Method of estimating the duration of target wheel teeth

Abstract

A method for determining as a function of time the angle of rotation of a crankshaft by estimating the position of missing teeth on a target wheel is disclosed which has application to engine control. A sensor acquires, as a function of time, a periodic signal comprising a pulsating waveform, each pulse indicating the passage of a tooth past this sensor. The position of a missing pulse on the signal is estimated from a missing tooth on the target wheel, by: estimating, during a cycle N, a time interval S between the passage past the sensor of a tooth dpreceding the missing tooth d and the passage past the sensor of a tooth dfollowing missing tooth d, by means of the time interval between the passages of the same teeth during the previous cycle N−1 then, estimating the position of the missing pulse in this interval S, according to the position of the pulses in time interval A between the passage past the sensor of tooth d−r and the passage past the sensor of tooth d−r during cycle N, with the engine being a j-stroke (2 or 4) engine and comprising k cylinders and a target wheel with l teeth, including the missing tooth; finally, determining as a function of time the crankshaft rotation angle by the modified signal.