Injector timing qns.

[Jonathan R. Lusky]

Craig Pugsley writes:
> 
> i/  Does the timing of the injector relative to the timing of
>     the intake opening matter much?. IE if you've got the same
>     injector on time, but change the 'phase angle' relative to the
>     cam, will the power output vary much?
 
At lower injector pulse widths it can make a noticeably difference
in fuel consumption and emissions.  At higher pulsewidths it
doesn't have any impact.

>     Rewording, will power output change much between full sequential
>     and simultaneous injection, if you assume (as with L-Jetronic)
>     that the fuel can "Hang around" in the intake while the valve
>     is shut, or for optimum power should the fuel injector only be
>     turned on while air is flowing into the engine?

At WOT sequential injection is worthless IMHO.  Your injectors will
be spending considerably more time open than the intake valves.
 
> ii/ Does anyone have a graph of fuel flow/minute vs injector duty
>     cycle at high RPM. (Concerning injector opening&closing times)

This is going to be a function of fuel pressure and different for
every model of injector.
 
> I'm in the process of building a basic analog injection computer so I
> can get a feel for how the fuel algorithms work, then put it into a more
> elegant microcontroller form (Probably 8051 based)

Doesn't sound particulary useful to me...  I think it'd be much more
useful to put together a good little data logging system and then sample
an OEM system in action.

-- 
Jonathan R. Lusky                       lusky at knuth.mtsu.edu
http://www.edge.net/erc/lusky.html      (615) 455-9915
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