Switchable Absorber Duct Hydromount for Variable Engine Stiffness
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Solution Overview
Problem
Existing hydromounts face challenges in dynamically adjusting stiffness to effectively dampen vibrations during both idle and driving operations of a motor vehicle engine, as they struggle to balance low stiffness for idle operation and high stiffness for driving operation.
Innovation Solution
Incorporation of a switchable absorber duct connecting the working and compensating chambers, with a switchable actuating member that can be electrically, pneumatically, or mechanically controlled to open or close the absorber duct, thereby adjusting the dynamic stiffness based on the operational state of the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the hydromount uses a fixed stiffness structure, then it can provide high stiffness for driving operation, but it cannot achieve low stiffness for idle operation
Solution Approach 1:
The hydromount employs a switchable absorber duct that can dynamically change its flow resistance state between open and closed positions. This allows the mount to transition between different stiffness characteristics: low stiffness when the duct is open (for idle operation) and high stiffness when the duct is closed (for driving operation), thereby resolving the contradiction between adaptability and fixed structure
Solution Approach 2:
The invention changes the flow resistance parameter of the absorber duct through the switching device. By adjusting the flow resistance between low (open state) and high (closed state), the system achieves variable stiffness characteristics without fundamentally changing the mechanical structure, thus improving adaptability while controlling complexity
2Ease of operation
If the absorber duct is always open, then the dynamic stiffness is reduced for improved idle operation isolation, but the damping capability during driving operation is insufficient
Solution Approach 1:
The switching device enables the absorber duct to dynamically adjust its state based on operational requirements. During idle operation, the duct remains open to reduce stiffness and improve vibration isolation. During driving operation, the duct closes to increase stiffness and enhance damping capability, thus resolving the contradiction between ease of operation and reliability
Solution Approach 2:
The system employs periodic switching of the absorber duct state corresponding to the operational cycles of the engine (idle vs. driving). The switching device responds to operational conditions by periodically changing the duct state, allowing the mount to optimize performance for each operational phase
3Reliability
If the absorber duct is always closed, then the stiffness is high for effective driving operation damping, but the isolation of high-frequency vibrations during idle operation is reduced
Solution Approach 1:
The switchable absorber duct provides dynamic adjustment capability, allowing the system to transition between closed state (high stiffness) for driving operation and open state (low stiffness) for idle operation. This resolves the contradiction between reliability and ease of operation by adapting the stiffness characteristic to the current operational mode
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 solution allows for reduced dynamic stiffness during idle operation for improved isolation of high-frequency vibrations and increased stiffness during driving operation for effective damping of low-frequency, high-amplitude vibrations, enhancing the overall vibration damping capabilities of the hydromount.
Implementation Method 1
The working chamber is made larger or smaller by a movement of the supporting spring, whereby a hydraulic pressure is built up in the working chamber. Due to the pressure, the liquid located in the working chamber is pressed via the damping ducts into the compensating chamber.
Implementation Method 2
The vibrations caused by road bumps are dampened by a hydraulic system, with the hydraulic system being formed by the liquid-dampened working chamber, the compensating chamber, and the damping ducts.
Implementation Method 3
In order to decouple high-frequency, low-amplitude vibrations, i.e. in the acoustically relevant range, the incorporation of an elastic diaphragm within the nozzle systems is known. In this case, the membrane vibrates with high-frequency, low-amplitude vibrations, so that a damping action is decoupled via the damping duct.
Data Source
AI summary
A hydromount that is suitable for mounting a motor vehicle engine at a vehicle body includes a supporting spring supporting a mount core and surrounding a working chamber, and a compensating chamber separated from the working chamber by a separating assembly and delimited by a compensating diaphragm. The separating assembly may have at least two nozzle systems which have one decoupling diaphragm each and in each of which one damping duct is disposed. The compensating chamber and the working chamber may be filled with a liquid and may be connected to each other in a liquid-conducting manner by damping ducts. The separating assembly may have an absorber duct connecting the working chamber with the compensating chamber. A switchable actuating member may be assigned to the absorber duct.