I believe that is whats used to push the pistons down. 😆
If you are talking about managing the heat in the exhaust piston, yes thats an issue. In the boat engine above, the exhaust piston was cooled by fuel under the piston like a normal twostroke. I have since learnt other methods of exhaust piston thermal control, still using the crankcase as an air pump, like a normal twostroke.
Add a tuned pipe and you have the simplest uniflow engine with real power. Maybe with a version of your injection system it could meet emission rules. In any case, the catalytic muffler's back pressure isn't as harmful as in a four stroke.
Lohring Miller
PS I spent a Christmas day jet boating on the Haas River. I love New Zealand.
You published this for a long time and at the time it was of great interest to me, but from my point of view they were only theories that I had not seen demonstrated.
This year 2020, two prestigious researchers from this forum have carried out experiments with mechanisms in which the pressure of the crankcase makes them work.
1nd Mr. Señor Katinas, published in March, reeds in the transfer, I am very struck by the graph of the 4th configuration.
2nd Mr. Ken, published in April, reeds in the butt, it seems to me that the behavior of the engine in the video is similar to the graph of the 4th Katinas configuration
My English is not bad, it is only from the Google translator, because I do not know English, there are some of my errors.
As I have already said the two experiments clarify certain things about what is expressed by TZ250, in both cases the crankcase is full of clean mix, since the contamination cannot enter due to the physical barriers of the reeds.
They also demonstrate that the maximum crankcase pressure is at low rpm, which is when the reeds resistance overcome.
Whenever I have discussed this injection system, Ken Seeber has been referred to me for more information.
With this type of injection system some brands "aprilia, honda and ktm" have been investigated to apply it to engines over 50cc.
This new research work can help us understand why cylinder 250cc motorcycles have never been marketed with this type of system.
https://www.sciencedirect.com/scienc...16236120300399
Goodmorning everyone. I am converting my enduro bike (KTM exc 125 2006). i am doing all the necessary work and i already have all the necessary hardware (speeduino no2c, iat, CLT, wideband 4.9, tps, trottle body 38mm with iwp 043 330cc injector).
flywheel modified with 12-1 teeth
I wanted to understand with you who can help me for an initial tune to use
I need how many map sensors and where should I install them?
give me all the advice you can and if I'm doing something wrong
Hi MDJGyurgeiz. Great to see your project. The first thing to know is that there is a definite barrier about 9-10,000 RPM for fuel injecting two strokes. Above 10k RPM you will need staged injection. Below that you may get away with a single injector and at about 7-8k RPM a single injector is definitely possible.
This is because of limited time at higher RPM and the fact it takes an injector a finite amount of time to open and as its opening it dribbles fuel. An injector big enough to get the job done in the limited time available at high rpm dribbles far too much for successful tuning at lower RPM and Load. So two injectors are required, a small one and a much larger one. Two physical "B" port injectors can be treated as one logical injector when they are fired together.
KTM's EFI 300 with two physical injectors, one in each "B" port does a neat trick. At low RPM and Load they alternate the injections from side to side and when the RPM gets up or the Load increases they fire both together.
My 125 uses a 50cc/min small injector for low RPM and/or low Load and then switches over to the two big (160 cc/min each) B port injectors for a (logical) injection of 320cc/min.
MAP and MAF air flow sensors from a car will not work on a single cylinder two stroke. The reasons are all explained in earlier posts on this thread.
To get your bike up and running all you need is a TPS (throttle position sensor) and ambient air and cooling water temperature sensors. And maybe a MAP sensor connected to the outside air for variations in daily ambient air pressure.
The best MAPing method to start with, is the Alpha-N approach. This is just RPM vis TPS. Very easy to get started with and to tune for best power.
Alpha-N works well for anything pedestrian like a 300cc enduro bike or a two stoke car engine, basically anything two stroke that is not particularly high performance and maybe maxis out at less than 8,000 RPM.
A tuned 125 that relies on the pipe for its power needs a touch of VE volumetric efficiency in some feathering the throttle situations like approaching and exiting from a corners apex. The reasons for this is also explained in other posts on this thread.
But get your bike running with an Alpha-N map to start with, then add in a second VE map for fine tuning later.
A wide band O2 sensor is real handy for tuning for high power and areas on the map where the engine is running on the pipe and the engines trapping efficiency is at its best. But a O2 reading can be misleading when there is air short circuiting out the exhaust port or the engine is too rich and miss-firing. The O2 sensor will tell you air/fuel is lean when in fact its far too rich. Just another example of how four stroke thinking can be a trap with two strokes.
Good luck and please keep posting pictures and reports on your progress. Happy to answer questions here.
thank you very much for the advice, I will proceed as you advised me. do you think the map sensor at the moment is better to connect it to the throttle body?
can you recommend a petrol pump with integrated regulator to connect the outlet to the petrol tank?
can I ask your help to configure the tunerstudio tune?
No. do not connect it to anything, just let it sense the outside ambient air pressure.
I am using the Speeduino V4 board with the onboard MAP sensor. I have not connected a hose to the sensor, it just reads ambient air pressure. That way it can adjust the tune for elevation and air pressure changes in the day.
Get your project started with the Alpha-N methodology first, (TPS vis RPM) then we can add a pseudo MAP sensor later for an additional VE map.
This is the fuel pump I use https://www.ecotrons.com/wp-content/...-spec-V1.0.pdf you will be able to find something similar and cheaper on AliExpress. I use a Honda (but could be anything) 3,5 bar fuel rail pressure bypass type regulator salvaged from a car wreckers.
Yes, I may be able to help. What Speeduino board are you using? For technical Speeduino problems like noise on the signal line you may have to go to the Speeduino projects forum but anything two stroke EFI tuning with your project I may be able to help.
EFI and two strokes does work, people have had great success with it.
A big must. Get the paid for full version of Tunerstudeo and their Data logging and graphing software.
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Later, for a two stroke VE table we need to do something different to four strokes.
We need to create a pseudo MAP value that mimics four stroke behavior.
This search will bring up a lot of references about it on this thread.
First follow this link:- https://www.kiwibiker.co.nz/forums/showthread.php/185773-Speeduino-2T-EFI-Project?
Then copy and paste this in front of the https: Crankcase pressure site:
And you should see a Google page that looks like this:-
If you have Google and you can use the "site:" option then you can find things much more easily.
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