<p>The driving apparatus has a liquefied petroleum gas (LPG) tank (10) that is connected to a combustion chamber (2) having a movable piston. A metering device (4) is arranged between the tank and combustion chamber for ejecting a defined amount of fuel from a dosing volume into the combustion chamber. An electrically operated three-way valve with two switching positions is provided in the metering device for blocking flow of fuel from the dosing volume.</p>
