Title : Effects of ambient gas temperature on spray behavior and combustion characteristics in a biodiesel fueled diesel engine
Authors : Mingu Kang, Su Han Park, Sungwook Park, Chang Sik Lee
Speaker : Mingu Kang(MS course)
Abstract : The purpose of this study is to investigate the effects of ambient gas temperature on spray behavior, combustion, and exhaust emissions characteristics in a diesel engine operated by biodiesel fuel. For the spray behavior analysis, the spray images were obtained in a constant volume high-pressure chamber with various ambient gas temperatures, and they were measured by using a high speed camera. In order to analyze the effect of initial intake air temperature, the intake air was controlled by a heating coil, which was installed at an intake manifold around intake valve. In this study, the combustion characteristics for the variation of intake air temperature were measured and analyzed in a single-cylinder diesel engine with a compression ratio of 17.8 and a displacement volume of 373.3cc. In addition, for investigating exhaust emissions characteristics, nitrogen oxides (NOX), carbon monoxide (CO) and hydrocarbon (HC) were measured by an exhaust gas analyzer under the various intake air temperatures.
From experimental results, it revealed that the increase of ambient gas temperature in a constant volume chamber induced the increase of the spray tip penetration. The spray area also increased by the increase of ambient gas temperature. On the other hand, as intake air temperature rises, it can be observed that the NOX emission increased gradually, compared to the natural aspirated condition. The indicated mean effective pressure (IMEP) decreased because the occurrence of the auto-ignition was advanced with the increase of the intake air temperature.
Keywords: air/fuel ratio, equivalence ratio, intake air preheating, biodiesel, spray tip penetration, spray distribution,
spray atomization characteristic