Patent ID: 6873930

Claim:
A method for detecting a rotational speed of an internal combustion engine which exhibits periodic speed oscillations, a crankshaft having a sector wheel being connected to the internal combustion engine, the method comprising the steps of: scanning the sector wheel connected to the crankshaft at a scanning location; determining a time taken for a sector having a sector size to pass the scanning location; retrieving operating-parameter-dependent correction factors from a characteristic map, the operating-parameter-dependent correction factors being development coefficients for modeling the periodic speed oscillations which occur during operation of the internal combustion engine, wherein the operating-parameter-dependent correction factors are development coefficients of one of a Taylor series and a Fourier series; and correcting the determined time by determining a corrective adjustment for the periodic speed oscillations using the operating-parameter-specific correction factors and obtaining a corrected time using the determined time and the corrective adjustment.