Spool Valve Oil Circuit for Variable Valve Lift Mode Switching
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Solution Overview
Problem
Existing variable valve actuation (VVA) technologies for engines, such as 1.5 stroke engine brake and cylinder deactivation systems, require multiple oil control valves for complex valve lift control, leading to inefficiencies and increased complexity.
Innovation Solution
A spool valve assembly and oil control circuit with two oil control valves and a spool valve that allows for automatic control of oil flow, enabling efficient switching between different variable valve lift modes by balancing pressure across oil galleries, reducing the number of required valves and simplifying control logic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple oil control valves are used for complex valve lift control, then the valve control precision is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple oil control valves into a single spool valve assembly that can control multiple oil galleries simultaneously. The spool valve has multiple positions that allow it to direct oil flow to different galleries, replacing the need for separate valves for each gallery while maintaining precise control over valve lift modes.
Solution Approach 2:
The spool valve assembly is designed to perform multiple functions: it can control engine brake mode, cylinder deactivation mode, and all-active mode by directing oil flow to different galleries. This multi-functional design eliminates the need for dedicated valves for each control function, reducing overall device complexity while preserving control precision.
2Adaptability or versatility
If multiple oil control valves are used for complex valve lift control, then the adaptability is improved, but the ease of manufacture worsens
Solution Approach 1:
By merging multiple control functions into a single spool valve assembly, the patent reduces the number of discrete components that need to be manufactured and assembled. The unified design simplifies the manufacturing process while maintaining the ability to switch between multiple valve lift modes through the spool valve's different positions.
3Device complexity
If the number of valves is reduced, then the device complexity is reduced, but the control precision may worsen
Solution Approach 1:
The spool valve assembly is segmented into multiple control sections, each capable of directing oil flow to specific galleries. This segmentation allows the single valve to maintain precise control over multiple oil galleries independently, preventing any loss of control precision despite reducing the total number of valves.
Solution Approach 2:
The spool valve acts as an intermediary mechanism that translates a single control input into multiple controlled outputs by directing oil flow to different galleries. This intermediary function ensures that reducing the number of valves does not compromise control precision, as the spool valve mediates the distribution of oil flow to maintain accurate valve lift control.
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 enables efficient switching between engine brake, cylinder deactivation, and all-active modes, enhancing braking performance and engine efficiency while reducing the number of valves needed, thus simplifying the control system and potentially lowering manufacturing and maintenance costs.
Implementation Method 1
A spool valve assembly and oil control circuit with two oil control valves and a spool valve that allows for automatic control of oil flow, enabling efficient switching between different variable valve lift modes by balancing pressure across oil galleries
Data Source
AI summary
A spool valve assembly operable for an automatic control of an oil flow, the spool valve assembly including an outer case, a spool valve configured to slide axially within the outer case, a first inlet port on the outer case configured for connecting with a first oil gallery, wherein the first oil gallery is operable as an outlet of a first oil control valve, a second inlet port on the outer case configured for connecting with a second oil gallery, wherein the second oil gallery is operable as an outlet of a second oil control valve, a spool outlet on the outer case configured for connecting with a third oil gallery, and a return spring configured to cause the spool valve to return to a rest position.