Autofield Blog

When the Rain Comes. . .


By:

8. April 2014

If past is prelude, then we can pretty much look forward to the Polar Vortex being replaced by the Tropical Monsoon or something along those lines, meaning April Showers 2.0.

Which leads to an explanation of how automatic windshield wipers work on the remarkably popular Buick Encore small crossover.

2014 Buick Encore with Rainsense GM’s rain sensor technology global design engineer Matt Piazza

One might wonder whether there is a sensor that detects moisture which leads to the activation of the wipers. And one would be wrong.

Actually, the rain sensor is actually a light sensor that’s located behind the rearview mirror, mounted on the windshield at a 25- to 30-degree angle.

The sensor, about the size of a wristwatch (or, about 2 in. in diameter, as wristwatches are rapidly giving way to smartphones and other non-wrist-based devices that offer time among other functions), actually uses infrared light beams to detect water droplets on the windshield. The sensor takes measurements at a rate of every 40 milliseconds.

Not only does the sensor detect the droplet, but size and frequency, as well, thereby providing data that is then used to trigger the wipers.

According to Matt Piazza, General Motors global design engineer for rain sensor technology, “Each vehicle is unique and there are a lot of factors like windshield pitch, rain intensity, vehicle speed, and light conditions that all have to be accounted for and validated.”

The “Rainsense” system for the Encore was engineered by GM with sensor supplier Hella Electronics.

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