Low NOx CARB-compliant MX-13 engine variant from Peterbilt

Model 579 with the low NOx Paccar MX-13 engine (Photo: Peterbilt)

Peterbilt has added a new CARB-compliant (California Air Resources Board) low nitrogen oxide (NOx) versions of the MX-13 engine to the Model 579, 567 and 589 trucks.

With a series of updated hardware and aftertreatment components, the engine meets CARB Omnibus regulations.

The aftertreatment system features a compact twin assembly which includes a 48 V generator located in the flywheel housing. Additionally, there is an electric heater on the inlet, which helps to reduce NOx emissions.

Internal hardware includes a larger-volume mixer, longer selective catalytic converter (SCR) and a more durable NOx sensor to deliver improved longevity.

The MX-13 engine is available in two ratings, with a flat torque curve providing performance across a wide range of engine speeds. Peak output is 510 hp and 1850 lb ft of torque. To achieve improved economy, between 900 and 1325 rpm the engine still produces 455 hp and 1650 lb ft of torque.

“Paccar MX engines were engineered for reliability and fuel economy in a comfortable, quiet and powerful package. The new CARB low NOx Paccar MX-13 engine offers the same great features with a reduced carbon footprint,” said Scott Newhouse, Peterbilt chief engineer.