Vehicle Antifogging Coating with Boundary Layer Humidity Control

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Solution Overview

Problem

Existing vehicle antifogging systems with water-absorptive coatings operate unnecessarily in low humidity environments, leading to energy loss, and fail to prevent fogging in situations with sudden humidity increases when water absorption is below a predetermined threshold.

Innovation Solution

A vehicle antifogging system that includes a water-absorptive coating on the window, a humidity detector in the temperature boundary layer, and a controller that operates a dryer only when humidity reaches a predetermined threshold, reducing unnecessary operations and improving visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the defroster operates to defog the window by vaporizing water adhering to the internal surface, then the window fogging is prevented, but the temperature in the vehicle cabin decreases and thermal load increases

Engineering Contradiction:

Improvewindow defogging effectivenessVSAvoidthermal load

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by providing a water-absorptive coating on the window surface that proactively absorbs water vapor from the air before it can condense into droplets that cause fogging. This preventive approach eliminates the need for reactive defogging operations, thereby avoiding the thermal load associated with operating the defroster while maintaining clear visibility

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a water-absorptive coating is provided on the window to prevent fogging, then the operation frequency of the defroster is reduced, but when the coating reaches saturated water absorption volume, water droplets form on the surface

Engineering Contradiction:

Improveantifogging performanceVSAvoidwater absorption capacity

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback by incorporating a humidity sensor that continuously monitors the humidity level in the vehicle cabin and a controller that activates the defroster when the humidity exceeds a predetermined threshold. This feedback mechanism ensures that the defroster operates only when necessary to maintain the water-absorptive coating below its saturation point, preventing water droplet formation while minimizing unnecessary energy consumption

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies parameter changes by using the humidity sensor to detect changes in cabin humidity levels and dynamically adjusting the defroster operation based on these parameters. The controller compares the detected humidity against a threshold parameter and activates the defroster only when the parameter exceeds the threshold, optimizing both antifogging performance and energy efficiency

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the defroster operates whenever water quantity in the coating reaches a predetermined value, then the water absorptive capacity is recovered, but the defroster operates unnecessarily in low humidity environments causing energy loss

Engineering Contradiction:

Improvecoating water absorptive capacityVSAvoidenergy loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements feedback by using a humidity sensor to continuously monitor the actual humidity level in the vehicle cabin and a controller that activates the defroster only when the humidity exceeds a predetermined threshold. This feedback mechanism prevents unnecessary defroster operation in low humidity environments while ensuring the coating maintains its water absorptive capacity, thereby reducing energy loss without compromising antifogging performance

Inventive Principle:

Principle #23Feedback

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

The system effectively reduces energy loss and improves fuel economy by minimizing the operation frequency and time of the defroster while ensuring effective prevention of fogging, even in varying humidity conditions.

Implementation Method 1

an antifogging coating provided on a surface of the window facing the vehicle cabin, and configured to absorb water adhering to a surface the antifogging coating into the antifogging coating

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

a dryer configured to vaporize the water absorbed in the antifogging coating

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

a humidity detector configured to detect a humidity in a temperature boundary layer formed along a surface of the antifogging coating facing the vehicle cabin

Methodology Applied

Scientific EffectHumidity detection: Hygrometer

Data Source

PatentUS10525797B2Vehicle antifogging system

Publication Date: 2020.01.07 MAZDA MOTOR CORP

AI summary

An antifogging system of a vehicle includes a windshield provided between a space inside a vehicle cabin and a space outside the vehicle cabin, an antifogging coating provided on a surface of the windshield facing the vehicle cabin and configured to absorb water adhering to a surface the coating into the coating, an air conditioner configured to vaporize water absorbed in the antifogging coating, a humidity sensor configured to detect a humidity in a temperature boundary layer formed along a surface of the antifogging coating facing the vehicle cabin, and a control unit configured to operate the air conditioner when the humidity is equal to or higher than a predetermined threshold.