Catalyst Spring 2015

[HOW IT WORKS]

Fuel-Efficient Trucks

Many existing fuel-saving technologies could dramatically increase the fuel efficiency of America’s heavy-duty vehicles—cutting oil use and global warming emissions in the process. New standards proposed by the Environmental Protection Agency would help advance the adoption of these technologies across today’s trucking fleets. Here are some of the key changes that, together, can add up to big savings.

Aerodynamics

Rolling resistance:Reducing the weight and rolling resistance (i.e., the friction between the rolling tire and ground) of trailers through more efficient tire and axle design helps reduce the amount of fuel needed to pull freight.

Trailer skirts: Pockets of air turbulence develop beneath trailers, increasing drag. The addition of a “trailer skirt” can improve a tractor-trailer’s fuel efficiency as much as 5 percent by reducing drag under the trailer and pushing the air around the trailer wheels.

Boat-tails: This aerodynamic equipment fitted to the back of a trailer can add additional fuel savings by reducing turbulence in the wake of air behind the vehicle. Undertrays and rear fairings—such as those you see on Formula One race cars—also direct air flow.

Electricity

Battery-powered accessories and equipment: Accessories such as air conditioning and external equipment such as lifts and refrigeration units often run on diesel generators or power from a truck’s engine. Converting the power source for these accessories and equipment to battery power can save fuel by avoiding the need for truckers to idle their engines while parked.

Hybrid-electric trucks: These vehicles increase fuel efficiency by combining a conventional internal-combustion engine with an electric motor, batteries, and braking-energy capture (known as regenerative braking).

Fuel cell electric trucks: These vehicles are powered by fuel cells, which convert hydrogen and air into electricity while emitting only water vapor.

Battery-electric trucks: With no internal combustion engine, these vehicles are instead propelled by an electric motor powered by onboard batteries. The range of a current battery-electric truck varies from 50 to 100 miles per charge.

Engine Adjustments

Transmissions: Improvements in transmissions that reduce friction and keep the engine operating at maximum efficiency can improve the fuel consumption of all trucks.

Heat exhaust recycling: Heat from the engine is usually wasted as exhaust, but could be captured and used to improve the engine’s power output.