Variable Valve Actuator Fixation Detection Control
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Solution Overview
Problem
Existing variable valve actuation systems for internal combustion engines face challenges in promptly determining actuator movement fixation, especially when the movement position is unknown, leading to inefficiencies and potential false learning of reference positions.
Innovation Solution
A control method that sends two distinct movement commands, A and B, to determine actuator fixation by assessing movement responses, allowing for rapid fixation detection and enabling faster learning of reference positions to initiate valve characteristic control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator is driven to determine fixation when movement position is unknown, then fixation detection can be performed, but the process requires driving to both high end and low end which consumes time
Solution Approach 1:
The patent applies preliminary action by first driving the actuator to the high end to establish a reference position before performing fixation detection. This preliminary positioning action enables subsequent detection to be performed more efficiently without requiring full traversal to both ends, thus reducing time while maintaining detection accuracy.
2Manufacturing precision
If the actuator movement range is mechanically restricted by stoppers, then the movement range is clearly defined, but false learning of reference positions may occur due to fixation
Solution Approach 1:
The patent implements feedback by continuously monitoring the actuator's movement amount and comparing it against expected values during the learning process. When the actuator approaches the high end stopper, the system detects the movement amount and uses this feedback to confirm proper positioning. This feedback mechanism prevents false learning by verifying that the actuator actually reached the intended reference position rather than being stopped by fixation.
3Productivity
If the electronic control unit drives the actuator to learn reference positions, then the valve angle-of-action control can be initiated, but the process is delayed when fixation is present
Solution Approach 1:
The patent applies preliminary action by performing a quick assessment drive to the high end before initiating full reference position learning. This preliminary action serves two purposes: it establishes the high end reference position quickly and simultaneously checks for fixation. By combining these functions in a preliminary step, the system avoids time delays during the main learning process when fixation is present.
Data Source
AI summary
In a variable valve actuation system capable of changing the angle of action of intake valves by using an actuator whose movement range is between a high end and a low end at which the movement of the actuator is mechanically stopped, it is determined that a fixation is present on condition that the actual amount of movement of the actuator in response to a command A for movement toward the low end that is issued when the present movement position of the actuator is unknown is not more than a prescribed movement criterion value a and that the actual amount of movement in response to a command B output subsequently to the command A in order to cause the actuator to operate in a direction opposite to the direction of the movement in response to the command B is not more than a prescribed movement criterion value b.