Date of Award


Publication Type

Master Thesis

Degree Name



Mechanical, Automotive, and Materials Engineering

First Advisor

Ting, David


AC, active grille shutter, AGS, compressor power



Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.


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 to flow through the cooling module which includes the condenser. This results in a higher head pressure (AC compressor discharge pressure of the refrigerant). Higher head pressure causes the compressor to work more thereby possibly negating the aerodynamic benefits. This thesis shows a model-based method to quantify the fuel consumption in different scenarios to justify the AGS position (fully open or fully closed) to have better fuel economy. The impact of AGS is more felt at highway speed, so the AGS will be open at low speed or idle. This thesis focuses on the tradeoff between the aerodynamic performance and the compressor power consumption at high vehicle speeds and mid-ambient conditions (26.7°C and 32.2°C). The results from the steady-state simulations show a tiny reduction in the fuel consumption rate for AGS closed condition by comparing to AGS open condition; while the results for the transient cycle show a remarkable reduction in the fuel consumption rate when the vehicle reaches the highest speed of 128.7 km/h. However, at the low-speed range, there is no benefit in fuel economy with AGS closed, as expected.