O2 feedback

Bruce Plecan nacelp at bright.net
Thu Jun 18 15:39:14 GMT 1998


-----Original Message-----
From: Martin Hill <EAXMJHI at ean2.mecheng.nottingham.ac.uk>
Subject: Re: O2 feedback


It might enable you to run a leaner AFR, but the introduction of EGR
does not change the actual AFR present, you still have the same
amount of fuel going in, and the same amount of air going in.
Therefore AFR is the same.


Nope, EGR can displace up to 10+% of the incoming air.  That changes MAP/MAF
signals, changes where the ecm is looking in
the tables.  You have less O2 in the EGR, also.
Again, also applies fuel timing corrections.  These corrections help to
make the transistion invisible to the driver, and lower emissions.
  Ecms can be a lot more sophisticated then ya give them credit for.
Remember the the posting about 70+ tables on a 747, or that on a
low code 808, there are 282 tables/switches.....

Cheers
Bruce

Martin



> > But there shouldn't be a change in AFR when you apply EGR.
> Doesn't EGR allow you to run a leaner AFR (someone had told me that a
> while ago)?





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