ESE's works engine tuner

[skako]

That looks very good! Did you base it on Prof Blair's first or second two-stroke book?

Vannik
The simulator is based on the first book by Prof. Blair.
I've been reading some of your work.
You have made a very good EngMod2t.
I would love to have it and compare the results from my simulator side by side, to see where I got.
My simulator is relatively simple, student-grade, but it performs gas-dynamic calculations in the way set by prof. Blair.
I will post some characteristic graphs that can show it better.
Now I know what simulator means.
Even more, how to get closer to the goal with the help of the simulator.
Vannik, you have great respect from me!

Welcome Skako. I must say your 'poor English' is definitely better than what Google Translator can do, and I am looking forward to more contributions from you.
Putting together a simulator will have forced you to fully understand every physical, mathematical and logical step in the process, and that alone will have given you a level of insight not many of us will achieve. My respect!

Frits,
I read a lot of your expert comments on this forum and also on another forum.
I know how to evaluate what is good and what I need.
I am aware how much I know.
I am aware even more how much I don't know.
I have many of your comments translated into my language and stored in one file.
Frits, you have great respect from me!


trevor amos
I will put a few more thumbnails of the gearbox

'-------------------

Here are some of the graphs.
It is not always possible to obtain a good characteristic of the graph.
This means that I have to change parameters on that simulation model.
I fix it until I get closer to my goal.
These are all simulation models that have not been verified and that I should check on a Dyno-desk, which I unfortunately do not have.
I hope that will happen one day.

[TZ350]

It would be interesting to find the upper limit on rv case volume before you start going backwards. With no familiarity with that engine, where did the rod/stroke ratio end up?

I am not sure what a practical rotary valve upper case volume would be. The limit might just be getting enough mixture up into the cylinder to get the fire started. With the pipe doing the rest.

Rod ratio. 48mm stroke 115mm between centers rod. 115/48=2.4 so rod ratio is 2.4:1. I would have used a longer rod if I could get one.

[husaberg]

I am not sure what a practical rotary valve upper case volume would be. The limit might just be getting enough mixture up into the cylinder to get the fire started. With the pipe doing the rest.

Rod ratio. 48mm stroke 115mm between centers rod. 115/48=2.4 so rod ratio is 2.4:1. I would have used a longer rod if I could get one.

i assume you used a rd rod? If so ktm200 is 3mm longer at 118mm with 22mm and 16mm pins

[philou]

Hi,
For the last few years, with longer or shorter interruptions, I have been trying to make a Two-stroke simulator.

Hello,

congratulations on your program.

there is a very old wave simulator that works in MS-DOS.
here it is if it can help you compare your results

http://adardaine.free.fr/file/004Twostroke_F.zip

[skako]

Hello,
congratulations on your program.
there is a very old wave simulator that works in MS-DOS.
here it is if it can help you compare your results

philou
thank you very much, I am looking forward to this gift.
I currently translating text files into the Croatian language and I embellishing the technical terms a little more for better understanding. I think it could be interesting.
When I get some comparable results I will present them here.

[Peter1962]

I am not sure what a practical rotary valve upper case volume would be. The limit might just be getting enough mixture up into the cylinder to get the fire started. With the pipe doing the rest.

Rod ratio. 48mm stroke 115mm between centers rod. 115/48=2.4 so rod ratio is 2.4:1. I would have used a longer rod if I could get one.

Jan Thiel & Frits wrote some very interesting experiences concerning that specific question on Pitlane-biz. ( which is worldwide the second best 2 stroke forum, after the Bucket subforum on Kiwibiker which rules )

Testing different setups gave the answer : 120 mm rods were best. (when combined with a rotary valve ! )
Reed valves are a different animal.

[philou]

Pitlane-biz. ( which is worldwide the second best 2 stroke forum).

French forum speaks a lot and does not do much

rsw connecting rod of 115 mm and measured 118 mm on an rsa

[TZ350]

.

Telflon works okay with Methanol i sent rob some combability stuff
https://www.methanol.org/wp-content/...ol-Service.pdf.

Thanks Husa for the tip about Teflon seals. I checked the chart and Teflon got an "A" and "D" rating, not sure why.
But it might explain why some have had luck with Teflon seals and Methanol and the Yamaha Teflon tipped ones did not like it.



The original Kawasaki seal and a Viton one I tested did not like the 50% Methanol 45% 98 5% Acetone mix when soaked for as little as an hour.
They both returned to their proper shape when they were left to dry out overnight.



I could not get a Teflon seal or an EPDM one which is also rated "A" for Methanol but I did manage to test a Nitrile one.
Soaked it for 24 hours and it showed no signs of swelling. The good thing is that Nitrile is cheep and the most common.

[philou]

maximum linear speed for the seal lip in nbr : 14 m/s

[TZ350]

.
Ready to start sorting the jetting now that it has given up drinking its gearbox oil.

Ear protection and a respirator for the methanol fumes plus an exhaust fan.

[F5 Dave]

I never finished the extraction fan project, but now the dyno is gone, the inline fan is as I type , pumping hot air out the bedroom window so we can sleep tonight.

Interested in results Rob.

[husaberg]

.




Thanks Husa for the tip about Teflon seals. I checked the chart and Teflon got an "A" and "D" rating, not sure why.
But it might explain why some have had luck with Teflon seals and Methanol and the Yamaha Teflon tipped ones did not like it.

Odd i only seen this bit.


From what i understand with the telflon seals i think only the inner ring that contacts the shaft lip part of the seal is made of or maybe even coated with Teflon
the rest will be some other form of "rubber"
That might explain the variable results?

[skako]

That looks very good! Did you base it on Prof Blair's first or second two-stroke book?

Vannik
I am looking at the results given by philou in the link above for Cappra_250.
Now I see an error in my result. My fluid mass flows are not equal.
DRmass = SRmass = Exmass
I have deviations there. I have to study the book again. I must see the program code and that all learn and fix.
It will take more time, but I will be persistent and will not give up. I assume that the error is somewhere in the code Inletflow, Outletflow, Boxstate.
What do you think about how much these deviations flow-mass could be allowed and acceptable?

[Vannik]

Vannik
I am looking at the results given by philou in the link above for Cappra_250.
Now I see an error in my result. My fluid mass flows are not equal.
DRmass = SRmass = Exmass
I have deviations there. I have to study the book again. I must see the program code and that all learn and fix.
It will take more time, but I will be persistent and will not give up. I assume that the error is somewhere in the code Inletflow, Outletflow, Boxstate.
What do you think about how much these deviations flow-mass could be allowed and acceptable?

Skako, the problem you have is that the first book uses the homentropic method of characteristics (MoC) to calculate gasdynamics. The problem is that the MoC is a first order method and it is not conservative so it does not preserve mass or energy. It can gain or loose mass and energy. To preserve mass and energy requires a conservative method, usually a two-step finite difference method like Lax-Wendroff or Harten-Lax-Van Leer with some sort of correction, or the GPB method that Prof Blair developed and use in his second book.

Even so the MoC has been used for many years with great success but more to study trends and not more absolute values.

I do not know your background so do not know if my answer above helps you. Hopefully I have not offended you.

[wobbly]

I used Dynamation for years , but in the end its code writer whom I had become good friends with ( Curt the boss at HotRods ) decided that the MoC was a fundamentally flawed
methodology and it wasnt worth the effort to create work arounds or rewrite the programming.