30 Oct 2013

Re-engineering the internal combustion engine to higher MPGs at a lower cost with fewer emissions

Written by Jim Pierobon

For all the advances with hybrid and pure electric vehicles and the attention they are grabbing, personal, commercial and government vehicles around the world will be using enormous volumes of gasoline and diesel fuel for decades to come. Investors and innovators know there is a lot of money to be made improving the efficiency of internal combustion engines. If that can be accomplished at a lower cost and with fewer emissions, all the better.

Well that day of reckoning  may not be far off.  

One of the handful of companies trying to re-engineer the internal combustion engine  – San Diego-based Achates Power – has been sharply focused on new engine architectures since 2004.  Its “opposed piston, two-stroke” design initially for government and commercial vehicles is drawing significant interest from investors. And it’s now working with a customer it’s permitted to identify:  the U.S. Army’s Tank Automotive Research, Development and Engineering Center.

Now I’m no auto geek. My two family cars have logged more than a combined 400,000 miles.  My wife and I are waiting as long as we can to make one of our next purchases the most efficient internal combustion sedan on the market. So I’m tracking the auto industry’s progress (or lack thereof) in achieving the fleet-average miles-per-gallon requirements set by California and the U.S. government. I’ve got high (and perhaps unrealistic) hopes that emissions from any improved design will be less, power won’t be sacrificed, the price tag will be affordable and they’ll be quiet-enough to drive.

At least three other U.S. companies are in hot pursuit of such a game-changing engine design:   Pinnacle Engines in San Carlos, CA; EcoMotors in Detroit; and Transonic Combustion in Transonic Combustion in Camarillo, California. Toyota and General Motors have been tinkering with “homogeneous charge compress ignition” (HCCI) technology with no public results I could find. Here is why Achates Power caught my eye.

 Securing America’s Future Energy shined a bright spotlight on Achates Power October 16 as the runner-up in its Emerging Innovation Award for a technology that is “driving fundamental improvements in energy security, and that (has) the potential to reach the market within the next five years.”

This award comes when a lot of people interested in more secure energy sources are taking stock of what’s been achieved since the Arab Oil Embargo 40 years ago. Earlier this year, the research firm Frost & Sullivan selected Achates Power for its New Product Innovation Award for North American Medium and Heavy-duty Commercial Vehicle Engines.

Just last week, Achates Power secured a Series C round of funds from its venture capital partners led by Sequoia Capital Partners and RockPort Capital Partners. To date, according to CEO David Johnson, Achates Power has raised $90 million and secured 23 U.S. patents and 14 foreign patents relevant to its engine design.

Heavy and medium-duty trucks are understandably the initial target markets for Achates Power. But Johnson is quick to point out that their design can work just as well in passenger vehicles. In addition, the engine can be configured to use unleaded gasoline, natural gas and certain biofuels. He said more than 4,500 hours of rigorous laboratory tests are showing diesel fuel savings of at least 20 percent and gasoline savings exceeding 50 percent.  With those efficiencies, passenger vehicles with Achates-designed engines, in time, could approach a fleet average of 100 miles per gallon.

Global Engine Market v3

Frost & Sullivan researchers weighed a typical heavy-duty truck scenario where a convention diesel-engine powered travels an average 120,000 miles a year at an average fuel efficiency of 6.5 miles per gallon. That comes to about 18,460 gallons. With the fuel efficiency benefit of Achates’ engines advances in the lab that translate to 3,690 gallons of fuel saved, or about $14,000 savings in fuel costs annually.

What makes such a huge advance in an engine design that has served as a basis for internal combustion engines since the 1930s and currently powers small marine motors and even some household outdoor appliances like weed whackers?  Johnson said the company’s 50 engineers and scientists have assembled the necessary computer technology to work with high pressure fuel injectors and far more advanced turbochargers. It is far easier, he said, to determine what engine parts are needed and which ones aren’t.

The Achates Power design eliminates two of the traditional four engine strokes – intake, compression, power and exhaust – into just the intake and exhaust strokes.   There are just three cylinders, versus four or more cylinders in virtually all vehicles today. There is a piston at both ends of each cylinder.

Achates Power engine

This is Achates Power’s A48 engine. CREDIT: Achates Power, Inc.

In a conventional engine, a piston moves inside each cylinder, compressing fuel and air against a cylinder head. A significant amount of energy in the fuel is ‘used’ to heat the cylinder head rather than drive a piston thereby hindering efficiency. There are no cylinder heads in the Achates Power design. This design also negates the need for a valve train, camshafts, pushrods, rocker arms, valves and valve springs. Their absence lowers friction, reduces engine size and weight and minimizes cost.

Opposed-piston, two-stroke engines fire in every cylinder during every engine revolution. This, combined with having two pistons per cylinder, leads to a larger cylinder volume per fuel injected. The resulting air-fuel mixture is leaner, making the combustion more efficient and reducing emissions. With higher thermal efficiency, more energy from the fuel is transformed into mechanical power rather than lost as heat.

The opposed-piston engine architecture has enjoyed only marginal market potential until now due largely to the entrenched position of conventional, four-stroke internal combustion engines. That has been the only engine technology available in the industry from small cars to large trucks. Reliability, durability on long-haul, on-highway usage and unproven emission compliance are additional hurdles that must be overcome.

The invention of the opposed-piston engine is credited to German engineer Hugo Junkers as the 1800’s drew to a close. While variations of the subsequent “Junkers Jumo” design have improved power density and fuel efficiency, the “basic design contains a number of deficiencies,” according patent applications by Achates Power’s chief scientist, James Lemke, who founded the company with an investment from John Walton, son of Wal Mart founder Sam Walton.

James Lemke, Founder & Chief Scientist CREDIT Achates Power

Achates Power Founder & Chief Scientist, James Lemke CREDIT: Achates Power, Inc.

For history buffs, Wikipedia outlines how Junkers was forced to work with engineers designing German’s Fokker combat aircraft leading up to World War I. In that war’s aftermath, Junkers butted heads with the Third Reich.  Nazi authorities responded by securing ownership of his patents and the majority of shares of his remaining companies.

Emission and fuel efficiency regulations in North America are the most stringent in the world. They’re about to get even tougher with regulations on greenhouse gases phasing in starting in model year 2014, expanding in scope through model year 2018. With medium and heavy-duty trucks accounting for about 22 percent of all transportation-related greenhouse gas emissions, major truck and engine equipment manufacturers, as well as, truck owners invariably are looking for cleaner and leaner diesel engines that deliver the lowest upfront cost and reduced lifecycle costs.  With progressively higher adoption, passenger cars and light-duty trucks might not be far behind.

Which commercial truck manufacturer will be the first to commit to adopt the Achates Power design?  Or might a company such as Cummins Engine be the first? Johnson says non-disclosure agreements prohibit the company from identifying prospective customers. Neither GM, Ford, BMW North America nor Cummins responded to emails and/or phone inquiries.

Jim Motavalli, a prominent auto writer and clean energy advocate whose work is often carried online by The New York Times and the Mother Nature Network, withheld judgment about Achates Power for an assessment about a year ago.

In September of 2012, Motavalli wrote:  “Before I proclaim this engine the greatest thing since sliced bread, I’d like to see it much further down the road. I’d want to see independent fuel economy and emissions validation. I’d want to see noise, vibration and harshness studies . . . Frankly, I’ve had other meetings with ‘breakthrough’ engine companies whose tech never amounted to anything.”

 The next few years will tell if Achates’ new design is the real deal.

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