Optimization of a Vehicle Under Hood Airflow Using 3D CFD Analysis

With stringent requirements of fuel efficiency and emissions, the airflow and thermal management within the under-hood environment is gaining significance day by day. While adequate airflow is required for cooling requirements under various vehicle operating conditions, it is also necessary to optimize it for reduced cooling drag and fan power. Hence, the need of the day is to maximize cooling requirements of Condenser, Radiator, CAC and other heat exchangers with minimal power consumption. To achieve this objective and due to the complicated nature of 3D flow phenomenon within the under-hood environment, it is useful to perform 3D CFD studies during preliminary stages to shorten design time and improve the quality and reliability of product design. In this paper we present the results from a CFD under-hood analysis that was carried out for design, development and optimization of a CRFM (Condenser, Radiator and Fan Module). The objective of the current study was to perform a full 3-D CFD under-hood analysis and optimize CRFM airflow using improved sealing and fan shroud modifications with speed flaps and vanes. Based on packaging constraints and target requirements of A/C and engine cooling, proper components were selected and airflow improved via CFD analysis and design modifications. Further a study was also carried out at IDLE to assess airflow recirculation and its effect on A/C performance