Variable Valve Lift Apparatus Single Cam Roller Mechanism
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Solution Overview
Problem
Existing variable valve lift systems require multiple cams to achieve optimal valve operation at varying engine speeds, leading to complex configurations and increased costs due to potential interferences and the need for additional operating elements.
Innovation Solution
A variable valve lift apparatus that utilizes a single cam to change valve lift through a lever body with a piston, hydraulic pressure chamber, and roller mechanism, allowing for two-stage lift adjustment with minimal components and reduced friction, using a hydraulic pressure supply and elastic member for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple cams are provided to the cam shaft for variable valve lift, then valve operation can be optimized for different engine speeds, but the configuration becomes complicated and interference among elements occurs
Solution Approach 1:
A single cam is designed to perform multiple functions by varying the roller's position along the cam's circumference. The roller can be positioned at different radial distances from the cam center, allowing one cam to provide multiple valve lift characteristics (different engine speed optimizations) without requiring multiple separate cams.
Solution Approach 2:
The roller's position is made dynamically adjustable through a piston-cylinder mechanism that can change the roller's radial position on the cam. This dynamic repositioning allows the system to adapt valve lift characteristics in real-time based on engine operating conditions, replacing the static multiple-cam approach.
2Reliability
If multiple cams are operated independently to prevent interference, then element interference is prevented, but additional operating elements are required and cost increases
Solution Approach 1:
Multiple cam functions are merged into a single cam structure. Instead of having separate cams that could interfere with each other, one cam integrates all valve lift functions, eliminating mechanical interference risks while reducing the number of operating elements required.
Solution Approach 2:
The single cam is designed with varying radial profiles that allow it to universally serve multiple valve lift requirements. The roller's adjustable position enables one cam to replace multiple specialized cams, reducing component count and simplifying the operating mechanism.
3Device complexity
If a single cam is used for variable valve lift, then configuration is simplified and cost is reduced, but the ability to change valve lift must be achieved through additional mechanisms
Solution Approach 1:
A piston-cylinder mechanism dynamically adjusts the roller's radial position on the cam, enabling variable valve lift from a single cam. This dynamic adjustment capability compensates for the simplicity of using one cam, maintaining adaptability while simplifying the overall configuration.
Solution Approach 2:
The roller acts as an intermediary between the single cam and the valve. By adjusting the roller's position on the cam, the system mediates between the cam's fixed profile and the required variable valve lift, achieving adaptability through a simple intermediate mechanism.
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 simplifies configuration, minimizes power loss due to friction, and reduces costs by using fewer components while maintaining efficient valve operation across different engine speeds.
Implementation Method 1
a hydraulic pressure supply portion selectively supplying hydraulic pressure to the hydraulic pressure chamber for moving the piston in a second end direction of the lever body
Implementation Method 2
an elastic member arranged in the lever body and elastically biasing the active portion toward a first end direction of the lever body for returning the piston to an original position when the hydraulic pressure being supplied to the hydraulic pressure chamber is removed
Data Source
AI summary
A variable valve lift apparatus for changing a lift of an intake or exhaust valve in at least two stages may include a lever body, a piston, a cylinder, a hydraulic pressure chamber, an active portion, a hinge portion, a roller, a rotation shaft, a guide slot, a hydraulic pressure supply portion, and an elastic member, in which the lever body may make a lever motion at an end with the intake valve or the exhaust valve connected thereto, the piston may make reciprocal motion in the cylinder, the rotation shaft may pass through the hinge portion and the roller and be a rotation center of the roller, moving together with the roller, the hydraulic pressure supply portion may supply hydraulic pressure to the hydraulic pressure chamber for moving the piston, and the elastic member may return the piston if the hydraulic pressure being supplied to the hydraulic pressure chamber is removed.