Ventilation device for a ventilation, heating and/or air conditioning system of a motor vehicle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle heating, ventilation, and air-conditioning systems produce discomforting acoustic waves across a range of frequencies due to air circulation, with conventional Helmholtz modules only absorbing low-frequency waves effectively.
Innovation Solution
A ventilation device with a network of resonators having varying neck and cavity dimensions along the air flow direction, optimizing acoustic wave absorption across a predefined frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional Helmholtz module is used to absorb acoustic waves, then low-frequency acoustic wave absorption is improved, but absorption across a broader frequency range deteriorates
Solution Approach 1:
The acoustic attenuation member is segmented into multiple resonators arranged in series along the air flow direction. Each resonator has different cavity volumes and neck dimensions, creating distinct resonant frequencies. This segmentation allows the system to absorb acoustic waves across a broad frequency range by distributing absorption capabilities across multiple frequency-specific resonators, resolving the contradiction between specialized low-frequency absorption and broad frequency adaptability.
Solution Approach 2:
Each resonator in the network is designed with specific local qualities - different cavity volumes and neck dimensions tailored to target specific frequency ranges. The first resonator has larger cavity volume for lower frequencies, while subsequent resonators have progressively smaller volumes for higher frequencies. This local quality differentiation enables each resonator to optimize absorption at its designated frequency while collectively covering a broad spectrum.
2Ease of manufacture
If resonators with uniform dimensions are used, then manufacturing simplicity is improved, but acoustic wave absorption effectiveness across different frequencies deteriorates
Solution Approach 1:
The invention deliberately introduces local quality variations in resonator dimensions along the air flow direction. Each resonator's cavity volume and neck dimensions are specifically tailored to its position in the sequence, creating a gradient structure that targets different frequency ranges. This controlled non-uniformity optimizes acoustic absorption effectiveness across frequencies while maintaining systematic manufacturing through standardized production of individually configured resonators.
Solution Approach 2:
The invention systematically changes key parameters - cavity volume and neck dimensions - across the resonator network in a controlled manner. The cavity volumes follow a decreasing sequence from first to last resonator, and neck dimensions are adjusted accordingly. These parameter changes enable each resonator to resonate at different frequencies, effectively broadening the absorption spectrum while maintaining manufacturability through systematic design.
3Device complexity
If a single resonator type is used throughout the duct, then device complexity is reduced, but the ability to attenuate acoustic waves across a broad frequency range deteriorates
Solution Approach 1:
The resonator network is segmented into multiple distinct resonator types positioned in sequence along the air flow direction. Each segment (resonator) has unique cavity volume and neck dimensions optimized for specific frequency ranges. This segmentation strategy increases device complexity slightly but dramatically improves frequency range adaptability, as each segment contributes to absorbing a specific portion of the acoustic spectrum that uniform resonators would miss.
Solution Approach 2:
The invention implements systematic parameter changes across the resonator sequence - specifically, cavity volumes decrease from the first resonator to the last, with corresponding adjustments in neck dimensions. This parameter progression creates a frequency distribution that covers a broad spectrum. The controlled complexity introduced by these parameter variations is justified by the significant improvement in broad frequency range attenuation capability.
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 device effectively attenuates acoustic waves across a broader frequency range, enhancing passenger comfort by optimizing acoustic wave absorption.
Implementation Method 1
this type of acoustic attenuation member comprises a Helmholtz module that absorbs the acoustic waves at a predefined frequency
Implementation Method 2
The acoustic waves produced can cause discomfort to the driver and/or passengers. It is thus known to equip these heating, ventilation and/or air-conditioning systems with at least one acoustic attenuation member in order to absorb a maximum of acoustic waves
Data Source
AI summary
The main subject matter of the invention is a ventilation device including at least one duct intended to channel an air flow in an air flow direction inside the duct, the ventilation device including at least one acoustic attenuation member at least partially arranged around the duct and made up of a network of resonators, each resonator having at least one cavity and one neck connecting the cavity to the duct, the resonators that make up the network of resonators being distributed at least parallel to the air flow direction. A distance separating two necks varies along a direction parallel to the air flow direction and in that a volume of the cavities varies along the direction parallel to the air flow direction.