[Diy_efi] Donegan ECU

[Steven P. Donegan]

I had not thought of fuel temp at all - every vehicle I drive would
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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