FORFARANDE OCH ANORDNING FOR APPROXIMATIV BESTEMNING AV TIDPUNKTEN FOR ETT ONSKAT VINKELLEGE HOS EN ROTERANDE KROPP

摘要

An apparatus and method for predicting the time occurrence of the desired angular position of a rotating body, such as the crankshaft of an internal combustion engine. The apparatus includes means for storing a nonlinearly changing count that is set to a known starting value when the rotating body is at a known angular position. A computing means is included for computing the value of the count that corresponds to the time when the rotating body will be at the desired angular position. The computation is achieved by extrapolating from known count information based upon prior periods of angular displacement of the rotating body during periods of known duration. In addition, the apparatus includes means for reducing the error associated with extrapolating the desired angular position of a rotating body undergoing either acceleration or deceleration by basing the extrapolation on a known period of angular displacement that occurred earlier than the most recent period of rotation immediately prior to the extrapolation process.