Internal combustion engine

The invention relates to an internal combustion engine, in detail, an internal combustion engine having a cylinder inside which a piston is reciprocatingly supported. The piston defines a combustion chamber constructed in the cylinder and drives a crankshaft which is rotatably supported in a crankcase; at least one flow passage is disposed for connecting the inner cavity of the crankcase with the combustion chamber at least one position of the piston, and is let into the crankcase by a let-in opening and into the combustion chamber by an overflow window; wherein the let-in opening and the overflow window are offset from each other on the circumference of the cylinder; a cylinder jacket is disposed in the cylinder to form at least one wall section; the cylinder has an upper cylinder segment and a lower cylinder segment which are separated from each other and are manufactured separately. Thus, the internal combustion engine can be manufactured by casting die.