Quote:
Originally Posted by ProDigit
Curious about a Wankel engine...
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And I'm curious about a basic two-stroke, when it comes to extreme ecodriving by Burn & Glide. The most basic two-strokes with piston control induction, no variable exhaust port and no fancy fuel injection is in great need of distinct pressure waves to give maximum power and something you may (at best call) fuel efficiency. My unproven theory is that such a simple two-stroke have a much steeper drop in their BSFC-map below WOT. So perhaps a vintage car with a two-stroke engine can have an even larger inprovement than a 4-stroke by performing B&G/P&G. I hope to try this when my Saab 96 1964 replica is finished (which may happen any year now...)
The Wankel is an interesting design, partly related to the two-stroke engine. They are infamous for high fuel consumption, which I think comes from the long and narrow combustion chamber that gives a poor ratio between surface and volume. (high heat loss) I think the Wankel's comparable to a regular 4-stroke piston engine when it comes to pumping losses. I don't know how they compare with friction losses, but I guess their efficiency may drop steeper on low revs because of heat energy losses from the poor combustion chamber. So perhaps a wankel can be more efficient than a 4-stroke piston engine on higher revs? At realy high revs I guess the wankel also can benefit from the lack of restricting valves. -When the ports are open, they ARE realy wide open!