Experimental investigation of cyclic variation in a diesel engine using wavelets

Abstract

In this study, cyclic variations of combustion parameters (IMEP and THR) are analyzed using morlet wavelet transform in a diesel engine. Experiments were conducted at 1500 rpm for different engine load conditions and compression ratios. Combustion parameters were calculated from measured cylinder pressure trace. In-cylinder pressure data of 2500 consecutive engine cycles were acquired and processed for the analysis of cyclic variations. Results revealed that cyclic variability in THR decreases with increase in engine load and compression ratio. Cyclic variability is highest in idle load conditions at lowest compression ratio. Low frequency cyclic variations are observed at low loads conditions and with increase in engine load variations shift to high frequency range. Results can be utilized for the development of effective engine control strategies.