Porsche applies for patent of 6 stroke engine

[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!