CVVD and CVVT Valve Timing Control via Segmentation
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Solution Overview
Problem
Existing systems for controlling valve timing in continuous variable valve duration engines fail to simultaneously optimize the duration and timing of intake and exhaust valves, leading to suboptimal engine performance, fuel efficiency, and increased emissions.
Innovation Solution
A system and method that independently control the opening and closing timings of intake and exhaust valves using a combination of continuous variable valve duration (CVVD) and continuous variable valve timing (CVVT) devices, with a controller determining target timings and performing feedback control based on vehicle state data and camshaft position, to optimize valve operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If CVVD device controls valve opening period with fixed peak lift timing, then valve duration is adjusted, but valve timing cannot be optimized simultaneously
Solution Approach 1:
The patent divides the valve control function into two independent devices: CVVD device for controlling opening period (duration) and CVVT device for controlling opening/closing timing. This segmentation allows each device to optimize its specific function without interfering with the other, resolving the contradiction between duration control and timing flexibility.
Solution Approach 2:
The patent implements dynamic control where the CVVT device can advance or delay the valve opening timing independently while the CVVD device maintains the optimal opening period. This dynamic adjustment capability allows the system to adapt to different operating conditions, simultaneously optimizing both duration and timing.
2Productivity
If both CVVD and CVVT devices are used to control valve duration and timing, then valve operation is optimized, but system complexity increases
Solution Approach 1:
The patent merges the CVVD and CVVT devices into a coordinated control system where both devices work together to achieve optimal valve operation. The controller integrates signals from both devices and adjusts them cooperatively, achieving enhanced engine performance while managing system complexity through unified control architecture.
Solution Approach 2:
The patent implements feedback control where the controller continuously monitors engine operating conditions and adjusts both CVVD and CVVT devices based on real-time data. This feedback mechanism allows the system to automatically optimize valve duration and timing while adapting to changing conditions, managing complexity through intelligent control.
3Productivity
If valve timing is not simultaneously optimized, then engine performance is compromised, but control system becomes simpler
Solution Approach 1:
The patent segments the control functions into dedicated CVVD and CVVT devices, each responsible for specific aspects of valve operation. This segmentation enables simultaneous optimization of both duration and timing, improving fuel efficiency while keeping the control mechanism organized and manageable through functional separation.
Data Source
AI summary
A method for controlling valve timing of continuous variable valve duration engine may include continuous variable valve duration (CVVD) device and continuous variable valve timing (CVVT) device including determining target intake valve open (IVO) timing, target intake valve close (IVC) timing, target exhaust valve open (EVO) timing and target exhaust valve close (EVC) timing; determining target intake CVVD, target exhaust CVVD, target intake CVVT and target exhaust CVVT to satisfy the target IVO, IVC, EVO, and EVC timings; performing feedback control of the CVVD by learning minimum value of the CVVD and maximum value of the CVVD; performing feedback control of the CVVT based on profile information of the valve; and determining real IVO timing, real IVC timing, real EVO timing, and real EVC timing based on the feedback control of the CVVD and the feedback control of the CVVT.