Coolant Transfer Through Active HP-LP Branches in Vehicle A/C Reloading

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Solution Overview

Problem

Air conditioning systems in vehicles require frequent coolant fluid reloading due to leakage, and existing methods are inefficient, especially in maintaining high pressure during reloading, which can lead to overheating and slow recovery processes.

Innovation Solution

The method involves transferring coolant fluid from a loading unit to an air conditioning system while maintaining both high and low pressure branches active, eliminating the need for a vacuum phase and utilizing a compressor to ensure efficient reloading without overheating, allowing for continuous recovery and reloading even in partly filled systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the low pressure branch is closed during coolant transfer, then high pressure can be maintained during reloading, but the recovery process becomes slower and overheating occurs

Engineering Contradiction:
Improvehigh pressure during reloadingVSAvoidrecovery speed
Core Design Contradiction:
Stress or pressureVSProductivity

Solution Approach 1:

The patent applies the principle of continuity of useful action by keeping the low pressure branch open during coolant transfer, allowing the recovery process to continue uninterrupted. The compressor simultaneously performs both reloading (through the high pressure branch) and recovery (through the low pressure branch), eliminating idle time and maintaining continuous productive action throughout the process.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent applies preliminary action by pre-cooling the coolant in the tank using the evaporator before transfer. This preliminary cooling action prepares the coolant for efficient transfer and prevents overheating during the reloading process, addressing the thermal management issue before it arises during the main operation.

Inventive Principle:
Principle #10Preliminary action

2Temperature

If a heating bundle is used to support the coolant tank, then the tank can be heated, but the vacuum phase duration increases significantly

Engineering Contradiction:
Improvecoolant tank temperatureVSAvoidvacuum phase duration
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The patent inverts the conventional approach by using a cooling mechanism (evaporator) instead of heating (heating bundle). The evaporator actively cools the coolant in the tank during the vacuum phase, reversing the thermal action and enabling faster phase transition and shorter vacuum duration while achieving the desired temperature control.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent utilizes phase transitions by employing the evaporator to cool the coolant, promoting phase change from liquid to vapor more efficiently. This accelerates the vacuum phase process by facilitating faster evaporation and pressure equalization, thereby reducing the overall duration of the vacuum phase.

Inventive Principle:
Principle #36Phase transitions

3Productivity

If the low pressure branch is kept open during coolant transfer, then recovery speed increases, but high pressure maintenance becomes difficult

Engineering Contradiction:
Improverecovery speedVSAvoidhigh pressure during reloading
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The patent applies segmentation by dividing the coolant transfer process into two independent parallel pathways: the high pressure branch for reloading and the low pressure branch for recovery. This segmentation allows each branch to operate independently with its own pressure regime, enabling the compressor to maintain high pressure in the reloading path while simultaneously recovering coolant through the low pressure path without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies multi-functionality by enabling the compressor to perform dual functions simultaneously: compressing coolant for reloading through the high pressure branch and creating vacuum for recovery through the low pressure branch. This universal operation of the compressor resolves the apparent contradiction by making a single component capable of handling both pressure requirements concurrently.

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

This approach ensures complete and automatic reloading at speeds comparable to a liquid pump, facilitating the process by maintaining a positive coolant balance and reducing the duration of the vacuum phase, thus enhancing the efficiency and speed of the coolant transfer.

Implementation Method 1

the compressor suctions and compresses the coolant, modifying its state and the temperature (from low pressure and low temperature to high pressure and high temperature)

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

the condenser transfers heat to the external air and condenses the coolant, which thus passes from the gaseous state to the liquid state

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

the condenser transfers heat to the external air and condenses the coolant, which thus passes from the gaseous state to the liquid state

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

the coolant then reaches the expansion valve, where it is subjected to a drastic pressure and temperature drop

Methodology Applied
Scientific EffectPressure drop: Pressure Drop

Implementation Method 5

in the evaporator, the coolant once again changes its state, passing from liquid to gaseous. It absorbs heat and lowers the temperature of the air introduced into the cabin

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3121039B1Method for transferring coolant from a loading unit to an air conditioning system
Publication Date: 2019.03.06 MAHLE AFTERMARKET ITAL SPA
  • EP3121039B1 patent drawingFigure 1
  • EP3121039B1 patent drawingFigure 2

AI summary

Method for transferring coolant fluid from a loading unit/station (20) to an air conditioning system (10), by means of at least one high pressure HP valve (7) and duct (15), for the introduction of liquid coolant, and at least one low pressure LP valve (8) and duct (17), for the suction and the recovery of the coolant-vapour in the system (10). It is provided for executing the step of transferring the fluid also maintaining the low pressure circuit branch (17) open/active, through relative LP valve. Part of the coolant loaded during said transfer step passes through a valve for the expansion of the system and it is suctioned, as vapour, by the station through LP: the net amount that enters into the system is always positive given that there is more loaded coolant with respect to the suctioned coolant.