The Chrysler Group is inspiring itself on human lungs to design the next generation of fuel tanks needed for compressed natural gas (CNG) vehicles.

“Within the human lung are countless individual sacks called alveoli,” says Enrico Pisino, Chrysler Group’s Senior Manager-Innovation. “These sacks combine to expand the lung’s total air capacity. We are using this same approach to improve the packaging of CNG tanks.”

Chrysler Group’s work is supported in part by a $50,000 grant from the Michigan Economic Development Council’s Technology Innovation Challenge, which matches companies with Michigan-based strategic partners to accelerate advanced-technology initiatives.

Chrysler said while CNG has a per-gallon-equivalent cost-advantage of approximately $1 compared with gasoline, its energy density is less by volume. As a result, CNG-powered vehicles require larger fuel tanks to deliver range that is comparable to that of gas- or diesel-powered vehicles.

Current CNG tank designs are currently limited to cylindrical shapes to accommodate the pressure at which the gaseous fuel is stored.

Chrysler Group explained its patent-pending technology addresses both issues by expanding tank capacity and enabling designs that conform to the vehicle, as do other fuel tanks. The benefit is a solution that preserves space intended for passengers and/or cargo.

Chrysler Group already has a CNG vehicle on the market, the Ram 2500 Compressed Natural Gas truck, which the company said is the industry’s only factory-built CNG-powered pickup, rolling off the same assembly line as conventionally powered vehicles

Available for retail and fleet sale, the Ram 2500 Compressed Natural Gas truck features a 5.7-liter HEMI V-8 engine that burns CNG. When that fuel is depleted, it automatically and seamlessly switches to gasoline.

On a single fill-up, the truck can travel 255 miles on CNG and a total of 745 miles when equipped with an available 35-gallon reserve gas tank.