Gas petrol engine

The gas Otto engine comprises a cylinder, in which a piston (1) is movable, and an externally generated gas-air mixture, which is combustible in a combustion chamber limited by a cylinder head, cylinder walls and a piston head (2). The piston head comprises an asymmetrical piston cavity (7). A non-rotational symmetric elevation (8) extends in the interior of the piston cavity. Independent claims are also included for the following: (1) a method for manufacturing a gas Otto engine; and (2) a method for operating a gas Otto engine.