Navistar debuts updated International A26 engine

Navistar announced significant updates to the International A26 engine, which now allows fleets to achieve 10% improved fuel economy since the engine’s initial launch, according to the OEM.

Previous design and system updates accounted for a 6% fuel efficiency improvement, Navistar reported, while the latest enhancements to the A26 (2021 GHG) provide additional 4% in fuel economy.

“These latest updates to the International A26 highlight Navistar’s ongoing commitment to improved vehicle efficiency and total cost of ownership for our customers,” Diane Hames, Navistar’s VP of marketing, said. “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. The addition of a variable water pump also 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, a variable geometry turbocharger delivers the desired boost air pressure across a 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 rpms 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 MAN D26 engine crankcase, this latest version produces up to 515hp 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,” Chet Ciesielski, VP of Navistar’s on-highway truck business, said. “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 trucks, the RH Series of regional haul vehicles, the HX Series for heavy-haul and various construction applications, and the HV Series for vocational applications.

The newest A26 will be on display during American Trucking Associations’ Management Conference and Exhibition Oct. 24-26 in Nashville, Tennessee, at booth No. 4131.