RE return to fuel tank

[Greg Hermann]

>Many good points here!
>
THANK!!

>Why is not engine temperature controlled by ecu? Warm engine for light
>cruise ,cold for wot.Warmer engine at cold outside temp.....

Changing temp with every throttle movement would cause a great deal of
thermal stress in the engine (and related wear), and would not happen fast
enough to make any difference anyway (too much thermal "inertia" in
engine).

BUT--if one wanted to spend  money for an active control, temp could
certainly be held closer to a constant value than it is with current art.
AND it could be varied up or down (somewhat) to suit outdoor temp (weather)
since this does not change very fast.

An active control valve could most certainly be programmed to anticipate
changes in cooling system load based on sustained changes in load and also
to avoid the offset in operating temp which occurs say from going toward
hot side going up a long grade with a trailer to going on cold side going
down the other side!! (Eliminating control setpoint offset is precisely
what the I (integral) in PID control does!)

>Thinking loud again.....
>Espen Hilde

Thoughts are wonderful things!

Regards, Greg