Convex Grid Rotary Door for HVAC Turbulence Reduction
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Solution Overview
Problem
Existing fresh air/recirculation air switching systems in automotive HVAC systems using rotary doors often create turbulent air flow and noise due to the design of the arc-shaped circumferential wall, which prior solutions have not fully addressed, complicating manufacturing and reducing production efficiency.
Innovation Solution
A rotary door with an arc-shaped circumferential wall and a convex arc-shaped grid protruding from its inner surface, creating an oval cross-section that eliminates turbulent air flow and noise by occupying the space underneath the wall, improving airflow distribution and reducing noise in the vehicle cabin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a rotary door with arc-shaped circumferential wall is used to switch fresh air and recirculation air, then the packaging space is reduced, but turbulent air flow and noise are generated underneath the circumferential wall
Solution Approach 1:
The invention adds a third dimension to the rotary door structure by introducing a convex grid portion that protrudes from the inner surface of the circumferential wall. This creates a three-dimensional convex structure that occupies the space underneath the circumferential wall, preventing turbulent air flow from forming in that region while maintaining the compact packaging design.
Solution Approach 2:
The invention converts the potentially harmful turbulent air flow underneath the circumferential wall into a beneficial structured flow pattern. The convex grid portion guides the air flow through defined pathways, transforming the chaotic turbulence into controlled, laminar flow that reduces noise while still allowing air to pass through the rotary door structure.
2Object-generated harmful factors
If a convex surface is added under the circumferential wall to eliminate turbulence, then noise is reduced, but manufacturing complexity increases
Solution Approach 1:
The invention merges the convex grid portion with the rotary door body into a single integrated structure. By forming the convex grid as an integral part of the rotary door during the molding process, the design achieves noise reduction without requiring separate manufacturing steps or assembly operations, thereby maintaining manufacturing simplicity.
Solution Approach 2:
The invention uses a convex grid pattern with curved surfaces that can be efficiently formed through plastic injection molding or similar curvilinear forming processes. The convex shape is optimized for moldability, allowing the complex three-dimensional structure to be manufactured in a single step using standard automotive HVAC manufacturing techniques.
3Ease of manufacture
If an integrally molded rotary door with convex grid is used, then manufacturing is simplified, but manufacturing precision requirements increase
Solution Approach 1:
The invention segments the rotary door into functional zones: the arc-shaped circumferential wall for air switching, the convex grid portion for turbulence prevention, and the opening/closing mechanism. This functional segmentation allows each zone to be optimized independently for its specific purpose while being manufactured as a single integrated part, balancing manufacturing efficiency with quality control.
Solution Approach 2:
The invention optimizes the geometric parameters of the convex grid portion, including the height, width, and spacing of the grid elements, to achieve effective turbulence prevention while maintaining manufacturability. These parameters are carefully selected to ensure that the structure can be formed with standard molding tolerances while achieving the desired airflow control performance.
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 solution effectively reduces noise and improves airflow distribution across the blower fan, increasing efficiency and simplifying manufacturing by allowing for an integrally molded single piece design, which enhances the overall performance of the HVAC system.
Implementation Method 1
the flow of the air creates a turbulent pocket underneath the circumferential wall of the rotary door which causes unwanted noise
Data Source
AI summary
A fresh air and recirculation air switching case using a rotary door, since an introduced air flows along an inner surface of a circumferential wall of the rotary door, a convex grid is formed on an inner surface of the circumferential wall of the rotary door. In this system, the air flow directed toward a suction inlet is prevented from becoming turbulent behind the rotary door and the air flow noise can be suppressed.