Performance Enhancement of Mobile Air Conditioning System With Improved Air Management for Front End

The current investigation is focused on enhancing the mobile air conditioning performance by improving the air management for the front end. The following enhancing strategies were investigated: air guides, seals between the condenser and radiator and the seals on the hood. The following are the major conclusions from this study: A study of 12 current production vehicles revealed that the majority of the vehicles did not have good front end designs for optimum performance. Significant amount of air bypasses the condenser and radiator in the current production vehicles that has a major impact on the performance of the air conditioning and engine cooling systems. For a typical current production vehicle 15% bypassed the condenser; 24% bypassed the radiator; and 9% bypassed between the condenser and the radiator. This is the first paper in the literature that presents this information. Wind tunnel data indicated significant improvements in the vent outlet temperatures (1∼3.5 °C); cabin temperatures (1∼3 °C); and a reduction in the head pressures (2.1∼5.4 kg/cm² or 30∼77 psi). Recirculation of the hot engine compartment air was reduced from 29 °C over the ambient (base case) to approximately 15 °C over the ambient. Finally, flow visualization methodology was developed with the help of a smoke gun to analyze the front end of the vehicle..

The results from this investigation can be used as a design tools in computing the AC system performance at idle by taking the percentages of the bypass airflow to condenser and or radiator into account for the calculations for the front end. Analysis from this investigation can also be used in designing better front end of the vehicles to improve air management to enhance performance of the air conditioning systems and gas mileage.