CVVT System Lock Pin Control for Engine Stability
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Solution Overview
Problem
Existing CVVT systems face issues with engine stability and fuel efficiency, particularly when the valve timing reaches the most retarded position, leading to increased engine vibration, potential engine stoppages, and inadequate fuel efficiency, especially in inline 4 cylinder engines where the intermediate phase CVVT is not effectively applied.
Innovation Solution
A CVVT system with an improved hydraulic system that includes an oil control valve (OCV) and an actuator to control the supply of oil to lock pins, allowing for selective opening and closing of the oil supply unit, enabling the lock pins to be separated from their lock pin holes, and featuring lock pins with different lash lengths for varying locking speeds and fixing forces, enabling intermediate phase CVVT application in inline 4 cylinder engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the valve timing reaches the most retarded position to improve fuel efficiency, then fuel efficiency is improved, but engine stability deteriorates and vibration increases
Solution Approach 1:
The patent implements dynamic control of valve timing through a CVVT system that can adjust camshaft phase continuously. The system dynamically transitions between retarded timing for fuel efficiency and intermediate timing for stability, avoiding the fixed extreme retarded position while still achieving fuel efficiency improvements through optimized valve timing control.
Solution Approach 2:
The patent changes the valve timing parameter from a fixed most-retarded position to a dynamically adjustable range. By controlling the camshaft phase within an optimized range rather than fixing it at the extreme retarded position, the system achieves fuel efficiency improvement while maintaining engine stability through parameter optimization.
2Loss of energy
If the valve timing is fixed at the most retarded position for fuel efficiency, then fuel efficiency is improved, but the engine may stop and operational stability decreases
Solution Approach 1:
The patent implements dynamic valve timing control that prevents the camshaft from being fixed at the most retarded position. The CVVT system continuously adjusts the camshaft phase based on engine operating conditions, ensuring the valve timing remains within a safe operational range that maintains engine continuity while still achieving fuel efficiency improvements.
Solution Approach 2:
The patent employs feedback control through the CVVT system that monitors engine operating conditions and adjusts valve timing accordingly. This feedback mechanism prevents the system from reaching extreme retarded positions that could cause engine stoppage, while still optimizing fuel efficiency through controlled valve timing adjustments within safe operational limits.
3Measurement precision
If the lock pin is automatically locked into the lock pin hole during RPM reduction, then the CVVT can return to accurate position, but the valve timing cannot return to intermediate phase and surge tank vacuumization is affected
Solution Approach 1:
The patent implements dynamic control that prevents automatic locking of the lock pin during RPM reduction. The CVVT system maintains dynamic adjustability of the camshaft phase, allowing the valve timing to return to intermediate phases when needed, while still achieving accurate position control through continuous electronic control rather than mechanical locking.
Solution Approach 2:
The patent extracts or removes the automatic locking function during RPM reduction. By preventing the lock pin from automatically engaging with the lock pin hole during this phase, the system maintains the ability to dynamically adjust valve timing to intermediate positions, thereby preserving both position accuracy and timing versatility through electronic control.
4Adaptability or versatility
If excessive overlap of valve timing is generated between intake and exhaust valves, then the operational stability decreases, but the CVVT system cannot achieve desired valve timing control
Solution Approach 1:
The patent employs feedback control through the CVVT system that monitors valve timing positions and prevents excessive overlap between intake and exhaust valves. The ECU continuously adjusts the camshaft phase based on feedback from cam angle and crank angle sensors, ensuring valve timing remains within optimal ranges that maintain engine stability while achieving desired timing control versatility.
Solution Approach 2:
The patent optimizes the valve timing parameters by controlling the camshaft phase within specific ranges that prevent excessive overlap. Through parameter optimization and continuous adjustment of valve timing angles, the system achieves versatile timing control while maintaining engine operational stability by avoiding harmful parameter extremes.
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
This solution maintains engine stability during idling and starting, improves fuel efficiency by allowing LIVC (Lift Intake Valve Closing) and adjustable valve timing, extends engine lifespan, and enhances fuel efficiency by enabling free valve overlap settings.
Implementation Method 1
an OCV (200) supplying oil received from a cylinder block into a CVVT (100)
Implementation Method 2
an actuator (500) selectively opening or closing an oil supply unit (400) such that oil is supplied to a lock pin (300) and the lock pin (300) is separated from a lock pin hole (310)
Data Source
AI summary
The present disclosure provides a CVVT system including: an OCV supplying oil received from a cylinder block into a CVVT; an oil supply unit supplying oil from the OCV to a lock pin; and an actuator selectively opening or closing the oil supply unit such that oil is supplied to the lock pin and the lock pin is separated from a lock pin hole when the oil supply unit is opened.