Continuously Variable Valve Lift Mechanism Limp Mode Control
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Solution Overview
Problem
The continuously variable valve lift mechanism in vehicles often fails due to electronic control component failures or electric motor phase failures, leading to disabled automatic valve lift changing functions, which prevents smooth starting and operation, especially during cold starts, and requires trailer assistance for maintenance, affecting efficiency.
Innovation Solution
A control method and system that force the mechanism into a limp mode, move it to a maximum lift position, and self-lock it there, ensuring the vehicle can start and travel by aligning the resultant force of the roller assembly with the eccentric wheel's axis, enabling self-locking and smooth engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a continuously variable valve lift mechanism with electronic control components is used to improve engine efficiency, then engine efficiency is improved, but the risk of electronic control component failure increases
Solution Approach 1:
The patent designs a limp mode entry mechanism that activates beforehand when electronic control component failures are detected. This prior cushioning ensures that when failure occurs, the system can smoothly transition to a safe operational state (limp mode) rather than completely failing, thus maintaining reliability while preserving the efficiency benefits of the CVVL mechanism during normal operation.
2Extent of automation
If the continuously variable valve lift mechanism is designed with many electronic control components to enable automatic valve lift changing, then automatic valve lift changing function is improved, but the complexity of the system increases
Solution Approach 1:
The patent extracts the essential function of valve lift control from the complex electronic control system and implements a mechanical self-locking mechanism at the maximum lift position. This separation allows the electronic control components to be minimized or removed while retaining the core automatic valve lift changing function through the limp mode and self-locking design, thus reducing system complexity.
3Reliability
If the continuously variable valve lift mechanism fails and disables automatic valve lift changing function, then the mechanism requires trailer assistance for maintenance, but this affects maintenance efficiency
Solution Approach 1:
The patent implements a self-locking function that automatically locks the valve lift mechanism at the maximum lift position when failure occurs. This self-service capability allows the vehicle to remain operational and drive to a maintenance center without requiring external assistance, thus reducing maintenance time and improving overall maintenance efficiency.
4Reliability
If the valve lift mechanism is forced to move to maximum lift position and self-locked, then the vehicle can start and travel smoothly, but the valve lift is fixed and cannot be adjusted
Solution Approach 1:
The patent creates a dynamic system where the valve lift mechanism operates in two states: normal automatic adjustment mode when electronic controls are functional, and fixed limp mode at maximum lift when failures occur. This dynamic adaptability ensures the system can switch between full functionality and a safe limited state, maintaining vehicle startability while preserving adjustability during normal operation.
Data Source
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AI summary
A control method for a continuously variable valve lift mechanism includes: controlling a continuously variable valve lift mechanism (100) to enter a limp mode when the continuously variable valve lift mechanism (100) fails and disables an automatic valve lift changing function; driving and forcing the continuously variable valve lift mechanism (100) to move to a maximum lift position; and triggering a self locking function to self lock the continuously variable valve lift mechanism (100) at the maximum lift position when the continuously variable valve lift mechanism (100) reaches the maximum lift position. A control system for a continuously variable valve lift mechanism, a vehicle, an apparatus and a nonvolatile computer storage medium are also provided. With the control method for the continuously variable valve lift mechanism, a vehicle may be guaranteed to be started and travel smoothly when the continuously variable valve lift mechanism fails and disables the automatic valve lift changing function.