A new person enter's the fray.

[Mark Gagner]

Paul Rosser wrote:
> 
> I am just starting to investigate the prospect of developing a full PC
> based engine controller. I have seen the pc based one at the site and
> want to attempt a slightly different approach. I plan on using a PC
> Notebook on full time operation controlling the car through the
> parallel and serial ports. I am not to sure whether there are enough
> data line between the two but plan to find out. The reason for this
> approach is the a 2nd hand 386__ notebook with 20meg Hd and 8 meg of
> memory are selling very cheap. EG $200-300 NZ and with the addition of
> now more than $50 of parts an operational real time adjustable, Smart
> and adaptable system can be developed. The price of a Cheap After
> market system here is in excess of $1200 and that excludes ignition
> control. Some of the features I plan to incorporate are:
> 
> 1: independently pulsed injectors.
> 2: distribuless ignition.
> 3: Variable injector timing.
> 4: Boost, cam etc control options or what ever.
> 5: Security on computer (password protection). Computer can be locked
> out. Also can simply monitor battery voltages, control fuel solenoids,
> operate sirens.
> 
> The only problems I can for see are.
> 
> 1: Computer will have to run full time except on long shut downs were
> it can be switched off. It will not be hard to automate control of
> power saving features built in and also automatic power down with low
> charge battery.
> 
> 2: Possible problems isolating noise (ignition, alternator etc) due to
> electromagentic and also due to computer powered by car battery.
> 
> 3: Shocks on hardware like Hard drive etc. I don't think this will be
> a problem as shocks are of low gee's (excluding rallying).
> 
> 4: Stability. Some computers tend to just crash and other run fine for
> years non stop. This will be mainly hit and miss with the initial
> purchase of the computer. Also Programming will need to be
> bulletproof.
> 
> 5: Control lines. The parallel port only has 8 data lines. eg 4 fuel
> injector controllers and 4 ignition pulsers. Will need inputs like
> map, RPM (flywheel sensor), temp, TPS (optional), Battery voltage,
> etc.
> 
> That's about all I can think of at the moment. The project I plan to
> implement this into is either a Fiat 850 sport coupe or a Hillman imp
> 850. the motor will probably be a Suzuki swift GTI motor (1300, 16
> valve, EFI, good power and light and cheap to run, Also hopefully
> bullet proof). Other mods will hopefully be extensive.
> 
> Last of all check out my Web page. It has heaps of projects and ideas.
> 
> Paul
> 
>       __________________________________________________________
>                              Paul Rosser
>                            ThermalN Devices
>                    587 Frankley Rd Ph 64 6 7539372
>                     New Plymouth Fax 64 3 7539372
>                              New Zealand
>         Web Wheels ==> http://www.geocities.com/motorcity/3812
>       _________________________________________________________
Hi Paul,

As a software engineer with over 15 years experience developing micro
based
controls I want to caution you regarding all the data that you will need
to
get into the computer. Some of the data is not too time critical (such
as
coolant temp, air temp, etc.) but other inputs must be sensed and acted
upon
very quickly and deterministically (i.e. the time required to respond
must not
only be fast but must also be very consistent). One of the reasons that
custom
processors are generally used for controls is that we want to have
control
over all the interrupts and their relative importance... it would be
very
unhealthy for the engine if it turned out that the keyboard had a higher 
priority interrupt than the TDC sensor!

That being said, when time is more readily available than cash an older
generation PC can certainly be pressed into service. 

I suggest that you look into replacing/supplementing DOS with a
real-time
operating system. Check out uC/OS by Jean Labrosse; it was written
specifically
to run on the Intel based PCs.  ISBN: 0-13-030352-1.

uC/OS book: 29.95, uC/OS source code 24.95.
See: http://www.rdbooks.com/microcos.htm

Regards

Mark Gagner