Cummins Inc. has begun development of a 15-liter heavy-duty, spark-ignited natural gas engine for on-highway applications.

The announcement was made at the Mid-America Trucking Show in Louisville today, and builds on the recent decision to produce a factory-built, dedicated natural gas version of the 12-liter ISX engine, the ISX12.

As natural gas production grows in North America and the fuel becomes more readily available, Cummins believes that there is a strong market for engines powered by an alternative to diesel fuel.

"Cummins is committed to making the right investments in the technologies that strengthen our leadership position in natural gas," says Cummins Vice President and General Manager of Heavy-Duty Engine Business, Ed Pence.

The ISX15 G will be based on the ISX15 diesel engine and will build on Cummins technology leadership with spark-ignited, Stoichiometric cooled Exhaust Gas Recirculation technology. A simple, maintenance-free Three-Way Catalyst will be the only required exhaust aftertreatment. The engine will run on compressed natural gas, liquefied natural gas or biomethane. Cummins expects the ISX15 G to be in limited production by 2014.

The Cummins Westport ISX12 G will be officially unveiled in the Cummins booth at the Mid-America Trucking Show in Louisville on March 22, 2012.

The ISX12 G natural gas engine is based on the Cummins ISX12 diesel engine platform, the newest member of Cummins Heavy-Duty engine family. The ISX12 G will operate exclusively on natural gas, and fuel can be carried on the vehicle as either compressed natural gas (CNG) or liquefied natural gas (LNG), utilizing Cummins Westport's proprietary spark-ignited, Stoichiometric cooled Exhaust Gas Recirculation technology, first introduced with the 8.9-liter ISL G.

The ISX12 G also features Three-Way Catalyst aftertreatment, which is packaged as a muffler and is maintenance-free. No Diesel Particulate Filter or Selective Catalytic Reduction aftertreatment will be required.

A range of five ratings, from 330 hp to 400 hp and 1,150 to 1,450 lb-ft torque will be offered at launch. Field-testing is under way, with production expected to begin in early 2013. The ISX12 G will also be the first engine from Cummins Westport to offer optional engine brake capability and will also offer customers the choice between manual and automatic transmissions. Formerly, natural gas engines had to be mated with automatic transmissions.

The ISX12 G will be manufactured a the Cummins Heavy-Duty Engine Plant in Jamestown, N.Y., and will be backed by a Cummins base warranty (2 years, 250,000 miles; 6,250 hours of operation). Extended coverage options will be released closer to production. Service, parts and training support will be delivered by the Cummins service network.

"This is an important product development for Cummins Westport, given the increasing demand for natural gas vehicles in the heavy-duty market," said Jim Arthurs, President of Cummins Westport. "The ISX12 G will offer customers heavy-duty performance, reliability and durability and a choice of either compressed natural gas or liquefied natural gas as a fuel."

The ISX12 G target markets at launch are North American regional-haul and vocational truck/tractor, and refuse applications, where demand for natural gas vehicles is growing. Anticipated end-use applications in the regional-haul market segment include intermodal and distribution operation and pickup-and-delivery. Potential postlaunch market opportunities include motorcoach and specialty vocational applications.

The ISX12 G is expected to be certified at launch to meet the U.S. Environmental Protection Agency (EPA) and California Air Resources Board (ARB) emissions standards of 0.20-g/bhp-hr oxides of nitrogen (NOx) and 0.01-g/bhp-hr Particulate Matter (PM). The engine is additionally expected to be capable of meeting Euro VI and pending U.S. greenhouse gas and fuel economy regulations.

Partial funding in support of the ISX12 G engine development has been received from the U.S. Department of Energy's National Renewable Energy Laboratory (NREL), in partnership with the California Energy Commission and the South Coast Air Quality Management District, and the California Energy Commission in conjunction with the Gas Technology Institute.

Cummins has been investing significantly in the development of natural gas engines. In addition to its off-highway natural gas engines, Cummins is already producing on-highway spark-ignited natural gas engines for Cummins Westport, its joint venture with Westport Innovations in Vancouver, British Columbia.