Who knew Wal-Mart wants to roll forward research on hybrid drivetrains for diesel trucks? We've been following Wal-Mart's forays into biodiesel and hydrogen for a while, but an announcement by ArvinMeritor, Inc. yesterday that they have been tapped by the retailing giant to develop a dual-mode, diesel-electric drivetrain for a Class 8 tractor caught us a little by surprise. Still, it's a very welcome surprise.

ArvinMeritor said this vehicle would likely be the first dual-mode diesel-electric tractor prototype in development in North America. ArvinMeritor will use an International Class 8 ProStar tractor and an engine developed by Cummins Inc. as the basis for the prototype. ArvinMeritor will use someone else's batteries for the hybrid (Who? They're not saying), but will provide the regenerative braking system and electronic controls, among other things. The electric motor will move the truck during "periods of high demand under low-speed, high-load operating conditions, such as accelerating from a stop," and the diesel engine kicks in at highway speeds. In between, well, it's a hybrid, so both will contribute. The electric motor can also assist when needed, such as when traveling up a hill.

Even though Wal-Mart announced a while ago it wants to double the fuel efficiency of its heavy-duty truck fleet in 10 yeas, the company does have some cleaning up to do. In late 2005, Wal-Mart settled a lawsuit with the EPA for clean air violations by taking part in an anti-idling campaign at its 4,000 locations across the country.

Detail junkies, click through the jump for the full press release from ArvinMeritor.

Related:

• Hydrogen powered electric lift-trucks pass Wal-Mart tests
• Wal-Mart has been out searching for biodiesel provider longer than we knew

[Source: ArvinMeritor, Inc.]