HVAC Casing Drain Channel Prevents Condensate Leakage

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Solution Overview

Problem

In HVAC systems, condensed water generated in the fresh-air passage of air conditioning units can leak into the vehicle interior through the communication hole between the fresh-air and recirculation-air passages, even when the door is closed, due to condensation during fresh-air mode operation.

Innovation Solution

The casing design includes a drain channel extending from the passage defining member to a space outside the recirculation-air passage, which directs condensed water away from the communication hole, preventing leakage into the vehicle interior by utilizing a declining surface and groove to guide droplets into the drain channel, ensuring they are discharged before reaching the opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the door closes the communication hole to prevent water leakage, then water leakage is reduced, but condensed water still leaks through the space between the door and edge of the communication hole

Engineering Contradiction:

Improvewater leakage preventionVSAvoidcondensed water leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the harmful condensed water from the fresh-air passage by providing a dedicated drain channel that directs it to the recirculation-air passage, separating the water discharge function from the door's sealing function

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The drain channel acts as an intermediary structure between the fresh-air passage and recirculation-air passage, providing a controlled path for condensed water to flow through rather than leaking through the door gap

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If fresh air is cooled in the fresh-air passage, then cooling performance is improved, but condensed water is generated inside the passage

Engineering Contradiction:

Improvefresh air coolingVSAvoidcondensed water generation

Core Design Contradiction:

TemperatureVSQuantity of substance

Solution Approach 1:

The patent converts the harmful condensed water byproduct of cooling into a manageable flow by designing the drain channel with a declining surface that actively guides the water to the discharge location, turning a problem into a controlled process

Inventive Principle:

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

3Reliability

If the drain channel is extended to discharge condensed water outside the recirculation-air passage, then water discharge effectiveness is improved, but device complexity increases

Engineering Contradiction:

Improvecondensed water dischargeVSAvoidcasing structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the drain channel with the existing casing structure, integrating the water discharge function into the housing rather than adding a separate external drainage system

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The recirculation-air passage serves multiple functions: it acts as both an air circulation path and a drainage channel for condensed water, eliminating the need for a completely separate drainage system

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 prevents the leakage of condensed water into the vehicle interior during both fresh-air and recirculation-air modes by ensuring condensed water is discharged through the drain channel before it can enter the vehicle, maintaining interior dryness and comfort.

Implementation Method 1

The drain channel extends from the passage defining member to a space outside of the recirculation-air passage to discharge condensed water generated in the fresh-air passage

Methodology Applied

Scientific EffectGravity: Gravitation

Implementation Method 2

condensed water generated in the fresh-air passage

Methodology Applied

Scientific EffectCondensation: Condensation

Data Source

PatentUS10569621B2Casing for air conditioning unit

Publication Date: 2020.02.25 DENSO INTERNATIONAL AMERICA INC

AI summary

The present disclosure provides a casing for an air conditioning unit including a main body, a door, a passing defining member, and a drain channel. The main body includes a fresh-air passage and a recirculation-air passage. The recirculation-air passage is positioned below the fresh-air passage. The door selectively opens and closes a communication hole through which the fresh-air passage and the recirculation-air passage are in fluid communication with each other. The passage defining member is disposed upstream of the communication hole and defines a lower side of the fresh-air passage. The drain channel extends from the passage defining member to a space outside of the recirculation-air passage to discharge condensed water generated in the fresh-air passage.