International A26 updates improve efficiency, performance

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Updated Oct 21, 2021
Improved International A26 engine

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

Previous design and system updates account for a 6 percent fuel efficiency improvement, while the latest engine enhancements to the A26 (2021 GHG) provide an additional 4 percent fuel economy benefit.

“These latest updates to the International A26 highlight Navistar’s ongoing commitment to improved vehicle efficiency and total cost of ownership for our customers,” says 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 percent 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 percent 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,” says 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.

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