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Thread: Speeduino 2T EFI Project

  1. #136
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    Hi Rob I got bored last night and started reading ypur Speeduino thread on the Speeduino forum
    I havent got to the end but i see most of the stuff i mentioned you have tried or was covered.
    But i did find this that looks like its available as an add on to the Speeduino.
    http://speeduino.com/forum/viewtopic...b7a7c&start=10
    Which is the deceleration fuel cut. If you havent tried that yet.
    The other thing i found was that most cars have idle control valves also function on normal over run high revs no throttle open to bleed in air to a four stroke.
    The idle air control valve works at idle and during deceleration. In other words, any time you take your foot off the pedal. During deceleration, the computers on most fuel injected vehicles do a “fuel cut” procedure where they stop operating the fuel injectors to force the engine to lose RPMs. However, since the pistons are still moving up and down, the engine still needs an air supply. The idle air control valve opens during deceleration to provide that air. Some people think that the idle air control valve fine tunes air/fuel mixture as you’re driving. It doesn’t. In fact, if you view a scan tool while driving, you’ll see that the PCM isn’t giving ANY commands to the idle air control valve. Take your foot off the pedal and you’ll see commands start up again during deceleration and fuel cut mode.
    Fly by wire systems do this directly with the throttle nowdays though.
    As an aside MotoGP bikes actually use this feature to help control engine braking i think its called a "kicker" it works as afar as i know really well and simpler method than a over running sprag clutch at stopping the wheel locking from compression breaking.


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  2. #137
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    Another respose to deceleration Surge
    http://www.powercdi.com/manual/combu..._bangs/en.html
    Hes expressily fobids cut and paste.


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  3. #138
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    Quote Originally Posted by husaberg View Post
    Another respose to deceleration Surge
    http://www.powercdi.com/manual/combu..._bangs/en.html
    Hes expressily fobids cut and paste.
    Very very interesting article. A great description of four or six stroking combustion in a two stroke.

    He is wrong about there being low pressure in the crankcase at low throttle openings. In reality at low throttle opening there is a low migration of fresh mixture through a partially contaminated crankcase in which the pressures are relativly high. In fact near atmospheric. Counter intuitively, at low throttle you have higher average crankcase pressure than you do at open throttle. You have the lowest average crankcase pressure at full open throttle.

    Crankcase pressure represented by the black line is very nearly atmospheric and at much higher rpm, much higher than the 250's he is talking about it barely makes it down to an average of 0.9 bar. At 13,000 rpm like my GP it gets down to about 0.75 bar. That is not low pressure like we would associate with the inlet of a four stroke at low throttle.

    Click image for larger version. 

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  4. #139
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    Quote Originally Posted by husaberg View Post
    But i did find this that looks like its available as an add on to the Speeduino.
    http://speeduino.com/forum/viewtopic...b7a7c&start=10
    Which is the deceleration fuel cut. If you haven't tried that yet.
    Thank you for finding these things for me.

    I have tried DFC "Decal Fuel Cut" where the fuel is cut completely on over run. When you stand beside a DFC two stroke bike on a dyno that has just shutoff from a full noise 13,000 rpm pull and it seems to take forever to wind down you start to wonder about the wisdom of cutting off its lubrication. Fuel cut or no fuel cut the problem of 1 or 2 below remains the same when you throttle on again. Anyway it was not the answer to my drive ability problem.

    My problem is that at any Throttle position and RPM combination there are two distinct fueling requirements that are entirely different from each other.

    In both scenarios the "average" crankcase pressure is much the same.

    1:- when the pipe is sucking air through the motor.

    2:- when the pipe is "NOT" sucking air through the motor.

    The problem is how to tell the difference between 1 and 2 and fuel accordingly.

    I think I know the answer, the "average" is not much different. But the "difference" between the highest and lowest pressure each cycle is much less for 2 than it is for 1. And its this change in difference that I think will indicate relative changes in airflow through the motor.

    I think this is the answer:-

    Click image for larger version. 

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    When there is a big difference between max/min crankcase pressure you have big air flow and when there is little difference you have little air flow.

    You heard it here first.
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  5. #140
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    Quote Originally Posted by TZ350 View Post
    Very very interesting article. A great description of four or six stroking combustion in a two stroke.

    He is wrong about there being low pressure in the crankcase at low throttle openings. In reality at low throttle opening there is a low migration of fresh mixture through a partially contaminated crankcase in which the pressures are relativly high. In fact near atmospheric. Counter intuitively, at low throttle you have higher average crankcase pressure than you do at open throttle. You have the lowest average crankcase pressure at full open throttle.

    Crankcase pressure represented by the black line is very nearly atmospheric and at much higher rpm, much higher than the 250's he is talking about it barely makes it down to an average of 0.9 bar. At 13,000 rpm like my GP it gets down to about 0.75 bar. That is not low pressure like we would associate with the inlet of a four stroke at low throttle.

    Click image for larger version. 

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    I agree i think he wrote the original in Italian.Still interesting he claim to be able to tune most of it out with Ignition and i suspect pv as well.

    Quote Originally Posted by TZ350 View Post
    Thank you for finding these things for me.

    I have tried DFC "Decal Fuel Cut" where the fuel is cut completely on over run. When you stand beside a DFC two stroke bike on a dyno that has just shutoff from a full noise 13,000 rpm pull and it seems to take forever to wind down you start to wonder about the wisdom of cutting off its lubrication. Fuel cut or no fuel cut the problem of 1 or 2 below remains the same when you throttle on again. Anyway it was not the answer to my drive ability problem.

    My problem is that at any Throttle position and RPM combination there are two distinct fueling requirements that are entirely different from each other.

    In both scenarios the "average" crankcase pressure is much the same.

    1:- when the pipe is sucking air through the motor.

    2:- when the pipe is "NOT" sucking air through the motor.

    The problem is how to tell the difference between 1 and 2 and fuel accordingly.

    I think I know the answer, the "average" is not much different. But the "difference" between the highest and lowest pressure each cycle is much less for 2 than it is for 1. And its this change in difference that I think will indicate relative changes in airflow through the motor.

    I think this is the answer:-

    Click image for larger version. 

Name:	Crancase pressure cycle.jpg 
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    When there is a big difference between max/min crankcase pressure you have big air flow and when there is little difference you have little air flow.

    You heard it here first.
    I think total fuel cut would be fast death as the carb still feeds air and fuel even with the throtle closed through the pilot and other circuits on return
    I was musing more a 10-30%. I think it needs a Map which if set with the correct perimeters can tell the difference or a Maf which directly measure real flow.
    Something similar is mentioned to your last bit in one of the threads i read last night.
    I found some other stuff last night including some stuff from Nath88.
    http://www.msextra.com/forums/viewtopic.php?t=65104

    http://www.oocities.org/tech4tdi/pages/maf.html
    http://www.msextra.com/forums/viewtopic.php?t=65104
    https://www.sciencedirect.com/scienc...76610217337578

    GM MAF sensors output a frequency proportional to airflow as do Toyota MAF sensors. Ford, for certain and I'm pretty sure, Bosch sensors, output a simple voltage propertional to airflow.
    .
    You can mount the Maf or restrict the airflow and recalibrateor get the flow table if you cant find one on the net it using aflow bench
    All of this makes you appreciate how clever a carb really is


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  6. #141
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    I've been measuring this AFR on overrun on my scooter lately. On overrun it goes super lean, over 20:1, and as the engine drops to idle the AFR returns to whatever you have it tuned for. This was easily repeatable simply blipping the throttle or slowing down on the road. As soon as the throttle was opened even a small amount the mixture returned to normal. It was almost like a Decel fuelcut on the fuel injected FZR which I've also played with. This is a 4T engine with a genuine Mikuni TM33 carb. A 2T will work exactly the same I would expect.

  7. #142
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    Quote Originally Posted by speedpro View Post
    I've been measuring this AFR on overrun on my scooter lately. On overrun it goes super lean, over 20:1, and as the engine drops to idle the AFR returns to whatever you have it tuned for. This was easily repeatable simply blipping the throttle or slowing down on the road. As soon as the throttle was opened even a small amount the mixture returned to normal. It was almost like a Decel fuelcut on the fuel injected FZR which I've also played with. This is a 4T engine with a genuine Mikuni TM33 carb. A 2T will work exactly the same I would expect.
    Would some of that be why Foul strokes need accelerator pumps while two strokes strong intake pules only need shrouds on the Needle Jet?
    I mentioned the Delco ECU a heck of a lot of the 100's millions that where spent on it were in the control of vacuum advance and lean off for cruising.
    The Ecu are $60-100 now not really pertable enough for bikes but for their time pretty clever and there is all sorts of free software to tune them in real time.

    Rob Might remember years ago i posted about my mates Mb100 that ran with a Pumper carb of a jet ski the carb was 38mm and it worked perfect other than on long over run
    I think of these carbs as a primitive fuel injection
    The carb was perfect but it wasnt able to tell the difference if the throttle was open or closed it just pumped fuel based on crankcase pressure alone.
    So what happened was you would open the throttle after a long run in to a tight corner like a hairpin and it would load up for a second or two then come in with a bang once the excess fuel cleared.
    Years later i found a story that jennings wrote where he had the same issue and it was able to be resoled with a simple check valve.
    Karts dont suffer from it as they dont really shut the throttle like a bike does.

    Oil and Maf sensors
    Mass Air Flow Sensor Investigations
    No dealership or service provider, when contacted, has ever been able to provide us with evidence to support this "myth," and in fact, our investigations have revealed that even authorized dealerships are simply speculating and do not have the test equipment necessary to know whether the sensor has failed or why. In the last 7 years, we have had more than 300 actual sensors sent to us by consumers with documents showing dealerships claimed our product had caused them to fail. Microscopic, electronic and chemical testing revealed that none of these sensors were contaminated by K&N oil (K&N Detailed MAF Sensor Test Results). What is perhaps the single biggest clue to what is going on is that over 50% of these sensors sent to us were not broken in the first place for any reason. Click here for more information on how this may happen.


    “A lot of dealerships do not have the ability to test MAF sensors,” said K&N Vice President of Product Development and Engineering Steve Williams. “If you’re going to diagnose something you should show whether it is at fault or not. What they have is what we call the plug and play process. That is where they go through and download some codes and guess. The consumer then gets hit with a bill for components that were never a problem. K&N always tells people the facts.”
    K&N Engineering Research and Development Department
    K&N Engineering Research and Development Department
    There is no silicone in K&N oil and testing has shown that MAF sensors will operate normally after being immersed in K&N Filter oil.
    https://www.knfilters.com/MAF/massair.htm

    Even if it needs a squirt after every ride
    https://www.crc.co.nz/Mass-Air-Flow-...-0081ef6e9f4d/


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  8. #143
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    .
    Trying to apply 4 stroke thinking to solving a 2 stroke issue is as silly as trying to understand a woman's needs by applying a male point of view, both internal combustion engines are entirely different species behaviorally.
    .
    .
    .
    1:- air flow when the pipe "IS" sucking air through the motor.

    2:- air flow when the pipe is "NOT" sucking air through the motor.
    .
    .
    .
    1 & 2 are the issue and there is a whole range of meaning attached to "sucking" and that is the real problem to address.
    .
    .
    The Ecotrons could not do drive-ability well on my bike with its Alpha-N only map. It is impossible for Alpha-N to do drive-ability well for engines with high performance pipes, because of the wide variance in air flow. So some sort of modified MAP or MAF value is needed. Currently I am exploring the possibilities of using the Speedy with its firmware that I can re write to suit my needs. I am looking at a modified MAP reading to adjust the Alpha-N table. MAF is plan "B".
    .
    .
    What I need is a sure fire and affordable way to measure crankcase pressure with < 1ms settling time and a 2.5 or 3.5 bar absolute range.
    - Team ESE -



  9. #144
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    Quote Originally Posted by husaberg View Post
    Another respose to deceleration Surge
    http://www.powercdi.com/manual/combu..._bangs/en.html
    Hes expressily fobids cut and paste.
    This is interesting because I have seen it on my MAP gauge, random high MAP values as the engine is in over run or idling. Deceleration Surge looks like a good explanation for it.

    It takes about six crank revolutions at WOT and full power to total refresh the crankcase with completely new mixture. The plan is when in over run or idling to smooth the MAP value over a number of revolutions.
    - Team ESE -



  10. #145
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    Click image for larger version. 

Name:	Alpha-N Table.png 
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    This is a Alpha-N table. Each cell delivers a "FIXED" amount of fuel for that set RPM/TPS position.

    For example the fixed amount of fuel delivered for 7.5% TPS at 9,000 RPM can not be both correct for when the pipe is sucking a lot of air through the motor and when its not.

    Below 10/10 ... 10,000 RPM / 10 bar BMEP you might get away with it with some engines and a few people have. But above 10/10 the air flow changes over a much greater range than delivering just a fixed amount of fuel can cope with. Alpha-N works well on WOT because air flow is predictable but fails when the air flow becomes variable due to pipe resonance collapsing or not at lower throttle settings.
    - Team ESE -



  11. #146
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    There is quite a treasure trove in the links Husaberg has posted.
    - Team ESE -



  12. #147
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    Quote Originally Posted by TZ350 View Post
    .
    Trying to apply 4 stroke thinking to solving a 2 stroke issue is as silly as trying to understand a woman's needs by applying a male point of view, both internal combustion engines are entirely different species behaviorally.
    .
    .
    .
    1:- air flow when the pipe "IS" sucking air through the motor.

    2:- air flow when the pipe is "NOT" sucking air through the motor.
    .
    .
    .
    1 & 2 are the issue and there is a whole range of meaning attached to "sucking" and that is the real problem to address.
    .
    .
    The Ecotrons could not do drive-ability well on my bike with its Alpha-N only map. It is impossible for Alpha-N to do drive-ability well for engines with high performance pipes, because of the wide variance in air flow. So some sort of modified MAP or MAF value is needed. Currently I am exploring the possibilities of using the Speedy with its firmware that I can re write to suit my needs. I am looking at a modified MAP reading to adjust the Alpha-N table. MAF is plan "B".
    .
    .
    What I need is a sure fire and affordable way to measure crankcase pressure with < 1ms settling time and a 2.5 or 3.5 bar absolute range.
    That tallies with these readings from what i posted of a industrial 115cc 2 stroke with no decent pipe.
    Click image for larger version. 

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    Also with KTM the map sensor feed is the bare spigot on the back of the cylinder just above the base
    Click image for larger version. 

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    They call it the Vacuum connection part.
    https://www.bikebandit.com/oem-parts...55&sch=1067495


    Here it is here on the oil pump
    KTM Crankcase Presure Sensor

    https://www.bikebandit.com/oem-parts...55&sch=1067500

    The flywheel is saw toothed multi pickup just like yours too.


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  13. #148
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    Click image for larger version. 

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    The changes in air flow are reflected by changes in the height between maximum and minimum crankcase pressure. This is where I am looking to get my MAP value from. It would be interesting to know if that is what KTM are doing.
    - Team ESE -



  14. #149
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    Quote Originally Posted by TZ350 View Post
    Click image for larger version. 

Name:	crankcase pressure trace.JPG 
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    The changes in air flow are reflected by changes in the height between maximum and minimum crankcase pressure. This is where I am looking to get my MAP value from. It would be interesting to know if that is what KTM are doing.
    Well We could ask Fletner
    I seen some very similar values mentioned elsewhere on a thread i read somewhere with a jetski or Snowmobile.
    my gut says maybe it should go at least another 1/2 bar either way on the pipe, what does the modeling say on the sim?
    With that output i posted from the GM sensor it can detect deceleration vs acceleration with the output and goes lower again with a shut throttle on over run than idle. no mater what sensor output either frequency or voltage is used (at least in a 4T situation)
    The KTm ecu is about $450 US
    The Sensor $40
    So its really quite inexpensive for new tech by KTM standards
    I will only take a mater of time before someone has a peek to see what the fuel map looks like and tells the world.
    From memory at the time there was a lot of the talk about the oil pump which was Japanese having a lot of the patent tech
    I can recall if its keihin or Mikuni but as the sensor is mounted to the oil pump the sensor might be also from them?
    The oil pump output is ECU controlled according to the blurb.

    1. What are the benefits of new TPI models?
    • Automatic setting for altitude and temperature
    • The 2 Stroke engine oil mixer,does not need premix fuel anymore, More precise engine performance, improved linear power delivery
    • Reduced fuel consumption, There is no waste of fuel from the carburettor
    • Simpler use, easier engine start, no change jetting required,The TPI range does not require the fuel and oil mixture


    2. Are the Husqvarna TE250i & TE300i EFI (Electronic Fuel Injection) models differ from the model KTM EXC TPI 2018 ?
    No, Husqvarna and KTM use the same technology, the same drive engines.
    Husqvarna comes standard with a switch to change the injection map, Husqvarna also has a different concept of air filter (Airbox) with which the engine running and feeling remains specific to Husqvarna.

    7. How much is fuel economy savings on injector models?
    From the conditions and driving style, the savings are about 30%-40%.

    8. What fuel / oil lubrication ratio is used?
    The amount of 2t of oil constantly adjusts the computer’s ECU, depending on the engine rev , and the scale itself is constantly changing.
    But the average fuel usage is ,oil is 80: 1

    16. Is it possible to change the ignition map and engine power settings?
    There is an alternative map that is named Map Switch and programmed in the ECU engine. This other map is something of lighter features (softer engine characteristics) It is not possible to create your own ignition and injection maps.
    If you watch this it also has a simple diagnostic port.


    but wait
    from ktm
    ow using accepted and understood parts it all came down to processing the information and getting the mixtures right. Quickly. The window of time for the injector to be open and getting the large amount of fuel a two-stroke needs is the challenge, especially in even smaller displacements we are told. Plus when a two-stroke has a “flame-out” inside the combustion chamber, it can take up to 50 strokes for the engine to recover. This was a big issue in high RPM, low throttle times. For instance when you are going down a hill with the engine revving and then you give it a little gas. Making the throttle response as good as that antiquated carburetor was very difficult. There is not a lot of time for the computer to decide how much fuel and when to shoot it from one stroke to the next since the conditions inside the two-stroke engine can change drastically and very suddenly. Even small things like having the engine’s crankcase pressure sensor and fuel injectors mounted so that vibration was not affecting them were lessons learned in testing. Luckily the new 2017 engine was designed from the beginning to eventually have a non-carbureted fuel system so it would vibrate less and also be able to produce as much electrical power as would be needed.
    Read more at https://dirtbiketest.com/fresh-dirt/...F1q5sgXMoYl.99
    In the end the answer, for now, was actually quite simple. In partnership with Synerjet the ECU was developed and tuned and that has been the difficult part in getting a base system to work off of. Now more tuning and testing can take place to see where FI will go on two-strokes.
    Read more at https://dirtbiketest.com/fresh-dirt/...F1q5sgXMoYl.99

    of synerjets site

    only 2t one i can find is this
    http://w.synerject.com/en/2-3-wheele...di-system-p9-5
    combined temp and presure sensor 4mm direct fitting
    http://w.synerject.com/en/2-3-wheele.../tmap-30-p23-5
    One more piece i just found the KTM has a lambda in the pipe
    Click image for larger version. 

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  15. #150
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    Quote Originally Posted by TZ350 View Post
    Click image for larger version. 

Name:	crankcase pressure trace.JPG 
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    The changes in air flow are reflected by changes in the height between maximum and minimum crankcase pressure. This is where I am looking to get my MAP value from. It would be interesting to know if that is what KTM are doing.
    I love this graphic and what you have indicated in it.
    In the one it is appreciated well where the pressure begins and it is not in the TDC (because this occurs: at that point the inertia of the incoming gaseous mass is greater, than the speed of the piston creating empty) (in the 4S that is the delay of closing of intake valves "a few degrees after the BDC").
    I know I'm wrong, but I still think that taking the pressure of the crankcase through a hole located below the exhaust port and controlled by the skirt of the piston, is a simpler method that will allow us to know how much is the quantity aspirate

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