CVVT Locking Pin Release Control via Alternating Cam Rotation
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Solution Overview
Problem
The continuous variable valve timing (CVVT) system experiences issues where the locking pin is not properly released from its hole, causing the cam to rotate in the opposite direction of the intended rotation, leading to engine malfunctions and requiring unnecessary repairs.
Innovation Solution
A method and system that alternately perform holding and rotation controls to prevent the cam from rotating in the opposite direction by searching the target rotation direction, removing friction forces, and gradually decreasing the duty value applied to the cam until the locking pin is released, ensuring the cam rotates in the intended direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the locking pin is released from the locking pin hole by moving it downward, then the locking pin can be freed from the hole, but the cam may rotate in the opposite direction causing shaking
Solution Approach 1:
The control method performs preliminary actions by alternately executing holding controls (stopping cam rotation) and rotation controls (rotating cam in target direction) before the locking pin is fully released. This preliminary alternating control prepares the system to prevent opposite-direction rotation that would cause shaking, ensuring stable operation from the outset of the release process.
Solution Approach 2:
The control method employs periodic action by alternately switching between holding controls and rotation controls at predetermined intervals during the locking pin release process. This periodic alternation continues until the locking pin is completely released, preventing the cam from rotating in the opposite direction and eliminating shaking while ensuring reliable release.
2Speed
If the cam is rotated in the target direction before the locking pin is fully released, then the cam can reach the target position, but the locking pin may be physically caught causing failure to release
Solution Approach 1:
The control method performs preliminary alternating holding and rotation controls before the locking pin is fully released. This preliminary action gradually prepares the system by intermittently rotating the cam in the target direction while stopping at intervals, allowing the locking pin to progressively release without being physically caught by peripheral devices or foreign materials.
Solution Approach 2:
The control method applies dynamics by making the cam rotation dynamic rather than continuous. The ECU alternately stops and rotates the cam in the target direction based on predetermined intervals, creating a dynamic control pattern that adapts to the locking pin's release status. This dynamic approach allows the cam to rotate at appropriate speeds while ensuring the locking pin releases reliably without physical catching.
3Reliability
If the locking pin is not released properly, then the system maintains its current state, but the engine warning light activates requiring unnecessary repairs
Solution Approach 1:
The control method performs preliminary alternating holding and rotation controls to ensure the locking pin is completely released before normal operation begins. By proactively managing the release process with predetermined interval alternation, the system prevents incomplete release scenarios that would trigger engine warning lights and require unnecessary repair visits.
Solution Approach 2:
The control method implements feedback by continuously monitoring whether the locking pin has been completely released and adjusting the alternating holding and rotation controls accordingly. The ECU determines based on feedback from the release process whether to continue alternating controls or transition to normal operation, ensuring reliable release and preventing false warning light activation that would lead to unnecessary repairs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents the CVVT system from shaking in the opposite direction during locking pin release, ensuring smooth operation and preventing engine warning lights from activating, thus reducing the need for unnecessary repairs and optimizing system performance.
Implementation Method 1
releasing the locking pin from a locking pin hole by an Electronic Control Unit (ECU) so that a catching phenomenon of the locking pin due to friction force
Implementation Method 2
a rotation control of the cam into a target direction so that it is prevented that the cam is rotated in a direction which is opposite to a rotation target direction of the cam
Data Source
AI summary
A method for releasing a catching of a locking pin may include a control application step of releasing the locking pin from a locking pin hole by an electronic control unit (ECU) so that a catching phenomenon of the locking pin due to friction force into a rotation direction of a cam is prevented, and a cam shaking prevention control logic alternately performing, by the ECU, a holding control stopping a rotation of the cam and a rotation control of the cam into a target direction so that it is prevented that the cam is rotated in a direction which is opposite to a rotation target direction of the cam when the releasing of the locking pin is completed.