Internal combustion engine

Claim 1

An internal combustion engine comprising an axially extending cylinder having a head at one end and a bottom at the other, a piston arranged to reciprocate in said cylinder and to define with said cylinder, in combination with said head, a power chamber and, in combination with said bottom, an air compression chamber, said piston, as it reciprocates within said cylinder, has a lower dead center position adjacent the bottom end of said cylinder, a first intake port and an exhaust port each formed in the head end of said cylinder and communicating with the power chamber therein, means for supplying a fuel-air mixture to said first intake port for introduction into said power chamber, ignition means for initiating a combustion of the fuel-air mixture in said power chamber, means for controlling flow through said first intake port and said exhaust port, wherein the improvement comprises a partition forming a sealed closure for the bottom end of said cylinder, a second intake port connected to said cylinder below the lower dead center of said piston, means for controlling said second intake port, said piston arranged to perform a power stroke in said cylinder in response to the combustion of the fuel-air mixture within said power chamber with said piston terminating the power stroke in the lower dead center position, transfer means for transferring compressed air from said compression chamber to said exhaust port at the termination of said power stroke, said transfer means comprises a first opening from said cylinder in the bottom end thereof below the lower dead center of said piston, a second opening in said cylinder located below the head end thereof and above said piston in its lower dead center position, a transfer duct located exteriorly of said cylinder and interconnecting said first and second openings, said transfer means including a valve located in said transfer duct, a branch duct connected at one end to said transfer duct intermediate said first said openings and at its other end to said exhaust port at a location spaced outwardly from said cylinder, and said valve arranged to direct flow through said transfer port from said first opening to one of said branch duct and said second opening.