Abstract: The invention relates to an operating method for a regeneration valve of a fuel vapor retention system, particularly of a tank vent valve for regenerating an activated carbon filter during which the regeneration valve is controlled by a control signal, whereby the control signal corresponds to a designated valve position of the regeneration valve. The invention provides that the correlation between the control signal and the resulting valve position of the regeneration valve is determined during a calibration process.

Abstract: The invention relates to a device for determining the quality of fuel for an internal combustion engine, comprising a pressure sensor (1) for determining the pressure (p) inside a fuel tank and/or comprising a temperature sensor (4) for determining the temperature (T) inside a fuel tank. According to the invention, an evaluation unit (5) is provided for determining a quality value (Q), which depicts die quality of the fuel, based on the temperature (T) and/or the pressure (p) inside the fuel tank. Said evaluation unit is connected on the input side to the pressure sensor (1) and/or to the temperature sensor (4).

Abstract: The fill level of an activated-carbon canister is calculated during the regeneration process in a lean burn combustion engine. While the engine is in idle operation, the fuel mass reduction that is adjusted by a momentum-based idle controller is used as a measure of the hydrocarbon mass flow that is delivered in the regeneration process, when the activating-carbon filter is flushed back into the engine via its intake tract.