Automatic Clutch Control for Smooth Speed Synchronization
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Solution Overview
Problem
Existing clutch control methods fail to effectively manage engine and primary shaft speed synchronization during various driving situations, leading to abnormally long slip phases and potential jerks, especially when transitioning from freewheel or electrical to thermal operation, without guaranteeing convergence of engine and primary shaft speeds.
Innovation Solution
A control method that involves a first phase where the clutch remains open until the engine speed exceeds the primary shaft speed, followed by a second phase where the clutch torque is regulated based on the engine speed to facilitate convergence, and a third phase where the clutch is fully engaged to match the driver's torque request, ensuring smooth synchronization without jerks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the clutch is engaged rapidly to meet driver torque demand, then the response time is improved, but jerking occurs and driving comfort deteriorates
Solution Approach 1:
The clutch engagement process is divided into multiple phases: a first phase where the clutch is held open while engine speed increases, and a second phase where clutch torque is progressively applied. This segmentation allows the system to avoid rapid engagement jerks while still meeting driver torque demands, as the clutch torque is applied gradually rather than abruptly.
Solution Approach 2:
Before engaging the clutch, the engine speed is preliminarily increased to a value greater than the primary shaft speed during the first phase. This preliminary action ensures that when clutch engagement begins, the speed difference is minimized, reducing the risk of jerking while still allowing rapid overall response to driver torque demand.
2Object-generated harmful factors
If the clutch engagement is delayed to prevent jerking, then driving comfort is improved, but slip duration increases and energy is dissipated
Solution Approach 1:
The clutch torque setpoint is dynamically adjusted based on real-time speed measurements. During the second phase, the clutch torque is progressively increased as the engine speed approaches the primary shaft speed, optimizing the balance between preventing jerks and minimizing slip duration. This dynamic control reduces energy dissipation compared to fixed-delay engagement strategies.
Solution Approach 2:
The control system continuously monitors engine speed and primary shaft speed to determine when to transition from the first phase to the second phase. This feedback mechanism ensures clutch engagement begins at the optimal moment - when engine speed has sufficiently increased but before excessive slip occurs - thereby minimizing energy dissipation while preventing jerks.
3Manufacturing precision
If the clutch control system uses complex estimators and parameterization to optimize engagement, then synchronization precision is improved, but device complexity increases
Solution Approach 1:
The invention replaces complex, expensive estimators and parameterized models with a simpler control approach that uses direct speed measurements and predefined phase transitions. This simpler 'disposable' control logic achieves sufficient synchronization precision without the computational burden and complexity of advanced estimators, making the system more practical for real-world implementation.
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling an automatic clutch, during which an engine torque setpoint (6) is based on a driver's torque request and during which the clutch is regulated as a function of the variation in engine speed (2) which derives from this engine torque setpoint (6), and during which the clutch is started to be engaged only after the engine speed (2) has a value greater than that of a primary shaft speed (4) or greater than a predetermined threshold value.