[Diy_efi] Donegan ECU
Steven P. Donegan
donegan
Thu Jan 4 20:03:45 UTC 2007
I have not yet added OBDII to my project - it appears that I have to if
it is going to be plug compatable for my Z28 so that will likely
happen.
My intent for this project is a universal EFI/ECM/PCM/MSD box -
something useful on any engine up to 8 cylinders. If it lacks any inputs
or outputs tell me and I'll add them :-)
On Thu, 2007-01-04 at 11:53 -0700, Tom Visel wrote:
> Those OEMs that moved the regulator to the fuel tank did it for
> evaporative emissions control reasons - less heat in the tank means
> fewer vapors to deal with. This is the same batch of deep thinkers that
> brought us oxygen sensors after the catalytic converter(s) for measuring
> catalyst efficiency. If the "Donegan ECU" isn't going to be OBD-II
> compliant (or did I miss something) why bother to have the extra two
> oxygen sensor inputs? The poor OEMs only have them so they can
> guarantee to the EPA that they have a way of measuring catalyst
> degradation since all emissions systems have to be monitored.
> TomV
>
> Steven P. Donegan wrote:
>
> >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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