EST Systems

[J.W. Harris]

>When  you  say  "limit  dwell  time  internally", do you mean that the
>module automatically turns the coil on again at some fixed delay after
>EST has been triggered, regardless of the current state of EST? I'd be
>dissapointed if this was the case, since  I  had  planned  to  have  a
>variable  dwell based on RPM to keep the power dissipation in the coil
>to a minimum. (still referring to the standard GM 7 pin module)

I think I saw somewhere that some modules will limit dwell if it exceeds a 
maximum value.  It might just limit current or both.  I'm not sure.

>
>One other question: is the Refernce output of the module just a signal
>conditioned copy of the pulse from the pickup? The  reason  I  ask  is
>that  I also wanted to use the method of having one wider tooth on the
>reluctor to indicate cylinder 1, thus having a  reference  for  engine
>position.   If  the  Reference  is  a straight one-shot pulse of fixed
>width regardless of what pulse width the pickup  sees,  I'll  have  to
>scrap  that  idea  and  use  some  other  method of determining engine
>position.

I don't know what kind of signal conditioning is done, if any.  It probably 
works like a comparator with hysteresis.  However, I don't think making one 
tooth wider with a VR sensor will work.  It would be impossible to measure 
the resulting waveform with enough accuracy to distinguish that tooth.  A 
better solution is to add an extra tooth and have S/W recognize when it is 
passed.  Or use a wheel with many teeth and detect one that is missing.
----------------------------------------------------------------------------
J.W. Harris                                          Delco Electronics Corp.
Project Engineer                                     One Corporate Center
Powertrain Electronics                               M.S. CT40C
                                                     Kokomo, IN 46904-9005
jwharris at kocrsv01.delcoelect.com

Of course, all responses are my own and should not be mistaken for those of
Delco Electronics or General Motors.