• 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 engine.
• The OP engine is more efficient and produces fewer emissions than conventional engines due to its unique design and lack of valves and cylinder heads. It has the potential to significantly reduce fuel costs and meet emission regulations.
• Achates Power, the leading developer of OP engines, aims to license its technology to automakers and has already achieved success with engine debuts on a Ford F-150 and a Peterbilt tractor. However, the main challenge lies in changing people’s perceptions of two-stroke engines and gaining mainstream acceptance.

The opposed-piston (OP) engine is an invention as old as the automobile itself. However, since its emergence in the late 19th century, the OP engine has predominantly featured in tanks, trains, submarines, and ships – but not cars. The range was the main reason manufacturers fitted OP engines in heavy-duty machines – a 1930s plane could fly 6,000 miles on a single tank.