Variable Cam Timing Phaser With Remote Solenoid Actuator
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Solution Overview
Problem
Existing cam timing phaser arrangements in commercial vehicles face issues with mechanical complexity, sensitivity to impurities, oil leakage, and durability, particularly due to the use of three-positional spool valves and compact, complex rotor designs with specialized check valves, leading to increased costs and reduced robustness.
Innovation Solution
A variable cam timing phaser arrangement utilizing a rotor with vanes and a stator, featuring a centrally-mounted on/off piloted valve and a remotely-located solenoid-controlled actuator, which simplifies the system by reducing the need for precise solenoid regulation and minimizing oil leakage paths, allowing for more robust and cost-effective construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a three-positional spool valve is used to control oil flow in the cam timing phaser, then the valve timing can be adjusted, but the system becomes mechanically complex and sensitive to impurities
Solution Approach 1:
The patent extracts the solenoid actuator from the rotating cam phaser assembly and places it on the engine block. This separates the control function from the rotating components, eliminating the need for a complex three-positional spool valve that must operate in a rotating environment. The solenoid directly controls a simple two-position valve, dramatically reducing mechanical complexity while maintaining valve timing adjustment capability.
Solution Approach 2:
The patent introduces an intermediary valve mechanism that translates the solenoid's linear motion into rotational movement of the cam phaser. Instead of using a complex multi-positional valve, a simple two-position valve controls oil flow to advance or retard the camshaft timing, reducing sensitivity to impurities and mechanical complexity.
2Volume of moving object
If a centrally-mounted oil control valve is used in the rotating cam phaser, then the system is compact, but the solenoid contact with the valve causes wear and reduced position accuracy
Solution Approach 1:
The solenoid actuator is extracted from the rotating cam phaser assembly and mounted on the stationary engine block. This eliminates the sliding contact between the solenoid pin and the oil control valve that occurs in centrally-mounted designs. The valve remains simple and two-position, maintaining reliability while the system remains compact through optimized oil channel design.
3Volume of moving object
If a compact rotor design with specialized check valves is used, then the phaser fits within limited space, but the system becomes more sensitive to impurities and less robust
Solution Approach 1:
The patent replaces specialized, complex check valves with simpler valve mechanisms that are less sensitive to impurities. The two-position valve design uses standard, robust components that can tolerate the presence of contaminants better than specialized check valves, improving overall system robustness while maintaining compact dimensions through optimized oil channel geometry.
4Measurement precision
If precise solenoid regulation is used to control the oil control valve, then the valve timing control is accurate, but the system cost increases
Solution Approach 1:
The solenoid is extracted from the rotating assembly and mounted on the engine block, where it can use a simple two-position design rather than requiring precise multi-position regulation. The valve timing accuracy is achieved through the precise timing of solenoid activation relative to camshaft rotation, not through complex solenoid positioning, thereby reducing system cost while maintaining control accuracy.
Solution Approach 2:
The solenoid is activated periodically at specific points in the camshaft rotation cycle to achieve precise valve timing control. By synchronizing the solenoid activation with the camshaft position, the system achieves accurate timing control using a simple two-position valve rather than requiring expensive precise regulation mechanisms.
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 results in a more robust, less complex, and less prone to oil leakage cam phaser system, with reduced risk of valve jamming and improved durability, enabling better engine performance and fuel efficiency in commercial vehicles.
Implementation Method 1
a solenoid-controlled actuator... in fluid communication with the pilot port... arranged to switch the piloted valve... by regulating the pressure of the pilot fluid at the pilot port
Implementation Method 2
the piloted valve is switchable between an open state and a closed state by regulation of the pressure of a pilot fluid at the pilot port
Implementation Method 3
the introduction of hydraulic fluid into the first chamber causes the rotor to move in a first rotational direction relative to the stator and the introduction of hydraulic fluid into the second chamber causes the rotor to move in a second rotational direction relative to the stator
Data Source
AI summary
A variable cam timing phaser arrangement is disclosed, comprising: a rotor having at least one vane; a stator co-axially surrounding the rotor, having at least one recess for receiving the at least one vane of the rotor, wherein the at least one vane divides the at least one recess into an first chamber and a second chamber; and a control assembly for regulating hydraulic fluid flow from the first chamber to the second chamber or vice-versa. The control assembly comprises a central on/off piloted valve for allowing or preventing fluid communication between the first and second chambers, and a remotely located solenoid-controlled actuator for controlling the on/off piloted valve. The present disclosure further relates to a method of controlling the timing of a camshaft in an internal combustion engine. The disclosure also relates to an internal combustion engine and a vehicle comprising the disclosed variable cam timing phaser arrangement.