Variable Valve Control Device Using Hydraulic Phase Shifting
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Solution Overview
Problem
Existing variable valve timing systems for reciprocating engines face challenges in efficiently adjusting valve opening duration and lift without energy loss, particularly due to the complexity and high cost of mechanical devices and the energy loss in electro-hydraulic systems, as well as limitations in minimizing valve lift threshold and energy retention.
Innovation Solution
A control device utilizing a simple rotary phase shifter connecting two synchronous camshafts, with a body containing non-deformable cavities and pistons that maintain a constant hydraulic fluid volume, allowing for adjustable angular duration and lift of valve opening by modifying the phase shift angle between camshafts, ensuring energy retention and precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanical devices are used to vary valve duration and lift, then valve timing control is achieved, but device complexity and manufacturing cost increase due to great machining precision requirements
Solution Approach 1:
The patent replaces complex mechanical deformation systems with a simpler hydraulic system. Instead of mechanically deforming a single cam profile, the invention uses hydraulic pressure transmitted through incompressible fluid to control valve timing and lift, significantly reducing mechanical complexity and machining precision requirements
Solution Approach 2:
The invention extracts the timing control function from the cam profile itself and separates it into an independent hydraulic control system. The cam profiles remain simple and fixed, while valve timing is controlled by hydraulic actuation, removing the complexity of variable cam geometry
2Adaptability or versatility
If electro-hydraulic devices are used to control valve timing, then valve timing adjustment is achieved, but energy is lost due to lamination of hydraulic fluid and dependence on lubricating oil viscosity
Solution Approach 1:
The patent maintains continuous hydraulic pressure throughout the system using incompressible fluid, eliminating energy loss from fluid lamination. The hydraulic system operates continuously without the intermittent energy losses associated with electro-hydraulic actuation and lubricating oil viscosity changes
Solution Approach 2:
The invention changes the physical parameters of the hydraulic system by using incompressible fluid instead of compressible lubricating oil. This parameter change eliminates energy loss due to fluid compression and viscosity variations, maintaining energy efficiency during valve timing adjustment
3Adaptability or versatility
If a single cam profile is deformed to generate valve movement, then valve timing control is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The invention segments the valve control system into separate functional components: fixed cam profiles for basic timing, and independent hydraulic actuators for precise timing adjustment. This segmentation allows each component to be manufactured with standard precision while achieving sophisticated variable valve timing control
Solution Approach 2:
The patent substitutes mechanical cam profile deformation with hydraulic actuation. Instead of manufacturing complex variable geometry cams, the system uses simple fixed cams combined with hydraulic pressure control, dramatically reducing manufacturing precision requirements
4Adaptability or versatility
If hydraulic fluid is used to mix cam profiles, then valve opening duration is modulated, but minimum valve lift threshold prevents complete closure
Solution Approach 1:
The invention extracts the hydraulic control function from the cam profile mixing approach and implements it as a separate actuation system. This allows the hydraulic system to control valve timing without interfering with the mechanical closure function, enabling complete valve closure when needed
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
Enables continuous adjustment of valve opening duration and lift without energy loss, maintaining energy accumulated in return means, and allows for precise control of valve operation, including total closure and synchronization of twin valves, while simplifying the mechanical design and reducing costs.
Implementation Method 1
The portion of the cavity delimited by the pistons is filled with a constant reference volume of substantially incompressible hydraulic fluid
Implementation Method 2
the elastic return means of the shuttle piston and of the valve are such that the pressure of the fluid required to move the shuttle piston to its bottom dead center is less than the pressure required to open the valve
Data Source
Figure 1
Figure 2A~2C
Figure 2D~2E
AI summary
The invention relates to a device for controlling at least one valve (2), comprising a body (8) comprising a dimensionally stable cavity (9) communicating exclusively with the outside by means of at least four straight cylinders (10, 11, 12, 13) closed respectively by an opening piston (P1) actuated by an opening cam (C1), a closing piston (P2) actuated by a closing cam (C2), a shuttle piston (Pa) for arming or disarming the device, and a piston (Ps) mechanically linked to the valve (2). The control device according to the invention is used to adjust, during operation and by adjusting the angular phase difference between the opening cam (C1) and the closing cam (C2), the valve lift (2), the angular duration of opening of the valve (2) and, if necessary, to completely deactivate the valve (2) for the entire duration of a cycle.