Air distribution pipe for an HVAC circuit of a vehicle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
HVAC air distribution pipes in vehicles fail to effectively attenuate noise from the fan and compressor, particularly at low frequencies, leading to discomfort for passengers.
Innovation Solution
A single-layer tubular air distribution pipe made from a cellular, elastically deformable material with microperforations on its internal and/or external surfaces, extending radially across the pipe's thickness, which enhances acoustic attenuation across a broader frequency range, including low frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional single-layer tubular pipe made from cellular material is used, then the pipe structure remains simple and manufacturing is easy, but acoustic attenuation is insufficient particularly at low frequencies
Solution Approach 1:
The patent applies porous materials by creating microperforations in the pipe wall, transforming the solid cellular material into a porous structure. These microperforations allow acoustic energy to enter the pipe wall where it is absorbed and dissipated, significantly improving noise attenuation particularly at low frequencies while maintaining the simplicity of the single-layer pipe structure
Solution Approach 2:
The patent changes physical parameters of the pipe wall by introducing microperforations with specific dimensions (diameter 0.1-10mm, spacing 1-100mm). This parameter modification transforms the acoustic properties of the pipe, enabling it to attenuate low frequency sounds that would otherwise pass through the conventional solid cellular material
2Object-affected harmful factors
If the pipe wall is made solid without microperforations, then air leakage is prevented, but acoustic energy cannot be absorbed effectively
Solution Approach 1:
The patent applies local quality by creating microperforations that are locally distributed across the pipe wall surface. These localized openings are sufficient for acoustic absorption but too small and numerous to create meaningful air leakage, thus maintaining air tightness while enabling sound energy entry for absorption
Solution Approach 2:
The patent converts what would normally be considered a defect (the need for air tightness) into a benefit by using the microperforated structure. The same feature that could potentially allow air leakage is designed with such small dimensions and appropriate spacing that it actually improves air sealing while simultaneously enabling acoustic energy absorption
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 microperforated design significantly improves noise absorption and attenuation, particularly at frequencies between 50 and 800 Hz, providing a more comfortable driving experience by reducing engine and equipment noise transmission.
Implementation Method 1
the microperforations being made from the inside and/or the outside of the pipe and being through or not through... the pipe according to the invention can, on the contrary, have a more extensive acoustic attenuation property, including at low frequencies
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Air distribution pipe (34) for an HVAC circuit of a vehicle, this pipe (34) comprising a single single-layer tubular wall (36) made from a cellular and elastically deformable material, said wall (36) comprising acoustic attenuation micro-perforations, these micro-perforations extending from at least one of the internal and external surfaces of the wall (36) towards the other of these surfaces, or even to the other of these surfaces.