Rain Sensor Description and Operation

Description

1. Wiper Control System. When the "AUTO" signal is received from the multifunction switch on the right, the integrated rain sensor detects the amount of precipitation. The sensor is installed inside the upper part of the windshield to control the wiper motor. This system automatically controls the duration and speed of wiper operation according to the measured amount of precipitation, even when the driver does not operate the wiper switch.

   

Functions and Operation Principles

1. 1
   Rainfall Detection. Light (beam) emitted by the LEDs is totally reflected from the outer surface of the windshield and returned to the photodiodes. When water is present on the outer surface of the windshield, the light is optically separated and partially reflected, and the remaining brightness is measured by the photodiodes. Water remaining on the windshield causes the light to not be fully reflected. The loss of brightness due to this indicates how wet the glass surface is.
2. 2
   Dust on the measuring surface and other surfaces in the light path (LED and photodiode surfaces, optical fiber, bracket, and glass surface in the area of the windshield contact) weakens the received light.
3. 3
   Movement of the windshield and bracket
4. 4
   Movement of the bracket due to vibration
5. 5
   Damaged wiper blade

1. 1
   Rain Sensor Operating Condition

   Operation Mode	Operation
   Direct Mode	This is the normal operating condition of the integrated rain sensor when the wiper switch is in the "AUTO" position and the sensor detects a dry windshield. In this condition, the integrated rain sensor determines the wiper operating mode according to the precipitation and its duration.
   Intermittent Mode	The integrated rain sensor activates intermittent mode when wiper operation is performed consecutively more than two times with a pause of 0.5 - 5 seconds.
   Low speed	Wipers operate continuously at low speed
   High speed	Wipers operate continuously at high speed

2. 2
   When ice or foreign material is present in the detection area, the integrated rain sensor cannot correctly recognize the operating conditions.
3. 3
   Rain sensor

   Special Condition	Operation Based on Special Condition Detection
   Hesitation	When the integrated rain sensor detects a high level of water (spray) in automatic or intermittent mode, the system switches from park mode to high speed. Then wiping is performed once at high speed and once more at low speed. If the precipitation condition does not change after wiping, the system returns to the original state (automatic or intermittent).
   Smearing	Smearing is a thin oil film that dries quickly and occurs when a small amount of precipitation is smeared by a dirty or worn wiper blade. The operating signal should not be output when smearing occurs in automatic or intermittent mode.
   Mud	If no change is detected after wiping, the integrated rain sensor determines that the windshield is contaminated. In this condition, the operating signal should not be output. If the windshield becomes clean (for example, by washer fluid), the integrated rain sensor returns to normal condition.
   Washer Fluid	The integrated rain sensor does not respond to washer fluid in washing mode. In other words, the wiping speed does not change even if washer fluid is sprayed (the automatic washer pump operation does not affect the operation of the integrated rain sensor).