heat pipes for car engines?

[boffin15]

My goal is to design a IC engine cooling system with an inlet and exhaust, and the least possible resistance to airflow through the cooling matrix. With conventional radiators there is substantial restriction with the fin and tube construction. I am looking at using a liquid heat sink for the engine cooland, with heat pipes extending into the air ducting. The idea is that heat pipes are very efficient at transporting heat, and so can be made smaller with minimal obstruction to airflow.
This may have already been done, or maybe not due to fundamental technical issues. I would appreciate any and all comments on this pursuit.
Alan w

 

[RVAmeche]

Are you talking about using engine coolant to heat the cabin air? Because that already exists and is called a heater core.

If you're talking about using a liquid/liquid heat exchanger instead of a normal air/liquid radiator, that also exists but is only found on race cars and applications requiring the extra heat transfer.

 

[IRstuff]

I would suggest that you first figure out your heat load from the engine and then figure out where you think can get the air convection to remove that heat.

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[Compositepro]

There is little difference between the current cooling systems of cars and a heat pipe. A heat pipe moves heat by boiling a liquid and returning the condensate by gravity or by wicking. Current cooling systems use a pump to move only liquid, and avoid vapor flow. Both methods are very effective at moving heat, so that is not a factor.

 

[3DDave]

Forced heat transport is more effective than convective heat transport. It also allows for the use of rubber hose to decouple the motor motions from the rigid vehicle chassis.

Maybe for an electric motor? Still, using a separate return circuit for coolant seems certain to be more effective for similar mass of cooling system. Even with a heat pipe, one needs surface area to transfer the heat from the coolant to the air; how does using a heat pipe change the amount of air contact required?

 

[Compositepro]

Quibble: "Forced heat transport is more effective than convective heat transport."

Convection can be forced or natural, but both are still convection. Convection is heat transport due to mass transport.

 

[3DDave]

OK - quibble noted. Forced convection in normal automobile cooling vs natural convection in heat pipes.

 

[IRstuff]

At the end of the day, the heat pipe itself cannot provide the cooling, merely the convenient transport of heat from an awkward location to a more manageable location. That still requires a heat exchanger with direct access to air flow from the car, and given the undesirability of putting fins on the outer surfaces of the car, the existing radiator location is pretty much ideal, as borne out by the fact that few cars have radiators elsewhere.

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[btrueblood]

As others have said or implied, the limit is on the air convection side of things - the h for air is a couple orders of magnitude lower than the h for water or water/glycol.