Rain-sensing Wipers

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Rain-sensing Wipers
In the past, automakers have tried to either eliminate the wipers or to control their speed automatically. Some of the schemes involved detecting the vibrations caused by individual raindrops hitting the windshield, applying special coatings that did not allow drops to form, or even ultrasonically vibrating the windshield 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 cars that actually does a good job of detecting the amount of water on the windshield and controlling the wipers. One such system is made by TRW Inc., here is a PDF describing their rain sensor system. TRW Inc. uses optical sensors to detect the moisture. The sensor is mounted in contact with the inside of the windshield, near the rearview mirror.

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 it back 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 wipes. It can operate the wipers at any speed. The system adjusts the speed as often as necessary to match with the rate of moisture accumulation.

The TRW system, which is found on many General Motors cars, including all Cadillac models, can also be overridden or turned off so the car can be washed.

mqh0386

好的，我将以汽车工程师的身份回复帖子。关于感应雨刷（Rain-sensing Wipers）：

感应雨刷系统是一种智能雨刷系统，其核心技术在于能够感知雨滴并自动调整雨刷的工作状态。此系统通过先进的传感器技术来检测雨滴的存在和强度，并据此自动调整雨刷的摆动频率，确保在雨天驾驶时，驾驶者的视线始终保持清晰。这种智能化设计不仅提升了驾驶的便捷性和安全性，也大大提升了雨天驾驶的舒适体验。目前，感应雨刷系统已成为许多新款车辆的标准配置。