Double Clutch Actuating Force Limiting via Pressure Sensors
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Solution Overview
Problem
Double clutches actuated by hydrostatic systems face reliability issues due to high total actuating forces during normal and fault conditions, which can exceed the maximum force of individual clutches, potentially damaging components and requiring stronger, more costly materials.
Innovation Solution
The method employs pressure sensors to limit the total actuating force by detecting faults and allowing operation with a single clutch, disengaging affected gears, and calculating and limiting the actuating forces to prevent excessive stress, enabling a limp-home function and protecting components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two individual clutches are actuated simultaneously during overlapping shifting operation, then the shifting function is improved, but the total actuating force exceeds the maximum force of an individual clutch, causing component stress and potential damage
Solution Approach 1:
The control system performs preliminary detection of fault conditions using pressure sensors before catastrophic failure occurs. When a fault is detected in one clutch, the system proactively limits the actuating force of the other clutch to prevent excessive total force, thereby protecting components while maintaining limited operational capability.
Solution Approach 2:
The system dynamically changes the actuating force parameter based on operational conditions. During normal operation, both clutches can be actuated simultaneously with full force. When a fault is detected, the control system modifies the actuating force parameter of the healthy clutch to ensure the total force does not exceed design limits, thus protecting components while maintaining productivity.
2Reliability
If the total actuating force is limited during fault conditions, then component damage is prevented, but the double clutch can only operate with one individual clutch, reducing productivity
Solution Approach 1:
When a fault is detected in one clutch, the system extracts or removes the faulty clutch from active operation by limiting its actuating force to zero or minimal values. The healthy clutch continues to operate independently with limited total force, allowing the system to maintain basic functionality and reach home position while protecting components from damage.
Solution Approach 2:
The system applies partial action by allowing only one clutch to be actuated during fault conditions rather than both. This partial operation is sufficient to complete the shifting sequence and reach the home position, maintaining essential productivity while preventing excessive total force that would damage components.
3Reliability
If pressure sensors are installed in each clutch actuator to detect faults, then fault detection capability is improved, but the device complexity increases
Solution Approach 1:
The clutch actuators perform self-service by incorporating pressure sensors that automatically monitor their own operating conditions. Each actuator detects its own fault status and communicates this information to the control system, enabling autonomous fault detection without requiring external monitoring equipment, thus improving reliability with minimal added complexity.
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 reduces component stress and manufacturing costs, allows for safe operation during faults, and ensures smooth limp-home functionality by limiting total actuating forces and engine torque, thereby preventing damage and maintaining vehicle operation.
Implementation Method 1
each having a pressure sensor that senses the working pressures of the respective clutch actuator
Implementation Method 2
a hydrostatic actuating system that includes two clutch actuators assigned to two individual clutches
Data Source
AI summary
A method of operating a double clutch that is actuated by a hydrostatic actuating system having two clutch actuators assigned to two individual clutches and each clutch actuator including a pressure sensor for sensing the operating pressure of the respective clutch actuator, the method having the step of limiting a total actuating force of the double clutch in the event of a fault using the pressure values sensed by the pressure sensors.