Patent ID: 9157825
Filing Date: 2015-10-13
Classification: F02D,F02P,G01L

Abstract:
1. A knock diagnostic module, comprising: a digital signal processor (DSP) that performs N Fast Fourier Transforms (FFTs) during a knock window around a firing event of a first cylinder based on output from a vibration sensor measured during N different periods during the knock window to produce N sets of FFT points, respectively, wherein N is an integer greater than or equal to 2; a data reduction module that: a processing module that determines whether knock occurred based on the single intensity value and an average intensity value determined for the first cylinder; a knock module that increments a sample count for the first cylinder in response to the firing event of the first cylinder and selectively increments a knock count for the first cylinder based on whether knock occurred; a knock analysis module that analyzes the knock count of the first cylinder when the sample count of the first cylinder reaches a predetermined value and selectively generates an excessive knock signal when the knock count exceeds a predetermined threshold; a low variation module that determines a variation for the first cylinder based on a difference between the intensity value and a second intensity value determined for a previous firing event of the first cylinder; a low variation analysis module that selectively generates a low variation signal for the first cylinder when an average of the variation and at least one other variation of the first cylinder is less than a predetermined value and that determines the predetermined value based on an engine speed and an engine load; an abnormal range module that selectively generates an abnormal range signal when the intensity value is outside of a predetermined range and that determines the predetermined range based on the engine speed and the engine load; and a remedial action module that selectively performs a remedial action based on the excessive knock signal, the abnormal range signal, and the low variation signal.