Cummins Westport ISX12N

The Cummins Westport ISX12N is an 11.9-litre, six-cylinder inline natural gas engine for motorcoach, regional haul truck/tractor, vocational and refuse applications. The engine is compatible with compressed natural gas (CNG), liquified natural gas (LNG), and renewable natural gas (RNG). The engine was announced in May 2017 and replaced the Cummins Westport ISX12 G in 2018.

The ISX12N uses a three-way catalyst which works by introducing a catalyst to convert the nitrogen oxides to nitrogen gas and oxygen gas, carbon monoxide to carbon dioxide, and hydrocarbons to carbon dioxide and water. The engine also features cooled exhuast gas recirculation (EGR) and spark-ignited stoichiometric combustion. Crankcase emissions are captured and rerouted back to the engine. A new engine control module offers faster processing and is telematics capable. The 2018 ISX12N is certified to CARB optional low NOx emissions standards of 0.02 g/bhp-hr, 90% lower than the previous standards.