Continuous Variable Valve Duration Camshaft Mechanism
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Solution Overview
Problem
Existing continuous variable valve lift (CVVL) and variable valve timing (CVVT) systems are complex and costly, making them inefficient for optimizing valve operation based on engine speed.
Innovation Solution
A continuous variable valve duration apparatus with a camshaft, variable phase angle cam portions, inner brackets, slider housing, control shaft, and a control portion that adjusts valve opening duration based on engine operation conditions, featuring a simplified design that reduces size and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If general CVVT apparatus is used to change valve timing, then valve timing can be adjusted according to engine speed, but the construction becomes complicated and manufacturing cost increases
Solution Approach 1:
The camshaft is divided into first and second cam portions that can rotate independently relative to each other. This segmentation allows the invention to achieve variable valve duration functionality that traditionally required complex CVVT systems, thereby simplifying the overall construction while maintaining adaptability.
Solution Approach 2:
The camshaft structure is designed to perform multiple functions: it simultaneously controls valve timing and valve duration through the independent rotation of first and second cam portions. This multi-functionality eliminates the need for separate CVVT mechanisms, reducing construction complexity while maintaining versatile adjustment capability.
2Reliability
If complex CVVL and CVVT systems are implemented, then optimal valve operation can be achieved, but manufacturing cost increases
Solution Approach 1:
The invention merges the functions of CVVL and CVVT into a single integrated camshaft structure with first and second cam portions. This consolidation maintains optimal valve operation control while significantly reducing manufacturing cost by eliminating the need for separate complex systems.
Solution Approach 2:
The camshaft is designed as a multi-functional component that simultaneously achieves variable valve lift and variable valve timing effects through the differential rotation of its cam portions, thereby maintaining reliability while reducing manufacturing complexity and cost.
3Stability of the object's composition
If traditional valve train design is used, then structural stability is maintained, but the overall height increases and productivity decreases
Solution Approach 1:
The guide head is rotatably inserted into the slider housing, creating a nested structure where the guide head rotates within the confines of the slider housing. This nesting arrangement maintains structural stability while minimizing the overall height of the valve train, thereby improving space utilization and productivity.
4Measurement precision
If more components are added to achieve precise valve control, then valve operation precision improves, but device complexity and production cost increase
Solution Approach 1:
The invention introduces dynamic control through the rotatable guide head that can change the phase angle between first and second cam portions. This dynamic mechanism achieves precise valve duration control without requiring additional static components, thereby maintaining simplicity while improving control precision.
Solution Approach 2:
The phase angle between cam portions is changed as a control parameter to achieve precise valve duration adjustment. By varying this angular parameter through the rotatable guide head, the system achieves precise control with minimal additional components, avoiding increased device complexity.
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 allows for precise adjustment of valve duration according to engine conditions, reducing the overall height of the valve train, enhancing productivity, and lowering production costs while maintaining efficient engine operation.
Implementation Method 1
a control shaft parallel to the camshaft and on which a control rod is eccentrically formed
Data Source
AI summary
A continuous variable valve duration apparatus may include: a camshaft; first and second cam portions on which a cam is formed respectively, the camshaft being inserted into the first and second cam portions such that relative phase angles with respect to the camshaft are variable; first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively; a slider housing in which the first and the second inner brackets are rotatably inserted; first and second guiding portions formed on the slider housing; a cam cap on which a cam cap guide contacting the second guiding portion is formed; a control shaft parallel to the camshaft; a control rod eccentrically formed on the control shaft; a guide head on which a head guiding portion and a head hole are formed; and a control portion selectively rotating the control shaft.