555 EFI again...

[Webb Family]

Sorry to but in here, but an off the wall idea just occurred to me.

You were talking earlier about how hard an analog multiplier is to come up
with. At the same time, you are worried about this "unwanted" logarithmic
charge characteristic.

If you set up the 555 so that the time between sparks is the cap charge time,
cap discharge time is the on time for the injector, and the tps controls the
CAP charge voltage, is that not the analog electronic equiv. of the
mathematical operation of adding the logarithms of 2 numbers to multiply?

I hav not thought this through - it was just an off the wall idea, but...
sometimes a 555 can be the basis for a really elegant simple circuit. Is this
one of those times??

>  the core of a simple EFI is the
> > voltage to pulse-width stage.  If you use a 555 and simply alter the
> > threshold level you won't get a linear v to PW relationship.  A normal
> > 555 monostable uses an R-C network for the timing.  The voltage across
> > the capacitor rises in an exponential fashion,
>
>