[Diy_efi] Donegan ECU

[Mike]

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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