Sometimes, the terms boxer engine and flat engine are used interchangeably, even though the two are not the same. What's the difference? Which one is better?

Argonne, which is partnering with Achates Power to develop a hydrogen-powered engine, recently began testing the engine in Argonne’s state-of-the-art facilities. In a groundbreaking demonstration, ...

An OP can be configured and packaged to fit the vehicle it’s intended for. For trucks, the cylinders are likely to be vertical or slanted. Photo: Achates Power Security’s tight at Achates Power Inc.