Centrifugal Blower Intake Layout for Low-Resistance Two-Layer Airflow
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Solution Overview
Problem
The existing centrifugal blower for two-layer flow air conditioning systems in vehicles experiences high air-flow resistance when introducing external air, leading to reduced flow volume and inadequate prevention of fog on windows during heating mode.
Innovation Solution
The centrifugal blower design reduces the directional change of external air between the air intake housing and the scroll housing by using a separation cylinder with a gradually changing cross-sectional shape and strategically positioned switching doors, minimizing air-flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external air passes through a space outside the separation cylinder and its direction is changed toward the front of the vehicle, then the centrifugal blower can separate internal and external air flows, but the large change in flow direction increases air-flow resistance against external air
Solution Approach 1:
The separation cylinder is designed with a curved surface that gradually changes the flow direction of external air from downward to forward direction. This curved geometry reduces abrupt directional changes and minimizes air-flow resistance while maintaining effective separation between internal and external air streams.
Solution Approach 2:
The cross-sectional area of the separation cylinder is varied along its length to optimize flow characteristics. By changing the geometric parameters of the separation cylinder, the patent achieves gradual flow direction change and reduced resistance while maintaining separation effectiveness.
2Reliability
If the centrifugal blower fails to suck external air enough during internal/external air two-layer flow mode, then the air flow separation may be compromised, but internal air could penetrate the upper passage for external air
Solution Approach 1:
The air intake housing is divided into separate regions for internal air and external air intake, with dedicated suction ports and flow paths. This segmentation ensures that external air is adequately drawn in through its own dedicated path while maintaining clear separation from internal air, preventing penetration and mixing.
Solution Approach 2:
The separation cylinder acts as an intermediary structure that mediates between the external air flow path and the internal air flow path. It physically separates the two streams while allowing both to be drawn into the impeller region, ensuring adequate external air intake while maintaining separation.
3Productivity
If internal air and external air are both sucked into the air intake housing at the same time, then the centrifugal blower can provide sufficient air flow volume, but the air flows may mix before reaching the scroll housing
Solution Approach 1:
The air intake housing incorporates distinct intake ports and separated flow channels for internal air and external air. This segmentation allows both air sources to be drawn simultaneously with adequate flow volumes while maintaining physical separation throughout the flow path until discharge.
Solution Approach 2:
The internal air passage and external air passage are designed with asymmetric configurations and different flow paths within the air intake housing. This asymmetric design ensures that despite both air streams being present simultaneously, they follow distinct trajectories that prevent mixing while maintaining sufficient flow volumes for both.
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 efficient introduction of external air, preventing internal and external air mixing and effectively preventing window fogging during heating mode by reducing air-flow resistance.
Implementation Method 1
the mainstream of external air having been sucked into the air intake housing from the front of the vehicle in a rearward direction passes through a space outside the separation cylinder in a downward direction and then its direction is changed toward the front of the vehicle by the separation cylinder
Implementation Method 2
external air passes through the outside of the separation cylinder and then blows out into the upper passage of the scroll housing through an upper half part of an impeller, and internal air passes through the inside of the separation cylinder and then blows out into the lower passage of the scroll housing through a lower half part of the impeller
Data Source
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AI summary
[Problem] To reduce the air-flow resistance against external air from an external air introduction port of an air intake housing to a scroll housing in a single-suction centrifugal blower for a vehicle equipped with a separation cylinder when the centrifugal blower operates in an internal/external air two-layer flow mode. [Solving Means] An external air introduction port (25) that introduces external air into an air intake housing (21A; 21B; 21C) when a centrifugal blower operates in a two-layer flow mode is located above a first internal air introduction port (26A) that introduces internal air into the air intake housing during the two-layer flow mode. When the centrifugal blower operates in the two-layer flow mode, internal air (AR) flows into a front region (212) of the air intake housing, which coincides with an opening region (240) of an inlet side end part (24) of a separation cylinder (14), through the first internal air introduction port (26A), and external air (AE) flows into a rear region (211) through the external air introduction port (25).