Misfiring cycle pressure measurement for diesel-converted HCCI engine

Homogeneous charge compression ignitions (HCCI) engines represent promise as an alternative to spark ignition and diesel engines. Misfire and partial burn can cause several serious problems in HCCI engines operation and exhaust after-treatment systems. In this study, a 0.3 liter single-cylinder direct-injection diesel engine was modified to operate on HCCI mode. Artificial misfire was produced by fuel supply system cut-off to measure in-cylinder pressure. Analysis of misfire focusing on in-cylinder pressure sensor data was conducted in a converted-diesel HCCI engine fuelled with ethanol. Maximum in-cylinder pressure (P_max), indicated mean effective pressure (IMEP), in-cylinder pressure at 10, 15 and 20 CAD aTDC, maximum pressure rise rate (MPRR) and third derivative of in-cylinder pressure were acquired to find which metric gives the best combination for realtime misfire detection. The results indicated that IMEP, Pmax and in-cylinder pressure at 10, 15 and 20 CAD aTDC are good metrics for misfire detection in HCCI.