Engine Valve Timing and Duration Control via CVVD and CVVT
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Solution Overview
Problem
Existing engine technologies fail to optimally control the valve opening and closing timing and duration for both intake and exhaust valves, leading to suboptimal engine performance and efficiency across varying driving conditions.
Innovation Solution
A control method that simultaneously controls the duration and timing of valve opening and closing using a combination of continuous variable valve duration (CVVD) and continuous variable valve timing (CVVT) apparatuses, adjusting based on predetermined driving condition regions to optimize valve operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed valve duration and timing are used, then the device complexity is reduced, but engine performance and efficiency deteriorate across varying driving conditions
Solution Approach 1:
The patent implements dynamic valve control by enabling continuous adjustment of both valve duration (via CVVD apparatus) and valve timing (via CVVT apparatus). This allows the system to adapt valve operations to varying driving conditions, transforming the static valve control system into a dynamic one that optimizes engine performance across different operating regimes.
2Loss of energy
If simultaneous control of duration and timing is implemented, then engine efficiency improves, but device complexity increases
Solution Approach 1:
The patent combines CVVD (continuous variable valve duration) and CVVT (continuous variable valve timing) apparatuses into an integrated valve control system. This merging allows simultaneous control of both valve duration and timing parameters, enabling the system to reduce pumping loss and improve energy efficiency while managing complexity through integrated control architecture.
3Force
If valve timing is advanced, then low-end torque improves, but high-speed performance may deteriorate
Solution Approach 1:
The patent uses dynamic timing adjustment via the CVVT apparatus to optimize valve opening and closing timing based on real-time driving conditions. This allows the system to advance timing for low-end torque improvement when needed, and retard timing for high-speed performance optimization, dynamically balancing the trade-off between these conflicting requirements.
Solution Approach 2:
The patent changes the timing parameter continuously through the CVVT apparatus, allowing the valve timing to be adjusted across a wide range depending on operating conditions. This parameter change capability enables the system to optimize for low-end torque by advancing timing, and for high-speed performance by retarding timing, resolving the contradiction between these opposing performance requirements.
Data Source
AI summary
A control method controlling valve opening and closing for an engine including an intake CVVD apparatus, an intake CVVT apparatus, an exhaust CVVD apparatus, and an exhaust CVVT apparatus is disclosed. The control method includes determining, by a controller, a driving condition region among a predetermined plurality of driving condition regions of the engine defined based on a speed and a torque of the engine, and controlling, by the controller, opening timing and closing timing of each intake valve and exhaust valve wherein the driving condition region of the engine corresponds to a predetermined low torque region, the controller outputs a control signal so that an intake valve closing (IVC) timing is before bottom dead center, and an exhaust valve opening (EVO) timing is before the bottom dead center.