Turbo speed sensor ever used ?

[Mike (Perth, WA)]

At 08:39 PM 6/03/2000 +0100, you wrote:
>Hi!
>I think its very strange that any form of turbocharger rpm or measuring
>backpressure in a turbo application is not more used in cars.

Yes wondered that a little, though thought (so far) the use would be
negligible, assuming correct operation (and B/w) of other sensors,

>A changing backpressure ,depending on the rpm on turbocharger and wastgate,
>has a great influence on cylinder filling .A map sensor is not aware of
>whats going on , and air volume measuring is missing the right ignition
>timing.
>Boost VS.backpressure is great to know in development stages.Tells the
>efficency
>of the turbo used.
>Spool up creates more backpressure ,more backpressure ,wants less ignition
>advance.
>less air consumption .A fast car is living in theese arias all the time .

mmm - Interesting, I'd assumed air flow measurement and MAP would be
sufficient to determine volume of air entering the chamber. Are you
suggesting AFM doesn't give an accurate enough figure due to backpressure
at the turbo and that MAP in no way assists this - in the circumstance
where we have an AFM and MAP ?

Should we have a pressure sensor before and after turbo or just one, surely
AFM output would indicate chamber volume as the air can't go anywhere else ?

>Just some toughts

Yeah sure, what-ever arrives at an improved understanding, tah,

I've alwayus wondered what the relationshiup is between boost and less
ignition advance - is it simply chamber filling, propensity to ping, or
some other presumably non-linear relationship ?

<mmm> even more to think about and "algorithmate" - somewhere,




Rgds ~`:o)

Mike Massen         Trading as "Network Power Systems" and "Network Computers"
Perth, Western Australia  Ph +61 8 9444 8961  Fx +618 9264 8229 (fax -> email)
Products/Personal/Client web area at http://www.wantree.com.au/~erazmus
 (Current pics - trip to Malaysia to install equipment in jungle power site)

Some say there is no magic but, all things begin with thought then it becomes
academic, then some poor slob works out a practical way to implement all that
theory, this is called Engineering - for most people another form of magic.

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