Achates Power Brings an Efficiency Revolution To Detroit

Thus far, the North American International Auto Show has been a truck festival – more specifically, a green-truck fest. Ram showed a hybrid 1500. Ford revealed their V6 diesel. Chevrolet surprised with an inline-six diesel. Clearly the Big Three are looking at the calendar, with a big red circle over the 2025 CAFE standards looming like a dark cloud.

Achates Power, a fourteen-year-old startup from San Diego, has a different idea. By combining a variety of existing technologies – some of which date from before World War Two – they have developed an engine that they expect to meet 2025 fuel economy standards, emissions standards, and most importantly, the performance standards of light-truck buyers.

How does 37 mpg sound in a half-ton truck? That’s on gasoline. The Achates engine can also manage 42 mpg in the same truck running on diesel.

Indeed, the diesel engine is the focus of Achates, while compression-ignition with gasoline is a later development focus. The innovation on this is with the layout of the engine itself. Rather than the typical inline or vee, this engine is:

• Three-cylinder
• Six-opposed-piston
• Direct-injected
• Two-stroke
• Turbocharged and supercharged

In other words, a mouthful. As the cylinders are firing toward each other, there are a pair of crankshafts, but no cylinder heads. The lack of a complex valvetrain and cylinder heads will minimize heat and friction losses.

At 2.7 liters, the OP GCI (Opposed Piston Gasoline Compression Ignition) produces 270 horsepower and 480 lb-ft of torque, with a 16.5:1 compression ratio. The diesel version should deliver similar power figures, at 18.5:1 compression.

The Achates Power engine was developed with a $9 million grant from the US Department of Energy.

For the aircraft buffs in the house, this powertrain configuration might seem familiar. Junkers developed an opposed-piston diesel in the 1920s to power various aircraft. It was relatively successful despite the higher relative weight to avgas-powered radial engines.

I’m wondering how the engine will sound. I’m secretly hoping the exhaust note will resemble the two-stroke supercharged Detroit Diesel powerplants known as the “Screaming Jimmy.”

Achates Power announced a partnership with Aramco Services Company here at the 2018 Detroit Auto Show, as the Saudi-based oil company has an interest in making internal-combustion engines sustainable for the foreseeable future. Thus, Achates and Aramco have fitted a diesel 2.7-liter powerplant into a Ford F-150. They assure me that this isn’t a Ford-specific project – indeed, Mark Subramaniam, VP of Business Development for Achates Power, tells me that they have worked with many OEMs on various projects, and are actively shopping this engine technology to many potential partners. They expect to have the engine running and driving in the F-150 later this year.

[Images: © 2018 Chris Tonn; GIFs and truck image courtesy Achates Power]