| 摘要 |
A spectral method, and corresponding system, for knock detection includes acquiring spectral energy associated with vibration caused by a knocking condition from a running engine. Preferably, a sampled data system (105) acquires the spectral energy by converting an output from an accelerometer (101) into data samples (103) in a digital form. Then from the acquired spectral energy, a knock variable is derived from magnitudes of spectral components, representing a characteristic of a combution chamber located within the running engine. In a preferred embodiment the knock variable is derived from magnitudes of spectral components related by ratios corresponding to Bessel function coefficients. The preferred embodiment includes a Digital Signal Processor (109) applying a Fast Fourier Transform method to estimate a spectral content used to determine the knock variable. Then, a knock indication is provided when the knock variable exceeds a magnitude of a predetermined threshold. <IMAGE> |
