Method for determining a position of a rotating shaft

The present invention relates to methods for determining a position of a rotating shaft. A method for determining a position of a rotating shaft and, more particularly, for determining a sync position of an engine crankshaft or engine camshaft. The method includes sequentially measuring consecutive time periods generated in response to rotation of the shaft, and comparing each measured time period to a value calculated from a predetermined function based on more than one measured time period to determine the sync position. Preferably, the comparing step includes comparing a penultimate measured time period to a product of a sync factor and the sum of an ultimate measured time period, the penultimate measured time period, and an antepenultimate measured time period. After determining the sync position, the method includes sequentially measuring a predetermined number of consecutive time periods generated in response to further or continued rotation of the shaft, and comparing a penultimate measured time period to a value calculated from the predetermined function to verify the sync position.