Impact of acetone-butanol-ethanol (ABE) and gasoline blends on the energy balance of a high-speed spark-ignition engine

ABE is considered as a potential alternative fuel for internal combustion engines, but few studies have paid on the energy balance when the engine is fuelled with ABE. In this paper, pure gasoline, ABE10 (10 %vol ABE blended with 90 %vol gasoline), ABE20 and ABE30 were tested on a high-speed spark-ignition (SI) engine under the operating conditions of 4000 r/min at 35% throttle position and 8000 r/min at 45% throttle position. The energy balance, the performance, and the combustion characteristics of the test engine were analyzed under the operating conditions of the maximum brake power (MBP) at lambda = 1, the MBP at fuel-rich and the minimum brake specific fuel consumption (BSFC). The results have shown that with the increasing of ABE blend ratio, the brake thermal efficiency (BTE) and the percentage of the unburned fuel of the engine are increased. However, increasing the ABE content decreased the percentage of exhaust energy and heat losses. The exhaust emissions show a strong relationship with lambda, and achieve a higher value when the engine fuelled more ABE, which leads to more unburned energy put out of the engine. In addition, increasing the ABE ratio in the ABE/gasoline blends could reduce the in-cylinder peak pressure and temperature, thus affecting the energy balance. The study of this paper has shown that the lower ratio of ABE blended in gasoline presented a good application prospect in high-speed SI engine.