Camshaft Phaser Check Valve Assembly for Oil Flow Control
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Solution Overview
Problem
Existing vane-type camshaft phasers have a filter and check valve arrangement within the camshaft phaser attachment bolt that is compact but renders the filter unserviceable and susceptible to plugging when operational issues arise, limiting its effectiveness in maintaining oil flow and phase relationship between the crankshaft and camshaft.
Innovation Solution
A camshaft phaser with a check valve assembly and filter located in the camshaft phaser attachment bolt, featuring a stepped bore and a check valve body with guiding walls and clearance walls to prevent backflow, allowing for easy maintenance and reducing the risk of plugging by providing a larger filtering area and external accessibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the filter is located within the camshaft phaser attachment bolt, then the device is compact, but the filter becomes unserviceable and susceptible to plugging
Solution Approach 1:
The filter is segmented from the main camshaft phaser assembly and placed in a separate, externally accessible location. This allows the filter to be independently serviced without disassembling the camshaft phaser attachment bolt, resolving the contradiction between compactness and serviceability.
Solution Approach 2:
The filter is extracted from the internal bore of the camshaft phaser attachment bolt and repositioned in an external location that is easily accessible for maintenance. This extraction maintains the compact internal structure while enabling independent filter servicing.
2Volume of moving object
If the filter is located within the camshaft phaser attachment bolt, then the device is compact, but the filter area is small making it susceptible to plugging
Solution Approach 1:
The filter is repositioned to utilize external space dimensions rather than being constrained within the internal bore volume. This dimensional relocation allows for a larger filter surface area while maintaining overall device compactness.
Solution Approach 2:
The filter location is optimized for local quality characteristics including increased filtration surface area and improved oil flow distribution across the filter medium, reducing susceptibility to plugging while maintaining compact overall device dimensions.
3Reliability
If a check valve assembly is added to prevent backflow, then oil backflow is prevented, but device complexity increases
Solution Approach 1:
The check valve assembly is merged with the existing camshaft phaser attachment bolt structure, utilizing the same bore and integration points. This combining approach prevents oil backflow while minimizing the increase in overall device complexity by reusing existing structural elements.
Solution Approach 2:
The camshaft phaser attachment bolt is designed to serve multiple functions: mechanical attachment, oil passage conduit, and check valve housing. This multi-functionality reduces device complexity by eliminating the need for separate components while ensuring reliable oil backflow prevention.
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 effectively prevents oil backflow and maintains efficient oil flow by ensuring the filter is easily accessible and less prone to plugging, thereby ensuring reliable operation and phase control between the crankshaft and camshaft.
Implementation Method 1
a spring for biasing the check valve body toward the shoulder
Implementation Method 2
The guiding walls ride closely against the larger diameter bore
Implementation Method 3
When pressure within the camshaft phaser is elevated to a pressure that is higher than the oil source, the ball is seated against a shoulder in the bore to prevent backflow of oil to the oil source
Data Source
AI summary
A camshaft phaser for controllably varying the phase relationship between a crankshaft and a camshaft in an internal combustion engine is attached to the camshaft with a camshaft phaser attachment bolt. The camshaft phaser attachment bolt includes a stepped bore for communicating pressurized oil from the internal combustion engine to a valve spool and is defined by a larger diameter bore, a smaller diameter bore, and a shoulder between the larger diameter bore and the smaller diameter bore. A check valve assembly includes a check valve body axially moveable within the larger diameter bore. The check valve body includes a plurality of azimuthally spaced guiding walls, a plurality of clearance walls separating the guiding walls, and a seating surface at one end of the guiding walls and the clearance walls for selectively seating with the shoulder to prevent fluid communication between the larger diameter bore and the smaller diameter bore.