Automotive Air Condition System Performance Test
1.Description
For cooling performance of the A/C, measure the difference of temperature between the inlet port and outlet port of the air, and judge whether the value is within the standard range in the standard performance chart.
2.Test condition
Test the vehicle in the following conditions:
Stopping condition in shade
Engine coolant temperature: After warm-up
All doors: Fully open
Airflow selector: “FACE”
Air inlet selector: “RECIRC”
Engine speed: 1,500 rpm (R-134a), 2,000 rpm (R-12)
Blower speed: HI
Temperature selector: MAX.COOL
A/C Switch: ON
Pressure on the high-pressure side: 1.5MPa (15.5 kgf/cm²)
3.Measure each temperature
Place a dry and wet bulb thermometer at the air inlet and a dry bulb thermometer at the center of the outlet port. When the air temperature at the outlet stabilizes (after approximately 5 to 6 minutes), measure the difference between both dry bulb thermometers and the relative humidity of the air at the air inlet port.
4.How to obtain relative humidity
Apply the temperature of the dry bulb thermometer and of the wet bulb thermometer at the inlet to the psychrometric chart to obtain the relative humidity. For example, when the dry-bulb thermometer is 25°C (77°F) and the wet-bulb thermometer is 19.5°C (67.1°F), the point at which the lines cross is the relative humidity. In this case, it is 60%.
5.How to read performance chart
If the intersection point made by the crossing of both values is within the shaded area, this cooling ability can be judged good.
