Achates near-zero heavy-duty opposed-piston diesel enters fleet service; compliant with 2027 NOx levels

Achates Power announced that the 10.6-liter, heavy-duty opposed-piston, three-cylinder diesel engine it developed in a project funded by the California Air Resources Board (CARB) and several partners (earlier post) has entered fleet service with WALMART Corporation in a Peterbilt 579 tractor. It is the only diesel engine operating on the road capable of meeting CARB’s 2027 regulation, which requires a 90% reduction in emissions of NOx compared to current standards.

Achates10.6

The 10.6-liter engine. The three cylinders are in-line, with the opposed pistons moving vertically.


The project team also demonstrated that the engine reduces carbon dioxide by 10%. The Achates Power ultra-low-NOx engine is engineered to achieve superior fuel efficiency because of its lower heat losses, improved combustion and reduced pumping losses.

Click here to continue reading

This article originally appeared in Green Car Congress, April 7, 2022

News