Autowiper Controller Condensation Detection
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Solution Overview
Problem
Conventional autowiper controllers frequently wipe away condensation on windshields unnecessarily, as they lack sensitivity to distinguish between raindrops and condensation, leading to bothersome frequent wiping and inefficient operation.
Innovation Solution
An autowiper controller with dual sensitivity rainfall detection, ambient temperature, and windshield surface temperature monitoring to differentiate between raindrops and condensation, adjusting wiper operation accordingly to prevent unnecessary wiping during condensation while ensuring high sensitivity raindrop detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sensitivity detection threshold (1.5% light quantity reduction) is used to detect raindrops, then raindrop detection sensitivity is improved, but condensation is falsely detected as raindrop and causes unnecessary frequent wiper operation
Solution Approach 1:
The system dynamically adjusts the detection threshold based on ambient temperature and windshield surface temperature conditions. When condensation conditions are detected (low temperature differential), a higher threshold is applied to prevent false detection, while under normal conditions the lower threshold enables sensitive raindrop detection.
Solution Approach 2:
The detection parameter (light quantity reduction threshold) is changed based on environmental parameters (temperature differential between ambient air and windshield surface). The system switches between 1.5% threshold for raindrop detection and higher threshold for condensation conditions, optimizing detection accuracy for different scenarios.
2Ease of operation
If low sensitivity detection threshold is used to avoid false detection of condensation, then unnecessary wiper operation is reduced, but actual raindrops may not be detected promptly
Solution Approach 1:
The system dynamically switches between detection modes based on temperature conditions. During condensation-prone conditions (small temperature differential), low sensitivity mode prevents false alarms. During normal conditions (large temperature differential), high sensitivity mode ensures prompt raindrop detection.
Solution Approach 2:
The system uses feedback from temperature sensors to continuously adjust detection sensitivity. The temperature differential information feeds back to the control unit, which adjusts the light quantity threshold accordingly, creating a closed-loop system that adapts to environmental conditions.
3Area of stationary object
If raindrop detecting surface area is kept small to avoid disturbing driver's field of view, then visual obstruction is minimized, but detection coverage is reduced making high sensitivity detection more difficult
Solution Approach 1:
Instead of changing the physical detection surface area, the system changes the detection parameter (light quantity threshold) based on temperature conditions. This allows the small detection surface to achieve high effective sensitivity by adjusting the decision threshold rather than the physical collection area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents unnecessary wiping of condensation while ensuring rapid detection and removal of raindrops, enhancing driver comfort by optimizing wiper control based on environmental conditions.
Implementation Method 1
an infrared light is irradiated from a light emitting device onto the raindrop detecting surface, for example, and a reflected light is received by a light receiving device
Implementation Method 2
a moisture in the air is solidified over an external surface of the cold windshield and thus becomes dewy as a minute waterdrop
Data Source
AI summary
First and second temperature check portions 7 and 8 determine whether an ambient temperature T1 is lower than 20° C. or not, whether an external surface temperature T2 of a windshield S is lower than 25° C. or not and whether a temperature difference (T2−T1) is lower than 20° C. or not, and a weather condition check portion 9 determines whether a condition that condensation occurs over the windshield S is met or not based on results of the checks. A wiper control portion 10 controls a driving operation of a wiper W based on a rainfall state checked by a low sensitivity rainfall check portion 5 when the condition that the condensation occurs is met, and controls the driving operation of the wiper W based on a rainfall state checked by a high sensitivity rainfall check portion 4 when a condition that the condensation does not occur is met.