Ecotrons Engine Management [Archive] - Page 2

TZ350

26th December 2017, 09:15

.
If a tuned two stroke engine does not fire, less air is drawn through the motor by the wave action of the pipe.

This change in wave action is more noticeable on small capacity high performance engines and significant on small throttle openings < 25%

The project is to develop a Arduino routine for switching between Alpha-N maps on a fuel injected 2T engine.
By determining from residual cylinder pressure if the EFI 2T engine has fired or not and switches to an alternative map if the engine did not fire on the last cycle and needs a leaner map.

334206

My Aduino Nano project for switching maps between the Alpha-N map and the driver demand Lambda map on the Ecotrons EFI system.

334207

A pressure sensor is used to measure the residual cylinder pressure just before exhaust port opening.

334205

I am using a signal generator and oscilloscope to mimic the ignition and cylinder pressure cycles so I can develop the project on my bench top.

The plan is based on determining if there is a cylinder pressure pulse between two ignition pickup pulses.

But of course there would be no pressure pulse if there was no ignition pickup pulse so we only need to look at the cylinder pressure pulse followed by an ignition pickup pulse.

334204

The green shows how there is higher air flow through the motor on the following cycle if there has been combustion and a proper cylinder pressure pulse due to the wave action of the pipe but if there is no combustion then the air flow is much reduced during the following cycle.

Below is my code, it looks to work on the test bench Ok. When the new pressure sensors arrive I will get to test the Arduino relay switch idea on the bike properly.

// Arduino Nano map switch routine.
// Routine for Switching between Alpha-N maps on a 2T engine.
// By determining from residual cylinder pressure if the EFI 2T engine has fired or not.
// Switches to an alternative map if the engine did not fire on the last cycle.
// Because if the engine does not fire, less air is drawn through the motor by the wave action of the pipe.
// This change in wave action is more noticeable on small high performance engines and throttle openings notable < 25%

const int Relay = 8; // the number of the relay pin
const byte EngIgn = 2; // the number of the ignition pulser interupt pin
boolean EngIgnState = false; // Boolan EngIgnState
boolean CylPressureState = false; // Boolan CylPressureState
int CylPressure = (17); // the number of the analog cylinder pressure sensor pin

void setup()
{
pinMode(LED_BUILTIN, OUTPUT); // initialize digital pin LED_BUILTIN as an output.
pinMode(8, OUTPUT); // initialize digital pin D8 as an output.
pinMode(2, INPUT); // initialize digital interupt pin D2 as an input.
pinMode(17,INPUT); // initialize analog pin A3 as an input.
analogReference(DEFAULT);
attachInterrupt(digitalPinToInterrupt(2), IgnitionPulse, RISING); // ignition pickup pulse.
digitalWrite(8, HIGH); // start with the relay off
digitalWrite(LED_BUILTIN, LOW); // start with the LED off
}

void IgnitionPulse () {EngIgnState = true;} // on this revolution we have seen a pulse from the ignition pickup.

void loop()
{do // now to see if the cylinder fired last time and the pipe sucked extra air through the motor.
// if the pipe did not suck extra air then we need to switch to a leaner map.

{CylPressure = analogRead(17);

if (CylPressure >= 250) // looking for cylinder pressure.
{CylPressureState = true;}
else
{CylPressureState = false;}

if (CylPressureState == true) // is there cylinder pressure after an ignition event?
{digitalWrite(8, HIGH); // turn the relay off
digitalWrite(LED_BUILTIN, LOW); // turn the LED off
CylPressureState = false;}
else
{digitalWrite(8, LOW); // turn the relay on
digitalWrite(LED_BUILTIN, HIGH);} // turn the LED on

EngIgnState = false;
}while(EngIgnState != true);
}

Ulstermanone

17th May 2018, 02:32

I bought a small engine EFI kit and they assured me it was for a two stroke machine
It Has 38mm TB and not CDI
()
I have two versions of a trigger wheel
12/2 and 12/1
()
I have checked the ignition position and at zero all is good and I even got this motor to start and idle
(0
Problem is that it seems to be stuck in a four stroke cycle no matter what I do as even the end of injection angle has to be 360+200 so 540 to 560 which is the 2nd rotation of a four stroke cycle
I have confirmed pulses with a scope and no matter what I do the ignition is only firing every 2 rotation

TZ350

18th May 2018, 14:47

I bought a small engine EFI kit and they assured me it was for a two stroke machine

The problem is that it seems to be stuck in a four stroke cycle no matter what I do.

In the advanced calibration options there is a field that allows you to select 1 or 4 cycle.

There are two versions of Ecotrons software. ProCal and the latest EcoCal.

In EcoCal go to "EFI Basic Settings" at the bottom of the page.

Select "Variables" at the top of the page and then "Add Calibrations".

You are looking for "Val_nRevPerCycle" which is the one that allows you to select 1 or 4 cycle.

Have a look at the screen shots below to get an idea of the changes possible.

TZ350

18th May 2018, 15:25

336823

My current EFI efforts have been to use an Arduino Nano to read the analogue signal from a MAP sensor in the crankcase and find the Difference between the Highest and Lowest reading and output the difference as an analogue pseudo MAP signal to the EFI (electronic fuel injection)'s CPU (central processing unit).

The Arduino talks about “analogue” output on their card but they are fibbing a little bit because it is really PWM, pulse width modulation and not analogue at all. So not at all useful at all for use as a true analogue output but PWM is pretty good for controlling electric motors, LED’s etc.

336821

Arduino PWM (Analog) Tutorial:- https://www.arduino.cc/en/Tutorial/PWM

336822 336824

To get true analogue output with the Arduino Nano you need a DAC, digital to analogue converter like the AdaFruit MCP4725 and AdaFruits software library addon.

336826

AdaFruit MCP4725:- https://www.adafruit.com/product/935

AdaFruit Tutorial:- https://cdn-learn.adafruit.com/downloads/pdf/mcp4725-12-bit-dac-tutorial.pdf

336825

AdaFruit Library:- https://learn.adafruit.com/mcp4725-12-bit-dac-tutorial/using-with-arduino

Drew

18th May 2018, 18:36

What allowance for the information you wish to send, is your ECU equipped with?

The easiest way I can imagine is an ECU that has allowance for boost.

TZ350

18th May 2018, 23:09

The easiest way I can imagine is an ECU that has allowance for boost.

Hi Drew, Yes "Boost" its a good way of looking at it. Thanks for the idea.

what are you trying to achieve? It looks like you're trying to read an analog signal by outputting an analog signal.

336831

I am trying to read in an Analog signal from the MAP sensor, process it and then pass it out as an Analog signal to the EFI's CPU.

The Ecotrons EFI system expects a MAP signal from the inlet manifold. This is Ok for a 4T but does not work well on a 2T. Which limits a 2T to only using an Alpha-N map which I have found is problematic at low throttle settings below 25% with my 110cc tuned 2T engine.

Alpha-N maps are RPM/Throttle position = Fuel required. Simple and work well with predictable air flow.

My idea is to find the the difference between maximum and minimum crankcase pressure each cycle and output this in a modified form to the EFI CPU as an indication of real airflow through the two stroke's motor.

If I can find a good way to indicate changes in air flow (charging efficiency) then I may be able to also use a Volumetric efficiency map below 25%, just like 4T's do.

When the engine is on the pipe, Alpha-N works well but when the motor is swapping between on the pipe and off Alpha-N is either correct or to rich. So we need a way to adjust the fueling to match the changeable air flow.

Volumetric maps are RPM/Volumetric efficiency of the motor depending on manifold pressure as measured by a MAP sensor = fueling required.

As Volumetric efficiency (a 4T concept) is directly related to "Charging plus Trapping" efficiency (a 2T concept) then knowing the air flow should be a great help.

The plan is to use a Volumetric efficiency map below 25% throttle position and Alpha-N above 25% similar to a 4T approach.

336832

In my test setup the MAP sensor is the Analog input. The Arduino processes this Analog input and sends a 10bit value to the MCP4725 card. The meter is measuring the Analog output produced by the MCP4725 add on card.

The on/off/on toggle switch simulates the ignition trigger pulse for timing the start/end of each cycle. The trigger is connected to an interrupt pin. The MCP4725 feeds directly to the meter and it is also read by the Arduino on another Analog input pin so all inputs, outputs and internal processing variables can be serial line printed in real time to the PC's screen for de bugging purposes.

Of course, at the moment it is just a concept and I have no idea if this is going to improve my 2T's EFI system or not until I try it.

Ulstermanone

25th May 2018, 01:01

I did that Value many times and its well worded as in number of rotations for a complete cycle
Only thing it does is turn on the VE map on
When I put a scope onto the trigger and coil not once have I got it firing every rotation
I been back and forward with there tech guys and am exhausted
()
Thankyou for the reply and getting to the stage of giving up on this project all together
I just need the motor to fire every time and inject eveytime and they gave me an induction coil setup they say is good to 11.000 RPM and I have know idea how
()
Can I as another Question
Why is the ignition map they sent me for base setting starting at 33 advance at 2000rpm and 10deg advance at 12000rpm and not the other way around ?

In the advanced calibration options there is a field that allows you to select 1 or 4 cycle.

There are two versions of Ecotrons software. ProCal and the latest EcoCal.

In EcoCal go to "EFI Basic Settings" at the bottom of the page.

Select "Variables" at the top of the page and then "Add Calibrations".

You are looking for "Val_nRevPerCycle" which is the one that allows you to select 1 or 4 cycle.

Have a look at the screen shots below to get an idea of the changes possible.

TZ350

25th May 2018, 14:54

I did that Value many times and its well worded as in number of rotations for a complete cycle. Only thing it does is turn on the VE map on

That is interesting, does 1 cycle (2 stroke) = VE map turned off .... and 2 cycle (4 stroke) = VE map turned on.

When I put a scope onto the trigger and coil not once have I got it firing every rotation.

I would look at the trigger coil signal with a scope just to make sure the signal is consistent.

My own 2T EFI bike project uses a single tooth 20 deg BTDC and fires every 360 deg.

... another Question, why is the ignition map they sent me for base setting starting at 33 advance at 2000rpm and 10deg advance at 12000rpm and not the other way around ?

Four strokes start at say 10 deg and advance to 35 because of the time it takes them to burn all the air fuel mixture at higher RPM.

Two strokes start at say 30 deg and retard to say 10 at higher RPM because the turbulent action from air/fuel mixture being ejected from the squish area greatly speeds up the rate of mixture burn.

There are other reasons too, like transferring some of the heat from a late burn to the pipe to extend the over rev past peak power.

The four stroke has less advance at low RPM because the VE is very much higher at low RPM, way more than a two stroke, but the VE of a two stroke greatly improves as the RPM increases.

Ulstermanone

26th May 2018, 02:27

Thanks for the reply
Are you using a VRS pickup or Halls effect ?
()
From what I see of this software the VE table only effective in 4 stroke mode
()
Map sensor isn't needed and really no idea why they wanted an O2 sensor
Most modern 4 strokes do not use Map to find faze anyway
()
I used a 12 position missing 2 and then also have a 12 position missing one
I found the 12/2 works the best and tell the system only missing one
Allows the timers that extra distance to reset but not enough for fault as that is set to 3 in the Cal files
()
I scoped the trigger pulse and every time very good to be honest and shows up well and also the coil pulse relative to it
()
I made up a few good diagrams to help me try and understand the first value as in the offset to TDC pin and after that the last problem was the End of injection angle that really can be interpreted at least 2 if not 4 different figures

That is interesting, does 1 cycle (2 stroke) = VE map turned off .... and 2 cycle (4 stroke) = VE map turned on.

I would look at the trigger coil signal with a scope just to make sure the signal is consistent.

My own 2T EFI bike project uses a single tooth 20 deg BTDC and fires every 360 deg.

Four strokes start at say 10 deg and advance to 35 because of the time it takes them to burn all the air fuel mixture at higher RPM.

Two strokes start at say 30 deg and retard to say 10 at higher RPM because the turbulent action from air/fuel mixture being ejected from the squish area greatly speeds up the rate of mixture burn.

There are other reasons too, like transferring some of the heat from a late burn to the pipe to extend the over rev past peak power.

The four stroke has less advance at low RPM because the VE is very much higher at low RPM, way more than a two stroke, but the VE of a two stroke greatly improves as the RPM increases.

TZ350

26th May 2018, 21:29

Are you using a VRS pickup or Halls effect ?

336999

VRS pickup with only one lobe on the flywheel.

I don't use the Ecotrons ignition only the EFI side for fuel injection.

From what I see of this software the VE table only effective in 4 stroke mode

I am interested because Ecotrons changed my two stroke software so I could use VE and Alpha-N table. I have not tried it yet so not sure if I will actually still have 2T software or they have just activated it as 4T.

Map sensor isn't needed and really no idea why they wanted an O2 sensor
Most modern 4 strokes do not use Map to find faze anyway.

I use a wide band O2 sensor a lot on my 2T for tuning.

337000

The brown line between the two white coursers shows the small injector going lean before the larger secondary injectors take over. Probably needs a bit of injection angle end adjustment.

A MAP measuring atmospheric pressure is pretty handy on a 2T for automatic RAD changes.

I used a 12 position missing 2 and then also have a 12 position missing one. I found the 12/2 works the best and tell the system only missing one.

I am afraid I can't help much here as I only have experience with a single tooth wheel.

337005

I made up a few good diagrams to help me try and understand the first value as in the offset to TDC pin and after that the last problem was the End of injection angle that really can be interpreted at least 2 if not 4 different figures

Yes, I too had to make diagrams to understand what was going on.

I think the "end of injection angle" is supposed to be degrees before TDC but I suspect it may be degrees before the actual ignition sensors trigger point.

Anyway "end of injection angle" is when the injection ends, it starts earlier and earlier (degrees wise) as fuel demand and/or rpm increases.

I found the best position was 180 or BDC where the pipe is supposed to be sucking the hardest. Others swear by ending the injection angle at transfer closing. Probably a mix of both is optimal.

speedpro

26th May 2018, 22:01

The MAP sensor was very useful on my 125 twin. The MAP signal was used to determine which cylinder was where in the engine cycle. Link are looking at doing the same thing but last time I asked it wasn't ready for release. Without the MAP signal being used to determine which cylinder was where I have had to mount a trigger disc and sensor on one camshaft to provide a "home" signal.

The Ecotron use of the MAP sensor is obviously well sorted as my engine produces hardly any vacuum but I suppose it varies as usual, just not by much. It still worked with 1.4BAR as well.

The only downside of my Ecotrons ECU was the lack of processing power to handle lots of revs and a little problem with a faint contact between circuit board and case which took me a while to figure out.

The O2 sensors supplied with my 4T kit were narrow band. They would have been OK for tuning once you were in the ballpark or if you wanted to track minor changes over time, I bought the Ecotrons ALM for autotuning and have found it to be very good. It has a useful "test" output for when you want to calibrate the connection to the ECU. Now I'm using a Link ECU that test function was very useful and the ALM and the Link are a near perfect match. Link have it as one of the options in their software but I used a configurable table to define what the Link was expecting at various Lambda outputs .

speedpro

26th May 2018, 22:10

The brown line between the two white coursers shows the small injector going lean before the larger secondary injectors take over. Probably needs a bit of injection angle end adjustment.

What I see in that diagram is Injector 0(Inj0) stopping and Injector 1(Inj1) starting and for a short time after Inj1 starts it goes lean. Nothing to do with Inj0 as it has stopped. What that tells me is that Inj1 was not actually injecting fuel initially. If you are still running a fuel supply "to" the injector rather than fuel being supplied from a rail with fuel continually passing the injector, you may have had a small amount of air right at the injector. Could have been fuel vapour caused by heat

speedpro

26th May 2018, 22:17

That looks lean as well. My 4T likes .85 or so Lambda and supposedly 2Ts like to be richer.

TZ350

27th May 2018, 04:22

What I see in that diagram is Injector 0(Inj0) stopping and Injector 1(Inj1) starting and for a short time after Inj1 starts it goes lean. Nothing to do with Inj0 as it has stopped. What that tells me is that Inj1 was not actually injecting fuel initially. If you are still running a fuel supply "to" the injector rather than fuel being supplied from a rail with fuel continually passing the injector, you may have had a small amount of air right at the injector. Could have been fuel vapour caused by heat

Interesting. You are right about the way I have the fuel going "to" the individual injectors and not a fuel rail so what you say is very possible. Thanks.

337010 337011 Ok who tipped these pictures on their side ...... :wait:

I had a look, the fuel lines slope upwards so any fuel bubbles get swept back to the tank by the fuel rails bypass.

Ulstermanone

27th May 2018, 11:04

I had so much trouble understanding how they were thinking but when i turned on my programming head it all clicks to be honest the truth is in the wording that is not very clear to be honest
End of injection is from the end of injection to the trigger pulse not TDC -Say you want to end injection physically at 180 deg and the crank rotating anticlockwise and the trigger pulse was 40deg offset ahead of TDC so normally you would think the figure should be 140 but infect its 220 --Trigger pulse comes first and then TDC and then End of injection all calculated from the trigger pulze
The faster you go to this has to increase by 12 deg for every 1000RPM roughly to keep the end point the same of physical injection
()
That i proved out on a 4 stroke and stalled it by reducing the angle
So when you set that trigger pulze offset most important either by scope or light with zero ignition advance to find TDC()
()
The Trigger to ignition adavnce is just a timmer offsett in the program the same as end of injection -just math
These things i figured out ok but so tired with trying to stop this software going into 4t phazing and can find a way to stop it
()
Thanks for the info as every little piece helps to understand the software that bit more

336999

VRS pickup with only one lobe on the flywheel.

I don't use the Ecotrons ignition only the EFI side for fuel injection.

I am interested because Ecotrons changed my two stroke software so I could use VE and Alpha-N table. I have not tried it yet so not sure if I will actually still have 2T software or they have just activated it as 4T.

I use a wide band O2 sensor a lot on my 2T for tuning.

337000

The brown line between the two white coursers shows the small injector going lean before the larger secondary injectors take over. Probably needs a bit of injection angle end adjustment.

A MAP measuring atmospheric pressure is pretty handy on a 2T for automatic RAD changes.

I am afraid I can't help much here as I only have experience with a single tooth wheel.

337005

Yes, I too had to make diagrams to understand what was going on.

I think the "end of injection angle" is supposed to be degrees before TDC but I suspect it may be degrees before the actual ignition sensors trigger point.

Anyway "end of injection angle" is when the injection ends, it starts earlier and earlier (degrees wise) as fuel demand and/or rpm increases.

I found the best position was 180 or BDC where the pipe is supposed to be sucking the hardest. Others swear by ending the injection angle at transfer closing. Probably a mix of both is optimal.

TZ350

27th May 2018, 12:19

I had so much trouble understanding how they were thinking but when i turned on my programming head it all clicks to be honest the truth is in the wording that is not very clear to be honest. Thanks for the info as every little piece helps to understand the software that bit more

Yes, its the problem with Cultural and Language differences making it difficult for Ecotrons and us. Still I like their product because it opens the door in an affordable way for anyone to learn about and experiment with EFI.

Ulstermanone

27th May 2018, 15:25

TZ350

27th May 2018, 17:08

I do like what they have done and yes very good for an affordable EFI
I started this engine project with someone else and as they went by the wayside had to find a two stroke injection kit of some sorts and this seems to be the one
The Engine i have is a new design and injects low pressure into the bottom of the barrel/cylinder and fires every time but it has valves !
()
i will keep working away with what i have and see if i can come up with why it is phasing

Your 2T project sounds very interesting. I am sorry to hear you are having problems with the EFI system.

This Russian unit sounds promising. I see they use http://tunerstudio.com/index.php/tuner-studio for tuning both the EFI + DC spark ignition systems.

The SmartEMS light in aluminum milled case start 205 usd
wire harness with all connectors 68 usd
5-axis milled throttle body starts 110 usd.
Remaining sensors possible get from us or from any local shop which sell automotive or ATV components.
We can prepare complete instalation kit by customer specs.

We used before ecotrons, but had problems with system openess and sometimes it burn out. So we developed our own. We can develop electronics of any level of complexity, if it worth. Says in other my company sharing the same building we make avionics http://uav-siberia.com/en/catalog/avionika/

In our EMS project we decide save on software development. So everything what can be programmed in http://www.tunerstudio.com/index.php/tuner-studio is available. All algorithms and data tables.

Ignition part of our system could give you much more tuning options than Ignitech. And using 158 grammes Nissan Denso spark coils give you possibility burn out
sheet of office paper with spark.

We make our EFI + DC spark ignition compatible with http://tunerstudio.com/index.php/tuner-studio

So it completely open for experiments

http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=70738&d=1523558332
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=70739&d=1523558549

TZ350

28th May 2018, 06:40

................

Please have a look. At moment we have most of documentation in Russian, but going to translate on English, German and French soon.

http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=71655&d=1527425811
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=71656&d=1527425857
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=71657&d=1527425884
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=71658&d=1527425914

40cc model engine
http://www.reaa.ru/yabbfiles/Attachments/GF40.jpg

https://www.youtube.com/watch?time_continue=57&v=h3btzJ3bYLM
Some components looks rude, but they are more reliable than nice looking parts. We dont tested EFI at higher than 10000 rpm, but dont think it will a problem, espetialy using few nozzles.

Note: O2 sensor can be used in learning mode and disconnected afterwards. If correctly placed survive in 2-strokes for about 150 hours only.

Easiest way to get additional info is push me by e-mail

Valeriy Rutkovskiy
jbiplane@gmail.com

Ulstermanone

31st May 2018, 02:22

A lot of good and interesting stuff there that is for sure
Have any of the ones you know of on the site done an RS125R Honda with the kit ?

TZ350

2nd June 2018, 16:14

Have any of the ones you know of on the site done an RS125R Honda with the kit ?

No, not that I know of. I am still trying to find a way to get good drivability with EFI on a highly strung 2T like a RS125.

TZ350

3rd June 2018, 17:17

My first 2T EFI attempts were with an air cooled Suzuki GP125 engine and they don't have power valves. Made 31 RWHP @ 12250 RPM but still had the throttling problem below 25%.

337065337063337064337062337066

The first air cooled cylinder had direct through the B port and under piston injection. The second air cooled cylinder had under piston injection and injection across the A and B port entrance at the crankcase. I liked that arrangement, it gave promising results.

Flettner has talked about something similar, two primary injectors firing against the air flow in the B ports and secondary's in the A ports but with them all firing when the trapping efficiency is peaking and the motor is making real power. This arrangement would keep fuel away from the exhaust port when the trapping efficiency was not that great and air was spilling out the exhaust.

The water cooled cylinder has B port injection but squirting against the air flow. All the cylinders have three physical injectors but only two logical injectors as the B port injectors are fired together. The fourth picture shows the underside with the piston at TDC.

I have tried a lot of different combinations, primary injector in the inlet, in the crankcase, in the B ports with the secondary in the alternative injection ports. And all sorts of other combinations like firing from one side of the crankcase across the top of the flywheels and directly into the incoming inlet air.

The least successful was direct inlet injection from the outside (the 5th picture), my favorite was under the piston and horizontal across the transfer ports but that is difficult to arrange with the water cooled cylinder. But under piston for the slow injector and injecting in the B ports against the air flow makes good power and looks to be more economic than a carburetor too. With EFI there is much less of a fuel puddle on the dyno deck beneath the inlet. With a carb there is a much bigger puddle.

Along the way I have learnt a lot and figured out most of the puzzle but I am just missing that last piece of the jigsaw, how to account for randomly changing air flow through the motor below 25% TP. It seems that the more highly strung the motor the more unstably changeable the air flow is below 25% throttle position.

Its like trying to sail an unstable "P" class learner yacht in gusty changeable wind conditions, its much easier when the wind is steady and consistently from one direction.

337067

I am hoping that a MAP sensor in the crankcase and an Arduino Nano interpreting what it sees might be able to make sense of the air flow below that troublesome 25% throttle position.

TZ350

3rd June 2018, 17:19

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Vertigo+FI+wiring+.JPG

Item 17 is a combined pressure (vacuum?) & temperature intake sensor.
The exploded parts pics don't indicate where it is fitted.

Interesting that they are only using a MAP manifold absolute pressure sensor and a inlet air temperature sensor in the inlet. MAP and inlet air temperature, that is the same as my Ecotrons system so there is some hope.

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Vertigo+FI+a.JPG

Single point injection, after the throttle body and straight into the reeds.

This is where it gets interesting, 300cc cylinder with a single injector spraying into the reed block.

For myself I have several rules of thumb for 2T EFI. (a lot of this I have learnt from Flettner and Speedpro).

The longer the squirt duration the easier it is to get it right, so use the smallest injectors possible.
A long squirt mimics a carb.
A 360 deg squirt would be ideal especially if it coincides with the engines point of maximum charging efficiency.
Inlet injection maybe Ok for reed valve inlets but it is not so good for rotary valve engines. I have tried this.
There is a sweet spot for timing the finishing of the squirt. Usually somewhere around BDC to TPC.
Cylinders 250cc or greater are easier to get right.
MAP sensors have a settling time 2 - 6ms and they get confused if things get to busy.
Less than 9,000 rpm and you only need 1 injector. Because a small injector up to 9K rpm still has enough time to get the job done.
Above 9,000 rpm and your going to have to quickly start thinking about two stage injection using a small and big injector.
Injectors in the "B" ports are aimed downwards against the air flow.
Or better yet, if its physically possible, from the back aim the injectors horizontally across the bottom of the "B" and "A" ports.
For two stage injection, the single small injector is aimed under the piston for homogeneous mixing.
Alcohol based fuels are much more forgiving of changeable air flow, because they can be run real rich during moments of crappy air flow.
The more industrial the engine and/or application the easier it is to tune properly.
The more the engine depends on symbiotic reinforced wave action for making its power the harder it is to tune below 25% TP.

A EFI Honda RS125 engine would be a challenge to get throttling properly for negotiating corners.

Way back in the Olden Days, when we used to race with carburettors, we'd tune them to idle well, then lower the slides so they wouldn't/couldn't.

That is good info, tells me something about the minimum fuel required on closed throttle over run.

TZ350

3rd June 2018, 17:49

.
I have enjoyed a bit of success today.

Used EngMod2T to simulate a series of runs so I could look at the variations in crankcase pressure just to see if there is a consistent change that can be measured and reflect changes in air flow through the motor.

These are pressure ratios, absolute crankcase pressure divided by atmospheric pressure.

337124

This series of runs were taken at 8,000 rpm and is where the engine is really starting to get on the pipe.

The objective today was to see if the Arduino could read the MAP sensor and output a sensible result.

337123 337125

MAP sensor plugged into a spare injection port in the crankcase and the laptop and volt meter setup to monitor the Arduinos (true) analog voltage output.

The Arduino program looks for the highest and lowest pressure and the average for each cycle.

Then it outputs the sum of the average plus the difference.

337122 337121

Flashed the bike up and gave it a couple of blips. The analog voltages coming out of the Arduino look to be in the ball park and changed in a way that reflected real pressure changes (read, air flow) in the crankcase.

Its looking good for tomorrow. When I will connect the Arduino to the EFI CPU's MAP input.

With the new simulated MAP sensor input I expect the fueling to get messy but as long as I can use ECOCAL to data log some of the EFI CPU's output including the MAP trace I will be happy, ecstatic if it looks like it is the answer to seeing the un predictable air flow through the motor at less than 25% throttle position.

Fingers crossed.

jato

3rd June 2018, 18:49

Top effort TZ...I'm sure many people are following your work with great interest and admiration!

TZ350

4th June 2018, 12:44

.
Ok, another little step along the way.

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Gave the Arduino concept a try out today.

The EFI CPU was still running on only the Alpha-N map so I expected it to run fairly badly (to rich) but only really wanted to see what the crankcase pressure readings looked like and whether it looked like it might be useful for seeing changes in air flow at low throttle settings.

Fired the Beast up and gave it a few blips.

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Map sensor = Green line, TPS = Blue and RPM = Brown.

The MAP sure looks responsive enough and the numbers make sense.

It looks like we can now see real time changes in air flow at throttle settings below 25%.

The next move is to re do the mapping to include a VE table (may take a week) and see what the drivability looks like.

I am starting to feel hopeful.

speedpro

4th June 2018, 18:07

I would still have a bottle of wine on standby

Ulstermanone

7th June 2018, 02:08

Thanks for the reply
I have race many many two strokes and mostly GP machines
The RS125R witch ran from 1995 to 2004 most upgraded to an Air box system that gave a few psi of booster pressure and maybe would make below the 25 percent a bit more stable ?
()
I been building a Moto3 machine but its a lot different and soon to be taken for its first track day

crbbt

6th July 2018, 22:56

So I was mentally designing an engine I don’t have the money to build.

Thinking about the issue of when the fuel injectors will delivery fuel when not require.

Which got me curious. When the fuel supply is cut off but the air supply isn’t. How do the rpms respond?

I’m guessing a bit of a lag due to their being mixture in the crank case.

TZ350

7th July 2018, 17:33

When the fuel supply is cut off but the air supply isn’t. How do the rpms respond?

I’m guessing a bit of a lag due to their being mixture in the crank case.

That is a good question. How many rotations before the wet fuel on the walls in the crankcase and inlet tract is consumed at WOT.

It must be several rotations at least. Previous comments by those who have studied it are, that it takes 5-6 revolutions to completely change all the air/fuel mixture in the crankcase with fresh. So with diminishing fuel available from the crankcase walls you would think at least 2-3 revolutions at full load and WOT after the fuel supply is cut dead.

If you find an authoritative answer someplace I would be interested in what they have to say.

TZ350

7th July 2018, 17:43

More Dyno adventures .....

Had a chance to try the Arduino MAP simulator today.

RPM brown line, TPS blue and Arduino MAP simulation is the Yellow line.

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The Arduino uses a MAP sensor to measure crankcase pressure and looks for the maximum and minimum pressure and outputs the difference as a simulated MAP value to the EFI's CPU.

Bike sounded good and was even starting to show signs of improved drivability.

I was rely starting to enjoy myself laying consistent runs and making little improvements with ignition/fuel and PV adjustments.

Things were going real well, on the home run I thought, then I heard the dreaded dyno death rattle...... :(

Quick as a flash, in with the clutch and let the beast coast to a stop.

(&^%%$#$#^+_!!! could be the problem this time.

Turns out that it had drunk all its cooling water during 20-30 runs.:Oops: .... wasn't expecting that .... :facepalm:

Have not taken it apart yet but I suspect that small pressure drilling I put in a while back may be leaking or the head "O" ring. Not many other possibilities.

......:crybaby: ......

I would still have a bottle of wine on standby

...... :drinknsin

Well I need that bottle of wine. Just as things started to show glimpse's of the promised land I got the dyno death rattle.

Found the water had all disappeared. Expecting the cylinder and piston to be toast I took the top off. Turns out the cylinder is ok but it had run the bigend. Looks like the water washed the oil out and ruined the brg. Piston is toast from banging the head, I guess that was the rattle I heard but the head is Ok.

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TZ350

15th July 2018, 11:27

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Blue line = RPM. Brown line = LamWO2. Pink line = Injection pulse width. TPS = 100%

Cursers are both at the same TPS, RPM, Alpha-N load, and Injection PW.

On the left the engine is coasting down with the throttle held open and steady, LamWO2 a little lean, engine picks up at about 7,000rpm when air flow matches Alpha-N fueling and accelerates back to full power and rpm.

A little lean in reality can be an indication it is too rich to fire.

Left and Right sides both pass through the same Alpha-N map cells. Nath88 clued me into this. The air flow is different, there is much more air flow on the right than the left. After the exhaust wave has collapsed it does not re-establish until the motor has been firing again for a bit. The motor coasts down until the airflow matches the fueling at that point on the Alpha-N map (TPS/RPM) and the motor starts firing again and re establishes the wave action in the pipe.

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For the same RPM and TP throttle position you can have very different air flows through the motor. It all depends on the strength of the wave action in the pipe. The wave action collapses when you throttle off for a corner and takes some time to re establish itself after throttling on again. This is where those pesky 4T's get the jump on you at the track.

Alpha-N is a bit ridged as it only works with RPM and TPS so it cant flexible adjust the fueling because it cant see changes in airflow.

VE volumetric efficiency works with RPM and MAP or MAF and so it can flexibly adjust fueling because it can see changes in air flow.

But the problem is that all the EFI systems I have seen are aimed at 4T's and all of them don't have an easy way to identify changes in air flow through a high performance two stroke motor. Ie a 2T motor that is heavily dependent on its pipe for its performance.

A work around is required to marry a 4T EFI system to the needs of a 2T. Traditional 4T ways of measuring air flow are not appropriate for 2T's so some other way of doing it is required.

Ecotrons 2T tuning software only has the Alpha-N map available and other EFI systems like link have both but for any system some sort of work around is required to make them useful for two strokes.

speedpro

15th July 2018, 18:30

We need to be careful that we don't criticize Ecotrons for not being able to do something they never intended to do. Their focus, the one that attracted us, was the supply of cheap engine management systems. Being cheap there are limitations or restrictions.

TZ350

15th July 2018, 19:29

Their focus, the one that attracted us, was the supply of cheap engine management systems.

That is true. I love that they are making EFI systems affordable for budding experimenters. I could easily afford a Link but I would rather be able to add to affordable EFI 2T experimentation by finding a way for the Ecotrons 2T system to be used with high performance 2T's.

We need to be careful that we don't criticize Ecotrons for not being able to do something they never intended to do.

I am pretty sure Ecotrons intend to sell 2T EFI systems.

The Ecotrons 2T software is basically their 4T version with the VE table disabled because according to the Ecotrons tuning manual the MAP sensor (and I guess any MAP sensor for that matter) becomes confused when used in a 2T inlet tract.

They say that Alpha-N is sufficient for 2T's, well it might be on some bigger or more pedestrian 2T's but as we now know, it is not sufficient for a 2T that relies heavily on its pipe to make power.

I have asked for the VE table on my copy of Ecotrons 2T tuning software to be enabled so I can try my own approach to measuring airflow in a 2T.

I am not asking for Ecotrons to solve my tuning problems, I don't think they understand 2T's well enough to be able too anyway and that is Ok.

I only want the tools to work with for myself, which is an active Alpha-N and VE table.

I doubt it is difficult to re activate the VE map in their 2T tuning software.

Maybe they are just not interested.

speedpro

20th July 2018, 20:16

husaberg

22nd July 2018, 01:40

I've been thinking about a carburetor lately. I need one for my scooter. I thought about a conversion to EFI but it's already a mission and I have an EFI project already.

Anyway, thinking about the various circuits and where in the load/throttle range they have an effect it struck me that possibly an EFI system could be setup very quickly to mimic a carburetor. The huge fuel tables with all the load cells are really only a benefit if you want to very precisely control fuel for emissions. If you only want to race then emissions aren't the concern.

What I thought was for the load ranges, say TPS, simply go with 0% 10% 25% 50% and 100% and say 4-5 rev values, say idle to redline with 4 intermediate values. You could let the software take care of calculating the amount of fuel between actual specified values in the cells. The whole fuel map might only have 20 cells. I'm going to try it on my FZR once I get back to playing with it. If it doesn't work I'll just reload the last good config and carry on.
Riley Will mentioned that when someone set up a succesfull efi system on a gp bike all they did was use the fuel flow map from the carb and then overlaid into the efi.
they said it worked just as well as the carb and was not overly jerky in response like a 2t could be at the time with EFI
He put it down to the fueling on an EFI being too perfect where as a rider is not used to perfect fueling.

Hondas race PGM4? or what ever it was called, had a base map loaded in tuned by honda for all the kit parts, but had adjustment to fine tune it with 4 or 5 separate screws that roughly corresponded to the normal carb tuning idle pilot needle and main jet.
prior to that there was a similar aftermarket system that was totally tuned with trimpots and screws i think it was call the injec or something like that

TZ350

4th August 2018, 16:28

.
Ecotrons sells a two stroke EFI kit, the problem with their kit is that it only allows for the Alpha-N tuning control protocol.

The problem with Alpha-N which is a TPS/RPM map it does not allow for possible changes in air flow at the same TPS/RPM setting. Alpha-N maybe works on basic industrial and low powered 2T's, anything that does not rely on its pipe for power.

Alpha-N is great for power and all positions where the air flow is predictable but totally useless for drive-ability on a highly tuned two stroke.

On a high performance two stroke the wave action in the pipe collapses when the throttle is closed. When the throttle is opened again the noise comes back immediately but the strength of the wave action and therefore air flow through the motor takes some moments to build up again.

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Same TP throttle position and RPM but different airflow's due to the different strengths of the wave action in the pipe. Alpha-N floods the motor when you are trying to exit the corner.

Alpha-N is only good for near wide open throttle power when the motor is singing and the airflow is consistant. For drive-ability out of the corners a VE map RPM/MAP manifold absolute pressure or similar protocol is required that accounts for changes in air flow induced by the pipe.

Making power has been easy but drive-ability has been my stumbling block for a long time and I did not know what was making the tuning so difficult.

Now I know a Alpha-N map on its own is not enough and that I also needed a VE map to get drive-ability out of the corners.

For the last few weeks I have been trying to get Ecotrons to switch on the VE map in my 2T software for me but it is like pulling teeth and very frustrating. Dealing with their help dept is the best reason I can think of for not going anywhere near Ecotrons. I have found conversations with them often become circular.

I would have liked to have continued with the Ecotrons, because it is like an old friend and you can forgive an old friend their idiosyncrasies.
338050
But it might be time to move on because I have recently found a Arduino based EFI project called "Speeduino" that sells add on boards to convert the Arduino Mega 2560 to a EFI CPU and they supply open source firmware to go with it.

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The Speeduino add on board also has a development area where you can add your own IO and change the Arduino software code to suit too, so very flexible.

Its aimed at cars but it also has a 2T option and a VE table. I should be able to modify the software to get a timed crankcase pressure reading for a sample and hold MAP value. For the next step in my 2T EFI project it is just what I need.

https://speeduino.com/wiki/index.php/Speeduino

The continuing EFI story, now using a Speeduino has moved to a new thread, see below and follow the link.

Moving on from Ecotrons, Ecotrons is past history now, and I am moving forward with Speeduino for my 2T two stroke EFI project.

speedpro

15th September 2018, 19:10

I've just rebuilt my Yamaha scooter. With the ignition set more or less standard it really barked down low but detonated at about 1/2 throttle. The pickup mount is slotted so I pulled it all apart and retarded the timing about 4-5 degrees. It still runs OK down low and now takes throttle, to the point the front gets light. Given the time and effort to change ignition timing I was looking at an Ignitech but then decided to see if my Ecotrons GPz250 kit I got for my FZR would be useable. I picked off the ignition pickup, tapped and plumbed in a fitting to fit the map sensor to the intake manifold, and hooked it up to one of the ignition coils i used on the FZR. Fired the scooter up still using the stock ignition but with the Ecotrons dummied up next to the scooter. Got plenty of spark and the laptop indicated what I was expecting with reasonable MAP values and a RPM indication that seemed about right. The only software change was changing the number of teeth on the trigger to "1". I'll need to play with the trigger offset parameter to get the ignition to line up with the standard timing marks. Easy to do with it dummied up and the stock ignition actually running the engine. I'll take the fan shroud off, put a timing light on the Ecotrons ignition and adjust away on the laptop until the timing marks match the stock ignition settings.
Still haven't used full throttle, not even close. Maybe a bit over half and 110K not a problem.
The other good thing is the stock engine is rev limited to 9,200rpm but this motor is good for 11,000rpm so I'll take the opportunity to bump the rev limit up.
I haven't been too impressed with Ecotrons but hopefully simply handling the ignition at lowish revs it should be good. Now I just need to find somewhere to mount it.

speedpro

8th October 2018, 21:55

I mocked it up but came across a problem where, if the ECU case was grounded, or I used the -ve of the bike battery and 12V from the bike battery it stopped the motor running when I plugged in the crank trigger connector. Running completely separately with just the crank trigger connected and the MAP sensor I could adjust the settings to get the spark to line up with the standard system. For some strange reason I couldn't alter the timing with the main ignition map.
I've decided to use the Ignitech DCCDIP2 system I had used on my MB100. It doesn't have a MAP sensor input but does have a TPS input. It's 0-5V(ish) so I'm going to connect the MAP sensor to it and use what Ignitech call the 3D ignition map, except that instead of the variable voltage coming from the TPS it'll come from the MAP sensor. Should work fine.

husaberg

3rd December 2018, 17:41

Rob too Late now but late model fords have digital output MAP sensors.

FORD DIGITAL MAP SENSORS
Ford BP/MAP sensors (barometric pressure/manifold absolute pressure) also measure load but produce a digital frequency signal rather than an analog voltage signal. This type of sensor has additional circuitry that creates a 5 volt "square wave" (on-off) voltage signal. The signal increases in frequency as vacuum drops.

At idle or when decelerating, vacuum is high and the BP/MAP sensor output may drop to 100 Hz (Hertz, or cycles per second) or less. At wide open throttle when there is almost no vacuum in the intake manifold, the sensor's output may jump to 150 Hz or higher. At zero vacuum (atmospheric pressure), a Ford BP/MAP sensor should read 159 Hz.

the BP uses a reference presure atmospheric no ones says it has to be the actual atmosheric it could be tapped to pipe for instance or to crankcase it could be referenced as a go no go and nor
Another one i found was a ICP which is a piezo based analog sensor that detects acceleration of load its used on ford diesels to detect condition where additional fuel pressure is needed such as acceleration
https://blog.fordiesels.com/2013/09/04/what-is-an-icp-sensor/
it works in conjunction with a IPR or injection pressure regulator

Ford powermax diesels also use a ebp or exhaust back pressure sensor
https://www.amazon.com/1850353C2-Exhaust-Pressure-Pigtail-Connector/dp/B0192I70Z8 $24 usd
http://www.diesel-dave.com/vehic/manual/vt1/vt118057.htm

TZ350

3rd December 2018, 20:23

Rob too Late now but late model fords have digital output MAP sensors.

Thanks. those sensors you have shown may be very useful. The problem with Ecotrons was that in their two stroke Alpha-N offering there was no place for a MAP input to influence fueling, analog or digital. And unless I paid $500 USD they would not tick the box for me that would allow me to also use the VE table which is influenced by a MAP input. I am happy to be away from them, they are hard work.

The Speeduino allows me to modify the board and change the Firmware code itself, it is a whole lot better proposition for a developer to work with.

husaberg

3rd December 2018, 20:34

Thanks. those sensors you have shown may be very useful. The problem with Ecotrons was that in their two stroke Alpha-N offering there was no place for a MAP input to influence fueling, analog or digital. And unless I paid $500 USD they would not tick the box for me that would allow me to also use the VE table which is influenced by a MAP input. I am happy to be away from them, they are hard work.

The Speeduino allows me to modify the board and change the Firmware code itself, it is a whole lot better proposition for a developer to work with.
Sorry i thought it did only not analoge signal out of the sensor.
So what was the difference between the 2t and 4t one?
Have you seen the Delco units the old Comerdores used to run they have a Eprom the VN on has Map they are $60 out of oz and about $50 for the Eprom burner.
plenty of other cars had them nissian pulsar etc