tesla-fan-car-1Coincidence? Maybe. The fan system could help the Roadster fulfill some of its wildest promises.Tesla patented a fan system to increase an EV's downforce.It comes two weeks before the event revealing the Tesla Roadster.It isn't clear whether this is going into a production car, but it could help the Roadster fulfill some of its wildest promises.With the Tesla Roadster event just a couple of weeks away, the automaker has patented a design for a car that uses fans to improve downforce and reduce drag. Coincidence? It very well could be. Car companies patent things all the time, and it doesn't mean these features are actually going into production.Or these fans are key to Tesla hitting some of the Roadster's moonshot targets, like Elon Musk's claim of zero to 60 mph under a second. To be sure, the diagram included in the patent filing looks like a Model S. But Tesla isn't making that anymore, anyway.The patent describes an "electric fan car" that would have four electric fans mounted to the rear diffuser of an EV, to help with downforce and aerodynamics. Think of Gordon Murray's GMA T.50, or the McMurtry Speirling, just without the cool turbine-looking fan at the back. Instead, the patent drawing looks more like a car with a bunch of PC case fans underneath its taillights.The idea behind a fan car isn't to add propulsion, but rather to smooth out turbulent airflow underneath a car and effectively suck it down toward the pavement. By creating an air inlet underneath the car, into the rear diffuser, you allow airflow to push the rear of the car down, creating downforce while reducing aerodynamic drag.tesla-fan-car-2The problem with that is the airflow can get stuck as it rises up into the diffuser, and that defeats the whole point. Having an electric fan pull that turbulent air through the diffuser smooths all of that out and creates a sort of vacuum underneath the car, pulling it down toward the ground. In theory, that would help a car corner better and hit higher speeds without catching air.EVs don't typically have a ton of problem with traction, since they're so heavy and electric motors are great at metering out power, but this could also help improve aerodynamic drag and make the car slipperier through the air.Here's how it's described in the patent filing:An electric vehicle comprising a ducted fan system configured to increase downforce and reduce drag. The ducted fan system can include a diffuser extending from an input on an underbody of the vehicle and to an outlet on a rear side of the vehicle. The ducted fan system can be connected to a high voltage battery and a control system of the electric vehicle. The electric vehicle can further include a second diffuser to enhance downforce.If you look at the patent drawings, this really only affects the very rear end of the car, as the diffuser inlet is behind the rear wheel. So it seems to be targeted at keeping the rear down. It isn't the first fan-car-related patent Tesla has filed. Last year, the company patented a design for a system of skirts and electric fans that suck a car to the ground.There's no word on whether Tesla will actually implement such a technology on a road car, or which car would get fans if it did. But there seems to be one obvious candidate: the Roadster. Tesla execs have described it as the swan song for human-driven Teslas. Lars Moravy, the company's top engineer, said it would be the "last, best driver's car" Tesla ever makes.We may not have to wait too long to learn if these fans are just a neat idea or are bound for a production vehicle. Tesla plans to show off the Roadster (finally) on October 15.Check Out These Related StoriesThis $1.4 Million EV Has A Weird Trick To Hit 60 MPH In 1.55 SecondsThe Production McMurtry Speirling Will Not Look Like The PrototypesGeneral Motors Just Took A Big Step Towards Its Next-Gen EV BatteryVolkswagen's European Battery Push Has A New Chinese Partner
