Variable Valve Duration Cam Mechanism for Engine Efficiency
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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 adjust valve opening duration based on engine operation conditions.
Innovation Solution
A continuous variable valve duration apparatus with a camshaft and a roller guide portion that allows variable phase angle adjustment between camshaft and cam slots, utilizing a roller ring and control mechanism to change the relative rotation center, enabling simple and cost-effective adjustment of valve opening duration.
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 system separates valve timing control (camshaft) from valve duration control (cam portion phase angle), allowing independent optimization of each function. The cam portion can rotate independently on the camshaft, enabling duration adjustment without affecting timing control
Solution Approach 2:
The cam portion serves multiple functions: it provides the cam profile for valve actuation, enables variable duration through phase angle adjustment, and maintains fixed timing through its connection to the camshaft. This multi-functionality reduces the need for separate mechanisms
2Adaptability 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 manufacturing cost increases
Solution Approach 1:
The cam portion is integrated with the camshaft through a simplified connection mechanism, combining timing and duration control into a single assembly. This reduces the number of separate components and assembly steps compared to conventional CVVL/CVVT systems
Solution Approach 2:
The cam portion is designed to rotate dynamically on the camshaft, allowing continuous adjustment of phase angle and thus valve duration. This dynamic capability is achieved through a simple rotational mechanism rather than complex actuation 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 reduces the size and complexity of the valve train, enhances productivity, and lowers production costs while optimizing valve operation based on engine conditions, improving fuel efficiency and performance across various load and speed scenarios.
Implementation Method 1
a roller ring which is rotatably disposed to the roller guide portion and is connected to the camshaft slot and the cam slot
Implementation Method 2
a control pin is eccentrically formed from a center of the control shaft and is inserted into the control slot
Data Source
AI summary
A continuous variable valve duration apparatus may vary an opening duration of a valve. The continuous variable valve duration apparatus may include a camshaft in which a camshaft slot is formed, a cam portion of which a cam and a cam slot are formed thereto and of which a rotation center is identical to a rotation center of the camshaft and the cam portion of which a phase angle to the cam shaft is variable, and a duration control portion which varies the phase angle between the camshaft slot and the cam slot.