Thermal Management and Energy Consumption Balanced Design for Active Grill Shutter Control 2022-01-0187

Abstract

The active grill shutters (AGS) on the vehicle have been widely used in recent years due to increased demand on fuel economy and CO2 emission. The closed AGS helps to reduce air drag by preventing air going into underhood, which results in less engine torque and less fuel consumption. The AGS also need to ensure adequate cooling air for radiator, condenser and other components in the underhood, so that the control strategy should be carefully designed for both thermal management and energy consumption. A sport utility vehicle (SUV) equipped AGS is analyzed, and the AGS control strategy is developed with the help of simulation and experiment. Drag coefficients for series of shutter rotation angles are evaluated using a 3-D full-vehicle model. The maximum air drag coefficient benefit is found to be 9 counts, and most of the benefit is obtained around fully closed status. The fan control is considered as inputs for AGS strategy design, and a four-requirement strategy is developed. A chassis dynamo experiment is conducted in a climate wind tunnel to determine the best AGS control strategy aiming at minimum energy consumption as well as ensuring thermal management. The control strategy is programmed on the vehicle and tested in WLTC cycle, which demonstrates a reasonable shutter angle response and stable engine coolant temperature. The fuel economy benefit in WLTC is also measured, which shows 2% reduction in contrast with the fully open status.