CO2 Vehicle Air Conditioning Maintenance for Stable Measurement

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Solution Overview

Problem

The high pressures in carbon dioxide air conditioning systems, typically ranging from 130 to 170 bar, pose a challenge for measuring the amount of carbon dioxide discharged during maintenance, as traditional measuring devices are unsuitable, and uncontrolled pressure reduction can lead to dry ice formation, obstructing discharge and invalidating measurements.

Innovation Solution

A maintenance apparatus equipped with a double-stage pressure and flow rate reducing device, which stabilizes the pressure and flow rate of carbon dioxide to safer levels (around 10-15 Bar and 62 litres/minute), and an electronic measuring apparatus to accurately measure the discharged carbon dioxide, along with an oil separator and heating means to prevent dry ice formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional measuring devices are used to measure carbon dioxide discharge, then the measurement can be performed with simple equipment, but the devices are unsuitable due to extremely high pressures (130-170 bar)

Engineering Contradiction:
Improvecarbon dioxide discharge measurementVSAvoidmeasurement reliability under high pressure
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A pressure reducing device is introduced as an intermediary component between the high-pressure carbon dioxide system and the measuring device. This mediator reduces the extreme pressure (130-170 bar) to a manageable level, enabling accurate measurement while protecting the measuring equipment from damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The pressure parameter of the carbon dioxide is changed from an extreme state (130-170 bar) to a moderate state suitable for measurement. By transforming the physical condition of the gas, the system becomes compatible with standard measuring devices while maintaining measurement accuracy.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If uncontrolled pressure reduction is applied during discharge, then the discharge process is simplified, but dry ice formation occurs causing obstructions and invalidating measurements

Engineering Contradiction:
Improvedischarge operationVSAvoiddry ice formation and obstruction
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Heating means are applied in advance to the pressure reducing device or discharge line to prevent the formation of dry ice. By applying heat before the pressure reduction occurs, the system counteracts the cooling effect that would otherwise cause carbon dioxide to freeze and obstruct the discharge path.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The temperature parameter is controlled during the pressure reduction process to prevent phase change. By maintaining the temperature above the sublimation point of carbon dioxide, the gas remains in a measurable state rather than converting to solid dry ice that would block the system.

Inventive Principle:
Principle #35Parameter changes

3Speed

If quick and uncontrolled pressure reduction is applied during discharge, then the discharge speed is increased, but the quick pressure reduction causes dry ice formation that prevents discharge and invalidates measurement

Engineering Contradiction:
Improvedischarge speedVSAvoiddischarge reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The pressure reduction process is divided into multiple stages rather than a single uncontrolled step. The double-stage pressure reducing device progressively reduces pressure, allowing the system to maintain control over the discharge speed while preventing the rapid expansion that causes freezing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rate of pressure change is controlled to balance discharge speed with temperature maintenance. By regulating the pressure reduction rate, the system achieves sufficiently fast discharge while preventing the adiabatic cooling that would lead to dry ice formation and discharge failure.

Inventive Principle:
Principle #35Parameter changes

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 apparatus achieves precise measurement of carbon dioxide discharge, prevents dry ice formation, and ensures reliable operation by stabilizing pressure and flow rates, allowing for accurate diagnosis of system faults and efficient discharge.

Implementation Method 1

a first pressure and flow rate reducing device, arranged along said discharging duct, and structured so as to reduce said first pressure and first flow rate of said flow of carbon dioxide to a second predetermined pressure and to a second predetermined flow rate

Methodology Applied
Scientific EffectPressure reduction: Depressurisation

Implementation Method 2

heating means to prevent dry ice formation

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

an electronic measuring apparatus to accurately measure the discharged carbon dioxide

Methodology Applied
Scientific EffectGas detection:

Data Source

PatentEP3449195B1Apparatus for maintaining a motor vehicle air conditioning system provided with carbon dioxide and operating method thereof
Publication Date: 2019.09.11 TEXA SPA
  • EP3449195B1 patent drawingFigure 1
  • EP3449195B1 patent drawingFigure 2
  • EP3449195B1 patent drawingFigure 3

AI summary

Maintenance apparatus (1) of an air conditioning system (2) mounted on a motor vehicle (3). The maintenance apparatus (1) comprises : two external ducts (8), a discharging circuit (15), which is connected to the ducts (8) to receive the carbon dioxide contained in the air conditioning system (2) at a first pressure (P1) and a first flow rate (Q1) and is structured so as to discharge the carbon dioxide received into the environment, a measuring apparatus (22), which is configured so as to measure the amount of carbon dioxide that passes through the discharging circuit (15), and a pressure and flow rate reducing device (21), which is structured so as to reduce the first pressure (P1) and the first flow rate (Q1) of the carbon dioxide to the be measured to a second predetermined pressure (P2) and to a second predetermined flow rate (Q2), respectively.