• Aug 2, 2009
People have been predicting the death of the internal combustion engine for at least 50 years. Thing is, most of the folks making the predictions have themselves died, or been silenced by the fact that ICE is still here and it's better than ever. Still, the technology could be improved. All that sound and all that heat is just inefficient waste. And what about parasitic losses, like power steering pumps and valve train? Well, some OEMs (like Ford) are switching to mileage boosting electronic steering to save some MPG. However, electric valves are a long ways off. Not only would they be infinitely variable, but removing the chains, rods and springs needed to run conventional valves would increase mileage by 20%, at least. And that's just one route.

Another is the EcoMotors International (EM) opoc engine, aka open piston, opposed cylinder. Here's how it works. Instead of an I or a V pattern, EM's opoc is laid out like a two-cylinder boxer engine. However, each cylinder contains two pistons, and they are facing each other. This gives you four rods turning the crankshaft, with no cylinder heads and no valve train (for the record, we're not sure how fuel/air enters and exits). The opoc engine is also a two-stroke, guaranteeing lots of quick torque, but it "runs as a fully balanced 4-cylinder 4-stroke engine."

Shrinky-dinkying the engine has a whole host of other benefits that EM lumps together under the banner, "power density." They include: lower weight and smaller size, fewer materials, less friction, higher MPG, lower missions and less heat rejection. And as the engine is working against itself, there's plenty of built in noise cancellation. Power? Burning diesel, two 100 mm cylinders produce 325 hp and 664 lb-ft of torque @ 2,100 rpm. Nice. And thanks to Eugene for the tip!

[Source: EcoMotors]


I'm reporting this comment as:

Reported comments and users are reviewed by Autoblog staff 24 hours a day, seven days a week to determine whether they violate Community Guideline. Accounts are penalized for Community Guidelines violations and serious or repeated violations can lead to account termination.


    • 1 Second Ago
  • 51 Comments
      • 5 Years Ago
      This technology could surely have a future in tanks, helicopters, trucks and other military and transport vehicles.

      The future for automobiles is spelled electric engine.

      The cost for any manufacturer to introduce a new ICE like this, would probably be $ billions and I can't see any manufacturer, especially in these financial times, spend that kind of money when the electric car is making its way to the showrooms. I honestly don't believe we will even see the HCCI-engines any time soon.
      • 5 Years Ago
      Aslong as this technology isn't vaporware, then sign me up first. The potential for ridicolous amounts of torque in a compact car FTW.
        • 5 Years Ago
        Mike, traditional two strokes are big polluters only because they run an oil-fuel mixture. Turbodiesel two strokes are able to run a seperate crankcase because of their forced induction and direct injection, so the motor oil stays where it is supposed to and the motor is no dirtier than a four stroke.
      • 5 Years Ago
      The figures are not far out of line for a Diesel 2-stroke 4-banger.

      However, Diesel two-strokes don't work without an external compressor, usually a Roots blower. Where is it in this pic?

      And as to how the charge gets in, it's a ported engine, like other two strokes or a Wankel.

      I don't really see a point to this. A regular 2-stroke 4-banger would work much the same and has almost all the same advantages and is far better understood.
        • 5 Years Ago
        The two conn rods that are short are no shorter than in a regular I4.

        You don't need to tell me what to visualize. I get it. It just doesn't really save much, it's probably not worth the trouble.
        • 5 Years Ago
        You didn't notice that while two rods are really long, the other two are really short, and while the thing is very wide, the actual combustion area is half what an I4 would have, and thus, would only need half the water jacket, which is what the block encloses. And, as far as why use cast iron, the fact is that any material which an I4 could use, this could also use, which still results in weight savings.

        Visualize a Porsche boxer 6. Then visualize a 12 piston version of this, with three of them running in a row with the appearance of a flat 6. You have a wider version of the boxer design which is somewhat closely similar in layout, except this new design has the potential to make twice the horsepower and torque, with an advantage in combustion area size, for cooling efficiency and weight savings..

        No, it's not the second coming of the 911.. But potentially, it could be made in displacements much smaller than anything existing now, with enough power make current ICE designs obsolete. Nothing in engineering is perfect, but this has some interesting features. Recall the normal Wankel cycle engine is less than 100 cubic inches displacement.

        I am thinking this prolly would be a strong fail for motorcyclkes, though. :rofl:
        • 5 Years Ago
        I think the advantage of this is that it would be smoother.
        • 5 Years Ago
        Or you could not make the block out of cast iron. This also adds some much longer conn rods to the equation plus whatever that mechanism is in the outer pistons that looks like an oversized wrist pin. And I can't see how it has fewer moving parts than a 4-banger 2-stroke.

        regular ported 4-banger 2 stroke:
        4 pistons (plus rings)
        4 wrist pins
        4 conn rods
        1 crankshaft
        plus the blower system

        This:
        4 pistons
        2 wrist pins
        2 pseudo wrist pins
        4 conn rods (two huge)
        1 crankshaft
        plus the blower system

        I think you are failing to notice how long this thing is. If those are 10cm pistons, this engine is almost a meter long. In essence, it just moves two of the cylinders out to the end of the other two and turns them 180 degrees. They don't disappear. This motor is perhaps 10% smaller than an I4 tops, because it gets to overlap one crankcase with another. The other two end crankcase areas are their own non-shared spaces, like an I4.
        • 5 Years Ago
        Weight.

        This thing has only two cylinder sleeves and half the enclosing engine block for the water jacket. Cast iron is *heavy*...eliminating 50% of the block weight is huge. The more conventional 2-stroke 4-banger has an engine block the size of a normal four cylinder ICE, which is about twice as big as this.

        Also, if I'm looking at this design correctly, this thing is inherently balanced, which a 2-stroke 4-banger certainly is not.

        Finally, the problem for both designs is lubrication and pollution, but...hey, it makes financial sense, too...less weight equals less material cost, generally...and I bet this has fewer moving parts than a 2-stroke 4-banger, too.
      • 5 Years Ago
      This is quite old and they have been trying to sell this technology to an OEM for years. Many companies produce OPOC demonstrator engines but none have had any success. They have a stand at the SAE world congress every year, but there are much more interesting technologies right now (especially the Scuderia). There are a lot of problems with this engine that make it not feasible for a modern automobile. There is virtually no way for it to meet emission requirements. It's much better suited for stand alone power generation.

      http://www.greencarcongress.com/2005/05/fev_developing_.html
      • 5 Years Ago
      *yawn*

      Call me when one of these magical internal combustion engines is available in a vehicle i can actually buy. Been hearing this kind of crap for years but nothing materializes & our engine technology advances at a snail's pace..

      • 5 Years Ago
      Fairbanks-Morse 38ND8-1/8 Opposed Piston Diesel Engine.

      A 1938 design that has been in service since, and these big boys produce well over 1,000 horsepower at 720 RPM.

      As someone else stated, "it's not vaporware, it's proven, reliable, simple technology."

      What has been will be again.
      • 5 Years Ago
      D@mn!!! 325hp and 664lb-ft!!! That's awesome! Why did I think of that??? I'd love to see it in action.

      It's looks like it's as simple or more simple than the rotary engine. Less moving parts, less weight, lots of MPG and power. What more could you ask for??? I love new technology, especially when it's under the hood.
        • 5 Years Ago
        Sure, it sounds great, but I'll get excited about it when I see it in production
        • 5 Years Ago
        The basic idea has been around for a while http://en.wikipedia.org/wiki/Napier_Deltic =which is my favorite engine ever just because of how odd it is.... cant wait to see this in production
        • 5 Years Ago
        I saw a video of this technology about a year ago. It was developed as part of a DARPA project for next-gen diesel engines for helicopters. The engineer gave a brief Q&A about the engine. Basically, its a modular application that can be adapted to almost any fuel and was designed to be boost flexible. The major advantage is that cylinder deactivation completely removes the cylinders from the systems so they are no longer dead weight and friction while remaining perfectly balanced.


        Link to the video:
        http://engineeringtv.com/blogs/etv/archive/2008/07/01/opposed-piston-opposed-cylinder-engine.aspx
        • 5 Years Ago
        I hope you don't think those diesel number are naturally aspirated.
        • 5 Years Ago
        Yeah, it is one of those things that make you go "Why the hell didn't I think of that?!?!".

        Of all the recent engine technology concepts that I have seen over the last couple of years, this by far makes the most sense.

        I don't know though, if Autoblog is correct in saying that this is a 2 stroke engine.....

        Hey OEMs... jump on this tech and lets see some 2 cyl beasts. I wonder how high this thing can rev, and if it will take to boost?
      • 5 Years Ago
      In real terms that would be 900 Nm.
      • 5 Years Ago
      So as far as I can tell, the sole improvement over the opposed piston designs we've had in submarines for decades is that this is all tied to one crankshaft? I mean, it's definitely good for weight but putting two LONG con rods on the pistons at the ends is certainly going to offset that advantage almost totally. You won't have the conrods operating in air so that means you'll have much more engine than that picture lets on for all that extra crankcase.

      Also it's gonna be a hugely out of balance engine because while the same sized conrods will be opposed in their reciprocating movements, both of the big conrods will be on the same side. This is gonna make it run about as smooth as a truck from what I can tell. Correct me if I'm wrong since harmonics is not my strongest suit.
      • 5 Years Ago
      The opposed piston mechanical design of this engine is not new, except this one is horizontal and is of boxer layout . The opposed piston patent for a diesel engine was taken out in about 1910 and Junkers in Germany made the first engines with two crankshafts for aircraft use. Many early very large two stroke marine engines used the opposed piston concept either with twin crankshafts or one crankshaft and long external connecting rods, All versions need a supercharger or turbocharger. This one uses external rods and the increased size and inertia of those will limit maximum revs over a version using two crankshafts. Therefore the power density is not as great of that using two crankshafts. The opposed piston arrangement does give a very low level of balance vibration although the two cylinder arrangement will cause a large torque reaction when each cylinder fires. There would be a more even pattern of torque reaction if the engine had more rows of smaller cylinders for the same power. The only way to minimise the effect of the torque reaction is to use a higher inertia flywheel which adds weight. The pistons are timed so that one piston times the inlet ports and the other times the outlet ports, in other words the two pistons do not reach top dead centre together, one is in advance of the other which results in a small out of balance couple.
      The scandinavians and europeans have produced many versions over the years.
      In Britain the Napier Deltic, triangular construction with three crankshafts, the most compact power to weight diesel engine ever made for marine and railway use, Doxfords of Sutherland single crankshaft in line marine engine and the Commer Roots truck engine come to mind. In the US the only one I can think of is the Fairbanks Morse twin crankshaft version used a lot by the Navy.
      The achilles heel of the opposed piston design is exhaust piston temperature which limits power output per cylinder.
      Current thoughts are to use opposed piston designs for small aircraft, probably pilotless drones. Maybe this is where this design started from, because it will need a lot of development before it is put into civilian private use.
      George
      • 5 Years Ago
      That is a really neat idea, but I'll wait till I see a working prototype.
      • 5 Years Ago
      Hmm! Looks like the pistons work equally against each other.

      Equally opposing forces mean...this thing is going nowhere!

      Just a guess! I'm not a big Pop Mech's futurism fan!

      Jonny, spell check that second sentence!
    • Load More Comments