The Army is currently working on two new prototype Humvees, with the goal of dramatically reducing the amount of fuel they use while still providing the same protection that the current fleet of up-armored Humvees have. (The technically correct name of a Humvee is actually HMMWV, or High Mobility Multipurpose Wheeled Vehicle).
The first new model, dubbed the FED Alpha (Fuel Efficient Ground Vehicle Demonstrator), is not really a hybrid, but has a solar panel on the rear hatch to recharge its electrical systems, in addition to lots of other improvements to reduce the amount of fuel used compared to the current version of the Humvee that’s actually in use today. It’s built around an aluminum frame (except for the armored cab and the v-shaped blast shield covering the bottom of the vehicle. It uses a much more up to date Cummins turbo-charged 200 horsepower 4 cylinder diesel engine with a 6 speed automatic transmission (compared to a 3 speed on the current version of the Humvee), coupled with low rolling resistance tires. The tires themselves decrease fuel consumption by 7 percent. The FED Alpha also uses a custom differential with non-geared hubs in order to reduce friction.
The other new version is being called the FED Bravo, but details surrounding the FED Bravo are currently classified, so not much is known. What is known is that it will be a plug-in hybrid similar to the Chevy Volt. They’re calling it a “road coupled parallel hybrid” – the front axle runs off of electrical motors, while the rear axle is powered by both the diesel engine and the hybrid system. The Army is hoping that the Bravo model will be 70 percent more efficient than their current Humvees.