4-stroke opposed-piston engine development from Pinnacle Engines?
They claim their target market is Asia, focusing on scooters and the highly=competitive 3-wheel utility vehicles market in India. Their concept seems interesting, and maybe it could succeed, but it's been under development since 2007 and, after some delays, a production version of the 110cc scooter engine seems likely to start in November 2017 in India. Larger-displacement versions with more cylinders are under development too, intended to the automobile market, even though their horizontal layout keep their applicability quite limited to longitudinal-engined vehicles. But anyway, even though American automakers are not so receptive to technologies developed by third parties, it's likely to be one of the ways to meet more stringent EPA/CAFE requirements.
http://www.pinnacle-engines.com/ |
I've always thought opposed-piston engines had some inherent efficiency advantages and have been puzzled by their lack of penetration into the smaller engine market.
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As they say, if it sounds too good to be true, then it generally is not true.
Sleeve valves have always had sealing and durability issues and the opposed piston concept has too many moving parts for low cost production. Interesting that it is partially based in India... Simon |
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400 hours sounds like a lot of testing... but if you average 30 miles/hr that comes out to only 12,000 miles. A typical modern car engine can be expected to run 5000 hours or more. So, it's interesting, but I'm skeptical that it will make the cut, long-term. |
well, they laughed at hybrids when they came...
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What did surprise me about this engine is the 4-stroke cycle, while all other opposed-piston designs are 2-stroke. Anyway, even though it seems to have some realistic possibilities to find its way into the market, what makes me quite skeptical is the focus in some market segments with a lower profit margin.
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sometimes, the solutions comes from the places with simplest of demands
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An interesting idea that crops up every so often. The brits had this fantastic sounding 3 cylinder, 6 piston, 2 stroke diesel engine locomotive, with a bunch of turbos. It sounds fantastic.
Pollution was problematic, so they went away. Here's a model that illustrates how it works: https://www.youtube.com/watch?v=ywuNd51ec6I Here's a video that really captures the sound of the Napier Deltic engine: https://www.youtube.com/watch?v=1xohNl7iB2o Sometimes known as the whistler engine. |
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I saw one in a museum a couple of years back, I don't think the lack of cylinder head heat losses, can overcome the disadvantage of all that extra complexity.
http://ecomodder.com/forum/attachmen...1&d=1481904280 |
I fail to see how Pinnacle motor is any different than any other flat engine.
The design was create in 1896 and is used today in a few cars such as Porsche and Subaru https://en.wikipedia.org/wiki/Flat_engine#Current_users |
Opposed piston is not the same as flat.
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A flat engine like my old Corvair has pairs of pistons with the crankshaft between them. The Pinnacle has two pistons crown to crown in a common bore each attached a separate crankshaft.
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We had these for back up power on our Nuke Subs, Fairbanks Morse 68 8 1/8 ND. I went to school to learn how to work on em. You'd have a hard time getting one in a Honda, since it's bigger than a Buick and weighs 60,000 lbs or so. It would likely overtax the suspension.....
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Leno will do it.
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The website is lacking basic information, so I went to Google images. Next Big Future: Pinnacle Engines opposed-piston engine could have 30-50% more efficiency by 2013 http://3.bp.blogspot.com/-zWNEF_qBxy...nnacleopoc.png https://dreamer3000.wordpress.com/op...nacle-engines/ https://dreamer3000.files.wordpress.com/2011/04/03_.png GIF Silicon Valley Firm Pinnacle Working on Classically Insane Opposed-Piston Engine | Car and Driver Blog http://blog.caranddriver.com/wp-cont...cle-Engine.gif TEN WAYS TO IMPROVE GAS MILEAGE TO MEET PRESIDENT OBAMA'S PROPOSED NEW 54.5 MPG STANDARD FOR 2025 VEHICLES - PBT Consulting http://tommytoy.typepad.com/.a/6a013...ef5d970b-550wi |
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how smooth is this design, anyway? :D
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I'm not sure if i'm missing something but it would seem that the engine would be less efficient. Looking at the animated pictures above that would just be a high compression 3 cylinder with twice the rotating mass since it has two rotating assemblies. Other than possibly starting possibly being quicker and revving faster I would think a high compression 3 cylinder would be more efficient.
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Thermally quote efficient, but intertial and frictional losses from 2 x cranks and the gear required to synchronise them will be significant. I suspect there's a reason why such designs have never been mainstream.
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The opposed-piston layout used to be mainstream for interwar German aircraft, but it was mostly Diesel and 2-stroke. Anyway, considering that a regular 4-stroke also has some inertial and frictional losses from a conventional valvetrain, the dual-crank setup might outweight this perceived disadvantage.
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Indian company Greaves Cotton, one of the largest independent engine suppliers in India, set a deal with Pinnacle Engines to develop that opposite-piston layout and put it on production. Not sure what would be the first product to feature it, but since many tricycle factories in India resort to Greaves engines it's likely to succeed.
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Last updates I found were from February. Seems like most of the focus will be toward using this engine with CNG, which is a widely popular fuel in India.
https://www.youtube.com/watch?v=puWIOnCTuSg http://www.greavescotton.com/php/med...fd4ce602ef.pdf |
From that video looks like some rebranding of catch phrases involved.
I wish them luck. |
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Mazda?
I heard recently about something like this, I believe it was Mazda that was experimenting with it. The efficiency was supposed to largely come from the fact that it can run on duel fuel. It's supposed to have a tank for diesel, and one for gas. Depending on engine speed, load, and temperature it's supposed to adjust the mix (and it runs on the diesel ignition cycle regardless). Supposedly It can also run on strictly one or the other, but it's optimum would be while running both.
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These guys signed on with cummins and a couple others for 10 of millions of dollars. Should see some within a couple years. The average efficiency across the entire operating range is phenomenal. Thought they died a couple years ago as I remember reading an opoc article from popular mechanics with them in 2012.
https://www.youtube.com/watch?v=usmauFigpzk |
I used to be the general manager for a municipal utilities. We had 2 Fairbanks Morse OP motors they were 24 piston 12 cylinder. Had 8 1/8" bore and 12" stroke on each crankshaft. The bottom piston uncovered the intake ports and the top piston had the exhaust ports. It ran off of a big roots supercharger to get it going The exhaust port opened a bit before the intake to start the scavenging process. Once going a turbocharger would come on and pressurize the intake of the Roots letting it freewheel reducing drag.
The pistons were dished making a nearly perfect spherical initial combustion chamber. The motors were put in in 1960 and by the time I was there in the early 80's they had been run down. Our municipality was in a buying group and the group paid us to keep the group usage lower during peak times. I took our board up to Beloit Wisconsin to tour the fairbanks factory to discuss the rebuild and to tour the factory. The OP motor was made without castings. It was also used in a 9 cyl supercharged only version for nuclear submarines. |
Would this approach be any different/more efficient than having a conventional in-line engine where two pistons share one combustion chamber?
Then again, what would the difference between that and just one big piston? Tired brain, this not make sense George... |
No heat loss through a cyl head; more of heat energy applied to a "working" component.
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Gasoline engine through and through. |
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I would think it's a case of capturing more of the expanding gasses force...which you could do with a much longer stroke. Of course it wouldn't rev worth poop, and have to deal with more side forces, but whatever... |
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Part of the diesel efficiency comes from running higher btu content fuel. Gas has lower btu than #2 diesel
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