An Experimental Study Of A Passenger Car Diesel Engine Fueled With Butanol-Diesel Blends

Due to the global energy crisis and increasing pollution from the vehicle emissions, development of clean alternative fuels for internal combustion engines has been brought to the forefront by researchers throughout the world. In this work, some tests were carried out on the intermiscibility and stability of the mixture of butanol and diesel and the load experiment at different engine speeds for four butanol-diesel blending ratios (0, 20%, 30% and 40% buthanol). Their influences on the combustion process, power output, fuel comsumption and emissions were analyzed. Based on two typical working conditions, bench tests were done to analyze how the blends influence the weighted fuel economy efficiency.Results showed that the intermiscibility and stability of the directly mixed butanol-diesel blends are good enough and there is no consolvent is needed. The mixture can keep stable and unstratified for a long time, which can help to popularize the butanol fuel.The experiments on the combustion characteristics indicated that the cylinder pressure of the blend fuels were higher than that of the pure diesel. With increase of the butanol proportion, the maximal explosion pressure and the maximal pressure increasing rate all went up to a limited degree. Under the light load condition, the ignition retarding period of the blended fuels was longer than that of the pure diesel. With the increase of the load, the period of the ignition retarding and the period of the combustion duration had the tendency of shortening.The experiments also showed that the effect on the fuel comsumption and power output was small even though the proportion of butanol was 40%. From the perspective of energy conservation, the blended fuel helps to improve the energy utilization in a diesel engine. With the increase of the butanol-diesel ratio, the NOx emissions of the blends were a little higher than that of the pure diesel, while the reduction of soot emission was quite obvious. Meanwhile, under light load condition, the HC emissions for the blends went up. However, they were almost the same as those of the pure diesel under high load conditions. Under light load conditions, the CO emissions increase with the increase of the butanol ratio, but under high load conditions, the trends was opposite.The experiments demonstrated that the increase ratio of the fuel consumption did not exceed 5% for the studied passenger vehicles when the butanol-diesel fuel was used.To sum up, butanol is a prospective alternative fuel and has a great application potential for diesel engines. A high blending ratio of butanol to diesel can be used and the power and fuel economy of the engine can be maintained.