Date: Sat, 2 Jun 2001 17:37:22 -0400
Reply-To: 72510.1173@COMPUSERVE.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Helen Fahy <72510.1173@COMPUSERVE.COM>
Subject: Re: Ignition? Constant Duty or Constant charge
Content-Type: text/plain; charset="iso-8859-1"
Just thinking outloud, as the Haltech I have on an old Porsche does not have
ignition mapping. Could the constant duty describe a single ignition event
(a spark) per ignition stroke and the constant charge be a description of a
multiple spark system. The constant charge would be defined at high rpm,
where the charging of the capacitor is time limited. At low rpm the system
would trigger multiple constant charge sparks, as rpm increased the number
of sparks per ignition stroke would decrease until at some rpm only one
spark would be triggered per ignition stroke.
The engine would run under either system. It might run smoother under
multiple spark depending on the specifics of the engine. I believe that the
coil will get hotter under the multiple spark system and there will be the
potential for more RFI .
If I am wrong, I have not spoken to Haltech in Ca or Au for a few years, let
me know, OK?
BTW is the throttle position switch (TPS) an input to the Haltech system you
have? If so, how granular is the fuel and ignition mapping just off of
idle? On my old system the TPS is a linear potentiometer which give really
poor throttle position information just off idle, a log pot would allow more
maps to be created where the throttle is just beginning to open. I am going
to emulate a log pot with the linear one and an additional resistor, the
only problem is the current that this ersatz log pot will demand is larger
than the linear pot. I hope that I do not let any smoke out. Other more
expensive engine management systems allow selective placement of maps at
user configurable points along the rpm axis. Maybe the price has come down,
I need to check these again.
How did you develop the fuel & ignition maps? Could I see them?
Have a good one,
Joe Fahy
----- Original Message -----
From: "Max Wellhouse" <maxjoyce@IPA.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, June 02, 2001 3:21 PM
Subject: Ignition? Constant Duty or Constant charge
>
> On one of the ignition maps on this haltech FI system, ity has a choice of
> "constant duty" or" Constant Charge" type igniton. Does anybody know what
> style the vanagon ignition falls under using this terminology? The engine
> runs under either mode, but in constant charge, the laptop program gives
off
> some sort of millisecond reading. Just doing a little tweaking here and
> there.
>
> TIA
>
> DM&FS
