Vane Rotor Locking Control for Internal Combustion Engine
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Solution Overview
Problem
The existing valve timing control device for internal combustion engines faces challenges in smoothly engaging the lock pin with the lock hole when the engine is stopped, especially when the operation chambers are filled with hydraulic fluid, leading to a longer time to achieve the required angular position, which affects engine starting.
Innovation Solution
The device incorporates an annular housing with operation chambers, a vane rotor, lock members, and a communication passage that establishes communication between the chambers when the engine is stopped and reduces the passage area as the engine starts, allowing for efficient locking of the vane rotor at an intermediate angular position using a passage control mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lock pin engages with the lock hole when the operation chambers are filled with hydraulic fluid, then the vane rotor can be locked at the intermediate angular position, but the engagement takes a longer time and may fail to occur smoothly
Solution Approach 1:
The communication passage is opened in advance when the engine stops, allowing hydraulic fluid to equalize between the advancing and retarding operation chambers before the locking action is required. This preliminary fluid equalization ensures that when the lock pin engages the lock hole, the chambers are not under high pressure, enabling smooth and quick engagement without delay or failure.
2Ease of operation
If the communication passage between advancing and retarding operation chambers is open when the engine is stopped, then the hydraulic fluid can equalize and the lock pin can engage smoothly, but the passage area must be reduced when the engine starts to maintain proper hydraulic pressure
Solution Approach 1:
The communication passage is designed with variable cross-sectional area that dynamically changes based on engine operating conditions. When the engine stops, the passage has a larger cross-sectional area to allow free fluid equalization and smooth lock pin engagement. When the engine starts and reaches a predetermined speed, the passage area is reduced to maintain proper hydraulic pressure for normal operation. This dynamic adjustment is achieved through a passage control mechanism that responds to engine speed or pressure conditions.
3Stress or pressure
If the passage control mechanism reduces the cross sectional area of the communication passage when the engine reaches a predetermined speed, then hydraulic pressure is maintained for normal operation, but the mechanism adds complexity to the system
Solution Approach 1:
The communication passage's cross-sectional area is changed as a variable parameter in response to engine operating conditions. The passage control mechanism monitors engine speed or hydraulic pressure and adjusts the passage area accordingly. At low speeds or during stopping, the passage area is large to facilitate fluid equalization. At predetermined speeds during normal operation, the passage area is reduced to maintain adequate hydraulic pressure. This parameter change approach allows the system to optimize performance for different operating modes while managing the added complexity through a relatively simple control mechanism.
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
This solution ensures quick and smooth engagement of the vane rotor at the intermediate angular position, improving engine startability and reducing the risk of prolonged engine stall conditions by enhancing the reciprocative swing movement and hydraulic pressure control.
Implementation Method 1
a communication passage provided by one of the vane rotor and the annular housing to communicate the advancing and retarding operation chambers
Implementation Method 2
reduces a cross sectional area of the communication passage when, after starting of the engine, the engine comes to show a predetermined speed or higher
Implementation Method 3
the vane rotor being turned in an advancing or retarding direction relative to the annular housing when a hydraulic pressure is supplied to or discharged from the advancing and retarding operation chambers respectively
Data Source
AI summary
Even if an internal combustion engine is stopped having a lock pin of a vane rotor kept disengaged from a lock recess, subsequent engine starting can instantly move the vane rotor to a desired angular position where the lock member an be engaged with the lock recess. The vane rotor has therein two passage control mechanisms each having a hydraulically actuated valve body. When the valve body is moved to a given position, retarding and advancing hydraulic holes become communicated to each other through an annular groove of the valve body. Due to this ON communication, retarding and advancing operation chambers become communicated, so that reciprocative swing movement of the vane rotor induced by an alternating torque produced at the starting of the engine is effectively made and thus the vane rotor can be quickly turned to the desired angular position for ease of engine starting.