Vehicle Headlamp PCM Moisture Prevention

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Solution Overview

Problem

Existing vehicle head lamp designs face issues with moisture generation due to temperature differences, requiring additional devices for air circulation, which can introduce dust and increase costs, and existing solutions like moisture absorbents lose effectiveness when saturated or hydrophilic coatings become costly and inefficient with excessive moisture.

Innovation Solution

A phase change material (PCM) unit is integrated into the head lamp housing, which sprays refrigerant gas to prevent moisture formation by lowering the dew point temperature, using a case with a valve system to control the PCM discharge and maintain air-tightness, reducing moisture generation through controlled refrigerant gas distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If natural convection is used to move internal air for moisture evaporation, then energy consumption is reduced, but moisture removal efficiency is insufficient requiring additional devices

Engineering Contradiction:

Improveenergy consumptionVSAvoidmoisture removal efficiency

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent utilizes phase transition of phase change material (PCM) from solid to liquid state to absorb heat and lower the temperature of the lens surface, preventing moisture condensation. This thermodynamic approach replaces the need for mechanical air circulation devices while maintaining effective moisture control.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The PCM acts as an intermediary substance between the heat source and the lens surface, mediating heat transfer to prevent moisture generation without requiring direct air movement or additional active devices.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If external air is introduced into the head lamp for moisture removal, then moisture can be evacuated, but foreign materials such as dust are introduced deteriorating irradiation capability

Engineering Contradiction:

Improvemoisture evacuation capabilityVSAvoiddust contamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of temperature difference that causes moisture condensation into a beneficial effect by using PCM to actively control temperature and prevent condensation, eliminating the need for air exchange that would introduce dust.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The head lamp housing maintains a sealed inert environment, preventing both moisture accumulation and dust contamination by using thermal control rather than air exchange to manage internal atmosphere.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Productivity

If moisture absorbent is used in the head lamp housing, then moisture can be absorbed, but the moisture removing function is lost when the moisture absorbent becomes saturated

Engineering Contradiction:

Improvemoisture absorption capabilityVSAvoidlong-term effectiveness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The PCM undergoes reversible phase transitions between solid and liquid states, allowing it to continuously absorb and release heat over extended periods without saturation, providing reliable long-term moisture prevention.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The PCM system is self-regulating, automatically absorbing heat when temperature rises and releasing it when temperature drops, maintaining continuous effectiveness without external intervention or replacement.

Inventive Principle:

Principle #25Self-service

4Object-affected harmful factors

If hydrophilic coating is applied to the head lamp lens, then moisture visibility is reduced, but cost increases and hydrophilic capability is lost with excessive moisture

Engineering Contradiction:

Improvemoisture visibilityVSAvoidmanufacturing cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent addresses the root cause of moisture generation through thermal control rather than treating the symptom visually, eliminating the need for costly hydrophilic coatings while preventing both visible and excessive moisture accumulation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The PCM prevents moisture condensation before it occurs by controlling temperature, rather than treating moisture after it forms, eliminating the need for subsequent coating applications or moisture management systems.

Inventive Principle:

Principle #10Preliminary action

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

Effectively suppresses moisture generation by lowering the dew point temperature by 3 to 5° C, improving driving conditions and reducing costs by eliminating the need for additional devices and maintaining effectiveness without saturation issues.

Implementation Method 1

a phase change material (PCM) unit mounted in a housing of the vehicle head lamp... the PCM unit sprays gaseous phase change material (PCM) to an inner portion of the head lamp

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

an elastic member positioned on an upper surface of the plate and elastically biasing the plate toward the through-hole

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8827522B2Moisture generation preventing structure of vehicle head lamp

Publication Date: 2014.09.09 HYUNDAI MOTOR CO LTD

AI summary

A moisture generation preventing apparatus of a vehicle head lamp, may include a phase change material (PCM) unit mounted in a housing of the vehicle head lamp having a lens mounted at a front end portion of the housing to prevent moisture from being generated in the lens when an internal temperature of the head lamp drops below a predetermined degree, wherein the PCM unit sprays gaseous phase change material (PCM) to an inner portion of the head lamp.