All this talk about electric water pumps raises a few questions:
1) If the pump and drive pulleys are sized for adequate coolant flow
at idle will the pump caviate at red-line?
2) How much power does the pump use?
The Pump question is much like the fan question with the exception that
there is no induced coolant flow form the forward movement of the vehicle
as there is with the air. So if the pump were driven from an electric
motor
what speed would be used?
The Ideal setup would be to use a variable speed electric drive using
coolant temperature to determine the pump speed.
On start-up a cold engine requires no pump at all. As the engine begins to
warm up the pump would be required to allow the heater to work. Once
warmed up, the engine would need a modest amount of coolant flow at idle.
At speed, underload the coolant flow requirements would increase but
not as a function of speed of the engine but as a function of the load and
the heat generated.
I could design such a system for, oh, about $10,000 complete with working
prototype. ;-)
Talk about gilding the lilly. Or is it Rube Goldgerg?
Seriously, though, one advantage to an electric driven pump is that it can
continue to run after the engine is shut off and cool down the motor
between
runs (eg:at an autocross) a la John Lye.
Dave Massey
St. Louis MO USA
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