Water pump clutch

"Losing ICE heat through radiator." Isn't that what it has a thermostat for ... so coolant isn't passing through the radiator?

 

Isn't the water pump electrically operated though?

-- Ian

 

Yes it is...

 

Not totally, it has both Denso the maker says:

The Prius's main water pump loses its source of mechanical energy when the vehicle is running on battery power alone and the engine is off. So, we developed an auxiliary electric water pump for the car. Our electric water pump provides a constant flow of heat to the cabin even when the mechanical pump is stopped. The mechanical pump operates when the engine is running, which reduces the load on the battery. And a bypass function reroutes water flow to avoid resistance from whichever pump isn't running.

 

I stand corrected. I just found it in the Repair Manual. Yes it does have both.

 

well we dont want hot spotting, i guess all you need is a variable electric water pump

 

Hmm...

Anyway, the radiator only functions when thermostat opens the path to the radiator. No opening, no flow.

However, another consideration could be the extra energy needed to turn the waterpump when warp-stealthing.

 

honestly i like the current design, gives me piece of mind, its not much power used to turn a water pump anyway.

it would be cool if antifreeze would be made of special bacteria that propels itself through the engine and into radiator, and so on.

 

Re: Flow producing bacteria -- "hybridized" dynoflagellates?

What would you feed the little critters?

 

There is a lot of misunderstanding re thermostats. When the thermostat is closed there is still some flow through the rad. It's through the heater circuit (which also has a bypass around the heater). This is done to avoid or reduce thermal "spikes" when the thermostat operates, to avoid a large pressure differential across the thermostat, to allow some flow through the engine to avoid hotspots, and to give heat to the heater sooner. The throttle body heater also works off this circuit of coolant.

 

we should use air cooled engines

 

Air cooling only sounds good. It's simple and cheap. But in practice air cooled engines use tons of energy to turn a huge fan, yet still run so hot that they have to run very low compression ratios, yielding low power and low efficiency. The high cylinder temperatures also make it unavoidable to have high smog-forming emissions (NOx). I doubt at this point anyone could make an air-cooled engine meet US vehicle emission standards at all.

Air cooling is why the classic VW Beetle, despite being small, very light, and with no excess of power, never got more than about 25 mpg. When small, affordable Japanese cars with water-cooled engines reached the US market, the Beetle was instantly obsolete. It used more gas, had less power, wimpy cabin heat, and was impractical to rig up with air conditioning too.