Rotational Hydraulic Logic Valve for Cam Timing Phaser
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Solution Overview
Problem
Existing cam timing phaser arrangements for 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.
Innovation Solution
A control valve with a cylindrical body and rotational shuttle element that allows directional fluid flow using a blocking pin, reducing mechanical complexity and oil leakage, and allowing for robust, simple actuation with a single on/off solenoid, and external check valves, enhancing durability and manufacturing simplicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three-positional spool valves are used to control oil flow in cam timing phasers, then precise control over camshaft timing is achieved, but mechanical complexity and sensitivity to impurities increase
Solution Approach 1:
The patent extracts the complex three-positional spool valve mechanism and replaces it with a simpler two-positional spool valve combined with a blocking pin system. The blocking pin is selectively positioned to block either the advance chamber or retard chamber, achieving three-positional functionality (advance, hold, retard) through a simpler valve structure that is less sensitive to impurities and easier to manufacture.
Solution Approach 2:
The control function is segmented into two independent components: a two-positional spool valve for basic oil flow control and a blocking pin for directional selection. This segmentation allows each component to be simpler and more robust, while their combination achieves the required three-positional control functionality with reduced mechanical complexity.
2Productivity
If compact rotor designs with specialized check valves are used, then cam timing phasing effectiveness is improved, but durability and manufacturing simplicity deteriorate
Solution Approach 1:
The patent extracts the specialized check valves from the compact rotor design and relocates them to the valve body. This allows the rotor to采用 simpler, more durable structures while the check valves are positioned where they can be more easily manufactured, maintained, and replaced, improving overall system reliability without compromising phasing effectiveness.
Solution Approach 2:
The valve body serves as an intermediary structure that houses the check valves and blocking pin mechanism. This intermediary design allows the rotor to focus on its primary phasing function with simpler geometry, while the valve body provides the complex flow control functions, separating concerns and improving both durability and manufacturability.
3Measurement precision
If three-positional spool valves are used for precise oil distribution, then camshaft timing control is improved, but oil leakage increases
Solution Approach 1:
The patent extracts the oil leakage problem from the three-positional spool valve design and addresses it through a two-positional valve with blocking pin. The blocking pin creates more effective sealing by blocking entire chambers rather than relying on precise spool positioning, reducing oil leakage paths while maintaining timing control precision through the blocking mechanism.
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 provides a more robust, less complex, and less prone to leakage cam timing phaser arrangement, improving durability and reducing oil consumption, while maintaining precise control over camshaft timing, thus enhancing engine performance and reducing emissions.
Implementation Method 1
a rotational shuttle element coaxially located within the recess of the valve body; wherein the recess and rotational shuttle element together define a signalling chamber and a flow chamber; wherein the rotational shuttle element is arranged to rotate between at least three positions in response to fluid pressure variations in the first and second signalling chambers
Implementation Method 2
an actuable blocking pin is configured in the control valve and the rotational shuttle element is configured with two corresponding holes for receiving the blocking pin, a first hole arranged to block the rotational shuttle element from moving to the first position upon receiving the blocking pin and a second hole arranged to block the rotational shuttle element from moving to the second position upon receiving the blocking pin
Implementation Method 3
The exact period, magnitude and shape of the cam torque variation depends on a number of factors including the number of valves regulated by the camshaft and the engine rotation frequency. Positive torque resists cam rotation, while negative cam torque aids cam rotation.
Implementation Method 4
Cam torque actuated phasers utilize these periodic torque variations to rotate the rotor in the chosen direction, thereby advancing or retarding the camshaft timing. In principle they operate as 'hydraulic ratchets', allowing fluid to flow in a single direction from one chamber to the other chamber due to the torque acting on the oil in the chambers and causing periodic pressure fluctuations.
Implementation Method 5
The reverse direction of fluid flow is prevented by check valve. Therefore, the rotor will be rotationally shifted relative to the stator every period the torque acts in the relevant direction, but will remain stationary when the torque periodically acts in the opposite direction.
Data Source
AI summary
A control valve for use in a cam timing phaser arrangement is disclosed comprising a cylindrical valve body, a rotational shuttle element coaxially located within a recess of the valve body, and a blocking pin. When using in a cam timing phaser arrangement having a first phasing chamber and a second phasing chamber, the control valve when non-actuated acts as a double check valve, preventing flow between chambers. Actuation of the blocking pin limits rotation of the rotational shuttle element and results in the control valve allowing flow in a single flow direction between phasing chambers. The allowed direction of flow can be controlled by controlling the timing of the deployment of the blocking pin. A cam timing phaser arrangement, internal combustion engine, and vehicle comprising such a control valve are also disclosed.