Vehicle Ventilation Passage Shielding for Cabin Noise Reduction
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Solution Overview
Problem
Existing vehicle ventilation structures fail to provide sufficient sound insulation, allowing external noise to enter the passenger compartment through the inlet opening, despite the use of sound insulating materials in the ventilation passage.
Innovation Solution
A ventilation structure with a shielding plate integrated into the ventilation passage that intersects the noise entry path from the outlet opening to the inlet opening, combined with a seal member for enhanced noise suppression and a flap that closes the outlet opening when internal pressure is lower than external pressure to prevent noise entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sound insulating material is provided on part of the wall of the ventilation passage, then noise absorption is improved, but sufficient sound insulation effect for noise entering straight from the outlet opening toward the inlet opening cannot be obtained
Solution Approach 1:
The ventilation passage is divided into multiple sections with different treatments: sound insulating material is applied to the walls, and a shielding plate is positioned at the bottom to block direct noise propagation. This segmentation allows each component to address specific noise pathways independently, achieving comprehensive sound insulation where wall materials absorb diffuse noise and the shielding plate blocks direct noise travel from outlet to inlet.
Solution Approach 2:
Different portions of the ventilation passage are given different properties: the walls are covered with sound insulating material for noise absorption, while the bottom surface includes a shielding plate for direct noise blocking. This local differentiation of functional properties ensures that each area of the ventilation passage is optimized for its specific role in noise control, addressing both diffuse and direct noise pathways.
2Object-affected harmful factors
If a shielding plate is disposed in the ventilation passage to block noise, then noise shielding effect is improved, but the number of parts and mounting complexity increases
Solution Approach 1:
The shielding plate is integrated with the inlet opening structure, forming a unified component rather than a separate part. This merging eliminates the need for independent mounting of the shielding plate, reducing assembly steps and the number of discrete parts while maintaining the noise shielding function. The shielding plate becomes an integral part of the inlet opening assembly.
Solution Approach 2:
The inlet opening structure serves multiple functions: it provides the air intake opening, supports the shielding plate for noise blocking, and includes the sealing member for pressure equalization. By making the inlet opening structure multi-functional, the design reduces the total number of components needed in the ventilation system while achieving comprehensive noise shielding.
3Object-affected harmful factors
If a seal member is mounted on the shielding plate for close contact with the vehicle body panel, then noise shielding effect is enhanced, but noise generated due to contact between shielding plate and vehicle body panel increases
Solution Approach 1:
The seal member acts as an intermediary between the shielding plate and the vehicle body panel. It provides the necessary contact for structural support and enhanced noise shielding while simultaneously acting as a damping layer that absorbs contact vibrations and prevents direct rigid contact noise. The seal member mediates between the conflicting requirements of close contact for shielding and contact-free for noise reduction.
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
Effectively reduces external noise entry into the passenger compartment, improving quietness while simplifying mounting and reducing the number of parts, thus enhancing production efficiency and noise shielding without increasing the number of components.
Implementation Method 1
a shielding plate that extends to intersect a noise entry path from the outlet opening to the inlet opening is disposed in a middle of the ventilation passage
Implementation Method 2
a ventilation in which a part of a wall of the ventilation passage is formed of a sound insulating material, and the noise outside the vehicle is absorbed by the sound insulating material of the ventilation passage
Implementation Method 3
A seal member that is in close contact with the vehicle body panel inside the ventilation passage may be mounted on the shielding plate
Data Source
AI summary
A ventilation includes an inlet opening, an outlet opening, and a ventilation passage. The inlet opening is disposed in an interior space at a rear portion of a vehicle. The outlet opening exhausts air in the interior space that has passed through the inlet opening to the outside of the vehicle. The ventilation passage is formed by being surrounded by an interior member that faces the interior space and a vehicle body panel that covers the outside of the interior member, and allows communication between the inlet opening and the outlet opening. A shielding plate that extends to intersect a noise entry path from the outlet opening to the inlet opening is disposed in a middle of the ventilation passage.