Vehicle A/C Service Flushing for Refrigerant Cross-Contamination

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Solution Overview

Problem

Existing service devices for vehicle air conditioning systems face challenges in handling sensitive refrigerants and compressor oils, as newer refrigerants and compressor oils react adversely to mixing with residues from previous service activities, leading to contamination and loss of properties such as low electrical conductivity.

Innovation Solution

A service device with an evacuable detergent tank connected to the service connection and refrigerant supply under increased pressure, allowing for thorough cleaning of residues and enabling the use of different refrigerant/compressor oil mixtures without contamination, with the detergent tank capable of reusing coolant after cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a service device is used to handle refrigerant/compressor oil mixtures, then maintenance and refilling operations can be performed, but residues from previous service activities contaminate subsequent operations, causing loss of properties such as electrical conductivity

Engineering Contradiction:
Improveservice operation efficiencyVSAvoidrefrigerant/compressor oil compatibility
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a self-cleaning function that performs preliminary cleaning action between service operations. The cleaning process is automatically initiated after each service operation completes, removing residues before the next operation begins. This preliminary action prevents contamination of subsequent refrigerant/compressor oil mixtures, maintaining their electrical conductivity and compatibility properties.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The service device performs self-cleaning using its own internal resources. The cleaning process utilizes the vacuum pump, separator, and existing fluid pathways to remove residues from the refrigerant circuit system without requiring external cleaning equipment. The system uses its own vacuum capability to suction cleaning fluid through the circuit, achieving self-maintenance and eliminating downtime for external servicing.

Inventive Principle:
Principle #25Self-service

2Reliability

If the service device cleanses the refrigerant circuit system, then contamination is removed, but additional time is required for the cleaning process

Engineering Contradiction:
Improvecontamination-free operationVSAvoidcleaning cycle duration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the cleaning function with the existing service operation sequence. The self-cleaning process is integrated into the normal workflow by utilizing the same fluid pathways, vacuum pump, and separator that are already part of the service device. The cleaning fluid is introduced through existing service connections and routed through the same refrigerant circuit system, combining multiple functions into a unified process that minimizes additional time requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cleaning process is designed to be rapid and efficient, rushing through the necessary cleaning steps without unnecessary delays. The vacuum pump creates strong suction to quickly draw cleaning fluid through the circuit system, and the separator rapidly separates and removes residues. The automated control system coordinates valve operations to streamline the cleaning sequence, minimizing the overall cleaning cycle time while ensuring thorough contamination removal.

Inventive Principle:
Principle #21Skipping (Rushing through)

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

The solution effectively cleans the service device of previous refrigerant/compressor oil mixture residues, allowing for contamination-free operation with different refrigerant/compressor oil mixtures, ensuring compatibility and maintaining the properties of the oils and refrigerants.

Implementation Method 1

a vacuum pump (113) for emptying the refrigerant circuit system of the vehicle air conditioning system

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

This separates refrigerant from the extracted mixture by evaporation and supplies it to a refrigerant supply

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

a separator (14')

Methodology Applied
Scientific EffectGravitational separation: Gravitation

Implementation Method 4

A suction pump 12' designed as a refrigerant compressor conveys used refrigerant/compressor oil mixture

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP2665611B1Service device for vehicle air conditioning systems, and method for operating same, in particular for the self-cleaning of same
Publication Date: 2014.10.08 DOMETIC APPLIANCES
  • EP2665611B1 patent drawingFigure 1
  • EP2665611B1 patent drawingFigure 2
  • EP2665611B1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a service device for vehicle air conditioning systems, in particular for the self-cleaning of said device. The service device is equipped with a discharging and a filling device for suctioning the coolant/compressor oil mixture out of the coolant circuit system of a vehicle air conditioning system and for refilling the vehicle air conditioning system with coolant and compressor oil. A vacuum pump (113) is used to completely empty the coolant circuit system of the vehicle air conditioning system and/or the service device, and furthermore the vehicle air conditioning system is refilled with coolant, compressor oil, and optionally an additive using a refilling system (115, 119) with a highly pressurized coolant supply (115). According to the invention, an evacuated or at least partially evacuated flushing agent tank (153) is directly or indirectly connected to at least one of the high-pressure connectors of the service device and/or the downstream pressure tubes and/or the switching valve block via a connecting line; an additional fluid connection to the highly pressurized coolant supply results such that coolant is flushed or flows from the coolant supply into the flushing agent tank; and fluid lines and/or channels containing the coolant/compressor oil mixture from the previous servicing are entirely or partially flushed clear.