Vehicular Air-Conditioning Case Drainage Design

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Solution Overview

Problem

Conventional vehicular air-conditioning units face issues with drainage, as condensed water from the evaporator accumulates in the air-conditioning case and fails to drain properly, leading to potential leaks and reduced efficiency.

Innovation Solution

The air-conditioning case is designed with a drainage hole located near one end of the accommodation bottom portion, which is inclined to collect condensed water, and a communication slit in the bottom portion rib to guide water from the downstream space into the drainage hole, enhancing drainage performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the air-conditioning case stores condensed water to prevent leaking from fitting portions, then water leakage prevention is improved, but drainage performance deteriorates because water accumulates in the downstream space and cannot be drained

Engineering Contradiction:

Improvewater leakage preventionVSAvoiddrainage performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The air-conditioning case is divided into multiple spaces: a water storage space for storing condensed water and a downstream space for air flow. The bottom portion rib with communication slit separates these spaces while allowing controlled water transfer. This segmentation allows the case to both store water for leakage prevention and enable drainage from the downstream space through the communication slit to the drainage hole.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bottom portion rib acts as an intermediary structure between the water storage space and downstream space. It includes a communication slit that selectively allows water to pass from the downstream space to the water storage space while maintaining structural integrity and preventing uncontrolled leakage. This intermediary structure resolves the contradiction by enabling both water storage and drainage functions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If multiple casing parts are integrated with fitting portions near the lower portion of the evaporator to make the unit small and inexpensive, then manufacturing cost and size are reduced, but water leakage risk increases at the fitting portions

Engineering Contradiction:

Improvemanufacturing cost and sizeVSAvoidfitting portion leakage resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The drainage function is extracted from the fitting portions and relocated to the bottom portion of the air-conditioning case. By providing a dedicated drainage hole and water storage space at the bottom, the system removes the drainage burden from the vulnerable fitting portions, allowing them to focus on their primary function of structural assembly while the bottom structure handles water management.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The water storage space acts as a cushioning buffer that collects condensed water before it can reach the fitting portions. This prior cushioning prevents water from accumulating at the fitting portions, thereby protecting them from leakage even though they are located near the lower portion of the evaporator.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If the accommodation bottom portion has a horizontal bottom surface, then manufacturing is simpler, but condensed water does not collect effectively at the drainage hole

Engineering Contradiction:

Improvebottom surface fabricationVSAvoidwater collection efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The bottom surface of the accommodation bottom portion is designed with an asymmetric inclination rather than being horizontal. This asymmetric design causes condensed water to naturally flow toward the drainage hole located at the lower end, improving water collection efficiency while maintaining relatively simple manufacturing processes.

Inventive Principle:

Principle #4Asymmetry

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

This design effectively drains water from the downstream space, preventing leaks and maintaining the storage capacity for condensed water, thus improving the overall drainage efficiency and reducing the risk of water adhesion and bad smells.

Implementation Method 1

At least a part of the bottom surface is inclined with respect to a horizontal line to collect the condensed water entering the bottom portion space to the drainage hole

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS11142043B2Vehicular air-conditioning unit

Publication Date: 2021.10.12 DENSO CORP

AI summary

An air-conditioning case of a vehicular air-conditioning unit has a cooler accommodation portion defining a cooler accommodation space in which a cooler is accommodated, and a downstream portion defining a downstream space. The cooler accommodation portion includes an accommodation bottom portion defining a bottom portion space. The accommodation bottom portion includes a drainage hole through which condensed water is drained, and the drainage hole is located closer to one end of the accommodation bottom portion than to another end in a longitudinal direction of a lower end of the cooler. A bottom surface of the accommodation bottom portion is inclined with respect to a horizontal line. The air-conditioning case includes a bottom portion rib. The bottom portion rib includes a communication slit. The communication slit is located closer to the one end than to the other end in the longitudinal direction.