Experimental investigations of performance, combustion and emission characteristics of ethanol and methanol fueled HCCI engine

• HCCI operating window decreases with increasing engine speed.
• Methanol shows lower IMEPmax compared to gasoline and ethanol.
• Third order polynomial shows variation of combustion duration with SOC timings.
• Methanol auto-ignites earlier than gasoline and ethanol in HCCI mode.
• Combustion duration in HCCI operating range is less than 15 CAD.
• Alcohols have higher ringing intensity for optimum combustion phasing.

Homogeneous charge compression ignition (HCCI) engines have potential to provide both diesel like efficiencies and very low NOx and particulate matter (PM) emissions. There is growing global interest in using alternative biofuels in order to reduce the reliance on conventional fossil fuels. Therefore this experimental study was carried out to investigate performance, combustion and emission characteristics of HCCI engine fueled with ethanol and methanol and compare it with baseline gasoline fuel. The experiments were conducted on a modified four-cylinder four-stroke engine at different engine speeds using port fuel injection technique for preparing homogeneous charge. To achieve auto-ignition of air–fuel mixture in the combustion chamber, intake air pre-heater was used. In-cylinder pressure data acquisition with subsequent heat release analysis and exhaust emission measurements were done for combustion and emission diagnostics. In this paper, effect of intake air temperature and air–fuel ratio on combustion parameters, thermal efficiency, combustion efficiency, ringing intensity and emissions in HCCI engine is analyzed and discussed. Results show that methanol and ethanol are good replacements to gasoline in HCCI combustion mode.