Method and device for the low-emission operation of a fuel cell tank system, especially of a motor vehicle

Abstract

The invention relates to a device for operating a fuel cell tank system of a motor vehicle which comprises a pump and valve assembly (11), an activated carbon filter (12), a fuel tank (14) and a control device (20). Said device also comprises safely valve, (31, 32) and a pressure switch (33). The assembly (11) contains a currentless bistable electromagnetic valve (40) which is connected to the control unit (20) via a line (41) and which can be controlled by a control module (42). The control unit (20) is connected to pressure and/or temperature sensors (45, 46) via lines (43, 44). The pressure sensors (45, 46) send pressure signals to the control unit (20) via said lines (43, 44). If, during the evaluation of the pressure/temperature data, the control module (42) anticipates the existence of a pressure in the fuel tank (14) that exceeds the ambient pressure after the vehicle has been switched off, the bistable electromagnetic valve (40) is opened in order to conduct the excess fuel vapor, in accordance with the direction of flow (47), out of the fuel tank (14) and into the area surrounding the vehicle via the activated carbon filter (12). However, in the instance that a low pressure is anticipated, the bistable electromagnetic valve (40) is closed or remains closed, whereby a leak test of the fuel tank system can be carried out using low pressure.

Dependencies are inferred from the claim text.