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 due to their intricate constructions, which hinder optimal valve operation based on engine rotation speed.
Innovation Solution
A continuous variable valve duration apparatus with a camshaft, cam device, internal bracket, wheel housing, guide portion, and control portion, featuring a simple construction that allows for variable valve opening duration adjustment through a control shaft and roller cam mechanism, reducing manufacturing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If general CVVT apparatus is used to change valve timing, then valve timing operation can be adjusted according to engine speed, but the construction becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent applies the dynamics principle by making the cam device rotatable relative to the camshaft through a control portion that adjusts the phase angle between them. This dynamic adjustment mechanism allows continuous variation of valve timing and duration without requiring complex multiple camshafts or lift mechanisms, thereby achieving adaptability while maintaining construction simplicity.
Solution Approach 2:
The patent merges the valve timing adjustment function and valve duration adjustment function into a single integrated mechanism. By combining the cam device rotation control with the phase angle adjustment, the system achieves both timing and duration variability through one unified structure, reducing overall device complexity compared to separate CVVT and CVVL systems.
2Adaptability or versatility
If general CVVL apparatus is used to change valve lift, then valve lift can be adjusted according to engine speed, but the construction becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent applies dynamics by enabling continuous adjustment of the cam device's phase angle relative to the camshaft. This dynamic positioning allows the valve lift to be continuously varied according to engine operating conditions without requiring discrete cam profiles or complex hydraulic/lift mechanisms, achieving adaptability with simplified construction.
3Reliability
If existing CVVT and CVVL systems are implemented, then optimal valve operation can be achieved, but manufacturing cost and production complexity increase
Solution Approach 1:
The dynamic phase angle adjustment mechanism provides reliable optimal valve operation across different engine speeds while maintaining ease of manufacture. The simple rotational adjustment system requires minimal additional components compared to conventional CVVT/CVVL systems, reducing manufacturing complexity and cost while achieving the same performance goal.
Solution Approach 2:
The patent achieves optimal valve operation by continuously changing the phase angle parameter between the camshaft and cam device. This single parameter adjustment allows the system to adapt to varying engine conditions without requiring multiple discrete cam profiles or complex mechanisms, thereby maintaining ease of manufacture while achieving reliable optimal performance.
Data Source
AI summary
A continuous variable valve duration apparatus may include a camshaft, a cam unit 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 inner bracket transmitting rotation of the camshaft to the cam unit, a wheel housing in which the inner bracket is rotatably inserted, on which a guide groove parallel to the camshaft is formed, and on which a guide hole vertical to the camshaft is formed, a guide portion including a guide shaft inserted into the guide hole for guiding movement of the wheel housing and 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.