Windshield wiper technology has been pretty stagnant since Mary Anderson came up with, basically, the swiping blades we recognise today. Sure, we have intermittent settings and rain-sensing and Mercedes had that bonkers Monoblade, but the concept hasn’t changed much since 1903. According to a patent filed in March and published just five days ago though, the reign of the single-pivot wiper may be in trouble, as Tesla has a new idea. A wiper idea.
Mary Anderson’s 1903 patent shows a wiper that sweeps an arc-shaped area of a window clean of water droplets as the wiper arm pivots from a fixed point.
This fundamental design has remained the same since this time, with effectively all automotive wiper systems employing one or more wipers that pivot at their base, driven by a simple electric motor and some hardware to translate the continual spinning of the motor shaft into a back-and-forth reciprocating motion.
We’ve all seen windshield wipers, we know what the deal is.
Since we’re all so familiar, we also know that the arc-like areas the wipers clean usually leave unswept areas of a windshield; Tesla’s patent could solve this and provide more coverage.
Essentially, Tesla’s patent is describing a vertical wiper arm that moves horizontally across a windshield, providing almost total wiping coverage.
To accomplish this, instead of a conventional, spinning-shaft electric motor, this system would use a linear actuator, though I suspect you could get basically the same effect with a conventional motor and a belt-drive, which could even provide a bit of vertical motion shifting as the wiper assembly travelled on the upper and lower parts of the belt.
That doesn’t matter, because that’s not how Tesla’s doing it. Tesla’s being way fancier, as you can read for yourself, from its patent description:
“The disclosed electromagnetic wiper system may further include a linear actuator that may include a guide rail and an electromagnetic moving block. The guide rail may include a plurality of permanent magnet bars that may be disposed horizontally along a curvature of the windshield of the vehicle.
The electromagnetic moving block may act as an electromagnetic train, and may include a plurality of perforations and at least an electromagnetic coil that surrounds the plurality of perforations in the electromagnetic moving block. The disclosed electromagnetic wiper system may further include control circuitry that controls the linear motion of the electromagnetic moving block through the plurality of permanent magnet bars.
The linear motion of the electromagnetic moving block through the plurality of permanent magnet bars may be controlled to steer the wiper arm that may be coupled to the electromagnetic moving block, back and forth across the entire length of the windshield to wipe a defined region, for example, the entire transparent area (i.e., near cent per cent area) of the windshield.
The plurality of permanent magnet bars may pass through the plurality of perforations surrounded by the electromagnetic coil in the electromagnetic moving block. This may result in minimal friction during the linear motion of the electromagnetic moving block.
Alternatively stated, the disclosed electromagnetic wiper system may utilise the current carrying electromagnetic coil in the electromagnetic moving block to generate a magnetic induction-based electrodynamic force to steer the wiper arm, and is thereby able to efficiently and effectively minimise friction that otherwise may exist between the moving elements of a conventional wiper system.”
Whoa. Got all that? Basically, this is just an alternate kind of electric motor, one that moves linearly instead of rotationally.
Tesla feels such a setup would prove more energy-efficient as well:
In some conventional wiper systems, electrical motors are used to move one or more wiper blades to clean a windshield of a vehicle. The electrical motors include many mechanical components, such as gears and bearings, to slide the wiper blades. However, such sliding motion of the mechanical components creates significant friction resulting in the need for additional power to be supplied by the in-vehicle battery, which decreases vehicle range.
Further, the gears and bearings of the conventional systems are susceptible to rust and wear, which may lead to poor and in-efficient cleaning of windshields. Such corrosion and system deterioration is especially true in geographical areas subject to harsh weather conditions, like significant rainfall or snowfall.
When these systems corrode accident risk increases, and may result in driver-assist or autonomous-driving functionality being rendered inoperable.
The main argument here seems to be frictional losses drawing more electrical power, though the system Tesla describes would require some sort of at least partially-open linear track for the wiper arm to travel over, which would also be vulnerable to debris and various grimy build-ups of gunk that could impede wiper progress, increase friction, and cause more electrical demand as well, I’d think.
The system is certainly cool, and would absolutely have a wow factor that, if I’m a bit cynical but honest, is likely the real motivation behind this wiper system.
Sure, this linear system would clear more windshield area, but it’s not like most modern systems aren’t already quite effective; perhaps there’s thinking that future autonomous cameras and sensors may need more comprehensive rain-clearing?
Novel wiper systems like these are very cool, but they have some less sexy disadvantages. Part of the reason Mercedes-Benz abandoned their definitely superior Monoblade articulated wiper system was that they could no longer rely on standard supplier parts, and that makes everything more expensive, and getting consumables — like wiper blades — was harder and more expensive for owners, too.
There’s added complexity and cost to build and a lot of other reasons why an improved wiper system — unless it somehow provided dramatically better results — likely just doesn’t make sense.
Unless it looks really cool in action, though — that kind of irrational shit is what really sells cars, after all, and it’s also the sort of thing Tesla loves. With that in mind, I think this has a decent chance of becoming real.