Helmholtz Resonator Intake Attenuation with Gravity Drainage
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Solution Overview
Problem
Existing acoustic attenuation devices for turbocharged engine intake lines, particularly those with annular resonance chambers and Helmholtz resonators, face issues of large size, limited resonance chambers, and inadequate noise attenuation across a wide frequency range, including unsatisfactory performance for low-frequency breath noises and high-frequency whistling noises.
Innovation Solution
The proposed acoustic attenuation device incorporates multiple Helmholtz resonators with axial transverse partitions and gravity-driven condensate evacuation orifices, which prevent condensate accumulation, enhance acoustic performance, and shift the attenuation frequency band to higher frequencies, while being compact and adaptable for integration into intake lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Helmholtz resonators are arranged radially outside an air circulation duct with transverse and longitudinal partitions, then acoustic attenuation is provided, but the device size becomes large and the number of resonance chambers is limited
Solution Approach 1:
The device is divided into multiple identical modular units, each comprising a Helmholtz resonator with specific partitions and openings. These modules can be arranged in series along the intake line, allowing scalable acoustic attenuation without proportionally increasing overall device complexity. Each module independently contributes to noise reduction across different frequency ranges.
Solution Approach 2:
The resonators are arranged axially along the intake line rather than radially around a single duct section. This axial arrangement in the longitudinal dimension allows multiple resonance chambers to be packed into a compact space, increasing the number of effective resonance chambers without radially expanding the device footprint.
2Device complexity
If condensates and oil are allowed to accumulate in the resonance chambers, then the structure remains simple, but the useful volume of the chamber decreases and acoustic attenuation is penalized
Solution Approach 1:
Condensate evacuation orifices are integrated into the resonance chamber structure at strategic locations. These orifices extract accumulated condensates and oil from the resonance chambers, preventing volume reduction while maintaining the overall simplicity of the device design. The extraction function is built into the existing chamber geometry without requiring separate complex drainage systems.
Solution Approach 2:
The condensate evacuation system operates automatically using gravity and pressure differentials. Condensates collected in the resonance chambers are self-evacuated through the orifices without requiring external power sources or complex mechanical pumping systems. The system serves itself by utilizing the natural flow dynamics of the intake air to drive condensate removal.
3Volume of moving object
If the resonance chamber volume is reduced to decrease device size, then compactness is achieved, but the acoustic attenuation performance deteriorates
Solution Approach 1:
Instead of using a single large resonance chamber, the device employs multiple smaller identical resonance chambers arranged in series. Each chamber provides a portion of the total acoustic attenuation required, and their combined effect achieves the desired noise reduction performance. This segmentation allows compact packaging while maintaining effective attenuation volume distributed across multiple units.
Solution Approach 2:
The acoustic performance is optimized by carefully adjusting geometric parameters of each resonance chamber including the volume of the resonating cavity, the area and position of openings in the partitions, and the dimensions of condensate evacuation orifices. These parameter optimizations ensure maximum acoustic attenuation from each unit, allowing smaller individual chamber volumes while maintaining overall system performance.
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 improves acoustic performance by maintaining resonance chamber volume, reducing pressure drops, and effectively attenuating noises across a broader frequency range, including low-frequency breath noises and high-frequency whistling noises, with reduced size and manufacturing costs.
Implementation Method 1
at least one resonance chamber forming a Helmholtz resonator which is arranged at the outside of this pipe structure and which communicates therewith by at least one opening formed in said wall
Implementation Method 2
said or each resonance chamber further comprises at least one orifice for the evacuation by gravity of condensates entrained by said fluid
Data Source
Figure 1~2
AI summary
The device (1) has a rectangular parallelepiped resonance chamber (8) forming a Helmholtz resonator in a case (6), where the resonator is communicated with a pipe structure (4) via oblong transverse openings (9, 10) for allowing passage of oil loaded pressurized gas fluid. The chamber is defined axially by transversal partitions (14, 15) in an axial direction (A) of the structure. The chamber has a circular evacuation orifice (16) that evacuates condensates driven by the fluid, by gravity and is formed in a cylindrical tubular wall (5) at the immediate proximity of one of the partitions.