Effect of Copper Coating on Extended Expansion SI Engine 2007-32-0012

The concept of Extended Expansion (EE) in Internal Combustion (IC) engines though very old is gaining importance now a days due to the scope it possess in areas of fuel economy and engine emissions. In this paper, a single cylinder engine with variable expansion to compression ratio (ER/CR) was analyzed for its performance when copper coating is done on the surface of cylinder head - piston combination. Copper element that can promote pre-flame reaction was coated on the surface of cylinder head and piston. ER/CR ratio was varied with Late Intake Valve Closing Time (LIVCT) and the load was controlled with LIVCT-VCR combination. LIVCT was achieved by Electronic Valve Timing (EVT) system using solenoid valve. Due to the catalytic effect of copper coating it was found that for the copper coated EE engine, the brake thermal efficiency was improved by 4% compared to standard engine operating at same conditions. It was found that for ER/CR ratio equal to 1.5, the copper coated EE engine was giving best performance in terms of thermal efficiency and Lean Misfire Limit (LML). The LML of the engine was extended up to 0.75.