Crankshaft Damper and Dual-Mass Flywheel for Low-Speed Isolation
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Solution Overview
Problem
Existing crankshaft arrangements struggle to achieve optimal isolation of drive trains while balancing torsional vibrations and mechanical stability, particularly in low-speed operations, and existing vibration damping methods are costly or complex.
Innovation Solution
A crankshaft arrangement incorporating a dual-mass flywheel with a torsional vibration damper and an additional coupling featuring negative stiffness, which integrates an inertia ring to the secondary side of the coupling, enhancing the isolation of drive trains by combining a dual-mass flywheel with a torsional vibration damper and negative stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stiffness of the elastomer coupling is reduced to lower isolation frequency, then drive train isolation is improved, but the elastomer coupling cannot transmit static torque and the static torsion angle becomes too large exceeding permissible limits
Solution Approach 1:
The system is divided into two separate components: a torsional vibration damper with primary mass and inertia ring for handling dynamic vibrations, and an elastomer coupling for transmitting static torque. This segmentation allows each component to be optimized independently - the damper can use softer elements for better isolation while the coupling maintains sufficient stiffness for torque transmission.
Solution Approach 2:
The torsional vibration damper acts as an intermediary element between the crankshaft and the elastomer coupling. It absorbs and dampens torsional vibrations before they reach the coupling, allowing the coupling to operate within its optimal stiffness range while still achieving good drive train isolation.
2Reliability
If a tuned mass damper or rotational speed-adaptive damper is used to reduce rotational non-uniformities, then vibration damping is improved, but system costs increase due to additional seismic mass
Solution Approach 1:
The torsional vibration damper and elastomer coupling are merged into a single integrated system where the damper components (primary mass, inertia ring, viscous fluid) are combined with the coupling elements. This integration achieves effective vibration damping without requiring separate expensive damping systems.
Solution Approach 2:
The torsional vibration damper is designed to automatically adapt to varying operating conditions through its passive viscous fluid damping mechanism and inertial elements, eliminating the need for complex active control systems or rotational speed-adaptive mechanisms while maintaining effective vibration reduction across different engine speeds.
3Adaptability or versatility
If a flywheel-integrated damper and coupling (FIDC) is used to dampen torsional vibrations and isolate the drive train, then both functions are combined in one system, but the isolation of the drive train does not provide significant advantages over conventional design
Solution Approach 1:
The system uses locally optimized components with specific properties tailored to their functions: the viscous fluid provides targeted torsional damping where needed, while the elastomer coupling provides localized flexibility for drive train isolation. This local quality optimization achieves better overall performance than uniform design approaches.
Solution Approach 2:
The system employs composite construction combining different materials and mechanisms: viscous fluid damping elements, elastomeric coupling materials, and inertial masses are combined to create a multi-functional system that achieves both effective torsional vibration damping and superior drive train isolation simultaneously.
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 configuration significantly reduces torsional vibrations and rotational non-uniformity, improving drive train isolation and reducing mechanical stress, especially at low speeds, while maintaining system stability and efficiency.
Implementation Method 1
the primary mass and the inertia ring are coupled via a viscous fluid
Implementation Method 2
the primary mass is coupled to a secondary coupling via an elastic coupling device
Implementation Method 3
this additional coupling comprises a negative stiffness, which results in the desired behavior
Data Source
AI summary
A crankshaft arrangement for a combustion engine includes a crankshaft and a torsional vibration damper having a primary mass and an inertia ring. The primary mass is fixedly connected to the crankshaft, and the inertia ring and the primary mass are coupled via a viscous fluid. The torsional vibration damper is attached to an output end of the crankshaft. The primary mass is coupled to a secondary coupling via an elastic coupling device. The torsional vibration damper is coupled to the secondary coupling via a feedback device. The secondary coupling is formed as a dual-mass flywheel with a primary flywheel, a secondary flywheel and the elastic coupling device. A method for damping torsional vibrations of a crankshaft of a crankshaft arrangement is provided.