PREDICTION OF THE THERMAL INJURY AROUND EXHAUST SYSTEM OF PASSENGER CAR BY PRACTICAL PROCEDURE ' 1st Report: DEVELOPMENT OF 1D MODEL FOR HEAT ANALYSIS '

摘要

In case that heat injury performance is analyzed with CFD, large calculations are required to solve heat and mass flow field inside the exhaust pipes, in the engine compartment and around vehicle body simultaneously. Since it spends much time for the generation of the analytic models and their solution by full CFD, such calculations are not practical to the industrial development of the vehicle in which many parameter studies on various conditions are required. Wherein, we suggest new method for prediction of the heat injury on exhaust systems, which is simplified with 1 dimensional models though the engine compartment flow is calculated with 3 dimensional calculations, i.e. CFD. Basic idea of this method is to divide exhaust systems into several elemental modules where heat transfer characteristics are given individually and to imitate actual systems by connecting them. Then 3D calculation is processed coupling heat and flow field with radiant filed outside exhaust systems. Above all, chemical reaction occurs in the catalytic converter is solved carefully to estimate heat production. This report introduces an overview of their 1-dimensional model and the calculation results.