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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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