Air Flow Measurement

[Thor Johnson]

On Tue, 19 Nov 1996 kleenair at ix.netcom.com wrote:

> > 
> > My long-standing question -- precisely ...... 'cept I think I've
> > one-upped you (?? tell me what's wrong with this concept ??).
> > 
> > If you know BAP and MAP, you know delta-P across opening -- granted,
> > the opening size varies with throttle position, but you've got TPS
> > for that -- seems that air flow could be rather accurately determined
> > without much hassle?????
> 
> This method actually works pretty good.  In fact, for throttle body injected applications, it is theoredically 
> better than a MAP sensor measurement for transient fueling reasons.  But neither the MAP / RPM / IAT (speed 
> density) nor TPS / RPM / IAT method are as accurate in measuring air flow as a mass air flow system.  I have 
> read an SAE paper on using TPS for air flow, although the purpose of the paper was to improve on transient 
> fueling calculations currently used.  The only problem with applying this to a stock fuel injected car is of 
> course the IAC motor which bypasses the throttle blades (in most cases).


What's wrong with speed-density?  And what exactly do you do to it?  I 
thought it was just found by Air=K*MAP*RPM (where K is a magic constant), 
but I'm naive.  Am I going to get into trouble using this?

                Thor Johnson
       johnsont at falcon.mercer.peachnet.edu
   http://falcon.mercer.peachnet.edu/~johnsont
                                                    
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