[Diy_efi] sequential injection timing

[Bruce]

----- Original Message -----
From: "Mark Claywell" <clay0052 at umn.edu>
Subject: Re: [Diy_efi] sequential injection timing
> > > It might be that injecting onto the back of the hot intake valve helps
> > > vaporization.
> > Yes, but the primary action to get the fuel *burnable* is the exhaust,
at
> > overlap that atomizes the fuel.
> I would have to disagree with that, as would I think most fuel injector
> engineers. There has been a large push by Deplhi and Siemens among others
> to work on injectors with a bent spray (or gamma angle) to allow proper
> targeting of the injector spray. Proper targeting is a large portion of
> getting good mixture preparation.

Disagree all you want, but that doesn't change what's going on.

> > >I think that the injection timing really only matters for
> > > idle and part throttle,
> > Yes.

> Injection timing is important for emissions, cold start, throttle
response,
> and making MBT (max. brake torque).

Only if you're worring about CAFE, and the EPA.  In the real world it aint
no big thing, feel free to review the archives.

> > >since under moderate to heavy load the injector
> > > would be open more than closed -- to the limit that under WOT it would
> > > be mostly open all the time anyway (say 70-90% duty cycle) so it
> > > wouldn't really matter much.
> > True.

> If you can decrease injection time for the same amount of mass injected
> without letting SMD suffer, injection timing can become more important,
> even at high load/rpm sites.

Swing by some time, and in back to back tests I can show you the difference.

> > With really large injectors, there is at times much to be gained with a
> > single batch fire system.  Firing the injectors twice as often helps
with
> > atomization.  My little 3.8L with 55#/hr injectors is much sweeter in
> batch mode then SEFI.

> Is this under transient or steady state conditions? SMD usually suffers at
> close and open of the injector, but I have heard of improvements in
> transient fueling with multiple injections per cycle on some setups.

In all areas.
And no hearing about, guessing, or maybes.
Bruce
>
> mark
>
>
>
>
> > Bruce
> >
> > > Brian
> >
> >
> > _______________________________________________
> > Diy_efi mailing list
> > Diy_efi at diy-efi.org
> > http://www.diy-efi.org/mailman/listinfo/diy_efi
> >
>
>
>
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://www.diy-efi.org/mailman/listinfo/diy_efi


_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi