Method for determining the angular position of an engine by way of a crankshaft sensor and a camshaft sensor

A method for determining an angular position of an engine by way of a crankshaft sensor comprising a crankshaft detector facing a crankshaft toothed wheel, performing two revolutions per engine cycle, and comprising a large number of regular teeth and a revolution marker, the crankshaft detector being able to produce a ‘tooth’ event corresponding to an edge for each of said teeth, a ‘revolution’ event for the revolution marker, and a ‘missing tooth’ event when two successive ‘tooth’ events are abnormally far apart, and of a camshaft sensor comprising a camshaft detector facing a camshaft toothed wheel, performing one revolution per engine cycle, and comprising a small number of irregular teeth, the camshaft detector being able to produce a ‘tooth start’ event for each rising edge and a ‘tooth end’ event for each falling edge, the method comprising:

• producing the ‘revolution’ event by the crankshaft sensor,
• determining with the camshaft sensor the angular position of the camshaft by identifying the ‘tooth start’ and ‘tooth end’ events produced by the camshaft detector following said ‘revolution’ event, in a fast mode, over at most one crankshaft revolution, wherein if a ‘missing tooth’ event is produced by the crankshaft detector after the ‘revolution’ event and if the determination of the angular position of the camshaft fails, the method continues with a step of:
• determining with the camshaft sensor the angular position of the camshaft by identifying the ‘tooth start’ and ‘tooth end’ events produced by the camshaft detector, in a slow mode, over at least two crankshaft revolutions.