LOUISVILLE, KY - At this week's Mid-America Trucking Show in Louisville, Navistar demonstrated a prototype 2011 International ProStar+ powered by a 13-liter MaxxForce dual fuel engine -- diesel and liquefied natural gas.


"Recognizing the abundant supply of natural gas in the United States and Canada, we feel compelled to invest in our products in such a way that enables our customers to expand their usage of very low emissions technologies through our engines," said Jim Hebe, senior vice president, North American sales operations, Navistar. "The use of natural gas certainly accomplishes this and we are proud to be developing the broadest, most energy-efficient line of trucks in the industry, helping deliver real-world savings to the bottom line."

In partnership with Clean Air Power Ltd., Navistar has built and tested a 2011 International ProStar+ 122-inch BBC tractor with a 430-horsepower, 1,550-pounds-foot dual fuel MaxxForce 13-liter engine. The engine uses diesel pilot injection for combustion on the compression stroke and mixes air and LNG on the intake stroke. The result is an engine that runs on a mixture of 15 percent diesel and 85 percent natural gas.

The dual fuel 13-liter MaxxForce engine includes minimal changes to the stock diesel engine other than the addition of a natural gas injection system. Changes to the chassis include the addition of a 26-inch diameter, 119-gallon standard LNG tank that provides a 400-mile range, a coolant heated fuel vaporizer, and an LNG regulator and filter. Navistar is currently working with the EPA to define the regulatory requirements of an EPA compliant dual fuel engine.

"As we assess changing market conditions, the ability to offer customers choice is important not only in our U.S. markets, but in our global markets as well," Hebe added. "As we develop this product for our International truck customers, we will also be able to leverage the technology in other markets and products as appropriate."

BNavistar has also recently demonstrated compressed natural gas (CNG) versions of its DuraStar and WorkStar trucks.