Vehicle Clutch Drive Unit Dither Control for Thermal Management
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Solution Overview
Problem
Existing vehicle clutch assembly control systems face overheating issues during high-stress conditions, leading to performance drops and potential system failures, which can impact driving comfort and dynamics.
Innovation Solution
A method involving a dither function is used to control the drive unit, ensuring continuous movement of the electric machine by loading multiple phases with current, thereby reducing the load on individual phases and preventing overheating, while maintaining constant torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the electronic control unit switches off the clutch assembly control during high-stress conditions to prevent overheating, then the temperature of the electronic control unit is reduced, but the driving performance and all-wheel drive operation are compromised
Solution Approach 1:
The clutch assembly is divided into multiple independent clutch packages (front and rear axles), each with separate electronic control units and servomotors. This segmentation allows selective control of individual axles, enabling the system to maintain all-wheel drive operation by controlling only the necessary axle rather than shutting down the entire system during thermal stress conditions
Solution Approach 2:
The electronic control unit dynamically adjusts the coupling torque distribution between front and rear axles based on real-time driving conditions and thermal states. By continuously varying the torque split ratio, the system can maintain optimal driving performance while managing heat generation in individual control units, avoiding complete system shutdown
2Reliability
If the electronic servomotor operates continuously under high load to maintain optimal driving dynamics, then the driving performance is improved, but the electronic servomotor overheats and may fail
Solution Approach 1:
The electronic control unit implements periodic modulation of the coupling torque, alternating between higher and lower torque demands on the electronically controlled axle. This periodic variation allows the servomotor to operate in pulses rather than continuous high-load mode, providing cooling intervals that prevent overheating while maintaining overall driving dynamics
Solution Approach 2:
The control unit changes operational parameters of the servomotor by adjusting the coupling torque ratio between axles. When thermal stress is detected, the system modifies the torque distribution parameter, reducing the load on the heated servomotor while compensating through the other axle, thereby preventing failure without significantly impacting driving performance
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 effectively delays or prevents overheating without compromising driving performance, ensuring consistent operation even in borderline situations.
Implementation Method 1
controlling the drive unit with a dither function, wherein a position of the drive unit is continuously varied about the first position
Implementation Method 2
In such an electronic servomotor, mechanical coupling generally results between the motor rotation angle (rotational motion) and the clutch displacement travel (translational motion)
Data Source
AI summary
Operating a drive train of a vehicle having a clutch assembly, wherein the clutch assembly is actuatable via an actuating device for the switchable transmission of a torque, wherein a first state of the actuating device, and thus a second state of the clutch assembly, is settable via a position of a drive unit of the actuating device, comprises:a) determining that a first torque request to the clutch assembly is constant; andb) determining that a first position of the drive unit is constant within the interval; and thenc) controlling the drive unit with a dither function, wherein a position of the drive unit is continuously varied about the first position; andd) ending the dither function when the conditions stated in steps a) and b) are no longer met.