By now, it’s apparent that hybrid technology is emerging as a significant force in the war on fuel consumption. There now are several players, and probably more to come. Here’s the latest:

ArvinMeritor and Wal-Mart Transportation have agreed to develop a dual-mode, diesel-electric drivetrain for a Class 8 tractor. The vehicle will be based on an International ProStar tractor with a Cummins engine.

ArvinMeritor will provide the tandem axle, regenerative braking system, air disc brakes and advanced ABS with integrated stability control and driver assistance systems.

Wal-Mart has said that, within the next 10 years, it intends to double the fuel efficiency for its fleet of heavy-duty trucks. Dual-mode diesel-electric drivetrains, which have both mechanical and electrical propulsion systems, use the electric motor drive primarily for periods of high demand under low-speed, high-load operating conditions, such as accelerating from a stop. 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.

In addition to its work at highway speeds, the engine also charges the batteries. Energy generated during braking also is captured and routed to the batteries.

In other news, the U.S. Environmental Protection Agency recently unveiled a series hydraulic hybrid diesel urban delivery vehicle, a result of a partnership between the EPA, U.S. Army, UPS, International Truck and Engine Corp. and Eaton Corp.

The EPA and UPS plan to evaluate the vehicle’s fuel economy performance and emissions during a series of tests. In laboratory testing, the EPA’s patented hydraulic hybrid diesel technology achieved a 60 to 70 percent improvement in fuel economy and more than a 40 percent reduction in carbon dioxide emissions, compared to a conventional UPS vehicle.