Development of an IC Engine Simulation Programme for Multiple Turbocharger Configurations

This paper describes the development of an engine performance simulation programme using both the method of characteristics (MOC) and the filling and emptying method (F&E) to optimise the use of computer time and achieve accurate simulation results, with the emphasis being given to the modelling of turbocharger compressors and turbines for different matching conditions. The possible turbocharger matching options are discussed, and the associated models are developed for multiple compressors and turbines. In these models, each inlet and outlet of the devices is modelled firstly, by using either the MOC or F&E method, or both, and then coupled to each other according to the matching option. The performance characteristics of both devices inputted in the form of performance maps, are converted into different forms with different matching options. Using this modelling method, the simulation programme is greatly enhanced in its capacity, extending its application to such a level that even computations for multi-turbocharger arrangements, either in series or in parallel, can be carried out with choices of average or pressure wave calculation. This added ability is particular useful, and indeed, it has shown its potential in turbocharged automobile engine research and development, in which sequential, step and supercharger combinations are applied.