Clutch Hydraulic Air Bleeding Control With Pressure-Based Completion Check
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Solution Overview
Problem
In clutch-by-wire systems, air bleeding operations are difficult due to the presence of an actuator between the clutch lever and the clutch device, leading to potential actuator overload and inability to determine air bleeding completion by hand feel.
Innovation Solution
A clutch control device with an air bleeding mode that increases hydraulic pressure to a predetermined value, maintains it, and then decreases it, while switching to a completion check mode to determine air bleeding completion based on pressure changes within a specified time, minimizing actuator overload and allowing for air bleeding operation regardless of clutch lever operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the actuator is interposed between the clutch lever and the clutch device in a clutch-by-wire system, then the clutch operation can be controlled electrically, but air bleeding operation becomes difficult and the actuator may be overloaded
Solution Approach 1:
The control unit executes a preliminary air bleeding routine that automatically increases hydraulic pressure to a predetermined value, maintains it for a specified duration, and then decreases it. This preliminary action prepares the hydraulic circuit for air removal without requiring manual operation of the clutch lever, thus resolving the contradiction between electrical automation and ease of air bleeding operation
Solution Approach 2:
The system performs air bleeding automatically through the control unit's internal routines, eliminating the need for external manual intervention. The actuator serves itself by executing pressure cycles based on control unit instructions, making the air bleeding process as automatic as the clutch operation control
2Reliability
If hydraulic pressure is increased to bleed air in a clutch-by-wire system, then air can be removed from the hydraulic circuit, but the actuator may be overloaded
Solution Approach 1:
The control unit dynamically adjusts the hydraulic pressure profile during air bleeding by increasing pressure to a predetermined value, maintaining it for a specified time, and then decreasing it. This dynamic pressure management ensures air is effectively removed while preventing excessive load on the actuator, resolving the contradiction between air removal reliability and actuator strength
Solution Approach 2:
The control unit implements a cushioning mechanism by limiting the maximum hydraulic pressure to a predetermined value and controlling the pressure increase rate. This beforehand cushioning prevents the actuator from being overloaded during the air bleeding process while still achieving effective air removal from the hydraulic circuit
3Ease of operation
If manual operation of the clutch lever is used to determine air bleeding completion, then the operator can feel the pressurization degree, but this method is not applicable in clutch-by-wire systems
Solution Approach 1:
The control unit uses feedback from hydraulic pressure sensors to automatically determine air bleeding completion. The system monitors whether the hydraulic pressure increases from a first predetermined value to a second predetermined value within a specified time period, replacing the need for manual tactile feedback and making the determination process compatible with automated clutch-by-wire operation
4Productivity
If the actuator operates without proper air bleeding control, then the system can function, but hydraulic pressure may not reach desired levels
Solution Approach 1:
The control unit executes a preliminary air bleeding routine that automatically increases hydraulic pressure to a predetermined value, maintains it for a specified duration, and then decreases it. This preliminary action prepares the hydraulic circuit for air removal without requiring manual operation of the clutch lever, thus resolving the contradiction between electrical automation and ease of air bleeding operation
Solution Approach 2:
The system performs air bleeding automatically through the control unit's internal routines, eliminating the need for external manual intervention. The actuator serves itself by executing pressure cycles based on control unit instructions, making the air bleeding process as automatic as the clutch operation control
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
Facilitates air bleeding operations in clutch-by-wire systems by minimizing actuator overload and enabling determination of air bleeding completion without relying on hand feel, ensuring efficient hydraulic pressure management.
Implementation Method 1
a hydraulic circuit provided between the clutch device and the clutch actuator
Implementation Method 2
an air bleeding device configured to perform air bleeding of the hydraulic circuit; the air bleeding switch configured to enable hydraulic pressure of the hydraulic circuit to increase in the air bleeding mode
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, a hydraulic circuit (63) provided between the clutch device (26) and the clutch actuator (50), an air bleeding device (64) configured to perform air bleeding of the hydraulic circuit (63), a control unit (60) configured to calculate a control target value of the clutch capacity, a control mode changeover switch (59) configured to enable a control mode of the control unit (60) to be switched to an air bleeding mode, and an air bleeding switch (65) configured to enable a hydraulic pressure of the hydraulic circuit (63) to increase in the air bleeding mode.