Re: Asynch vs Synch Injection

[steve ravet <sravet@arm.com>]

"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@arm.com
ARM,Inc.
www.arm.com
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