Comparison of Predictive Gasoline Combustion Models Using GT-Power

Abstract

With rising fuel prices and stringent emission regulations, OEMs are constantly working on improving the performance, fuel efficiency and reducing emissions of the internal combustion engines. Gas exchange simulation tools plays a very important role in the development of new concepts. Simulation tools helps to reduce the lead time significantly in developing new concepts. The engine performance is dependent on the combustion efficiency which is analysed through burn rate. But measuring burn rate during the combustion is a difficult task. One of the major tool developers Gamma Technologies have developed a predictive combustion model which predicts the burn rate using the cylinder pressure. Calibration of the models is important for obtaining reliable results. Volvo Car Corporation (VCC) use FKFS combustion model for the development of the gasoline engines. Using a different combustion system requires recalibration of the combustion model to develop new concepts. The aim of the thesis is to calibrate and validate the two predictive combustion models, SI Turb and FKFS in GT-Power and comparison of the models in order to assist future development of Gasoline engines at VCC. Predicting capabilities of the two calibrated combustion models is evaluated by its ability to predict the main operating parameters such as IMEP, Peak pressure, CA at 50% burn fraction and Ignition delay. Calibration of the model is done against the test data obtained from a single cylinder test rig and the data was validated for different errors before using it for calibration. The predicting capabilities for FKFS combustion model is good for the complete engine map, whereas SITurb combustion model predicts well only for the calibrated range.