Lockup Clutch Control via Dynamic Torque Model
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Solution Overview
Problem
Existing torque converter systems face challenges in controlling the engagement of the lockup clutch, particularly in managing torque transmission during the engagement process, which affects the efficiency and performance of the engine-transmission interface.
Innovation Solution
A method and system for controlling the engagement of the lockup clutch in a torque converter by retrieving a dynamic model that defines torque transmission based on operating parameters, monitoring these parameters, and modifying the lockup clutch command to ensure synchronized rotational speeds between the pump and turbine, using a control circuit and actuator to adjust the clutch engagement pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the lockup clutch engagement is controlled using conventional methods, then the structural complexity is reduced, but the torque transmission control precision deteriorates
Solution Approach 1:
The patent implements a feedback control system where the actual torque transmitted by the lockup clutch is continuously monitored and compared with the desired torque. The controller adjusts the lockup clutch engagement based on the torque feedback signal, enabling precise torque transmission control. This closed-loop feedback mechanism resolves the contradiction by achieving high precision control through intelligent algorithms rather than complex mechanical structures.
Solution Approach 2:
The patent replaces conventional mechanical torque control mechanisms with an electronically controlled system. The lockup clutch engagement is controlled through electronic signals that regulate hydraulic pressure, substituting mechanical linkages with electronic actuators and control algorithms. This substitution achieves precise torque control while maintaining relatively simple device architecture.
2Power
If the lockup clutch engagement pressure is increased to improve torque transmission, then the torque transmission capability is improved, but the risk of clutch slippage and overheating increases
Solution Approach 1:
The patent employs dynamic control of the lockup clutch engagement pressure rather than static fixed pressure. The controller continuously adjusts the engagement pressure based on real-time operating conditions including torque demand, rotational speed differential, and clutch temperature. This dynamic adjustment enables the system to transmit high torque when needed while preventing excessive pressure that could cause slippage or overheating, thus resolving the contradiction between power capability and harmful effects.
Solution Approach 2:
The patent changes multiple operating parameters simultaneously to optimize torque transmission while preventing harmful effects. The controller adjusts engagement pressure, engagement timing, and pump rotational speed based on feedback signals. By coordinating changes in these parameters, the system achieves high torque transmission capability while maintaining safe operating conditions that prevent clutch slippage and overheating.
3Stability of the object's composition
If the pump rotational speed is reduced to synchronize with turbine speed, then the engagement smoothness is improved, but the torque converter response time deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-positioning the pump rotational speed closer to the turbine speed before initiating lockup clutch engagement. The controller reduces the pump speed in advance to minimize the speed differential that would otherwise cause shock and vibration during engagement. This preliminary speed synchronization improves engagement smoothness while the overall response time remains acceptable because the speed adjustment begins before the engagement command is executed.
Data Source
AI summary
A dynamic model is stored in memory that defines torque transmitted by the lockup clutch as a function of a plurality of torque converter operating parameters. A lockup clutch command is asserted to control engagement the lockup clutch, and thereafter a number of the plurality of torque converter operating parameters are monitored. A profile is selected of one of the plurality of torque converter operating parameters, and the profile is configured to result in an intersection of rotational speeds of the pump and the turbine over time when inserted into the model along with the monitored values of the number of torque converter operating parameters. The model is continually solved over time using the selected profile and the monitored operating parameters to produce transmitted torque values, and the lockup clutch command is modified based on the transmitted torque values.