Noise control article
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Solution Overview
Problem
Conventional noise control products for vehicles, such as those used in front of dash applications, face limitations including poor noise reduction across frequency ranges, degradation after heat exposure, inadequate conformability, and high weight, which hinder effective noise and vibration reduction in vehicles with noisy engines and exhaust systems.
Innovation Solution
A conformable noise control article comprising a nonwoven fiber web impregnated with a polymeric matrix, including low and high glass transition temperature polymers, additives, and inorganic fillers, which increases density and air flow resistivity, allowing for effective noise reduction across low, mid, and high frequencies, and maintains performance under heat exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional noise control products (felt fabrics with reinstated fabric) are used, then they provide basic noise reduction, but they exhibit poor reduction of low frequency, mid-frequency and high frequency noise
Solution Approach 1:
The patent uses a composite material consisting of a nonwoven fiber web impregnated with a polymeric matrix. The fiber web provides structural framework while the polymer matrix fills the voids to create a dense composite structure. This composite approach enables effective noise reduction across low, mid, and high frequency ranges by combining the advantages of both materials - the mechanical structure of fibers and the damping properties of the polymer matrix.
Solution Approach 2:
The patent changes the physical parameters of the noise control material by impregnating the fiber web with polymeric matrix, which increases the density from the original fiber density to a final density at least ten times more than the nonwoven fiber web density. This parameter change transforms the material from a lightweight fabric to a dense, effective noise control composite that blocks sound transmission across all frequency ranges.
2Object-generated harmful factors
If conventional noise control products are used, then they provide initial noise reduction, but they exhibit poorer noise reduction properties after extended exposure to heat
Solution Approach 1:
The patent selects polymers with specific glass transition temperatures to maintain structural integrity at elevated temperatures. The low Tg polymer provides flexibility and noise damping at operating temperatures, while the high Tg polymer ensures thermal stability and prevents degradation during extended heat exposure. This dual-polymer approach changes the thermal parameters of the material to resist thermal degradation.
Solution Approach 2:
The composite structure of fiber web impregnated with polymer matrix provides thermal stability. The fiber framework maintains structural integrity while the polymer matrix with appropriate Tg selection resists thermal degradation, creating a composite material that maintains noise reduction properties after extended heat exposure.
3Ease of operation
If conventional noise control products are used, then they can be installed, but they exhibit inadequate conformability leading to gaps between the NVH product and the vehicle frame
Solution Approach 1:
The patent creates a flexible noise control article by impregnating a nonwoven fiber web with polymeric matrix. The resulting composite maintains flexibility and conformability similar to conventional fabrics, allowing it to be molded into complex shapes and conform to vehicle frame contours without creating gaps that would allow noise leakage.
Solution Approach 2:
The patent changes the density parameter of the material to be at least ten times more than the nonwoven fiber web density, while maintaining conformability. The polymeric matrix impregnation increases density for noise blocking while the flexible fiber-polymer composite structure allows the material to conform to complex geometries and fill gaps effectively.
4Object-generated harmful factors
If conventional noise control products are used, then they provide noise reduction, but they exhibit high weight adding undesirable weight to the vehicle
Solution Approach 1:
The patent optimizes the density parameter by impregnating a lightweight nonwoven fiber web with polymeric matrix to achieve a final density at least ten times more than the original fiber web. This parameter change creates a material that is dense enough for effective noise reduction but starts from a lightweight fiber substrate, reducing overall weight compared to conventional dense noise control materials.
Solution Approach 2:
The composite structure combines a lightweight nonwoven fiber web with a polymeric matrix to create a material that achieves high noise reduction effectiveness with reduced weight. The fiber web provides structural framework with minimal weight, while the polymer matrix provides the density needed for noise blocking, creating an optimized weight-to-performance ratio.
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 noise control article provides flexible, lightweight noise reduction, maintaining sound transmission loss performance across a wide frequency spectrum and resisting thermal degradation, making it suitable for high-temperature applications like the front of dash or firewall areas in vehicles.
Implementation Method 1
a nonwoven fiber web impregnated with a polymeric matrix... air flow resistivity of the noise article is greater than the air flow resistivity of the nonwoven fiber web, and the noise article produces a sound transmission loss (STL) in the frequency spectrum of 125 Hz to 5000 Hz
Implementation Method 2
The matrix comprises a low glass transition temperature (Tg) polymer, high glass transition temperature (Tg) polymer... maintains performance under heat exposure
Data Source
AI summary
A conformable noise control article useful reducing noise in a motor vehicle is provided. The article includes a nonwoven fiber web that is impregnated with a polymeric matrix composition having low (Tg) and high (Tg) polymers, additives and inorganic fillers. The density of the noise control article is at least ten times more than the density of the nonwoven fiber web. The article has an air flow resistivity that is at least ninety times greater than the air flow resistivity of a bare nonwoven web and exhibits a sound transmission loss in the frequency spectrum of 125 Hz to 5000 Hz.