Spool Valve Axial Rotation Twin Phaser Control
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Solution Overview
Problem
Hydraulically controlled twin phasers in internal combustion engines face challenges in packaging and leakage due to the need for multiple oil feeds, which complicates the connection of control lines and increases costs, especially in overhead camshaft applications.
Innovation Solution
A spool valve design with two degrees of freedom (axial translation and rotation) that allows independent control of the phase of two driven members, reducing the number of oil feeds required by integrating the spool valve into the cam phaser and using actuators to control its position and orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If four separate oil feeds are used for twin phaser, then independent control of two outputs is achieved, but device complexity and packaging difficulty increase
Solution Approach 1:
The patent merges the control of two outputs into a single integrated spool valve assembly. The spool valve has two degrees of freedom (axial position and rotation) that collectively control four oil feeds, reducing the number of separate sealed interfaces from four to one. This combining approach maintains independent control capability while simplifying the overall system architecture.
Solution Approach 2:
The spool valve introduces a rotational degree of freedom in addition to axial movement, adding a dimensional aspect to the control mechanism. By rotating the spool valve around its axis, the system can selectively connect different oil feeds without requiring separate linear actuators for each connection, thereby reducing complexity while maintaining full control capability.
2Ease of manufacture
If oil feeds pass through camshaft via grooves and passageways, then connection is simplified, but bearing surface area is reduced and leakage risk increases
Solution Approach 1:
The patent extracts the oil feed control function from the camshaft bearing structure by using a separate, dedicated spool valve assembly. This separation allows the camshaft bearings to maintain their full surface area without grooves or passageways that would compromise their load-bearing capacity or create leakage paths. The oil feeds are managed in a dedicated hydraulic control section rather than through the mechanical bearing surfaces.
3Volume of moving object
If spool valve is integrated into cam phaser, then packaging space is improved, but control mechanism complexity increases
Solution Approach 1:
The spool valve assembly is designed to perform multiple functions within a single integrated structure. It simultaneously controls four oil feeds through two degrees of freedom (axial and rotational movement), providing a universal control mechanism that replaces what would otherwise require four separate control elements. This multi-functionality reduces the overall volume required while maintaining full control capability.
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 simplifies the hydraulic control system by reducing the number of oil feeds, minimizing leakage, and improving packaging efficiency, while maintaining independent control of the phase of each output member, thus enhancing the operational reliability and cost-effectiveness of the twin phaser.
Implementation Method 1
a spool valve for controlling a twin phaser... axial displacement of the spool relative to the bore serves to control a phase of a first output member
Implementation Method 2
rotation of the spool relative to the bore serves to control a phase of a second output member
Data Source
AI summary
A spool valve for controlling a twin phaser for coupling a drive member to two driven members and to enable the phase of the two driven members to be varied independently includes a bore operably associated with the twin phaser, fluid channels opening into the bore, and a spool. The spool is received in and is moveable relative to the bore so as to selectively open and close the fluid channels in a predetermined manner, thereby providing a fluid communication between the spool and the twin phaser, and varying a phase of output members relative to an input member. The spool and the fluid channels are configured so that an axial displacement of the spool relative to the bore serves to control a phase of a first output member, and a rotation of the spool relative to the bore serves to control a phase of a second output member.