Ecomotors OPOC Engine Slated for Mass Production

EcoMotors OPOC 2 stroke engine

EcoMotors Opposed Piston Opposed Cylinder 2 stroke engine

Ecomotors announced yesterday a joint venture with a subsidiary of Chinese auto maker FAW Group, outlining plans to begin producing the opposed piston engines in 2015:

The joint venture will build a plant in China's northern Shanxi province with the capacity to make 100,000 engines a year. The factory is expected to begin operating in the second half of next year.

This is great news for an engine that seems to have all of the right stuff to succeed, a good design, great tech specs and lots of high profile backers, like Bill Gates and Vinod Khosla, but, while everyone else is taking this press release at face value, I refer back to our earlier coverage of this engine and see we've noted other breaking news that made it appear things were almost ready to start, especially when they announced the development agreement with Navistar. That announcement was just over three years ago.

The Wall Street Journal also notes in the same article another deal in China with plans to produce 150,000 engines per year beginning in 2014.

I like this engine, it makes sense from an engineering perspective, but it will be interesting to see if this new announcement will result in any more engines produced than the last several times it showed up in the news.

Link: Wall Street Journal
Link: Ecomotors


  1. Paulinator says

    This is new-old technology. There are other variants of the same theme that make a lot more sense. I see in this engine layout more compromise than gain. I also detect some wishful thinking with respect to those ridiculously high aspect-ratio outboard connecting rods. I’ll wait for the design to prove itself at Le Mans before I’m a belieber.

  2. FREEMAN says

    Serious question: have any of these engines been made? I thought I saw something in a military application but can’t seem to find it. Maybe it was a similar engine.

  3. Tom Lyons says

    I can see that the two opposing pistons move away from each other after firing, which would be approximately double the rate of a single piston design. Since the pressure available for work drops precipitously as the cylinder volume increases, I have concerns about the efficiency of power production.
    Yes, there are two pistons which have double the area of one, so maybe that’s how they get around it. But it seems that would make for a short duration power pulse, regardless.

    Anyone have any comments about that?

    • Viv says

      Look up Deltics and Fairbank Morse engines, opposed piston engines have a history in big stationary and marine applications as well as the Roots T3/Detroit Diesel 2 strokes

    • Lee Wilcox says

      Served on a diesel sub that was powered by Fairbanks Morse. They were very durable engines that went a long time. As two stroke diesels they were a batch more simple than this drawing. When they broke it could be devastating.

      I have some trouble believing that there won’t be a lot of teething problems with all the rods etc. The FM diesel had two cranks connected by gears and two pistons/cyl. This appears to have a whole lot going on and that’s a whole lot that can break. Those rods look a little bit spindly.

      • Sebastian Wiers says

        The long rods are mostly loaded under tension, not compression. As such, ‘looks spindly’ is probably about correct; items loaded primarily in tension tend to be slender.

        • Paulinator says

          A loss of combustion (or any host of lesser mechanical failures) could result in high compressive or bending loads imparted on those slender rods. If they buckle the piston domes will slug it out briefly. Very briefly. Then all will be quiet.

          • Sebastian Wiers says

            I’ll willing to give them enough credit to know the force required to accelerate the outer pistons through the cycle at redline without aid of combustion, and design the rods to take that. Its pretty basic math, but not something I can judge by eyeball mk1.

    • Jiro says

      These are diesel engines with multiple injections of fuel. The first injection ignites, and then more fuel is injected and ignited until some point. I believe it is called constant pressure… but I am just guessing. As I am sure you saw, there is a long history of high efficiency engines using 2 pistons in one cylinder. Large generators and other large prime movers would be my expectation where power to weight is relevant. Not for ships where weight is not so important and space is more critical.

  4. Gildas says

    There’s talk in the marine sector to make “modern” Duxworth’s opposed diesel two strokes (but with twin crankshafts).

    Opposed twins have a number of manufacturing and maintenance defects…
    But they have a major plus, the NOX does not spike when the CO2 reduction reaches a certain point.

    However, the maintenance issues limit the unit power output to around 30 000Kw.

    Anyhow, if money is being spent on this tech, sooner or later we will see influence on motorbike engines.

  5. Onerpm says

    In 1939 an opposed cylinder engine was placed in a Crosley automobile. That engine was made by Waukesha, a company that is still in business.
    I had one that was applied to a WW2 military use as a wrecker winch power source. It was connected to a 6-1 gear box that really gave it some grunt.
    My only thought on this new engine is, it is a shame that a product developed with DAPRA funding, for our military is being manufactured in China.
    I hope they make them small enough for lawn mowers, tractors and generators. They sound as if they will be a nice power to weight engine.

    • Jeff Kavanaugh says

      Actually, I think there is a 13.5hp air-cooled version of this engine design that is used in military generators.

    • Renegade_Azzy says

      Probably because in the US when it comes to production, your money isnt worth what it used to be and thus, priced out of the market. If you want a new engine design to take off, you probably want to use it in a country where their economy is in need of vehicles, not one where we have a glut of vehicles and have to artificially cull them (cash for clunkers) to prop up unio… manufacturers.

      Trying to make things in the US is expensive. Cost of labor, materials, and lawyers drives it sky high. Not to mention that you are a bureaucratic regulation away from being shut down at any minute. Sad thing is, the open communists are a tad more predictable when it comes to red tape and corruption.

  6. Heretic Monk says

    My big problem with yet another claim about production at EcoMotors is they’ve said things like this before, and unlike the Segway, I wonder if they have any real intention of production. What I’ve seen of the grit on this one is they’re ONLY making them for boats and plan to build them for big diesel trucks. Their initial goal of building 50cc replacement motors for scooters (responsible for most of the air pollution in China and India), and 400cc engines for cars? No longer mentioned in their press releases. It seems the economics support truck and boat engines since there is bigger markup and profits in those. It is not unusual for a company with lofty goals to realize that fundraising becomes their primary source of income rather than the stated goal of air pollution reducing engines. But this whole thing SMELLS. They keep hiring people, then there’s silence. They announce new investors, but have no working models, no reports of fuel economy or maintenance, nothing on the engine being physically tested. NO reports on endurance. No demo models at engineering expos. NO participation in racing. No motorcycles or buses or cars using this engine. After this many years of “development” they don’t have any that will run? Just a colored animation video and claims of people throwing money at them. Isn’t that what Ponzi schemes do? “These famous people invested so we’re real honest engineers with a product you can’t touch or see in person or talk to anyone that has. Trust us.” Uh huh. Yeah, right. And there’s magical carburetors that will turn water into gasoline too. It stinks, and my gut tells me this isn’t legitimate.

  7. Lightfoot says

    I work for Navistar and saw one of these in a truck chassis at our warehouse in Elmhurst IL last summer (2013). At first we thought it was a chassis without an engine, but upon closer examination found that it had the opoc engine installed. I believe this unit is now packing on test miles somewhere in the US. Personally I’m very excited about this new technology, but a little disappointed that it’s being manufactured in China.

    • Paulinator says

      Well…I have to admit that I’m a skeptic. Can you please tell us a little more about the unit(s). Did it run? Did it pull a load? Did it spew out raw hydro-carbons or the fresh scent of lavender? Anything would help.

  8. says

    EcoMotors’ OPOC has significant investors (like Bill Gates); it has also significant issues to address.

    As a ported 2-stroke with conventional design (take the two “inner” pistons of OPOC basic module) it cannot help consuming lubricant (a lot of it). For special applications (electric generator sets, outboard engines, airplane engines) this may be acceptable, but for cars, motorcycles, trucks etc it is not allowed (emissions).

    The four pistons per basic unit of the OPOC are necessary for achieving a “vibration free” operation. At the same time EcoMotors claims simplicity and compactness.

    Take a look at the PatOP engine of pattakon at .
    It uses only two pistons per basic module (so one could claim that the OPOC of EcoMotors has 100% more parts than the PatOP) and it achieves a better “vibration free” quality than the OPOC. You can simply open the videos showing the PatOP prototype operating on Diesel fuel, standing free on a desk (single cylinder, 635cc, 17:1 compression ratio, 20 Kp total weight without the flywheel, 500mm total height).
    With its “crosshead” architecture, it has a “four stroke like” lubrication and lubricant consumption (just like the Achates Power opposed-piston wherein two crankshafts are necessary, instead of the one of the PatOP). This is so because the thrust loads are taken away from the cylinder ports.

    Then take a look at the OPRE engine at . When used in a range extender module (or REM) of an electric car, its basis is perfectly rid of inertia AND of combustion vibrations (better than the Wankel rotary engine, better than a conventional V-12).
    With a propeller secured on each crankshaft (as in the video at ) it results an advanced “neutral” propulsion unit for aircrafts, helicopters, paragliders etc. No reaction torque at all.
    The OPRE, like the PatOP and the Achates Power, is an opposed piston “crosshead” two stroke with “four stroke like” lubrication.

    Then read at about some significant problems of the “variable displacement” of EcoMotors OPOC; there are better, simpler, cheaper and more reliable ways to do the same.

    And if you want to see a through-scavenged two-stroke with TRUE four-stroke lubrication, with TRUE four-stroke specific lube consumption and with TRUE four-stroke scuffing resistance, take a look at the PatPortLess engine at and at the PatMar engine at .

    Manousos Pattakos

    • says

      So, doesn’t your engine design and Ecomotors’ bite each other, from an IP point of view? Have you succeeded in finding investors?

      • says

        Hello Ralph.

        No they don’t.

        EcoMotors’ OPOC is a pair of Junkers – Doxford engines ( see at the PatPOC engine in the pattakon web site) sharing the same crankshaft for the sake of a better balancing (the second order unbalanced forces of the Junkers – Doxford are completely balanced by the arrangement of the OPOC).
        For the rest, the lubrication etc issues of the Junkers – Doxford have not yet been really addressed by EcoMotors.
        This is why they don’t talk for using the OPOC engine in cars and trucks, but only in special applications (gen-sets, aviation etc) wherein the emissions and the specific lube consumption are not so strict.

        You can see (and study) the patents (i.e. the intellectual property / IP) granted to EcoMotors and those granted to pattakon.

        In EcoMotors they have the funds, they have the publicity (every time a guy in EcoMotors “coughs”, every magazine in the world publishes -or reproduces- an article for OPOC), they have the support (only the name of Bill Gates “opens” every door). What they don’t have is a good engine design.
        Unless I am wrong, after several years there is not yet an OPOC in a car or truck for tests by an independent third party.

        Get in the place of the independent inventors / researchers / makers and think how they feel seeing in the press, again and again and again, about the OPOC of EcoMotors, about how many parts less than the other engines it comprises (which is a false claim), about how many less fuel it will consume (which is also a false claim), about how “green” it will be (which is also a false claim), and so on.

        By the way, pattakon is preparing a Portable Flyer based on an 800cc Opposed Piston PatATi (PATtakon Asymmetric Transfer and Intake) prototype two stroke engine (15Kp / 33lb ready to fly). Take a look at the pattakon web site, at “Portable Flyer” and at “Asymmetric Timing”, and compare it to the Martin Jet Pack and to the Hover-bikes of Malloy and of Aeroflex.

        Manousos Pattakos

  9. says

    I have been reading a couple of times that OPOC lends itself best for stationary use. Wouldn’t OPOC then form the perfect motor to complement an electric motor? If so, what will be the smallest motor Ecomotors has in mind? Displacement? Power delivery?