The Paccar MX-13 engine, a low-NOx and CARB-compliant engine, is now available for Peterbilt Models 579, 567, and 589.

Peterbilt, Kenworth add Paccar’s low-NOx MX-13 engine to six models

June 13, 2024
Paccar's low NOx MX-13 engine is available in Peterbilt Models 579, 567, and 589 trucks, and Kenworth's T680, T880, and W990 trucks. The engine meets CARB regulations with redesigned internal hardware and aftertreatment system to reduce NOx emissions.

The CARB-compliant, low-nitrogen oxide version of the Paccar MX-13 engine is now available for three heavy-duty Peterbilt and three heavy-duty Kenworth models. The engine meets California Air Resource Board omnibus regulations and features redesigns of internal hardware and the aftertreatment system to reduce NOx emissions effectively.

Peterbilt announced the new MX-13 is available for order in its Models 579, 567, and 589 trucks. Kenworth announced that the new CARB-compliant engine is now available to order on its T680, T880, and W990 trucks.

The larger volume aftertreatment system includes a compact twin assembly featuring a 48-volt generator in the flywheel housing and an electrical heater in the inlet to provide lower NOx output. The internal hardware now features a larger volume mixer, longer selective catalytic converter, and an improved and more durable NOx sensor design with increased longevity for improved uptime. These features allow Peterbilt customers to achieve increased engine efficiency and fuel economy while continuing to meet stringent CARB emissions regulations.

See also: Peterbilt introduces digital vision system-mirrors

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

According to the two truckmakers, both Paccar subsidiaries, the CARB low NOx compliant Paccar MX-13 engine combines its diesel powertrain with next-generation technology. It is available in two ratings with a flat torque curve, providing performance across a wider range of RPMs for excellent drivability and fuel economy. This includes a high-performance 510-horsepower rating with 1,850 lb.-ft. of torque and an efficiency-focused rating of 455 horsepower and 1,650 lb.-ft. of torque between 900 and 1,325 rpm.

“Our customers are looking for better options to successfully navigate the complexities of the evolving regulatory landscape and Kenworth models equipped with PACCAR’s MX-13 CARB-compliant engine achieve compliance with stringent emissions regulations while also delivering a solution that drives increased engine efficiency and enhanced fuel economy,” Kevin Haygood, Kenworth assistant general manager for sales and marketing, said.

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