A Semi-empirical Model to Predict Diesel Engine Combustion Parameters

To carry out the investigation, a cylinder pressure model was developed based on the position of the crankshaft, engine load, engine speed, and fuel injection time. This model takes into account the maximum number of parameters involved. The accuracy of the model was verified by experimental results. The average error of the cylinder pressure, the average radical of the square of the error of the cylinder pressure, and the average error of maximum pressure were calculated at 1.85%, 3.32, and 0.66% (of maximum pressure), respectively. This model was compared with the model by Conolly and Yagle; the two models are similar in terms of the pressure relating the square of time and the exponential of time. This model appears applicable to other diesel engines. The results of the equation and experimental results were compared and described by a Fourier series, which is indicative of the cylinder pressure level between them.