Most Car Windscreen Wipers have a low and a high speed, as well as an intermittent setting. When wipers are on low and high speed, the motor runs continuously but in the intermittent setting, the car windscreen wipers stop momentarily between each wipe.
There are many different kinds of switches for car windscreen wipers, some cars have just one intermittent speed while others have up to 10 discrete settings or sliding scale that can be set for almost any time interval.
However, whichever kind of control your car wipers have, setting them just right can be tricky. Too fast makes the windscreen gets dry and the wipers squeak; too slow will make the wipers move properly but leaving the windscreen wet which can affect or block the driver’s visibility under raindrops.
Compounding this is the fact that the amount of water hitting the windshield changes as your car speeds up and slows down. It can require almost constant attention to keep the car windscreen wipers operating properly that had been a problem expected that automobile makers would resolve.
However, in answer to that, a new wiper had been made to sense and operate automatically without the driver control and that is the Rain-sensing car windscreen wipers.
HOW RAIN-SENSING CAR WINDSCREEN WIPER WORKS
Though in the past, automobile manufacturers tried to either eliminate the car windscreen wipers or to control their speed automatically such was not possible.
Some schemes involved detecting the vibrations caused by individual raindrops hitting the windscreen, applying special coatings that did not allow drops to form, or even ultrasonically vibrating the windscreen to break up the droplets so they don’t need to be wiped at all.
But these systems were plagued by problems and either never made it to production or were quickly axed because they annoyed more drivers than they pleased.
However, a new type of wiper system is starting to appear on modern cars that actually does a good job of detecting the amount of water on the windscreen and controlling the wipers automatically and that had been referred to as the “rain-sensing car windscreen wipers”.
Some of the car windscreen wipers of this category make use of optical sensors to detect the moisture. The sensor is usually mounted in contact with the surface of the windshield near the rear view mirror.
When in operation, the sensor projects infrared light into the windshield at a 45-degree angle. If the glass is dry, most of this light is reflected back into the sensor by the front of the windshield.
If water droplets are on the glass, they reflect the light in different directions, the wetter the glass, the less light makes its back reflection into the sensor.
The electronics and software in the sensor turn on the wipers when the amount of light reflected onto the sensor decreases to a preset level.
The software sets the speed of the wipers based on how fast the moisture builds up between each wipe.
It can operate the car windscreen wipers at any speed and that can be done as often as possible to match with the rate of moisture accumulation.
THE WORKING PRINCIPLE OF THE WASH AND WIPE FUNCTIONS OF CAR WIPERS
In modern automobiles, the activation of car windscreen wiper automatically turns on a screen-washing device.
This device is made up of a plastic reservoir and a motor pump which forces liquid through tubing to two or more adjustable nozzles. These nozzles spray liquid on the windshield to wash it.
The wash and wipe functions are combined and occur simultaneously such that the car windscreen wipers wipe off the fluid along with raindrops, thereby making the windshield clearer and brighter for better visibility.
