Patent ID: 6474302
Filing Date: 2002-11-05
Classification: F02D,F02P,Y02T

Abstract:
A knock control apparatus for internal-combustion engine, comprising:ionic current detection means for generating a signal corresponding to a knock based on ionic current; background level setting means for filter-processing a knock detected signal value from said ionic current detection means to set a background level, which serves as a knock criterion, based on a filter value; knock suppression and control means for judging the knock based on said knock detected signal value and said background level to control at least ignition timing retard; and fail control means for performing control when knock detection cannot be properly performed, wherein said fail control means comprises: failure judgment means for judging failure for each cylinder based on output from said background level setting means and said knock suppression and control means; number of fail cylinders judgment means for judging a number of fail cylinders based on the output from said fail judgment means; retard angle changing means for changing at least the retard angle of a fail cylinder based on the output from said knock suppression and control means, said fail judgment means and said number of fail cylinders judgment means; and normal judgment returning means for returning to normal ignition timing retard when a cylinder under judgment for failure meets normal judgment requirements based on the output from said background level setting means and said retard angle changing means.