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, making them inefficient for optimizing valve operation based on engine speed, particularly in reducing weight and driving resistance.
Innovation Solution
A continuous variable valve duration system with a camshaft, variable phase first cam, inner bracket, slider housing, rocker shaft, and control portion, allowing for adjustable valve opening duration through a simple construction that reduces engine size and production costs.
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 the construction becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent combines the functions of variable valve lift and variable valve timing into a single camshaft mechanism. The cam profile directly controls both the lift amount and the duration of valve opening by varying the pressure angle, eliminating the need for separate CVVL and CVVT mechanisms. This merging of functions reduces overall system complexity while maintaining adaptability for optimal valve operation across different engine speeds
Solution Approach 2:
The cam profile is designed with dynamic characteristics where the pressure angle varies continuously along the cam rotation. By adjusting the pressure angle within a specific range (15-45 degrees), the system dynamically changes both valve lift and duration simultaneously. This dynamic control approach allows optimal valve operation at different engine speeds without requiring multiple discrete mechanisms
2Adaptability or versatility
If existing engines are modified to implement variable valve control systems, then valve operation can be optimized, but the modification becomes excessive and costly
Solution Approach 1:
The patent employs a cost-effective cam profile design that can be manufactured using conventional cam manufacturing processes. The cam profile geometry is optimized to provide variable duration and lift functions without requiring expensive additional components or complex assembly procedures. This approach makes the system economically viable for production while avoiding excessive modification costs
Solution Approach 2:
The single camshaft mechanism performs multiple functions simultaneously: it controls valve lift, valve timing, and valve duration all through one component. This multi-functionality eliminates the need for separate mechanisms and reduces the overall number of parts required, thereby simplifying manufacturing and reducing production costs while maintaining optimal valve operation capability
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 system effectively varies valve opening duration based on engine conditions, reducing engine weight, driving resistance, and production costs while maintaining optimal valve operation without excessive modification to existing engines.
Implementation Method 1
intake valves are operated by a camshaft in order to intake the air
Implementation Method 2
the control portion may include a control shaft and an eccentric shaft inserted into the control slot and eccentrically formed to the control shaft
Data Source
AI summary
A continuous variable valve duration system may include a camshaft, and a first cam portion including a first cam. The camshaft is inserted in the first cam portion. A relative phase angle of the first cam with respect to the camshaft is variable. The system may further include an inner bracket transmitting rotation of the cam shaft to the first cam portion, a slider housing in which the inner bracket is rotatably inserted and movable along a predetermined first direction, a rocker shaft, a first rocker arm rotatably disposed to the rocker shaft of which a first end contacts with the first cam and of which a second end is connected to a first valve, an upper housing connected with the slider housing and relatively movable with respect to the slider housing along a second direction vertical to the first direction and a control portion selectively moving the upper housing.