Hybrid Engine Clutch Actuator Fail-Safe Control
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Solution Overview
Problem
The engine clutch actuator in hybrid vehicles lacks a fail-safe strategy, making it difficult to switch from electric vehicle (EV) mode to hybrid electric vehicle (HEV) mode when it fails, leading to increased power consumption and reduced fuel efficiency in EV mode.
Innovation Solution
A fail-safe control method that measures oil pressure in the engine clutch actuator's cylinder, compares it to a stored average pressure value, and adjusts the oil pressure using a motor to connect or disconnect the engine clutch, allowing the vehicle to switch from EV mode to HEV mode even if the actuator is malfunctioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine clutch actuator operates as a normally closed type clutch in EV mode, then the motor can be used as the main power source, but when the actuator fails, the rectilinear movement of the piston ceases and the vehicle cannot switch to HEV mode
Solution Approach 1:
The patent inverts the normal clutch operation logic by implementing a fail-safe mechanism where the clutch is designed to automatically engage (connect) when pressure is lost or the actuator fails, rather than requiring active control to maintain engagement. This inversion ensures that failure modes naturally lead to the safe state of engine connection, enabling automatic HEV mode transition.
Solution Approach 2:
The patent changes the pressure parameter state to control clutch engagement. By monitoring cylinder pressure and comparing it with reference values, the system detects actuator failure conditions and triggers mode switching. The pressure parameter serves as both the control variable for normal operation and the detection variable for fail-safe operation.
2Productivity
If the EV mode is forced to operate when the engine clutch actuator fails, then the vehicle continues to run, but power consumption increases and fuel efficiency deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors clutch operation status and actuator performance. When failure is detected through pressure monitoring or operational anomalies, the system provides feedback to automatically switch from EV mode to HEV mode, thereby adjusting energy usage in response to the failure condition and preventing excessive power consumption.
3Reliability
If the engine clutch actuator is designed with additional fail-safe strategies, then the mode switching capability is improved, but the device complexity increases
Solution Approach 1:
The patent makes the existing pressure sensor and control unit serve multiple functions: they continue to monitor pressure for normal clutch operation while simultaneously detecting fail-safe conditions and triggering mode switching. This multi-functionality approach adds reliability without requiring separate dedicated fail-safe sensors or actuators, thereby avoiding significant complexity increases.
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
Enables the hybrid vehicle to switch from EV mode to HEV mode when the engine clutch actuator fails, reducing power consumption and improving fuel efficiency by maintaining the vehicle in EV mode and ensuring a simple structural fail-safe control.
Implementation Method 1
an oil pressure in a cylinder of the engine clutch actuator is measured
Implementation Method 2
A motor of the engine clutch actuator rotates to decrease the oil pressure value in the cylinder
Implementation Method 3
transfers hydraulic pressure required for coupling or releasing the engine clutch by converting the torque generated from the motor into rectilinear movement
Data Source
AI summary
A fail-safe control method and apparatus for an engine clutch actuator includes determining whether a driving mode of a hybrid vehicle is an electric vehicle (EV) mode. An oil pressure in a cylinder of the engine clutch actuator is measured when the driving mode of the hybrid vehicle is the EV mode. The oil pressure value in the cylinder is compared with a previously stored average pressure value. A motor of the engine clutch actuator rotates to decrease the oil pressure value in the cylinder t when the oil pressure value in the cylinder is greater than the previously stored average pressure value. An engine clutch is connected to an internal combustion engine as the oil pressure value in the cylinder decreases.