Injector Driver Module

[Jose Rodriguez]

 Thanks for your response, Greg.

  I have looked at the EFI332 design, but I have not been able to find any info on the injector driver's design other that they use National's injector driver IC, and some other electronic parts.
  That does not help me a lot, since the power dissipation on the injector driver, using a peak and hold driver, is not dependant upon the driver IC itself, but on the system voltage, the hold current, duty cycle, and the injector coil's resistance.

  There are mainly two types of injector coils: the saturated and the peak-and-hold ones.
  The saturated coils typically have 16 ohms resistance and yes, if I used them the power dissipation would be greatly reduced on the injector driver side, specially since I could saturate my drivers, so the power would be negligible.

  If most OEM coils are saturated, that would explain why they can do it with such small heatsinks. I wish I could put the module in the interior, but that is not an option.

  Unfortunately, I am currently being forced to use the peak and hold coils (1.5..2.3 ohms), because the injectors are to deliver a very high mass flow, and work over -40..125C. I am told the saturated coils can not reliably work under those conditions.

  The prototype schedule, as you might have guessed, is for Yesterday. :-(

>>> "Gregory A. Parmer" <gparmer at acesag.auburn.edu> 08/10/98 09:46AM >>>

On Thu, 6 Aug 1998, Jose  Rodriguez wrote:
>   I am designing an injector driver module.

If you haven't do so already, you should compare
your design to the EFI332 one at
http://efi332.eng.ohio-state.edu/efi332/hardware.html 


>   Injector coil resistance: 1.5 ohms (it could also be 2.3 ohms)
<snip...>
>   If all 8 injectors could be on 85% of the time, then the maximum 
<snip...>

A few more quick thoughts. GENE already pointed out that for a 4cycle
engine you're talking about half of 85%. Also, I think most
OEM port injectors have a higher resistance (15+ ohms?).
This makes your power consumption figures look **much** better.
Also, mounting your module in the car interior as most OEMs
do helps your underhood heat problem.

When's the prototype scheduled?   :)
-greg