Patent ID: 7475682

Claim:
A method for determining, during a start-up phase, the timing of an indirect injection internal combustion engine comprising a crankshaft and a camshaft, in which the following steps are performed: turning over the engine from a starting position (A 1 , A 2 , A 3 , A 4 , A 5 , A 6 ); detecting a plurality of uniformly distributed marks ( 8 ) of a first target ( 6 ) of a first sensor ( 2 ), the first sensor comprising a first stationary part ( 4 ) and the first target ( 6 ) connected to the crankshaft; detecting at least one of a plurality of fronts (F 1 , F 2 , F 3 , F 4 , F 5 , F 6 ) of a second target ( 16 ) of a second sensor ( 12 ), the second sensor comprising a second stationary part ( 14 ) and the second target ( 16 ) connected to the camshaft, said second target having a more or less circular cross section and comprises: a plurality of teeth (D 1 , D 2 , D 3 ) extending over angular sectors of different magnitudes, a plurality of gaps (C 1 , C 2 , C 3 ) extending over angular sectors of different magnitudes, and the plurality of fronts (F 1 , F 2 , F 3 , F 4 , F 5 , F 6 ) separating the teeth (D 1 , D 2 , D 3 ) and the gaps (C 1 , C 2 , C 3 ), the second stationary part ( 14 ) configured to detect the teeth (D 1 , D 2 , D 3 ), the gaps (C 1 , C 2 , C 3 ) and the fronts (F 1 , F 2 , F 3 , F 4 , F 5 , F 6 ) on the second target ( 16 ); detecting, on the first target ( 6 ), a reference index ( 10 ) detectable by the first stationary part ( 4 ); counting the marks ( 8 ) detected on the first target ( 6 ) from the starting position (A 1 , A 2 , A 3 , A 4 , A 5 , A 6 ); if the reference index ( 10 ) on the first target ( 6 ) is detected by the first stationary part ( 4 ) before a front (F 1 , F 2 , F 3 , F 4 , F 5 , F 6 ) is detected on the second target ( 16 ) by the second stationary part ( 14 ), then comparing a number of marks ( 8 ) counted between the starting position and the detection of the reference index ( 10 ) against a reference threshold; and if the counted number of marks is greater than said reference threshold, then deducing the engine timing with the counted number of marks.