Pulley Pressure Damping Circuit for Stable Lock-Up Clutch Control
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Solution Overview
Problem
The existing hydraulic circuits for pulley pressure control valves experience oscillations in line pressure, leading to fluctuations in pulley pressures and poor controllability of the lock-up clutch due to inadequate damping performance, especially when the low pilot pressure is set too low.
Innovation Solution
A damping pressure supply circuit is introduced, comprising a pressure regulator valve, first pilot valve, second pilot valve, and third pilot valve, where the second pilot pressure is used as the source for the lock-up solenoid valve and the third pilot pressure is set as a damping pressure for the pulley pressure control valves, allowing for appropriate controllability and damping performance by being lower than the line pressure limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the low pilot pressure is set equal to or higher than the lower limit of the line pressure set range, then the lock-up clutch controllability is improved, but the damping performance of the pulley pressure control valve deteriorates due to oscillations in the damping pressure
Solution Approach 1:
The invention segments the pressure control system into multiple independent pilot valves (first, second, and third pilot valves) that generate different pilot pressures (first, second, and third pilot pressures) from the same line pressure source. This segmentation allows each valve to operate with optimized pressure levels for its specific function, resolving the contradiction between lock-up clutch controllability and damping pressure stability.
Solution Approach 2:
The invention applies local quality by providing different pressure characteristics to different parts of the system: the second pilot pressure is maintained at a level suitable for lock-up clutch control, while the third pilot pressure is specifically optimized for damping performance in the pulley pressure control valve. This localized optimization resolves the contradiction by allowing each subsystem to have its pressure parameters independently tuned.
2Stability of the object's composition
If the low pilot pressure is set too low to improve damping performance, then the damping performance of the pulley pressure control valve is improved, but the lock-up clutch controllability deteriorates due to narrower signal pressure range
Solution Approach 1:
The invention segments the pressure supply system so that the second pilot valve supplies pressure optimized for lock-up clutch control, while the third pilot valve supplies pressure optimized for damping performance. This segmentation eliminates the trade-off by providing independent pressure sources for each function.
Solution Approach 2:
The invention introduces an intermediary third pilot valve that derives its pressure from the second pilot pressure but provides a specifically optimized damping pressure to the pulley pressure control valve. This intermediary component mediates between the lock-up clutch control requirements and damping performance requirements.
3Adaptability or versatility
If two pilot valves are used to generate two types of pilot pressures, then the system complexity is increased, but the ability to independently control lock-up clutch and pulley pressure damping is improved
Solution Approach 1:
The invention segments the pressure control function across three pilot valves, where each valve handles a specific pressure generation task. This segmentation improves adaptability by allowing independent optimization of each pressure source while maintaining manageable system complexity through clear functional separation.
Solution Approach 2:
The invention achieves multi-functionality by having the second pilot pressure serve dual purposes: as the source pressure for the lock-up solenoid valve and as the source for generating the third pilot pressure for damping control. This universal use of the second pilot pressure optimizes system efficiency while providing independent control capability.
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 configuration ensures the controllability of the lock-up clutch and damping performance of the pulley pressure control valves by setting the third pilot pressure lower than the line pressure limit while maintaining appropriate second pilot pressure levels, preventing oscillations and engagement shocks.
Implementation Method 1
a pressure regulator valve that regulates a pressure of oil discharged from an oil pump to a line pressure
Implementation Method 2
a first pilot valve that generates a first pilot pressure with the line pressure as a source pressure
Implementation Method 3
a second pilot valve that generates a second pilot pressure with the first pilot pressure as a source pressure
Implementation Method 4
a third pilot valve that generates a third pilot pressure with the second pilot pressure as a source pressure
Implementation Method 5
The third pilot pressure is introduced as a damping pressure into a primary pulley pressure control valve that controls the primary pulley pressure
Data Source
AI summary
A hydraulic control circuit includes a pressure regulator valve, a first pilot valve, a second pilot valve, and a third pilot valve. A first pilot pressure is introduced as a source pressure into the primary solenoid valve that generates a primary signal pressure and a secondary solenoid valve that generates a secondary signal pressure. A second pilot pressure is introduced as a source pressure into a lock-up solenoid valve that generates the lock-up signal pressure. A third pilot pressure is introduced as a damping pressure into a primary regulator valve that controls a primary pulley pressure according to the primary signal pressure, and into a secondary regulator valve that controls a secondary pulley pressure according to the secondary signal pressure.