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Print 24 comment(s) - last by snhoj.. on Feb 12 at 4:38 PM

Patent also shows aerodynamic wheels

Although there are numerous patents that get filed and never applied to real-life products, a couple of a few patents from automaker Audi have turned up that are reportedly going to be used in a production vehicle within the next two years.
 
The patents are for “active” aerodynamic wheels and an electric all-wheel drive system. The patent for the wheels shows a hinged flap between the spokes that move over the spokes of the wheels as speed increases. Once fully deployed, the hinged flaps create a flat wheel surface, reducing drag.
 
Active Wheel Shutters on the Ford Atlas Concept

Audi says that the fully enclosed wheels smooth the airflow and help improve the aerodynamics of the vehicle. When the car starts to slow down, the flaps reopen. The flaps are also temperature sensitive and if the brakes become too hot, the flaps open to allow cooling air inside.
 
It's hard to imagine the extra complexity of this sort of wheel justifying any fuel efficiency improvements gained by better aerodynamics, but the Germans are known for using overly complex electrical/mechanical systems.
 
Ford showed a similar active flap system with its Atlas concept truck at the 2013 Detroit Auto Show, but that feature didn’t make it into the all-new 2015 F-150.
 
Audi Quattro LaserLight Concept

The other Audi patent is for electric all-wheel drive technology, outlining a system with an electrically driven rear axle. The patent is for software systems that use sensors in the wheels to detect when the wheels break traction on slippery surfaces.
 
The patent outlines a system that would use regenerative braking that varies according to road conditions. The sensors would detect speed differences between the front wheels and rear wheels to determine how much braking force is appropriate.

Source: Autocar



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RE: Complex nonsense!
By snhoj on 2/10/2014 8:19:12 PM , Rating: 2
I think this regenerative braking system is coupled to the electric drive rear axle only. So the regenerative braking would only occur on the rear axle. The detection of slippage is so the regenerative braking will back off when the onset of skidding is detected so the car won’t become unstable under regenerative braking (think handbrake turns). Regenerating only from the rear wheels will make the system substantially less effective than full regenerative braking.


RE: Complex nonsense!
By flyingpants1 on 2/11/2014 3:39:44 PM , Rating: 2
Works fine on the Model S and all current EVs.


RE: Complex nonsense!
By snhoj on 2/11/2014 10:07:34 PM , Rating: 2
Nissan Leaf is FWD. Spark EV is FWD. Volt while not strictly speaking an EV is FWD. So not all current EV's regenerate through the rear wheels. The article wasn't about EV's but a hybrid. Front wheel only regen has more potential.

A number of factors will work against the effectiveness of rear wheel only regen. The vehicle featuring the electric rear axle will be a modified front wheel drive vehicle with a substantially forward weight bias. Less weight on the rear wheels means that less braking is able to be done by the rear wheels. Weight shifts forward during braking i.e. off the rear wheels meaning less braking is able to be done by the rear wheels. This would translate to a system capable of fairly low rates of deceleration under regenerative braking.


RE: Complex nonsense!
By snhoj on 2/12/2014 4:38:19 PM , Rating: 2
It occurs to me that there are factors which will mitigate these effects in the Model S. The model S isn't a converted FWD car so it doesn't have the forward weight bias. A higher portion of the vehicle weight is carried by the rear wheels. In fact 52% of its weight is born by the rear wheels so it has a slight rearward weight bias. The model S having its battery pack in the floor of the car has a very low center of gravity. This has the effect of reducing weight shifts during braking (and accelerating and cornering) to a minimum.

Tesla is developing an AWD version of the model S which should have very effective regenerative brakes.


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