HVAC Diffuser VBC Receptacle for Air Flow Uniformity
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Solution Overview
Problem
Automotive HVAC systems face challenges in achieving uniform air flow distribution due to limitations in the molding process, which restricts the extension of vanes from the diffuser walls, leading to insufficient influence on air flow at the central portion and inefficiencies in evaporator performance and noise reduction.
Innovation Solution
A recessed receptacle in the diffuser wall is used to mount the VBC module's cooling fins, allowing them to protrude into the central air stream and function as vanes, with the option to place them horizontally in the outer peripheral wall to guide the flow, utilizing the Bernoulli Effect for improved flow manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vanes are extended from diffuser walls using conventional molding processes, then air flow near walls can be influenced, but vanes cannot extend from perpendicular walls and cannot effectively affect central air flow
Solution Approach 1:
The diffuser is divided into multiple moldable sections that can be assembled together. This segmentation allows vanes to be formed in separate moldable sections and assembled to create a complete circular array of vanes around the central air flow path, overcoming the limitation of conventional single-piece molding processes
Solution Approach 2:
The invention transitions from two-dimensional wall-mounted vanes to three-dimensional vanes that extend into the central air flow volume. The vanes are positioned to project into the central region of the diffuser, allowing them to influence the core air flow rather than only the boundary layer near walls
2Ease of manufacture
If the VBC module is mounted on a flat exterior surface of the diffuser wall, then mounting is simplified, but cooling fins cannot effectively interact with the diffused air stream
Solution Approach 1:
The VBC module with its cooling fins is nested within a receptacle formed in the diffuser wall. The receptacle is defined by cavities in the moldable sections, creating a recessed mounting space that allows cooling fins to extend into the diffused air stream while maintaining structural integration with the diffuser assembly
3Reliability
If cooling fins are positioned to extend into the central air stream, then cooling effectiveness is improved, but the molding process and part handling become more difficult
Solution Approach 1:
The diffuser is segmented into multiple moldable sections that can be separately formed and then assembled. This allows complex internal geometries including cavities for VBC mounting and support structures for central vanes to be created in manageable sections that are easier to mold and handle individually
Solution Approach 2:
The VBC module mounting receptacle and the diffuser structure are merged into an integrated assembly. The receptacle is formed as part of the moldable section geometry, combining the mounting function with the structural and aerodynamic functions of the diffuser
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 configuration enhances evaporator coverage, velocity distribution, pressure drop, and reduces aerodynamic noise by effectively directing the air flow through the integration of cooling fins as vanes within the diffuser.
Implementation Method 1
Cooling fins penetrate the diffuser wall so that they benefit from the air flow within the diffuser
Implementation Method 2
A variable blower control (VBC) module having a plurality of cooling fins
Implementation Method 3
utilizing the Bernoulli Effect for improved flow manipulation
Implementation Method 4
the diffuser turns the air stream for delivery to the evaporator. The blower/diffuser combination produces a high speed, non-uniform flow that tends to produce high flows on the outer periphery of the diffuser due to centrifugal forces
Data Source
AI summary
An automotive HVAC diffuser connects to a blower and a variable blower control (VBC) module having a plurality of cooling fins. An inlet receives air flow from the blower. An outlet is downstream from the inlet. An enclosed passageway is provided between the inlet and the outlet for forming a diffused air stream at the outlet. The enclosed passageway has a plurality of peripheral walls for guiding the air stream between the inlet and the outlet, including a curved outer peripheral wall corresponding to a region with a tendency for a high flow as a result of centrifugal effects. One of the peripheral walls includes a VBC receptacle formed as a depression into the peripheral wall having a substantially flat mounting surface and a first sloped side at an upstream end of the VBC receptacle to shape a portion of the diffused air stream. The flat mounting surface includes a plurality of cooling fin receiving slots arranged to receive the cooling fins, whereby the cooling fins extend into an interior of the diffused air stream.