Two Stroke Engine Design

I was wondering if anyone on here has any experience designing two-stroke engines? More specifically the cylinder/port configurations. I'm a university student doing a motorcycle and engine design degree and will be starting to design a 500cc two stroke single cylinder engine for my final year project. If there is anyone in the industry or has taken on this type of project I would like to learn about the design steps taken from start to finish as designing a good performing two-stroke is a bit more complicated than a four stroke. My main concern is getting the port configuration right and being able to predict the outcomes of the configurations before they are made. With so many variables to account for anything beyond a 1D gas dynamics model gets complicated pretty quickly. CFD could certainly be used to look at flow characteristics and possibly the scavenging efficiency if a CFD program with a moving mesh was utilized. Thanks for reading and I look forward to hearing from anyone with insightful information.

Look for the sub-fourm further down the list called IC engines. Plenty of info to browse through on two-stroke engines, and if you have questions you should ask them there.

Mark

There is a great software simulation program called Engmod2t that is really good at predicting all you need.

Gary

There are quite a few good books on two-stroke engine design. One is published in /from Queens University Belfast, Ireland. I gave mine away and can't remember the author.

That book had a program included to produce typical port timing etc. Also had pipe design criteria for "tuned exhaust".

Dick Z

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Originally Posted by RICHARD ZASTROW

There are quite a few good books on two-stroke engine design. One is published in /from Queens University Belfast, Ireland. I gave mine away and can't remember the author.

That book had a program included to produce typical port timing etc. Also had pipe design criteria for "tuned exhaust".

Dick Z

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Yeah, I know the one. The one you're thinking of is "Design and Simulation of Two-Stroke Engines" by Gordon Blair. I've got some programs similar to his that I've been using.

I appreciate the info so far and will look into the EngMod2t software. I was hoping to get lucky on here and maybe find someone with industry knowledge on the subject perhaps from Rotax, Evinrude, etc as I'm very curious as to what they use for simulation tools.

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Originally Posted by HPbyGD

There is a great software simulation program called Engmod2t that is really good at predicting all you need.

Gary

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Thanks for the info. EngMod looks a step up from the TSR software that I have. Do you have first hand experience using EngMod and would you care to elaborate on it. I've checked out the website but wouldn't mind hearing your experiences with it if you've used it.

The QUB stuff was by Dr Gordon Blair I think. The Engmod2t stuff I am just learning but there are some really smart guys that I know of that use it. It is a definite step up from the TSR stuff which I think was based on the work by Blair at QUB ! One of the really big grips I always had with Tom at TSR was that he wasn't much help. Engmod2t is a sim program that will give you a LOT of info but also takes a while to learn. You can change any parameter from the pipe to ports to carb or anything in between and run a sim and see what the results will be. It is really fun to just throw things at a motor and see what it predicts the results will be. There are some really good forums on two strokes that you can find and get a lot of good info from also.
Here is a forum Pit-Lane.Biz : forum MotoGP, Moto2, Moto3, 125cc, SBK, 50cc, FSBK that has some really intelligent guys on it. Some of the posts are not in English but you can find quite a few that are. There are some post on an engine that has two exhaust ports that almost completely around the cylinder and the transfer ports are below them and also go completely around the cylinder.

Gary :wave:

Gary

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Originally Posted by HPbyGD

Here is a forum Pit-Lane.Biz : forum MotoGP, Moto2, Moto3, 125cc, SBK, 50cc, FSBK that has some really intelligent guys on it.
Gary :wave:

Gary

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Thanks for the link, that forum is great. The Google webpage translator does wonders!

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Originally Posted by PVO

I was hoping to get lucky on here and maybe find someone with industry knowledge on the subject perhaps from Rotax, Evinrude, etc as I'm very curious as to what they use for simulation tools.

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Hello,
I don't want to burst any bubbles, but having worked in Automotive OEM design facilities, the odds of getting anyone currently working for one of those names to come out here giving away secrets is pretty unlikely.

The first rule in these places is "Tell no-one anything", seriously you can lose your job for taking a camera inside some of these test areas let alone giving away clues.

but on the bright side often the data and test results are so derivative of a particular manufacturers work that it would be of little use except in copying a design rather than creating one from new.

I hope this helps at least in an understanding of how the industry works,

Best Regards
Rick

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Originally Posted by Rick Tiglon Eng

Hello,
I don't want to burst any bubbles, but having worked in Automotive OEM design facilities, the odds of getting anyone currently working for one of those names to come out here giving away secrets is pretty unlikely.

The first rule in these places is "Tell no-one anything", seriously you can lose your job for taking a camera inside some of these test areas let alone giving away clues.

but on the bright side often the data and test results are so derivative of a particular manufacturers work that it would be of little use except in copying a design rather than creating one from new.

I hope this helps at least in an understanding of how the industry works,

Best Regards
Rick

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Never hurts to try though does it? :D