Class 8 trucks have a Gross Vehicle Weight Rating (GVWR) of 33,001 pounds or more, three axles and 10 tires. Vehicles that fall under this rating include tractor-trailers (50'), moving trucks, freight trucks, concrete trucks, gravel trucks and articulated buses. Wal-Mart uses Class 8 trucks to haul its trailers and deliver product to its stores.

ArvinMeritor Dual-Mode Hybrid Propulsion. Wal-Mart will test this diesel-electric hybrid in the Detroit area. The ArvinMeritor hybrid has both mechanical and electrical propulsion systems (dual mode), which use the electric motor drive primarily for periods of high demand under low-speed, high-load operating conditions, such as accelerating from a stop. (Earlier post.)

Once moving, the mechanical propulsion system begins to blend its power with the electric motor until it reaches highway speeds, where the drive phases to completely mechanical. The electrical system can provide additional power during hill climbing, even at highway speeds.

In addition to its work at highway speeds, the engine also charges an onboard energy storage system, which provides power to the electric motor when demand is high. Energy that is generated during braking is captured and stored using regenerative braking.

This technology could help Wal-Mart increase its fleet efficiency by up to 25%.

Peterbilt/Eaton Hybrid Assist. The Eaton heavy-duty hybrid system with idle reduction features an automated manual transmission with a parallel-type direct hybrid system, incorporating a 44 kW electric motor/generator located between the output of an automated clutch and the input to Eaton’s Fuller UltraShift transmission. (Earlier post.)

The Peterbilt/Eaton hybrid provides electric power to assist the engine and also serves as the Auxiliary Power Unit (APU), delivering a significant reduction in engine idling. The electric motor kicks in when the truck needs extra power, such as accelerating from a stop or when going uphill.

The five Peterbilt Model 386 heavy duty diesel-electric hybrids are being tested in Dallas, Houston, Atlanta, Southern California and the Baltimore/Washington DC region. This technology could help Wal-Mart increase its fleet efficiency by up to seven percent.

Reclaimed Grease Fuel and Biodiesel. Wal-Mart will test 15 Class 8 trucks retrofitted by Environmental Development Group to run on Reclaimed Grease Fuel made of waste brown cooking grease from Wal-Mart stores. This partnership provides Wal-Mart the opportunity to develop a closed loop solution for the waste cooking grease it generates in its stores and Sam’s Club locations. This technology could help Wal-Mart increase its fleet efficiency by up to two percent. In addition, the remaining trucks located in the Buckeye, Ariz. distribution center will operate on an 80/20 blend of biodiesel made of waste yellow cooking oil.

LNG. In partnership with Mojave Air Quality Management District, Wal-Mart will test five trucks (four Class 8 and one yard truck) equipped with Westport Innovations’s HPDI LNG system and Cummins ISX engines operating on liquefied natural gas (LNG). (Earlier post.)

Wal-Mart achieved more than a 25% increase in efficiency within its private fleet between 2005 and 2008, surpassing one of the company’s stated sustainability goals. This goal was reached by using a combination of new, innovative technologies, better delivery routes and by loading its trailers more efficiently. Now, the company is working toward its goal of doubling its fleet efficiency by 2015, from its 2005 baseline. Part of this pilot program is to determine if alternatively fueled trucks can help move Wal-Mart toward that goal in addition to reducing environmental impacts.

Wal-Mart will test these new technologies throughout 2009.