Torsional Vibration Damping System with Centrifugal Pendulums
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Solution Overview
Problem
Existing drive trains with internal combustion engines face challenges in achieving improved torsional-vibration behavior across different operating states, particularly when switching between full and reduced cylinder operations, as existing torsional-vibration damping systems are not adequately adaptable to varying vibration orders and torque levels.
Innovation Solution
A drive train design incorporating multiple torsional-vibration dampers and centrifugal pendulums, where each component is specifically adapted to the torsional-vibration behavior of either operating state, with adjustable damper stages and spring devices to optimize damping and torque transmission based on the operational mode, utilizing divided flywheels and friction clutch discs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single torsional-vibration damper is used in the drive train, then the device complexity is reduced, but the adaptability to different operating states (vibration orders and torque levels) deteriorates
Solution Approach 1:
The drive train is divided into multiple damping zones with separate torsional-vibration dampers positioned at different locations (e.g., on the crankshaft and on the transmission input shaft). Each damper is optimized for specific operating conditions, allowing the system to handle different vibration orders and torque levels effectively without requiring a single complex adaptive damper.
Solution Approach 2:
The torsional-vibration dampers are designed with universal applicability across multiple operating states. By using multiple dampers with different characteristics rather than one complex adaptive damper, the system achieves multi-functionality where each damper handles specific operating conditions, collectively providing adaptability to all states.
2Reliability
If multiple damper stages with different stiffness are provided, then the torsional-vibration damping for different torque levels is improved, but the device complexity increases
Solution Approach 1:
The damping system is segmented into multiple damper stages with different stiffness characteristics. Each stage is optimized for specific torque levels and vibration conditions. The segmented approach allows the system to provide appropriate damping for low-torque, high-torque, and transient conditions without requiring a single complex variable-stiffness damper.
Solution Approach 2:
The damper stages are designed with dynamic characteristics that allow them to engage selectively based on operating conditions. The different stiffness values enable the dampers to adapt dynamically to varying torque levels and vibration frequencies, providing optimal damping performance across the entire operating range.
3Reliability
If centrifugal pendulums are adapted to specific vibration orders, then the torsional-vibration behavior for specific operating states is improved, but the adaptability to other operating states deteriorates
Solution Approach 1:
The centrifugal pendulum system is segmented into multiple pendulums with different adaptation characteristics. Each pendulum is optimized for specific vibration orders corresponding to different operating states (e.g., all cylinders operating vs. some cylinders switched off). This segmentation allows the system to effectively damp vibrations across multiple operating states without requiring a single complex adaptive pendulum.
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 enhances torsional-vibration damping and torque handling in both operating states by selectively engaging damper stages with appropriate stiffness and pendulum adaptations, ensuring effective vibration isolation and torque management across varying engine loads.
Implementation Method 1
at least one centrifugal pendulum, wherein a centrifugal pendulum and optionally a torsional-vibration damper are adapted to the torsional-vibration behavior of one operating state
Implementation Method 2
a spring device that is arranged between a primary inertial mass associated with the crankshaft, and a secondary inertial mass associated with a transmission input shaft
Implementation Method 3
a torsional-vibration damper with at least one damper stage in a clutch disc of a friction clutch
Data Source
AI summary
A drive train is disclosed that includes an engine operable in a first engine operating state and a second engine operating state and a torsional-vibration damping system operatively connected to the engine. The torsional-vibration damping system includes a first torsional-vibration damper having a primary inertial mass and a secondary inertial mass, a second torsional-vibration damper, a first centrifugal pendulum arranged on the secondary inertial mass of the first torsional-vibration damper, and a second centrifugal pendulum arranged on the second torsional-vibration damper.