Active Damper for Driveline Torsional Vibration Mitigation
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Solution Overview
Problem
Existing driveline vibration dampers, particularly those using rubber-based tuned absorbers, are ineffective in mitigating prop shaft torsional vibrations and noise across varying engine speeds and driving scenarios, as they are tuned to specific frequencies and fail to adapt to changing resonant frequencies during acceleration and deceleration.
Innovation Solution
An active damping system that utilizes a prop shaft with a sealed damper housing containing active damping fluid, whose viscosity is dynamically adjusted by a viscosity changing unit controlled by a controller, allowing real-time adaptation to mitigate torsional vibrations and noise across all frequencies and scenarios. This system includes a hydraulic actuator and clutch assembly to alter friction forces and rotational speeds, using magnetorheological or electrorheological fluids to change viscosity in response to engine and vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubber-based tuned absorber dampers are used, then vibration is reduced at specific engine speeds, but the dampers are ineffective at other speeds and frequencies
Solution Approach 1:
The patent employs a variable viscosity damping fluid that can dynamically adjust its damping characteristics in real-time based on operating conditions. The fluid's viscosity changes from a first viscosity at a first operating point to a second viscosity at a second operating point, enabling the damper to adapt to different engine speeds and torsional vibration frequencies throughout the vehicle's operating range.
Solution Approach 2:
The patent changes the physical parameter of the damping fluid (viscosity) to optimize performance across different operating conditions. By controlling the viscosity of the damping fluid through temperature variation or other means, the system maintains effective vibration reduction across a broad frequency spectrum rather than being limited to a single tuned frequency.
2Device complexity
If a single-frequency tuned damper is used, then the device complexity is low, but the adaptability to different driving scenarios is limited
Solution Approach 1:
The patent modifies the physical parameters of the existing damper structure by introducing a variable viscosity damping fluid. This approach maintains the basic damper geometry and mounting structure while adding a control mechanism that adjusts fluid viscosity based on operating conditions, thereby achieving multi-scenario adaptability without substantially increasing structural complexity.
3Ease of operation
If the damping fluid viscosity is kept constant, then the system is simple to control, but it cannot mitigate vibrations across all frequencies and driving scenarios
Solution Approach 1:
The patent implements a self-regulating damping system where the damping fluid automatically adjusts its viscosity in response to changing operating conditions. The system uses the engine's own operational parameters (temperature, speed) to trigger viscosity changes, eliminating the need for external sensors or complex electronic control systems while maintaining adaptability across all driving scenarios.
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 active damping system effectively reduces driveline vibrations and noise across multiple frequencies and driving scenarios, enhancing user experience by providing consistent noise reduction and vibration mitigation, unlike static systems which are limited to specific frequencies.
Implementation Method 1
The active damping fluid is a magnetorheological fluid... the viscosity changing unit is an electromagnet configured to receive a control signal from the controller and change the viscosity of the active damping fluid in response to the control signal with an electromagnetic field
Implementation Method 2
the active damping fluid is an electrorheological (ER) fluid... the viscosity changing unit is a current generator configured to receive a control signal from the controller, and configured to change the viscosity of the active damping fluid in response to the control signal
Implementation Method 3
an active damping fluid contained within the damper housing. A viscosity of the active damping fluid is changeable based on a torsional vibration of the prop shaft
Data Source
AI summary
An active damping system for a driveline includes a prop shaft configured to transmit engine power from an engine to a load, a sealed damper housing, and an active damping fluid contained within the sealed damper housing. A viscosity of the active damping fluid is changeable based on a torsional vibration of the prop shaft. The active damping system further includes a piston fixed to a side of the prop shaft and in communication with the active damping fluid. The piston is configured to rotate about an axis of the prop shaft. The system further includes a viscosity changing unit in communication with the active damping fluid, and a controller operatively connected to the viscosity changing unit. The controller is configured to cause the viscosity changing unit to change a viscosity of the active damping fluid. The viscosity of the active damping fluid changes the torsional vibration.