RE return to fuel tank

[Gary Derian]

The 1999 BMW V-8 engines have just introduced ECU controlled engine temp.
Cooler WOT and warmer at cruise.  Engine temp doesn't have to change with
throttle position, just cooler with sustained WOT like on the autobahn.
Here in the good old US, a fast car never runs WOT more than 10 seconds,
even a slow car doesn't run more that 30 sec.

Gary Derian <gderian at cybergate.net>

>
>>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
>