GM ECM injector driver capacity

Sandy sganz at wgn.net
Tue Aug 25 17:06:39 GMT 1998


I don't know about the nubers, but it relates to the heat dissipation of
the flyback diode. Look at the LM1949 datasheet, it has some rough
calculations for power dissipation of that. Like I said, might be fine, but
you now have 9 times the current going back into that diode, and although
the numbers seem low, I would imagine that it will more 9 times more heat
as you are dumping much more back emf them one injector. The real question
is, since they were peak and hold, and the impedance of the injector is
much lower, thus drawing lots more current the EMF from that type of
injector will be much higher, how much, I doubt 9 times, but might just
work fine. The bigger problem _again_ is that if the injector is a peak and
hold type, and it goes into hold mode will you be driving 10 injectors with
1/4 of their required current. 10 saturated injectors = 10 amps in parallel. 

Anyone that knows electronics jump in at any time ;-)

Sandy

At 12:03 PM 8/25/98 -0400, you wrote:
>OK, I have one injector, and it is perfectly designed, and does the
>following
>
>14.2 ohms
>runs on 14.2 v
>draws 1 A
>
>when turned off generates
>300v
>.001A
>.001msec.
>
>When I hook up 9 more, wouldn't I expect to see, at turn off
>300v
>.01A
>.001msec
>
>Why would more produce more voltage rather than current,
>or anything more than more current?.
>TIA
>Bruce
> 



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