Injector Driver Module

[Jose Rodriguez]

Don, thanks for your reply.

  I am going to fire them sequentially, like you indicate below. Yes, I also see that the factory heatsinks on the driver transistors are not big, and that is what surprises me.
  The only explanation I have so far is that the injectors used by the OEM modules are the saturated type (16 ohms, and the driver is not working on the linear region, but saturated, and hence very little power is dissipated there). Unfortunately, I need to drive peak-and-hold injectors (1.5..2.3 ohms).
  Over the 360 crank degrees, the injectors will be fired approximately like this:
#1 (0 degrees), #8 (45 deg), #4 (90), #3 (135), #6 (180), #5 (225), #7 (270), #2 (315).

  Every driver would be on up to 85% of the time, so no matter what the timing sequence is, every power driver will conduct the Hold current (1 amp) for 85% of the time, so the average power dissipated on the driver module box is:
  [ (Battery Voltage)-(Hold Current)*(Coil Resistance) ]*(Hold Current)*(Duty Cycle)*(number of injectors) =
  so assuming worst case (Maximum battery voltage):
  [ (16)-(1)*(1.5) ]*(1)*(0.85)*(8) = 98.6W!

  How much power is being dissipated in your module?

>>> <Don.F.Broadus at ucm.com> 08/10/98 10:47AM >>>
I'm working on an  injector driving module also. If you are going to fire
the injectors sequentially, then one injector would be on at a time in the
firing order sequence (1-8-4-3-6-5-7-2 GM V-8)  If you are going to batch
<snip>