Navistar’s new internal combustion engine will be its last

LAS VEGAS — Navistar Inc.’s S13 integrated powertrain for its on-road trucks is the manufacturer’s latest new internal combustion engine. It’s the strongest signal yet that mainstream truck manufacturers are embracing zero-emission electric trucks.

Combined with aerodynamic styling, the new powertrain that will go into production in July 2023 offers up to 15% more energy efficiency than the current A26 engine and Eaton Cummins Endurant transmission from Navistar’s on-road flagship International LT. The new engine’s emissions profile is pending certification.

The S13 represents the North American result of five years of global collaboration between Navistar and parent company Traton Group. Traton developed the base engine at its Swedish subsidiary Scania two years ago.

“Scania has been a good teacher,” Navistar chief operating officer Michael Grahe said during a presentation of the new powertrain to dealers, customers and the media at Las Vegas International Speedway on Tuesday.


Watch now: Navistar’s revamped LT hits the Las Vegas runway


The S13 is built at Navistar’s engine plant in Huntsville, Alabama, where Navistar invested $190 million for the new engine and key components.

When mated to Navistar’s T14 transmission – the company’s first in-house developed transmission – the integrated powertrain takes a significant step towards Navistar’s goal of selling 50% zero-emission vehicles by 2030, increasing to 100% by 2040.

An electric future but a long way for diesel

“Obviously, with Navistar’s product lineup, mid-duty electric trucks will make up the bulk of the 2030 number,” Navistar CEO Mathias Carlbaum told FreightWaves on the sidelines of the launch event. “But we’ve said before that when the industry is ready for long-haul electric trucks, we’ll be there.”

During the reveal program, electric trucks were barely mentioned. However, Mark Hernandez, Navistar’s executive vice president of manufacturing, told FreightWaves that an RH International Class 8 battery-electric truck for regional haul will be built at Navistar’s new assembly plant in San Antonio.

Navistar is expected to officially introduce the battery-electric RH next year. He quietly showed off a prototype at the Advanced Clean Transportation Expo in May.

Despite supply chain disruptions, Navistar produced 50 medium-duty eMV trucks a day in late July in San Antonio, Hernandez said. The target was 52 trucks per day.

S13 could save $31,000 in fuel over 5 years

Presentations on the S13’s modular approach – which will replace Navistar’s A26 engine introduced in 2017 – explained how Traton and Navistar took a clean sheet approach in a powertrain alliance formed when Traton’s parent company, Volkswagen AG , acquired its initial stake in Navistar in September 2016.

Traton spun off from VW as a truck holding company in 2018. It paid $3.7 billion for the remainder of Navistar in July 2021.

Orders for the S13 open in October. The updated LT series can be specified with the 13-liter S13 engine mated to the T14 14-speed automated manual transmission with a more efficient two-stage aftertreatment system. Navistar will continue to offer a 15-liter Cummins X15 with Endurant transmission.

New Navistar LT dashboard buttons include parking maneuvers (turtles) and power modes. (Photo: Alan Adler/FreightWaves)

Compared to Navistar’s first-generation A26 engine specified with the Eaton-Cummins Endurant HD 12-speed overdrive automated transmission, the new S13 integrated powertrain, combined with the aero package, delivers up to 15% better fuel efficiency . It is 4% more efficient than the current A26 introduced in 2021.

The S13 weighs 30 to 52 pounds less than the A26 with the Endurant drivetrain. The S13 is the lightest 13-liter powertrain on the market, Grahe said. That could save a fleet $31,000 in fuel over five years based on diesel at $4 a gallon.

What’s new in the International LT?

The redesigned LT offers an improved aerodynamic package that includes:

  • Diesel Exhaust Fluid (DEF) and fuel filler closures to allow air to flow smoothly over the chassis skirts.
  • Steering wheel closures and modified lower valance trim to improve underbody airflow by restricting it through the wheel opening.
  • A new roof extension that improves air circulation between the tractor and the trailer space.

The updated front design adopts a family look for the bumper and grille. It is consistent with recent updates to other International truck models.

Inside the sleeper cab, a 9-inch sleeper mattress and a flip-down sleeper help maximize cabin space for truckers on the road when not driving.

The 9-inch flip-up mattress frees up space in the LT sleeper cabin (Photo: Navistar)

Electronic parking brake technology automatically engages the vehicle and trailer parking brakes if the driver forgets to apply them. A steering wheel airbag is optional.

Modular approach

The modular system design of the S13 allows for varied offerings across Traton’s brands. This speeds time to market and reduces production costs. Cross-brand development gave the North American market the first example of regional adaptation and validation. The engine is mounted practically in the same way in the conventional LT body as in the Scania cabover.

Work on the engine continued 24 hours a day, 7 days a week, around the world, at Traton’s operations in Europe, Brazil and North America.

It wasn’t always easy to deal with cultural differences before Navistar became part of the Traton family, Grahe said. He worked on the engine program from the start when he was an executive at Traton. Navistar’s lower level of investment – ​​Scania spent $400 million – was a factor. Hernandez dealt with adding shifts in Huntsville.

Neither Traton nor Navistar announced any specific total investment in the S13 project.

Navistar offers owners an S13 package that includes dealer-integrated software, integrated service products, and maintenance and repair contracts.

Editor’s note: Corrects spelling of Mark Hernandez and that Grahe was a Traton executive, not Scania. Adds that neither Traton nor Navistar disclosed a total investment in the engine program.

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Click for more FreightWaves articles by Alan Adler.

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