Evaluation of Impact of Active Grille Shutter on Vehicle Thermal Management 2011-01-1172

Due to increased demand for improved fuel economy and reduction in CO2 emissions, active grille shutter (AGS) has been considered as one option to increase fuel economy by reducing vehicle drag resistance. An AGS system will allow airflow through the grille when demand on cooling system or air conditioning system is high. Under conditions of light load and moderate ambient temperatures and humidity, the grille does not have to be fully open. A reduction in the effective grille size opening can be achieved by either partially or fully closing the grille through a stepped speed motor actuator. When the grille opening size is reduced, under-hood airflow will decrease. Therefore, the operating points for the grille shutter should take into account the effect of temperature rise for under-hood and underbody components and the performance of the cooling and climate control systems. In this paper, a series of tests have been designed and conducted to evaluate the effect of the grille shutter on the air conditioning (AC) system performance, and power train cooling as well as under-hood and underbody components temperatures. Tests have been designed to determine the impact of AGS on the AC compressor and fan power consumptions, cooling system and climate control system performance. Tests were selected to cover wide range of ambient temperature, humidity, vehicle speed, and climate control settings. In this paper, the experimental test results are analyzed and presented. Recommendations for the selection of the grille shutter operating points are based on these test results, functional requirements of vehicle systems and components, and overall fuel economy benefits.