The invention proposes a method and an emulsifying apparatus for the operation of a diesel engine with a water-diesel fuel emulsion, wherein the water fraction is varied as a function of the engine operating point andor the emulsifying apparatus andor parts of the injection line are flushed with pure diesel fuel upon a shutdown of the engine. The apparatus includes a first buffer, a second buffer, a third buffer, a blending engine and a display engine. An electrical sensor detects movement of the magnets relative to the vehicle-engaging surface of the magnet housing. As a next step, a p-type silicon thin film is deposited at the front side of the substrate.