Effects of injection parameters and intake air temperature on acetone-butanol-ethanol (ABE) blend HCCI-DI engine

Homogeneous charge compression ignition-direct injection (HCCI-DI) approach was reported to effectively eliminating the problems associated with HCCI engine while promoting HCCI combustion. Acetone-butanol-ethanol (ABE) fuel has been studied previously to replace butanol due to its lower production cost and time. This paper aims to extend the potentials of ABE fuel in HCCI-DI engine with other parameters such as intake air temperature, port injection timing and port injection pulse width also investigated. Diesel, ABE5 (5 % ABE and 95 % diesel by vol.) and ABE10 (10 % ABE and 90 % diesel by vol.) were used with different engine loads (1 Nm, 2 Nm, 3 Nm, 4 Nm and 5 Nm). Further experiments were carried out using ABE10 with different intake tem-peratures (60 degrees C, 80 degrees C, 100 degrees C, 120 degrees C and 140 degrees C), port injection timings (230 degrees CA BTDC, 250 degrees CA BTDC, 270 degrees CA BTDC, 290 degrees CA BTDC and 310 degrees CA BTDC) and port injection pulse widths (3 ms, 4 ms and 5 ms). It was found that increasing ABE ratio reduces the brake specific fuel consumption (BSFC) and increases the brake thermal efficiency (BTE) of the HCCI-DI engine. Up to 13.55 % and 23.8 % BTE improvement when ABE5 and ABE10 were used compared to diesel respectively. Furthermore, increasing the port injection pulse width increased the BSFC and reduced the BTE significantly by 10 % on average. Compared to diesel, ABE5 reduced the NOx emission by 20.2 % on average while NOx reduced by 24.8 % when ABE10 was used. Increasing the intake air temperature more than 100 degrees C significantly increased NOx by 54.1 % while HC decreased up to 23.2 % with 140 degrees C intake air temperature. Advanced port injection timing reduced the NOx emission by up to 24.7 %. NOx emission was reduced by 12.5 % as the pulse width increased from 3 ms to 5 ms due to higher premixed ratio combustion leading to lower combustion temperature. The combustion phasing of the engine was sensitive to the variation of intake temperature resulting in advanced start of combustion as the intake temperature increased. Besides, the combustion phasing reported to be steadily advanced as the pulse width increased which is showing its sensitivity towards the amount of port fuel injected. In conclusion, it was shown that ABE fuel is not only renewable but also capable of reducing emission without compromising the engine performance of HCCI-DI engine.