Asynch vs Synch Injection

[Jeff M]

This helps me too and confirms as I just finished up successfully doing the
AE changes for some bigger injectors in a friends car.  It makes sense and
McGraw-Hill Tech Dictionary says it as well "Asynchronous Control: a method
of control which the time allotted for performing an operation depends on
the time actually required for the operation, rather than on a predetermined
fraction of a fixed machine cycle (engine rpms)"

Jeff M


>
>
> "Dave Zug." wrote:
> >
> > Sync is "clocked"
> > Async is not clocked.
>
> Yup, but.....
>
> >
> > If I make a feeble attempt to translate this...
> >
> > Sync is USING the o2 as feedback,
> > Async is NOT using the o2.
>
> Nope.  Sync means that the injector firing is synchronous to the
> crank/cam position.  ie it happens at a particular time that is related
> to the crank or cam position.  Async means that the injector fires at a
> time that is not related to the crank or cam, a time that the ECM picked
> "just because".
>
> > > Async, is for high fuel demands when you needs lots of fuel, ie Heavy
AE,
> > > WOT.
> > > Sync is for like idle, and cruise
> > > Grumpy
> > >
> > >
> > > > Does anyone have a good understanding of the differences/relations
> > between
> > > > asynchronous and synchronous Injection.  About all I've figured out
so
> > far
> > > > is that it's counter-intuitive (in asynch they fire at the same
time).
>
> Maybe you're asking about sequential versus batch?  For port injected
> systems injectors can be fired in groups (batch) or each at their own
> individual time depending on the position of its piston (sequential).
> Either way is synchronous, in that injector firing is done by the ECM in
> response to the crank/cam position (SYNChronized to the engine).  If the
> ECM wanted to add an extra fuel pulse, like Bruce said for AE or WOT,
> then it would be asynchronous.
>
> --steve
>
>
> --
> Steve Ravet
> steve.ravet at arm.com
> ARM,Inc.
> www.arm.com
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