Filtering Pulley Coupling Control for Torsional Vibration Isolation
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Solution Overview
Problem
Existing filtering pulleys for internal combustion engines are complex, costly, and inefficient in coupling and decoupling, leading to noise, shocks, and reduced fatigue life, particularly in hybrid systems where the crankshaft needs to be decoupled from the transmission.
Innovation Solution
A filtering pulley system with a hub and crown design featuring elastic groups and an actuator mechanism, controlled by an electronic unit, allows for selective coupling and decoupling through a splined coupling system actuated by magnetic attraction, optimizing torque transmission based on operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a filtering pulley with elastic elements is used to filter torsional oscillations, then vibration filtering is improved, but the system becomes complex and costly
Solution Approach 1:
The pulley is divided into two independent rotatable components: a first pulley element connected to the drive shaft and a second pulley element connected to the transmission belt. These segments can rotate independently relative to each other, allowing vibration filtering without requiring a complex fixed structure. The segmentation enables each element to handle specific functions while reducing overall structural complexity.
Solution Approach 2:
The invention introduces a dynamic coupling mechanism where the first and second pulley elements can selectively couple and decouple based on operational conditions. A sensor detects torsional oscillations and controls an actuator that engages or disengages the coupling between pulley elements. This dynamic adjustment allows the system to adapt to varying vibration conditions, filtering when needed and operating in rigid mode when not, thereby reducing complexity compared to always-filtering designs.
2Loss of energy
If the pulley is decoupled from the crankshaft in hybrid systems, then energy efficiency is improved, but coupling and decoupling operations generate noise and shocks
Solution Approach 1:
The coupling between pulley elements is made dynamic rather than static. The actuator selectively engages or disengages the coupling between the first and second pulley elements based on real-time operational conditions detected by sensors. This allows smooth transitions between coupled and decoupled states, reducing mechanical shocks and noise compared to abrupt engagement/disengagement in traditional systems.
Solution Approach 2:
The second pulley element acts as an intermediary between the drive shaft and the transmission belt. When decoupled from the first pulley element, it can continue to rotate freely, mediating the disconnection smoothly. This intermediary component absorbs the transition forces during coupling and decoupling operations, reducing the transmission of shocks and noise to the transmission system while maintaining energy efficiency in hybrid mode.
3Adaptability or versatility
If traditional coupling and decoupling methods are used, then the pulley can be disconnected, but the fatigue life is reduced leading to sudden breakages
Solution Approach 1:
The system transitions from static coupling to dynamic coupling where the connection between pulley elements can be adjusted in real-time. The actuator-controlled engagement and disengagement allows for controlled, gradual coupling rather than abrupt mechanical connection. This dynamic approach reduces stress concentration and fatigue loading on the pulley components, extending their service life while maintaining the ability to couple and decouple as needed for different operating modes.
Solution Approach 2:
A sensor system continuously monitors the operational conditions including torsional oscillations, torque, and speed. This feedback is used by the control unit to determine the optimal timing for coupling and decoupling the pulley elements. By using feedback-based control, the system avoids coupling during high-stress conditions and ensures smooth engagement when conditions are favorable, thereby reducing fatigue damage and preventing sudden breakages while maintaining operational versatility.
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 system efficiently decouples and couples the pulley components without friction or interference, enhancing system efficiency, reducing noise and extending the pulley's lifespan while adapting to hybrid and electric modes.
Implementation Method 1
an actuator mechanism, controlled by an electronic unit, allows for selective coupling and decoupling through a splined coupling system actuated by magnetic attraction
Implementation Method 2
one or more elastic elements through which the driving torque is transmitted from the hub to the crown
Data Source
AI summary
A filtering pulley has a hub configured to be fixed to a shaft for rotation thereabout, a crown mounted coaxial and rotationally free on the hub, and a plurality of elastic groups arranged circumferentially with respect to the hub and to the crown and interposed, each, between a pair of first elements integral with the hub and between a pair of second elements integral with the crown. The first elements have at least two spokes, carried by an actuator that is made of two portions that can be selectively coupled based on angular position data between the crown and the hub and/or based on data of torque transmitted between the different elements of the system comprising this pulley.