injection strategies for 4 cyl, port injection (1.6L Toyota

[Diehl, Jeffrey]

Ron,

The reason I would change to batch mode at higher RPM's is that it makes the
circuit easier to build.  Instead of firing the same injector twice as
often, I simple fire the same injector with both it's regular firing circuit
and another injector's firing circuit.

For example:

At idle, injector #1 is fired by circuit #1, #2 by circuit #2, etc.
In batch mode, injector #1 is fired by circuit #1 and #4, #2 by #2 and #3,
etc.

This is equivelent to firing them out of phase as you mention and will cool
the valves.

The sequential mode doesn't affect vaporization at all.  The problem is that
with large injectors, you have difficulty metering out the small amount of
fuel required for idle.  That's why OEM injectors are kinda small and run
out of capacity at high power levels.  But they idle well and pass emissions
tests at 3000RPM.  If you add larger injectors, you won't be able to squirt
out the small fuel charges in batch mode, so you switch to sequential mode..


At least that's how I understand it...

Mike Diehl,
'87 MR-2, 7age, Dual Pipes, hand-bent header.
'96 4-Runner, Bone stock.
'90 Corolla, Disguised as a Geo Prism!


> -----Original Message-----
> From: Ron Schroeder [mailto:rjs at bnl.gov]
> Sent: October 02, 2001 6:27 AM
> To: diy_efi at diy-efi.org
> Subject: RE: injection strategies for 4 cyl, port injection 
> (1.6L Toyota
> 4 AGE)
> 
> 
> At 04:29 PM 10/1/01 -0600, you wrote:
> >I've had many of the same thoughts as you seem to be having. 
>  I have a very
> >similar engine to yours.  I have a 7aGe with the ECU from a 
> 4aGe.  I've
> >looked at the schematics at great length, too.  ;^)
> >
> >One thing I thought might be cool, if you could program 
> it... would be to
> >use larger injectors and have the ECU run in sequential mode 
> at idle and up
> >to a given RPM.  Then, after that RPM range has been hit, 
> you run in batch
> >mode so that you get the valve cooling, and fuel volume that 
> you want when
> >you get nasty with this engine.
> 
> Hi Mike,
> 
> Why would you change to Batch mode at higher power RPMs, why 
> not just set
> the injector phasing to fire at the back of the valves when 
> it would give
> the maximum cooling?  I may be wrong but I would think Batch 
> firing would
> cool some valves better than others.
> 
> >The sequential mode would allow you to run bigger injectors 
> and still get a
> >nice smoothe idle which doesn't offend the nose.
> 
> Is this so vaporization is the same in all cylinders?
> 
> Thanks,
> 
> Ron Schroeder
> WD8CDH
> E. E. S.
> wd8cdh at bnl.gov
> rjs at bnl.gov
> ron at 112motors.com
> 631 344-4561 Day
> 631 286-5677 Nite
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