Centrifugal Pendulum for Powertrain Torsional Vibration Damping
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Solution Overview
Problem
Existing drive train systems with internal combustion engines face challenges in efficiently managing torsional vibrations across different operating states, particularly with cylinder deactivation, requiring increased space for multiple centrifugal pendulums to cover various vibration frequencies.
Innovation Solution
A connecting device with a single centrifugal pendulum adapted to two natural frequencies of the internal combustion engine, allowing for optimal damping in both operating states with reduced installation space, integrated with a dual-mass flywheel or friction clutch, and featuring adjustable pendulum masses for effective damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple centrifugal pendulums are used to cover different vibration frequencies, then vibration damping performance is improved, but installation space increases
Solution Approach 1:
The single centrifugal pendulum is designed with multiple pendulum masses having different radii of gyration, allowing it to function as multiple pendulums simultaneously. This multi-functional design enables effective damping across different vibration frequencies (including fundamental and overtone frequencies) while occupying the space of only one pendulum component.
Solution Approach 2:
The centrifugal pendulum is segmented into multiple pendulum masses (first pendulum mass and second pendulum mass) with different radii of gyration. Each mass segment targets specific frequency ranges, with the first mass addressing fundamental frequencies and the second mass addressing overtone frequencies, collectively providing comprehensive vibration control.
2Area of stationary object
If a single centrifugal pendulum is used to reduce installation space, then space requirements are reduced, but adapting to multiple natural frequencies becomes difficult
Solution Approach 1:
The pendulum masses are designed with different radii of gyration (a key geometric parameter) to tune them to different natural frequencies of the engine. The first pendulum mass has a radius optimized for fundamental frequencies, while the second pendulum mass has a different radius for overtone frequencies, enabling a single pendulum structure to adapt to multiple frequency requirements.
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 provides efficient torsional vibration damping across all operating states while minimizing space requirements, ensuring optimal performance and adaptability to varying engine conditions.
Implementation Method 1
a torsional vibration damping device with at least one torsional vibration damper and at least one centrifugal pendulum to dampen the torsional vibrations of the drive train
Implementation Method 2
the centrifugal pendulum is tuned to the torsional vibration behavior of the first operating state and to the torsional vibration behavior of the second operating state
Implementation Method 3
the spring damper of the dual-mass flywheel as the first torsional vibration damper
Data Source
Figure 1~8
Figure 9~16
AI summary
The invention relates to a powertrain (10, 110, 210) comprising an internal combustion engine that has a given number of cylinders and features a first operating mode in which all cylinders are active as well as a second operating mode in which some of the cylinders are off, and comprising a torsional vibration damping device (12, 112, 212) that includes at least one torsional vibration damper (15, 19, 115, 119, 215, 219, 319) and at least one centrifugal pendulum (20, 120, 220, 320) which is adjusted to a torsional vibration behavior prevailing in the first operating mode and to the torsional vibration behavior prevailing in the second operating mode.