Variable Valve Lift Apparatus with Eccentric Cam Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional valve lift apparatuses have a fixed valve lift amount due to a fixed cam shape, making them inadequate for adjusting gas introduction or exhaust at varying engine speeds, leading to insufficient valve operation at low or high speeds.
Innovation Solution
A variable valve lift apparatus with an output cam driving unit, an output cam, an output cam position controlling unit, and a valve opening unit, utilizing eccentric shafts, connecting links, and guide rollers to adjust valve lift and timing, allowing for compact and efficient operation across different engine performance modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed cam shape is used in the valve lift apparatus, then the structure is simple, but the valve lift amount cannot be adjusted for different engine speeds
Solution Approach 1:
The patent implements a dynamically adjustable valve lift system where the output cam's rotational position can be continuously varied by the output cam position controlling unit. This allows the valve lift amount to be adapted to different engine speeds and operating conditions, transforming a static fixed-lift system into a dynamic variable-lift system that optimizes performance across the entire operating range.
Solution Approach 2:
The valve lift apparatus is divided into distinct functional modules: the output cam driving unit, the output cam, the output cam position controlling unit, and the valve opening unit. This segmentation allows each component to be optimized independently and facilitates the complex motion control needed for variable valve lift while maintaining manageable system complexity.
2Adaptability or versatility
If the valve lift apparatus is designed for low driving speeds, then low-speed performance is improved, but valve operation is insufficient for high speeds
Solution Approach 1:
By enabling continuous adjustment of the output cam's rotational position, the system can dynamically adapt valve lift characteristics to match different engine speeds. This ensures reliable valve operation whether the engine is operating at low speeds requiring gentler valve motion or at high speeds requiring more aggressive valve opening, eliminating the need for speed-specific designs.
3Adaptability or versatility
If the valve lift apparatus is designed for high driving speeds, then high-speed performance is improved, but valve operation is insufficient for low speeds
Solution Approach 1:
The variable valve lift mechanism allows the system to switch between high-performance characteristics for high-speed operation and gentler characteristics for low-speed operation by adjusting the output cam position. This dynamic adaptability ensures the valve train operates reliably across the entire speed range without being optimized for only one extreme.
4Device complexity
If a compact scheme with small number of elements is used, then device complexity is reduced, but achieving variable valve lift and timing control becomes difficult
Solution Approach 1:
The output cam serves multiple functions: it converts rotational motion to reciprocating valve motion, provides variable valve lift through position adjustment, and enables timing control through rotational phase variation. The output cam position controlling unit simultaneously manages both lift amount and timing, reducing the need for separate mechanisms and achieving compact design without sacrificing control 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
Enables adjustable valve lift and timing, improving engine performance by optimizing gas exchange at various speeds through a compact and reliable mechanism, enhancing durability and adaptability.
Implementation Method 1
a first eccentric shaft configured to transmit the rotation to the output cam; and a first connecting link configured to connect the first eccentric shaft with the output cam
Implementation Method 2
a second eccentric shaft configured to control the position of the controlling body; and a second connecting link connecting the second eccentric shaft with the controlling body
Implementation Method 3
The guide portion may include a plurality of guide rollers that contacts at least a lateral surface of the controlling body
Implementation Method 4
The output cam driving unit may further include an output cam elastic portion making restoring force to the output cam toward the input cam to facilitate the input cam to contact the input cam contact roller
Implementation Method 5
The controlling unit may further include a controlling body elastic portion making restoring force to the controlling body toward the controlling cam to facilitate the controlling cam to constantly contact the controlling cam contact roller
Data Source
AI summary
The present invention relates to a continuously variable valve lift apparatus that includes an output cam driving unit for transmitting a rotation, an output cam that receives the rotation from the output cam driving unit and rotates about an axis at a predetermined angle, an output cam position controlling unit for controlling the axis of rotation of the output cam, and a valve opening unit that is operated by the output cam.