Knock detection apparatus and knock detection method

Abstract

A knock detection apparatus which is capable of changing a knock control starting time period appropriately so as to prevent erroneous knock determination, to thereby expand a knock control range. A peak value acquisition unit acquires a peak value of a vibration of an internal combustion engine during each rotation cycle of a crankshaft of the engine. A background calculator calculates a background by averaging peak values acquired by the peak value acquisition unit. A knock determination unit performs knock determination based on whether a peak value acquired by the peak value acquisition unit is higher than a predetermined level above the background, and feedback controls knock in the engine according to a result of the knock determination. A temperature acquisition unit acquires a temperature of the engine during a start of the engine. A knock determination controller inhibits operation of the knock determination unit until a predetermined time period determined according to the engine temperature acquired by the temperature acquisition unit has elapsed.