Direct Injection Diesel Engine Rate of Heat Release Prediction using Universal Load Correction Factor in Double Wiebe Function for Performance Simulation 2011-01-2456

A proposed modification or an innovation can be analyzed quickly using a computer simulation and cost overrun in setting up an experimental work can be minimized by the optimization of experimental parameters beforehand. Literature data for performance prediction of direct injection diesel engine operated either with diesel fuels having property variation or with oxygenated diesel blends were found mostly confined to experimental investigations only. In modern research, computer simulation has become a powerful tool for diesel engine performance prediction as it saves time and is also economical in the analysis of modifications. In a finely tuned and warm engine, the thermodynamic models are capable of reproducing cylinder pressure and over all engine performance with acceptable accuracy over a wide range of operating conditions. In this paper, a novel approach of applying the universal load correction factor in double wiebe function model along with a linear late combustion model and the two-zone concept to model diesel combustion has the advantage of rapidly providing apparent rate of heat release, cylinder pressure, mean cylinder temperature and concentration variations also with significantly less computing resource requirement. Any improvement predicted in the combustion heat release rate of an engine fuel will enhance the performance and reduce the emission simultaneously under identical heat input and operating conditions. Therefore a rapid combustion heat release rate predictive capability is necessary to support the global simultaneous performance enhancement and pollution control strategy. In this paper an initiative is taken to predict combustion heat release rate and performance of a direct injection diesel engine with reasonably acceptable accuracy by using a universal modeling methodology in "C" language. A typical direct injection diesel engine (bore x stroke: 92 x 96 mm, compression ratio: 17.7 & speed 960 rpm) operated with diesel for which the Society of Automotive Engineers International (SAE International) Journal-published experimental investigation data were already available is taken for this simulation research purpose. Apparent heat release rates synthesized with the help of universal load correction factor in double wiebe function model along with a linear late combustion model have been found agreed very closely with the experimental investigation. The synthesized results of performance such as brake specific energy consumption and brake thermal efficiency for various power outputs have been found agreed with reasonably acceptable accuracy.