Transmission Lock-Up Clutch Precharge Under Lubricating Oil Pressure
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Solution Overview
Problem
In transmissions with hydraulic circuits connecting lubricating oil and lock-up clutch oil passages, controlling lubricating oil pressure affects lock-up clutch oil pressure, leading to inaccurate control of the lock-up clutch.
Innovation Solution
A transmission system with an oil pump, lock-up oil pressure control valve, lubricating oil pressure control valve, and a controller that adjusts precharge time based on lubricating oil pressure to prevent unintentional engagement of the lock-up clutch by setting precharge time shorter for higher lubricating oil pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lubricating oil pressure is controlled to reach the end of the lubrication portion, then the lubrication effectiveness is improved, but the lock-up clutch control accuracy deteriorates due to unintended engagement
Solution Approach 1:
The patent changes the precharge time parameter based on lubricating oil pressure levels. When lubricating oil pressure is high (first pressure), a shorter precharge time (first precharge time) is used. When lubricating oil pressure is low (second pressure), a longer precharge time (second precharge time) is used. This dynamic parameter adjustment prevents unintended lock-up clutch engagement while maintaining effective lubrication.
Solution Approach 2:
The patent implements dynamic control of the precharge time based on the actual lubricating oil pressure conditions. The controller adjusts the precharge time in real-time according to the lubricating oil pressure, making the system adaptive to varying operating conditions rather than using a fixed precharge time.
2Ease of operation
If a fixed precharge time is used for lock-up clutch engagement, then the control simplicity is maintained, but the accuracy of lock-up clutch engagement deteriorates under varying lubricating oil pressure conditions
Solution Approach 1:
The patent introduces variable precharge time parameters (first precharge time and second precharge time) that change based on lubricating oil pressure conditions, replacing the concept of a single fixed precharge time to achieve accurate engagement control.
Solution Approach 2:
The patent performs a preliminary precharge action before actual lock-up clutch engagement. This precharge phase fills the hydraulic circuit with oil at a controlled rate, and the duration of this preliminary action is adjusted based on lubricating oil pressure to ensure readiness for accurate engagement.
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
Enables accurate control of the lock-up clutch by considering the oil filling state of the hydraulic circuit, preventing unintentional engagement and ensuring precise precharge timing.
Implementation Method 1
an oil pump configured to discharge an oil to be supplied to the transmission mechanism
Implementation Method 2
a lock-up oil pressure control valve configured to adjust a pressure of the oil discharged from the oil pump and supply the oil to the lock-up clutch
Implementation Method 3
a lubricating oil pressure control valve configured to adjust the pressure of the oil discharged from the oil pump and supply the oil to a portion to be lubricated of the transmission mechanism
Data Source
AI summary
A transmission, includes a transmission mechanism including a torque converter having a lock-up clutch; an oil pump configured to discharge an oil to be supplied to the transmission mechanism; a lock-up oil pressure control valve configured to adjust a pressure of the oil discharged from the oil pump and supply the oil to the lock-up clutch; a lubricating oil pressure control valve configured to adjust the pressure of the oil discharged from the oil pump and supply the oil to a portion to be lubricated of the transmission mechanism; and a controller configured to control the lock-up oil pressure control valve. The controller controls the lock-up oil pressure control valve so that a precharge time when a lubricating oil pressure which is an oil pressure supplied from the lubricating oil pressure control valve is a first lubricating oil pressure becomes shorter than another precharge time when the lubricating oil pressure is a second lubricating oil pressure which is lower than the first lubricating oil pressure when performing a precharge of supplying the oil to the lock-up clutch.