Variable Valve Control Apparatus Torque Fluctuation Compensation
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Solution Overview
Problem
Existing internal combustion engine valve systems with variable valve-characteristic mechanisms face challenges in accurately controlling valve characteristics, leading to unpredictable torque output changes that can perturb drivers, especially when learning a reference position for valve control.
Innovation Solution
A control apparatus and method that includes a controller to detect the operating position of the variable valve-characteristic mechanism, adjust the target valve characteristic, and use an intake-air-amount adjustment device to offset changes in intake air, minimizing torque output fluctuations during the learning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the target value of the valve characteristic is changed to learn the reference position, then the valve characteristic control accuracy is improved, but the amount of intake air changes causing torque output fluctuations that perturb the driver
Solution Approach 1:
The control apparatus applies preliminary anti-action by proactively adjusting the intake-air-amount adjustment device before the valve characteristic change completes. When the target valve characteristic value is changed during the learning process, the system simultaneously operates the intake-air-amount adjustment device in the opposite direction to compensate for the expected intake air change, thereby preventing torque output fluctuations before they occur.
Solution Approach 2:
The intake-air-amount adjustment device serves as an intermediary element between the valve characteristic change and the torque output. Instead of allowing the valve characteristic change to directly affect torque output, the intermediary device mediates by adjusting intake air amount to offset the change, thereby isolating the harmful effect from the driver.
2Manufacturing precision
If the reference position is learned by changing the target duration to the shortest duration, then the valve characteristic reference accuracy is improved, but the intake air amount decreases reducing engine output torque
Solution Approach 1:
The system applies parameter changes by dynamically adjusting multiple parameters simultaneously. When the target valve characteristic (duration) is changed to establish the reference position, the system concurrently changes the intake-air-amount adjustment device parameter to compensate for the intake air loss. This multi-parameter coordination allows the reference position to be learned accurately while maintaining the engine output torque.
Data Source
AI summary
In an control apparatus and a control method for an internal combustion engine with a variable valve-characteristic mechanism that changes a valve characteristic that includes at least one of the duration and the maximum lift of an intake valve, the operating position of the mechanism is detected, and the mechanism is controlled so that a value of the valve characteristic corresponding to the operating position is equal to a target value corresponding to an engine operating state. After the target value is changed so that the intake valve opens/closes in accordance with a specific value of the valve characteristic, the operating position of the mechanism is learned as a reference position for the control of the valve characteristic. An intake-air-amount adjustment device upstream of the intake valve is controlled to offset the change in the amount of intake air caused by changing the target value when the reference position is learned.