[Fwd: High-impedance injector off a low-impedance driver?]

[Don Sauman]

Additional to my previous email..

You could, and this is common, use a Darlington Pair transistor driver or you
could use MOSFETs or IGBTs (Insulated Gate Bipolar Transistors).

A good choice might be the IRZ44NS/L logic level power MOSFET made be
International Rectifier.

Hope that helps.

Cheers
Don

Don Sauman wrote:

> Hi from a new person to the list.
>
> Things to consider:
> Op amps normally require +ve and -ve rails
> Slew rate 1.e. how fast the out tracks input may be a problem at some revs
>
> Otherwise impedance conversion a good idea but look for a single rail device
> like a transistor configure as an emitter follower.
>
> Cheers
> Don
>
> "Geddes, Brian J" wrote:
>
> > Okay, after a little research and lots of good advice from Bruce of the
> > Megasquirt site, I've figured out that I can't run the two injector types in
> > parallel.
> >
> > An EE friend of mine had the following idea:  what if I got an opamp, set it
> > to a gain of 1 (I think that makes it a voltage follower?), and wired the
> > inputs of the opamp in parallel with my low-impedance injector?  I could
> > then use the opamp's output to drive the high impedance injector.  It seems
> > like that should effectively recreate the ECU's injector driver signal for
> > my additional high-impedance injector, but have it draw it's current
> > directly from the battery/alternator.
> >
> > I'm no EE though.  Any problems with a system like this?  And where would I
> > buy an opamp?
> >
> > Thanks,
> > - Brian
> >
> > > -----Original Message-----
> > > From: Geddes, Brian J [mailto:brian.j.geddes at intel.com]
> > > Sent: Wednesday, March 06, 2002 10:25 AM
> > > To: DIY EFI Mailing List (E-mail)
> > > Subject: High-impedance injector off a low-impedance driver?
> > >
> > >
> > > All -
> > >
> > > Hello!  I'm new to this list - I just stumbled across it
> > > yesterday while
> > > doing some research on fuel injectors.  As a newbie, of
> > > course, I have a
> > > question.  :)
> > >
> > > Is it possible to run a high-impedance (saturated) fuel injector off a
> > > low-impedance (peak-and-hold) driver?  I have high-impedance
> > > injectors in my
> > > car (a '94 turbo mitsubishi), and would like to run a additional
> > > high-impedance injector in parallel with one of my stock low-impedance
> > > injectors.  What I've seen so far in my research makes me think it's
> > > possible, but I'm not quite sure enough yet to try it.  Has
> > > anyone done
> > > something like this?  Would I need to stick a resistor in before the
> > > high-impedance injector?
> > >
> > > Thanks,
> > > - Brian Geddes
> > >
> > >
> > >
> > > ----- End of forwarded message from owner-diy_efi at diy-efi.org -----
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> >
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>
> --
> Don Sauman
> Perth, Western Australia
> "Life is short, live it now."

--
Don Sauman
Perth, Western Australia
"Life is short, live it now."


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