There's a number of tables in the LS4 that refer to Intake Valve Temperature - specifically in several of the Transient Fueling tables.
Can anyone comment on how the ECM is calculating the Intake Valve Temperature value?
Thanks
:cheers:
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There's a number of tables in the LS4 that refer to Intake Valve Temperature - specifically in several of the Transient Fueling tables.
Can anyone comment on how the ECM is calculating the Intake Valve Temperature value?
Thanks
:cheers:
The IVT and Injector Tip Temp values reported seem to be VERY low on the logs I have.
it's a mathematical model that uses ECT, MAP, RPM, spark, afr and also alcohol mix.
I figured it was something like that, maybe even including factors for the effect of fuel boiling off the back of the valve. Any chance that you can share the model with those of us who don't look inside ECM's? :pray: :worship:Quote:
Originally Posted by Chris@HPTuners
:cheers:
its a linear model with coefficients that are obtained by experiment i guess. not something you could easily "tune"
IVT = a.X + b.Y + c.Z + etc...
Thanks Chris, this helps
Just trying to gain an understanding of how GM determined a value that can't really be measured in a vehicle, but drives things that I can tune.
A linear function you say.......time to dust off the regression analysis text and see if I can come up with an approximation.
:cheers:
Here's a test - this is only a test:
Put the car in Open Loop.
Take your IVT values starting at 1.0 at your current outdoor temperature for the day and add .01 to them (with all other O/L AFR modifiers set to 1.0) in increments vs IVT temperature. Now monitor Commanded AFR and IVT and see how well they match. :D
For those who may be interested, I came across a SAE Technical paper today that discusses IVT modeling and transient fuel compensation in some depth. I expect that it will take a while to digest the info contained in the document.
Here's the link for anyone who is interested
**Warning Math Content**
http://delphi.com/pdf/techpapers/1999-01-0553.PDF
:cheers:
Anyone have a copyof this PDF?Quote:
Originally Posted by TiredGXP
Nice find.