Hybrid Vehicle Clutch Failure Detection via Torque Deviation
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Solution Overview
Problem
In hybrid vehicles, determining engagement failure of a clutch due to insufficient hydraulic pressure is challenging during wet start clutch control, as the rotation speed difference is also caused by the slip state of the clutch, making it difficult to distinguish between normal slip and engagement failure using only rotation speed difference, and requiring additional sensors for hydraulic pressure detection, which increases costs.
Innovation Solution
A failure determination device that includes an engine, motor, clutch, pressure adjusting mechanism, target torque capacity calculation, actual torque calculation, torque deviation calculation, and failure determining means to determine engagement failure based on torque deviation during wet start clutch control, allowing for early detection of clutch engagement failure without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotation speed difference is used to determine engagement failure, then engagement failure can be detected, but during wet start clutch control the rotation speed difference cannot distinguish between normal slip and engagement failure
Solution Approach 1:
The invention changes the detection parameter from rotation speed difference to torque deviation. By calculating the difference between target torque (based on accelerator opening) and actual torque (sum of engine and motor torque), the system can accurately detect engagement failure even during wet start clutch control when rotation speed difference is ambiguous.
2Measurement precision
If hydraulic pressure sensor or switch is provided to detect hydraulic pressure, then engagement failure determination can be made based on hydraulic pressure, but cost increases
Solution Approach 1:
The invention uses existing sensors (accelerator opening sensor, engine torque sensor, motor torque sensor) to calculate torque deviation, which serves as an indirect indicator of hydraulic pressure status. This self-service approach eliminates the need for dedicated hydraulic pressure sensors while maintaining accurate engagement failure detection.
3Ease of operation
If wet start clutch control is performed to enable smooth start and stop, then starting performance is improved, but engagement failure cannot be properly determined during this control
Solution Approach 1:
The invention dynamically adapts the detection method to the current operating condition. During wet start clutch control, the system uses torque deviation calculation instead of rotation speed difference monitoring. This dynamic switching of detection strategies maintains both smooth starting performance and reliable engagement failure determination.
Data Source
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AI summary
An integrated controller calculates required driving force on the basis of accelerator opening, calculates torque capacity of the clutch, required for transmitting the required driving force by the clutch, as target torque capacity, calculates actual torque of the engine and actual torque of the motor, calculates a torque deviation as a deviation between the target torque capacity and a sum of the actual torque of the engine and the actual torque of the motor, and determines occurrence of an engagement failure of the clutch when the torque deviation becomes greater than a first fault determination value during the wet start clutch control.