What's The Fan Belt For?

I read somewhere that it's for the water pump. Couldn't find this source, though. Hope my memory's good.

 

Seems I read about this maybe one time somewhere and I can't remember the details.
I seem to remember it has something to do with the fact that once the engine is warmed up, it goes to convection heating or something of that nature... it starts electric and moves to belt only when the ice is one to save electricity.
While the ICE is one, it may as well do some work rather than pull from the batteries?.... \



Someone can correct me I hope, but it is something of that nature.

 

From my perusal of the Prius manuals:

A/C compressor is electric (belt-driven in the classic);
Power steering is electric;
Camshaft is chain-driven;
Engine coolant pump is belt-driven;
Heater coolant pump is electric;
Inverter coolant pump is electric;
The oil pumps for the engine and transaxle are mechanical and integrated;
The only cooling fans are the two electric radiator fans.

So the belt Vincent saw is driving the water pump. And the Prius can never be totally silent, as the inverter coolant pump runs continuously.

 

Looks like the only thing belt driven is the Engine coolant.. I guess it doesn't need to churn if the ICE is off.. so I guess that works good... again.. why tax the electric system for anything that truely only needs to be on while the ICE is on?.. Might as well let the ICE carry the load mechanically.

 

Is such electric pump used somewhere?

The belt driven pump is low cost, reliable and proven technology for many years.
There is no reason for Toyota to do such gambling on the current Prius.
Maybe, someday in the future...

Ken@Japan

 

That was a rhetorical question, Ken...

 

Is that the high-pitched whine you hear when the car is on but nothing is running?