Low temp thermostat

[David C. Allen]

I am talking about the operation of the thermostat, a mechanical open loop 
of the cooling system or closed loop, where the thermostat, is able to 
control the engine temp via coolant flow.

Sorry for the confusion, but I am almost 50

David

At 07:10 PM 10/27/1999 -0500, you wrote:
>Properly tuned (note, the phrasing), an engine will live as long or longer,
>and use less fuel in open loop, IMHO.
>   I have to do some more actual work on this but intial reporting, from
>programming 101 seem to support this.
>   Closed loop is for maintaining a 14.7:1 AFR.  Which assumes several things
>ie the formula for the fuel at hand is close to what is expected of it.
>To keep the Catalytic converter hot enough to function.  There is more
>detail in the archives about the rich len cycling of the AFR to keep the
>converter working.
>   Open loop or closed loop is a matter of tuner's preference.  Or for EPA
>testing.  I'm not too sure where we'd be since I don't have a gas analyzer,
>but I bet ya it could be clean enough for most applications.
>   Higher operting temps. make radiator cooling an easy function, try 165 for
>on temp., and 205 on a warm day.  THe on time for my car went from almost
>never to always on.
>   Grumpy
>
> >I thought that the object of game was to keep the thermostat in the closed
> >loop mode. It should only be in open loop during initial warm-up. The ECM
> >can try to change engine operation during upper engine temperature
> >excursions, but it can not change the outside temperature or the fact that
> >you are stuck in traffic. In the Suburban 1227165 TPI project, I plan to
> >change from a engine driven cooling fan to twin electric cooling units
> >which I can control via the ECM. With air conditioning you could/will add
> >heat to radiator because of the airflow path, the ECM knows head pressure
> >and engine temp so it could short cycle the compressor, and add additional
> >cooling to lower AC head pressure.
> >
> >So I think the selection of a thermostat operating temp and strategies of
> >how to keep the thermostat in a closed loop operation is a very important
> >part of the gm ECM discussion. I would like to hear more!
> >
> >David
> >