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.

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

Durability and complexity are always my concern with these too. I'm curious to see how they do after a few years of actual use in a vehicle.

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...

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.

sometimes, the solutions comes from the places with simplest of demands

Of course, but some segment with a higher profit margin could lead to a quicker return of the investment on research and development. Anyway, since their design is originally meant to be fitted in horizontal position, that would lead to a good market opportunity in aviation.

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.

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