Camshaft Phaser Integrated Check Valves Torque Actuation
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Solution Overview
Problem
Existing camshaft phasers are parasitic on the lubrication system of internal combustion engines, requiring increased oil pump capacity and adding load to the engine, and their complexity in check valve placement and operation complicates manufacturing and functionality.
Innovation Solution
A camshaft phaser design featuring a valve spool with recirculation check valves that allow oil flow between advance and retard chambers based on torque reversals, reducing the need for external oil pressure and simplifying the structure by integrating check valves within the spool, thereby minimizing parasitic load and manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional camshaft phasers use external oil pressure to control check valves, then reliable oil flow control is achieved, but parasitic load on the engine increases and manufacturing complexity increases
Solution Approach 1:
The check valves are integrated directly into the valve spool structure, merging the valve body and check valve components into a single integrated unit. This eliminates separate check valve assemblies and reduces the number of parts, thereby reducing manufacturing complexity while maintaining reliable oil flow control through the spool's internal passages
Solution Approach 2:
The camshaft torque itself is used to drive the valve spool, eliminating the need for external oil pressure to actuate the phaser. The system uses its own operational torque to control oil flow direction, reducing parasitic load on the engine while maintaining reliable flow control through the integrated check valves
2Loss of energy
If camshaft phasers are actuated by torque reversals, then parasitic load on the engine is reduced, but control precision and reliability may be compromised
Solution Approach 1:
The valve spool is designed to dynamically respond to camshaft torque reversals, automatically shifting position based on the direction of torque. This dynamic actuation method uses the natural torque fluctuations during engine operation to control oil flow, eliminating the need for continuous external actuation while maintaining reliable control through the integrated check valves that lock in the desired position
3Ease of manufacture
If check valves are located remotely from the valve spool, then manufacturing is simplified, but passage complexity and device complexity increase
Solution Approach 1:
The check valves are merged with the valve spool into a single integrated component, eliminating the need for remote placement and complex external passages. The integrated design allows oil flow control to be achieved through internal spool passages, simplifying the overall device structure while maintaining manufacturing feasibility
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 reduces the parasitic load on the engine by utilizing torque reversals to control oil flow, simplifies the manufacturing process, and enhances the operational efficiency of the camshaft phaser by eliminating the need for additional oil pressure to manage check valves, resulting in improved engine performance and reduced complexity.
Implementation Method 1
uses torque reversals of the camshaft to actuate the camshaft phaser
Implementation Method 2
a first recirculation check valve allows oil to pass from the advance chamber to the retard chamber through the spool recirculation passage
Data Source
AI summary
A camshaft phaser includes an input member an output member defining an advance chamber and a retard chamber; a valve spool having a valve spool bore; a first recirculation check valve and a second recirculation check valve disposed within the valve spool bore; and a biasing member which biases the first recirculation check valve and the second recirculation check valve away from each other. The first recirculation check valve allows oil to pass from the advance chamber to the retard chamber and prevents oil from passing from the retard chamber to the advance chamber when the valve spool is in a retard position. The second recirculation check valve allows oil to pass from the retard chamber to the advance chamber and prevents oil from passing from the advance chamber to the retard chamber when the valve spool is in an advance position.