Wavelet analysis for cyclic combustion dynamics of a multi-cylinder CRDI diesel engine fuelled with a blending of argemone biodiesel–diesel oil

Abstract

Higher cyclic variability in combustion adversely influences emissions, efficiency, and driveability of internal combustion engines. In this paper, we used wavelet transform techniques to investigate the dynamical characteristics of a combustion process in numerous combustion parameters of a 4-cylinder turbocharged common rail direct injection (CRDI) diesel engine fuelled with Argemone mexicana biodiesel (AGB)/diesel blended fuel. In addition, statistical analysis is described to validate the results of the wavelet spectrum methods for cyclic variation in the diesel engine. The results show that the cyclic variations in IMEP and Pmax are sensitive to the engine load and fuel properties. The coefficient of variation of both combustion parameters decreases as engine load increases for all tested fuels. Moreover, adding Argemone mexicana biodiesel (AGB) into diesel fuel up to 20% (AB20) reduces cyclic variations in combustion parameters at all tested engine loads. Furthermore, the global wavelet spectrum and wavelet power spectrum are utilized to identify the dominant oscillatory combustion modes. The cycle-to-cycle fluctuations in combustion parameters (i.e., IMEP and Pmax) exhibit multi-scale dynamics for all experimental conditions. Compared to long and intermediate oscillations in diesel fuel, AB10 and AB20 fuel showed short and intermittent period fluctuations. The findings of this experimental work will be helpful to optimize engine control strategies for AGB/diesel blended fueled multi-cylinder CRDI diesel engines.

An experimental investigation into the combustion stability and emissions of an n-butanol/diesel blended fueled partially premixed compression ignition (PPCI) engine

“…Furthermore, statistical parameters cannot characterize the time series’ spectral fluctuations or internal evolution. 5…”

“…The square modulus of CWT represents the wavelet power spectrum (WPS), which is derived using equation (5). 34 It denotes the quantity of signal energy at a given location and frequency.…”

“…21,22,[28][29][30] They have been efficiently used for signal analysis in a variety of applications and primary research sectors. 5,11,21,[31][32][33] Furthermore, WT is utilized to calculate the amplitude of cyclic variability, the periodicity of its existence, and the time over which it endures. This input can be used to modify and control the system.…”

“…Recent research has also concentrated on the combustion stability problems in CI engines, 20,23 while there has been minimal research on identifying the dynamical complexity of combustion fluctuations in diesel engines. 24,25 Kumar et al 5 estimated the wavelet power spectrum (WPS) and global wavelet spectrum (GWS) of maximum cylinder pressure (Pmax) and indicated mean effective pressure (IMEP) to investigate the combustion stability of a 4-cylinder CI engine operating on argemone-Mexicana biodiesel/diesel blended fuels. Despite increasing the biodiesel blend level to 20%, the effect of biodiesel blended with diesel fuel on cyclic variability is more pronounced at 15% load conditions.…”

“…for further studies on alternative fuels in diesel engines. [4][5][6] Moreover, scholars have been motivating the investigation of numerous advanced combustion strategies (i.e. homogeneous charge compression ignition (HCCI), partially premixed combustion (PPC), premixed charge compression ignition (PCCI), and reactivity controlled compression ignition (RCCI)) by employing renewable high research octane number (RON) fuel and various tools such as RSM, WPS, 0-1, etc.…”