closed loop - s.trim chang - winter vs summer

FlashPro questions & answers specific to the FN2 European Civic Type R
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typer86
Posts: 342
Joined: Sun Oct 28, 2012 3:17 pm

closed loop - s.trim chang - winter vs summer

Post by typer86 »

Hi Hondata,
I have a general question about the S.TRIM closed loop cycle.

I have noticed in the XY graph STRIM vs AFM.c the average S.TRIM line goes in the lean section in the summer season...
Car is tuned in winter: average S.TRIM -3%
same calibration in summer: average S.TRIM +1/2%

In open loop it is compensated via IAT compensation. (If cold fuel will be added and if warm fuel will be reduced)

- Normally if warm outside the S.TRIM must also goes richer - How it works in closed loop?
- And why it is different to the open loop?
- How I could compensate this? Must I add more fuel in the IAT compensation table? I think this will be used only for the open-loop mode.

Thanks for help
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Hondata
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Re: closed loop - s.trim chang - winter vs summer

Post by Hondata »

Air temperature compensation is applied both in open and closed loop.

For Honda if they get the short term trim within +-5% they are happy, so there is not compensation for other things which vary from summer to winter (fuel temp for instance).
Hondata
typer86
Posts: 342
Joined: Sun Oct 28, 2012 3:17 pm

Re: closed loop - s.trim chang - winter vs summer

Post by typer86 »

Hmm,
I noticed if the environment is going hot incl air, the lambda values going rich... But in this case I see it is not true. Hot air contains less oxygen as cold air. Which confusing me.

It is true, If the fuel temperature is "high" in summer, the lambda values going a little bit lean?

...
OK so we can say all is fine because we are in the +- strim range.
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