Patent ID: 8656762

Claim:
A method for detecting a first rotation angle of a first shaft of an engine, the method comprising: providing a first marking carrier with sensor-readable markings, the markings forming a first marking pattern, the first marking pattern has marking sections having at least one first marking section and a second marking section, the first marking carrier being caused to be rotated by a first shaft, wherein there is a proportionality between a rotation angle of the first shaft and a rotation angle of the first marking carrier; scanning the first marking carrier by a first sensor; generating a first sensor signal by the first sensor during the scanning, the first sensor signal being modulated via the markings on the first marking carrier; and providing a computing unit having a memory unit with a memory area with stored marking sections having at least one first stored marking section and a second stored marking section, a sensor signal input, and a timer with a time signal, wherein a correlation between a time course of the first sensor signal and the time signal is made by the computing unit, the computing unit performing the process steps of: a) recovering a first marking section from the first sensor signal; b) determining a first exclusion criterion for excluding the first stored marking section from the recovered first marking section; c) excluding the first stored marking section via the first exclusion criterion; d) checking whether a difference of a total number of stored marking sections minus a number of excluded stored marking sections is equal to one then the computing unit proceeds to process step (g) or if the difference is greater than one then the computing unit proceeds to process step (e); e) recovering a further marking section from the first sensor signal, an additional exclusion criterion is determined, and an additional stored marking section is excluded via the additional exclusion criterion; f) carrying out process step (d) again; and g) deriving the first rotation angle from the non-excluded stored marking section.