Torque Converter Lock-Up Clutch Calibration via Multi-Clutch Speed Control
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Solution Overview
Problem
Existing control methods for calibrating the actuation of a converter lock-up clutch in hydrodynamic torque converters do not effectively manage rotation speed differences between the pump and turbine wheels, leading to inefficiencies and potential damage due to uneven clutch torque distribution.
Innovation Solution
A control method that involves opening and closing multiple clutches associated with power-split shaft assemblies to apply clutch torque to the turbine wheel, adjusting the number and activation of clutches across defined ranges to achieve a specified rotation speed difference, thereby managing the clutch torque distribution and maintaining the set-point rotation speed difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single shifting element is used to brake the turbine wheel for calibration, then the device complexity is reduced, but the manufacturing precision and control accuracy of rotation speed difference deteriorates
Solution Approach 1:
The patent divides the calibration function into multiple segments by using at least two clutches (first clutch and second clutch) associated with different power-split shaft assemblies. Each clutch can be independently actuated to apply clutch torque to the turbine wheel, enabling segmented control of the rotation speed difference between pump wheel and turbine wheel. This segmentation allows for more precise and flexible calibration compared to using a single clutch.
2Manufacturing precision
If multiple clutches are used to apply clutch torque to the turbine wheel, then the manufacturing precision of rotation speed difference control is improved, but the device complexity increases
Solution Approach 1:
The patent makes the multiple clutches serve universal calibration functions. Both the first clutch and second clutch are capable of applying clutch torque to the turbine wheel for calibration purposes, and they can be used in combination or individually depending on the calibration requirements. This multi-functionality allows the clutches to handle various calibration scenarios without requiring additional dedicated components, thus improving precision while limiting the increase in complexity.
3Reliability
If clutch torque is applied to the turbine wheel during calibration, then the reliability of converter lock-up clutch actuation is improved, but the object-generated harmful factors (clutch wear) increase
Solution Approach 1:
The patent segments the clutch torque application across multiple clutches (first clutch and second clutch) during calibration. By distributing the torque application across different clutches associated with different power-split shaft assemblies, the wear on each individual clutch is reduced compared to concentrating all calibration torque on a single clutch. This segmentation enables reliable calibration while mitigating excessive wear on any one clutch component.
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 allows for precise control of rotation speed differences, reduces clutch wear by distributing torque across multiple clutches, and enables reliable calibration of the converter lock-up clutch, enhancing the longevity and performance of the transmission system.
Implementation Method 1
at least two clutches respectively associated with a power-split shaft assembly, which clutches can be actuated separately to open and close in order to apply a clutch torque to the turbine wheel
Data Source
AI summary
A method for calibrating an actuation of a converter lock-up clutch of a hydrodynamic torque converter having a pump wheel and a turbine wheel connected to a power-split transmission. The transmission has at least two clutches each connected to a respective power-split shaft assembly and each configured be actuated separately to close and open in order to apply a clutch torque to the turbine wheel so that a rotation speed difference between the pump wheel and the turbine wheel changes. The method includes opening the converter lock-up clutch and the at least two clutches each connected to a respective power-split shaft assembly of the transmission, rotating the pump wheel with a specified rotation speed, and applying a clutch torque to the turbine wheel as a function of an actual rotation speed difference. Clutches connected to a different respective power-split shaft assembly of the transmission are actuated in the closing direction.