Ascertaining running irregularity value of IC engine - deriving correction term from medians formed from time spans differences of ignition phases

摘要

At least one crankshaft angle sector related to the t.d.c. of each cylinder before its ignition phase is set out. The sector time spans for each ignition phase during which the given crankshaft angle sectors are covered are measured. A first difference is formed from two sector time spans for each ignition phase. This provides a basic running deviation term. A correction term for running deviation is obtained. The running deviation value is obtained by correcting the basic term through subtraction of the correction term. The correction term is derived through medians formed from several sector time span differences for ignition phases of interest. ADVANTAGE - Median deviation ensures that not only linear but also at least a partial class of non-linear accelerations and decelerations can be fully compensated. Running irregularity value not affected at all.