Air Flow Measurement

kleenair at ix.netcom.com kleenair at ix.netcom.com
Tue Nov 19 18:38:15 GMT 1996


> 
> 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?????
> 
> Tom Cloud <cloud at peaches.ph.utexas.edu>

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).
By the way, don't ask me what the SAE paper number was, cause I don't have it and I can't remember. Mmmmm I'm 
starting to sound like a politician!



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