Aerodynamic device testing

Michelin's Laurens Proving Ground is a 3,300 acre facility comprised of 12 tracks and testing areas, with tracks comprised of asphalt, concrete, gravel, and dirt. SmartTruck conducted its "coast down" testing on Track 9; a 1 mile straightaway with a 1.5% grade bookended by two return loops.

SmartTruck used a 2000 model Freightliner Century Class tractor equipped with a 10-speed Fuller manual transmission and 475 hp Detroit Series 60 engine hooked to a 53-foot Hyundai dry van trailer to conduct its "coast down" testing demonstration.

SmartTruck equipped the upper sides at the rear of the Hyundai trailer with its side fairing system.

Tucked in behind the underride guard at the rear of the trailer is SmartTruck's "diffuser" unit which helps rechannel airflow to eliminate low pressure drag "pockets" created at the rear of the vehicle at highway speeds.

The main component of SmartTruck's trailer aerodynamic system is the "undertray" unit seen here.

A special "fifth wheel" is used to record more detailed and precise rolling resistance data during the low speed deceleration portion of the "coast down" test.

Several devices mounted to the top of the tractor's cab measure wind speed and wind direction, which can affects the aerodynamic performance of the vehicle, along with air density.

Sensors mounted within the engine compartment measure the impact of clutch fan activation and steering wheel position on the aerodynamic profile of the vehicle; especially in terms of the impact on rolling resistance from the tires.

A close up of the sensor array under the hood.

Data from all the various sensors on the vehicles, along with information from the vehicle's electronic control module (ECM) governing the engine, are relayed to SmartTruck's test engineers via a wireless computer modem tucked inside the tractor's sleeper berth.