Variable Valve Duration Control via Eccentric Slider Mechanism
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Solution Overview
Problem
Existing continuous variable valve lift (CVVL) and variable valve timing (CVVT) systems are complex and costly, failing to efficiently vary valve opening duration based on engine operation conditions.
Innovation Solution
A continuous variable valve duration system with a camshaft, rocker shaft, and slider housing mechanism, including an eccentric shaft and control gear, allows for variable phase angle adjustment of the camshaft, enabling adaptive valve opening duration through a simple and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If general CVVL and CVVT apparatus are used to achieve optimal valve operation depending on engine speed, then valve timing can be adjusted, but the construction becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent combines the valve timing adjustment function with the existing camshaft rotation mechanism. The inner bracket is integrated into the camshaft assembly, and the slider housing is positioned within the existing valve train structure. This merging of functions allows valve duration control without adding separate complex CVVL or CVVT apparatus, thereby reducing overall construction complexity while maintaining adaptability.
Solution Approach 2:
The camshaft assembly is designed to serve multiple functions: it rotates the cam portions for valve operation, simultaneously controls the phase angle of the inner bracket through the slider housing mechanism, and adjusts valve duration. This multi-functionality eliminates the need for separate dedicated adjustment mechanisms, simplifying the overall construction while achieving optimal valve operation across different engine speeds.
2Adaptability or versatility
If general CVVL and CVVT apparatus are used to achieve optimal valve operation depending on engine speed, then valve timing can be adjusted, but manufacturing cost increases
Solution Approach 1:
By integrating the valve duration control mechanism into the existing camshaft assembly and valve train components, the patent eliminates the need for separate CVVL or CVVT apparatus. This merging reduces the total number of parts that need to be manufactured, assembled, and quality-checked, thereby lowering manufacturing costs while maintaining the capability to adjust valve timing based on engine speed.
Solution Approach 2:
The patent segments the camshaft assembly into functional modules: the cam portions for valve actuation, the inner bracket for phase angle control, and the slider housing for position adjustment. This segmentation allows each component to be manufactured independently using standard processes and then assembled into the complete valve train system, simplifying production and reducing overall manufacturing cost compared to monolithic CVVL/CVVT apparatus.
3Adaptability or versatility
If valve duration is varied according to engine operation conditions, then optimal valve operation is achieved, but existing systems require extensive engine modifications
Solution Approach 1:
The valve duration control mechanism is merged with the existing camshaft assembly, utilizing the same rotation axis and integration points. The inner bracket is positioned within the existing camshaft structure, and the slider housing is installed within the current valve train assembly. This merging approach allows valve duration adjustment without requiring extensive modifications to the engine block, cylinder head, or other major components.
Solution Approach 2:
The control mechanism is nested within the existing valve train structure. The inner bracket is nested in the camshaft assembly, the slider housing is nested within the valve train, and the eccentric shaft is positioned within the slider housing. This nested arrangement allows the valve duration control function to be embedded in the existing engine architecture without requiring external modifications or extensive reconfiguration of the engine system.
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 system reduces the size of the valve train, enhances productivity, and lowers production costs by allowing valve duration adjustment based on engine conditions without extensive engine modifications.
Implementation Method 1
an eccentric shaft inserted into the control hole, and a control portion configured to selectively rotate the eccentric shaft for the slider housing to be moved
Implementation Method 2
a camshaft, a first cam portion including a first cam, into which the camshaft is inserted and of which a relative phase angle of the first cam with respect to the camshaft is variable
Implementation Method 3
a first rocker arm rotatably disposed to the rocker shaft of which a first end contacts with the first cam and a second end is connected to a first valve
Data Source
AI summary
A continuous variable valve duration system may include a camshaft, a first cam portion including a first cam, into which the camshaft is inserted and of which a relative phase angle of the first cam with respect to the camshaft is variable, a rocker shaft disposed parallel to the camshaft, a first rocker arm rotatably disposed to the rocker shaft of which a first end contacts with the first cam and a second end is connected to a first valve, an inner bracket to transmit rotation of the camshaft to the first cam portion, a slider housing into which the inner bracket is rotatably inserted, on which a control hole is formed and on which a guide portion is formed for guiding movement of the slider housing, an eccentric shaft inserted into the control hole, and a control portion to selectively rotate the eccentric shaft.