CI engine CO2 emission High speed PIV Mahalanobis distance NOx emission index PPCI diesel engine T1-995 TA1-2040 acoustic alternative fuel biofuel canola oil (Co) combustion combustion modelling combustion noise combustion optimization combustion waste heat common rail compression ignition computational fluid dynamics condensation effect continuously variable valve systems critical back pressure detailed chemistry detonation combustion diesel engine diesel fuel (Df) diffusion flames direct injection driving cycles