Hybrid Clutch Torque Control via Engine Speed Feedback
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Solution Overview
Problem
In hybrid electric vehicles, existing clutch torque control systems cause discomfort due to irregular engine rotation during start-up and low-speed driving, as the slip amount and friction coefficient changes lead to torque vibrations and discomfort for the driver.
Innovation Solution
A clutch torque control system that controls the slip amount to maintain a small value during half-clutch engagement, ensuring the engine rotational speed is within a range that provides sufficient torque, thereby reducing the change in friction coefficient and achieving smooth acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the clutch is controlled in a half-clutch state during start-up or low-speed driving, then the irregular engine rotation can be reduced, but the change in friction coefficient causes torque vibration and driver discomfort
Solution Approach 1:
The invention changes the control parameter from slip amount to engine rotational speed. By controlling the engine rotational speed to be within a specific range (above a predetermined threshold) during half-clutch engagement, the friction coefficient change is minimized, thereby reducing torque vibration while maintaining stable engine rotation.
Solution Approach 2:
The invention implements feedback control by continuously monitoring the engine rotational speed and adjusting the engine output torque accordingly. The control unit compares the actual engine rotational speed with the target range and modifies the engine torque to maintain the speed within the predetermined range, ensuring stable friction coefficient and smooth torque transmission.
2Object-affected harmful factors
If the slip amount is reduced to minimize friction coefficient change, then torque vibration is reduced, but the engine may not provide sufficient torque during acceleration
Solution Approach 1:
The invention identifies a specific engine rotational speed range that simultaneously satisfies two conditions: (1) the friction coefficient change is minimized, and (2) the engine can deliver sufficient torque. By controlling the engine speed to stay above a predetermined threshold within this range, both torque vibration reduction and adequate power delivery are achieved.
Solution Approach 2:
The invention dynamically adjusts the engine output torque based on the required acceleration while maintaining the engine rotational speed within the optimal range. The control system modulates the engine torque in real-time to ensure sufficient power delivery during acceleration without allowing the speed to drop into the range that would cause excessive friction coefficient change.
3Device complexity
If conventional clutches are used without optimized control, then the system is simpler, but acceleration smoothness deteriorates due to friction coefficient changes
Solution Approach 1:
The invention utilizes the engine's own rotational speed as the control parameter, which is already available in the engine control system. By leveraging existing sensors and control capabilities, the system achieves smooth acceleration without requiring additional hardware or complex control mechanisms, thus maintaining simplicity while improving 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
The system ensures smooth acceleration and improved driving performance by minimizing torque changes and preventing acceleration failures, providing comfort to the driver and allowing the use of clutches with inferior characteristics, thus reducing manufacturing costs.
Implementation Method 1
a change in the slip amount (Δn) causes a change in friction coefficient (μ) of the clutch, and that accordingly the transfer torque is changed
Data Source
AI summary
The present invention provides a clutch torque control system of a hybrid electric vehicle, which performs an engine rotational speed control in a power generation system including an engine, a motor-generator, and a clutch for controlling connection and disconnection between the engine and the motor-generator.