Patent ID: 8215268

Claim:
A three-stroke internal combustion engine having first and second pistons movably connected to a single crankshaft for reciprocating motion toward and away from each other within a single cylinder during a single revolution of said crankshaft, said single revolution including an exhaust/intake stroke, a compression stroke, and an expansion stroke, said cylinder having a first open end proximate said crankshaft and having inlet ports proximate the first end, and having a second end distant from said crankshaft and closed by a head having formed therein an exhaust passage, said pistons defining therebetween an intake chamber and said second piston defining with the head a combustion chamber, wherein during at least a part of said exhaust-intake stroke, the exhaust passage is open to said combustion chamber, and said crankshaft causes said second piston to move toward the head and away from said first piston, thereby exhausting burned gases from said combustion chamber, and during at least a part of said exhaust-intake stroke, said crankshaft causes said first piston to move away from said second piston, thereby opening the inlet ports to aspirate an air-fuel mixture into said intake chamber; wherein, during said compression stroke, the exhaust passage and the inlet ports are closed, and said crankshaft causes said first piston to move toward and abut said second piston, thereby forcing the air-fuel mixture past said second piston into said combustion chamber; wherein, the exhaust passage and said inlet ports remaining closed, ignition of the air-fuel mixture to form burned gases, and consequent expansion of the burned gases in said combustion chamber, causes motion of said pistons away from the head, at least said first piston causing said crankshaft to move through said expansion stroke of said single revolution, said expansion stroke being followed by said exhaust-intake stroke.