BENTONVILLE, AR – Wal-Mart Stores Inc. is teaming up with ArvinMeritor, an auto component supplier, to develop a diesel-electric hybrid truck that may be the first of its kind in North America, according to theMorning News newspaper. The companies said in a news release last week that they had agreed to develop a dual-mode, diesel-electric drivetrain for a class 8 truck, called the “workhorse of the U.S. long-distance trucking industry” by ArvinMeritor. The hybrid would offer zero emissions and fossil fuel consumption.

“We’ve been working on development of hybrid drivetrains for some time,” said Carsten Reinhardt, president of ArvinMeritor’s Commercial Vehicle Systems business, in the news release. “This class 8 project is a major step in our continuing work in alternative drivetrain development — both for power transmission and emissions — and holds tremendous promise for the worldwide heavy-duty trucking market in a number of important environmental and economic ways.”

Wal-Mart President and CEO Lee Scott said last year that doubling the fuel efficiency of the company’s fleet of trucks was part of the company’s new environmental program. Wal-Mart spokesman Dave Tovar said that the company is hoping the hybrid truck will help achieve that goal. He also said that the project will take “some time,” and that there will be commercial applications for the hybrid truck beyond use by Wal-Mart.

Wal-Mart has 7,000 trucks in its fleet.

Dual-mode diesel-electric drivetrains use the electric motor drive primarily for periods of high demand under low-speed, high-load operating conditions, such as accelerating from a stop, the release said. 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.