The degreeing isn't quite that precise, but close. Early injection occurs only when the engine is either hot enough or rpm is high enough that puddling doesn't have time to occur and is done primarily to give the fuel mist the maximum amount of time to vaporize. That produces the maximum fuel usage efficiency and the least misfire and HC emissions. Late injection is done at other times when puddling is the more significant risk. ----- Original Message ----- From: Frank Devocht To: [email protected] Sent: Sunday, June 20, 2010 2:43 PM Subject: Re: sequential fuel
Must do homework. Did some more reading and managed to clear a couple of things up. Do I understand correctly that early injection would mean starting the pulse at 49° ABDC = 131° BTDC, right when the valve has closed? Likewise, late injection would mean starting the pulse at about +360° BTDC, a bit after it started opening (at 8° BTDC)? Frank From: Frank Devocht Sent: Sunday, June 20, 2010 10:51 PM To: [email protected] Subject: Re: sequential fuel Digging up an old thread here, now that I've started looking at this again. There's a couple things I don't understand.t "Early injection starts as soon as the intake valve closes", doesn't this mean you're firing onto a closed intake valve, making a puddle? The intake valve closes at 49° ABDC (that's 229°, right?). Wouldn't one want to end the injection puls right before the valve closes, instead of starting it on a closed valve? "late injection starts after the TDC when the intake valve has already started to open". The 99 intake opens at 8° BTDC, so you're injecting at a couple degrees ATDC? Currently my settings are such that when cranking, my pulse ends at 2° and when running at 229°. Does this make sense? Frank Auteur: Ray Ayala Datum: 2009-11-12 15:372009-11-12 14:37 +100UTC Aan: Eric Schieb, miatapower Onderwerp: Re: sequential fuel In my previous post I meant to say that late injection is used (when appropriate) to prevent the fuel from sticking to the manifold walls, not the cylinder walls ... as well as to prevent puddling on top of a closed intake valve. IMHO puddling is a major factor in low-rpm misfire for a multitude of reasons. Early injection starts as soon as the intake valve closes while late injection (used only when the angular-duration of the injection pulses is less than 90 deg) starts after the TDC when the intake valve has already started to open and air has started moving in the manifold runner. ----- Original Message ----- From: Eric Schieb To: miatapo...@??? Sent: Wednesday, November 11, 2009 7:27 PM Subject: Re: sequential fuel Ray, Can you relate "late as possible"and "early as possible" to engine events? I don't do much cold engine work considering most of my work is on race cars. If it is too cold, they don't come out of the trailer. However, for a warm engine, we are typically firing our idle pulses slightly before the intake valve open event and our wide open throttle pulses are ending before the intake valve close event. I know for a while it was Ford corporate policy to not fire on an open intake valve due to bore wash concerns. Eric Schieb Ray Ayala wrote: > During cold cranking & idle the newest Link chips inject as late as possible to provide as little time as possible for the fuel droplets to land on and stick to cold cylinder walls. At other times it injects as early as possible to allow maximum time for vaporization before firing. > ----- Original Message ----- > From: Frank Devocht > To: miatapo...@??? > Sent: Wednesday, November 11, 2009 12:47 PM > Subject: sequential fuel > > > How exactly is seq fuel set up on the Link (or any other ECU) ? > Does it always inject at the same point in the cycle (where is that?) or does it use a rpm/load dependent lookup table ? > Is there a differnent point when cranking / running? (I remember that my Link used to start insanely fast when switching to the chip with sequential fuel) > > > Frank > > > ------------------------------------------------------------------------------ > > > _______________________________________________ > Miatapower mailing list > miatapo...@??? > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > > > ------------------------------------------------------------------------ > > _______________________________________________ > Miatapower mailing list > miatapo...@??? > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > _______________________________________________ Miatapower mailing list miatapo...@??? http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower ------------------------------------------------------------------------------ _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower ------------------------------------------------------------------------------ _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
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