Speeduino 2T EFI Project

[TZ350]

I have now got the Speeduino and Ignitec talking to each other. I am using the Speeduino's number one ignition-out locked at 15 deg and the Ignitec base set at 15.

For things to work I had to tie the Speeduinos ignition output to earth with a 10K Ohm resistor that way the ignition pulses went to 0Volts between ignition events and the Ignitec could tell what was going on and when to fire.



Relevent Ignitec and Speeduino set pages.

[ceci]

Hi TZ350, sorry for filtering this here.
I want to know your opinion
https://www.facebook.com/groups/6710...2578262822338/

I believe it is a conduit for a pressure sensor and NTC.
Operation: when discovering the conduit the skirt of the piston (in each cycle) the pressures of both are equal, the sensor registers if there was variation.
Advantage: it registers the actual load of the crankcase in each cycle, in a more simplified way since it only records the maximum and not all the crankcase pressure.
Utilization: control of the powerjet for a correct use

[ceci]

I analyze what function this conduit can have and I can only find the reason that I already mentioned (transmitting the pressure of the crankcase to a MAP sensor)



I think having more data is not beneficial. You have to separate the valid from the rest (use of time to perform this task). It is not necessary to know all the pressure of the crankcase throughout the cycle
Using as a reference your data in which you quote that in idle the maximum pressure has the crankcase and that the piston being in TDC is the lowest for each cycle.
based on this concept the starting pressure value would be 1 and as the rpm motor goes up we would go to less

[TZ350]

I want to know your opinion
https://www.facebook.com/groups/6710...2578262822338/

Hi Ceci. I have seen that picture before on the Team ESE thread I think.

From memory it was an injector to overcome a problem with a particular rider who would crash down gears and rev the engine excessively in overrun causing seizures. The injector was to add a bit of fuel and extra oiling while the throttle was shut during overrun.

If you have the time you could search the pictures on this thread:- https://www.kiwibiker.co.nz/forums/s...tuner/page2066 ... a picture leads to the related post.

[ceci]

Hi Ceci. I have seen that picture before on the Team ESE thread I think.

From memory it was an injector to overcome a problem with a particular rider who would crash down gears and rev the engine excessively in overrun causing seizures. The injector was to add a bit of fuel and extra oiling while the throttle was shut during overrun.

If you have the time you could search the pictures on this thread:- https://www.kiwibiker.co.nz/forums/s...tuner/page2066 ... a picture leads to the related post.

At the moment I do not have my press collection of the motorcycles of past decades.
If I remember that in the report of the KTM 125 GP mentioned carburation problems in certain situations, what I do not remember is that they solved it with an injector.
A powerjet varies the mixing ratio independently of the air flow (the important thing is to know when and how it has to vary) and how do you know if you do not have data?



https://marcndm.skyrock.com/32793849...c-suite-2.html

These according to indeican in this page are the carburetors used, they are ELECTRONIC carburetors
The theory that I have is the most economical and simplest (no injection pump needed "is not injected only with an injector, you need a pump and many other things").
A direct injection to the crankcase to enrich the mixture I see it very complex for something that the powerjet makes you

[TZ350]

.
Here you are Ceci, I found the original post. You are right, it was instead of a power jet. Maybe my memory of an injector being used to eliminate seizures from overrun was an Aprilia GP thing.
.

Not likely; the 125 cc KTM GP-bike already had an injector in the crankcase that injected through a port below the exhaust port.
They used it instead of a powerjet and it would only have been logical to use the same setup for full EFI.
Attachment 328804 Attachment 328805 Attachment 328806

[TZ350]

.
Got the Beast running today, just.

The MAP value varies depending on the difference between the High and Low pressures in the 2S crankcase. Close the throttle and the difference is less and the MAP value is lower. Open the throttle and the difference increases and the MAP value goes up. Just like it does with a 4T.

Hit a bit of a snag, at low speeds, not much more than idle (1000 to 3000 rpm) that I have been able to run I have found that the difference in pressure is much greater with the throttle closed than it is when the throttle is partially open.

Makes sense though, a closed throttle allows the descending piston to give the trapped mixture a good squeeze but any pressure applied to the mixture when the throttle is open just allows it to escape out the inlet and so the pressure difference is less.

[TZ350]

I find this description on Ecotron site

2-Stroke Small Engine Fuel Injection kit is designed to run 2-stroke small engines. This kit can drive 2 injectors per cylinder (one big injector, one small injector). During idle, and low part loads, ECU only opens the small injector for small fuel quantities; it will switch to the big injector for mid, or mid-high loads; and it will activate both injectors at WOT conditions. The transitions between the injectors are transparent to the driver and they are so smooth that the driver can not feel it. This setup controls the accurate AFR (lambda) from idle all the way up to 16000RPM. We have a

The whole idea of 2 injectors (one small, one big) is based on the need: 2-stroke engines have only half the time to inject fuel compared to 4-stroke (360 vs 720 degrees), and the 2-strokes usually (esp. high-end engines) have such a wide range of RPM (2000 - 16000rpm, for example). One injector is not able to cover the whole RPM range, simply because every injector has its physical limit: the fixed flow rate. If you use a big injector to cover the high end, then you will have too-rich idle. If you use a small injector, to have a good idle, then you don't have enough fuel for WOT. Given a certain inject flow rate, you can only run an engine either at low RPM range or high RPM range, but not both (from 2000 to 16000rpm).
For example, an engine runs at 16000rpm, you only have max 3.75ms time-window to inject fuel. In this short time, you have to inject enough fuel for WOT conditions. If you pick a super big injector, you will not be able to run idle (too rich even at 1ms pulse width). So what can you do? add more injectors. At low load, use one injector, and at high load/high RPM, use 2 or more injectors. That's why you see a lot of racing engines have 2,3, or even 4 injectors per cylinder. Our system is better: while others use the same size of injectors, we use one small, one big injector. Why? because at idle, you need a very small size of inject, and at WOT, you need a big size. The benefits: you can run the engine at ideal AFR over the whole wide range of RPM, with only 2 injectors (again, save cost compared to 3 or 4 injectors). The tansitions from idle, to WOT, will be: the small injector works at idle, low load; then it switches to the big injector at mid-high load (the small one shuts off); then at WOT both injector works together. And all these are made transparent to users!
This is our unique technology for 2-strokes, not even big companies have this.

I want to implement same or similar in my EFI. Is this specs rational enough or someone advice corrections?

Yes totally on the money but only half the story.

Ecotrons use the Alpha-N topology for their 2S fueling map and it works well on 2S's that are not very pipe dependent like 250cc Enduro bikes but Alpha-N does not support high performance 2S's like GP125's where they make a lot of power through clever use of their pipe.

Because Alpha-N is a fixed pre determined fuel squirt amount for every TPS vis RPM cell on the MAP. This only works half the time for a high performance GP engine because AN cant be both correct for when the engine is on the pipe and when it is not.

I use the 10/10 concept. Anything less than 10,000 RPM and 10 bar BMEP is probably possible with an Ecotrons but anything making more than 10 bar BMEP and 10,000 RPM needs something more sophisticated for their fuel mapping.

My current EFI 2S efforts are aimed at solving this and am looking for ways to see the actual changes in airflow through the crankcase. Currently I am looking at the difference between maximum and minimum crankcase pressure and how it changes when the engine gets on or comes off the pipe.

[patouille]

Hello,
I just registered in this forum as I saw this very interesting topic. I'm glad to see someone is trying and sharing his ideas.
I built my own 2S EFI for my racing Solex (a very particular 50cc here in France).
The beginning is very encouraging, take a look : https://www.youtube.com/watch?v=LW19l64nm7Y.

I wanted to share some of my feedback which is sometimes different form the TZ350 observations.
I made my own printed circuit board (still based on the arduino mega chip). The code is from 4S codes I found in the internet and adapted to my use.
The main purpose was to make it run at idle but it worked beyond my expectations. As you said staged injection is more appropriate, I was planning to use it but it turned out that my Suzuki 600GSR injector could achieve the best idle stability (~1100 µs PW at 2200 RPM) I ever had with any carburetor (which is of course way bigger than necessary) !
The second thing different from your observation is injector timing (but keep in mind it's a throttle body injected engine). The injector is triggered by just the magnet of the ignition rotor in front of a hall sensor. I added a triggering offset tuning possibility but with no noticeable effect.
My algorith is working in alpha-N because I could never have a significant MAP reading (I tried before the throttle plate, after and in the crankcase). Your idea of the sensor reading triggered by a specific crankshaft position is clever. I will probably try that.
Despite the bike achieving all of its regular RPM range in the video (~14000RPM), it was with the bike on its stand. On the road I'm currently having some trouble over 10000RPM. I tried different mappings with no effect. I'm still working on it...
For more info, you can see our facebook page (sorry in french).

[ceci]

.
Here you are Ceci, I found the original post. You are right, it was instead of a power jet. Maybe my memory of an injector being used to eliminate seizures from overrun was an Aprilia GP thing.
.

Thank you very much TZ350 for the information.
KTM takes pole position in 2S injection research.
Three models: crankcase, cylinder and transfer port.

[speedpro]

KTM takes pole position in 2S injection research.

KTM would like you to think so

[TZ350]

KTM takes pole position in 2S injection research. Three models: crankcase, cylinder and transfer port.

This has all been done successfully here in New Zealand well before KTM. Possibly even the inspiration for KTM with regards to how to get their overly complicated first attempts right. They certainly knew about these bikes before they abandoned what was not working for them and changed to B port injection themselves too.

Some Youtube clips of transfer port and crankcase injected 2T's None of this is my work. The Kawasaki and Yamaha were running well before KTM's EFI 2T offering.

EFI Kawasaki Bighorn on the dyno https://youtu.be/ifSEql1X4R0
EFI Kawasaki Bighorn Trail ride 1 https://youtu.be/eleqBGvOM4M
EFI Kawasaki Bighorn Trail Ride 2 https://youtu.be/CnIemdISKrM
EFI Kawasaki Bighorn VMX https://youtu.be/v8i6ps0PdVI

Maramarua classic forest trail ride https://youtu.be/ZqzOgOJuJ1E

http://youtu.be/eleqBGvOM4M
http://youtu.be/hOGZ5llowoU
http://youtu.be/1YG9ko8-Nwk
http://youtu.be/UEQli7nuak4

GerbilGronk is worth a Youtube search.

"B" port injected Yamaha YZ250


Crankcase injected Kawasaki Bighorn

[TZ350]

.
Just in case KTM try to also claim they "invented" a sleeve valve two stroke. Well you have seen pictures of a running one here well before KTM have even started talking about it.

The most powerful piston powered WW2 aero engine was the sleeve valve two stroke "Rolls-Royce Creasy".

A 2S sleeve valve motorcycle engine with port fuel injection might be something .......... remember you heard it here first...... looking at you, KTM.

[ceci]

First cylinder: Orbital Di-tech (Aprilia leonardo SR500 and did that motorcycle work?).
Second cylinder: Bimota VDue and Sherco (Bimota has the patent for that method).



https://patentimages.storage.googlea...93022545A1.pdf
https://patentimages.storage.googlea...P0591509B1.pdf

If true the third is a copy of Flettner.
These three and the GP125 to the crankcase.
From my scarce knowledge they place it in the manufacturer that more to investigated

[ceci]

Beta also tried to inject by that method 2