The opposed-piston motor has been around for almost 100 years, but it's never been put into a land vehicle before, until now. Here's what you need to know.

I’m talking about the opposed-piston engine. Opposed-piston engines have been around since the late-19th century, so the idea isn’t new.

Unlike conventional diesels, the Commer Knocker engine used opposed pistons and a single crankshaft, giving it big torque, ...

Opposed pistons share a combustion chamber in this venerable engine design, and Achates's refined version claims fuel-economy improvements.

Opposed-piston engines are not a new concept. The original idea dates back to 1882 and James Atkinson, who developed the Atkinson differential engine.

This pushes the pistons out, and the cycle repeats itself. This all results in an engine that is small, power dense, and quite efficient.

The opposed-piston (OP) engine is an old invention that has mostly been used in heavy-duty machines like tanks and ships, but proponents believe it could revolutionize the internal combustion ...

Radical new engines make a run at reality in the F-150 Achates' highly efficient opposed piston engine is set to find a home in the Ford. Brian Cooley explains what makes it special.

An opposed-piston engine replaces the cylinder head with another set of pistons, each sharing a common cylinder, like a boxer engine but with no heads.

An opposed-piston engine is a two-stroke engine with separate oil flow. It has no cylinder heads and no valves, both sources of considerable loss of heat and power in conventional combustion engines.