Adjustable Helmholtz Resonator for Engine Intake Noise
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Solution Overview
Problem
Existing Helmholtz resonators for internal combustion engines lack the ability to adjust noise attenuation levels, particularly in supercharged engines where high-pitched noise can be objectionable, and do not allow for variable tuning to address different frequency ranges effectively.
Innovation Solution
An adjustable Helmholtz resonator assembly with a movable second cylindrical sleeve member that can block or unblock orifices to switch between active and inactive states, allowing for selective noise attenuation, featuring a housing with multiple volumes and orifices that cooperate to form Helmholtz resonators, and an actuator controlled by a controller to adjust the sleeve member's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed Helmholtz resonator is used, then noise attenuation at a specific frequency is achieved, but the ability to adjust noise attenuation levels and tune different frequency ranges is lost
Solution Approach 1:
The patent applies the dynamics principle by making the resonator adjustable through a movable second sleeve member that can shift between different positions. This movement dynamically changes the effective volume of the resonator chamber and the position of orifices, enabling the resonator to be tuned to different frequencies and attenuation levels rather than being fixed at a single configuration.
Solution Approach 2:
The patent segments the resonator into multiple functional components: a first sleeve member with orifices, a second sleeve member with additional orifices that can move relative to the first, and a chamber. This segmentation allows independent optimization of each component and enables the second sleeve to selectively block or unblock orifices, providing discrete adjustment steps for noise attenuation.
2Adaptability or versatility
If the second sleeve member blocks all orifices, then the resonator is deactivated and noise attenuation is prevented, but the system cannot selectively attenuate noise at different frequencies
Solution Approach 1:
The patent applies partial action by allowing the second sleeve member to block only certain orifices while leaving others open. This selective blocking enables partial activation of the resonator, where specific frequency ranges can be attenuated while others remain unaffected, providing granular control over noise reduction rather than all-or-nothing operation.
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
Enables flexible noise reduction in internal combustion engines by allowing the attenuation of noise-producing pressure pulsations to be switched on or off and tuned across various frequencies, accommodating user preferences regarding noise levels, especially in supercharged engines.
Implementation Method 1
A Helmholtz resonator includes a resonance volume or chamber having a small opening, typically referred to as a neck. The neck is operable to enable communication between the resonance chamber and the intake air pipe. Sound waves generated by components within the internal combustion engine travel along the intake air pipe where their acoustic pressure impinges on the neck and excites a mass of air within the neck. The acoustic pressure within the resonance chamber reacts against the air mass within the neck and produces an out-of-phase acoustic pressure at the intake air pipe to cause cancellation of intake noise at the resonant frequency.
Data Source
AI summary
An adjustable Helmholtz resonator assembly is provided having an active state and an inactive state. In the active state the Helmholtz resonator assembly is operable to attenuate pressure pulsations within air passing therethrough. In the inactive state the Helmholtz resonator assembly does not attenuate pressure pulsations within air passing therethrough. The Helmholtz resonator assembly is preferably configured to be mounted within an intake system of an internal combustion engine.