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In this study to develop a knock sensor for a high power engine, spark timing is selected as a design parameter and the knock factors are examined for 4-cycle 4-cylinder engine with different spark timing. Knocking occurrence crank angle, knocking pressure and knocking intensity are measured by a statistical method in which 10 data per 1 crank degree for 120 cycles are selected. Since, knock sensor detects cylinder wall vibration and estimates pressure vibration in a combustion chamber, cylinder pressure and engine block vibration are detected by pressure transducer and acceleration sensor, respectively, and these two signals are analyzed by frequency analysis method and compared with theoretical knocking mode in the combustion chamber. A design parameter of knocking sensor is determined by these results.

The purpose of this paper is to closely examine the influence of the behavior of fuel mixture in the intake manifold on combustion characteristics, performances of engine output and exhaust emission by using a 4-stroke spark ignition engine. In case of removing the liquid film fuel flowing on the wall of the intake manifold and of not removing it, the values of combustion characteristics such as the heat release delay, the combustion delay, the rate of heat release, the burned mass fraction and the maximum combustion pressure were obtained from the analysis of pressure indicator diagram. And then, the values of engine performance and concentration of exhaust gas were obtained.