Large Scale Multi-Disciplinary Optimization and Long-Term Drive Cycle Simulation

Abstract

Market demands for increased fuel economy and reduced emissions are placing higher aerodynamic and thermal analysis demands on vehicle designers and engineers. These analyses are usually carried out by different engineering groups in different parts of the design cycle. Design changes required to improve vehicle aerodynamics often come at the price of part thermal performance and vice versa. These design changes are frequently a fix for performance issues at a single performance point such as peak power, peak torque, or highway cruise. In this paper, the motivation for a holistic approach in the form of multi-disciplinary optimization (MDO) early in the design process is presented. Using a Response-surface Informed Transient Thermal Model (RITThM) a vehicle's thermal performance through a drive cycle is predicted and correlated to physical testing for validation. Furthermore, an MDO using RITThM is demonstrated with tradeoffs and important trends identified and described along with optimal design points. Potential sources of error, areas for improvement, and potential applications of an MDO using RITThM are presented.