Electric cars and cooling drag

[Autobahnschleicher]

Another issue is that water cooling might not be the ideal solution for BEVs as it relies on having a significant deltaT.
One system that might work more efficiently would be to cool the drivetrain directly with a phase change cooling system that can operate as a liquid cooling system as well by using additional reservoirs as well as a bypassable expansion valve and a controllable pump.
Nice side effect:
One could reverse the pump to heat the battery/interior during winter.

[freebeard]

Huh?

We have no idea of the proportional cooling drag of the 1947 Volkhart-Sagitta versus the KdF-Wagen Type 60.

Perhaps. The cooling load is held constant (for a given engine RPM), while the Cd halves.

[Vekke]

Originally Posted by Isaac Zachary

Apparently the Aptera is going to have 0% cooling drag.

And there you have it zero drag penalty in ev from cooling system. They use panel coolers and beause their car is so aerodynamic it can go away with zero drag penalty at least that is what they claim.

No paper to prove that claim at the moment, but eye can tell that migth be true as there is no cooling inlets to be seen.

That same system would not be possible in ICE vehicle as it creates so much more extra heat.

Edit:

Ofcourse the cooling drag is newer zero as water inside the cooling system or the air circulating inside cabin creates also drag to some degree. So there is cooling drag, but minimal to none aerodynamic drag extra from cooling.

[JulianEdgar]

Originally Posted by Vekke

And there you have it zero drag penalty in ev from cooling system. They use panel coolers and beause their car is so aerodynamic it can go away with zero drag penalty at least that is what they claim.

No paper to prove that claim at the moment, but eye can tell that migth be true as there is no cooling inlets to be seen.

That same system would not be possible in ICE vehicle as it creates so much more extra heat.

And there you have it: Vekke talking out of his hat, yet again!

Some ICE cars have zero cooling drag.

Maybe do some detailed research before commenting?

[Vekke]

I just wrote what aptera engineers said on the video I watched one week ago. If you think they don`t know what they are talking about go teach them how the make their car even better. I am sure they like to make it even more efficient.

I really don`t like the way you think you know it all. If you have nothing add extra information about the topic why comment something which is not true and blame others?

[JulianEdgar]

Originally Posted by Vekke

I just wrote what aptera engineers said on the video I watched one week ago. If you think they don`t know what they are talking about go teach them how the make their car even better. I am sure they like to make it even more efficient.

Again, I am not sure if it is a language issue but that is irrelevant to what I wrote.

I really don`t like the way you think you know it all. If you have nothing add extra information about the topic why comment something which is not true and blame others?

And in turn, I don't like it how you make multiple (over many posts) pseudo-definitive statements that are actually completely wrong and so are misleading of others.

We've seen how, unfortunately, your on-road testing techniques are laughably bad and your claims of drag reductions (again, unfortunately) are quite ludicrous.

Now you make statements like; "That same system [ie zero cooling drag] would not be possible in ICE vehicle as it creates so much more extra heat." Again, completely wrong.

Ignorance (in the true sense of the word) is always fine, misleading others through definitive statements, that are in fact wrong, is not fine.

Do some research - buy those SAE papers, talk to top car aerodynamacists, do proper on-road testing. Yes it costs money and takes effort. That's the real world.

I never, ever, ever, make statements here that I can't back up with evidence like this.

It would be much better if others, like you, did the same.

[Vekke]

Can you show that ICE vehicle where there is that 100kW (2x50)or 150 kW (3x50) engine power and zero cooling drag like the Aptera has, that is what you are saying that is possible to make?

[planetaire]

Hi, Vekke

I found a paper about a car for which the front radiators air drag is considered equal to zero.
Probably Julian is talking of this car.
But this car don't answer to Julian sentence:

Some ICE cars have zero cooling drag.

Because on this paper only the radiator cooling drag is said being zero drag.
They don't speak about the exhaust drag, muffler, catalyst cooling drag. This devices need cooling.

And this zero drag is not because there is an ICE engine, it is because a clever engineer found this idea. The same would be possible for Bev car, Phev car ...

This idea is to send outlet air coming from radiators in front of the front wheels.

[JulianEdgar]

Originally Posted by planetaire

Hi, Vekke

I found a paper about a car for which the front radiators air drag is considered equal to zero.
Probably Julian is talking of this car.
But this car don't answer to Julian sentence:



Because on this paper only the radiator cooling drag is said being zero drag.
They don't speak about the exhaust drag, muffler, catalyst cooling drag. This devices need cooling.

And this zero drag is not because their is an ICE engine, it is because a clever engineer found this idea. The same would be possible for Bev car, Phev car ...

Yes that is an interesting point.

When I am talking about 'cooling drag', I am talking about the cooling drag of the radiators. This is the approach taken in all technical aero literature, so I feel pretty relaxed about taking this approach.

(In fact, the research I am conducting for my current book appears to indicate at least one car had a negative drag (ie thrust) from the cooling system! But that's another story.)

[JulianEdgar]

Originally Posted by Vekke

Can you show that ICE vehicle where there is that 100kW (2x50)or 150 kW (3x50) engine power and zero cooling drag like the Aptera has, that is what you are saying that is possible to make?

Huh? Have you been taking lessons from Aerohead, where the goalposts are moved when the argument is lost?

You said:

"That same system [ie zero cooling drag] would not be possible in ICE vehicle as it creates so much more extra heat."

This is wrong, and references to the Aptera (for which no data is in fact even available... but hell, who cares?) are irrelevant.

Muddy the water, anyone?