Batteries simply don’t have the energy density to compete with liquid fuels like diesel and gasoline. Thus, to achieve decent range, it’s important for EVs to make the most out of every last jiggling electron available. Often, aerodynamics are a prime concern to minimize the range lost to drag on long trips at high speed. Hyundai and Kia have teamed up on a new effort in this area, which involves using active aerodynamic elements to help its cars cut more deftly through the air.
Termed the “Active Air Skirt,” the device consists of a pair of wind deflectors that drop down ahead of the front wheels. The devices deploy at speeds over 50 mph (80 km/h), where aerodynamic drag becomes dominant compared to rolling resistance and retracts at under 43 mph (70 km/h). The difference between the two speeds is to stop the device from rapidly changing states at various speeds since the goal is to boost efficiency and not immediately break the thing.
This design was chosen instead of a full-width deflector due to the flat floor of the E-GMP platform vehicles it was designed for. It’s advantageous to deflect air around the front tires, but otherwise easier to let it flow under the body in the center of the vehicle.
At this stage, the device has been tested on the Genesis GV60 electric SUV. Hyundai and Kia have applied for patents in both South Korea and in America. Mass production is being considered, though that decision will depend on the perceived performance benefits, weighed up against the durability of the system.
The device is capable of safely operating at speeds in excess of 124 mph (200 km/h) and the deflectors are fitted with rubber on the bottom to protect against damage from debris at high speeds.
It’s worth noting, though, that the gains are actually kind of small. So small you might even wonder why the companies wrote up a press release. Apparently, the active air skirt reduced the drag coefficient of the Genesis GV60 test vehicle by 0.008. Given the GV60’s standard Cd of 0.29, that puts it at around 0.282. That edges it ahead of vehicles like the 2001 Toyota Prius (0.29) and the 2005 Chevrolet Corvette (0.286). The sizable SUV is still well behind cars like the Porsche Taycan Turbo (0.22) and the Lucid Air (0.197).
Put another way, the device improved drag figures by 2.8 percent. What you really care about, though, is how it really affects range. Well, it netted an extra driving range of 3.72 miles (6 km).
Sure, if you’re out on a lonely desert highway and the next charging stop is 3 miles away, you’ll be glad for it. Day to day, though? It’s not exactly much to write home about.
You might wonder why the flaps aren’t just deployed at all times. Well, realistically, they have less effect at low speeds. You could leave them out, but you’d have drastically reduced clearance at the front of the vehicle, making it more difficult to drive up ramps and driveways and the like. Thus, having them retract at lower speeds keeps them out of the way when they’re not contributing anyway. Hyundai confirmed for us that the air dam is retractable for clearance reasons.
Hmm, This All Seems Familiar …
This all might sound hip and modern, but alas, no! Active aero has been around for years, having something of a renaissance in Japan in the 1990s, before it became mainstream on European supercars in the 2000s. While we typically think of movable wings and spoilers, indeed, the Mk IV Toyota Supra had a similar device to the active air skirt seen here. Toyota also fitted an active air dam to the 2022 Toyota Tundra as well. One wonders how these similar systems would impact Hyundai’s chances of securing a patent for its active air skirt.
Hyundai has used more interesting active aero features on other vehicles, too. The Ioniq 6 features active air flaps that block off air to the car’s heat exchangers when it’s not needed. When closed, air hitting the front end is instead redirected to create an air curtain around the front wheels to further cut drag.
In any case, if these systems have been around for so long, why aren’t they on every car? Well, if they worked great and had huge benefits, they probably would be. Realistically, though, they offer limited gains. They also add some complexity to a vehicle, so whether that’s worthwhile comes down to an automaker’s need to get drag figures down. In an EV SUV, or maybe a truck with a certain MPG target, they can make sense. For a lot of other cars, maybe not so much.
Overall, it’s a neat idea, but doesn’t seem to be netting Hyundai any major range gains. On long highway journeys, you’ll likely see more benefit, but around town, the system would likely not even engage. Innovators will keep innovating, of course, but we’d say as likely as not, the Active Air Skirt might not be considered worthwhile for production. Time will tell.
Image credits: Hyundai
When I look at the front of this vehicle the Finding Nemo movie pops into my mind for some odd reason
I know of a few roads with 45 MPH limits and enough stop lights to make this thing resemble an upside-down whack-a-mole. Does it eventually trigger an error state if it triggers too often? Maybe it freezes in the retracted style and you don’t get it back until you power cycle the whole car?
Until they come out with super pursuit mode, this active aero this doesn’t impress me. I want the front end to split out, wings come out the side, giant spoiler in the back, bigger intakes/venting on the sides.
I’m usually in the ‘don’t put more widgets that will break on my car’ camp, but in the case of these things, I wouldn’t be upset by them. Cost/benefit ratio aside, if they are there and working, I get another 4 miles of range. If they fail, I lose that extra little bit of range, but the car will still be 100% usable.
Is the extra 4 miles worth the additional cost? If they were an extra-cost option I probably wouldn’t order it, but they bundle it with heated seats or whatever, I don’t think I’d be bothered.
Don’t they usually just make these out of something flexible? One of my cars had small deflectors in front of the wheels before they both got lost on separate occasions. Turns out that Audis with the factory dual side mount intercoolers do not appreciate plowing through feet of snow at speed. It gets rammed into the void above the fender liners and pushes them into the tires.
Perhaps not, but would some flexible rubber forward-facing mudflaps net some base level of improvement whilst still being able to pull into a steep drive (or plow snow) without complexities of active aero?
I feel like that’s a thing? Maybe not to the extent of this active one but like this:
https://cimg2.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/1261×840/img_0001_543e0e313c7ca932cf7015c78dc5ef6927d729df.jpg
Seems like any plastic will be flexible enough.
My Sportwagen has a small deflectors in front of the wheels that are static. Mine are all beat to hell because the car is lowered, but they’re still hanging in there. I think they’re part of the fender liner, so they aren’t actually individual parts. Which is probably why they’re still there.
“You could leave them out, but you’d have drastically reduced clearance at the front of the vehicle, making it more difficult to drive up ramps and driveways and the like.”
Those are bits of driving I do an awful lot slower than 50-43mph.
Well, even if you do driving up ramps and driveways slower, the point is that the skirt would collide with them…right? So I see why they wouldn’t install them as fixed parts.
I was questioning the speed at which they retract. They’ll be doing good work cutting aero drag all the time it’s moving, it seems weird to retract them at such high speeds.
If 4 miles doesn’t seem like a lot, try walking four miles. I have friends that work 3 miles from work and will never walk.
Its only like an hour of walking.
I’m a little surprised that it’s worth almost 4 miles on-cycle since so much of the cycle is at lower speeds. Running the numbers assuming a constant 60 mph – as you said, its 2.8% impact on Cd, and while it adds a little bit to the area, lets assume that the net effect on total drag force (CdA) is 2.5%. At highway speeds, aero drag is generally 70-80% of the total vehicle demand load (rolling resistance is the other big component, then bearing and brake drag etc). So an improvement of 2.5% on 80% of the vehicle demand load would be an overall improvement of 2%. If you’re getting 250 miles of range at constant highway speed, this is worth another 5 miles, and 6 miles if initial range was 300 miles (GV60 seems to be rated between 260-290 depending on trim etc).
If they got rid of the fake part of the grille and made it smooth, the same difference in range might be made. Downsizing the wheels and reducing the size of the wheel wells correspondingly would likely make yet more difference. The roof rack should be retractable. The rear should extend out a bit further with a more filled-in kamm-back. Add rear wheel skirts.
Lots to be gained from aero wheels on that too.
However, the objective here isn’t to make the most aerodynamically efficient car, it’s to make the most money selling cars by adding features that will appeal to customers or get free advertising. And it’s done that.
I wonder if ‘grill smoothing’ would become a popular* aftermarket accessory as I do think it’d yield some noticeable gains. Same with a rear wheel skirts.
*”popular”
The grill makes surprisingly little difference when the vents are closed (active grill shutters), because the air at the nose is fairly static. Additionally, the roof racks have minimal effect since the gaps are closed off. The back of the car has been heavily optimized for aero, and has already sacrificed a lot of cargo volume. Kamm-backing even harder wouldn’t really help much. The wheels are easily the biggest easy potential gain because luxury cars tend to choose looks at the cost of range here. Wheel skirts are also too uncool for luxury cars unfortunately.
All it takes is for one of the trend-setter brands to embrace fender skirts. If BMW can get away with that fugly pig nostril/beaver tooth grille, then they can get away with wearing a skirt.
Maybe they just need to make them more manly sounding. Brand it as “wheel kilts” and use some big burly Scotsman to advertise. “Outlander” is about to end, so Sam Heughan should be available.
Better this than spending time & effort on some useless off-road trim.
I remember the plastic cladding wars of the 1980s. New model? Add plastic cladding!