Really?

"ttyymmnn" (ttyymmnn) 02/05/2016 at 08:59 • Filed to: None

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The NYT has an !!!error: Indecipherable SUB-paragraph formatting!!! this morning about automakers experimenting with cameras and interior screens to replace side view mirrors (honestly, I imagined something like that 30 years ago, but the technology just wasn’t there). Anyway, here’s a quote from the article

“There’s significant noise reduction, and there’s potential for CO 2 reduction because of reduced drag and improved fuel economy,” said Dean McConnell, director of customer programs for advanced driver assistance systems at Continental. “There’s also the increased field of view.”

Okay, I’ll give him the noise reduction, and I’ll give an increase in field of view. But reduced CO2 emissions? Really? Reduced drag? Yes, the mirrors produce drag. But seriously, just how much? And would removing them really make that much of a difference? That said, I’m sure the only reason they have mirrors in F1 is because the FIA mandates them. But still, I’d like to see the fuel economy and emissions data from a car with and a car without side mirrors. Maybe I’d be surprised?

The thing is, with outside mirrors (if you use them, many don’t), you see more than just what’s reflected in the mirror. Looking outside increases your situational awareness. You are likely to see many things that are not visible in the mirror. I heartily believe that tech isn’t the answer to everything. We don’t need more screens in our car. We need to get our head out of the cockpit and see what’s around us. Why not replace the windscreen with a big LCD screen fed by cameras on the bumper?

ETA:

Mr. Hoffmann pushed a button and the rearview monitor image transformed into a virtual panoramic rear view that electronically stitched all three camera pictures into a seamless image. The resulting live image made it appear as if nothing was behind the driver to obscure the view.

Okay, this would be cool.

Photo by Continental via the !!!error: Indecipherable SUB-paragraph formatting!!!

bob and john > ttyymmnn 02/05/2016 at 09:07

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yes, youd be surpirsed at how much extra drag those two little 20cm by 10cm square add up to.

Eric @ opposite-lock.com > ttyymmnn 02/05/2016 at 09:12

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It’s a distinct drag reduction. All cars aiming for high fuel efficiency for decades now have been pushing to replace wing mirrors with cameras or mirrors that don’t protrude.

The only reason they've held on so long is that they're enshrined in vehicle codes.

jariten1781 > ttyymmnn 02/05/2016 at 09:20

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I don’t remember the order of magnitude but it’s a noticeable drag difference.

Agree that screens cause a loss of situational awareness. They also cause you to have to shift your eyes’ focus from infinity which isn’t a trivial change. I bet it’s not particularly significant safety-wise either way though.

Also, if people treat them like they do their backup cameras they'll be useless once the first salting is laid down since no one is going to bother cleaning them. Good times.

davedave1111 > ttyymmnn 02/05/2016 at 09:25

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Have you ever stuck your hand out of the window at 70mph+? Yes, wing mirrors add noticeable amounts of drag.

Other than that, they’re also positioned in such a way that the effect on wind-noise inside the cabin is very large. The turbulence coming off them runs up against the window glass right by where the driver sits.

TheHondaBro > ttyymmnn 02/05/2016 at 09:33

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Mirror farts.

ttyymmnn > davedave1111 02/05/2016 at 09:35

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I guess I wasn’t clear, because I was really questioning the bit about reduced CO2 emissions. But beyond a discussion purely on aerodynamics, I am still interested to know just how much the mirror drag affects efficiency. Numbers. Data. I believe you all when you say it has an effect, I’m just wondering how much, particularly if that amount is not negligible.

MontegoMan562 is a Capri RS Owner > TheHondaBro 02/05/2016 at 09:37

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The true enemy of the Ozone Layer

davedave1111 > ttyymmnn 02/05/2016 at 09:41

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~5% seems to be a reasonable average figure.

http://metrompg.com/posts/mirrors.…

Or this if you want way more detail:

http://publications.lib.chalmers.se/records/fullte…

BvdV - The Dutch Engineer > ttyymmnn 02/05/2016 at 10:15

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Well I think the impact of the mirrors is larger than expected due to the disturbance of the air flow around the car. The Nissan Leaf even has headlights shaped in such a way that the air flow will not pass the mirrors as much, and thus won’t be disturbed by them as much.

unclevanos (Ovaltine Jenkins) > ttyymmnn 02/05/2016 at 11:00

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I still prefer mirror glass, when people complain about the complexity of power mirrors I should just show then this. I like the fact that the camera will be useful in adverse weather conditions. I know vw implemented it on their XL1.