Variable Frequency Helmholtz Resonator for Intake Noise
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Solution Overview
Problem
Current Helmholtz resonant cavities are ineffective for varying engine speeds as they are only optimized for specific frequencies, leading to the need for multiple cavities that increase costs and occupy excessive space in automobile intake systems.
Innovation Solution
A variable frequency Helmholtz resonant cavity system comprising two pipes with different cross-sectional areas and lengths, connected to the main intake system pipe via a control valve plate that adjusts the pipe's cross-sectional area and length to change the muffling frequency, allowing for manual, electromagnetic, or pressure-controlled operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple Helmholtz resonant cavities are used to cover varying engine speeds, then noise muffling effectiveness is improved, but installation space and cost increase
Solution Approach 1:
The patent applies the dynamics principle by making the Helmholtz resonant cavity adjustable through a control valve plate that can change the effective volume of the resonant cavity. This allows the same physical cavity to adapt its muffling characteristics dynamically to match different engine operating conditions, eliminating the need for multiple fixed-volume cavities and thereby reducing installation space while maintaining noise muffling effectiveness across varying engine speeds.
Solution Approach 2:
The patent applies parameter changes by modifying the volume parameter of the Helmholtz resonant cavity through the control valve plate mechanism. By changing the effective volume of the resonant cavity, the system can tune its muffling frequency to match different engine speeds, allowing a single cavity to replace multiple cavities with different fixed volumes, thus reducing installation space and cost.
2Reliability
If a large Helmholtz resonant cavity is used to reduce low-frequency noise, then noise muffling effectiveness is improved, but installation space increases
Solution Approach 1:
The patent uses the dynamics principle by implementing a controllable valve plate that can dynamically adjust the effective volume of the Helmholtz resonant cavity. This allows a smaller physical cavity to achieve the acoustic performance of a larger cavity by adjusting its effective volume through the valve mechanism, thereby reducing installation space while maintaining noise muffling effectiveness.
Solution Approach 2:
The patent applies parameter changes by modifying the volume parameter of the resonant cavity through the control valve plate. By changing the effective volume, the system can achieve the low-frequency noise muffling effect of a large cavity using a smaller physical structure, thus reducing installation space requirements.
3Volume of stationary object
If a single Helmholtz resonant cavity is used for specific frequency, then cost and installation space are reduced, but noise muffling effectiveness decreases
Solution Approach 1:
The patent applies dynamics by making the single resonant cavity adjustable through a control valve plate. This allows the cavity to adapt its characteristics to different operating conditions, enabling a single cavity to perform the function of multiple fixed-frequency cavities, thereby maintaining noise muffling effectiveness while reducing installation space and cost.
Solution Approach 2:
The patent applies universality by designing the Helmholtz resonant cavity with a control valve plate that enables it to serve multiple functions across different frequency ranges. The same physical cavity can be tuned to different muffling frequencies by adjusting the valve plate position, allowing one cavity to replace multiple specialized cavities and maintain comprehensive noise control 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
This solution reduces costs and space requirements while enhancing noise muffling effectiveness by allowing a single cavity to operate effectively across multiple frequencies, improving noise reduction in automobile intake systems.
Implementation Method 1
Helmholtz resonant cavity is an effective method to eliminate low frequency components of noises in automobile intake systems
Implementation Method 2
changing the cross-sectional area and length of the Helmholtz resonant cavity pipe, thereby adjusting the muffling frequency of the Helmholtz resonant cavity
Data Source
AI summary
A variable frequency Helmholtz resonant cavity includes a Helmholtz resonant cavity body, two Helmholtz resonant cavity pipes with different cross-sectional areas and lengths and a control valve plate. The Helmholtz resonant cavity body is connected with the main pipe of the intake system via the Helmholtz resonant cavity pipes, and the control valve plate is disposed at the location where the two Helmholtz resonant cavity pipes meet.