CVVD Engine Valve Timing Control via Dynamic Duration Adjustment
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Solution Overview
Problem
Existing engine technologies face challenges in optimizing valve timing and duration control for continuous variable valve duration (CVVD) engines, particularly in managing valve overlap and maintaining efficient engine performance across varying load and speed conditions.
Innovation Solution
A system and method that classify engine operating regions based on speed and load to control valve timing and duration, using a CVVD device on both intake and exhaust valves, applying maximum duration, adjusting closing timings, and managing manifold absolute pressure to optimize engine performance and reduce fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If valve duration is extended to improve fuel efficiency under partial load conditions, then fuel consumption is reduced, but valve overlap increases which can harm engine performance
Solution Approach 1:
The patent implements dynamic control of valve duration and valve overlap through the CVVD device, allowing the system to adjust valve timing parameters in real-time based on operating conditions. The controller dynamically modifies the duration that both intake and exhaust valves remain open, enabling optimization of fuel efficiency while preventing excessive valve overlap that would harm engine performance.
Solution Approach 2:
The system changes the timing parameters of valve operation by adjusting the duration that intake and exhaust valves remain simultaneously open. By controlling the valve overlap duration parameter within specific ranges (e.g., 30-60 degrees crank angle), the system achieves improved fuel efficiency under partial load while maintaining engine performance across different operating conditions.
2Power
If valve timing is optimized for high load conditions to enhance engine performance, then power output is improved, but fuel consumption increases
Solution Approach 1:
The CVVD device enables dynamic adjustment of valve timing parameters based on real-time operating conditions. Under high load conditions, the controller optimizes valve duration and overlap to maximize power output, while under partial load conditions, it adjusts parameters to reduce fuel consumption. This dynamic adaptation allows the system to achieve both high performance and fuel efficiency across different operating regimes.
Solution Approach 2:
The system modifies valve operation parameters including duration and timing based on load conditions. By controlling the valve overlap duration within optimal ranges and adjusting when valves remain open simultaneously, the system achieves improved fuel efficiency under partial load while maintaining adequate power output under high load conditions.
3Use of energy by moving object
If intake valve closing timing is advanced to improve fuel efficiency, then fuel consumption is reduced, but engine performance under high load conditions deteriorates
Solution Approach 1:
The controller dynamically adjusts the intake valve closing timing based on operating conditions. Under partial load conditions, the system advances the intake valve closing timing to improve fuel efficiency. Under high load conditions, it retards the closing timing to maintain engine performance. This dynamic control is achieved through the CVVD device which modifies the duration the intake valve remains open.
Solution Approach 2:
The system changes the intake valve closing timing parameter in response to load conditions. By controlling how long the intake valve remains open relative to the exhaust valve, the system achieves improved fuel efficiency under partial load while maintaining adequate power output under high load conditions through parameter optimization.
4Use of energy by moving object
If exhaust valve closing timing is delayed to extend valve duration for fuel efficiency, then fuel consumption is reduced, but valve overlap becomes excessive which harms combustion stability
Solution Approach 1:
The CVVD device enables dynamic control of exhaust valve closing timing to optimize fuel efficiency while maintaining combustion stability. The controller adjusts the duration the exhaust valve remains open based on operating conditions, ensuring that valve overlap does not exceed harmful thresholds that would compromise combustion stability, while still achieving fuel efficiency improvements under partial load conditions.
Solution Approach 2:
The system modifies the exhaust valve closing timing parameter to control valve overlap duration. By optimizing how long the exhaust valve remains open simultaneously with the intake valve, the system achieves improved fuel efficiency while preventing excessive valve overlap that would harm combustion stability and engine reliability.
Data Source
AI summary
A method for controlling valve timing is provided for an engine including continuous variable duration (CVVD) device disposed on both intake valve and exhaust valve sides respectively. The method may include: classifying control regions into first, second, third, fourth, and fifth control regions based on engine load and speed; applying a maximum duration to an intake valve and controlling a valve overlap in a first control region, applying the maximum duration to the intake valve and exhaust valve in the second control region; controlling a manifold absolute pressure (MAP) of an intake manifold to be maintained consistently in the third control region; controlling a throttle valve to be fully opened, advancing an intake valve closing (IVC) timing, and controlling an exhaust valve closing (EVC) timing to after top dead center in the fourth control region; and controlling a wide open throttle valve (WOT) and retarding the intake valve closing in the fifth control region.