For regional haul and vocational fleets operating Class 5, 6 and 7 medium-duty trucks, natural gas is growing as a power source of choice. Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG) have gained a great deal of attention for several reasons. One of those is the ready availability of domestically produced natural gas at a time when reserves of oil are diminishing, along with new techniques that allow companies to recover the ample supply of natural gas in North America.

Also driving interest in this fuel source are environmental benefits. Burning methane, the largest element in natural gas, results in significantly fewer harmful emissions than gasoline or diesel. Commercially available medium- and heavy-duty natural gas engines have demonstrated over 90% reductions of carbon monoxide (CO) and particulate matter and more than a 50% reduction in nitrogen oxides (NOx) compared to diesel engines.

Another widely touted potential benefit of natural gas is lower long-term operating costs when compared to diesel or gasoline. Although initial acquisition costs are still higher for natural gas engines, lower fuel costs and anticipated payback over the average vehicle lifecycle have been shown to easily make up the difference, producing savings.

Adding further to the attraction of natural gas truck engines are government incentives. Factored into the cost equation, these make the financial argument for natural gas vehicles stronger.

Congress, for example, is developing purchase incentives to encourage the transition to alternative fuels such as CNG and LNG. These incentives may also extend to the refueling infrastructure used by fleets. A readily available database of federal and state laws and incentives related to alternative fuels and vehicles can be found at www.afdc.energy.gov/afdc/laws.

In preparation of meeting increasing market demand, Navistar is in the process of developing a product strategy that will make available natural gas powered International medium-duty trucks. The OEM is currently working to define the requirements of an Environmental Protection Agency compliant dual fuel engine and expects to have built and tested the first concept unit by this month.

During the 2010 Electric Utility Fleet Managers Conference held in June (www.eufmc.com), Navistar demonstrated a natural gas-powered medium-duty vehicle featuring a MaxxForce DT-466 conversion kit developed by Emissions Solutions Inc. (ESI) The manufacturer’s engine technology includes the ESI Phoenix NG 7.6L dedicated natural gas engine that utilizes a diesel engine as its base platform.

Available using CNG or LNG as its fuel source, the Phoenix NG 7.6L operates as a Stoichiometric Spark-Ignited internal combustion engine and incorporates an Electronic Control Unit (ECU) and a fly-by-wire electronic throttle body for improved performance and durability. Weighing in at 1,197 lbs., the 7.6-liter powerplant is rated 265 HP at 1,917 RPM and 820 ft./lb. of torque at 1,347 RPM.

For Navistar, the ability to offer a clean-burning natural gas engine with the power and torque required by a wide range of medium-duty truck operations is a reflection of the company’s desire to anticipate and meet changing industry demands.

“There are a growing number of customers interested in natural gas vehicles,” noted Jim Hebe, senior vice president, North American sales operations, Navistar. “Municipalities, as well as any businesses with vehicles that go back to a home-base every night, are ideal candidates for natural gas.”