The Ram’s 5.7-liter HEMI bi-fuel engine has been modified to run on compressed natural gas as well as gasoline. Redesigned cylinder heads with specifically designed CNG compatible valves and valve-seat materials allow the engine to burn both fuels. It also gets a second, CNG-specific fuel rail and set of injectors. New spark plugs improve combustion and durability, and a new powertrain control module allows the HEMI to seamlessly operate on either of the two fuel sources.

The Ram 2500 CNG system was fully engineered and tested by Chrysler Group and assembled at the company’s Heavy Duty truck plant in Saltillo, Mexico.

In use, the system is automatic; eliminating operator switches altogether and utilizes either CNG or gasoline, transitioning from one to the other with little discernible difference in operation or capability.

Although a small amount of gasoline is used during engine startup, the Ram CNG runs exclusively on compressed natural gas. If the CNG tanks are emptied, the vehicle will automatically switch to gasoline.

In addition to a conventional gasoline fuel gauge, a second CNG-specific gauge sits adjacent to it in the instrument cluster.

CNG-only range is estimated to be 255 miles, while the backup supply of gasoline extends the range to 367 total miles.

The Ram 2500 Heavy Duty CNG’s two 4.6 cu.-ft. (130-liter) CNG tanks are located in the forward portion of the Ram’s 8-foot pickup bed. Both tanks are mounted to the frame and covered by a painted 50 ksi high-strength steel cover. The CNG filler connection is located next to the gasoline fuel neck, accessed through the Ram’s fuel filler door. The CNG tanks provide a gasoline gallon equivalent (GGE) of 18.2 gallons.

Ram 2500 CNG offers 1,580 lbs. of payload, 4-ft.-8-in. usable bed length and 7,650 lbs. of towing capability. The Ram 2500 is delivered ready-to-tow and standard equipment includes the integrated 4- and 7-pin connectors along with a Class IV hitch receiver. The Ram CNG also comes with a trailer brake controller with customer-programmable electric or electric-over-hydraulic trailer brake options.

A 5-year/100,000-mile powertrain limited warranty covers the HEMI V-8 and transmission, and adds internal engine components specific to CNG: the upgraded valves, the valve seats, fuel injectors and rail and the specially designed spark plugs—all part of the factory installed manufacturing and production processes.

Covering virtually every other aspect of the Ram 2500 CNG is a 3-year/36,000-mile bumper-to-bumper limited warranty. Specific to the CNG engineering, this covers all non-engine components, including the tanks, storage compartment and fuel filler equipment.

Chrysler parent Fiat is the dominant CNG manufacturer in Europe with a greater than 80% share of the market. Fiat sales of compressed natural gas vehicles in Europe have exceeded 480,000 passenger cars and light duty vehicles (1997-2011).

Moreover, since 1995, Iveco (Fiat Industrial’s truck and commercial vehicles division) has focused heavily on natural gas propulsion, and is now European leader in research and sale of natural gas vehicles, with 11,000 units now in use by private companies and public authorities.

Italy has more widely adopted CNG vehicles than the US and offers 800 public CNG stations.