Patent ID: 8250910

Claim:
A method for incrementally ascertaining a rotation angle of a crankshaft of an internal combustion engine, the shaft being connected to a sensor wheel having teeth and tooth gaps, and at least one sensor being associated with the sensor wheel, the method comprising: generating, by the sensor, a square-wave signal as an output signal which assumes a first value or a second value; assigning a signal edge to a tooth edge, a position in time of a counteredge with respect to the edge encoding a direction of rotation, and an assignment of a direction of rotation reversal point to a tooth of the sensor wheel or a tooth gap of the sensor wheel being encoded by the position in time of the counteredge with respect to the edge; and ascertaining the rotation angle by adding an increment to a counter for each signal edge; wherein, after a direction of rotation reversal while a tooth passes the sensor, a half-increment, having a sign of the direction of rotation after the direction of rotation reversal, is incremented once, and in an event of a direction of rotation reversal while a tooth gap passes the sensor, a half-increment, having a sign of the direction of rotation prior to the direction of rotation reversal, is incremented once.