Torque Converter Clutch Control for NVH and Efficiency
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Solution Overview
Problem
Torque converter clutch engagement in vehicles often results in inefficient energy transfer due to unrestrained slippage and noise, vibration, and harshness (NVH) issues, limiting the realization of potential efficiency gains to specific vehicle operating conditions.
Innovation Solution
A method for controlling the actuation of a torque converter clutch by monitoring transmission input speed and adjusting engine speed to maintain a desired minimum engine speed, thereby controlling the clutch actuation based on the comparison between the engine speed and the desired minimum speed, ensuring efficient torque transmission and reduced NVH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the torque converter clutch is fully engaged to improve torque transmission efficiency, then energy transfer is improved, but noise, vibration and harshness (NVH) increase due to engine torque perturbations passing directly through the clutch
Solution Approach 1:
The patent applies dynamics by transitioning the clutch from a static fully engaged state to a dynamic slipping mode. The clutch is controlled to maintain a predetermined slip rate between the impeller and turbine, allowing the system to adaptively balance torque transmission efficiency with NVH reduction. This dynamic operation enables the clutch to continuously adjust its engagement level based on operating conditions.
Solution Approach 2:
The patent changes the operational parameters of the clutch by introducing controlled slippage. Instead of maintaining full engagement (zero slip), the system operates the clutch in a slipping mode with a predetermined slip rate. This parameter change allows the clutch to absorb engine torque perturbations while still providing improved torque transmission efficiency compared to traditional fully engaged operation.
2Object-affected harmful factors
If the torque converter clutch operates in slipping mode to reduce NVH, then noise, vibration and harshness are minimized, but torque transmission efficiency is reduced due to unrestrained slippage
Solution Approach 1:
The patent applies partial action by implementing a predetermined slip rate rather than allowing unrestrained slippage. The clutch is engaged to the extent necessary to provide improved torque transmission efficiency while maintaining controlled slippage to reduce NVH. This partial engagement approach optimizes the balance between efficiency and comfort.
Solution Approach 2:
The patent employs feedback control to maintain the predetermined slip rate. The system continuously monitors the difference between impeller and turbine speeds and adjusts clutch actuation to maintain the target slip rate. This feedback mechanism ensures that the clutch operates in the optimal slipping mode, balancing torque transmission efficiency with NVH reduction.
3Productivity
If the torque converter clutch is fully engaged to improve fuel economy, then energy efficiency is improved, but the range of vehicle operating conditions is limited due to NVH restrictions
Solution Approach 1:
The patent applies universality by enabling the clutch to perform multiple functions across different operating conditions. The clutch can operate in fully engaged mode for maximum efficiency, in slipping mode for NVH reduction, and can transition between these states. This multi-functionality allows the system to optimize fuel economy across a broader range of vehicle operating conditions rather than being restricted to specific scenarios.
Solution Approach 2:
The patent uses dynamic control to adapt the clutch engagement level to varying operating conditions. The system can transition between fully engaged and slipping modes based on real-time conditions, enabling fuel economy optimization across diverse scenarios including different speeds, loads, and driving patterns, rather than being limited to fixed operating ranges.
4Adaptability or versatility
If the torque converter clutch is fully released to allow unrestrained slippage, then adaptability to different operating conditions is improved, but torque transmission efficiency is reduced due to energy loss in the fluid
Solution Approach 1:
The patent applies partial action by implementing controlled slippage rather than unrestrained slippage. The clutch is partially engaged to maintain a predetermined slip rate, providing improved adaptability compared to full engagement while reducing energy loss compared to full release. This partial engagement optimizes the balance between adaptability and efficiency.
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 approach enhances torque converter efficiency, improves fuel economy, and minimizes NVH by maintaining optimal engine speed and clutch engagement, allowing for improved energy transfer across a broader range of vehicle operations.
Implementation Method 1
torque is transmitted therebetween based upon the flow of hydraulic fluid between the impeller and the turbine
Implementation Method 2
A torque converter clutch can include a pressurized fluid-actuated friction device engageable to mechanically couple the impeller
Implementation Method 3
a torque converter clutch can include a pressurized fluid-actuated friction device engageable to mechanically couple the impeller
Implementation Method 4
Other torsionals, typically those above about 20 Hz, are absorbed in a torsional damper device, which is an element of the torque converter
Data Source
AI summary
A method for controlling actuation of a torque converter clutch includes monitoring a transmission input speed, comparing the monitored transmission input speed to a threshold input speed, and, when the transmission input speed is less than the threshold input speed, controlling an engine speed based upon a desired minimum engine speed. Controlling the engine speed based upon the desired minimum engine speed includes monitoring a minimum engine speed critical parameter, determining the desired minimum engine speed based upon the minimum engine speed critical parameter, comparing the engine speed to the desired minimum engine speed, and controlling actuation of the clutch device based upon a result of the comparing the engine speed to the desired minimum engine speed.