Nateb123

I have a couple fairly vague but interesting ideas that I'd like to run by the folks who really know engine theory. First off, I'm wondering about the effect of putting a little piece of metal (maybe a pin, though likely more purposefully shaped) in the way of the intake charge just before it enters the working chamber. It would act like the aux ports do except it would pop up at low RPM and close at high RPM. It would be located in the housing and so would pop out perpendicular to the charge as it enters the chamber. This would cause the charge to homogenize more effectively without direct injection and would mean a better BSFC for the engine. Anyone know some basic aerodynamics that could help me figure out a particular shape?



Second, the apex seals are obviously the biggest problem with wankels right now and the next biggest is the surface area to volume ratio of the combustion chamber. By creating apex seals that are stronger, the pressure could then be increased allowing the use of diesel fuel as well as rotors which are more triangular. This would mean more volume and less SA which would mean MUCH better fuel consumption and torque. I've heard about L-shaped apex seal designs (which use pressure in the chamber to force the seal down) but haven't found much in the way of real papers regarding them. I'm trying to work out how a seal could be designed so that it not only uses the pressure of the exhaust and combustion stroke to create a better seal, but also uses the lower pressure of the neighbouring chamber. Can anyone point me to an SAE paper about apex seals?



Also if anyone has any comments or suggestion regarding the ideas, go ahead and post them up. Thanks.

Nateb123

Bump. Just thought I'd add that the T-shaped apex seal would also be less prone to wear because it wouldn't need to lean, and less likely to break under detonation due to greater mass.

Lynn E. Hanover

The current design is close to replicating the life of a piston engine. The seals using pressure of compression and power stroke to help them press against the surface to be sealed, was Wankels real contribution to the program. The current layout was a choice made by NSU. Wankel got pissed off and left the project.



So the current seals do that already.



The excessive surface ratio is in a small way being addressed by the X-16 engine by going back to the 12A rotor width, and increasing the stroke. Higher pressure direct injection into the chamber after the intake port has closed should improve

atomization and reduce HC.



The next logical step would be to ceramic coat the rotor faces, so less heat is lost to the oiling system. Work continues on a reactive bed to reduce NOX, so that higher compression ratios can be used. So things are moving along at a slow pace as a result of the very small production numbers Mazda always works with. They do put a high percentage of income into research.



You are not alone.



Lynn E. Hanover

Nateb123

Thanks for the feedback Lynn, always good to hear the views from someone experienced unlike myself.





I read on the freedom motors site (the folks who make vapourware Wankels for Moller) that they had developed a ceramic with NASA which fixed that problem. Still they're tight-lipped about it which either means they don't want Mazda to know, or they're full of crap. Once Mazda does though, I imagine rotaries are going to be able to give turbine levels of power. Coat aluminum instead of cast iron rotors and you'll get more power and tons more revs *drool*. Can't wait for that.

master_visionary

hey maybe if we modified the rotors deep spots to be shallower that would create a smaller combustion chamber ..??..??..??..? and if we also biased the depth towards the front of the combustion chamber it would create more push resulting in more torque.