ESE's works engine tuner

[TZ350]

For me adopting of cars EFI to small 2-strokes sometimes looks like fitting saddle on a cow

When Regina Mayer couldn't have a horse, the 15-year-old saddle trained a cow called Luna. https://caveviews.blogs.com/cave_new...-cow-luna.html



A very clever cowgirl ...... ..... if you have a passion, you do what you have to do.

[wobbly]

TeeZee , the comment about ignoring the absolute value , just measure the delta between high and low values is a valid one.
This was the beakthru used in Dr Longdills thesis I supervised at AK Uni where he used two fibre optic detectors in the combustion
chamber to measure two differing wavelengths of flame colour.
The difference in the two intesities was not affected by the absolute values , and this was used to measure the burning flames A/F ratio and correct
the output of the injection ECU.
It fixed the issue of " sooting " on the detector surfaces changing the values of light intensity measurements.
The system worked perfectly , but ultimately needed another input to correct the erroneous colour information that occured during detonation events.

[Grumph]

Stihl and Husqvarna smootly meter correct ammount or fuel in crankcase neglecting high rpm. Their ugly crankshafts smashed fuel drops better than nozzles.

I had as well small 3w UAV engine with EF* It have simple fuel pump with 2 microscopic gears. ECU regulate pump rpm. Worked perfectly.

Both solutions dont required high presure pumps, pressure regulators, numerous tubes and sensors.

That sounds a lot like Hilborn injection with the pump speed/output electronically regulated. I'm assuming from your description it's constant flow ?

[TZ350]

TeeZee , the comment about ignoring the absolute value , just measure the delta between high and low values is a valid one.

Yes, it is my intention to only measure the delta between high and low, then multiply it by a simple correction factor to increase its magnitude to something similar to what a regular four stroke MAP value would be.

That way I can use regular common after market four stroke type EFI CPU units and mapping. It has taken a bit of work to figure out how to do this, not quite there yet but I feel I am closing in on it.

[TZ350]

On my GP/NSR110 3 times Delta crankcase pressure roughly equals the MAP reading you would expect to see from a four stroke's inlet manifold.



This is an actual scope reading at about 11,500 rpm of a MAP sensor reading the crankcase pressure of my GP/NSR110. The yellow spikes are the ignition trigger pulses.

The purple steps are the sensors output each milli second. The sensor outputs its last (averaged??) reading every milli second for a milli second, hence the steps.

It is easy to see that the low pressure is around TDC and the high pressure at BDC as seen by this pressure sensor. I think processing delay shifts the timing from reality a bit. But that is not a problem as it is consistent.

My mission is to capture the readings with my Arduino Nano, process them and then pass a pseudo MAP reading to the EFI's CPU.

The Arduino Nano can easily take the two readings required every cycle, in fact it takes three high and three low and picks the best. Then averages them over ten readings, finds the delta and multiplies it by 3 and finally outputs it as an analog pseudo MAP reading. I have successfully simulated the fluctuating crankcase pressure and tested the pseudo MAP software on the scope to 15,000 rpm.

Technically simple to do but it is just taking me a bit of time to achieve it in reality on my bike.

I think KTM have got it sorted and are doing something similar on their latest EFI 2S bikes.

A small tube in the back of the cylinder is connected with an intake pressure sensor, which supplies pressure data to the control unit. .... https://www.ktm.com/en/enduro/150-ex...engine-exhaust

[Flettner]

I think so, you might find KTM are spying here. KTM were certainly awear of my work documented on TSM.

[TZ350]

Kenny Roberts and the Indy Mile (2009) riding the TZ750 powered Flat Tracker.

[peewee]

I think so, you might find KTM are spying here. KTM were certainly awear of my work documented on TSM.

if theyre spying then what name could they be using? or they dont sign up at all. some time ago i told the big chief around here to atleast make the photos invisible to anonomous guests or somebody could spy easily with no name

[obelsik]

Long time lurker on this most excellent place (No I dont work for KTM, I live in Auckland and drive a YZ250 ;-)).

The GET replacement EFI box for the the KTM TPI models also includes a "race" option where the injectors are moved to a new manifold mounted between throttle body and reeds.
This video suggets this improves low end power which is crucial for hard enduro:
https://www.youtube.com/watch?v=_cNscr4E3GU


Then we have this, which is also suggesting dual mounted injectors mounted at the throttle body:
https://www.youtube.com/watch?v=DMLqtKqHt9U
Two Stroke Performance does mention that it does miss with big throttle openings and low loads which makes it unsuitable for motocross where you need to blip the trottle in the air.

[F5 Dave]

I also don't work for KTM but if they were to send me a regular significant enticement I would gladly sell out all the ideas I come across here.

[Note to Forum members: Dont worry- of course I wouldn't]

[Note to KTM: Yes I will].

[TZ350]

The GET replacement EFI box for the the KTM TPI models also includes a "race" option where the injectors are moved to a new manifold mounted between throttle body and reeds. ... https://www.youtube.com/watch?v=_cNscr4E3GU

Then we have this, which is also suggesting dual mounted injectors mounted at the throttle body: ... https://www.youtube.com/watch?v=DMLqtKqHt9U

Yep, it looks like there is already an aftermarket re programmable ECU with new maps that can be changed for the EFI KTM's. Maybe a good thing. Looks like high performance 2S EFI is going to be a real thing.

[oldjohnno]

Stihl and Husqvarna smootly meter correct ammount or fuel in crankcase neglecting high rpm. Their ugly crankshafts smashed fuel drops better than nozzles...

That's interesting - some time ago I was thinking about injecting fuel (methanol) up against the underside of the piston crown as a way of improving piston cooling. But I wasn't convinced the fuel would be sufficiently atomized and wondered whether the loss of cooling in the intake tract would cost power. I'm still tempted to give it a run on the dyno.

[lohring]

Yep, it looks like there is already an aftermarket re programmable ECU with new maps that can be changed for the EFI KTM's. Maybe a good thing. Looks like high performance 2S EFI is going to be a real thing.

$900 seems a little steep and is out of my price range.

Lohring Miller

[TZ350]

$900 seems a little steep and is out of my price range. Lohring Miller

Yes, agreed. It is why I hope to post a proven working example that makes it easy/cheaper to do for ourselves.

I don't think KTM are using anything too fancy themselves and I wanted to stick with what was affordable for DIY.

Automotive sensors can be picked up cheap on the Net.

The Speeduino EFI CPU's firmware code is free and open source so you can modify it to suit your needs.... https://speeduino.com/wiki/index.php..._-_Easy_Method

TunerStudio for adjusting the Speeduino's mapping, the basic version is free.... http://www.tunerstudio.com/index.php/tuner-studio

The Speeduino Shield DIY naked board for the Arduino Mega is cheap and they can also be brought fully made up.... https://speeduino.com/forum/app.php/page/buy

The Arduino Mega itself is relativly inexpensive.... https://www.amazon.com/ARDUINO-MEGA-.../dp/B0046AMGW0

The Arduino Nano is cheap .... https://www.amazon.com/OSOYOO-Arduin.../dp/B00UACD13Q

So Inexpensive, Cheap or Free. As a DIY project I hope others might try 2S EFI too. And for the sake of my pocket I am keen to keep this affordable.

[TZ350]

Air Cooled and Fuel Injected Suzuki GP125

A series of EFI dyno runs taken at different throttle positions on my old air cooled 125. I had spent a lot of time mapping the Alpha-N fuel injection table. Alpha-N only looks at TPS and RPM and for each cell on the table you map an engine "Load" value that is used by the CPU to determine how much fuel to inject at that particular point, every time, nothing changes. This worked well for anything above 45% throttle position but it is not a flexible fueling system. More suited to drag racing than road racing.

I got the Alpha-N mapping fairly good and even rode the bike like that a few times and towards the end, sort of successfully but throttle control coming out of corners was not so sweet.

The current plan is to use Alpha-N above 45% TP and VE, volumetric efficiency below 45%. VE looks at engine volumetric efficiency vis manifold absolute pressure (MAP). That way fueling can be variable in response to the airflow changes induced by the pipe.

This way I can have the best of both worlds. Alpha-N which has proved reliable and very tune-able when the motor is on song and responsive variable fueling at lower throttle openings.

Combining the two mapping typologies, Alpha-N and VE should be relativly easy with the Arduino Nano pseudo MAP system. Below 45% I make the output variable and above I make it fixed at atmospheric.