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The combustion characteristics of a diesel engine were examined by means of cyclic variation of combustion pressure and heat release history. In this paper the gas pressure, the rate of pressure rise, heat release rate and the other combustion characteristics of direct injection type diesel engine are investigated for the various pressure crank angle history using a combustion analyzing apparatus. Statistical analysis of combustion characteristics of diesel engine have been carried out over a various range of speed, fuel injection timing, and the several factors using a combustion data of five hundreds cycles of combustion analyzer. The results of this investigation show that the variations of combustion characteristics does change as cycle conditions are altered. The influences of cyclic parameter and operational factors on the combustion characteristics of engine are discussed also.

This paper describes the effects of two stage combustion strategy on the engine performance and the exhaust emission characteristics in a compression ignition engine. The two-stage combustion strategy targets reduction of NOx emissions by decreasing oxygen concentration for second stage combustion. Thus, the first injection was provided in order to consume in-cylinder oxygen, rather than generate power. A multi-dimensional CFD code was utilized to predict engine performance and emission characteristics. For the accurate and efficient computational calculation of ignition and combustion characteristics of diesel fuel, the reduced n-heptane mechanism was used in this study. The calculation for two-stage combustion was performed after validating against the experimental result. The KH-RT breakup model and gas-jet model was applied for the prediction of spray behavior and characteristics. To calculate the ignition and combustion process, CHEMKIN II [1] code was used.