Abstract: A fuel tank having an inlet and an outlet is connected to a separate pressure vessel by means of a pump. Fuel vapors are pumped out of the tank and into the pressure vessel while the tank is being filled via the inlet, so that fuel vapors cannot escape during filling. After filling, the inlet is closed and the pressure in the tank is increased to about 4 bar by means of a pressure regulator in a line connecting the pressure vessel to the fuel tank. The pump is then switched off and the fuel can be delivered to the engine via the outlet under the increased fuel pressure in the tank, the pressure being reduced to fuel system pressure by a pressure regulator in the outlet line.

Abstract: Disclosed is a fuel cell system comprising a fuel cell which includes a feed line for a fuel and a feed line for an oxidant. To ensure adequate moistening of the fuel cell membrane even during the start-up phase of the fuel cell, a fluid reservoir containing a fluid is provided, via which the fuel and/or the oxidant are humidified before entering the fuel cell. Thus adequate moistening of the fuel cell membrane is ensured even during the start-up phase of the fuel cell. To prevent the fluid from freezing at low temperatures, mixing of the fluid with an antifreeze is provided for. To ensure that the antifreeze will not pass into the fuel cell, the fluid drawn from the fluid reservoir is heated sufficiently by a heating means for evaporation of the antifreeze and separation from the fluid to take place. The heating means can include a flow conduit designed as a closed system. The flow conduit has a heating medium flowing through it which, prior to giving off heat to the fluid, is heated via a burner.