Peterbilt is now offering a CARB low-NOx-compliant Paccar MX-13 engine in its Models 579, 567, and 589.

The new engine features redesigned internal hardware and aftertreatment systems to further reduce NOx.

This was achieved through a compact twin assembly aftertreatment system with greater volume than its predecessor. It features a 48-volt generator in the flywheel housing and an electrical heater in the inlet to provide lower NOx output.

Changes to the internal hardware include a larger volume mixer, longer selective catalytic reduction converter and improved NOx sensor with improved longevity, the company claims.

Peterbilt says not only will emissions be reduced, but fuel economy will be improved.

“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 for our customers,” said Scott Newhouse, Peterbilt chief engineer.

Available for order now, Peterbilt trucks with the new low-NOx engine can be spec’d with 510 hp/1,850 lb.-ft. of torque, or 455 hp/1,650 lb.-ft. of torque.