Aero comparison of electric charge doors vs. manual

[TDinDC]

I have to agree, I too really like the Power Port Charge Cover. The test was well done but it would need to be a pretty big difference for me personally to forego the power port covers. I just like the way they look and operate.

I like it because I'm lazy. I'm still annoyed that I have to open and close my own door or the doors of my passengers! Delays me too much as I am going to the gym.

Sponsored

 

[Fish Fingers]

I like it because I'm lazy. I'm still annoyed that I have to open and close my own door or the doors of my passengers! Delays me too much as I am going to the gym.

I love the way at gyms how everyone tries to get the parking bays as close to the front door as possible..... before going inside and doing 10k on the treadmill.

 

[f1eng]

I like it because I'm lazy. I'm still annoyed that I have to open and close my own door or the doors of my passengers! Delays me too much as I am going to the gym.

The electric covers probably save as much as 0.5 secs per use if you operate them from inside the car as you arrive but are probably actually slower if you use the gesture/touch sensor rather than just opening them.

They are a fun gadget, which may go wrong. Nothing about them saves time

 

[TDinDC]

I love the way at gyms how everyone tries to get the parking bays as close to the front door as possible..... before going inside and doing 10k on the treadmill.

I’m glad you get my sense of humor!!

 

[Kingske]

or much easier with CFD nowadays and only finally check the results within an expensive wind tunnel.

improving the aero are many, many tiny steps that may eventually result in a noticeable result, but my idea was to answer the question of omitting the electric charge doors can have an effect you really would notice somehow in the decimals of you long term consumption, and I doubt it very much, although Porsche's Nardo test cars had manual doors.


BTW: I edited the first introducing text and the PDF to make it a bit clearer I hope.

Maybe @Wouter Remmerie can shed some additional light?

https://www.taycanforum.com/forum/threads/porsche-taycan-aerodynamics-features-video.5227/post-72307

 

[Midlifecrisis]

The electric covers probably save as much as 0.5 secs per use if you operate them from inside the car as you arrive but are probably actually slower if you use the gesture/touch sensor rather than just opening them.

They are a fun gadget, which may go wrong. Nothing about them saves time

They do save time when you finish charging - every time. Just unplug and leave them to close themselves. Sort out the charge cable and the door will take care of itself. I specced the as an afterthought- really pleased that I did.

 

[Midlifecrisis]

They are also good if charging in a tight space as they don’t stick out, held wide open by the charge cable. Most other EVs do this and it is quite annoying if you have to squeeze past them

 

[TDinDC]

The electric covers probably save as much as 0.5 secs per use if you operate them from inside the car as you arrive but are probably actually slower if you use the gesture/touch sensor rather than just opening them.

They are a fun gadget, which may go wrong. Nothing about them saves time

Each small time savings may not seem like much, but if you add enough together, you might find yourself on the Island of the Day Before.

 

[Gnasher]

The electric covers probably save as much as 0.5 secs per use if you operate them from inside the car as you arrive but are probably actually slower if you use the gesture/touch sensor rather than just opening them.

They are a fun gadget, which may go wrong. Nothing about them saves time

Wait till you get your car mate.

For me it’s about opening in the car and then just plugging the cable in using one hand and not having an ugly flap open.

For me the manual option just looks cheap on a £100k+ car.

 

[submatrix]

I have the manual flap and I will admit the electric one looks cooler opening and closing. I'll also add that it usually takes me more than one attempt to close the manual flap. You have to be really deliberate about pressing it in so the latch catches.

 

[Vercingetorix]

Measure steering wheel input while coasting. 2 people in car of equal weight. Completely flat surface. One vent open the other closed. Aero drag will cause a steering input to correct for. Probably nearly impossible to determine any difference.

 

[jvincent]

Charge port configuration is a matter of choice, but fake vents are shameful, especially on a Porsche.

 

[Fish Fingers]

I’m glad you get my sense of humor!!

Thinking about it, I could save gym members the cost of membership.

Suggest they park their car 5km away from the gym. Jog to the gym and touch the front door, then jog back to the car.

Same result as doing 10km on the treadmill, but at no cost.

 

[Wouter Remmerie]

Maybe @Wouter Remmerie can shed some additional light?

https://www.taycanforum.com/forum/threads/porsche-taycan-aerodynamics-features-video.5227/post-72307

Supercool to see the data of the tests they performed.
Some comments, many of which have been mentioned before:
- The goal of an "air breather" as BMW and perhaps others call it is indeed to evacuate some of the high pressure air in the wheel wells (the wheels rotate and spin the air, building up pressure). Evacuating this can help to reduce the amount of air being splashed out sideways.

Also, the air can be channeled alongside the door panels, eventually ending up at the rear wheels. There, it may help to create a moderate air curtain around the rear wheel to help shield that one as well.
- The tests do show a lot of variation and thus it is very hard to conclude anything. Which makes sense, as you would not expect the effect of an air breather to be more than 1-2%, order of magnitude.
- The height difference, for example, is 21 meters (-16 versus +5). That represents an energy difference of E = m * g * h = 2200 kg * 9.81 m/s² * 21m = 453 Joules
Spread over 90 seconds, that's 453 J / 90 s = 5 Watts
This was spent over a 5km stretch, so translating this to 100km results in 5 Watts * (100 km / 5 km) = 100 Watts, or 0.1 kWh.
Doesn't explain the full difference (48.3 kWh/100km versus 46.7 kWh/100km), but a lot of small details can bias the results.
- Coastdown testing is a tricky business. To learn how it works - see this video.
- The type of wheel rim / cover can have a tremendous impact on aerodynamic drag / range / ...
We did such a virtual experiment on a Ford F150, mounting Tesla model 3 covers (after scaling them). See this video for the results!

In conclusion:
very likely the breathers help to lower the drag, but in the order of magnitude of perhaps 1%. So very hard to capture with road testing where other variables have a lot of impact.

 

[rs38]

glad you are in here, didn't notice it. may be you remember my question during your online event:

very likely the breathers help to lower the drag, but in the order of magnitude of perhaps 1%. So very hard to capture with road testing where other variables have a lot of impact.

why guessing? I think you have all the tool and models to get concrete results of the losses?

- The height difference, for example, is 21 meters (-16 versus +5). That represents an energy difference of E = m * g * h = 2200 kg * 9.81 m/s² * 21m = 453 Joules

I excluded the height for a reason I may explain: the height channel of normal GPS devices (Smartphone in that case) is usually too unprecise to use it more than than a rough plausibility check if the test run was okay or not.
Usually I use professional test equipment from Racelogic (Vbox etc.) which are providing much better (doppler based) velocity vectors like vertical speed with at least 10Hz. This is proven to be usable like "okay" in meters but still has less precision as horizontal precision which is nearly to cm, but always very important to have good GPS reception and an external antenna, especially with the solar insulated glass option.

and even more difficult with the glass roof where you need to go sure to have a reflecting surface done with aluminum foil.