Automatic Transmission Lock-Up Clutch Current Control
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Solution Overview
Problem
Conventional lock-up clutch control in automatic transmissions experiences pressure reduction issues due to oil consumption during gear change operations, leading to instability and impact on vehicle performance.
Innovation Solution
A method involving a controller that detects current signals to solenoid valves and adjusts current levels to the lock-up clutch based on oil temperature, target gear stage, and engine RPM, ensuring increased current application during initial fill and gear change completion to maintain stable pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control pressure of the lock-up clutch is maintained at a low level during gear change operation, then the gear change impact is reduced, but the pressure reduction causes impact to the vehicle due to oil consumption
Solution Approach 1:
The controller predicts the oil consumption of the lock-up clutch based on the operating state of the engaging element before the oil is actually consumed. When the engaging element is operated, the controller proactively adjusts the control pressure of the lock-up clutch in advance to compensate for the expected oil consumption, preventing pressure reduction and impact before they occur
Solution Approach 2:
The controller continuously monitors the operating state of the engaging element and uses this feedback to adjust the control pressure of the lock-up clutch. By detecting when the engaging element is operated, the controller dynamically modifies the lock-up clutch pressure to maintain stability despite oil consumption during gear change operations
2Loss of energy
If the operating area of the lock-up clutch is expanded to improve fuel efficiency, then the efficiency of the entire driving is improved, but a precise slip control is desired to maintain gear change feel
Solution Approach 1:
The control pressure of the lock-up clutch is dynamically adjusted based on the operating conditions and gear change state. The controller modifies the pressure in real-time according to the engaging element's operation, enabling precise slip control throughout the expanded operating area while maintaining gear change feel
Solution Approach 2:
The control pressure parameter of the lock-up clutch is changed based on the operating state of the engaging element. By adjusting this parameter dynamically during gear change operations, the system maintains precise slip control while operating in an expanded area for improved fuel 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 stabilizes gear change control by preventing pressure reduction in the lock-up clutch, enhancing overall vehicle performance by compensating for oil consumption during gear changes.
Implementation Method 1
a detecting step of detecting, by a controller, a current signal applied to a solenoid valve of an engaging element
Implementation Method 2
an amount of oil in a pump is consumed equal to the volume of the third clutch, during an initial fill time period when the third clutch is operated
Data Source
AI summary
The present disclosure relates to a method for controlling a lock-up clutch of an automatic transmission. The method includes: a detecting step of detecting, by a controller, a current signal applied to a solenoid valve of an engaging element when a gear change operation begins; and a first increasing control step of controlling, by the controller, an amount of current that is applied to a solenoid valve of a lock-up clutch during an initial fill time period when it is determined that the current signal is applied to the solenoid valve of the engaging element. In particular, the solenoid valve of the engaging element is used to form a gear stage, and the controller increases the amount of current to a predetermined level for a predetermined period of time.