Vehicular Air Conditioning Drainage Space Pressure Management

Solution Overview

Problem

Vehicular air conditioning units face issues with drainage, as the pressure difference between the air conditioning case and the outside environment can lead to abnormal noises and increased ventilation loss due to air flowing into or out of the drainage holes, depending on their placement relative to the blower and heat exchanger.

Innovation Solution

The air conditioning case includes a space forming portion that creates a drainage space communicating with both the upstream and downstream sides of the air passage, with a drainage portion for external discharge and communication holes that balance pressure between these areas, reducing the likelihood of air influx or efflux through the drainage holes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If drainage holes are placed in the air conditioning case, then water drainage function is improved, but air flows into or out of the drainage holes due to pressure difference, causing ventilation loss and abnormal noises

Engineering Contradiction:

Improvewater drainage functionVSAvoidventilation loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The drainage space is segmented from the air passage by the space forming portion, creating a separate drainage chamber that communicates with both upstream and downstream sides. This segmentation allows independent pressure management for drainage while maintaining air flow integrity, preventing air leakage through drainage holes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The drainage space acts as an intermediary chamber between the air conditioning case interior and exterior drainage holes. By communicating with both upstream and downstream sides, it serves as a pressure buffer that prevents direct pressure-driven air flow through drainage holes, eliminating abnormal noises and ventilation loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If drainage holes are placed in the air conditioning case, then water drainage function is improved, but abnormal noises occur due to air flowing into or out of the drainage holes

Engineering Contradiction:

Improvewater drainage functionVSAvoidabnormal noises

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The drainage space is segmented from the air passage by the space forming portion, creating a separate drainage chamber that communicates with both upstream and downstream sides. This segmentation allows independent pressure management for drainage while maintaining air flow integrity, preventing air leakage through drainage holes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The drainage space acts as an intermediary chamber between the air conditioning case interior and exterior drainage holes. By communicating with both upstream and downstream sides, it serves as a pressure buffer that prevents direct pressure-driven air flow through drainage holes, eliminating abnormal noises and ventilation loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If a drainage space is created partitioned from the air passage, then air flow interference is reduced, but the structure becomes more complex

Engineering Contradiction:

Improveair flow efficiencyVSAvoidstructure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The space forming portion is integrated into the air conditioning case structure, merging the drainage space formation with the existing case geometry. This integration achieves air passage separation and drainage functionality without adding separate complex components, maintaining structural simplicity while improving air flow efficiency.

Inventive Principle:

Principle #5Merging (Combining)

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 configuration maintains intermediate pressure within the drainage space, minimizing ventilation loss and abnormal noises by preventing air from entering or escaping through the drainage holes, ensuring smooth and efficient water drainage while reducing interference between air and water flows.

Implementation Method 1

a heat exchanger housed inside the air conditioning case, the heat exchanger exchanging heat between a fluid flowing therein and the ventilation air

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a blower disposed on an air flow downstream side of the heat exchanger, the blower generating an air flow that flows toward the passenger compartment

Methodology Applied

Scientific EffectPressure difference driven flow: Pressure Gradient

Data Source

PatentUS11077739B2Vehicular air conditioning unit

Publication Date: 2021.08.03 DENSO CORP

AI summary

In a vehicular air conditioning unit, an air conditioning case includes a space forming portion that forms a drainage space which is partitioned from an air passage. The space forming portion includes a drainage portion that discharges water from inside the air conditioning case to outside of the air conditioning case. Further, the space forming portion includes an upstream side communication portion that communicates the drainage space to an upstream side space on an air flow upstream side of the blower in the air passage. Further, the space forming portion includes a downstream side communication portion that communicates the drainage space to a downstream side space on the air flow downstream side of the blower in the air passage.