[Murf the Surf]

Interesting: I cam across this on line.

Porsche has filed a patent for a strange (and possibly brilliant) idea of a six-stroke combustion engine.
Right now, most ICE are 4 stoke: intake, compression, power, and exhaust.
Porsche reckon they can add another compression and power stroke to this process. The patent describe this as "six individual strokes that can be divided into two three-stroke sequences." The added steps would occur between the traditional power and exhaust stroke. The first sequence, then, would be intake-compression-power, followed by compression-power-exhaust.
Porsche's patent shows a crankshaft spinning on a ring with two concentric circles—an annulus. This alternates the center point of rotation, effectively lowering the piston's travel (bottom dead center) slightly for the added strokes. That in turn changes the compression, since the piston isn't traveling as far up (top-dead-center) in the cylinder. And that also means this engine has two top and bottom dead centers.
This design has the potential to generate more power with better efficiency. In a typical ICE, only one stroke in four actually makes power. This changes the formula to one stroke in three, and it also burns up the mixture more thoroughly. The downside is added complexity. Whether the gains are enough to justify the design remains to be seen.
As with many patents, it's possible this could never see the light of day. It's certainly an interesting idea and I guess shows Porsche is trying really hard to keep the internal combustion engine alive.

[Efthreeoh]

I would think the additional friction of the annulus ring would offset any efficiency gains? Thoughts?

[Murf the Surf]

Originally Posted by Efthreeoh

I would think the additional friction of the annulus ring would offset any efficiency gains? Thoughts?

I'm not an engineer and generally live by a few simple rules and mostly common sense. I would think that adding this much complexity might defeat any advantage. Having said that I suspect the engineers at Porsche have done some maths on this thus the patent application.

[DrVenture]

You said "annulus", heh, heh!

[RM7]

Originally Posted by Murf the Surf

I'm not an engineer and generally live by a few simple rules and mostly common sense. I would think that adding this much complexity might defeat any advantage. Having said that I suspect the engineers at Porsche have done some maths on this thus the patent application.

It's also not uncommon for companies in certain segments to patent every and anything under the sun they can. It's not so much about future production plans, but more about winning the "patent war". Often times they will patent stuff they are not serious at all about. But every once and a while one of those ideas will be fruitful in the future with further development.

[Chihuahua]

Originally Posted by DrVenture

You said "annulus", heh, heh!

That was cool. uh huh huh huh huh.

[Dégoûté]

So would revs get really high or really low?

[Efthreeoh]

Originally Posted by Dégoûté

So would revs get really high or really low?

I would think lower revs. Interesting question though, how the design would affect the harmonics of the flat-6 architecture.

[Murf the Surf]

Porsche witchcraft.

[Efthreeoh]

Not the lightest connecting rod made... and that annulus is on the wrist pin side. Hummm...

[Murf the Surf]

Illustration/animation

https://www.facebook.com/reel/1103697478215401

[freakystyly]

It has 2 min and 2 max positions on the stroke... Looks like those are exhaust ports at the bottom of the stroke at UT' UT"? Pretty interesting stuff.

[BlkGS]

Let's think this through.

After the first "power" stroke, instead of.opening the exhaust valve, they're pushing down to the lower limit, which exposes another set of intakes (possiblly not valved) which is somehow going to force its way into the combustion chamber, and then be reignited. So really, what they're doing is skipping an exhaust stroke.

That lower air intake is gonna get NASTY carbon build up. It's never going to experience anything other than dirty air, intake air, and likely oil. Unless they put an additional injector in for cleaning those passageways.