Thing is if you're going to drive an alternator from a belt and then use
that electricity to drive a waterpump and fan, you might as well drive the
waterpump and fan directly. When we get high voltage alternators that are
part of the flywheel so no friction from the drive, things might be
different. I dunno how much power a waterpump devours, and whether the
ability to vary its output independant of engine speed would be useful or
not, though. But I'd say viscous coupled fans are pretty efficient - and
rather longer lived than the average electric fan - if the aux one on the
E39 is anything to go by. ;-)
*Certain frogs can be frozen solid, then thawed, and survive *
Dave Plowman email@example.com London SW
Well, sort of... My thought was with electric auxiliaries, you can turn
them on and off with intelligent controls rather than just having them
run all the time that the engine is running.
For instance, running a water pump full time, or the fan full time, even
though the engine may not need them.
I also recall reading somewhere that a pusher fan is more efficient than
a puller type such as one driven off the engine.
That is true and has worked for years, but given the need to enhance power
while lowering fuel consumption, an electric driven water pump and radiator
fan makes a lot of sense. I agree with Fred on this. I found the article I
was lloking for, and BMW is using an electric water pump (engine cooling,
not just heater core flow) in the E90...and their results indicate the
savings from the pump compared to the increased load on the alternator, is
well worth the change.
I had a friend with a large car in times past. It was some kind of Buick and
had a huge fan and a large space between the fan and the radiator, with a
giant cowling coupling the radiator to the fan.
Well, he parked it one day at another friends house, a cold autumn day and
we went inside to suck back on some wobbly pops.
When we went out and started the car, the most horrible whining sound came
from under the hood, we stopped the engine and a cat ran out from underneath
the car. The cat was not injured, just scared to death.
It had sat in close to the radiator to get warm.
After that experience, any time a car pulled up in the driveway, the cat
would run in the other direction.
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