Navistar updates International A26 diesel

By Mike Brezonick20 October 2021

International A26 engine GHG 2021 Navistar said it has made a range of enhancements to its latest generation A26 diesel engine.

Navistar announced significant updates to its International A26 engine, which the company said allows fleets to achieve 10% improved fuel economy since the engine’s initial launch in 2016.

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 new generation International A26 is a 13 L built from the MAN D26 engine platform. It is available I ratings up to 515 hp with 1850 lb. ft. of torque.

“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 2.15:1 ratio, and aerodynamic improvements to wheel coverings on drive axle wheels and the chassis.

Navistar said 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 36,000 psi (2500 bar) fuel injection pressure from a high-pressure common rail fuel system.

Optimized engine temperature control: Navistar said 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, the company said. Additionally, a variable geometry turbocharger is designed to deliver 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, Navistar said.

“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.

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