Patent ID: 7516732

Claim:
A method for detecting the beginning of combustion in an internal combustion engine ( 1 ) having several cylinders ( 2 , 3 , 4 , 5 ), from a rotation speed signal determined for a shaft ( 6 ) of the internal combustion engine ( 1 ), in which at least one segment signal (SS), whose signal length corresponds to an integral multiple of one or more full rotations of the shaft ( 6 ), is extracted from the rotation speed signal, so that each cylinder ( 2 , 3 , 4 , 5 ) ignites one time in the rotation angle range represented by the signal length, a cylinder signal (ZS 1 , ZS 2 , ZS 3 , ZS 4 ), which substantially reproduces the operational state in one of the cylinders ( 2 , 3 , 4 , 5 ), is generated from the segment signal (SS), the cylinder signal (ZS 1 , ZS 2 , ZS 3 , ZS 4 ) is transformed into a cylinder frequency signal (FS 1 , FS 2 , FS 3 , FS 4 ) in an angle frequency range, a signal information indicating the beginning of combustion in the associated cylinder ( 2 , 3 , 4 , 5 ) is extracted from the cylinder frequency signal (FS 1 , FS 2 , FS 3 , FS 4 ) at least one predefined angle frequency with regard to amplitude and phase values associated with the predefined angle frequency, and the beginning of combustion is detected from the signal information.