Title : Study on effects of biodiesel fuel in diesel-bioethanol-biodiesel blended fuels on fuel properties and exhaust emissions characteristics
Authors : Su Han Park, Junepyo Cha, and Chang Sik Lee
Speaker : Su Han Park (Ph.D)
The fuel properties and fuel component ratio are very important factors in the analysis of the combustion and exhaust emissions characteristics. In diesel-bioethanol blended fuels, the biodiesel fuel should be necessary added to prevent the phase separation. The purpose of this study is to investigate the effects of biodiesel fuel on the fuel properties, the combustion, and the exhaust emissions characteristics in diesel-bioethanol-biodiesel blended fuels. In the condition with a fixed bioethanol blending ratio of 20%, biodiesel fuel added to diesel-biodiesel blended fuels from 5% to 20% as volumetric ratio. Spray behaviors such as the spray distribution, spray tip penetration are measured by the spray visualization system, which consist of the high-speed camera and metal-halide lamp. The spray images of test fuels are captured as bottom- and side-view type. The combustion and exhaust emissions characteristics are measured and analyzed in a single cylinder diesel engine, which has a 373.3cc of the displacement volume and 17.8 of the compression ratio.
From the experiments results, it revealed that the increase of biodiesel blending ratio caused the increase of the fuel density and the surface tension. However, the kinematic viscosity maintained as similar level, regardless of biodiesel blending ratio. The effect of biodiesel blending on the spray development and tip penetration is insignificant. In the combustion, the ignition delay decreased and the IMEP decreased with biodiesel contents. The nitrogen oxides (NOx) emission was reduced by biodiesel fuel due to its low lower heating value (LHV). The soot emission was also reduced by biodiesel fuel due to its oxygen contents. In hydrocarbon (HC) and carbon monoxide (CO) emissions, both emissions were reduced with the increase of the biodiesel fuel because the oxygen in biodiesel fuel helps the combustion activity. From these experimental results, it can be concluded that the use of biodiesel fuel in diesel-bioethanol blended fueled engine can solve the problem as the deterioration of combustion performance by bioethanol fuel.
Keywords: diesel-bioethanol-biodiesel blended fuels, nitrogen oxides (NOx), soot, hydrocarbon (HC), fuel properties