CVVD Valve Timing Control for Engine Load Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing engine technologies face challenges in efficiently controlling valve timing and duration to optimize engine performance across varying engine speeds and loads, particularly in turbo engines, which affects fuel efficiency and power performance.
Innovation Solution
A system and method that utilize continuous variable valve duration (CVVD) devices on both intake and exhaust valves, controlled by a controller to adjust opening and closing timings based on engine speed and load, allowing for advanced or retarded timing adjustments to match target durations, thereby optimizing valve operation across different engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous variable valve duration devices are mounted on intake and exhaust valves to control valve timing and duration, then fuel efficiency under partial load conditions improves and power performance under high load conditions enhances, but device complexity increases
Solution Approach 1:
The system divides the valve timing control into separate intake and exhaust CVVD devices, allowing independent optimization of each valve's timing. This segmentation enables the intake valve to be optimized for fuel efficiency during partial load while the exhaust valve is optimized for power performance during high load conditions, resolving the contradiction between improved productivity and increased device complexity
Solution Approach 2:
The continuous variable valve duration devices enable dynamic adjustment of valve timing and duration based on real-time engine operating conditions. The system transitions from fixed valve timing to variable timing that adapts to changing load and speed conditions, allowing the engine to operate at optimal efficiency across different regimes while managing the complexity through automated control
2Use of energy by moving object
If valve opening duration is extended to improve fuel efficiency under partial load, then fuel consumption decreases, but combustion stability may be affected
Solution Approach 1:
The system applies different valve timing strategies to different valves based on local engine conditions. During partial load conditions, the intake valve uses extended opening duration to improve fuel efficiency, while the exhaust valve timing is independently optimized to maintain combustion stability. This local optimization allows fuel consumption reduction without compromising overall combustion reliability
Solution Approach 2:
The control system continuously monitors engine operating conditions and adjusts valve timing accordingly. Feedback from sensors monitoring combustion quality, load, and speed allows the system to extend intake valve duration for fuel efficiency while automatically adjusting exhaust valve timing to maintain combustion stability, resolving the contradiction between energy efficiency and reliability
3Power
If exhaust valve closing timing is retarded to enhance power performance under high load, then power output increases, but catalyst heating time is extended
Solution Approach 1:
The independent control of exhaust valve timing allows the system to optimize for power output during high load conditions while managing catalyst heating time separately. The exhaust CVVD device can retard closing timing to enhance power performance when needed, while the control system coordinates this with other engine parameters to minimize the impact on catalyst heating time
Solution Approach 2:
The system uses periodic adjustment of exhaust valve timing based on engine operating cycles. During high load conditions requiring power output, the timing is retarded periodically, while during lower load conditions the timing is advanced to reduce catalyst heating time. This periodic optimization balances power performance requirements with emissions control needs
Data Source
AI summary
A method for controlling intake and exhaust valves of an engine may include: determining, by a controller, a target opening duration of the intake and exhaust valves based on an engine load and an engine speed; modifying, by an intake continuous variable valve duration (CVVD) device and by an exhaust CVVD device, current opening and closing timings of the intake valve and/or exhaust valve based on the target opening duration of the valves; and advancing or retarding, by the intake and/or exhaust CVVD devices, the current opening timing of the intake and exhaust valves while simultaneously retarding or advancing the current closing timing of the intake and exhaust valve by a predetermined value based on the target opening duration.