Continuous Variable Valve Duration Apparatus Design
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Solution Overview
Problem
Existing continuous variable valve systems for internal combustion engines, such as CVVL and CVVT, are complex and costly due to their construction, which complicates optimal valve operation based on engine speed.
Innovation Solution
A continuous variable valve duration apparatus with a camshaft, cam device, internal bracket, wheel housing, control shaft, and slider housing, allowing for variable valve opening duration through a simple construction that includes a guide groove, control shaft, and slider housing with a 'U' cross-section, reducing size and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If general CVVL or CVVT systems are used to achieve optimal valve operation, then valve timing and lift can be adjusted according to engine speed, but the construction becomes complicated and manufacturing cost increases
Solution Approach 1:
The cam device is divided into a cam portion and a cam follower portion that can move relative to each other along the camshaft axis. This segmentation allows independent adjustment of valve duration while maintaining a relatively simple overall structure, resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The cam follower is nested within the cam device structure, with the cam follower portion moving along the camshaft axis within the cam device housing. This nesting approach compactly integrates multiple functions into a single apparatus, reducing construction complexity while maintaining adaptability.
2Adaptability or versatility
If existing valve duration control mechanisms are implemented, then valve opening duration can be varied, but the apparatus size and manufacturing cost increase
Solution Approach 1:
The cam device integrates the cam portion, cam follower portion, and duration control function into a single compact unit. The cam follower moves along the camshaft axis within the cam device housing, combining multiple functions in one apparatus, thereby reducing overall size while maintaining valve duration variability.
3Reliability
If conventional valve timing systems are used, then optimal valve operation can be achieved, but friction and vibration increase
Solution Approach 1:
The cam follower is designed to move dynamically along the camshaft axis while maintaining continuous contact with the cam portion. This dynamic adjustment allows optimal valve operation across different engine speeds while reducing impact and vibration compared to fixed timing systems.
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 apparatus enables optimal valve operation based on engine conditions with reduced size and production costs, enhancing productivity by applying to conventional engines with minimal modifications, while minimizing noise, vibration, and friction.
Implementation Method 1
the slider housing interposed between the control shaft and the guide groove
Data Source
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AI summary
A continuous variable valve duration apparatus may include a camshaft, a cam device on which a cam is formed, of which the camshaft is inserted thereto and of which a relative phase angle with respect to the camshaft is variable, an internal bracket transmitting rotation of the camshaft to the cam device, a wheel housing in which the internal bracket is rotatably inserted and on which a guide groove parallel to the camshaft is formed, a control portion including a control shaft disposed parallel to the camshaft and inserted into the guide groove, and the control portion selectively rotating the control shaft for the relative position of the wheel housing with respect to the camshaft to be changed and a slider housing interposed between the control shaft and the guide groove.