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Re: Asynch vs Synch Injection



I believe that is quasi-asynchronous mode.

Jim Sloan
leroy@sunflower.com

----- Original Message -----
From: "Jeffrey Scott" <jws6367@mailcity.com>
To: <gmecm@diy-efi.org>
Sent: Thursday, April 20, 2000 3:24 PM
Subject: Re: Asynch vs Synch Injection


> Just to add some confusion, back when I was studing the P4 doc.  I thought
that sync/async refered to how the computer triggered the injectors.
Because at idle with the small PW the spray pattern was not great, it went
into another mode that would skip each cycle, but when it did fire would
spray twice as much.
>
> Maybe I studied the doc too much, not enough, or got the pages out of
order..
> ---
> Jeffrey Scott
> JWS6367@mailcity.com
> NWSTP founding member (1of2)
> ICQ #25436277
> 92 ty#1295  black/black
> 67 Camaro
> 63 Nova
> http://www.geocities.com/baja/dunes/9423
> nwstp.syty.org
>
>
>
>
>
>
> On Thu, 20 Apr 2000 14:57:33   steve ravet wrote:
> >
> >
> >"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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