Miller cycle / Atkinson cycle

[89acclaim]

Has anyone else though of increasing the efficiency of an engine using them? If you don't know what they are.
http://en.wikipedia.org/wiki/Miller_cycle
This is a good research paper done on it.
http://society.kisti.re.kr/~Eksae/_notes/data/pdf/v2n1_1.pdf

Using an idea like this you wouldn't be for all out power. It would bring the power output per displacement down. I think it would be neat to play around with this on a 2.5 tall block. Use some flat tops and a milled deck to bring the cr up to 11 to 1. Delay the intake valve closing to around 90 deg BTDC to make the dynamic compression ratio 7.1 or so. To increase the power output per displacement you could run forced induction. Anyone have any thoughts, could be a fun little project.

Daniel Merrill

[altered7151]

You're going to see a resurgence of old ideas applied to internal combustion engines here in the near future. There are quite a few concepts out there that either were not possible, very difficult to operate, or very inefficient to run in the past. But now with the advancement in computer engine management systems they are becoming a reality. I just read an article in a trade magazine a couple months ago about some guys that are doing alot of research on sterling cycle engines and getting awesome efficiency out of them. There's some cool stuff coming on the horizon, especially with the price of gas, everyone is trying to build a better mousetrap.

[87glhs232]

One of our mechanical engineers at work built a motorcycle and rode from California to Florida on one tank of gas. No...he wasn't towing a trailer of gas either :p

[89acclaim]

There's some cool stuff coming on the horizon, especially with the price of gas, everyone is trying to build a better mousetrap.

II agree, I guess I am an odd kid for fun I used to wonder around theoldone.org and http://naca.larc.nasa.gov/ all sorts of fun research papers and ideas on there.

It would be neat to make an engine that would use the miller cycle with variable cam timing. So that it you would be able to change the dynamic displacement of the engine as load requires. Combine that with a efficient DOHC head, VNT turbo, and a "cold" egr / leanburn setup and you could have a very fuel efficient engine.

87glhs232 do you know if he did a diesel conversion? I remember a guy around my area doing a diesel conversion to a Harley and running it on vegetable oil. Myself I like biodiesel more than converting to vegetable oil

Daniel Merrill

[Putter]

Atkinson cycle engines are already out there, Hyrids use them.

I think Crower's new idea of a 6 stroke looks very promising. Do a google on it.

[89acclaim]

Yeah I noticed the Toyota Prius and the Ford Escape use the Atkinson cycle. I like The Miller Cycle more forced induction .:nod:

The 6 stroke setup looks ok for fixed applications like power generation it would be bulky at least at the beginning. It also looks like it would be low rpm bound. The constant heating and cooling of the parts is an interesting obstacle.

The idea of "mechanical octane" and quench is an other interesting to me, that would be fun to try in a 2.2/2.5.

Daniel Merrill

[mcsvt]

One of our mechanical engineers at work built a motorcycle and rode from California to Florida on one tank of gas. No...he wasn't towing a trailer of gas either :p

I would like to know more about this as well. Does he have a webpage? I remember seeing somebody put a VW Turbo Diesel motor into a motorcycle. That would be interesting. :eyebrows:

[Turbodave]

Didn't Mazda have a miller cycle engine available in the 90's model Millenia's. Was a supercharged V6 from what I recall.

[mcsvt]

Didn't Mazda have a miller cycle engine available in the 90's model Millenia's. Was a supercharged V6 from what I recall.

Yup the Millenia S. I have heard they are no fun to work on, generally speaking.