Electro-hydro-pneumatic Mount Assembly with Switchable Stiffness
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Solution Overview
Problem
Conventional mount assemblies in vehicles have a fixed spring stiffness profile that is not adaptable to changing operating conditions, limiting their effectiveness in reducing vibrations and forces transmission between structural members.
Innovation Solution
A mount assembly with a fluid-based system that includes multiple fluid chambers, a pressure compliant membrane, and a valve, allowing for the selection of different stiffness profiles by controlling the flow of fluid and air, enabling adjustable stiffness based on vehicle operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed spring stiffness profile is used in the compliant member, then the mount assembly structure is simple and easy to manufacture, but the stiffness cannot be adapted to changing vehicle operating conditions
Solution Approach 1:
The patent applies the dynamics principle by making the stiffness profile adjustable through a valve system that controls fluid flow between chambers. The compliant member's stiffness can be dynamically changed by opening or closing the valve, allowing adaptation to different vehicle operating conditions such as varying powertrain vibrations or different driving scenarios. This transforms a static structure into a dynamic, adaptive system.
Solution Approach 2:
The patent employs pneumatic and hydraulic principles by using fluid-filled chambers (first and second fluid chambers) connected through a fluid conduit and controlled by a valve. The fluid pressure and flow within these chambers directly influence the stiffness characteristics of the compliant member. By regulating the fluid distribution, the system achieves variable stiffness without mechanical reconfiguration.
2Reliability
If a fixed stiffness profile is used, then the manufacturing cost is lower, but the vibration reduction performance is limited under varying operating conditions
Solution Approach 1:
The dynamics principle enables the mount assembly to adapt its stiffness profile dynamically through a valve-controlled fluid system. This allows the same physical structure to provide different vibration reduction characteristics based on real-time operating conditions, significantly improving reliability across diverse scenarios without requiring multiple specialized components.
Solution Approach 2:
The patent applies parameter changes by modifying the fluid pressure and distribution parameters within the chambers to alter the stiffness profile. The valve controls the flow of fluid between chambers, changing the pressure parameters that directly affect the compliant member's mechanical properties. This allows continuous adjustment of stiffness without changing the physical structure.
3Adaptability or versatility
If multiple stiffness profiles are implemented, then the adaptability to different operating conditions is improved, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing a single compliant member structure that can perform multiple stiffness functions through the fluid control system. Rather than requiring separate compliant members for different stiffness levels, one multi-functional component achieves variable stiffness by redirecting fluid flow, reducing the number of parts needed.
Solution Approach 2:
The valve acts as an intermediary element that mediates between the fluid chambers and the compliant member. By controlling fluid flow through this intermediary component, the system achieves stiffness adjustment without direct mechanical intervention in the compliant member structure, simplifying the overall control mechanism.
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 system achieves adjustable stiffness profiles, allowing for optimal vibration reduction and force transmission management according to varying vehicle conditions, enhancing the performance of the mount assembly beyond fixed stiffness limitations.
Implementation Method 1
The first and second fluid chambers are filled with a hydraulic fluid, such as glycol
Implementation Method 2
The third fluid chamber is filled with air
Implementation Method 3
The pressure compliant membrane is attached to the second support structure and seals the opening between the second fluid chamber and the third fluid chamber
Data Source
AI summary
A system and method using a mount assembly for attaching a powertrain to a structural member of a vehicle. The mount assembly includes a first compliant member, a second compliant member, a first fluid chamber, a second fluid chamber, a third fluid chamber, a pressure compliant membrane, and a valve. A fluid conduit interconnects the first fluid chamber with the second fluid chamber to allow a fluid to pass from the first fluid chamber to the second fluid chamber. The third fluid chamber has an opening in communication with the second fluid chamber and a vent port. The pressure compliant membrane seals the opening between the second fluid chamber and the third fluid chamber. The valve selectively seals the vent port in the third fluid chamber. A first stiffness profile of the mount assembly is selected by actuating the valve to open the vent port. A second stiffness profile of the mount assembly is selected by actuating the valve to close the vent port.