Hybrid Engine Clutch Control via Integrated Starter-Generator Torque
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Solution Overview
Problem
In hybrid vehicles, the inaccurate calculation of clutch input torque during engine clutch release leads to torque cutoff differences and inefficient fuel consumption, particularly when transitioning from HEV mode to EV mode.
Innovation Solution
An engine clutch control apparatus and method that calculates clutch input torque based on the charge torque of an integrated starter-generator, using vehicle controllers to determine chargeable torque, engine target torque, and friction torque to adjust and release the engine clutch when the input torque is below a reference value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the engine clutch is released based on conventional clutch input torque calculation, then the clutch release control is simple, but the clutch input torque is inaccurate causing torque cutoff differences
Solution Approach 1:
The patent introduces an integrated starter-generator as an intermediary component between the engine and transmission system. This device enables bidirectional torque transfer and provides additional sensing capabilities, allowing for more accurate clutch input torque calculation without significantly increasing overall system complexity. The starter-generator acts as a mediator that facilitates precise torque measurement and control during clutch release operations.
Solution Approach 2:
The patent replaces conventional mechanical torque sensing methods with an electrical sensing approach using the integrated starter-generator. By utilizing electrical signals from the starter-generator to calculate clutch input torque, the system achieves higher measurement precision while reducing mechanical complexity in the torque sensing mechanism.
2Speed
If the engine clutch is released quickly to improve responsiveness, then drivability is improved, but torque cutoff differences occur due to inaccurate torque calculation
Solution Approach 1:
The patent implements a feedback control mechanism where the clutch release process is continuously monitored and adjusted based on real-time torque calculations from the integrated starter-generator. The controller receives feedback signals about clutch engagement state and torque levels, enabling rapid yet smooth clutch release by dynamically adjusting the release rate to maintain torque transfer reliability while improving responsiveness.
Solution Approach 2:
The patent employs dynamic control of the clutch release process, adjusting the release speed and torque characteristics in real-time based on operating conditions. The system transitions from static, predetermined release schedules to dynamic, condition-based control, allowing rapid clutch release when appropriate while maintaining smooth torque transfer through continuous adaptation to changing system states.
3Loss of energy
If the engine clutch remains engaged longer to ensure smooth torque transfer, then torque cutoff differences are minimized, but fuel consumption increases
Solution Approach 1:
The patent utilizes parameter changes in the integrated starter-generator operation to optimize clutch release timing and characteristics. By adjusting electrical parameters such as generator torque and rotational speed, the system achieves efficient clutch release that minimizes energy loss while maintaining smooth torque transfer. The ability to rapidly change operational parameters allows for optimized fuel consumption without compromising drivability.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and preparing the clutch release sequence based on predicted operating conditions. The controller anticipates upcoming clutch release events and pre-adjusts system parameters, allowing for timely and efficient clutch disengagement that reduces fuel consumption while ensuring smooth torque transfer when the clutch is released.
Data Source
AI summary
An engine clutch control apparatus of a hybrid vehicle is provided. The apparatus includes an engine clutch that is disposed between an engine and a drive motor to selectively connect the engine and the drive motor and an integrated starter-generator that is connected with the engine to start the engine or to generate electricity. A vehicle controller releases or couples the engine clutch to implement a driving mode and determines a chargeable torque and an engine target estimation torque based on a generator rotation speed of the integrated starter-generator. An engine target torque and a charge torque are set based on the chargeable torque and a clutch input torque is generated using at least one of the engine target torque, an engine friction torque, and the charge torque. The engine clutch is then released when the clutch input torque is less than a reference value.