Re: Injector opening time

[rr <RRauscher@nni.com>]

Ok, have some data. The injectors are TBI Peak-n-Holds,
# GM5235206*RPD, org/blk, 55#, 350 K van. I pulsed them
at a 100Hz rate, with a varying pulse width. P/S voltage was
held at a constant 13.8v.

I adjusted the pulse width until the injector just started to drip
fuel. I also tested at a fast drip. Pulse widths measured with a
scope. Used an LM1949 chip and TIP122 transistor drive
circuit for 4A peak, 1A hold. (Never reached peak amps
at these pulse widths).

                 10psi             18psi                30psi
Just drip:   620usec        690usec           710usec
Fast drip:  720usec        734usec           772usec

I have additional data at other voltages before I had better
control of the supply. These are interesting for comparison
purposes. (Would also be interesting to test at 24 volts).

Just drip: @ ~13.2V, 10psi: 700usec.
               @ ~13.2V?, 18psi: 772usec.
               @ ~13.1V, 30psi: 812usec.

Fast drip: @ ~13.2V, 10psi: 809usec.
               @ ~13.2V?, 18psi: 826usec.
               @ ~13.1V, 30psi: n/a

One thing about the fuel drip's, it was the repetition that
allowed for the 'just' dripping fuel. A single pulse showed
no fuel what-so-ever.

BobR.

p.s. I increased the injector bias by ~100usec as the result
of this testing. The TBI is running at 30psi.

rrauscher@nni.com wrote:

> I have some hard data for this, over various fuel
> pressures at that. Been wanting to post it, now I
> have a good reason. A tidbit from memory is that
> going from 10psi to 30psi, causes an additional
> opening delay of 100usec (~720usec total).

<snip>

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