Reliability through refinement: International’s A26 engine lays the groundwork for the engine platform’s tomorrow

International’s A26 engine lays the groundwork for the engine platform’s tomorrow

International LT

Denny Mooney never stops moving.

Even as he sits in the passenger seat of an International LT Series truck, outfitted with International’s new A26 12.4-liter engine, the mind of Navistar Inc.’s group vice president of global engineering races with insight and his gesturing hands punctuate his every point.

“If you take the combination of the aero improvements from the ProStar to LT Series, and then the engine improvements from the previous generation ProStar N13 to the new A26, you can achieve up to 9% fuel economy,” Denny explains as the A26 growls, RPMs revving quickly up to cruising speed. A cool autumn breeze blows bright leaves across the three-mile oval at Navistar’s New Carlisle, Ind., but the truck’s Sunrise Orange Metallic paint job puts the foliage to shame as the October sun streaks across the hood.

Denny pauses just for a moment to let the engine’s quietness take center stage. “This is the quietest big bore, linehaul engine in the market,” he says, breaking the silence without straining his voice. “That was a big deal from a driver fatigue standpoint.”

Navistar’s strategic alliance with Volkswagen Truck and Bus played a large role in brining the A26 engine to market. The engine is built from the MAN D26 engine Compacted Graphite Iron (CGI) crankcase, producing 475 HP and 1,750 lb./ft. of torque. But the engine isn’t a simple rebranding—both the Navistar and Volkswagen teams worked hand in hand to craft an engine that meets North American application demands.

Denny Mooney

“The base engine itself is part of what makes it so quiet,” Denny says. “Structurally, It’s a very, very sound engine. But I would tell you the calibration, the controls, the variable geometry turbo [VGT]—those are unique to us. The MAN D26 had a twin turbo, but we’ve gone with a VGT. The old twin turbo had an interstage cooler, and the cooling system was a lot more complicated. That system had a low temperature radiator and a high temperature radiator. The VGT allowed us to get rid of one of the radiators making it much, much easier to service. From a quality standpoint, that means fewer joints and fewer hoses.

“My philosophy is if the part isn’t there, you’re not going to have a problem with it.”

That’s a philosophy that shines through in the A26’s design: a titanium compressor wheel sports a simplified single-stage design; a new cylinder head coolant passages that are 50% less restrictive to reduce parasitic loss to the water pump; it’s built with a high-pressure common rail fuel system; and smaller piston cooling jets increase oil pressure to improve lubrication, increasing oil change service intervals up to 70,000 miles.

The A26 is standard in International’s LT and RH Series and will also be making its way into the HX Series and recently announced HV Series.

Watch FE test drive the International HV with an A26 engine here.

“The Workstar was very successful, and the HV Series moves the needle forward in terms of driver acceptance,” Denny says. “It turns out the A26 is also a perfect vocational engine because it’s very lightweight. A lot of the vocational trucks, depending on what they’re used for, gross out on weight. Those fleets want that front axle weight to be as light as they can get it.”

At 2,299 lbs., the A26 is 55 lbs. lighter than the engine it replaces, and also enables 200 lbs. of additional weight reduction in vehicle-mounted components.

Moving forward


Two months later, winter’s chilling wind whips across the Windy City reaching 25 miles west to Lisle, Ill., where light snow flurries dance around International’s sprawling headquarters. Denny has eschewed a traditional office and has set up shop in a cubicle surrounded by International employees of all responsibility levels. He takes a break from working on financial reports to talk about the future of the industry: What the unveiling of electric trucks means and the role of integrated proprietary powertrains in today’s market.

Both topics touch on announcements International made at the North American Commercial Vehicle Show—that a Class 6/7 medium-duty all-electric truck is in the works with a launch within the 2019/2020 time frame, and that an International transmission to pair with its new engine is on the way and could be seen as early as 2021.
Darren Gosbee, Navistar’s vice president of advanced technologies, casually pops over the top of Denny’s low-rise cubical and asks if he’s ready for the meeting. Denny is on the move again.

As they walk to a near-by conference room, Denny explains that the cubicle set up is only temporary—International’s office is moving toward a Silicon Valley-inspired open-office concept. Wherever you want to sit that day is where you sit. Need to work across teams? Just pick up your gear and head over to the next table.

“We’re still working out the details,” he says, “but it’s about collaboration, working together and not being tied to an office.”

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Today, Denny has pulled together Gosbee and his chief engineer, Shane Spencer, for a near final, pre-prototype overview of International’s next engine iteration—the follow-up to the A26—and engine design plans for models well beyond 2021. Walking through the design changes is a delicate balance of technology investment and customer ROI. “Anything we implement on the engine, we plan for an 18-month return on investment for the customer,” Denny says.

While fleets may bristle at an increase in engine technology after being burned by earlier engine models across the industry trying to meet stringent Greenhouse Gas emission standards, Denny details how technology is actually improving engine reliability. “I know there are fleets out there with 2014, 2015 engines still living the dream,” he says with a wink. Sarcasm noted. “But as engine and aftertreatment technology evolves, it becomes more reliable.”

Think about the smartphone in your pocket. Twenty years ago, cellphones were big bulky blocks with shoddy cell service. Today, you have more computing power in your hand than NASA astronauts had during the Apollo missions. The functionality and reliability comparisons are so far apart it’s almost unfair to look backward. Heavy-duty engines are evolving in the same way.

After some good-natured banter over engine technologies that Denny’s team would like to implement but know that the ROI math for the customer doesn’t jive just yet—moving them to the back burner until they’re ready for prime time—the team disbands, heading off in different directions toward different teams to execute their plan. Denny walks across Navistar’s campus to visit with another design team. “These are the guys responsible for everything you can see and touch on the truck,” he says.

The cubicle walls here are even shorter, announcing that mobility is key in this department as well. The walls are plastered with truck design concepts—some we’ve already seen and a few “what if”s that have yet to be unveiled.

Denny doesn’t linger too long before making his way over to the Powerwall—a 47-ft. wide by 15-ft. tall screen that puts an IMAX to shame. He reviews slides featuring life-size images of International’s LT Series to prep for upcoming customer meetings, shakes his team members’ hands and then Denny is on the move again. Denny knows that the trucks of tomorrow starts with strategies created today, and today there’s work to be done.

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