Vehicle HVAC Inlet Geometry for Air Backflow Noise Reduction
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Solution Overview
Problem
The challenge is to reduce noise caused by air backflow in the inlet portion of a vehicle air conditioning device while minimizing its size, which is exacerbated by pressure loss through the evaporator and heater core.
Innovation Solution
A vehicle air conditioning device with a flow path width adjusting unit that inclines and narrows the inlet portion of the blowing flow path, moving the air inlet away from the nose portion where backflow occurs, and using a plate or block material to adjust the flow path width without obstructing airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the outer shape of the vehicle air conditioning device is made small to secure space, then the device size is reduced, but air backflow occurs in the inlet portion causing noise increase
Solution Approach 1:
The patent applies local quality by modifying only the inlet portion geometry with an inclined surface and flow path width adjusting unit, while keeping the rest of the compact housing design intact. This localized modification addresses the backflow issue without compromising the overall size reduction goal
Solution Approach 2:
The patent introduces a flow path width adjusting unit that modifies the flow path cross-sectional area in the width direction, adding a dimensional control mechanism to manage airflow characteristics without increasing the front-rear length of the device
2Object-affected harmful factors
If the inlet portion of the blowing flow path is made wider to prevent backflow, then noise from backflow is reduced, but the device size increases
Solution Approach 1:
The patent changes the geometric parameters of the inlet portion by introducing an inclined surface and a flow path width adjusting unit that modifies the cross-sectional area distribution. This parameter optimization allows effective backflow prevention within the constrained device volume
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 effectively reduces noise from air backflow while maintaining the device's compact size without impairing cooling performance.
Implementation Method 1
an evaporator that generates cold air by cooling the air blown from the blowing fan
Implementation Method 2
a heater core that generates warm air by warming the cold air
Data Source
AI summary
This air-conditioning device (10) for a vehicle comprises a flow path width adjustment portion (14) that is provided at an inlet portion (11BA) of a ventilation flow path (11B) so as to be connected to the inner surface (31a) of a first side wall (31), the flow path width adjustment portion (14) having an upper end connected to a fan mounting portion (35), extending downward, and being located between a third wall (33) and a nose portion (37) in the (Y) direction. The nose portion (37) has an inclined portion (37A) that is inclined with respect to the third wall (33) such that the width of the inlet portion (11BA) increases in the (Z) direction from the inlet to the outlet of the inlet portion (11BA) of the ventilation flow path (11B). In the (Z) direction, the flow path width adjustment portion (14) is formed so as to narrow the width of the inlet portion (11BA) of the ventilation flow path (11B) in the (Y) direction.