Camshaft Phaser with Independent Lock Pin and Phase Control
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Solution Overview
Problem
Existing camshaft phasers require three separate oil supply passages in the camshaft bearing, leading to increased length and packaging challenges, and using a single oil control valve coaxially within the phaser for both phase relationship and lock pin control results in increased thickness and loss of independent control.
Innovation Solution
A camshaft phaser design with a phase relationship control valve coaxially within the rotor and a separate lock pin oil control valve outside the phaser, allowing independent control of oil flow to advance and retard chambers and the lock pin, eliminating the need for three separate passages in the camshaft bearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If three separate oil control valves are packaged in the camshaft bearing to control advance chambers, retard chambers, and lock pin independently, then independent control of each function is achieved, but the camshaft bearing length increases significantly
Solution Approach 1:
The patent combines the control of multiple oil passages through a single integrated oil control valve located in the camshaft bearing. The valve uses a single supply signal to control oil flow to advance chambers, retard chambers, and lock pin through internal passage routing, eliminating the need for three separate valves and reducing camshaft bearing length while maintaining independent functional control.
Solution Approach 2:
The patent resolves the spatial conflict by routing oil passages in the radial dimension rather than requiring axial arrangement. The integrated valve uses radial oil passages to distribute oil to different chambers, allowing independent control without increasing the axial length of the camshaft bearing.
2Volume of stationary object
If a single oil control valve is placed coaxially within the camshaft phaser to control both phase relationship and lock pin, then packaging space is reduced, but the camshaft phaser thickness increases and independent control is lost
Solution Approach 1:
The patent segments the control functions by placing the oil control valve in the camshaft bearing rather than within the camshaft phaser. This external placement allows the phaser to remain axially compact while the valve handles multiple control functions through internally routed passages, separating the valving function from the phasing mechanism.
Solution Approach 2:
The camshaft bearing acts as an intermediary housing for the oil control valve and oil passages. The valve in the bearing supplies oil to the phaser components through the camshaft, mediating between the single supply signal and the multiple oil distribution points without requiring the valve to be physically located within the phaser assembly.
3Device complexity
If a single oil control valve is used to control both phase relationship and lock pin, then the number of valves is reduced, but precise independent control of oil flow to each component is difficult to achieve
Solution Approach 1:
The patent uses a dynamic spool valve mechanism with a spool that can be positioned in different states (landed on advance chamber orifice, retarded from retard chamber orifice, etc.) to dynamically control oil flow distribution. The spool's axial position dynamically switches oil pathways, enabling independent control of advance chambers, retard chambers, and lock pin through a single valve actuated by one supply signal.
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 design achieves a compact camshaft phaser with independent control of phase relationship and lock pin functions, reducing the camshaft bearing length and improving packaging efficiency while maintaining precise control over oil flow.
Implementation Method 1
Engine oil is selectively supplied to one of the advance and retard chambers and vacated from the other of the advance and retard chambers in order to rotate the rotor within the stator
Implementation Method 2
The intermediate lock pin is engaged and disengaged by venting oil from the intermediate lock pin and supplying pressurized oil to the intermediate lock pin respectively
Data Source
AI summary
A camshaft phaser is provided for varying the phase relationship between a crankshaft and a camshaft in an engine. The camshaft phaser includes a stator having lobes. A rotor disposed within the stator includes vanes interspersed with the stator lobes to define alternating advance and retard chambers. A lock pin is provided for selective engagement with a lock pin seat for preventing relative rotation between the rotor and stator. Pressurized oil disengages the lock pin from the seat while oil is vented for engaging the lock pin with the seat. A phase relationship control valve is located coaxially within the rotor to control the flow of oil into and out of the chambers. A lock pin oil passage communicates oil to and from the lock pin based on input from a lock pin control valve located outside of the camshaft phaser. The control valves are operational independent of each other.