Fluid-Filled Engine Mounting Absorbing Longitudinal Vibration
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Solution Overview
Problem
Conventional fluid-filled engine mounting devices are inadequate in absorbing longitudinal vibrations generated during engine operation, leading to reduced ride performance and durability issues, especially during rapid acceleration and deceleration.
Innovation Solution
The proposed fluid-filled engine mounting apparatus incorporates a longitudinal vibration absorbing device with a decoupler and multiple fluid chambers to effectively manage and absorb both small and large displacement vibrations, utilizing a working fluid that flows through gaps and reduction chambers to control vibration amplitude across various frequency domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional insulator is used to mount the engine, then the structure is simple, but it is insufficient to adequately absorb various vibrations of the engine generated in a wide frequency band
Solution Approach 1:
The patent introduces a fluid-filled mounting device where a working fluid (hydraulic fluid) is contained within the insulator and flows through gaps formed between the insulator and housing during vibration. The fluid's compressibility and viscosity provide superior damping characteristics across wide frequency bands, replacing conventional solid insulators and enabling effective absorption of both vertical and longitudinal vibrations.
Solution Approach 2:
The mounting device combines multiple materials with different properties: the insulator (rubber or elastomer), housing (metal), and working fluid (hydraulic fluid). This composite structure leverages the elasticity of the insulator, the strength of the housing, and the damping characteristics of the fluid to achieve comprehensive vibration absorption that neither material could accomplish alone.
2Reliability
If the dynamic characteristics are reduced by lowering a loss factor in conventional fluid-filled mounting, then the vibration absorption improves, but the ride performance deteriorates during vehicle driving
Solution Approach 1:
The patent creates a dynamic system where the gap between the insulator and housing changes during operation. During vertical vibration, the gap opens allowing fluid flow for damping. During longitudinal vibration and normal driving, the gap closes providing rigid support. This dynamic behavior allows the system to adapt its characteristics based on the type of vibration or load applied, maintaining both vibration absorption and ride performance.
3Reliability
If conventional fluid-filled engine mounting apparatus is used, then vertical vibrations are efficiently absorbed, but longitudinal vibration generated during engine startup, shutdown, and rapid acceleration/deceleration cannot be absorbed
Solution Approach 1:
The patent designs the insulator-housing gap structure to handle multiple types of vibration simultaneously. The same fluid-filled mechanism that absorbs vertical vibration also absorbs longitudinal vibration when the gap opens in the longitudinal direction. This universal design eliminates the need for separate mounting devices for different vibration directions, providing comprehensive NVH control.
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 significantly improves noise, vibration, and harshness (NVH) performance by efficiently absorbing both vertical and longitudinal vibrations, enhancing vehicle rigidity and ride comfort, while reducing nonlinear frequency amplitudes and road noise, thus improving durability and stability during vehicle operations.
Implementation Method 1
a working fluid flows upward and downward in the fluid chamber through the gap
Implementation Method 2
utilizing a working fluid that flows through gaps and reduction chambers to control vibration amplitude across various frequency domains
Data Source
AI summary
A fluid-filled engine mounting apparatus may include a core provided with a center into which a center bolt is inserted; an insulator with an internal lower portion in which a first fluid chamber is formed and with an upper internal circumferential surface adhered to an external circumferential surface of the core; an upper housing mounted on an upper portion of the insulator; upper and lower orifice plates mounted on an internal circumferential surface of the insulator and are provided with a center hole; a membrane mounted on the center holes between the upper and lower orifice plates; a first case mounted on a lower external circumferential surface of the insulator; a first diaphragm mounted on a lower portion of the insulator that closes the first fluid chamber; and a longitudinal vibration absorbing device provided at an upper portion of the insulator.