Impact of Active-Grille Shutter Position on Vehicle Air-Conditioning System Performance and Energy Consumption in Real World Conditions

Active grille shutter (AGS) in a vehicle provides aerodynamic benefit at high vehicle speed by closing the front-end grille opening. At the same time this causes lesser air flow through the cooling module which includes the condenser. This results in higher refrigerant pressure at the compressor outlet. Higher head pressure causes the compressor to work more, thereby possibly negating the aerodynamic benefits towards vehicle power consumption. This paper uses a numerical method to quantify the compressor power consumed in different scenarios and assesses the impact of AGS closure on total vehicle energy consumption. The goal is to analyze the trade-off between the aerodynamic performance and the compressor power consumption at high vehicle speeds and mid-ambient conditions. These so called real world conditions represent highway driving at mid-ambient temperatures where the air-conditioning (AC) load is not heavy. AC system is modeled using 1D methodology and its performance simulated at system level. Net power consumed by the vehicle is computed for different scenarios using a robust comparison methodology. System model is validated against vehicle drive cell test data. Tests are conducted on a mid-size sport utility vehicle (SUV) equipped with a full face AGS. Simulations are then performed with the validated model using a Design for Six Sigma (DFSS) methodology to compute net power consumed by the vehicle by varying the blower setting, vehicle speed and ambient temperature. This paper provides guidelines regarding when to have the AGS closed or open for different noise factors considered.