ION-related IGN Comments & Coil Quest

[Bruce Plecan]

-----Original Message-----
From: Chris Rhodin <chris at imageio.com>
Subject: RE: ION-related IGN Comments & Coil Quest


Aren't those wasted spark coils that GM uses 4-wire coils?  You would just
use twice as many as GM and tie the other HV terminal to the ion-current
bias generator (an 80v zener that can handle the peak spark current and a
capacitor).

I think the hardest problem to solve for the ION sensor is going to be
overcoming the high-voltage nature of all the components in the system.  By
this I mean everything is designed to work with several thousand volts
applied, so nobody making parts (wires, plugs, connectors) really cares if
there is a connection at 80 volts.  There are even sparkplugs out there that
have an intentional gap in the body.

Once upon a time the staff at CSH HQ used to spend hours looking for the
lowest resistance of the resistance type sparkplugs.  As far
as on purpose gap, I've never seen that in AC, Champion, or Autolite.
This was about 10 years ago, however.

 And even if you get everything installed and working  you still will be
adding a failure mode to the system (if a small gap opens you still get a
spark but no ION current will flow).  I'm certain this is why Saab uses
those cute coils that connect right to the plug.

Chris Rhodin
chris at notav8.com

----------
From: garfield at pilgrimhouse.com
Sent: Wednesday, May 27, 1998 16:05
To: DIY_EFI
Subject: ION-related IGN Comments & Coil Quest

Thas all fer now. Scan yer personal archives and see if you've ever seen
a "4-terminal" IGN coil. Any feedback appreciated.

Gar