Diagnosis appts. for testing combustion conditions of multicylinder IC engine - measures revolution rate for each cylinder and computes state parameter deviations using stored function patterns

摘要

The appts. measures the revolution rate for each engine cylinder and a combustion state parameter is computed depending on the revolution rate. The combustion state of a defined cylinder is diagnosed from the state parameter. Function patterns related to the deviation of revolution rate dependent combustion state parameters are stored. A compensation arrangement operates during correction of the function patterns and afterwards on the basis of the measured revolution rates and computed state parameters and computes the deviation of the state parameter for the revolution rate of the defined cylinder. A correction arrangement corrects the computed deviation and sets the corrected value as the new combustion state value. USE/ADVANTAGE - For diagnosing combustion states in cylinders of multicylinder engines from revolution rate differences of cylinders. Accurate diagnosis e.g. w.r.t. misfire is achieved over large revolution rate range independently of engine and changes in engine characteristics with time.