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

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

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 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.