Method and apparatus for operating an LPG fuel Mono Fuel motor

A method of controlling a fuel system with a liquid gas as a fuel, in particular LPG or LNG fuel in a vehicle, wherein a motor (6) by means of an ignition key (13) is started directly or indirectly by the presence and operation of a separate starting member, wherein a flow process is automatically prior to the active ignition of the motor (6) by the user of the vehicle is activated, wherein the liquid state of the fuel in a feed line (8) to an injection pump (5) ensures or produce, and in which the flow process at least the following the steps of: - distance detection of the ignition key (13) to a vehicle-related reference location, - detecting the pressure and temperature of the fuel by means of at least one sensor (15), - starting a thermodynamic preparation phase by acting on the in a feed line (8) to an injection pump (5) located fuel. The invention also relates to a fuel system which is suitable for performing the method. The thermal preparatory phase includes at least one bypass step in which by means of a fuel pump (4) fuel is circulated, wherein a bypass line (30) is provided, which from the supply line (8) in the region of the suction side of an injection pump (5) for suction side of the fuel pump (4) is guided, in the bypass line (30) is cooled at fuel in the bypass step.