The US Defense Department is considering a hybrid replacement for the Humvee for the US Marine Corps. The new model, called the Shadow RST-V, uses a diesel-hybrid configuration.

It uses less than 50 percent of the fuel weight of the present Humvee. The vehicle can operate in electric only mode for about 20 miles, giving it very stealthy characteristics. In electric mode, it's not only very quiet, but generates much less heat than a vehicle using a regular engine.

The RST-V uses 440 pounds of fuel per month during extended reconnaissance missions, compared to 1,040 for a Humvee.

The vehicle's diesel generator is a turbocharged, 2.5 liter four cylinder producing 138 HP.

Each of the four wheels has a motor powered by lithium ion batteries. Consumer hybrid vehicles currently use nickel metal hydride batteries , which have a lower power density than Li-Ion batteries. It will be interesting to see if and when hybrid cars switch to the superior Li-Ion battery design. Also, having electric motors at each wheel is a design that would seem suitable for 4WD SUVs. The motor in each wheel design is one that's been developed to retrofit transit buses in Europe to make them hybrids.