Company Claims It Has Invented the 'Ultimate Engine'

Craig Cole
by Craig Cole

As automakers scramble to develop more efficient engines to meet increasingly tight fuel economy regulations, one company is claiming its new technology will change the auto industry.

“[Our] engine will be 50 percent more efficient,” explained David Johnson, the energetic president and CEO of Achates Power, a company founded in 2004 with the goal of revolutionizing internal combustion.

As numbers go, that’s a borderline preposterous figure, but making it even more unbelievable is that its engine is not being compared to some bunker-fuel-burning container transport ship, rather a state-of-the-art, turbocharged, downsized rival with gasoline direct injection like a Ford EcoBoost powerplant, for instance. The company also projects that a diesel-powered version will be 30 percent more efficient than the best oil-burners on the market today.

At a time when automakers are fighting tooth and nail for half-percent efficiency gains, a claim like Johnson’s seems as far off as the colonization of Jupiter’s moons, but he remains enthusiastic. “We have a very big contribution to make.”

Achates Power: Different by Design

What sort of black magic has Achates Power discovered that can allegedly cut fuel consumption by such an astonishing amount? What it has developed is an opposed-piston, two-cycle, compression-ignition engine. “It’s cleaner, more efficient [and lower cost]… than anything else on the market,” said Johnson, plus it has dramatically fewer components.

In simple terms, this engine has two pistons per cylinder that move toward and away from each other during a combustion cycle. Naturally, there are two connecting rods and crankshafts to support this arrangement, but despite these extra pieces, the elimination of cylinder heads and associated valvetrain still dramatically cuts the overall component count. Quantifying this, the company claims a 2.7-liter three-cylinder opposed-piston engine has 60 percent fewer parts than a similarly sized supercharged V6, a reduction that could also lower costs by 10 percent.

SEE ALSO: Honda is Working on an Engine with Different-Sized Cylinders

Curiously, this overall design is hardly new; the first instances of opposed-piston engines date back to the late 19th century, with numerous examples being produced over the past 100 years. In fact, these engines have successfully powered things like ships, tanks, and aircraft.

But to date, this technology has never really been used in road-going vehicles, certainly not in any significant volume, which is something Achates Power is looking to change. In essence, it has taken a fundamentally tried-and-true idea and attacked it with copious amounts of modern engineering.

Aside from being simpler, cleaner and cheaper, this opposed-piston design is even energy agnostic. With appropriate calibration, it can run on gasoline, ethanol, natural gas, diesel, or even other fuels. For all these reasons and more, Johnson said, “This actually is the ultimate engine.”

ALSO SEE: Infiniti Introduces World’s First Production-Ready Variable Compression Ratio Engine

“Twincharged” Combustion

Unlike conventional four-cycle internal-combustion powerplants, Achates Power’s unique design requires forced induction; it could never operate naturally aspirated. According to Johnson, this is because “the pistons don’t do any work breathing in our engine.” In other words, they never create vacuum during an intake stroke or force exhaust gasses out the tailpipe like conventional engines.

For each combustion cycle, fresh air is forced into the cylinders by the blowers. This incoming stream also helps push the exhaust out. As the pistons move together the air gets compressed, then a precise amount of fuel is squirted into each chamber where it auto ignites, burning quickly and cleanly.

Superior thermal efficiency helps this opposed-piston design deliver up to 50 percent better efficiency. Heat loss to the cooling system is lower, the expansion ratio is higher, there are reduced pumping losses and it can even run a leaner air-fuel mixture.

Further improving efficiency, with less work to do a vehicle’s cooling system can be made lighter. Cleaner combustion also allows exhaust after-treatment systems to be downsized, reducing mass, complexity and cost.

Another benefit is this engine’s much flatter fuel map, which means it doesn’t need a transmission with some crazy number of speeds to deliver optimum fuel economy. Simply put, it operates more efficiently more of the time than a traditional four-cycle engine.

Road Ready… Almost

Proving its lofty claims, the company is putting together a drivable test vehicle. By the end of 2018, it will have completed work on a light-duty truck as well as a 2.7-liter three-cylinder opposed-piston diesel engine. This unit is expected to offer around 270 horsepower with 480 lb-ft of torque.

As for fuel consumption, Johnson said it will beat fully phased-in CAFE 2025 requirements. The rig it is building is estimated to deliver 25 miles per gallon in urban driving and 32 on the highway. Combined, it should average 28 mpg, figures that are better than what’s offered by some midsize sedans. However, this engine’s CAFE score could be as high as 37. Johnson said this engine design is the most cost-effective way to meet upcoming fuel-economy regulations.

SEE ALSO: Everything You Ever Wanted to Know About the Shelby GT350’s Engine

Of course, this engine works perfectly well with other efficiency-boosting technologies. If an automaker wants to go with lightweight materials, offer hybridization or run on biofuel, there’s no problem whatsoever.

Howdy, Partner!

Naturally, what Achates Power is developing has not escaped the notice of automakers. Right now, the company is working with nine different OEMs plus a handful of engine manufacturers to bring this exciting technology to market. It has also partnered with organizations including the U.S. Army and Argonne National Laboratory.

Not surprisingly, Achates Power’s hard efforts over the last dozen or so years is protected by a passel of patents. So far, it has been awarded 135, but an additional 230 are in the works.

Thanks to its combination of mechanical simplicity, combustion efficiency and power density it looks like the opposed-piston engine has a bright future. Johnson said in the early days of this project he used to question whether any manufacturer would ever introduce one of these engines, but “that day has long since passed.” He said an Achates Power-designed engine will reach the market, it’s just a question of when.

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Craig Cole
Craig Cole

Born and raised in metro Detroit, Craig was steeped in mechanics from childhood. He feels as much at home with a wrench or welding gun in his hand as he does behind the wheel or in front of a camera. Putting his Bachelor's Degree in Journalism to good use, he's always pumping out videos, reviews, and features for When the workday is over, he can be found out driving his fully restored 1936 Ford V8 sedan. Craig has covered the automotive industry full time for more than 10 years and is a member of the Automotive Press Association (APA) and Midwest Automotive Media Association (MAMA).

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  • Daniel Girald Daniel Girald on May 21, 2017

    I still believe Achates Power should also consider to release horizontal versions of their engine concept, which would be perfect for small aircraft, some marine applications, and eventually also make it easy to retrofit into certain cars and CUVs fitted with boxer engines. OTOH now that Chinese automakers are venturing into Western markets more frequently, licensing technologies from companies like Achates Power seems like an easy way to overcome their disadvantage not just in addressing the emissions compliance issue but eventually also overcome intelectual property infringement claims due to their frequent usage of copies of old Mitsubishi, Toyota and Isuzu engines.

  • Jonny_Vancouver Jonny_Vancouver on May 27, 2017

    I'm all for new tech, but isn't this too little, too late? I'm assuming there are a few reasons they are making a diesel prototype. But a hybrid truck would get better fuel economy and make the same or better torque.

    • Jonny_Vancouver Jonny_Vancouver on May 27, 2017

      I mean existing hybrid tech following the natural evolution of that tech, also vs. spending millions modernizing old internal combustion tech when everything is moving towards pure electric. that money could be better spent elsewhere, and those efficiency gains don't seem all that impressive.