Method for estimating the crank angle at which 50 of the fuel mass has been burnt in a cylinder of an internal combustion engine with spontaneous mixture ignition

摘要

A method for determining the angular speed of a drive shaft of an internal combustion engine at each tooth event of a phonic wheel presenting a number N of teeth includes detecting the angular amplitude for each tooth; detecting the time of each tooth; and determining the raw angular speed of each tooth according to the corresponding angular amplitude and time. For each tooth a compensation value is determined which represents the difference between the actual angular amplitude of the tooth and the theoretic angular amplitude of the tooth; and determining the angular speed of each tooth by correcting the raw angular speed based on the corresponding compensation value.