Hybrid Vehicle Fail-Safe Control for Clutch Failure
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Solution Overview
Problem
Conventional hybrid vehicles face difficulties in maintaining the HEV mode when the second clutch fails, leading to a reduction in travel distance due to premature switching to the EV mode, which limits the cruisable distance based on battery capacity.
Innovation Solution
A fail-safe control device for hybrid vehicles that includes a clutch failure determination unit and a controller, which prohibits transitioning from the HEV mode to the EV mode when an ON-failure of the second clutch is detected, allowing the engine to continue driving and extending the travel distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle switches to EV mode when the second clutch fails, then the vehicle can continue traveling using battery power, but the cruisable distance becomes shorter because the vehicle is limited to EV mode only
Solution Approach 1:
Instead of switching to EV mode when the second clutch fails (conventional approach), the invention inverts the logic by prohibiting the transition from HEV to EV mode. This allows the vehicle to remain in HEV mode and continue using engine power, thereby extending the cruisable distance beyond what battery capacity alone would permit.
2Length of moving object
If the vehicle continues in HEV mode when the second clutch has failed, then the cruisable distance is extended by using engine power, but the vehicle cannot switch to EV mode which would be the normal fail-safe operation
Solution Approach 1:
The invention dynamically adjusts the mode switching behavior based on the failure condition. When an ON-failure of the second clutch is detected during HEV mode operation, the controller prohibits transition to EV mode, allowing the vehicle to adapt by continuing in HEV mode rather than following the standard mode switching protocol.
3Length of moving object
If the controller prohibits transition from HEV mode to EV mode when second clutch ON-failure is detected, then the travel distance is extended by utilizing engine power, but the system complexity increases due to failure detection and conditional control logic
Solution Approach 1:
The controller implements a feedback mechanism that monitors the operational status of the second clutch. When an ON-failure is detected during HEV mode operation, the feedback triggers a conditional response that prohibits mode transition, thereby extending travel distance while managing system complexity through intelligent control logic.
Data Source
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AI summary
The purpose of present invention is to provide a fail-safe control device for hybrid vehicles which allows the travel distance of a vehicle to be extended in the event of an ON-failure of a second clutch. An integrated controller (10) switches between an HEV mode and an EV mode by controlling a first clutch (CL1) between an engine (Eng) and a motor (MG), and a second clutch (CL2) between the motor (MG) and a continuously variable transmission (CVT). The integrated controller (10) prohibits the transition from the HEV mode to the EV mode when a clutch failure determination unit (30) detects an ON-failure of the second clutch (CL2) while the vehicle is traveling in the HEV mode.