Transient One-Dimensional Thermal Analysis of Automotive Components for Determination of Thermal Protection Requirements

During initial phases of vehicle development process, it is usually required to understand the temperature profile for all components. It is usually more effective and less costly if the thermal issues are determined and addressed before actual vehicles are built. Computational Fluid Dynamics (CFD) analysis tools are typically used for thermal management of the vehicle environment. However, for transient thermal analysis problems, running a full CFD requires solving the mass, momentum, and energy equations. This typically requires a lengthy computation time and extensive computer resources. The problem becomes more challenging when trying to conduct CFD analysis for several design iterations and for different duty cycles that may be of a transient nature. Therefore, the application of one-dimensional analysis early in the development phase can help point out the areas of prime concern. Therefore, more accurate component temperature estimates using CFD tools can be conducted after most of the issues are screened out.

In this paper, a one-dimensional thermal analysis model is applied to determine the temperature of different components in the under-body and under-hood areas under transient test cycles. Empirical values for heat transfer coefficients and averaged airflow around different components are used to determine the component temperatures. Analytical and test results for transient test conditions such as city traffic and build up are presented.