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Alternative ignition system 4 years 6 months ago #25577

  • Daro
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Ok Kawboy osci beam passes from left to right that's time and i will set it to different values per each square, you can always see this in top left corner on the picture. Also voltage varies, this time beam travels up and down and shows how much it changed in given time. One thing though i hope its not getting boring, probably half of the readers have fallen asleep till now, so if it is we can cut to the chase and get to the practical part straight, because there is still some stuff to talk about so let me know.

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Alternative ignition system 4 years 6 months ago #25578

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A little history. I finished my auto mechanics apprenticeship back in 1978 at the age of 22, got my mechanics licence. Spent 3 years of my 5 year career as a tuneup mechanic. Using a Snap-on scope after a tuneup and reading a multi cylinder pattern is commonplace for me although having the ability to "adjust " the Time/Voltage reveal on the scope was not possible with the Snap-on unit.
I'm looking forward to seeing how the different igniters accommodate the required dwell time to charge the coils at different rpm's and produce a healthy spark with a reasonably long duration.
2 stokes benefited from CDI ignition but fail to develop a long duration spark. Inductive coils build a longer duration spark but can fall flat on their ass at high RPM's and high compression.
So as previously mentioned, Looking forward to seeing where you take this topic.

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Alternative ignition system 4 years 6 months ago #25579

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Standard kawi igniter makes 0,8 millisecond spark when using standard spark plug and have managed to push the spark through at ten bar only under 1500 rpm above that, energy from coil have gone over ceramic or debris on it in to the ground. Already at this stage there was no spark in the chamber at all but the plug outside had spark. Between 1500 and 7500 rpm dwell time reduced from 10 to 2 milliseconds. I remember long ago I had made similar test and the figures varied slightly from that, on different igniter, maybe the setup was little different or due to lower supply voltage. After installing iridium spark plugs things got slightly better.
Like said before, some people have feeling that the performance of the engine is better after installing iridium plugs. I personally think that this is absolutely true, I'll explain my observations. Lets take a look at how spark is "born". The charge from ignition coil is moving towards its destination, the electrodes of the spark plug. Only to find in there a gap, instead of closed circuit but the energy must go somewhere so it starts to ionize the gas in order to build plasma and be able to escape. In order to ionize the gas high voltage must first build the field of energy around electrode to free electrons from the atoms which will then become ions and when there is enough of theme to bridge the gap ionization process rapidly starts. Now I stop. We look back to standard plug with big electrodes and compere to iridium plug electrode form, which i significantly smaller so to my understanding the energy required to create force field to break electrons to ions on small electrode is a lot less than on the large electrode. I got this idea once when building stainless steel model of ball gas tank form refinery. I was welding tiny stuff with barely 15 amps and i notice when my electrode was little blunt i could just hold the arc alive before I stuck it on to work piece, but with very very sharp electrode it was merely a task, so you see the similarity ? Also on the example from above at 1500 rpm there is just not enough energy to ionize the gas with large electrode probably because the surface is so big and you need more force to rip electrons free and with tiny one everything is more concentrated. Yeah this are just some thoughts when I'm welding at work ;) Kawboy. Any ways all this information I write here are being collected over the time from various sources and literature, also I like to say that I'm by no means any professional electrician electronic or engineer working for development sector of any kind. I'm making my own experience in various fields, building stuff, traveling, being a dad of two or even cooking. All of this is a challenge I'm happy to take on any time, and like I wrote before learn from it and share the experience gained. So here I am now, talking to you about breaking electrons free from the gas atoms. Anybody want to add something here or have further questions regarding iridium plugs ?

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Alternative ignition system 4 years 6 months ago #25580

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AHHHHHHH the man's a TIG welder by trade. I held 9 tickets for 15 years at the nuclear plant. Try welding 18 gauge carbon steel @ 15 amps and then contaminate your tungsten. Stop welding and regrind the tip. Been there done that. But you're right The arc no longer ionizes well.

what is column E "volts" ?
It is my understanding that the Darlington transistors add dwell (energized time of the primary) as the rpm increases which is contrary to your findings. Wonder why?

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Alternative ignition system 4 years 6 months ago #25585

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Kawboy column E Volts is for my own reference only. When testing it indicates the rpm simply by reading the voltage applied to the motor, bench psu have digital multi meter so its easy. First module i have tested and actually it was running in the bike was the Hella 5DA 006 623-051. I didn't know what to take so i when for it because of the manufacture name i know for many many years. Initial testing did not reveal the great weakness of this unit. So first it was a success because i have manage to build my own ignition and fitted to the bike, however the happiness didn't last for very long, after discovering that the bike have slight stumble up on quick throttle, or in stand still reeving up. This is how the "research" was born ;-) . So after getting over the disappointment i started to look at the problem ahead of me in more theoretical way, because it was clear with out it there will be no new ignition i so desperately want it to have. After looking at the trace i suspect, there is no current control on this unit because current draw is gradually rising with no indication of something taking any action visible on the trace. The unit charges the coil with: I=U/R, I=0.4V/0.05 Ohm = 8 Amp. After i added 1 ohm resistor in series with the coil current dropped to 5 Amp at the engine speed around 500 rpm maybe. Second thing is that up on sudden acceleration it skips one pulse as the result engine develops noticeable stumble, like when the idle to mid range lucks fuel. And so it was Game Over for Hella for me, because i have expected more from such old manufacture, oh well.





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Alternative ignition system 4 years 6 months ago #25596

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Next unit tested was 03SKV906 equipped with MC3334 chip. With this device i manage to reach 5000 rpm only and modification of the internals was actually out of the question, like i wrote before i want it to have something ready otherwise i would make one my self. I suspected that the pickup coil is not compatible with it and as result it starts to switch to dwell at high rpm's.



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