[Diy_efi] Donegan ECU

[cobraman at insightbb.com]

I would like to see a PWM controller with a different purpose - say a 2 speed version - then you could use a 1000 HP pump on the street w/o beating the fuel until it boils. Run the pump, with a regulator, at say 50 lph until full throttle or boost starts, then kick it into high......  just food for thought.  TomS 

----- Original Message -----
From: "Steven P. Donegan" <donegan at donegan.org>
Date: Thursday, January 4, 2007 12:41
Subject: Re: [Diy_efi] Donegan ECU
To: diy_efi at diy-efi.org

> Well - for track days I simply put dry ice in my fuel cold-can 
> thing -
> that solves most vapor-lock style problems and lasts for a 
> couple of
> hours. Simple low-tech solution to that problem. Given the lack of
> response to my original posting I believe providing PWM fuel pump
> control and support for a fuel pressure sensor is useful. 
> 
> Given that I normally run at Willow Springs or Buttonwillow 
> during the
> winter months temps are not normally a factor anyway.
> 
> On Thu, 2007-01-04 at 12:23 -0600, cobraman at insightbb.com wrote:
> > My "Edelbrick" ProFlow has fuel pressure controlled with 
> engine vacuum. On track sessions on very hot days, the fuel in 
> the rails will boil under hard braking - accelerator closed (low 
> fuel pressure). When you finally step on it (52 psi), nothing 
> happens until the vapor "recirculates" or is expelled.  
> Usually takes a second or so.  I don't think dead heading 
> would do any better - probably just need to keep a constant fuel 
> pressure. 
> > IMHO, hot fuel should give better economy - easier to vaporize 
> - for those green members.  TomS
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > ld
> > > consume the gas in the rails well before it got warm :-) 
> However this
> > > does raise a point - perhaps my ECM/PCM/EFI computer needs a 
> way 
> > > to open
> > > a fuel return line and to sense fuel temp in the rails? Any 
> > > ideas on how
> > > useful that would be in the 'real world' anyone?
> > > 
> > > On Thu, 2007-01-04 at 14:56 +0800, Mike wrote:
> > > > Isnt one of the main needs for fuel return the fact the 
> fuel 
> > > is heated quite a
> > > > bit in the fuel rail whilst its waiting for injection ?
> > > > 
> > > > Of course there is a commercial factor as fuel returns 
> used to 
> > > be so
> > > > much cheaper than any electronics but getting around the 
> fuel 
> > > heating etc
> > > > 
> > > > Also the issue of control feedback is an issue to avoid 
> > > vapourisation> during hot start, the good thing about return 
> is 
> > > this can be flushed out,
> > > > and esp for a turbo as a pressure hold tank can "remember" 
> the last
> > > > max pressure and temporarily raise the fuel rail pressure 
> to 
> > > this during
> > > > start to avoid vapour issues... etc
> > > > 
> > > > Regards
> > > > 
> > > > Mike
> > > > 
> > > > 
> > > > 
> > > > At 07:23 AM 1/4/07, you wrote:
> > > > 
> > > > >This sounds cool...is closed loop control of fuel 
> pressure an 
> > > oem feature for any new vehicles? Or just something you are 
> > > trying out? Are you going to use a PI controller? I am 
> guessing 
> > > when you snap the throttle open the PI controller should 
> know 
> > > about this quite quickly...not wait to see a drop in fuel 
> > > pressure? 
> > > > >
> > > > >> To add something somewhat useful to the list in this 
> reply 
> > > I'll say the
> > > > >> Donegan ECM is coming along nicely :-) The input board 
> is 
> > > going to fab
> > > > >> out at about 3.0 inches by 2.2 inches (exactly matching 
> the 
> > > CPU board -
> > > > >> ARM based Steve). Inputs designed in are MAP, MAT, 
> > > Barometric, Coolant,
> > > > >> Throttle, Oil pressure/temp, 4 ea O2 sensors, Crank and 
> Cam 
> > > position, 2
> > > > >> ea EGT sensors - well pretty much everything everyone 
> told 
> > > me should be
> > > > >> sensor inputs. Fuel pressure input I'll put on the 
> 'relay' 
> > > control board
> > > > >> - that will do PWM control of the fuel pump eliminating 
> the 
> > > need for a
> > > > >> regulator or return line.
> > > > >> 
> > > > >> Happy New Year :-)
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