Achates Claims Huge Gains in Fuel Efficiency of Opposed-Piston Design

Achates Power was founded in 2004 with the idea of re-engineering the opposed-piston, two-stroke engine, a design that has been used in ships and submarines, aircraft, trucks, and other vehicles for more than 100 years.

Such engines fell out of favor with the adoption of stricter tailpipe emission standards during the 1970s. But Achates founder James Lemke, an adjunct engineering professor at UC San Diego, saw advantages in the design. Lemke figured that using advanced cylinder bore manufacturing techniques and materials, new fuel injection technology, synthetic oils, and other engineering advances would significantly increase fuel efficiency, reduce greenhouse gases, and cut the overall cost of a diesel-powered engine.

Achates has a video that helps explain how the opposed-piston design operates more efficiently. Because there is no cylinder head, high-pressure gasket, or valve train, the engine weighs about one-third less than a conventional diesel engine. Because it requires less machining and assembly, the design also is less expensive and easier to manufacture.

Lemke, a serial entrepreneur and expert in magnetic recording equipment and materials, wasn’t the only innovator to see the advantages. There’s been something of a renaissance in opposed-piston engine design over the past decade, and a flourishing of venture-backed startups that includes Achates, San Carlos, CA-based Pinnacle Engines, and EcoMotors in Detroit.

Achates Power, Opposed-Piston Engine, A48 Engine

Achates Power A48 Engine

In San Diego, Achates now has 40 employees and has raised about $70 million in venture funding from Sequoia Capital Partners, RockPort Capital Partners, Madrone Capital Partners, InterWest Partners, and Triangle Peak Partners. When I visited Achates’ lab, CEO David Johnson predicted the company’s design would revolutionize the automotive industry.

Like many startups in the auto industry, Achates also faces an inherent challenge. Its business model relies on working closely with engine makers that want to adopt Achates’ innovative design. “We see ourselves as disruptive, but not disruptive of everything,” Johnson said. “We’re disruptive as to the architecture of the internal combustion engine.”

Working under an engineering services contract with major automakers can be a good business, and Achates is looking to … Next Page »

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Bruce V. Bigelow was the editor of Xconomy San Diego from 2008 to 2018. Read more about his life and work here. Follow @bvbigelow

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2 responses to “Achates Claims Huge Gains in Fuel Efficiency of Opposed-Piston Design”

  1. show_us_something says:

    Seems like an exaggeration.

    There are LOTS of technologies that increases mileage by 15%. Hybrids do it easily. Direct fuel injection makes a huge difference. Turbos, etc.

    The question is the cost and reliability.

  2. Mick says:

    Seems like having less parts and a more Boxer-like cycle for better heat dissipation would make it ultimately more reliable and at least somewhat cheaper.