Miller-Cycle strategy using twin screw SC and renesis?
 

Hey, would it be possible to get some sort of Miller-Cycle type efficiencies with this SC on the renesis? If I remember right the Mazda Millenia S had a 2.3L Miller-Cycle engine with a twin-screw SC. Maybe someone with more knowledge on this subject can enlighten. I know most people will just want maximum power, which you will probably get by not using the Miller-Cycle, but some people like to save on gas (plus I think Miller-Cycle reduces the chance of detonation).

I'm not an expert, but I believe the Miller cycle involves significantly different timing on port opening and closing. Since the port timing on a Wankel is controlled by the location and size of the opening in the side of the rotor chamber, changing the timing would involve redesigning and replacing a good portion of the engine. In otherwords reguardless of whether a Miller cycle rotory would be a good idea, only Mazda would ever have the development dollars to do it.
--R.

A description of the Miller-Cycle at www.howstuffworks.com

The standard four-stroke engines described in How Car Engines Work are called Otto-cycle engines. They are named after Nikolaus Otto, who invented this type of engine in 1867. In the same way, Diesel-cycle engines are named after inventor Rudolf Diesel.

Ralph Miller patented his Miller-cycle engine in the 1940s, and for the last several years Mazda has been using this type of engine in some of its cars.

A Miller-cycle engine is very similar to an Otto-cycle engine. The Miller-cycle uses pistons, valves, a spark plug, etc., just like an Otto-cycle engine does. There are two big differences:

-A Miller-cycle engine depends on a supercharger.
-A Miller-cycle engine leaves the intake valve open during part of the compression stroke, so that the engine is compressing against the pressure of the supercharger rather than the pressure of the cylinder walls. The effect is increased efficiency, at a level of about 15 percent.

A miller or atkinson cycle engine is where you have an expansion volume which is effectively larger than the intake volume. On a piston engine you can do that with valve timing, letting the gas flow backwards through the intake valve, or with a wacky crankshaft setup.

I'm not sure how you'd do that on a wankel. You can't change the shape of the rotor or engine block. Maybe you could have the intake port open later, or have a third port during the compression portion that bleeds off pressure.

Or there's always the wacky non-wankel atkinson rotary shown on wikipedia:

http://en.wikipedia.org/wiki/Atkinson_cycle

http://white-smoke.wetpaint.com/page/Rotary+Engine

The miller cycle was tried on the rotary. They used an additional intake port at the 12 o'clock position on the rotor housing. This had a valve in it that fed it back into the main intake system. This valve was timed to open and close as needed to keep the intake open for longer than the exhaust.

That Atkinson Cylce Rotary looks very cool!

What happened with the Miller Cycle? You said it was tried. Did it work? Explode?

Cheers

Andrew

New bump.

Anyone heard from Hymee?

The Atkinson is being put in production model cars

http://peswiki.com/index.php/Directo...ralato_Ruggero

http://www.globalautoindex.com/news.plt?no=1691

Its Hybrid electrical and Atkinson rotary car. Really, really COOL! Why the hell mazda has been screwing around with a Hydrogen RX-8 that nobody will buy or can afford at this point is anybody's guess. Ford sure does not have the extra money to be playing with crap they can't sell. But a hybrid electrical and rotary hybrid can be sold.

Toyota seems down with getting a piece of the Atkinson action and has a hybrid that uses this technology.

http://www.edmunds.com/insideline/do...d=109049?imw=Y



Anyway, wished Mazda stop being nuts and get with guys like Hymee, Pettit, the AFSC, etc.... and make an official Mazda supercharger for the RX-8. It's so damn obvious that it would sell as an option for the RX-8.

Wow, that Atkinson cycle is something else.

I dunno, looks to me like a major pita to perfect. To many detailed little creepy niknaks and doodads to get (keep) just right, not to mention having to seal-off leakage. That slider scares me. I hate sliders... Just imho, sorry... I think I like piston engines better...

Anyone hear from Hymee? Or perhaps Hymee himself might supply us with an update?

he is still around .
The lack of updates here does suggest that this particular project is not going anywhere at the moment however.

i chatted with him about two weeks ago.. he is recovering from an illness.

beers :beer:

i dont care about the sc, he need to get healthy. best of luck man

Did he make it back OK?

The main difference between an Atkinson Cycle and a Miller Cycle engine is forced induction. Miller cycle uses it. On both accounts you make less power than conventional timing. The key to it's use are lower emissions and better gas mileage. Don't be looking at either as a way to gain power though.

Yeah - I'm still here. Been tending to other issues for a while, but this project is moving again. I've invested to much to give it away. I've got some goodies instore, but I'd rather wait until I have something more concrete other than some CAD drawings before I let any secrets out of the bag.

The best way people can help support this project is to continue to support my existing high quality products.

Cheers,
Hymee.

good to see your back hymee!

Welcome back Hymee . You have been missed ....

hey there hymee, i once i get my carputer up and running im gonna get your scanner

Welcome back

Great to see Hymee back. I was very interested in his supercharger.... but, more importantly, good to see his health is somewhat restored.

hymee.

you have a email at pre designs.


and nice to see you posting again.

beers :beer:

Welcome back Hymee. We missed the color you added around here!

oh man. i just finished reading this entire thread. it's so much like a roller coaster that let's you down by ending.

here's a couple q's.
Isn't pettit's sc twinscrew? I'm curious about the differences between theirs and the hymee. Living in florida means that pettit is likely a better option for me, but hymee really seems to know his stuff, and he's had this thing in r and d for over 2 years now. pettit probably could use some more r and d.

i just want a bolt on and forget it sc so bad. please make it happen for me, hymee. i really liked aus when i was there. too bad you guys spend all your time with telescopes watching the kiwis hump sheep. ;) lol.