Turbo Engine Valve Timing Control via CVVD and CVVT
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Solution Overview
Problem
Existing engine technologies face challenges in simultaneously controlling the duration and timing of intake and exhaust valves in turbo engines, which affects engine performance and efficiency, especially under varying load and speed conditions.
Innovation Solution
A system and method that classify engine operation into multiple control regions based on speed and load to independently control the opening and closing timing of intake and exhaust valves using a combination of continuous variable valve duration (CVVD) and continuous variable valve timing (CVVT) devices, optimizing valve timing and duration for improved performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If both CVVD device and CVVT device are combined to control valve duration and timing, then valve control precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the valve control system into independent CVVD and CVVT devices for intake and exhaust valves, allowing separate optimization of duration and timing control for each valve, thereby achieving precise control while managing complexity through modular architecture
Solution Approach 2:
The system dynamically adjusts valve duration and timing based on real-time engine operating conditions (load, speed, temperature) using multiple control maps, enabling the CVVD and CVVT devices to adapt their control parameters continuously for optimal performance
2Productivity
If valve duration and timing are simultaneously controlled under varying engine conditions, then engine performance is improved, but control system complexity increases
Solution Approach 1:
The patent employs multiple control maps with different parameter sets for various engine operating conditions (different load ranges, speed ranges, and temperature conditions). The control system selects appropriate parameter sets by changing operating parameters, enabling optimized valve control for each condition without requiring a single complex control algorithm
Solution Approach 2:
The system uses feedback from engine operating parameters (load sensor, speed sensor, temperature sensor) to dynamically select appropriate control parameters from predefined maps, creating a closed-loop control system that adapts valve timing and duration to actual operating conditions
3Use of energy by moving object
If maximum duration is applied to intake valve in low load conditions, then fuel efficiency is improved, but valve overlap control becomes difficult
Solution Approach 1:
The patent applies different control strategies to intake and exhaust valves independently, and different strategies for different operating conditions. In low load conditions, maximum duration is applied to intake valve while exhaust valve timing is adjusted to maintain proper overlap, achieving fuel efficiency without compromising exhaust control
Data Source
AI summary
A method for controlling valve timing of a turbo engine may include: classifying by a controller control regions depending on an engine speed and an engine load, and the control regions may include first, second, third, fourth, fifth, and sixth control regions. The method further includes: applying a maximum duration to an intake valve and controlling a valve overlap in the first control region; applying the maximum duration to the intake valve and exhaust valve in the second control region; advancing an intake valve closing (IVC) timing and an exhaust valve closing (EVC) timing in the third control region; approaching the IVC timing to a bottom dead center in a fourth control region; controlling a wide open throttle valve (WOT) in the fifth control region; and controlling the WOT and the IVC timing to reduce the knocking in the sixth control region.