Variable Valve Dual Gate Spring Design for Exhaust NVH Control
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Solution Overview
Problem
Existing variable valves in exhaust systems face issues with precise control of flow rate and noise reduction due to deteriorating spring properties at high temperatures, leading to interference with peripheral components and abnormal noise, and struggle to efficiently manage noise, vibration, and harshness (NVH) performance across varying vehicle conditions.
Innovation Solution
A variable valve design utilizing two independently controlled gates with flat springs of different spring constants, where the first gate has a greater spring constant than the second gate, and both are supported by 'C'-shaped flat springs with bent portions to prevent excessive deformation and control flow rates based on vehicle conditions, enhancing durability and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single torsion spring is used to control the gate opening, then the structure is simple, but the flow rate control precision deteriorates under varying vehicle conditions
Solution Approach 1:
The single gate is divided into two separate gates (first gate and second gate), each controlled by its own spring (first spring and second spring). This segmentation allows independent control of different gate sections, enabling more precise flow rate adjustment across varying vehicle conditions while maintaining manageable structural complexity
Solution Approach 2:
The spring constants of the first and second springs are designed to be different, allowing dynamic adaptation to varying exhaust gas flow conditions. The first gate with its spring opens at different flow rates than the second gate, creating a dynamic, multi-stage control system that optimizes performance across the full range of vehicle operating conditions
2Productivity
If the gate is opened to a large degree to improve exhaust performance, then exhaust efficiency improves, but interference with peripheral components occurs
Solution Approach 1:
The opening action is segmented into two stages: the first gate opens partially to provide moderate exhaust flow improvement, and the second gate opens additionally when flow rates are higher. This segmented approach achieves exhaust performance enhancement without requiring a single gate to open to a large degree, thereby avoiding interference with peripheral components
Solution Approach 2:
The first gate is designed to open partially under normal operating conditions to provide sufficient exhaust efficiency improvement, while the second gate provides additional opening capability when higher flow rates are needed. This partial action approach achieves the necessary performance without excessive gate opening that would cause interference
3Reliability
If a coil-shaped torsion spring is used to support the gate, then the gate can be supported, but abnormal noise occurs due to rattling and collision
Solution Approach 1:
The coil-shaped torsion spring is replaced with flat springs (first spring and second spring) that have a more stable contact interface with the gates. The flat spring design provides durable support while eliminating the rattling and collision noises associated with coil springs, as the flat configuration maintains consistent contact without lateral movement or vibration
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
This design allows for precise control of exhaust gas flow rates, improving NVH and power performance by independently managing gate openings based on vehicle idling and traveling conditions, reducing noise and interference, and maintaining durability through controlled elastic deformation.
Implementation Method 1
a first spring mounted on the housing to apply elastic force in a direction in which the first gate is closed, a second spring mounted on the housing to apply elastic force in a direction in which the second gate is closed
Implementation Method 2
the variable valve is operated so that the gate 2 is opened when pressure of exhaust gas exceeds elastic force of the torsion spring 3
Data Source
AI summary
A variable valve may include a housing having hinge support portions protruding from a first side thereof, and an opening at a second side thereof, a first gate rotatably coupled to the hinge support portions so as to open and close a part of the opening, a first spring mounted on the housing to apply elastic force in a direction in which the first gate is closed, a second gate rotatably coupled to the hinge support portions so as to open and close a remaining part of the opening, and a second spring mounted on the housing to apply elastic force in a direction in which the second gate is closed, in which the first spring and the second spring may have different spring constants.