6. Dynamometers

The dynamometer provides variable resistance to the vehicle to simulate the effects of loads and inclines.  For cars and trucks up to 400 hp (298 kW) at the drive wheels, the chassis roll dynamometer is used.  The 6 ft (1.8 m) diameter rolls, capable of speeds up to 100 mph (161 km/hr), are moveable to permit testing FWD and RWD vehicles over a wide range of wheelbases.  The dynamometer rolls can also be raised, allowing tandem-axle trucks to straddle the rolls.

For trucks that exceed 400 hp (298 kW) at the drive wheels, a 1000 hp (746 kW) water-brake dynamometer is available. It mounts to the vehicle frame and couples directly to the driveshaft.

Stationary turning vanes
Airflow settling screens
Airflow nozzles
Fan
Chassis roll dynamometer
Main heat exchanger
Humidifier (steam distribution grid)
Hinged turning vanes
Vehicle entrance

7. Wind

A 600 hp (447 kW), 11 ft (3.4 m) diameter vane-axial fan generates wind speeds up to 100 mph (161 km/hr) in the closed horizontal air path.

Turning vanes and settling screens provide uniform airflow velocity (within 2%) across the test section.  The airflow nozzle converts from 55 to 110 ft²(5.25 to 10.5m²), to accommodate both passenger cars and large trucks or buses.

8. Solar Simulation

High-quality solar simulation is provided by an overhead array of 66 high-intensity Tungsten Halogen lamps, mounted at a compound angle to duplicate the severity of mid-afternoon sun streaming in the windshield and driver-side windows.

The lamps are individually selectable, giving full control over pattern and intensity up to 320 BTU/hr ft² over 160 ft² (1 kW per m² over 15 m²).

The air temperature in the wind tunnel can be controlled within 1 °F over a range of -40 to 120 °F (-40 to 50 °C).  Temperature changes can be accomplished at the rate of 10 °F (5.5 °C) per hour.  Humidity can be precisely controlled over a range of 10% to 95% RH by injecting steam or by drying the make-up air.