Patent ID: 6867691
Filing Date: 2005-03-15
Classification: G01L

Abstract:
1. A knock determining apparatus for an internal combustion engine, comprising: a knock sensor for detecting knock in the internal combustion engine; a crank angle sensor for detecting a rotational angular position of a crank disposed in the internal combustion engine; a filter in which a filtering frequency band is variable, the filter for filtering a detection output of the knock sensor; a level discriminating unit for discriminating an output of the filter with respect to a given determination level in response to the output of the filter; a counter for counting number c of times at which the detection output of the knock sensor is not lower than the determination level in response to an output of the level discriminating unit; a determining unit for determining whether knock occurs or not on a basis of the counted number c in response to an output of the counter; and a correcting unit, in response to an output of said determining unit, for shifting the filtering frequency band of the filter when it is determined that determination of occurrence of knock is impossible.