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Re: my simple ECU

Posted: Sun Sep 21, 2014 5:12 pm
by russian

Re: my simple ECU

Posted: Sun Sep 21, 2014 5:35 pm
by ivan141
Might be a good idea to have your gauge's indicate error's more clearly, but otherwise a nice little addition.
Is there anything the ECU can do with EGT, or is it more for logging/tuning purposes?

And finally: Did that thermocouple survive it's baptism of fire? It didn't look to great there at the end of the vid.

Re: my simple ECU

Posted: Sun Sep 21, 2014 5:45 pm
by russian
Actually up to eight gauges - but yes, just a gauge for now, but I am open to your ideas :) What kind of logic could be possible on top of EGT value?

If only other fancy inputs were same trivial as this one! MAX31855 does _everything_ here - all you do is consume 4 bytes via SPI, that's it.

It actually could be that the fire is the reason of the "open circuit" error - the wires were simply twisted together and the baptism by fire might have separated/contaminated them enough. I will re-shoot the video once I get some uber-cheap probes from China.

Re: my simple ECU

Posted: Sun Sep 21, 2014 5:54 pm
by ivan141
I suppose you could get a lot of carbon buildup sticking bare wire in open flames like that.

You could have an error indication somewhere inside the gauge I suppose, although not every sensor input will have error reporting capabilities off course.

I will be using the MAX31855 for my reflow controller myself, it struck me as a potentially useful IC for exactly what you are doing with it (EGT), so I ordered a few along with my MAX9926's.
Turned out they are also the go-to IC for building reflow oven controllers.

Re: my simple ECU

Posted: Mon Oct 27, 2014 10:25 am
by Matthijs
Is that actual copper wire you use to connect the EGT sensor? It is not supposed to be like that..
Just order some cheap EGT sensors from ebay for like 4 of 8 bucks each.
Than you get a metal nozzle around it to protect it from flames.. a k-type sensor can handle 1200C but the wires itself can only handle ~200C or so.
AND you get the propper wire material which are made out of the same metals as the EGT sensor it self which is mandatory to get a correct reading.
(i've build myself an EGT interface with the same chip ;))

Re: my simple ECU

Posted: Mon Oct 27, 2014 10:29 am
by Matthijs

Re: my simple ECU

Posted: Mon Oct 27, 2014 11:47 am
by russian
Matthijs wrote:Is that actual copper wire you use to connect the EGT sensor?
No.

The "sensor" is the spot where two different wires couple. If you use same wires, there is no coupling spot thus no sensor thus the decoding chip (which I would not call a sensor but I am not a native speaker) would report "short" condition.

What you see on the video is a purposely-made thermocouple wire. It's the coupling which is executed poorly :)

I've got some cheap eBay K-probes, just never got the time to try them :( Too many little things on the TODO list.

Re: my simple ECU

Posted: Mon Oct 27, 2014 11:52 am
by Matthijs
Yeah it is not a real 'sensor', I agree =] The video isn't that clear so I thought I give a heads up just to be sure =]

Re: my simple ECU

Posted: Mon Nov 03, 2014 1:44 am
by russian
http://www.youtube.com/watch?v=PhIWAPaUnYM

automatic Honda with a blown HG was not serving me well, finally I have a functioning test mule. I hope to figure out better cold start this year and get some miles on this vehicle.

Re: my simple ECU

Posted: Mon Nov 10, 2014 8:16 pm
by russian
First time starting a cold engine, big day for me!

https://www.youtube.com/watch?v=UqBzuZEqcEo

Still not exactly perfect, probably need some tweaking of the coefficient curves and probably needs a new feature of extra fuel for first 10 seconds of running.

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