The key challenges of passenger car today are to reduce carbon dioxide and to clean up exhaust gas emission. HCCI engine needs the following for practical use: wider operating range, combustion changing, and robustness control for different usage situation (e. g. fuel quality, parts variant). In this report, detection technology of combustion fluctuation and combustion noise on HCCI combustion mode was studied for constructing robustness control. The feature of this technology is to estimate combustion fluctuation and noise with rotational fluctuation of crankshaft and engine Vibration. As a result of bench engine test, an availability of this technology was confirmed.