simple analog fuel injection

[Sandy]

Just get a simple PIC and be done with it. Not that hard to program, and
will be a better controller then a bunch of 555's. 

Warning, the above represents 2 cents, use at your own risk. ;-)

Sandy

At 10:00 PM 6/22/98 -0400, you wrote:
>
>-----Original Message-----
>From: Ron Tyler <dcmckenna at worldnet.att.net>
>Subject: Re: simple analog fuel injection
>
>
>  You will need to have a gain and an offset pot.
>>> The gain sets the slope of the pulse-width versus MAP, and the offset
>>> pot shifts the whole curve (or rather, straight line) up and down the y
>axis.  You can even use the offset pot as a manual 'choke' equivalent.
>>> The system won't be as good as a real modern EFI, but I have found that
>>> on a small tuned 4 cylinder engine (998cc Hillman Imp) it works better
>>> than the old twin 1.25 carbs ever did. (I only suggest you try this on
>>> vehicles that aren't subjected to stringent emissions checks.
>>>
>>  Chris,
>>         I'm not a hack, but I am familier with the 555. I believe I
>>understand the concept, but I dont know how to build in "gain" for the
>>MAP. Can you send me a schematic or mabey a brief verbal summary please?
>>Also, how would you build in an "accellerator pump" with a TPS?
>>Mucho Thanx
>>Ron & Stephanie Tyler
>
>
>%TPS change per amount of time.  Or change of voltage per amount of time.
>Remember you have 70% throttle opening at 20% throttle
>travel.  Then cold coolant correction.  Air temp correction.  RPM
>Correction, gee gettin complex quick.  I'm not at all trying to rain
>on your parade.  Within the last 6-7 months I think this very issue
>accleration pump has been talked about.  Think the final thoughts were 5
>tables, corrections for it.
>  You can minimize these corrections IMHO by using a fuel pressure
>regulator referenced to engine vac.  But, still complex, to do right.
>Also, intake tract ducting can help (ie real long in lenght).
>  If I had to do something along these lines I rack a bunch of 555's
>together.  Base Pulse width, then temp correction, then air correction
>accleration/TPS, accleration temp, accleration MAP etc etc.  add'em
>up and then fire the injector(s).
>Just some thoughts
>Bruce     One similiar project here at CSH, HQ was a traction
>               control device worked really nice then one night temp
>               dropped on test drive a couple degrees, and the car
>               could not be made to move, disable TCD and drove
>               home.  Put device in freezer wouldn't work.  Thaw to
>               34+ and it was fine.  Could not be made not temp
>               sensitive.  Months of work down the drain...  Tandy
>               Corp stock rose $2/share over what I spent at radio
>               shack
>