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.

Brian Cooley Editor at Large
Brian Cooley is CNET's Editor at large and has been with the brand since 1995. He currently focuses on electrification of vehicles but also follows the big trends in smart home, digital healthcare, 5G, the future of food, and augmented & virtual realities. Cooley is a sought after presenter by brands and their agencies when they want to understand how consumers react to new technologies. He has been a regular featured speaker at CES, Cannes Lions, Advertising Week and the Publicis HealthFront. He was born and raised in Silicon Valley when Apple's campus was mostly apricots.
Expertise Automotive technology, smart home, digital health. Credentials
  • 5G Technician, ETA International
Brian Cooley
2 min read
Watch this: Radical new engine makes a run at reality

Achates Power and Aramco Services recently announced they will put a Ford F-150 on the road with a novel opposed piston engine under the hood, hoping to prove this exotic engine design is the future of burning gas powered vehicles.  

Achates' opposed piston engine is a two-cycle, 2.7-liter, three-cylinder with six pistons arranged in a pair per cylinder, working against each other rather than each piston in its own cylinder working against a head and valves. Achates controls the engine's response curve by modulating pressures through both a supercharger and a turbo instead of varying valve lift and timing. No spark plugs, either -- the Achates design uses compression ignition like a diesel, but runs on gasoline. 


The Achates opposed piston engine places two opposed pistons in each cylinder. Note the intake, exhaust and fuel injection ports cut into the cylinder walls, replacing a traditional head and valve train with a two-stroke design. Also, no spark plugs.

Achates Power

The big idea is to end up with a more thermally efficient engine that gets more out of each drop of fuel. That's not a very high bar: Today's gas engines use around 25 percent of each gallon of gas to move the car, the rest going to wasted heat. Achates says it can push that to around 45 percent which, in the case of an F-150, could mean 37 mpg on a CAFE basis and perhaps 33 mpg observed. That's a big jump in a vehicle that uses a lot of fuel per mile, travels a lot of miles and sells in the highest numbers each year.

Achates isn't the only company developing a modern opposed piston engine for cars and light trucks Pinnacle Engines has a version that uses a four-cycle process and spark ignition that it says will see its first test applications in the Chinese market.  EcoMotors was another prominent competitor, but its intellectual property was put up for sale in late 2017.

Aramco Services, the US arm of the Saudi oil apparatus, will start testing the F-150 with an Achates opposed piston engine by late 2018. The auto industry will be interested to see what that proves about the engine's efficiency, reliability, emissions compliance and total cost to integrate into existing vehicle platforms.

Don't sweat the truck stuff in the 2018 Ford F-150

See all photos