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Thread: Ecotrons Engine Management

  1. #211
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    No thanks, it's not my bag.

  2. #212
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    Quote Originally Posted by Drew View Post
    I'd start spraying as soon as the inlet ports closed or a little before. If it's hitting the top of the piston it's gonna mist up real nice I would have thought. That being my understanding of why direct inject was more efficient.
    Quote Originally Posted by TZ350 View Post
    Yes, reportedly works well at low speed <10k rpm, maybe you could put some numbers together to see how likely it is at 13k rpm.
    Quote Originally Posted by Drew View Post
    No thanks, it's not my bag.
    Drew faith based intuition is great for giving you a direction to look in and being able to put (rough) numbers to something like TeeZee does can tell you if you are on the right track or not. Numbers can save you from a lot of wasted time.

    Time at 13k rpm = 4.6ms for a complete 360 deg crank revolution.

    Transfer opening to closing 130 deg. 1.7ms.

    From exhaust port opening to closing 200 deg. 2.6ms

    From exhaust closing to ignition. (with ignition timing 18 deg BTDC). 72 deg. 0.8ms.

    Pressure in the cylinder ATDC greater than the 3 bar fuel injection pressure 90 deg, 1.2ms.

    So somewhere between 1.7 and 2.6ms for injection, 0.8ms for fuel homogenization.

    2-3ms required to open and close the injector 2-3ms required to deliver the fuel another 2-3ms or so to homogenize it.

    Total time required:- 6-9ms

    Drew, is there enough time to get everything done? I am picking not, and I am picking TeeZee doesn't think so either.
    Factual Facts are based on real Fact and Universal Truths. Alternative Facts by definition are not based on Truth.

  3. #213
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    With EFI, "Time" is King.


  4. #214
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    Quote Originally Posted by Nath88 View Post
    Quote Originally Posted by TZ350 View Post
    Attachment 329951

    Because there is a period between 6 to 7,000 rpm of violent oscillation just before coming onto the pipe. Even cranking the power valve down to ridiculous amounts did not help.

    Red line TPS
    Blue line O2 sensor
    Brown line Small injector
    Yellow big injector
    Top Green line is RPM
    Looks like you have a fair bit of lash in the drivetrain with the engine speed jumping around like that. At 15% throttle it looks like the switching between the small and big injector is causing the misfire, possibly injector settings are a bit squif and when it switches over it jumps richer or leaner. Is it just a straight RPM switchpoint with no hysteresis?
    At 50% throttle it looks like it's going too rich as the revs climb and pulsewidth goes up, then stops firing, revs fall, pulsewidth drops, then it kicks on again. I think the problem is in fuel delivery not gas dynamics. Guessing it doesn't do it with the carb? Food for thought.

    Also there is a big lambda delay on these things off the pipe and it always swings lean when misfiring. Is the motor on the rich limit/four stroking? Your lambda values look ok, but they can appear lean when air is short circuiting the motor. My motor has a 'rich' point between 4500-5500rpm, 50% throttle and up. I think it's the anti-resonance point of the pipe. Shows the same 12.6:1 AFR as other points but its on the verge of four stroking, heaps of blue smoke, similar to how 10.8:1 behaves (which is about the rich 4-stroking limit on mine when on the pipe). So i've tuned that area to be about 1.5 points leaner. I am yet to do a plug chop at that point to check, I'm yet to do any plug chops actually, luckily the YZ isn't too picky on mixtures.

    I put some hours on my thing on the weekend, did about 150km around the city and mountains with the new fuel system. It was running a fair bit richer for the same fuel pressure, so the pressure at the injector must be more constant. Also the VE table is starting to look how I would expect, a lot more natural and smooth, apart from the weird anti-resonance peak. Maximum injector duty cycle of 80% at 9200rpm, full throttle, 145km/h uphill. It used to do 150km/h with the carb on the flat, but I haven't leaned the EFI out past peak yet. Next on the list is to get the target AFR table right to maximise power, will probably do a bunch of plug chops to see what the motor likes, maybe hit up the dyno.
    There is a lot to think about here, I think you are definitely on the money. Very encouraging to hear about you success's with the YZ.


  5. #215
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    Quote Originally Posted by Nath88 View Post
    Took the bike for another ride last night. Leaned it out a fair bit in the high load areas, a little in the cruise range, and a bit past peak rpm. Made the bike very happy! Was going to be a short one but ended up cruising around the streets for about half an hour because it was running so well, bike never missed a beat. 'Lean' cruise is a funny feeling, it's very smooth, like a scooter, then when you open the throttle it just rolls into normal YZ250 in every way.
    Attachment 329972

    The VE table ended up looking like this, load areas tuned by wideband lambda feedback.
    Attachment 329979

    This is the exhaust pressure system in action. Just before the cursor position, I blipped the throttle to 20% and the motor didn't respond (no exhaust pulse = no fire), that's the area I need to work on the most, probably a bit rich at closed throttle at that RPM, lambda offers no useful feedback so it has to be tuned by feel. After the cursor, when opening the throttle to 20% for a little longer, the motor has time to clear, then the injector pulsewidth more or less follows the exhaust pressure. You can see it four-strokes a bit then runs clean. Then opening the throttle to 15% goes into constant light throttle four-stroking, again, fuel following the exhaust pulses.
    Attachment 329973
    Thanks........


  6. #216
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    Injector Position

    Attachment 331035 Attachment 331038

    Central injector fires through a slot into the underside of the piston.

    My favourite low speed injector position has been to fire under the piston. This seems to help enormously with fuel homogenization at lower and off pipe engine speeds.

    Attachment 331036

    My least favorite and less successful position has been to inject directly across the crankcase into the oncoming inlet air stream. During periods of air flow reversion fuel gets blown out the inlet. And also at higher speed low throttle there is not enough time for a small squirt of fuel to travel right across the crankcase for even fuel distribution.

    Attachment 331037

    Looking at a piston positioned slightly below transfer port opening the two clean spots at the edges look to me like marks left from air/fuel short circuiting from the A ports and washing the carbon away.

    When I showed this to Flettner and asked about injector positioning. He suggested an injector in each of the A and B ports.

    Attachment 331033

    Flettner suggested the B port injectors should handle the low speed fuel demand leaving only fresh air short circuiting from the A ports.

    And any short circuiting is most likely at lower engine speeds before the reverse pressure wave action from the pipe blocks the exhaust port as the motor gets up into the power band.

    At higher engine speeds when the motor is up on the pipe, then have the A port injectors chime in. That way with fuel injected into all four A and B ports the mixture should be pretty homogeneous. Flettner's idea sounds better than what I have been doing which is trying to combine two purely air streams from the A ports with two overly rich streams from the B ports and have them properly mix together in the cylinder.

    As for problems coming back on the throttle after shutting off for a corner Nath88 suggested that at less than 20% throttle the EFI ECU needs to be able to differentiate between when the engine is firing and the pipe is sucking and creating a higher bulk air transfer through the motor and therefor fuel demand verses when the wave action in the pipe has totally collapsed and much less fuel is required.

    The Alpha-N map can’t do this by itself, there needs to be some way for the ECU to tell if the engine is firing and the pipe sucking or not. Nath88 suggested measuring the return positive pressure pulse at the exhaust port. It is a great idea and I like it but unfortunately, I have not found a way to get my Ecotrons EFI software to do that.

    Flettner suggested measuring the internal pipe pressure at the dwell section in the middle of the pipe. He pointed out that the pressure must drop when the wave action collapses and that by using a VE table below 20% throttle/load and Alpha-N above that I might be able to train the ECU to recognize when the motor is firing and wave action in the pipe is increasing demand for fuel.

    I like Flettners idea of low speed injectors in the B ports and secondary injectors in the A ports that chime in when the fuel demand under full power/load requires all four injectors.

    Attachment 331034

    I have ordered more parts from Ecotrons and my next challenge is a lack of room and to figure out how to fit a secondary injector close to the power valve actuator.

    When I followed Nath88's very clever idea about using the return pressure wave at the exhaust port to see when the motor was firing. I ran into a problem, my ECU software averaged the low suction pulse and high plugging pulse and arrived at a lower average for on power open throttle compared to closed throttle. Makes sense when you think about it but I could not figure out how to get the ECU to make sense of it. Basically it needed to reduce fuel when the average pressure was higher and increase fuel when it was lower. This is opposite to the way EFI ECU's think.

    In the mean time I am going to get this Beast going again and try Flettners idea and see what sort of average pressures are in the dwell mid section of the pipe and if the EFI ECU can make sense of them.


  7. #217
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    Quote Originally Posted by Frits Overmars View Post
    What we need now are injectors that are small enough and fast enough.
    I have personally run an Ecotrons small injector at 13,000 rpm in my 125cc two stroke engine ... http://www.ecotrons.com/components/fuel-injectors/

    Quote Originally Posted by Nath88 View Post
    Quote Originally Posted by TZ350 View Post
    When I followed Nath88's very clever idea about using the return pressure wave at the exhaust port to see when the motor was firing. I ran into a problem, my ECU software averaged the low suction pulse and high plugging pulse and arrived at a lower average for on power open throttle compared to closed throttle. Makes sense when you think about it but I could not figure out how to get the ECU to make sense of it. Basically it needed to reduce fuel when the average pressure was higher and increase fuel when it was lower. This is opposite to the way EFI ECU's think.
    That's exactly the problem I'm having now... I've been experimenting with measuring the crankcase pressure instead of exhaust, just after transfers open. Under 25% throttle once on the pipe (7000 up) the pressure is lower than at 0% throttle... then over 25% the pressure starts going up. Which makes sense, the scavenge effect of the pipe drawing against the mostly closed throttle. But as you said, no good for a normal 4 stroke style ECU, it expects a linear input. I should put up some graphs of the data collected. Perhaps if you sampled the pressure before and after the transfers open then take the difference. The ability to write the code specifically for the engine is where KTM has a massive advantage.

    At the moment I'm working on modifying the ECU code to capture the highest peak of the exhaust pulse as the port opens. I think this will be a good indicator of how much wave energy has gone into the pipe. So far the best results have been with the exhaust pressure at the powervalve vent. The PV housing was acting as a damper, smoothing the pressure pulse so the ECU could catch the peak easily, signal was a bit too smooth so I'm trying other methods, trying to nail an analog carb feel on throttle transitions. If the code mods don't work out (I'm no programmer), back up plan is to use a 'precision peak hold' circuit on the map sensor, then using the ignition output to reset the circuit at the start of each cycle. You could implement this on your ECU easily enough.
    Quote Originally Posted by Frits Overmars View Post
    Quote Originally Posted by Nath88 View Post
    At the moment I'm working on modifying the ECU code to capture the highest peak of the exhaust pulse as the port opens. I think this will be a good indicator of how much wave energy has gone into the pipe.
    Another option would be to look at the highest peak of the exhaust pulse after BDC, i.e. the return pulse. That will be an equally good indicator of how much wave energy has gone into the pipe, and it offers the additional advantage of knowing when this return pulse arrives back at the cylinder. If it's too early, lower the EGT by advancing the ignition timing; if it's too late, retard the ignition timing. That way you'll have a truly intelligent ignition and you can forget about EGT.

    A lower compression ratio forcibly yields a lower expansion ratio; less combustion energy is converted into torque by the time the exhaust opens and more of this energy remains in the exhaust gas in the form of higher pressure and higher temperature. This remaining energy drives the exhaust pulses, improving cylinder filling for the next combustion event, and the next and the next.... This way a lower compression ratio can lead to higher power.

    The lower comp ratio also made engines less sensitive to piston ring groove wear and ignition spark strength, and it helped overrev, so the bikes became easier to ride.
    At the end of the lead-area the Aprilias had a compression ratio of 19,5. When lead was banned, this ratio was initially reduced to 14, after which it was gradually raised again. My personal preference would be to try even lower ratios in order to feed the pipe with even more energy.


  8. #218
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  9. #219
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    Links to a whole bunch of EFI projects. Mostly amature home tuners, and all great work.

    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

    EFI YZ dyno run https://youtu.be/UEQli7nuak4
    EFI YZ250 look around and first start up https://youtu.be/hOGZ5llowoU
    EFI YZ250 trail ride 1 https://youtu.be/1YG9ko8-Nwk

    Nath88?
    EFI first start up https://youtu.be/wIRF3VJUqBk
    EFI ride around the block https://youtu.be/4Zsz26QmfAU

    CVT EFI NOS and everything else https://youtu.be/A9d-atuQO7Y
    EFI and Turbo Snow Cat https://youtu.be/U1uz7gdS-cA
    SeeDoo Etec https://youtu.be/LhNHcy9si5o

    1975 Suzuki GT250 road bike fuel injected start up https://youtu.be/A7fONUsJQD4
    1975 Suzuki GT250 road bike fuel injected road test https://youtu.be/BePHcg5dNjw

    Fuel injected 1971 Yamaha R5 https://youtu.be/qzVHgHJ9PWI

    Athena Direct Injection https://youtu.be/h-F_IndOm5I

    BRC 250 EFI kart engine https://youtu.be/dNat9ZwWbq8
    BRC 250 EFI kart engine https://youtu.be/Kfx61bUOznc

    Racing EFI Vespa https://youtu.be/_sjx2i4xFlY

    EFI Banshee first start https://youtu.be/e1WHVVT6d9c
    EFI Banshee run https://youtu.be/eznxX_ndpII

    Direct injection https://youtu.be/IpjWi-0qTJg

    Will direct injection DI save two strokes https://youtu.be/ql2-wW0LuWY

    Orbital direct injection https://youtu.be/fIoB0zTeUAY

    EFI Dragbike Thailand https://youtu.be/VB6Q_fQQ_PY

    Mega Squirt YZ125 https://youtu.be/Di8FuHApLKA

    Aprilia RSi 125 EFI Part 1 https://youtu.be/S1xvr_VXzx4
    Aprilia RSi 125 EFI Part 2 https://youtu.be/j5FOUn7V3nc
    Aprilia RSi 125 EFI Part 3 https://youtu.be/WBaiMJb6ntY
    Aprilia RSi 125 EFI Part 4 https://youtu.be/pZl5KPwvm0s

    EFI 125 kart engine https://youtu.be/4D8WRjDxan0
    EFI 125 kart engine https://youtu.be/b1YbPdw00Ww
    EFI 125 kart engine https://youtu.be/r5ljaDdaH_o
    EFI 125 kart engine https://youtu.be/uexMJbtyZdU
    EFI 125 kart engine https://youtu.be/uzbSsYh8Z9w
    EFI 125 kart engine https://youtu.be/XIcX9-GsMGQ
    Fuel injected Kart https://youtu.be/R5_KlcefQ8k

    2017 KTM dyno https://youtu.be/8g0uSIisMtI
    2017 KTM demo ride https://youtu.be/nf1tfdUtjJI

    EFI CR250 https://youtu.be/VlHyRcmlLgU http://www.supermototecnica.com/2015/09/10/sviluppi-del-sistema-iniezione-diretta-indiretta-due-tempi/

    EFI YZR500 https://youtu.be/tNAtmKzqo9A

    EFI CR500 https://youtu.be/BskSxMoQrwA

    2T Nitro Engine visible combustion https://youtu.be/aO5Qkzlo2Kw
    2T visible combustion https://youtu.be/G7PSec7RjRw
    More 2T Visible combustion https://youtu.be/BrWpF6YiSDs

    Fuel Burn in a side valve 4T https://youtu.be/jdW1t8r8qYc
    4T Visible fuel burn https://youtu.be/31mtOdHGbB4


  10. #220
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    Looks like High Gain Tuning may have solved the issues that are holding me back and sell a kit for DIY two stroke EFI.

    http://twostrokemotocross.com/articles.php?id=336


  11. #221
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    Careful. This guy showed up on the RZ forums with a hiss and a roar, and lots of self promotion in a wayonly Americans seem comfortable with,. . . got upset when people asked questions (how dare they) and then disappeared never to be heard of. Note article 2011.
    I've been told. Dreaming`s free.
    Think I'll go, back to sleep.
    Everybody listen, voices in my head
    Everybody listen, do yours say, what mine says?

  12. #222
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    Auto tuning

    Hello
    Anyone know why I get this message when I want. To try
    Auto tune " ecocal can't find the auto tune table
    In the al2 file ?

  13. #223
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    al1 stack over flow.

    Resynchronise the initial constituants.
    I've been told. Dreaming`s free.
    Think I'll go, back to sleep.
    Everybody listen, voices in my head
    Everybody listen, do yours say, what mine says?

  14. #224
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    Quote Originally Posted by F5 Dave View Post
    al1 stack over flow.

    Resynchronise the initial constituants.

    Hello anyone know why I get this message when I try to
    open auto tune " ecocal can't find the auto tune
    table in the a2l file ?
    And what to do ?
    Thx claus

  15. #225
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    Quote Originally Posted by sidecar bob View Post
    Applying some quite basic arithmetic, 13,000 rpm on a two stroke, equals roughly 26,000 rpm on a 4 stroke as regards injector cycles. Maybe that goes some way to help explaining the anomaly.
    Absolutely

    Quote Originally Posted by jonny quest View Post
    I'm also very interested to hear more of your findings in your NSR250 porting. You actually lost power by opening up the ears of the exhaust port? You're either transfer limited, or major short circuit going on A transfers to ex port. You may find it beneficial to "bowl" out ex port right after window.
    Yes my first effort at porting the NSR cylinder lost power. And I think you are right about the reasons. I tried leveling the top of the exhaust port off by eye but totally stuffed up the exhaust port timing, got something like Ex opens 74 ATDC and to get the timing anywhere sensible I trimmed 2mm of the bottom of the barrel. The Ex was then 78.5 atdc and trans 122. To get the trans back to 113 I angled the A's up at 25 deg and the B's at 15 but the whole thing was a shambles.

    So I started again.

    Attachment 332289

    Quote Originally Posted by jonny quest View Post
    TZ350, we rev 250 4 strokes to 15,000rpm all day with a single injector in the throttle body. I'm comparing apples to oranges I know, but still... was shocked to think you need 3 injectors for 13k.
    There are actually only two "logical" injectors, one big one small. The two "physical" injectors in the B ports are there for symmetry of fuel distribution and are fired together as one Logical injector. I use three physical 124g/min injectors but the EFI CPU sees only two logical injectors, a 124g/min slow speed injector and one 248g/min high speed injector.

    But it is not about injector size but time available to get the injecting done. If you only have half the time, then you need an injector twice the size to get the job done. And you need a small one for tune-ability when there is plenty of time like <9k 2T rpm (equivalent to 18k 4T rpm) and a much bigger one to deliver much the same amount of fuel when time is getting short like above 10k.

    The reason you can't use the big injector for slow running is because an injector must be turned on for a minimum amount of time to get it completely open and controllable. And a big injector just spills to much uncontrolled fuel while it is opening for idling speeds and small throttle opening.

    15,000 4T maxed out rpm "Time" for an injection cycle is just about where my 2T is starting to come on the pipe and get going. A 4T has twice as much time to get things done so only needs an injector half the size of a 2T, ie something about the size of my slow running injector.

    It is "Time" not injector size that is the real issue with EFI.

    Quote Originally Posted by jonny quest View Post
    ... a single injector in the throttle body.
    Another issue with 2T EFI and throttle body injection is that unlike a carburetor which adds fuel to the air stream all the time, regardless of whether the air is being sucked in or blown back out of the crankcase ie fuel standoff.

    A fuel injector squirts fuel in discreet blobs. And is just as likely to add all the fuel to the air stream as its blown back out as it is to the air stream being sucked in. So there could easily be rpm patches where you could wind up with little fuel at all in the crankcase.

    This is less of a problem with transfer port injection. Where the bulk of the fuel is concentrated in the transfer duct and not the inlet tract where it can be more easily ejected. And will be one of the reasons why 2T EFI can show improved fuel efficiency over a carburetor.

    And another reason for injecting into the B transfers is that the bulk of charge short circuiting happens from the A ports and if there is little fuel in the short circuiting air then the motor is cleaner and more fuel efficient. Another win over the carburetor which would have loaded all the crankcase air with fuel. With a carburetor all blow back and short circuiting air loses fuel and pollutes the environment, with 2T EFI not so much.


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