All for the purpose of reducing drag
Together with clever engine innovations, aerodynamics also plays a key role when it comes to making an energy-efficient car.
When air does not pass smoothly through a car's body, it creates something called drag - it's the force that slows a car down. And in fluid dynamics, the drag coefficient (Cd) quantifies the drag or resistance of an object in a fluid environment. Of course, the greater the drag (Cd) value, the greater energy is needed from the engine (or electric motor) to keep the car moving.
From simple solutions such as altering the shape or introducing aerodynamic devices such as wings, automotive engineers over the years have come up with some fascinating, and sometimes over-the-top solutions to optimize their car's aerodynamics and achieve lower (Cd) values. The latest example is Porsche, who is looking at introducing vibrations for their EVs to “slice” through the air more efficiently.
“We are examining whether it is possible to reduce the Cd value at certain points in the car body by systematically introducing vibrations,” said Professor Andreas Wagner, the chair of the automotive engineering program at the University of Stuttgart. “If you introduce a defined pulse into the flow around the car using speakers, its separation behavior can be influenced”.
The technology though is very much in its infancy stage. As much as Porsche wants to utilize vibration to alter vehicle aerodynamics, they are still weighing its impact on a car's NVH level (noise, vibration, and harshness). “For example, we have to make sure passengers don’t hear buzzing or humming,” said Wagner. “There is still a lot to do before mass production”.
As we all know, electric vehicles are very smooth since electric motors do not have reciprocating motion like piston engines, and thus, do not produce vibrations. So in case you get to ride in an electric Porsche that vibrates, it's not because it has an internal combustion engine. But instead, it's there to help the car go faster and travel longer distances. Think it makes sense? Let us know in the comments.