Hybrid Vehicle Clutch Torque Learning via HSG Power Redirection
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Solution Overview
Problem
Conventional hybrid vehicles lack technology to precisely estimate and control the transferring torque of the engine clutch, leading to drivability and mileage issues due to variations in component durability and inaccurate feed-forward elements in engine control.
Innovation Solution
A system and method that includes a controller to learn and estimate the transferring torque by measuring free-load and load torques, adjusting engine and motor RPMs, and redirecting charging power to a Hybrid Starter and Generator (HSG) when necessary, allowing for precise clutch control and energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional hybrid vehicles use basic torque estimation through effective pressure and frictional coefficient, then the system structure remains simple, but the measurement precision of transferring torque deteriorates due to component durability variations
Solution Approach 1:
The system performs preliminary learning of the transferring torque characteristic during normal operation before actual starting acceleration occurs. The controller accumulates data on the relationship between solenoid valve current/pressure and actual clutch torque transfer, building a lookup table or mathematical model in advance. This preliminary characterization enables accurate torque estimation during starting acceleration without requiring complex real-time measurements.
Solution Approach 2:
The system implements feedback by comparing the estimated transferring torque with actual torque transfer behavior during learning operations. The controller adjusts the feed-forward current/pressure commands based on the difference between expected and actual clutch engagement characteristics. This closed-loop learning process compensates for component durability variations and friction material degradation over time.
2Speed
If the hybrid vehicle uses inaccurate feed-forward elements in engine clutch control, then the device complexity remains low, but the starting acceleration response deteriorates
Solution Approach 1:
The controller pre-learns the optimal feed-forward current and pressure commands for the solenoid valve by analyzing actual clutch engagement behavior during normal operation. This preliminary characterization stored in memory enables rapid starting acceleration response without requiring complex real-time calculations or additional sensors.
Solution Approach 2:
The system performs self-learning and self-adjustment of the clutch control parameters without requiring external calibration equipment or manual intervention. The controller automatically updates the feed-forward elements based on observed clutch behavior, enabling the system to adapt to component aging and maintain optimal starting acceleration performance throughout its service life.
3Ease of operation
If precise pressure control is required for slip-controlling the engine clutch under extreme conditions, then the drivability improves, but the control system complexity increases
Solution Approach 1:
The system uses feedback from the learned transferring torque characteristics to adjust the solenoid valve pressure control during slip-controlled starting acceleration. The controller compares the estimated torque with target torque values and dynamically adjusts pressure commands to maintain optimal slip control, improving drivability under extreme conditions such as steep slopes or high temperatures.
Solution Approach 2:
The system dynamically changes the pressure control parameters based on learned clutch characteristics and current operating conditions. By adjusting pressure rise rate, target pressure levels, and hold pressure duration based on the learned model, the system achieves precise slip control without requiring additional hardware 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
Improves drivability and starting acceleration response, and enhances mileage by accurately learning and adapting to the transferring torque, regardless of component durability, even in extreme conditions.
Implementation Method 1
A transferring torque of the engine clutch refers to a torque transferred with friction surfaces to which both ends of the engine clutch are in contact physically
Data Source
AI summary
A system and method for learning a transferring torque for a hybrid vehicle includes: an engine and a motor connected through a clutch; a Hybrid Starter Generator (HSG) that is connected to the engine and is used to start the engine; and a controller for transferring a charging power by the motor to the HSG in a case where the charging power by the motor is greater than or equal to a chargeable power of the battery when the transferring torque is learned through the clutch.