Spool Valve Oil Passage Layout for Common VVT Switching Timing
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Solution Overview
Problem
The existing control valves for internal combustion engine valve timing control devices require different structures for valve timing advance and retard control, leading to increased costs due to the need for distinct components and different switching timings.
Innovation Solution
A spool valve design that allows for adjustable orientation to achieve commonality between valve timing control devices, where the spool valve's position and oil passages enable communication between retard and advance ports through various passages, allowing for shared components and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different structures are used for valve timing advance and retard control devices, then control responsiveness can be optimized for each direction, but manufacturing cost increases due to lack of component commonality
Solution Approach 1:
The spool valve is designed with multi-functionality to serve both valve timing advance and retard control devices. By configuring the spool valve with specific oil passages (first spool oil passage and second spool oil passage) and enabling it to travel in different directions, a single spool valve structure can achieve the functions previously requiring separate structures, thereby reducing manufacturing costs while maintaining control responsiveness.
Solution Approach 2:
The spool valve is designed to be dynamic in its configuration, allowing it to travel toward different sides (first side or second side) depending on the control requirements. This dynamic capability enables the same spool valve structure to adapt to different control scenarios (advance or retard), achieving versatility without requiring multiple fixed structures.
2Reliability
If the retard port and advance port are arranged in different positions, then switching timings can be optimized for specific control directions, but component commonality becomes impossible increasing cost
Solution Approach 1:
The spool valve's ability to travel dynamically toward different sides allows the same physical structure to achieve different switching timings. When the spool valve travels toward the first side, it achieves one switching timing; when it travels toward the second side, it achieves another switching timing. This dynamic positioning enables component commonality while maintaining optimized switching timings for different control directions.
Solution Approach 2:
The spool valve structure incorporates asymmetric oil passage configurations (first spool oil passage and second spool oil passage positioned differently) that allow the same component to function asymmetrically for different control directions, enabling both component commonality and direction-specific optimization.
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 design enhances control responsiveness and achieves cost reduction by allowing common components to be used for both valve timing control devices with different switching timings, improving operational efficiency and reducing production costs.
Implementation Method 1
as the spool valve has traveled toward the second side in the longitudinal direction against a biasing force of a biasing member
Implementation Method 2
a valve timing control device structured to vary a relative rotational phase of a camshaft with respect to a crankshaft by supply and drainage of working oil to and from a first hydraulic chamber and a second hydraulic chamber
Data Source
AI summary
In a first state: a spool valve of a control valve is disposed such that a second spool oil passage is closer to a second side in a longitudinal direction than a first spool oil passage; and as the spool valve has traveled toward the second side against a biasing force of a biasing member, a first port communicates with a second port via the first spool oil passage, a first sleeve oil passage, and the second spool oil passage. In a second state: the spool valve is disposed such that the first spool oil passage is closer to the second side than the second spool oil passage; and as the spool valve has traveled toward a first side in the longitudinal direction, the first port communicates with the second port via the first spool oil passage, the first sleeve oil passage, and the second spool oil passage.