Knock control device for engine

摘要

A knock control device is provided in which erroneous knock detection can be reduced by suppressing sudden knock signal changes due to noise, without causing any increase in the number of matching steps, deterioration in the S/N in knock detection and decrease in detection performing frequency. In the knock control device, an open gain is applied to the detected signal only during a knock detection window set in advance by a knock window setting means. The window corresponds to a period in which vibration due to knock arises. During other periods, either a closed gain or an interpolated gain value is applied to the detected signal.

主权项

1. A knock control device for an engine, comprising:
a knock sensor that detects vibration due to knock of the engine; a digital signal processing unit that performs a time-frequency analysis based on output from the knock sensor during a digital signal processing period set in advance; a knock window setting unit that calculates as a knock signal a peak-hold value in a knock window set in advance with respect to the processing result by the digital signal processing unit and calculates as a knock signal position a position where the knock signal is calculated; a knock detection unit that calculates a knock determination threshold value using the knock signal and detects the knock by comparing the calculated knock determination threshold value with the knock signal; and a knock suppression unit that suppresses the knock based on the detection result by the knock detection unit and the knock signal position; wherein the knock window setting unit sets in advance as a knock detection period (open period) a period in which the vibration due to the knock arises, multiplies the processing result by the digital signal processing unit by an open gain in the knock detection period and multiplies the processing result by the digital signal processing unit by a closed gain in periods outside the knock detection period (closed periods), in addition, a predetermined interpolation period is provided between the open period and each closed period, and in the interpolation period, the unit multiplies the processing result by the digital signal processing unit by a linear interpolation value between the open gain and a predetermined interpolation gain.