CO2 A/C Service Pressure Reduction for Accurate Discharge 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 with a double-stage pressure and flow rate reducing device, which stabilizes the pressure and flow rate of carbon dioxide from 150-170 bar to 10-15 bar and 60-70 litres/minute, respectively, and an electronic measuring apparatus to accurately measure the discharged carbon dioxide, while an oil separator and heating means 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 measurement capability is provided, but the devices are unsuitable due to extremely high pressures (130-170 bar)

Engineering Contradiction:

Improvemeasurement capabilityVSAvoidsuitability for high pressure

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The pressure reduction process is divided into two distinct stages: a first pressure reducing device reduces pressure from 130-170 bar to an intermediate level, and a second pressure reducing device further reduces it to 10-15 bar. This segmentation allows each device to operate within suitable pressure ranges, enabling reliable measurement while handling high-pressure carbon dioxide systems.

Inventive Principle:

Principle #1Segmentation

2Speed

If uncontrolled pressure reduction is applied to carbon dioxide, then discharge speed is increased, but dry ice formation occurs causing obstructions and invalidating measurements

Engineering Contradiction:

Improvedischarge speedVSAvoiddry ice formation

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

Heating means are activated before and during the pressure reduction process to preheat the carbon dioxide. This preliminary heating action prevents the temperature from dropping to the point where dry ice would form during the subsequent pressure reduction, thereby avoiding obstructions and measurement invalidation while maintaining discharge speed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The heating means act as an intermediary element between the high-pressure carbon dioxide and the pressure reducing devices. By introducing thermal energy as an intermediate factor, the system controls the temperature profile during pressure reduction, preventing harmful dry ice formation while allowing controlled discharge.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If quick and uncontrolled pressure reduction is performed, then discharge efficiency is improved, but measurement accuracy is invalidated due to dry ice obstructions

Engineering Contradiction:

Improvedischarge efficiencyVSAvoidmeasurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system dynamically balances discharge efficiency and measurement accuracy by using controllable pressure reducing devices and heating means. The pressure reduction is controlled rather than uncontrolled, maintaining sufficient discharge speed while preventing dry ice formation, thus achieving both productivity and measurement precision.

Inventive Principle:

Principle #15Dynamics

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, enhancing measurement accuracy and system stability.

Implementation Method 1

a first pressure reducing device, which reduces a first pressure P1 of a flow of carbon dioxide supplied from the air conditioning system to a second pressure P2

Methodology Applied

Scientific EffectPressure reduction: Pressure Drop

Implementation Method 2

a flow rate reducing device, which reduces the first flow rate Q1 of the flow of carbon dioxide to a second flow rate Q2

Methodology Applied

Scientific EffectFlow rate reduction:

Implementation Method 3

heating means prevent dry ice formation

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 4

an oil separator and heating means prevent dry ice formation

Methodology Applied

Scientific EffectPhase separation:

Data Source

PatentUS11149998B2Apparatus for maintaining a motor vehicle air conditioning system provided with carbon dioxide and operating method thereof

Publication Date: 2021.10.19 TEXA SPA

AI summary

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