Chassis Cross-Member Damper Layout for Vehicle NVH Reduction
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Solution Overview
Problem
Vehicles experience NVH issues due to the compounding of natural resonant frequencies from various vibration modes, leading to interior noise and vibration problems.
Innovation Solution
Incorporation of a damper within the vehicle chassis, specifically positioned within a U-shaped cross-member beneath the floor panel, to alter the natural frequency of vibration modes and mitigate NVH issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a damper is added to the vehicle chassis to reduce NVH issues, then noise and vibration are reduced, but device complexity increases
Solution Approach 1:
The damper assembly is nested within the U-shaped cross-member structure of the chassis. The cross-member's hollow U-shaped configuration allows the damper to be positioned inside it, integrating the noise reduction function into the existing structural framework without adding external components.
Solution Approach 2:
The U-shaped cross-member serves dual functions: it provides structural support to the floor panel and simultaneously houses the damper assembly. This multi-functionality reduces the need for separate structural and NVH control components, thereby limiting the increase in device complexity.
2Object-affected harmful factors
If the damper mass is increased to improve NVH performance, then vibration reduction is enhanced, but weight of the vehicle increases
Solution Approach 1:
The damper utilizes a relatively small mass (1.5-2.0 kg) that is strategically positioned and tuned to target specific frequency ranges (160-200 Hz). This approach achieves effective vibration reduction in critical frequency bands without requiring large mass, thereby limiting weight increase.
Solution Approach 2:
The damper mass is concentrated in a compact form factor and positioned at a specific location within the cross-member where it can most effectively counteract floor panel vibrations. This localized approach maximizes vibration reduction efficiency per unit of mass added.
3Object-affected harmful factors
If the damper is positioned within the U-shaped cross-member, then NVH performance is improved, but manufacturing complexity increases due to welding requirements
Solution Approach 1:
The damper is designed to fit within the U-shaped cross-member, and locating members are used to guide proper positioning during assembly. This nesting approach with built-in alignment features simplifies the manufacturing and installation process compared to designing a completely new integrated structure.
Solution Approach 2:
Locating members serve as intermediary components that facilitate the connection between the damper and the cross-member. These members simplify the welding process by providing predefined attachment points and alignment, reducing manufacturing complexity.
4Object-affected harmful factors
If the damper structure is made more complex to achieve better frequency tuning, then NVH performance is improved, but device complexity increases
Solution Approach 1:
The damper achieves effective NVH control by tuning the natural frequency of the floor panel through a relatively simple mass addition. The frequency tuning is achieved by adjusting the mass value (1.5-2.0 kg) and its position, rather than through complex structural modifications, thereby maintaining simplicity.
Solution Approach 2:
The damper operates by introducing a mass that creates a counter-vibrating effect at the target frequency range (160-200 Hz). This passive vibration control mechanism achieves system response reduction through dynamic balancing rather than through complex structural damping elements.
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 damper effectively reduces noise and vibration in the frequency range of 160 Hz to 200 Hz by shifting the natural frequency, thereby improving the vehicle's NVH performance.
Implementation Method 1
NVH issues (e.g., interior noise within the passenger seating area, vibration in the steering wheel, etc.) that result from the compounding of the natural resonant frequencies of several vibration modes
Implementation Method 2
The damper is configured to shift the natural frequency of the floor panel, reduce noise and vibration
Data Source
AI summary
A vehicle that includes a chassis, which defines a passenger seating area, and a damper that is connected to the chassis beneath a floor panel of the vehicle such that the damper is positioned rearwardly of the passenger seating area.