（1.Key Laboratory of Shaanxi Province for Development and Applicationof New Transportation Energy,Chang＇an University,Xi＇an 710064,China;2.Department of Delivery Equipment Support,Academy of Military Transportation,Tianjin 300161,China;3.Great Wall Motor Company,Baoding 071000,China）
In order to reduce the emissions of diesel engine fueled with biodieseldiesel blended fuel mixed at medium proportion, the performance differences between biodiesel-diesel blended fuel and pure diesel fuel were analyzed and the influences of ethanol blending ratio on economy, power and emission characteristics were studied by mixing the blended fuel with 10% and 20% of ethanol respectively under different loads of 1 400 r/min and 2 000 r/min. The results show that the brake specific fuel consumption and NOx emission of biodieseldiesel blended fuel increase and the power and soot emission decrease. With the increase of ethanol blending ratio, the brake specific fuel consumption of biodiesel-diesel-ethanol blended fuel increases. The effective thermal efficiency decreases at low load due to the influence of latent heat from ethanol vaporization, is little influenced at medium load, and increases at high load due to the high oxygen content of ethanol. The maximum power of engine decreases with the increase of ethanol blending ratio under full load conditions of 1 400 r/min and 2 000 r/min. With the increase of ethanol content in biodieseldieselethanol blended fuel, the soot, NOx and CO emissions decrease gradually under different loads. In addition, the HC emission increases obviously due to the high latent heat caused by strong vaporization of ethanol at low load.
