> -----Original Message-----
> From: Impakt242@AOL.COM [SMTP:Impakt242@AOL.COM]
> Sent: Friday, November 01, 2002 11:31 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: [PIC]: Getting signal safely from fuel injector
>
> In a message dated 1/11/2002 10:29:00 PM AUS Eastern Daylight Time,
> mrjones@NORTELNETWORKS.COM writes:
>
>
> > Sounds like an interesting project, I was considering something simmilar
> to
> > measure fuel economy, integrating the injector open time to get amount
> of
> > fuel used and using the speed sensor to get distance covered.  Not sure
> how
> > accurate this would be though.
> >
> > Regards
> >
> > Mike
>
> hmm to get a decent result you would need to know the fuel pressure at
> given
> loads and throttle positions. I'll try it all out once i get the pic next
> week with all the testbed gear as well :)
>
> Anyone else have any ideas?
>
> Daren
>
Fuel pressure accross the injectors should remain the same at all throttle
openings, that's why there is a fuel pressure regulator controlled by
manifold pressure. :o)  The major non-linearity (AFAICT) is during the
opening and closing times of the injector, which is significant for very low
and very high duty cycles.

Other ideas?  Hmm, you could use a hall effect sensor which would mean you
wouldn't even have to make an electrical connection.  Come to that you could
use inductive coupling as you are only interested in the egdes.
Opto-isolators are cheap, do you have anything in particular against them?

Mike

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