Variable Valve Duration Cam Assembly for Noise and Vibration Reduction
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Solution Overview
Problem
Existing engine valve systems face challenges in optimizing valve operation based on engine speed, leading to inefficiencies in noise and vibration reduction, and require complex modifications for optimal performance.
Innovation Solution
A continuous variable valve duration apparatus with a camshaft, guide shaft, worm wheel, and wheel elastic portion that allows for adjustable valve opening duration based on engine conditions, reducing noise and vibration through a simple and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex modifications are made to achieve optimal valve operation, then valve performance can be optimized, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention integrates multiple functions into a single modular assembly. The wheel housing simultaneously serves as a support structure for the cam unit, a movable platform for duration adjustment, and a connector between the camshaft and follower. The cam unit itself is designed to accommodate variable engagement lengths, allowing the same basic structure to provide both timing and duration control. This multi-functionality reduces the need for separate complex mechanisms.
Solution Approach 2:
The invention employs a nested structure where the cam unit is housed within the wheel housing, which in turn is mounted on the camshaft. The follower is positioned to engage with the cam unit through the wheel housing structure. This nesting allows compact integration of multiple components and simplifies the overall system architecture, reducing manufacturing complexity while maintaining optimization capabilities.
2Reliability
If valve operation is optimized for specific engine speeds, then performance improves at those speeds, but noise and vibration increase due to non-optimal operation at other speeds
Solution Approach 1:
The invention enables continuous change of the valve opening duration parameter according to engine operating conditions. By adjusting the effective cam engagement length through wheel housing displacement, the system can optimize valve duration for different engine speeds and loads. This continuous parameter adjustment prevents suboptimal valve operation that would otherwise generate excessive noise and vibration, allowing the engine to maintain smooth operation across the entire operating range.
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 effectively varies valve opening duration according to engine operation conditions, reducing noise and vibration while minimizing production costs and enhancing productivity by integrating with existing engines without extensive modifications.
Implementation Method 1
a guide shaft on which a guide screw thread is formed and disposed perpendicular to the camshaft
Implementation Method 2
a worm wheel to which an inner screw thread configured to engage with the guide screw thread is formed therewithin
Implementation Method 3
a wheel elastic portion mounted to the wheel housing to push the worm wheel toward the guide shaft and the control shaft
Data Source
AI summary
A continuous variable valve duration apparatus includes a cam unit, a cam formed on the cam unit, a camshaft inserted into the cam, a guide bracket, a guide shaft mounted on the guide bracket and disposed perpendicular to the camshaft, wherein a guide screw thread is formed on the guide shaft, a wheel housing disposed within the guide bracket, an inner wheel rotatably inserted into the wheel housing and movable perpendicular to the camshaft, a worm wheel disposed within the wheel housing, wherein an inner screw thread configured to engage with the guide screw thread is formed inside the worm wheel and an outer screw thread is formed on the worm wheel, a control shaft, a control worm formed on the control shaft, and a wheel elastic portion mounted to the wheel housing.