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 Post subject: egt sensor
PostPosted: Sun Nov 16, 2008 12:50 am 
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I have started looking at EGT sensors. What I need to know is.... where to get a suitable sensor that will output a 0-5V signal to feed in to my DTA ECU.

I am a little confused WRT how an EGt sensor works.
is it a resistaive type that requires a 5V feed and outputs a voltage back dependant on sensor resistance/EG temp? Does it require other electronics due to V.small signal otput or sever non-linearity?

I have foudn that RS componenets sell K-Type thermocouples with a range up to 1100 degs - I hope they are suitable, woudl still need to source a clamping type nut for the sensor and sort out the other wiring/electrsonics

I hope to get teh exhaust manifold drilled & tapped for this on a combined runner section. not ideal but 4 off EGT's is OTT IMHO for my requirements.

Oh - I hope to feed this back to ECU for correction should "*bleep* happen" and to use it as a guide to where "lean best torque" is still safe. Basically where it is unsafe to lean off the fuelling due to EGT's.

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PostPosted: Sun Nov 16, 2008 4:53 am 
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Keep pestering me and I'll get off my Yaris and design a det/EGT correction circuit

After DVB-T2 P1 symbol detect/decode design the FFT should be trivial lol


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PostPosted: Sun Nov 16, 2008 9:23 am 
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Ok I will keep pestering you lol.

FFT trivial! (for any of you wondering "Fast Fourier Transform" is used to brake down a signal/complex waveform into its frequency components and provide a magnitude for each frequency band)

Trivial is not a word I associate with FFT or and I had to do them by hand so I also removed "Fast" from the FFT :-)

I think that back when I did FFT on a computer it was still not erghh fast!

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PostPosted: Sun Nov 16, 2008 11:51 am 
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Meh,


The FFT is pretty simple if you butterfly your twiddles correctly lol. We do em real time in hardware :D

Correlation and convulution is the witchcraft stuff. I've just designed a bit of hardware where you feed in a signal with more noise than correct signal and it still decodes orrectly.


As I siad last week I'd set it up for two inputs ito the ECU - one for fuelling and one for timing

It should be possible to do everything with a single DSP chip and a bit of code


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PostPosted: Mon Dec 15, 2008 9:06 pm 
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firstly a nudge for steve :-)

secondly - looking at this kit, seems it will do the job by providing a read out and more importantly having a seperate analogue output to send to ECU

http://tscsensors.com/pmdrd0000000ao0anal.html

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http://tscsensors.com/egtep0720001ssnexhau.html
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sensor is $50 and read out is $90

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 Post subject:
PostPosted: Thu Dec 10, 2009 4:11 am 
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So did you try out that EGT? Ifso, how do you like it? I have seen them on ebay lately.

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PostPosted: Thu Dec 10, 2009 4:25 pm 
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No not yet - I need a car that runs first!

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PostPosted: Thu Dec 10, 2009 10:03 pm 
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LoL. Not much to read yet I suppose. Any suggestion of what temp range I should get? Higher than 1500 degrees?
Is there any info on what EGT levels are good on a stock st205?

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PostPosted: Thu Dec 10, 2009 10:17 pm 
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IIRC it deoends on mounting location.
If you manage to actually measure real EGTs i.e. straight after valve circa 950 deg C is dangerous!

If you mount it in the downpipe then it may never get above circa 600 Deg C even when you have exceeded dangerous temps in head.

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PostPosted: Thu Dec 10, 2009 10:24 pm 
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Interesting to know. I was planning on just getting one that would place the sensor in the bung my downpipe already has for it. Will I be able to get accurate readings to if I am running rich or lean by doing this or will I need to source other options?

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PostPosted: Thu Dec 10, 2009 11:35 pm 
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I think it needs to go in either centre manifold runner for tuning. If you're just monitoring then the manifold collector seems best to me as you'll pick up on any injector going bad

The dump pipe might work for monitoring but it will be useless for tuning


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PostPosted: Thu Dec 10, 2009 11:50 pm 
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Ah ok. It won't be fore tuning. I just want to know if something goes wrong. The most I will be doing is adding a boost controller.

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