[Diy_efi] Donegan ECU

Fri Jan 5 18:40:53 UTC 2007

By it's very nature a PWM based controller is already N speed - ie
whatever you want. And the MOSFET's I have chosen for my design do like
70 amps worth of switching so  should be able to sleep (ie pretty much
not need heat sinks) through injector or fuel pump control chores...

On Fri, 2007-01-05 at 12:26 -0600, cobraman at insightbb.com wrote:
> 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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