[Diy_efi] injector advance

[Bevan Weiss]

The software for batch is different than for sequential.
Sequential is based on injecting when the current cylinders intake is
open... Or close to open.  It will only inject with one injector at a time
(or that's the ideal situation... Fuel demands may negate this)

Batch injection fires all injectors at once (or perhaps divides them into
sets ie 8cylinders might have two lots of 4 injectors).  These injectors are
normally fired at some uniform spacing around the rotation of the crank.
Thus batch fire doesn't require a cam sensor, but has decreased idle
quality.

At high engine speeds clearly there will be some similarities between batch
and sequential.  Sequential will begin to overlap in injection events (ie
injectors 1 and 3 will both be on for a short time together).  Hence the
advantage of sequential begins to be lost, and it starts to respond more
like a batch system.

Sequential is the preferred option never the less, simply because it's the
easiest way to meet emissions tests.  Most tests are done at idle.  Batch
will tend to have a lumpy HC emission characteristic, which most likely has
a higher average than would a sequential injections scheme.

Bevan

> -----Original Message-----
> From: diy_efi-bounces at diy-efi.org 
> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Gary
> Sent: Friday, August 06, 2004 6:59 AM
> To: A list for Do-It-Yourself EFI
> Subject: Re: [Diy_efi] injector advance
> 
> No change in software/hardware per sa, but a 'blurring' 
> effect, in regards to the precision opening/closing events of 
> the injectors, in relation to valve events.  Hope this helps 
> clarify my intent.
> 
> GAS
> 
> 
> ----- Original Message -----
> From: "Gary" <gas- at charter.net>
> To: "A list for Do-It-Yourself EFI" <diy_efi at diy-efi.org>
> Sent: Thursday, August 05, 2004 1:04 PM
> Subject: Re: [Diy_efi] injector advance
> 
> 
> > My inference of sequential becoming batch, is with the 
> > understanding, batch (or bank to bank) firing implies 
> > injecting fuel at a closed valve.  With increasing rpm, 
> > and the attending increase in fuel demand and decreasing 
> > 'window' of time available to fire the injectors, the sequential 
> > firing becomes a continued injector firing after valve is closed 
> > (or prior to opening), to meet fuel demand. 
> > 
> > GAS
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