Shed a few joules with better aerodynamics

A team of engineering students from Laval University has managed to reduce the energy demand due to wind resistance of its Supermileage vehicle by 10% after carefully designing a new vehicle body with a 25% larger frontal area.

THE SUPERMILEAGE TEAM AT LAVAL University is constantly working to improve the fuel efficiency of its gasoline-powered, one-person vehicle. Its vehicle is called the Alérion and its power plant is a customized 56.5 cc fuel-injected four-stroke engine. It has three wheels: two in front that steer and one at the rear that drives. The car currently holds the North American record for fuel consumption at 1347 km/L, as registered at the Eaton proving grounds during the 2008 Supermileage competition. Although successful, the body of the car was getting old, and the team took this opportunity to design a new carbon fiber shell by carefully studying its aerodynamic performance. New design constraints made it quite a challenge to reduce the overall aerodynamic drag forces.

Amongst these new constraints was the use of Michelin 45/75R16 tires. They are considerably wider, but have a significantly lower rolling resistance, and thus increase the fuel efficiency of the vehicle. The two front wheels are now protected by carbon fiber internal covers. Moreover, the camber angle, or the angle formed by the wheel vertical axis and the ground normal direction, was reduced from 8° to 1.2° to reduce the rolling resistance. Because there is no frame other than the carbon fiber shell, a honeycomb underbody rigidifies the shell to prevent a misalignment of the front wheels caused by the bending of the vehicle. Accommodating these new requirements increases the frontal area by 25%.