| A quasi-dimensional, multi-zone, direct-injection diesel combustion model has been developed and implemented in a full cycle simulation of a turbocharged engine. The combustion model accounts for transient fuel spray evolution, fuel-air mixing, ignition, combustion and NO and soot pollutant formation. In the model, the fuel spray is divided into a number of zones, which are treated as open systems. While mass and energy equations are solved for each zone, a simplified momentum conservation equation is used to calculate the amount of air entrained into each zone.; The model is validated with experimental data obtained in a constant volume chamber and real engines. First, predictions of spray penetration and spray angle are validated against measurements in a pressurized constant volume chamber. Subsequently, predictions of heat release rate, as well as NO and soot emissions are compared with experimental data obtained from representative heavy-duty, turbocharged diesel engines.; It is demonstrated that the model can predict rate of heat release with high fidelity across a wide range of operating conditions. NO and soot emissions predictions also show good agreement with experimental data. However, additional effort is required to enhance the fidelity of NO and soot emissions predictions across a wider range of operating conditions. |
