interesting engine

Sorry, but the reciprocating engine has enough moving parts already. This is overkill, and would have some serious losses, I would think. Gimmie a single piston per journal/per jug any day.

The wankel is the epitome of internal combustion engine. That is, of course, unless you can get jet turbine engines in miniature form.

I'd like to see this engine maxed out for a drag race motor. Then see how long the thing would last. I'll bet that it has a high maintenance schedule. Way overkill. Way expensive. Likely be way problematic too.

Opposed piston engines have a long and successful history -- look up the Junkers Jumo for an example.

Most of the successful ones that I know about use two crankshafts, with a few oddballs that use one crank + linkages. The linkages shown in that picture would be highly problematic, IMHO.

Note, too that opposed piston engines have a long and successful _history_ -- if there are any still around I don't know about them. They were hot shit for airplanes and stationary engines back in the

1940's, but they faded off the scene with the advent of the turboprop engine*.

Like all engines, if you ignore the Wankle's special shortcomings and pay attention to the special shortcomings of its competitors, it's a better engine. But if you ignore a reciprocating engine's shortcomings it's a way better engine than the Wankle, because it has no apex seals to wear out. If you ignore the gas turbine's fuel efficiency and exotic materials requirement it's better than anything else because of it's power density. Etc.

So each engine must be weighed on its own merits. I suspect that -- given how many different engine types have been tried, and have failed or only been marginally successful in the market -- than in a car the reciprocating engine is probably the best way to turn fuel into mechanical energy using hot fluid as an intermediate medium. If that weren't the case then you wouldn't see it dominating the market.

• Which is an interesting case study: a turboprop engine is less fuel efficient than a piston engine. But it's just so much lighter that when you put it into a plane with enough extra fuel to equal the weight you just saved by swapping out the piston engine, you can fly farther.

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The upper piston thing eliminates the valve train, so it's a wash at least on complexity. It's intended for efficiency, not drag racing. Drag engines aren't efficient and they don't last long.

John

Few of those "new and innovative" "green" engines are doing anything newer than rehashes of basic concepts that were tried and abandoned* before 1910.

You could probably make an industry out of resurrecting old patents for engines, painting the prototypes green, and extracting investment money (not to mention government grants) from starry-eyed rich people with too much cash, not enough grounding in basic mechanics, and feelings of environmental guilt.

Once you get past "suck squeeze pop phooey" there's not much fundamental change you can make to an internal combustion engine.

• Or that spectacularly failed in the open market.

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Opposed piston, two cycle diesel engines were the mainstay in most WW2 subs.

Tench class had FB-Morse 9 cylinder, 18 piston diesel putting out 1600 hp at

720 rpm.

Neat engine.

Tm

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AFAIK they were sorta-kinda the same idea as the Junkers Jumo -- opposed pistons, running somewhat out of phase, with ports on the cylinder walls. How the pistons were driven was the big difference, with the two main competitors being one crank + linkage, or two cranks + gearing to synchronize them.

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IOW it's the Junkers Jumo concept with the twin cranks and their difficult mechanical coupling replaced by a single crank and a difficult mechanical linkage to the outer pistons.

And it has the added feature that the linkage to the outer pistons is placed in a way that makes it hard to add two more cylinders, and damn near impossible to add more than that. Ooh -- clever.

_Not_ a thrilling new idea. Just a rehash of an old one. Maybe a good rehash of a good old idea (the opposed-piston engines had a long and successful run in the marketplace), maybe a bad one, but a rehash none the less.

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ady.

n c n

Well it comes down to cost of manufacture for the masses as well. We do not have turbine engines because they are cost prohibitive. Wankel apex sealing has vastly improved ovr the first generation engines that actually made mass production numbers. The new Mazda has one model that uses the new rotary, but I think it is all but dead if that model does not survive the eco-crunch.

A two stroke model airplane engine with a glow plug and no rings would seem a pretty long term reliable design.

Two stroke Harleys? Heheheh...

I want a tiny motor that runs a recharger for my ELECTRIC motorbike. At least then most of what I put in, I'll get to use with minimal waste.

Sorry, but the opposing piston mechanics far outweighs valve train mechanics, and I could make it a two stroke diesel for that matter. As far as the darg race engine remark goes, you refer to top fuel classes where engines last less than ten runs. I refer to the PEOPLE's classes of drag racing where they PROVE or DISPROVE a car makers capacity to build efficacious, long lasting motors.

I'll take one-slug-per-jug any day over that re-hashed, overkill 'implementation'. It was great for large,fixed industrial applications, which had maitenance teams behind them, and I do consider the submarine platform to be 'fixed' in that sense.

Consumer motor vehicle applications would never support such a motor design unless it can do

100,000 low maintenance miles, which is the current warranty standard.

Then give it to the drag race boys for final proofing.

snip

I like 'One-Slug-Per-Jug'.

The expansion is only good for slightly less than half a crank rotation anyway. I do not see the extra slug doubling performance on a per cubic inch/per cylinder rule. It seems to me that there is actually a cost in reciprocating mass alone that rules it out.

We strive to make that as low as possible. Doubling it (or more) without a coinciding doubling of the power stroke's output seems counter-productive to me.

He (the site)also mis-defined what a two stroke engine function is.

Two-cycle engines have always interested me, although this one isn't simple like my Yamaha 250 was.

John

The Junkers Jumo went into a number of successful airplanes.

But of course they also had those maintenance teams. It's amazing what you can do with a piston engine when complexity is no barrier.

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Tim Wescott
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At least the ones that use the Day cycle* are. They're kind of like regenerative receivers in the RF world -- very few components at heart, with each component carrying out more than one task. The design is superficially simple, but because of the interaction of all the parts actually wringing good performance from the system involves a lot of hard thought and outright tinkering.

• Day was the one who invented the crankcase-pumped 2-stroke engine.

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Tim Wescott
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When all they can show is rendered 3D models you know it is all just bollocks which had a green label stuck on it to attract venture capital.

So much easier and safer sticking with computer models instead of building something which will demonstrate you are only getting half your claimed performance for a few hours before it falls to bits.

Aha! It's used in the Audi A3 ?:-) ...Jim Thompson

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           Only as good as the person behind the wheel.

Wow, a two-cylinder radial engine.

Cheers

Phil Hobbs

-- Dr Philip C D Hobbs Principal ElectroOptical Innovations

55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net

As a two-stroke, it might be enough to run a compact car. They claim

1.1 HP per pound.

My first wife had a Kawasaki 500 three-cylinder two-stroke bike. 0-60 in 4 seconds, if it didn't seize up or go unstable and toss you into the weeds. She lost her spleen on that one.

John

No balance shaft? :D

Ouch.

Michael

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Audi has been using VW engines, are they changing?

Cheers