portion. Compressed mixture from the crankcase is admitted to a pressure reservoir for supply to the combustion chamber via an intake valve and a throttle valve. The crankcase is either supplied with fuel-air mixture from the annular chamber, or supplies fuel-air mixture to the reservoir via the annular chamber, so as to provide two stages of compression.

Abstract: An internal combustion heat engine and cycle therefor comprising a two stroke cylinder and piston unit having a combustion chamber at the top of the cylinder, having a compression chamber at the bottom of the cylinder, and having a transfer chamber charged with compressed combustion support air transferred into the combustion chamber during initial movement of the piston in a first power stroke, followed by spark ignition and combustion to effect said power stroke with simultaneous compression in said compression chamber and with admission of compressed combustion support air into said transfer chamber during terminal movement of said power stroke, the compressed combustion support air being stored in the transfer chamber during a second exhaust stroke with simultaneous induction of air into the compression chamber.

Abstract: An internal combustion heat engine and cycle therefor comprising a two stroke cylinder and piston unit having a combustion chamber at the top of the cylinder, having a compression chamber at the bottom of the cylinder, and having a transfer chamber charged with compressed combustion support air transferred into the combustion chamber during initial movement of the piston in a first power stroke, followed by spark ignition and combustion to effect said power stroke with simultaneous compression in said compression chamber and with admission of compressed combustion support air into said transfer chamber during terminal movement of said power stroke, the compressed combustion support air being stored in the transfer chamber during a second exhaust stroke with simultaneous induction of air into the compression chamber.

Abstract: A crankcase supercharged four cycle engine (10) includes an outside air inlet port (22) positioned so that upon each expansion stroke of the piston (11) a discrete pulsed charge of pressurized air is fed to the crankcase (15), and hence from the crankcase through a one-way valve (26) into surge tank (28). The surge tank chamber (29) is connected through a tuning pipe (31) to a manifold volume chamber (34) leading to the air intake (20) of the engine cylinder (12). The tuning pipe is designed with the correct length and volume to provide a resonant frequency which increases engine torque at low speed. The construction provides a closed loop connection (24) between the crankcase and engine cylinder which is subjected to air pressure pulses which are directly responsive to the frequency of reciprocation of the piston. A pressure multiplier effect is obtained within the loop to substantially increase the pressure of air ultimately fed to the cylinder.

Abstract: A crankcase supercharged four cycle engine (10) includes an outside air inlet port (22) positioned so that upon each expansion stroke of the piston (11) a charge of pressurized air is fed to the crankcase (15), and hence through a one-way valve (25) and nozzle (26) into an enclosed surge tank (28). A tuning pipe (30) disposed within the surge tank has an inlet (31) at the nozzle outlet and provides a tuned passage which connects for discharge through a valved port (20, 21) into the engine cylinder (12). On one downward stroke of the piston, air from the outside air inlet port is compressed into the crankcase and is forced through the one-way valve and nozzle to provide a charge of compressed air which is trapped within the surge tank and tuning pipe. On the next downward stroke of the piston, another charge of compressed air is forced through the nozzle and into the tuning pipe inlet.

Abstract: An internal combustion engine having a piston assembly such that gaseous flow into a cylinder is through the piston assembly and wherein all gaseous flow in a cylinder is in a single direction. The piston assembly includes inner and outer piston members which are relatively movable so as to form a gaseous passage therethrough in certain conditions. The engine also features a special valve mounting arrangement and a special crankshaft construction.