Thanks to the latest engine enhancements to the A26 (2021 GHG), the engine now boasts an additional 4% fuel economy benefit, achieved through engine design and system updates, compared with the A26 engine at launch, according to Navistar. Built from the MAN D26 engine crankcase, this latest version of the International A26 produces up to 515 horsepower and 1,850 lb.-ft. of torque.
Navistar outlined the biggest A26 engine enhancements.
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 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 HP output provides maximum power when needed, while operating at lower RPM optimizes the amount of fuel consumed during operation.
When paired with International LT Series updates, Navistar noted that it adds up to a 6% fuel efficiency improvement. These design and system updates include more optimized engine and transmission calibrations mated with the Eaton Cummins Endurant automated manual transmission, a direct drive 2.15 ratio and aerodynamic improvements to wheel coverings on drive axle wheels and the chassis.
