Camshaft Phaser Control Screw With Multi-Ring Valve Flow Paths
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Solution Overview
Problem
Existing camshaft phaser control valves face challenges in achieving a suitable permeability/size ratio, making it difficult to balance the size of the camshaft phaser with its rotational speed, leading to inefficiencies in hydraulic power consumption and potential disruption of the engine oil circuit.
Innovation Solution
A control screw with a tubular slide valve assembly comprising three rigid rings, flexible arms, and blades, connected to a screw body with an indexing element, is designed to control fluid flow between advance and retard chambers, optimizing the permeability/size ratio and reducing hydraulic power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a ball or spring type valve is used in the control screw, then the valve can control fluid flow between chambers, but the permeability/size ratio is difficult to optimize, making it hard to balance camshaft phaser size with rotational speed
Solution Approach 1:
The valve is segmented into multiple rigid rings (at least three) with flexible arms and blades distributed between them. This segmentation allows the valve to achieve high permeability through multiple flow paths while maintaining compact size, resolving the contradiction between permeability/size ratio and structural complexity.
Solution Approach 2:
The valve incorporates flexible arms that can deform to control fluid flow. These flexible elements provide adaptive flow control with high permeability in a compact structure, eliminating the need for complex ball or spring mechanisms while achieving the desired permeability/size ratio.
2Volume of moving object
If the camshaft phaser size is reduced, then the engine design becomes more compact, but the rotational speed performance deteriorates due to insufficient permeability
Solution Approach 1:
The multi-ring segmented structure creates multiple parallel fluid flow paths, effectively increasing the total permeability area within a compact volume. This allows the camshaft phaser to maintain high rotational speed performance while keeping the overall size reduced.
Solution Approach 2:
The valve structure transitions from a traditional single-plane design to a three-dimensional multi-ring configuration with flexible arms extending between rings. This dimensional change maximizes the permeability surface area within the limited radial and axial space, enabling high rotational speed in a compact phaser.
3Ease of manufacture
If a traditional valve design is used, then the structure is simple to manufacture, but the hydraulic power consumption increases and the engine oil circuit may be disrupted
Solution Approach 1:
The flexible arms in the valve structure automatically deform in response to pressure differential to control fluid flow, eliminating the need for external springs or complex actuation mechanisms. This self-regulating behavior reduces hydraulic power consumption while maintaining manufacturing simplicity through the use of elastic materials.
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 control screw effectively manages fluid flow to enhance rotational speed and reduce hydraulic power consumption, maintaining the integrity of the engine oil circuit while allowing for efficient camshaft phaser operation.
Implementation Method 1
Each valve comprises at least one blade connected to two flexible arms
Implementation Method 2
when the pressure in the advance chamber is higher than the pressure in the retard chamber, the rotor turns in the advance direction
Data Source
AI summary
A control screw for a camshaft phase shifter of an internal combustion engine extends along a longitudinal axis. The control screw includes a screw body. The control screw also includes a tubular spool assembly having a control valve assembly with at least three rigid rings and at least two valves. Each valve includes at least one vane connected to two flexible arms. The valve is connected to two consecutive rigid rings.