Bahram Bahri - Automotive Engineering Department, Shahreza Branch, Islamic Azad University, Shahreza, Iran
Azhar Abdul Azizi - Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, Automotive Development Centre, Malaysia
Ali Salavati-Zadeh - Vehicle, Fuel and Environment Research Institute(VFERI), University of Tehran, Tehran, Iran
Vahid Esfahanian - School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran

Ethanol as a renewable and alternative fuel when utilized in homogeneous charge compression ignition (HCCI) has potential to substantially reduce nitrogen oxides (NOx) and particle matter (PM) and can maintain HCCI sustainability. HCCI engine operation is limited between two ringing and misfire regions that too retard and advance combustion phasing highly affect HCCI engine operation, performance and emissions. In this study, a modified 0.3 liter single-cylinder direct-injection diesel engine has used with a fuel port injection system. A study has done on effect of ethanol combustion on engine performance and emission by varying incoming air temperature and fuel/air mixture which focused on the zones near ringing and misfire regions. The results indicate that too retarding combustion phasing makes HCCI combustion unstable that affects combustion temperature lower than normal combustion which result in reducing indicated mean effective pressure and producing higher hydrocarbon (HC) and carbon monoxide (CO) emissions and too advancing combustion phasing generates high peak pressure rise rate with rapid combustion and reduces IMEP but amount of CO and HC is lower in this situation.

HCCI, ethanol, performance, emissions