Simple Injection Questions

[Gary Derian]

I think a single cylinder engine will have a very discontinuous air flow
which effectively eliminates MAP and MAF.  The simplest system I can think
of is alpha-n, rpm and throttle position.  It can be mapped to a lookup
table and then corrected for temperature and exhaust O2.  But why do you
insist on closed loop?  As far as I know, that is most useful for making a 3
way cat work.  Without a cat, you actually want a lean cruise and rich PE.
Neither of which are well indicated with a normal O2 sensor.

To answer your second question, no, you don't need to include ignition
timing although there are advantages associated with electronic spark
timing.

Gary Derian <gderian at oh.verio.com>


> Hi, I've been lurking for a little while and have a couple of questions.
> It seems this list is very detail oriented, my questions are more
specific.
>
> I would like to know how to make a very simple injection system, possibly
the
> simplest
> available design, with the caveat that it must be closed loop, and have
> reasonably good
> performance.  My current plan revolves around a 68HC11 or '332 with an O2
> sensor.  This will be targeted at a 650cc single cylinder motorcycle
engine.  I
> assume I will also need a tach sensor, throttle position sensor, and some
kind
> of manifold sensor.  What is the minimum subset of sensors that you need?
What
> kind of manifold sensors exist?
>
> Do I have to take over ignition as well?  What's the cost/benefit of this
> integration?  I already know that this particular engine lacks a rev
limiter so
> I'd want to incorporate that feature.
>
> It seems the list focuses mostly on control systems.  I'm wondering where
to buy
> things in small quantities like throttle bodies with TPS, mass flow
sensors,
> pumps regulators, injectors.  In short, all the goodies I don't already
have (
> computer guy if you hadn't guessed).
> Thanks folks!
> Beez
>