CO2 Refrigerant Line With Metal Corrugated Hose and Plastic Jacket
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Solution Overview
Problem
Air conditioning systems in motor vehicles face challenges with carbon dioxide as a refrigerant due to high pressures and vibrations, which render traditional flexible elastomer hoses inadequate, requiring rigid lines that cannot absorb relative movements or dampen vibrations effectively.
Innovation Solution
A refrigerant line featuring a metal corrugated hose with a radially pressure-resistant, flexible plastic jacket made of aramid fibers, designed to support axial forces and dampen vibrations, combined with a braided plastic sleeve for enhanced strength and moisture resistance, and a press connection using the electromagnetic pulse method for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid pressure-resistant lines are used to withstand high CO2 pressure, then pressure resistance is improved, but flexibility and vibration damping capability deteriorate
Solution Approach 1:
The patent employs a corrugated metal hose with a flexible plastic jacket instead of rigid piping. The corrugated structure provides pressure resistance while maintaining flexibility, and the plastic jacket enhances both flexibility and vibration damping capabilities, allowing the system to adapt to relative movements between components.
Solution Approach 2:
The refrigerant line combines multiple materials with complementary properties: the corrugated metal hose provides structural strength and pressure resistance, while the plastic jacket adds flexibility and damping. This composite construction resolves the contradiction between rigidity for pressure resistance and flexibility for movement absorption.
2Adaptability or versatility
If traditional elastomer hoses are used for flexibility, then flexibility is improved, but pressure resistance under high CO2 pressure deteriorates
Solution Approach 1:
The corrugated metal hose with plastic jacket replaces traditional elastomer hoses. The corrugated structure provides the necessary pressure resistance for high CO2 applications while maintaining flexibility through its geometric design, eliminating the need for elastomer materials that cannot withstand the pressures.
3Strength
If metal mesh jacket is used for pressure resistance, then pressure resistance is improved, but vibration damping capability deteriorates
Solution Approach 1:
The patent changes the material parameter of the jacket from metal mesh to plastic, which fundamentally alters the damping characteristics. Plastic material provides superior vibration damping compared to metal mesh while maintaining adequate pressure resistance, thereby reducing the harmful vibrations and noise in the system.
4Force
If friction pairing between corrugated hose and metal mesh is used for support, then radial support is improved, but hose crest destruction under vibration deteriorates
Solution Approach 1:
The plastic jacket acts as an intermediary between the corrugated hose and the external environment, replacing direct metal-to-metal friction contact. This intermediary material reduces friction and prevents the destruction of hose crests under vibrational conditions while maintaining radial support 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
The solution creates a flexible, high-pressure-resistant line that effectively absorbs relative movements and dampens vibrations, maintaining structural integrity and preventing moisture ingress, with a minimum bursting pressure of 34 MPa and axial elongation of no more than 2% over operating conditions.
Implementation Method 1
the corrugated hose, which is known to be a flexible component, can now take over the gas-tight routing of the refrigerant. However, since it is not able to withstand the high pressures on its own, it has a radially pressure-resistant, flexible jacket
Implementation Method 2
this is radial Pressure-resistant, flexible jacket designed as a plastic and not metal mesh or fabric in such a way as to transmit the required radial support forces between the corrugated hose and metal jacket and at the same time assumes the task of a damping element for the vibrations that occur, in particular pulsations coming from the refrigerant compressor
Implementation Method 3
a press connection, preferably using the electromagnetic pulse method (EMP) on the with a metal connecting piece
Data Source
Figure 1
AI summary
The invention relates to a refrigerant line for air conditioning systems operated with carbon dioxide as a refrigerant, in particular air conditioning systems of motor vehicles, wherein the line is provided at at least one, preferably at both ends, with connection parts for connection to further components, in particular welded, characterized in that the line has an inner, refrigerant-tight corrugated hose (1) made of metal and connected to the connection parts (2, 3), and that the corrugated hose (1) is surrounded at a radial distance by a radially pressure-resistant axial support in the form of a flexible jacket (8) made of plastic, which is connected to the connection parts (2, 3).which preferably has a negative coefficient of thermal expansion at an operating temperature of 180°C relative to room temperature and preferably a strength- and flexibility-optimized geometry through the combination of low fiber weight between 100 and 600 dtex with a coverage of at least 98% woven in 48-64 bobbins with at least 4 and at most 24 threads.