Valve Timing Control Intermediate Lock Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing valve timing control devices face issues with maintaining or releasing the intermediate lock state, particularly during sudden increases in rotation speed or cold starts, leading to phase irregularity and performance problems in internal combustion engines.
Innovation Solution
A valve timing control device with a fluid pressure chamber, partitioned into retard and advance chambers, and an intermediate lock mechanism using concave portions and lock members, which can switch between lock and unlock states, controlled by a phase control unit to align with average torque and fluid pressure, and featuring thinned portions for reduced weight and enhanced shear retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lock members are always spring-biased toward engagement grooves to prevent escape, then reliability of intermediate lock state is improved, but device complexity increases due to additional spring mechanisms
Solution Approach 1:
The patent extracts the spring-biasing function from the lock mechanism and replaces it with a simplified geometry-based retention system. The lock members rely on their own geometric shape and the engagement groove design to maintain the locked state, eliminating the need for additional spring components while maintaining reliability.
Solution Approach 2:
The lock members are designed to be self-retaining through their geometric configuration. The engagement groove and lock member shapes are designed so that the lock members naturally maintain engagement without requiring external biasing forces from springs or other active retention mechanisms.
2Reliability
If lock members are made robust to withstand centrifugal forces, then reliability is improved, but weight increases which affects phase change speed
Solution Approach 1:
The lock members are designed with non-uniform cross-sections, having thicker regions at critical stress points to withstand centrifugal forces and thinner regions to minimize overall weight. This local variation in material distribution optimizes the strength-to-weight ratio for the specific loading conditions experienced during operation.
3Reliability
If intermediate lock mechanism is added to fix relative rotational phase, then reliability during starting is improved, but device complexity increases
Solution Approach 1:
The intermediate lock mechanism is integrated into the existing valve timing control device architecture by combining the lock members and engagement grooves with the hydraulic control system. This merging approach allows the lock function to be achieved without adding completely separate mechanical subsystems, thereby reducing overall device complexity.
4Use of energy by moving object
If hydraulic pressure control is delayed during cold start, then energy consumption is reduced, but manufacturing precision of phase control deteriorates
Solution Approach 1:
The intermediate lock mechanism establishes the correct relative rotational phase position before hydraulic pressure control begins during cold starts. This preliminary action of setting the phase mechanically ensures that when hydraulic control commences, the system starts from an accurate baseline position, maintaining phase control precision without requiring premature or excessive hydraulic energy consumption.
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
The solution ensures reliable retention of the intermediate lock state under centrifugal forces and facilitates rapid phase changes, improving engine performance by preventing lock member escape and ensuring precise ignition timing.
Implementation Method 1
a fluid pressure control unit controlling the supply of the fluid to the retard chamber and the discharge of the fluid from the advance chamber or the supply of the fluid to the advance chamber and the discharge of the fluid from the retard chamber so that the relative rotational phase changes
Implementation Method 2
the lock members are configured to be always spring-biased toward the engagement grooves
Implementation Method 3
the escape of the lock members from the engagement grooves based on a centrifugal force resulting from the rotation of the driving side rotating body and the driven side rotating body during the starting of the internal combustion engine
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
A valve timing control device includes: a driving side rotating body (1) rotating in synchronization with a crankshaft (EX); a driven side rotating body (2) rotating integrally with a camshaft (3) and capable of rotating relative to the driving side rotating body (1); a fluid pressure chamber (40) formed by the driving side rotating body (1) and the driven side rotating body (2); a partition portion (5) arranged in the fluid pressure chamber (40) and partitioned into a retard chamber (41) and an advance chamber (42); an intermediate lock mechanism including a concave portion (7) and a lock member (6); and a phase control unit controlling the supply of a fluid to the retard chamber (41) and the discharge of the fluid from the advance chamber (42) or the supply of the fluid to the advance chamber (42) and the discharge of the fluid from the retard chamber (41).