Peterbilt Motors Co. says it intends to offer the new Cummins Westport ISX12 G natural gas engine as an option in 2013. The company already equips its vehicles with the Cummins Westport 8.9-liter ISL G and Westport HD 15-liter engine.

The 11.9-liter ISX12 G will be configurable to either compressed natural gas (CNG) or liquefied natural gas (LNG) and be available in five power/torque ratings, from 320 hp/1,150 lb.-ft. to 400 hp/1,450 lb.-ft. These six-cylinder, spark-ignited engines are tailored for tractors in the regional-haul, vocational and refuse sectors.

Peterbilt notes that it has been manufacturing trucks featuring LNG and CNG fuel systems since 1996. In that time, the company has captured 40% market share of the commercial truck natural gas market, Peterbilt says.