Method and apparatus for verification of a predetermined fuel mixing ratio

The verification process is applied to an injection system (1) for an internal combustion engine (BKM) with at least two separately stored types of fuel (KS1, KS2). When the second type of fuel is supplied, or when the supply is changed from the first type of fuel to the second type of fuel, the fuel volume supplied through the injection system is reported, and the presence of a preset fuel mixture ratio (KMV1-KMVx) is verified.