Combustion Model for a Homogeneous Turbocharged Gasoline Direct-Injection Engine

Abstract

Homogeneous charge is a preferred operation mode of gasoline direct-injection (GDI) engines. However, a limited amount of work exists in the literature for combustion models of this mode of engine operation. Current work describes a model developed to study combustion in a homogeneous charge GDI engine. The model was validated using experimental data from a 1.6 L Ford EcoBoost® engine, tested at the U.S. EPA. The combustion heat release was approximated using a double-Wiebe function, to account for the rapid initial premixed combustion followed by a gradual diffusion-like state of combustion, as observed in this GDI engine. Variables of Wiebe correlations were adjusted into a semipredictive combustion model. The effectiveness of semipredictive combustion model was tested in prediction of in-cylinder pressures. The root-mean-square (RMS) errors between experiments and numerical results were within 2.5% of in-cylinder peak pressures during combustion. The semipredictive combustion model was further studied to develop a predictive combustion model. The performance of predictive combustion model was examined by regenerating the experimental cumulative heat release. The heat release analysis developed for the GDI engine was further applied to a dual mode, turbulent jet ignition (DM-TJI) engine. DM-TJI is a distributed combustion technology with the potential to provide diesel-like efficiencies and minimal engine-out emissions for spark-ignition engines. The DM-TJI engine was observed to offer a faster burn rate and lower in-cylinder heat transfer compared to the GDI engine.

Experiments and modeling of a dual-mode, turbulent jet ignition engine

“…The trend observed is in agreement with the results reported by Assanis et al 32 for the ignition delays of a direct-injection diesel engine. Tolou et al 25 observed the same trend for ignition delays of a gasoline direct injection (GDI) engine. However, the former study reported an increase in ignition delays as the load further increases and exceeds 120 N m of brake torque at high-boost conditions.…”

“…The most important difference lies in the treatment of heat transfer coefficients when the intake and exhaust valves are open, and intake inflow velocities and exhaust backflow velocities increase the in-cylinder heat transfer. More information can be found in the work done by Tolou et al 25 under “Numerical Approach and Model Development.”…”

A Study on Extreme Learning Machine for Gasoline Engine Torque Prediction

“…In the past, various engine or engine subsystem models have been proposed by the researchers. For instance, Tolou et al have presented a semi-predictive model of a homogeneous turbocharged gasoline direct injection engine [3]. The model approximates the combustion heat release with a double-Wiebe function and predicts the cylinder peak pressure by tuning the Wiebe variables.…”