Exhaust Temperature for tuning

[Bill Martin]

On Tue, 10 Jan 1995, A.DENNISON -EN320/TEL.8296 wrote:

> Date: Tue, 10 Jan 1995 11:54:16 EST-11
> From: A.DENNISON -EN320/TEL.8296 <ADEN at mechman.mm.swin.edu.au>
> To: DIY_EFI at coulomb.eng.ohio-state.edu
> Subject: Exhaust Temperature for tuning
> 
> I am interested in using exhaust temperature for optomising the 
> mixture - ideally for closed loop control.  I saw this mentioned in 
> the archives (which finish in May 1994 - where is the rest of it?) 
> and I was wondering if anyone has some information on what 
> temperatures to expect.
> Have you used thermocouples attached externally to the exhaust or in 
> the exhaust gas stream?  I think this idea should give more 
> information than a lambda sensor and also work for leaded and 
> unleaded petrol.
> 
> Comments anyone?
> 
> Andrew
> ------------------------------------
> Andrew Dennison - Research Associate
> The CIM Centre
> Melbourne, AUSTRALIA
> Phone: +61 3 214 8296
> Fax:   +61 3 214 4949
> WWW:   http://cim.mm.swin.edu.au/welcome.html
> 
> 

Well, acouple of comments...first, responce times for egt probes are 
kinda slow and you will always be "behind" the real-time conditions. 
Second, egt is sensitive to more than just mixture, ie. ignition advance 
and engine loading both have big effects on egt. I don't see how you will 
be able to separate the effects by measuring "just" egt. Obviously, you 
can compute/look up corrections for the other factors, but I really don't 
think the feedback loop will be fast enough to work well dynamically.

Bill Martin