Continuous Variable Valve Duration Apparatus for Engine Optimization
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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 simplified design, featuring a camshaft, variable phase cam portions, inner brackets, a cam lifter, and a control portion with a screw shaft and planetary gear set, allowing for adjustable valve opening duration based on engine conditions without excessive modification to existing engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If general CVVL or CVVT systems are used to achieve optimal valve operation depending on engine speed, then valve timing and lift can be adjusted, but device complexity and manufacturing cost increase
Solution Approach 1:
The camshaft is divided into first and second cam portions with independently adjustable relative phase angles, allowing separate optimization of intake and exhaust valve timing without requiring complex integrated systems. This segmentation enables targeted adjustment of valve operations while maintaining overall system simplicity.
Solution Approach 2:
The control portion serves multiple functions: it adjusts the relative phase angles between cam portions, controls valve duration, and integrates with the camshaft rotation. This multi-functionality reduces the need for separate adjustment mechanisms, thereby simplifying the overall device construction while maintaining adaptability.
2Adaptability or versatility
If general CVVL or CVVT systems are used to achieve optimal valve operation depending on engine speed, then valve timing and lift can be adjusted, but manufacturing cost increases
Solution Approach 1:
The first and second cam portions are nested within the same camshaft structure, with the control portion integrated into the camshaft assembly. This nesting reduces the number of separate components and assembly steps, thereby lowering manufacturing costs while maintaining the ability to adjust valve operations.
Solution Approach 2:
The control portion combines multiple adjustment functions (phase angle control, duration control) into a single integrated mechanism that operates with the camshaft. This merging of functions reduces the total component count and simplifies manufacturing processes, leading to lower production costs.
3Adaptability or versatility
If variable valve duration is implemented to optimize engine performance, then valve opening duration can be adjusted according to operation conditions, but valve train complexity increases
Solution Approach 1:
The system dynamically adjusts the relative phase angles between cam portions and the cam lifter guide position based on engine operating conditions. This dynamic adjustment enables continuous variable valve duration control without requiring multiple fixed-duration cam profiles, thereby simplifying the valve train structure.
Solution Approach 2:
The cam lifter guide acts as an intermediary element that translates rotational motion of the camshaft into controlled linear motion of the cam lifter, enabling duration control through positional adjustment rather than complex mechanical linkages. This intermediary mechanism simplifies the overall valve train structure.
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 reduces the size and complexity of the valve train, enhances productivity, and lowers production costs while enabling optimal valve operation based on engine speed, reducing power loss and simplifying engine layout.
Implementation Method 1
a planetary gear set connected to the screw shaft and transmitting rotation of the control motor to the screw shaft
Implementation Method 2
The control portion may further include a worm wheel connected to the planetary gear set and a worm gear engaged with the worm wheel
Implementation Method 3
a screw shaft parallel to the camshaft; and an adapter engaged with the screw shaft, on which an adapter guide slidably engaged with the cam lifter guide and moving a relative position of the cam lifter according to rotation of the screw shaft
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 inserted to the first and second cam portions of which 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 cam lifter in which the first and second inner brackets are rotatably inserted, and a cam lifter guide slantly formed on the cam lifter; a cam cap rotatably supporting the first and the second cam portions, and the cam lifter slidably mounted to the cam cap; a control portion including a screw shaft parallel to the camshaft; and an adapter engaged with the screw shaft, on which an adapter guide slidably engaged with the cam lifter guide and moving a relative position of the cam lifter.