Re: Ford injectors (& Question)

["Dave Zug" <dzug@delanet.com>]

Thanks Roger.. I see my mistake.  Much thanks.

----- Original Message -----
From: Roger Heflin <rah@horizon.hit.net>
To: <gmecm@diy-efi.org>
Sent: Friday, August 18, 2000 3:50 PM
Subject: Re: Ford injectors (& Question)


>
>
> On Fri, 18 Aug 2000, Dave Zug. wrote:
>
> >
> > So if I have this right, Let me write this in other terms...
> >
> > Lets say for example a car cruising is doing 5 ms pulses at a constant
6000
> > rpm (for math's sake).
> >
> > Its pulsing like this:
> >
> > each bit is 0.5 ms: (2 crank revs = 1 cam rev =20 bits). 20 ms time is
> > represented (4 engine "strokes").
> >
> > 1111100000 1111100000 1111100000 1111100000 Left
> > 0000011111 0000011111 0000011111 0000011111 Right
> > <----------10 ms--------> <---------10 ms--------->
> >
> > Alternating left and right for HALF the PW time each 10 ms to complete
the
> > full PW time within one CAM rev.
> >
> > Then we go to WOT and for math's sake lets say we gain no RPM's or
fueling
> > requirements.
> >
> > Its pulsing like this:
> >
> > each bit is 0.5 ms:
> >
> > 1111100000 1111100000 1111100000 1111100000 Left
> > 1111100000 1111100000 1111100000 1111100000 Right
> > <----------10 ms--------> <---------10 ms--------->
> >
> > Now to the (almost) REAL world.. Heres what WOT looks like (constant 9
ms
> > requirement) :
> >
> > each bit is 0.5 ms:
> >
> > 1111111110 1111111110 1111111110 1111111110 Left
> > 1111111110 1111111110 1111111110 1111111110 Right
> > <----------10 ms--------> <---------10 ms--------->
> >
> > The above example has the injectors on IN UNISON for a total of (0.5 ms
*
> > 18) or 9 ms over each 10 ms (1/2 valvetrain cycle) period. the listed PW
> > then repeats itself for the next 10 ms with no recalculation taking
place
> > (??) to complete the valvetrain cycle.
> >
> >
> > Do I have it right?
>
> Close, I believe they actually pulse the given pulsewidth at once, so
> when the computer says 9ms it actually opens it for 9ms, and then
> closes for 1ms, not (4.5ms, close .5, 4.5, close .5)   On the
> sequential cars it would list 9ms as 18 ms, and keep it open for I
> believe the entire time or almost the entire cam rotation.    I don't
> know if they alternate banks, I would need to look at the code to
> figure out that and how exactly it compares to the actual cylinder
> timing.  My guess is that it may not really even match up consistantly
> with the cylinder timing, just close enough, I suspect also since the
> injectors have difficulties with being closed for short periods of
> time that that may be the reason to not even try to time single
> cylinder events, since this would required bigger injectors to avoid
> getting the close time too low.
>
> Roger
>
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