Dual-Pipe Coolant Piping with Air Gap for Noise Reduction
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Solution Overview
Problem
Air conditioning systems experience noise issues due to pulsations in coolant flow, which cause vibrations in piping, leading to discomfort for passengers, especially in automotive systems, and existing noise-reducing solutions are costly, heavy, and difficult to recycle.
Innovation Solution
A dual-pipe design with an inner and outer pipe separated by an air gap, where the outer pipe surrounds the inner pipe over at least 55% of its length, creating a distinct vibrational system with different resonance frequencies to suppress vibrations and noise, and using the same material for both pipes to reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If damping materials (rubber foam, TPE, or other plastic materials) are applied on the outside wall of the pipe to suppress vibrations, then noise is reduced, but manufacturing costs increase, weight increases, dimensions increase, and recycling becomes problematic
Solution Approach 1:
The piping system is segmented into an inner pipe and an outer pipe with different resonance frequencies, eliminating the need for additional damping materials. This segmentation approach reduces manufacturing complexity and costs while maintaining noise reduction effectiveness.
Solution Approach 2:
The outer pipe serves multiple functions: it acts as a structural component, provides thermal insulation through the air gap, and reduces noise by having different resonance frequencies than the inner pipe. This multi-functionality eliminates the need for separate damping materials, reducing both cost and weight.
2Object-affected harmful factors
If damping materials are applied on the outside wall of the pipe to suppress vibrations, then noise is reduced, but weight increases
Solution Approach 1:
The outer pipe provides structural support, thermal insulation, and noise reduction in a single component, eliminating the need for additional heavy damping materials. The air gap between pipes provides thermal insulation without adding significant weight.
3Object-affected harmful factors
If damping materials are applied on the outside wall of the pipe to suppress vibrations, then noise is reduced, but dimensions increase
Solution Approach 1:
The outer pipe is nested around the inner pipe with a minimal air gap, creating a compact structure that reduces noise without significantly increasing the overall diameter. This nested configuration is more space-efficient than applying thick damping materials on the outer surface.
4Object-affected harmful factors
If damping materials are applied on the outside wall of the pipe to suppress vibrations, then noise is reduced, but recycling becomes problematic
Solution Approach 1:
Both the inner and outer pipes are made from the same material (aluminum), creating a homogeneous structure that is easily recyclable. This eliminates the recycling complications associated with combining different materials like metal pipes and plastic damping materials.
5Object-affected harmful factors
If the outer pipe surrounds the inner pipe over a longer distance, then noise reduction is improved, but device complexity increases
Solution Approach 1:
The outer pipe surrounds the inner pipe over at least 55% of the inner pipe's length, which is sufficient to achieve effective noise reduction without requiring the outer pipe to cover the entire length. This partial coverage reduces structural complexity while maintaining effectiveness.
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 dual-pipe design effectively reduces noise emissions while maintaining a smaller diameter and eliminating the need for additional insulation or connecting means, providing thermal insulation and efficient condensate drainage, thus enhancing passenger comfort and reducing production costs.
Implementation Method 1
the air gap between the two pipes acts as an insulation layer for the inner pipe carrying the coolant
Implementation Method 2
the two pipes have different resonance frequencies. The two pipes together form a vibrational system with a resonance frequency that differs significantly from the one of a single pipe
Data Source
AI summary
A piping (10) for a coolant circuit comprising an inner pipe (12) and an outer pipe (14) is shown. The inner pipe (12) carries the coolant and the outer pipe (14) surrounds the inner pipe (12) at least partly in a way that an air gap (18) between the inner pipe's outer radius and the outer pipe's inner radius is present.