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Alternative fuels such as butane and DME have different properties including high vapor pressure, low viscosity, and low surface tension, compared to other conventional fuels. These properties may lead to different atomization characteristics such as liquid core breakup, droplet size distribution, and evaporation process. To investigate these effects, a method based on shadowgraph technique to take spray images for droplets and surrounding gas was tested and evaluated. Experiments were performed at low injection pressure for early stage direct injection. It could be concluded from the results that the proposed method could be used to investigate the structure of evaporating spray, and the vapor layer around the spray core could be correlated to the turbulent mixing length for both of butane and DME sprays by observing vapor and spray core.

Detailed chemical kinetic model of hydrogen peroxide (H2O2) into diesel exhaust gas has been executed to investigate its effect on the removal of nitric oxide(NO) by changing exhaust gas temperature and H2O2 addition amount. Flux analysis has also been done to clarify which reaction mainly affects NO-to-NO2 conversion. From the results of this study, it is shown that the optimal temperature condition to maximize the removal of NO exists near at 500K for OH addition condition, while that for H2O2 addition exists near at 800K. It is also shown that temperature window for the removal of NO becomes widened as the initial temperature of the exhaust gas increases, and NO-to-NO2 conversion rate decreases in proportion to the concentration of hydrocarbon(HC), although that of the total NOx remains the same level regardless of HC concentration. Finally, it is shown that HO2 + NO → NO2 + OH is mainly responsible for NO-to-NO2 conversion.

This paper describes the method to detect S. I. engine misfire for the OBD II requirement. In most methods related to the misfire detection, the fluctuation of crankshaft speed is used as an input parameter[1, 2, 3, 4 and 5]. If the misfire detection is performed by the pattern of crankshaft speed without considering the engine dynamics, it is difficult to determine the misfire at high speed and low load condition. So this paper proposed the single degree of freedom energy model of engine dynamics for the misfire detection. Through this model the integral of torque by cylinder pressures are estimated using the variation of crankshaft speed and it is possible to detect the misfire by this integral value.

This paper describes to measure the cylinder pressure in a SI engine using the variation of crankshaft speed. Assuming engine dynamics as a single degree of freedom the energy equation is derived. Through some assumptions each cylinder pressure can be estimated form the pressure torque. Through this study cylinder pressures by this method show good accord with measured value in low to medium speed ranges. For more accurate analysis the crank angle based modeling of friction and vibration is required.