[mbardeen]

Flash, not to belabor the point, but I think tama was only using that as an example.



Continuing to discuss it takes the thread off topic, which if I understand tama correctly, is a basic sensor reading module and display with alarms. The exact sensors don't really matter too much at this point, as they will just convert some analog reading into a digital form readable by the arduino.

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[flash]

no worries. but, as there is a difference on voltage, resistance, and such for various sensors, it may or may not complicate things, and working out solutions for unessential sensors seemed to be a waste. i've gotten buried in minutia before, and it has killed projects. i'd love to see this one work, though for myself, if it did, i would not be putting it in the cluster, but rather likely to the left of the headlight switch. there is a large unused area there, now that i moved my switches to where they really belong.

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[tamathumper]

Varying voltages, resistances, and even curves simply become a "map", and could be user-selectable based on the type/brand of sender unit being used.

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[flash]

assuming the board has on it the devices necessary to accept the varying inputs, yes. otherwise, you would have to duplicate the senders with something the board could accept. i have that problem now with the oil temp. the gauge i have takes a thermocoupler. it cannot be grounded. most gauges want a thermistor, which is grounded.

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[MB968]

[quote name='Eric_Oz_S2' timestamp='1381623635' post='150680']

Egt is very useful on a supercharged car. Not sure why flash thinks otherwise. For starters it can help with tuning to ensure there is the right balance between ignition and fuel.

[/quote]



Agree with Eric. Found it to be very useful when tuning. On my N/A Mazda, I found that Mazda had mapped the stock engine resulting in a lot of variability in EGT depending on the engine rpm/load conditions. at lean cruise the EGT would run over 1500F sometimes approaching 1550F. Most street conditions it ran around 1400F, whereas under <acronym title='wide open throttle'>WOT</acronym> it would drop to around 1300F.



When I was tuning the engine with the supercharger, knowing what the factory did, I was a little more at ease with pushing via the combo of a/f and timing, the EGT close to 1500F for lean cruise. For most street driving my mapping ran in the 1400 range. My tune under boost conditions gave EGTs in the 1200 range.



And after all the tuning, it was a good health indicator, and good piece of mind to see these same numbers when driving. Kinda like a water temp gauge rather than an idiot light. It's nice to know when you're pulling that trailer up the mountain, that you can look at the gauge and see how the systems doing. And, if it's getting out of the norm, you can do something about it ahead of time.

Tama, nice project. I'm pretty much thumbs when it comes to software/electronics. But, if you perceive anything I could help with, let me know.

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[flash]

sure, when tuning. pretty much useless though after that. an A/F on a wide-band is far more useful, even when tuning. an EGT is too slow to respond to tell you anything useful, unless you are pushing the edge of the envelope, which would never happen on a street car, unless you were a complete moron.

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[Lear35A]

Not a perfect analogy, but in my NA 4 cyl fuel injected airplane, I monitor (and use) EGT digitally displayed data for all 4 cylinders. The fast response probes give a virtually instantaneous indication of any temperature changes. On one occasion a sudden increase in one cylinder's EGT caused me some concern and I returned to my home airport. Subsequent inspection showed a small piece of debris had partially plugged the FI nozzle causing the lean condition. I for one would not be comfortable flying without EGT info. In a car...well it sure wouldn't hurt.

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[MB968]

[quote name='flash' timestamp='1381706721' post='150697']

unless you were a complete moron.

[/quote]



You don't have to be a complete moron to have unexpected things happen such as Lear mentions. Otherwise why have ANY gauges. I'm a believer in O2 sensors, I had O2 and EGT on my boosted KL engine. I wouldn't be without either on a built engine. Unfortunately, the WB O2 doesn't tell you what the ignition is doing. EGT is a combo of both. You can have reasonable O2 readings and still have dangerously high EGT's that could kill an engine.

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[flash]

but you won't be able to react fast enough to do anything about it. the EGT is too slow to prevent damage. even with the best sensors, it takes 8 to 10 seconds of extreme lean condition to raise the reading enough to tell you there is a problem, and you have to be watching it to know. it only takes less than 2 seconds of the same condition to cause detonation and blow a hole in your piston.



long before that, our ECU will tell you it is too lean. there is a code just for that. i know. i've triggered it. we have a very primitive ECU and it still has that capability. all current systems are much more sophisticated, with built in warning mechanisms that will tell you when you are too lean.



an EGT gauge on a street car is just a geek's masturbation gadget. you should never be anywhere near a need for that, and there are a lot of other things that will tell you that you have a problem long before that will.

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[MB968]

As I said in my post, there are conditons other than too lean that can give high EGTs. O2 doesn't help with these. And my experience with EGT's is more like Lears, and I quote from his post "The fast response probes give a virtually instantaneous indication of any temperature changes." I guess you disagree.

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[Eric_Oz_S2]

Flash, I think you should start a new thread on Egt, rather than running this one off track.

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[tamathumper]

Ideas and offers to assist are still welcome, and thank you for the e-mails and PMs already received. Those interested in helping with the project have been contacted and development will continue on a "Version Control" capable system which will allow for multiple developers. Updates will be posted periodically as significant progress is made.

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[flash]

the mixture cannot be lean without the O2 picking it up in a reading. that's just plain simple.



but, i agree that further discussion of the EGT is diverting things a bit. however, the development of the device, and it's interest level of the consumer, would be largely determined by its functions. an EGT won't be useful to anybody in a street car, any more than an A/F would. it might be useful to somebody who is tuning, or somebody in a race car, where you are pushing the envelope more, and seeing higher exhaust temps than you ever would on the street.



we have had turbocharged cars for decades, and not one of them has had one of those. why? because the computers on board are capable of dealing with conditions outside the parameters. in over 30 years of tuning engines, many of which have been forced induction, i have only used an EGT 3 times, and in none of those cases did i ever get near needing it. there are just too many other things to tell me when something is wrong, and in an application where i can only choose 1 gauge at a time, and have to do something to get to that reading, EGT would be the last thing i would be looking at. i would look at oil temp long before that.



but carry on.

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[tamathumper]

My cell phone doesn't take a very good video, so things look a little blurry and washed out, but this little screen looks fantastic in real life. The programming environment is complete, the hardware is hooked up, and the first compile-load-test is shown below.



Still miles to go, but so far, so good.



https://www.youtube....h?v=-HTVRyAyvLU

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[Lear35A]

Oh, I like it already. Trying to find small concave bottom enclosure. So far no luck, but you never know.

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[tamathumper]

Button "array" configured and working on the menu system...

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[DaveN]

Oh that breadboard takes me back - to the original! Keep up the work, I'm keen to see what becomes of this. Is this controller like a raspberry pi?

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[mbardeen]

It's an Arduino -- lower-spec than the Pi. Has a microcontroller, rather than an ARM processor. It's thought of for low cost prototyping and is open-source.



The Pi is thought of as a tiny computer.

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[tamathumper]

The Raspberry Pi is a small computer that has to boot an operating system, usually some version of Linux.



That takes far too long for an automotive application, upwards of 30 seconds or more from what I read.



The Arduino is a programmable microcontroller that's available almost instantly when you apply power, and the 4D display Goldelox processor also only takes an instant to boot once programmed. The micro SD card has to be mounted, but that seems to be taking just a fraction of a second as well.



This needs to be available the second you turn the key, or very shortly thereafter - like the rest of the gauges.

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[tamathumper]

Interface basic functions complete. While the menu options themselves will change over time, the basic functions of scrolling the menu selector, performing the correct function when selected, and going "back" are implemented.



https://www.youtube.com/watch?v=QZyA-IEt...detailpage

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