Kenworth Updates MX Engines, Teases New Medium-Duty Truck

Kenworth told Work Truck Week attendees that it has enhanced its MX engines for 2021, improving fuel economy and durability – and teased a new medium-duty truck to be introduced soon.

In a virtual chassis update March 11, Brandon Singh, vocational marketing manager, highlighted some of the changes to the new Next Generation T680 introduced recently, as well as some features that will be appearing on Kenworth’s other heavy-duty models, including the new 15-inch digital display, an updated smartwheel (which has programmable telltales for vocational customers), and new cab interior colors.

But he spent the most time on highlighting the enhanced MX-11 and MX-13 engines, which of course are also available in Peterbilt trucks.

Changes to the base engine, diagnostics, and emissions resulted in several enhancements and technological advantages – including an up to 2.5% fuel economy improvement over the EPA-2017 models.

Paccar enhanced its performance and durability testing, including increasing its test hours from 4,000 to 8,000 – the equivalent of 1 million-plus miles, Singh said.

Some of the enhancements that have improved reliability, fuel efficiency, and emissions include:

• structural enhancements such as cylinder block updates, an improved crankshaft design, and camshaft and engine brake redesign that increases oil flow.

• an updated piston design with optimized bowl geometry that has improved fuel economy, decreased emissions, and reduced oil consumption.

• a new engine harness with reduced complexity and fewer connectors to help protect against the elements

• a brand-new, Paccar-designed on-engine fuel module that offers better cold-weather performance, speedier installation and changeout times. This module allows multi-pulse fuel injection to help improve fuel economy.

• upgraded emissions sensors that will perform better in inclement weather

• updated turbocharger that is smaller and more efficient for improved responsiveness and reduced combustion noise.

There are some new ratings for 2021. A new 445 hp, 1,700 lb.-ft @ 900 rpm for the MX-11 “offers increased power-to-weight ratio, maximizing performance and load hauling capacity,” he said.

On the MX-13, there’s a new 485 hp rating with 1,650 lb.-ft @ 900 rpm, which is a lower rpm than previously available. In addition, there’s a new multi-torque rating, 405 hp, 1,650/1,750 at 900 rpm.

The MX-13 offers increased downspeeding; it’s now capable of cruising at 1,050 rpm with a 2.47 rear axle ratio in Kenworth aero models such as the Next Generation T680.

Kenworth’s medium-duty update from J.T. Mansurov, medium-duty marketing manager, consisted of a video teasing the upcoming announcement of a new medium-duty Kenworth.