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A new multidimensional calculation method has been developed to simulate the warm-up characteristics of close-coupled catalytic converter systems. First, a one-dimensional gas exchange simulation and a three-dimensional exhaust gas flow calculation are combined to simulate the pulsation gas flow caused by the gas exchange process. The gas flow calculation and a heat transfer calculation are then combined to simulate heat transfer in the exhaust manifold and the catalyst honeycomb under pulsation flow. The predicted warm-up characteristics of the systems examined agreed well with the experimental data. In this simulation, CPU time was reduced greatly through the use of new calculation methods. Finally, the warm-up process of close-coupled catalysts is analyzed in detail with this simulation method. The design requirements for improving warm-up characteristics have been made clear.

A low-temperature, premixed combustion concept, called Modulated Kinetics (MK) combustion, has been developed that reduces emissions of nitrogen oxide (NOx) and smoke simultaneously. This new combustion concept requires heavy exhaust gas recirculation (EGR) to reduce the NOx emission and combustion noise. However, there is an interaction between the effects of controlling exhaust gas recirculation (EGR) and the variable geometry turbocharger (VGT). This makes controlling both the EGR rate and air mass flow rate more difficult under transient operating conditions. Therefore, the authors investigated a cooperative control of EGR and VGT in an effort to control the accuracy of both the EGR rate and the air mass flow rate. This paper presents an approach through the application of a control system CAD program and rapid prototyping tools to improve transient operating states by referring to a model-based EGR and VGT control algorithm.