Injector control question

[Tom Cloud]

In examining my Holley ProJection (model 502 analog) I find
that the pulse width to the injectors is a constant (approximate)
1 millisecond with the rep rate varying by RPM, TPS and (maybe)
temp.

I'm sure this question has been answered in various ways
before, but it's popped to the fore for me and I'd like to
hear some of your thoughts on it ...

Seems to me there's two ways to control an injector ..

 1 - run a constant rep rate (PRR) and vary the pulse width (PW)

 2 - run a constant PW and vary the PRR

 3 - all of the above  ;-)  (I know, I said two ...    8-)

Insert comments here (please) ......


NEXT ...

   Some time back (few weeks ago) there was a question
about building a meter to monitor the PW of injectors
and I replied that this was just a tachometer -- i.e.
a duty cycle monitor -- where 100% would make the meter
go full scale (or to "100" on a DPM) -- this should
track duty cycle rather nicely -- as long as the rep
rate doesn't fall so low the meter starts "bouncing".

But then, someone pointed out that I was a dunce and
that duty cycle and pulse width were different animicules
(and he is certainly right -- on both counts  ;-)

Now, the question  .....  why do you (whoever you are) want
to know pulse width when fuel delivery is predicated on
duty cycle (i.e. pulse width vs. rep rate) ????

Measuring the pulse width is do-able, but certainly
more complicated that putting your VOM on the injector
line and marking the 12 volt mark as 100% (I know, I
know, it's slightly more tedious than that -- put a
single transistor saturated switch in to condition the
injector pulse to a 0-12 volt swing and **then** do it!!).

  ++++++++++++++

well, that was kinda two questions .... I guess  8^)

Tom Cloud

        Ever stop to think .... and forget to start again ??