Continuous Variable Valve Duration Cam 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 apparatus with a camshaft, variable phase angle cam portions, inner brackets, slider housings, and a control mechanism using an eccentric control shaft and motor to adjust the relative positions of the slider housings, allowing for variable valve opening duration without excessive modification to the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If general CVVL and CVVT systems are used to achieve optimal valve operation depending on engine speed, then valve timing and lift can be adjusted, but the construction becomes complicated and manufacturing cost increases
Solution Approach 1:
The camshaft is divided into multiple cam portions (first cam portion, second cam portion, third cam portion, fourth cam portion) that can be independently rotated relative to each other. Each cam portion can be adjusted to different phase angles independently, allowing separate control of valve timing and duration without requiring complex integrated systems. The inner brackets are also segmented to transmit rotation to specific cam portions independently.
Solution Approach 2:
The system enables dynamic adjustment of cam portion phase angles during engine operation through the slider mechanism. The slider housing can be selectively positioned to different locations, allowing the cam portions to be rotated to optimal phase angles based on real-time engine operating conditions, making the valve train dynamically adaptable rather than fixed.
2Adaptability or versatility
If existing CVVL and CVVT systems are implemented, then valve timing control is achieved, but the system size and complexity increase without efficient valve duration variation
Solution Approach 1:
The camshaft assembly serves multiple functions simultaneously: it provides valve timing control through phase angle adjustment, valve duration control through relative cam portion rotation, and maintains compact integration within the engine head. The slider mechanism serves both as a positioning mechanism for the cam portions and as a space-efficient transmission element, eliminating the need for separate bulky adjustment mechanisms.
3Reliability
If traditional valve timing systems are used, then fixed valve timing is achieved, but the system cannot efficiently adapt to varying engine operation conditions
Solution Approach 1:
The system incorporates sensors that detect engine operating conditions (such as engine speed, load, and temperature) and feed this information to the control unit. The control unit processes this feedback and selectively positions the slider housing to appropriate locations, which in turn rotates the cam portions to optimal phase angles that match the current engine conditions, ensuring reliable valve operation across all operating ranges.
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 solution reduces the size and complexity of the valve train, enhances productivity, and lowers production costs by allowing the valve duration to be adjusted according to engine conditions with a simple construction, while maintaining optimal valve operation.
Implementation Method 1
The control portion may include an eccentric control shaft inserted into the control slot and a control motor selectively rotating the eccentric control shaft in order to change the relative position of the sliding housing.
Data Source
AI summary
A continuous variable valve duration apparatus may include a camshaft, a first cam portion and a second cam portion of which a cam is formed thereto respectively, of which the camshaft is inserted thereto, of which relative phase angles with respect to the camshaft are variable, and the first and second cam portions disposed on one cylinder and the next cylinder respectively, a first inner bracket and a second inner bracket transmitting rotation of the camshaft to the first and second cam portions respectively, a slider housing of which the first and second inner brackets are rotatably inserted thereto and of which relative position with respect to the camshaft is variable and a control portion selectively changing the relative position of the slider housing.