Generalized engine systems modeling, methodology and validation.

摘要

The goals of this research are to develop and validate a detailed transient dynamics engine system model. The model has general characteristics that may allow it to be implemented in real-time control and diagnostics of engine systems performance. With the introduction of emissions predictions the model can have an additional application in the optimization of the performance of advanced systems including the control of the aftertreatment systems.; This thesis presents a generalized modular engine modeling structure, developed using MathWorks' MATLAB/Simulink software, which can be used in developing dynamic models of internal combustion engines or other dynamic powertrain models. A generalized block used in developing these models is discussed in detail, and specific applications of this block are shown within an overall engine model. A discussion of how this approach addresses typical modeling issues, which arise when modeling dynamic systems, is included. The details of an example diesel engine system model are given with the physical equations used to model the various system components.; The development of simplified system-level emissions modeling approach is also presented, and an assessment of the computational savings in the simplified method is discussed, with an illustration of the magnitude of the errors introduced by the simplifications.; An overview of the experimental setup used in the validation phase is presented, with a detailed discussion of the experimental technique developed to measure transient exhaust gas flow rates. Also, an experimental investigation was conducted to test the validity of using the steady state turbocharger performance data to predict transient performance. Finally, parameter identification and validation examples are presented for the specific engine.; The validation was first done on the individual components level, and then the overall system validation is performed by comparing the predictions of the integrated system model with the measurements. The results of the comparison present a remarkable agreement between the model and the data.