A piston internal combustion engine with at least one gas exhaust valve (2) for each cylinder (1), which is actuated by an actuator (7), in particular an electromagnetic actuator, controlled by a fully variable engine control unit (15). Based on the predetermined operating cycle, the valve can close off the cylinder interior space against a gas exhaust channel (13) that follows the valve seat (3) of the exhaust valve. This channel is connected to an exhaust gas system and is provided with a means for example a constriction (14) for reducing the pressure gradient during the start of the opening of the gas exhaust valve (2). A specific pressure fluctuation is used for a further reduction in the pressure gradient behind the exhaust valves during the opening through a corresponding layout of the pipe geometry and the container volumes in the exhaust gas system or corresponding installed components.