International® A26 Engine Updates Further Improve Efficiency and Performance

Feb 14, 2022A26 Diesel Truck Engine, Development, IC Bus, Industry News, News, Technology

Latest engine enhancements add to a total 10% improved fuel economy since launch of A26

/PRNewswire/ — Navistar announced significant updates to the International® A26 engine, now allowing fleets to achieve 10% improved fuel economy since the engine’s initial launch.

“These latest updates to the International A26 highlight Navistar’s ongoing commitment to improved vehicle efficiency and total cost of ownership for our customers,” said Diane Hames, vice president, Marketing. “Our key drive continues to be meeting the demands of our customers today while helping them plan for the road ahead. Every incremental change helps to forge a path toward that more efficient future.”

The previous updates contributing to the 6% fuel efficiency improvement include more optimized engine and transmission calibrations mated with the Eaton Endurant automated manual transmission, a direct drive 2.15 ratio, and aerodynamic improvements to wheel coverings on drive axle wheels and the chassis.

The latest engine enhancements to the A26 (2021 GHG) that provide an additional 4% fuel economy benefit are achieved through engine design and system updates, including:

  • Combustion enhancements: An increased compression ratio from 18.5:1 to 20.5:1, delivers higher combustion efficiency, along with maximized fuel injection pressure from the 2500 bar high pressure common rail fuel system.
  • Optimized engine temperature control: The efficient design of the cylinder head coolant passages helps to reduce parasitic loss at the water pump, as well as the addition of a variable water pump provides more optimized run time versus constant “on.”
  • Air management system updates: An optimized exhaust gas recirculation (EGR) cooler and intake throttle valve create more efficient charge air flow. Additionally, the Variable Geometry Turbocharger delivers the desired boost air pressure across a wide range of engine speeds, loads and elevation.
  • Reduced engine speed without compromising power: A higher horsepower output provides maximum power when needed, while operating at lower rotations per minute (rpm) optimizes the amount of fuel consumed during operation.

The latest generation International A26 13-liter engine was designed to provide greater fuel efficiency without sacrificing power. Built from the proven MAN D26 engine crankcase, this latest version of the International A26 produces up to 515 horsepower and 1,850 lb.-ft. of torque.

“The updated International A26 provides the horsepower you’d expect from a 15L engine, while working harder at lower engine speeds,” said Chet Ciesielski, vice president, On-Highway Truck Business. “The active torque management at the pedal delivers the required amount of torque at the moment it’s needed while providing a smoother shifting experience for the driver.”

The A26 engine is available for order in the International® LT® Series of long-haul vehicles, RH™ Series of regional haul vehicles, the HX® Series for heavy-haul and various construction applications and the HV™ Series for select vocational applications.

The latest generation International A26 will be on display during the American Trucking Associations’ Management Conference and Exhibition (MCE) October 24-26 in Nashville, Tenn. at booth #4131. To learn more, visit

About Navistar
Navistar, Inc. (“Navistar”) is a purpose-driven company, reimagining how to deliver what matters to create more cohesive relationships, build higher-performing teams and find solutions where others don’t. Based in Lisle, Illinois, Navistar or its subsidiaries and affiliates produce International® brand commercial trucks and engines, IC Bus® brand school and commercial buses, all-makes OnCommand® Connection advanced connectivity services, and Fleetrite®, ReNEWeD® and Diamond Advantage® brand aftermarket parts and includes a Brazilian manufacturer of engines and gensets, MWM Motores Diesel e Geradores. With a history of innovation dating back to 1831, Navistar has more than 12,000 employees worldwide and is part of TRATON SE, a global champion of the truck and transport services industry. Additional information is available at

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SOURCE Navistar International Corporation

For further information: Navistar Media contact: Erica Schueller,, 331-332-3310; Navistar Investor contact: Ryan Campbell,, 331-332-7280; Website:

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