Patent ID: 7240647

Claim:
A piston engine having at least one dry-running piston-cylinder unit comprising a first housing ( 1 ); at least one cylinder ( 2 ) arranged in or on the first housing ( 1 ) and a piston reciprocably movable therein; a first crankshaft ( 4 ); a second crankshaft ( 5 ); the first and second crankshafts ( 4 , 5 ) being parallel and rotating synchronously in opposite directions; axes of rotation (X, X′) of the crankshafts ( 4 , 5 ) extending parallel to a center plane (Z) of the cylinder and being laterally offset relative thereto; first and second piston rods ( 6 , 7 ) associated with piston ( 3 ) so that a first end of the first piston rod ( 6 ) is rotatably mounted relative to piston ( 3 ) and a second end thereof is rotatably mounted on a crank pin ( 40 ) of the first crankshaft ( 4 ), and wherein a first end of the second piston rod ( 7 ) is rotatably mounted on piston ( 3 ) and a second end thereof is rotatably mounted on a crank pin ( 50 ) of the second crankshaft ( 5 ); synchronization gears ( 46 , 56 ) in engagement with each other and connecting the crankshafts ( 4 , 5 ) with each other; and a second housing which includes a lubricant, the crankshafts ( 4 , 5 ) being journalled relative to the second housing and arranged so that a first end of each crankshaft ( 4 , 5 ) sealingly projects from the second housing ( 8 ) preventing lubricant from escaping from the second housing into the first housing; the crank pins ( 40 , 50 ) and the respective piston rods ( 6 , 7 ) connected thereto being arranged in the first housing ( 1 ) and outside the second housing ( 8 ).