Opportunity to reduce aerodynamic drag?

[alohart]

From http://www.bmwblog.com/2014/11/11/look-bmw-i3-underneath/:

What's with the large triangular opening under the rear of the i3? Would covering that triangular opening with a nice piece of sheet aluminum reduce aerodynamic drag a bit? There even appear to be holes available for mounting this sheet. In a BEV with no ICE to generate heat in that area, I doubt that the enclosed area would get too hot.

 

[Idleup]

Great Image Thanks - I can't see why it would hurt - my guess it would add a few miles and if nothing else keep the cavity clean of road grime!

Mike

 

[WoodlandHills]

Would it affect battery cooling in hot weather? If not give it a try.....

 

[mindmachine]

I would not do it especially if you have the Rex as the batteries are cooled but the Rex is air cooled and I don't see anywhere else for the Rex to get air flow from. Plus it could have an adverse effect on the battery cooling too I suppose.

At least in my book, as heavily engineered as this car is to get the most range out of it (ie carbon fiber body) I seriously doubt they would have overlooked this as a source of added advantage to achieve that goal. They left it open for a reason, I would bet.

 

[GodFollower]

Well, on a BEv that is how the A/C compressor is cooled. It sits on the front of the drive eMachine, and especially in hot weather can get pretty warm.

And Mindmachine, the REx is actually liquid cooled-the engine has it's own high temperature coolant circuit in the vehicle. The REME and REM are cooled by the low temp cooling circuit the drive eMachine is on.



And for what it is worth, there are very large air outlets on either side of the rear drive module. If you had a picture of the wheel wells you would see what I mean, you can see the drive eMachine on the left and the REx assembly on the right, through large openings.

On a REx model there is a fan in the left opening, but still not obstructed.

 

[mindmachine]

Well, on a BEv that is how the A/C compressor is cooled. It sits on the front of the drive eMachine, and especially in hot weather can get pretty warm.

And Mindmachine, the REx is actually liquid cooled-the engine has it's own high temperature coolant circuit in the vehicle. The REME and REM are cooled by the low temp cooling circuit the drive eMachine is on.



And for what it is worth, there are very large air outlets on either side of the rear drive module. If you had a picture of the wheel wells you would see what I mean, you can see the drive eMachine on the left and the REx assembly on the right, through large openings.

On a REx model there is a fan in the left opening, but still not obstructed.

Even so what do you think about closing up this area. I do not think it is a good idea as BMW probably would have put a plate there if the cooling it provides is not essential for whatever subsystem.

 

[jelloslug]

I'm fairly certain that BMW left that area open like that for a reason. I'm assuming that it has to do with cooling.

 

[websterize]

I'm fairly certain that BMW left that area open like that for a reason. I'm assuming that it has to do with cooling.

Couldn't have typed it better.

Leaving the space open is likely the lesser of two evils, and even then, the drag coefficient in the production I01 is very good, about ~0.29 as I recall.

 

[Lincsat]

I would be more concerned with water ingress rather than drag.

 

[jadnashuanh]

I would be more concerned with water ingress rather than drag.

Things that need to be sealed already are...I wouldn't worry about it in the least.