A drop generator for the evaluation of automotive rain sensors

The sensitivity of rain sensors strongly depends on the type of rain, i.e. the intensity, drop size distribution and impact of wind. We present a performance evaluation system for rain sensors that can simulate a wide variety of rain conditions, ranging from mist to large droplets with diameters of about 4 millimeters at variable intensities. The system is based on aerodynamic drop generation where the drop size is determined by the accumulated volume prior to drop detachment, which can be controlled by the airflow rate.