Knock control apparatus for internal-combustion engine

摘要

To obtain a knock control apparatus for internal-combustion engine having a function of judging whether or not the causes for failure have been solved for returning to normal knock control at the time of the solution, and capable of easily judging failure even in a failure mode in which it is difficult to raise the filter value and it is difficult to judge the failure. A fail control means 4 includes: a failure judgment unit 4 for judging failure for each cylinder based on output from a background level setting unit 2 and a knock suppression and control unit 3; number of fail cylinders judgment unit 42 for judging the number of fail cylinders based on output from the failure judgment unit 41; a retard angle changing unit 43 for changing at least the real retard angle of a fail cylinder based on output from the knock suppression and control unit 3, the failure judgment unit 41 and the number of fail cylinders judgment unit 42; and a normal judgment returning unit 44 for returning to normal ignition timing retard when a cylinder under judgment for failure meets normal judgment requirements based on the output from the background level setting unit 2 and the retard angle changing unit 43.