Second Law Analysis of Diesel Engine by Using Different Ignition Delay Models

A mathematical model is developed for comparing different ignition delay models for compression ignition engine fuelled with the diesel under different operating load. The model developed is single zone zero dimensional model. The different ignition delay models are used to compare the different. Once the heat release rate is modelled the pressure and temperature are predicted for every crank position. The diesel engine is considered as closed system for thermodynamics analysis. The cylinder gases are assumed as ideal gas the different developed ignition delay model is validated against the data obtained by experimentation at laboratory. This study again elaborated how properties of cylinder charge gases varying with the crank angle position. By performing the experimentation on diesel engine, experimental results have been compared with models given by Arrhenious, Wolfer, Watson and Hardenberg. It is found that experimental results are in good agreement with Arrhenious model. Heat transfer to the cylinder wall from cylinder gas has taken into account to find the gross heat release rate. Heat transfer coefficient correlation given by Hohenberg has been used to calculate convective heat transfer. Radiative heat transfer has been neglected. For predictive analysis two functions have been used, one for premixed part and Wiebe function for diffusion part. Different ignition delay correlation to predict start of combustion has been used, i. e. Watson, Wolfer, Arrehenius and Hardenberg and Hase. Simulated curve for ROHR has been tuned with experimental curve for various load conditions to find out the shape parameters of the functions. Correlation for these shape parameters are modified with adjusting coefficients, using the least square curve fitting method. The properties of in-cylinder gas have been calculated by various polynomial equations which are the main function of temperature. The ignition delay correlations are compared.