Will Sound Waves Become the Future Way to Clear a Windshield?
No, really. McLaren is looking to adapt such a system to replace the traditional windshield wiper on their future cars. If it’s proven to be a success, ultrasound-based cleaning could quickly spread industry-wide.
How Do Sound Waves Clean a Windshield?
One or more sonic transducers send ultrasonic waves across the surface of the windshield, turning the glass into a giant shake table. Surface tension between the glass and the debris is reduced while the debris particles themselves are shaken apart. Water and dirt are dispersed and flung off, keeping the view clear.
McLaren says their system will use at least one ultrasonic transducer tuned to 30 kHz, but they’re not the only ones working on ultrasonic windshields: UK-based Echovista Systems Ltd. has patents for a similar system primarily using 2 Mhz pulses with the ability to change wavelengths to target debris of varying sizes. Other systems have been proposed with multiple transducers that could triangulate pulses aimed at specific debris particles, and even the heat from the vibrations could be used against surface ice and fogging.
What’s the point?
Obviously, such a system would mean zero maintenance: no more changing wipers or squeaky blades across the windshield, and no need for windshield washer fluid since the vibrations are effective on both dry and wet debris. The ultrasonic waves clean the entire surface almost instantaneously, increasing safety.
However, the main reason McLaren is interested in the technology is aerodynamics. A wiper’s boxy profile becomes a wall at high speeds, increasing drag and requiring significant air flow modification to prevent lift from pulling the wipers off the windscreen while in use.
When will they reach production?
Fighter jets already use a system similar to what McLaren and Echovista are proposing; it’s just a matter of packaging the system in a way that meets the space and cost requirements of a car.
Current safety regulations require traditional wipers, and those aren’t likely to change until McLaren can prove the technology’s reliability. In the meantime, the company will be rolling out the system on their race cars. Echovista has already done a considerable amount of research, but they will need to partner with a manufacturer to turn their work into a commercial product. If McLaren’s system proves to be a success on the track, expect an automaker to purchase Echostar, so they can get a head start on the technology.