Vehicle Intake Valve Flap With Cam-Leaf Spring NVH Control
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Solution Overview
Problem
Existing variable valve devices in vehicle air intake systems face challenges in simultaneously delaying the opening time of the valve in low RPM ranges to improve NVH performance and fully opening the valve with maximum air flow, while also being cost-effective and reliable, due to limitations with coil springs and magnets.
Innovation Solution
A variable valve device using a cam protrusion and a leaf spring to control the opening and closing of the valve, allowing for delayed opening in low RPM ranges and rapid full opening in high RPM ranges, improving NVH performance and engine power while reducing costs compared to coil spring or magnet-based systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a coil spring with increased spring constant is used to delay the opening time of the variable valve, then NVH performance is improved, but the valve cannot be fully opened with maximum air flow
Solution Approach 1:
The patent employs a dynamic opening mechanism where the valve opening timing and degree are not fixed but vary with engine operating conditions. The variable valve device responds to changing intake pressure dynamics, automatically adjusting the valve opening characteristics to achieve both NVH improvement at low RPM and maximum air flow at high RPM
Solution Approach 2:
The system changes the operational parameters of the valve mechanism based on engine RPM and intake pressure conditions. By varying the effective spring constant or opening force parameters dynamically rather than using a fixed spring constant, the system resolves the contradiction between delayed opening (for NVH) and full opening (for air flow)
2Productivity
If a coil spring with reduced spring constant is used to fully open the variable valve with maximum air flow, then air flow is improved, but the opening time is advanced causing degraded NVH performance
Solution Approach 1:
The valve mechanism transitions from static spring-based operation to dynamic pressure-responsive operation. The intake pressure itself becomes the actuating force, allowing the valve to fully open at high RPM without being constrained by a fixed spring constant that would compromise NVH performance
3Stability of the object's composition
If magnets with increased distance between them are used to reduce changes in magnetic force, then control stability is improved, but costs increase due to requirement of magnets with high magnetic flux density
Solution Approach 1:
The patent extracts the magnetic components from the variable valve device entirely, replacing them with a purely mechanical spring-based actuation system. This eliminates the need for magnets and their associated cost and stability management issues, while achieving the desired valve control through intake pressure and spring constant optimization
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 device effectively improves NVH performance in low RPM ranges and increases engine power in high RPM ranges by adjusting the opening time of the valve, while enhancing operational reliability and reducing costs through the use of a cam protrusion and leaf spring mechanism.
Implementation Method 1
a cam protrusion and a leaf spring provided on the variable valve flap and the variable valve housing, respectively, to be in contact with each other
Data Source
AI summary
An embodiment variable valve device of a vehicle intake system includes a variable valve housing fixed to a housing of an air cleaner and including a valve passage penetrating the air cleaner, a variable valve flap rotatably coupled to the variable valve housing and configured to perform opening and closing operations based on an intake negative pressure of an engine to open and close the valve passage, and a cam protrusion and a leaf spring provided on the variable valve flap and the variable valve housing, respectively, wherein the cam protrusion and the leaf spring are in contact with each other.