Clutch Hydraulic Pressure Staging for Reliable Startup Stroke Control
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Solution Overview
Problem
The friction of clutch parts changes with operation states, leading to variations in clutch stroke start and end during system startup, making ineffective stroke elimination challenging in clutch devices.
Innovation Solution
A clutch control device with a control unit that sets target hydraulic pressures in stages: a higher first target pressure for startup, a lower second target pressure during stroke, and a third target pressure after stroke completion, with controlled switching and timing to manage friction and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single target hydraulic pressure is used during clutch operation, then the control system is simple, but the clutch stroke start and end vary due to friction changes, making ineffective stroke elimination unreliable
Solution Approach 1:
The patent divides the clutch operation process into three distinct phases with different target hydraulic pressures: initial phase (high pressure to overcome static friction and start stroke), intermediate phase (medium pressure to continue stroke), and final phase (low pressure to complete ineffective stroke elimination). This segmentation allows each phase to be optimized for its specific friction conditions, improving reliability without requiring complex real-time friction adaptation
Solution Approach 2:
The patent implements dynamic switching between different target hydraulic pressure values based on the clutch operation phase. The control unit transitions from a first target hydraulic pressure (higher) during initial stroke to a second target hydraulic pressure (lower) during intermediate stroke, and finally to a third target hydraulic pressure (lowest) after stroke completion. This dynamic adjustment adapts to the changing friction characteristics throughout the operation, ensuring reliable ineffective stroke elimination
2Productivity
If a higher hydraulic pressure is applied to quickly eliminate ineffective stroke, then the stroke elimination speed increases, but the power consumption increases
Solution Approach 1:
The patent applies periodic action by using high hydraulic pressure only during the initial phase when ineffective stroke elimination is most critical, then transitions to lower pressures for the remaining phases. This time-varying pressure application achieves quick stroke elimination when needed while minimizing power consumption during sustained operation, optimizing the balance between productivity and energy use
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 quick and reliable ineffective stroke elimination by managing friction and reducing power consumption, stabilizing clutch operation and maintaining a standby state effectively.
Implementation Method 1
a standby hydraulic pressure for performing ineffective stroke elimination at the time of the disconnection of a clutch to a hydraulically operated clutch device
Data Source
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AI summary
This clutch control device includes an engine (13), a transmission (21), a clutch device (26) configured to connect and disconnect motive power transmission between the engine (13) and the transmission (21), a clutch actuator (50) configured to drive the clutch device (26) and change a clutch capacity, and a control unit (60) configured to calculate a target value (Pt) of a control parameter (Ps) for the clutch capacity. When the target value (Pt) of the control parameter (Ps) immediately after system startup is defined as a first control target value (P1) and the target value (Pt) of the control parameter (Ps) during a clutch stroke at the time of the system startup is defined as a second control target value (P2), the control unit (60) is configured to set the first control target value (P1) to a value greater than the second control target value (P2).