Start-Ups Work to Reinvent the Combustion Engine

Jim Wilson/The New York Times

TESTING Engineers at Pinnacle Engines checking a prototype of its opposed piston engine, which it says can increase fuel efficiency.


Pinnacle’s Opposed Piston Engine

In this design, two pistons face each other, the space between them forming a combustion chamber. Eliminating the traditional cylinder head results in a lighter, cheaper and more efficient engine.

IN this city where Toyota Priuses clog the roads and battery-powered Tesla Roadsters and Chevrolet Volts can be spotted at the organic farmers market, the engine factory in a gritty industrial neighborhood near San Francisco Bay is a throwback to the automotive past.

Or a harbinger of the future. In the middle of a metal building, stacked with hulking racecar engines from the internal combustion engine’s golden age, sits a small contraption hooked to a forest of red, white and green wires and tubes that hang from the ceiling and snake around the floor.

In a control room at Hasselgren Engineering, a technician flips a switch and the device roars to life as a large computer screen displays the performance of this new type of engine, which its developer, Pinnacle Engines, says will be up to 50 percent more efficient than today’s power plants.

As the first mass-produced electric cars hit the streets, Pinnacle is just one of several start-ups backed by prominent Silicon Valley venture capitalists aiming to reinvent the century-old internal combustion engine. The big promise: vast improvements in fuel economy and reduced greenhouse gas emissions at a lower cost.

“While the buzz is all about electrics, the people who will actually adopt electrics are not a majority of the market,” said Monty Cleeves, who has kept Pinnacle under wraps since he founded the company in 2007. “The impact we will have over the next 15 to 20 years will be much larger than the impact of the electrics.”

Not long ago, the idea that entrepreneurs could attract tens of millions of dollars in venture capital to develop a new kind of engine would have seemed ludicrous. The big automakers have kept engine development to themselves, steadily improving the performance of a profitable technology that has served them well for more than a 100 years.

“Our engines are built into the DNA of our vehicles,” said Brett Hinds, engine design manager for Ford in Dearborn, Mich. “We at Ford are still committed to thinking of engines as part of our fundamentals.”

But the upheaval in the global car industry, new fuel efficiency standards for commercial vehicles, climate change concerns and the rise of China and India as automotive markets have opened the door to start-ups like Pinnacle

“Many automotive houses don’t buy engines from outside, but in the truck market people do,” said Rohini Chakravarthy, a partner at NEA, a venture capital firm in Menlo Park, Calif., that has invested in Pinnacle. “In Asia, there’s tremendous demand, and you’re not going up against the same level of incumbents.”

Pinnacle executives, for instance, said they had signed a deal to license their engine technology to a major Asian scooter manufacturer, which they declined to identify, for production in early 2013.

EcoMotors, a Detroit area start-up backed by Khosla Ventures and Bill Gates, has signed a development agreement with Navistar, the heavy truck and engine manufacturer, and a Chinese company it would not name. Achates Power, a San Diego engine start-up, is in talks with automakers, according to its chief executive, David Johnson, who said he also had met with potential customers in China and India.

All three companies are developing variations on an opposed piston engine, a technology used in airplanes and ships in the mid-20th century, but long considered too expensive and unworkable for automobiles.

Opposed piston engines eliminate the cylinder head, which serves as the combustion chamber for a conventional engine. Instead, two pistons face each other and the space between them forms the combustion chamber where fuel is ignited. Discarding the heavy cylinder head allows opposed piston engines to be lighter and cheaper to make. Typically, two-thirds of the energy generated by a conventional engine is wasted as heat; an opposed piston design is able to tap more energy to propel a vehicle.

The challenge has been to create a reliable opposed piston engine suitable for vehicles, something Mr. Cleeves said he had been pondering since he was a mechanical engineering student 40 years ago.

In the late 1970s, he began working in the burgeoning computer chip industry that was transforming the apricot and plum orchards of the Santa Clara Valley into Silicon Valley.

“I stayed 30 years in semiconductors as my day job, but worked on cars in the garage as my passion in the evenings,” said Mr. Cleeves, a bespectacled and gray-bearded 59-year-old who speaks with a professorial air.

On long nighttime drives to Southern California to visit relatives, Mr. Cleeves would design engines in his head while his wife and two children slept.

“Over the course of many years and many thousands of miles, I had the chance to put the engine together, at least mentally,” Mr. Cleeves said at Pinnacle’s unmarked offices and garage in San Carlos, Calif.

The prototype being tested in Berkeley is a version of a one-cylinder, four-stroke opposed piston gasoline engine designed to power scooters and three-wheel auto rickshaws in Asia. Pinnacle executives said that 500 hours of testing verified by an independent company showed that the engine was 30 percent more efficient than current scooter engines while emitting fewer pollutants.

Executives said software simulations indicated that an automotive version of its Cleeves Cycle engine would increase the fuel economy of a Fiat 500 to 59 miles a gallon from 33 with no performance loss.

EcoMotors is also claiming up to a 50 percent improvement in efficiency for its two-stroke diesel opposed piston engine being developed for heavy-duty trucks. Conventional two-stroke engines emit more greenhouse gases and are commonly found in scooters, lawnmowers and outboard boat engines.

“We’re on our sixth engine, so it’s not a science fair project at this point,” said Donald Runkle, EcoMotors’ chief executive, a General Motors veteran.

The key, he said, was high power output and an electrically controlled turbocharger that resulted in a small lightweight engine with emissions comparable to a four-stroke power plant.

“You can stack these engine modules together,” said Mr. Runkle, noting that a module can be shut down when full power is not needed, saving fuel.

Mr. Johnson, the chief executive of Achates Power, said his company’s two-stroke opposed piston diesel engine would most likely be used in commercial vehicles, but it also could be installed in plug-in electric hybrid cars like the Chevrolet Volt.

“The Volt needs a better engine,” said Mr. Johnson, adding that 1,600 hours of testing had shown Achates’s engine was 15 percent more efficient than conventional diesel counterparts.

The major automakers aren’t exactly sitting still. Ford claims a 20 percent improvement in fuel economy and a 15 percent reduction in emissions from its gas-turbo, direct-injection EcoBoost technology. Coming start-stop technology that shuts down a car’s engine at traffic lights will increase fuel economy up to 10 percent, Ford says.

“We think your conventional inline engine is still the appropriate architecture in the near term,” said Mr. Hinds, Ford’s engine design manager.

Pinnacle’s chief executive, Ron Hoge, said a bigger leap was needed. “It’s the challenge of incremental thinking versus radical thinking,” said Mr. Hoge, a former executive at the engine maker Cummins. “If we’re only going to make incremental improvements, we’re not going to solve our problems in the world, so someone has to step forward.”


1 Comment

  1. The PatOP opposed piston engine at is a single-crankshaft vibration-free direct injection Diesel.
    By nature it is a crosshead engine (like the giant Sulzer marine engines) yet a short one: the height of the first PatOP prototype is 500mm (635cc capacity, 79.5mm bore, 64+64=128mm stroke).
    The crosshead architecture is vital for engines like the EcoMotors’ OPOC because it frees the piston skirts from the thrust loads, allowing four-stroke-like lubrication and lubricant consumption.
    The crosshead is also important for engines like the Pinnacle, because it frees the reciprocating cylinder liner from additional loads, deformation, friction and weight.

    The full balanced PatOP engine is short and compact because it doesn’t need an opposed cylinder (case of the OPOC of EcoMotors) to get vibration-free, as shown in the videos wherein the PatOP is running on Diesel fuel, standing free on a desk.

    The variable capacity (stackable modules) technology of EcoMotors has some weaknesses, as explained at .

    For divided load applications, like a range extender with two counter-rotating electric generators, the two-crankshaft OPRE opposed piston engine at is simpler, lighter, cheaper and more compact than the two-crankshaft opposed piston Achates and Pinnacle engines.

    Both, the PatOP and the OPRE engines, are characterized by a substantially longer piston dwell near the combustion dead center: they provide some 35% additional time as compared to the Pinnacle, and some 20% additional time as compared to the EcoMotors’ OPOC, for the injection, penetration, vaporization and combustion of the Diesel fuel, improving the fuel efficiency at medium low revs and increasing the power concentration by providing the peak power at higher revs.

    It would be nice EcoMotors, Achates-power and Pinnacle to comment on the above.

    Manousos Pattakos

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