Diesel Engine Cycle Simulation with a Reduced Set of Modeling Parameters Based on Detailed Kinetics

An investigation on reducing the set of modeling parameters for engine cycle simulation is presented. The investigation considers a detailed kinetic model for combustion and emissions predictions coupled to a complete cycle simulation tool applied to a modern Diesel engine. The analysis is based on a previously developed method that combines a 1-D gas dynamics model with a stochastic reactor model for direct injection engines (SRM-DI). Initially, the global and instantaneous performance parameters of a Diesel engine were simulated at different operating conditions. The model was validated and the simulated results were compared to experimental data to assess the quality of the model. Afterwards, the influence of the chosen modeling parameters on engine performance, such as in-cylinder pressure, emissions and global performances, were analyzed. The mixing time proved to be the most important modeling parameter for the stochastic reactor model. Its influence on engine model was therefore examined which included also tests with time dependent mixing time. The investigations revealed that by using a kinetics based approach for Diesel engines, the combustion and emission sub-models can be simultaneously set up with the same set of modeling parameters. This significantly simplifies and speeds up the overall modeling process while maintaining good predictability of engine performances.