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Post by deffie83 on Sept 2, 2020 14:30:58 GMT
Hello everyone, Matt,
just found the rabbit ECU project and it sounds awesome to me, even if not perfectly mature its an impressive piece of work.
I'm quite fascinated by it and I'm thinking to use it on a heavily modified motorbike prototype powered by a Rotax V990 V-Twin aspirated engine with dual spark per cylinder, MAP and indirect injection.
One of the features I'm missing mostly from the factory ECU is the combustion closed loop, as the bike has no lambda measurement ability (and it wouldnt be wideband anyway).
But from what I'm seeing in the docs there's capability for just one AFR gauge while I would like to read and control each cylinder individually, is there any way to do this ? and do you think the Rabbit ECU would be appropriate for such engine, ie, dual spark per cylinder control ?
Oh and I would love to play with all the fine tuning capabilities the rabbit ecu has, its impressive, also being able to use MAF and MAP together would be awesome.
Thank you and congratulations for this excellent piece of work!
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Post by Admin on Sept 5, 2020 6:17:03 GMT
Hi,
Thanks for the compliments - yes I think that's fair to say the ECU is gaining many nice features but isn't mature yet :-)
There is provision for two oxygen sensors and the closed loop controllers to work independently for each bank. Just for 14.7 target of course.
I think the Rabbit ECU is appropriate - I would just need to know a little more about the crank angle sensor and RPM range to confirm.
Dual spark are you meaning a split spark like on a rotary? It could be done...
Please feel free to share any more info here.
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Post by Deffie83 on Sept 8, 2020 22:09:03 GMT
Hi, Thanks for the compliments - yes I think that's fair to say the ECU is gaining many nice features but isn't mature yet :-) There is provision for two oxygen sensors and the closed loop controllers to work independently for each bank. Just for 14.7 target of course. I think the Rabbit ECU is appropriate - I would just need to know a little more about the crank angle sensor and RPM range to confirm. Dual spark are you meaning a split spark like on a rotary? It could be done... Please feel free to share any more info here. Hi Matt, thank you for your reply, willing to take a deeper look at the code and wondering about the teensy version (implementing dbw in a 20 years old motorcycle would be amazing 😄, it would be a quickshift forerunner too) is there a repository for the teensy version ? About the engine specs, the crank sensor is a hall effect sensor on the rotor of the stator. The rotor has about 48 teeth with a key made of one or two missing. 10500 rpm would be enough, actually the limiter is set to 10100. Still have to find how the key is positioned in respect to the TDC and the exact number of teeth, with these rough specs, one could expect about 8400 pulses per second and a granularity of 7,5 degrees, which looks like a quite large number, but I think there are already strategies in the firmware to raise this granularity, by using both edges of the pulse or by estimating rotational speed, are they ? 😇 Actually the engine is having just the crank sensor and I’m somewhat wondering on how it can determine which of the two revolutions its currently happening, speed difference from intake/compression to ignition/exhaust ? Correlation to intake vacuum ? Don’t know. However, luckily the same engine was also used in racing bikes (aprilia rsv) with an additional (hall effect) cam sensor on the intake cam, and i can easily add such sensor just by opening the cam cover. About the dual spark, simply put there are two spark plugs for each cylinder (and so four coils/spark plugs total), I think their ignition is simultaneous, however i’m gonna investigate about it, by asking or by checking with a scope. About the closed loop, why do you say just for 14.7 target ? I was hoping on eventually multiple runtime selectable rpm/load/afr tables with wideband afr 🧐 Thank you, Giacomo. |
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Post by Admin on Sept 13, 2020 11:48:13 GMT
Hi Giacomo,
I believe you can observe the crankshaft acceleration on cranking to determine which 360 degrees of the complete 4-stroke cycle you are in and not use a cam sensor.
I haven't done this but I don't think it would be too difficult with the fast ARM processor ;-)
Right now I only implemented closed loop code for simple switching oxygen sensors that's why I say 14.7 only.
With the crank sensor resolution I think the 48 teeth is plenty. There aren't any strategies to improve granularity for ignition timing in Rabbit ECU.
I guess you could do such a thing and have ignition timing accuracy to within a very small fraction of a degree if that is a requirement...
Right now the Rabbit ECU for Arduino code is open source as is the hardware.
The Teensy code is available under license for a fee but the firmware hex will always be available free of charge.
Cheers,
Matthew
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Post by Ben Mundackal on Jan 10, 2021 14:55:03 GMT
Hello Matt,
i would like to get that teensy EFI system. i have a small project Honda CX500 (80 degree V-twin).i would like to install EFI. would you able to help me? This is my first project.
Thank you
Ben
benmundackal@gmail.com
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Post by Admin on Jan 12, 2021 11:29:55 GMT
Hi Ben,
I'm not too familiar with your setup to be honest. Did you want to install just EFI and use the original ignition system?
Alternatively if you want EFI and spark timing you will need to install a crank angle sensor and toothed wheel.
EFI only you will need some kind of adapter to get a clean rpm signal from the ignition system.
Maybe some wiring diagrams would help do you have them?
Cheers,
Matthew
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