Injector Dynamic Range

[Andrew Dennison]

Peter Wales wrote:
> I replied to the question in the manner I did because I thought the
> questioner was asking a wrongly phrased question.
[chomp]
> Please
> forgive me, Mr questioner, for not calling you by name, but a computer crash
> wiped out all of my archives and I can't recall the original posting. Please
> join in! 
Ok, I will!
What my question was effectively asking was:
If you have a pulse of, say, 1.5ms what is the noise (repeatability) 
associated with this pulse?  Is it 1.5ms +/- 0.1ms, 0.01ms or 
0.001ms??
If it is 0.1ms and we have a (design) maximum pulse width of 10ms 
then the timer only needs a resolution of 100 steps (approx. 7 bit 
resolution or 42dB).
OR:
100ms pulse with 0.01 resolution: 10000 steps (14bits or 84dB).

This argument comes from normal Signal to Noise calculations, you 
could also use this to decide if you need a 10bit A/D on your MAP 
sensor or if 8 bits is enough.

Anyway, thanks Ed for your reference to the SAE paper and interesting 
discussion of injector dynamics, and thanks to all the others who 
took the time to answer.

Andrew



------------------------------------
Andrew Dennison - Research Associate
The CIM Centre
Melbourne, AUSTRALIA
Phone: +61 3 214 8296
Fax:   +61 3 214 4949
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