Achates Power Is Reinventing The Internal Combustion Engine

The internal combustion engine has been with us now for almost 120 years. During that time, it has gone from a snorting, unreliable monster to a docile servant whose tailpipe emissions can  be cleaner than the surrounding air. Generations of tinkers have proposed new ways to burn gasoline more efficiently, but few have ever made it from the test bench to production. The last “breakthrough” design was the Wankel rotary engine that burst on the scene 50 years ago. The Wankel is known for making a lot of power from a small, lightweight engine, but it is not as fuel efficient as a modern piston engine.

During World War II, a new internal combustion design was proposed that would theoretically be lighter and more powerful than a comparable piston engine. Instead of one piston connected to one connecting rod  connected to a crankshaft, this innovative design would have long cylinders with a piston at each end and two crankshafts. Instead of one BOOM! for each power stroke, it would go BOOM! BOOM! More booms mean more power. It was intended for use in aircraft because it made more power with less weight, but the advent of the jet engine pushed it aside as the world went racing ahead into a jet propelled future.

Not everyone forgot about the weird engine with the opposed piston design, however. For the past several years, Achates Power has been working on perfecting the concept. It has raised more than $100,000,000 in private investment and was recently awarded a further $9,000,000 by the U.S. Department of Energy’s Advanced Research Projects Agency – Energy. Achates Power will use the funds to work with the Argonne National Laboratory on a 3 liter, 3 cylinder version of the engine that could potentially power the pickup trucks and SUVs of the future.

Why all the hoopla about the opposed piston engine? Fuel economy. It’s pretty obvious the Super Duties and Escalades of the tomorrow are not going to meet the CAFE targets required by the EPA. The opposed piston engine promises a 20% improvement in gas mileage. That’s a really big deal. But wait! Isn’t the opposed piston engine a diesel and aren’t diesels frowned on these days, especially after the shenanigans Volkswagen has been guilty of?

Yup, they sure are. The big news is that Achates Power thinks it can convert its engine to run on gasoline and still make it work as a two stroke, compression ignition engine. That would eliminate the NOx and particulate problems associated with diesels and still achieve the dramatic fuel economy gains the opposed piston engine promises.

Achates Power will need lots of partners to pull this off and it has some pretty good ones already lined up. According to Forbes, General  Motors was deeply involved with what it called Homogenous Charge Compression Ignition (HCCI) compression ignition gasoline engines 15 years ago. This video shows how that process worked.

Delphi Systems is an automotive engineering company that was spun off by GM just before it imploded in bankruptcy in 2008. Delphi has a great deal of experience in the fuel injection systems needed to make compression ignition gasoline engines work. Argonne Labs has been working on similar technology for a decade. It also has significant computational engineering prowess. Putting Achates together with Delphi and Argonne Labs may be just the combination of resources needed to make the opposed piston engine commercially viable.

“Vehicle manufacturers are struggling to find cost effective ways to improve fuel efficiency by just a few percent points, but this combination (of Achates’ engine design and gasoline compression ignition technology) has the potential to dramatically exceed that number and be a major advance for the industry,” said Dan Hancock, president, DMH Strategic Consulting and retired vice president of General Motors Powertrain Global Engineering. “Combining two very clean, very efficient, and cost effective technologies may well yield a new paradigm in engine design that could help satisfy the challenges of ground mobility for decades.”

In other words, the internal combustion engine may not be dead quite yet.

Photo credit: Achates Power