Vehicle Air Intake Drum Flap Noise Damping
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Solution Overview
Problem
Vehicle air conditioning units generate noise that is amplified and spread throughout the passenger compartment due to the design of fresh and recirculation air inlets, which affects the comfort and efficiency of the air conditioning system.
Innovation Solution
An air intake device with rotatable drum flaps and elastic means that modulate the flow between fresh and recirculation air inlets, combined with a noise damping grille and deflector cap to reduce noise and enhance air conditioning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the recirculation air inlet is turned backwards towards the passenger compartment to allow easy air transfer, then the air flow efficiency is improved, but the noise generated by the fan and air conditioning unit is amplified and spread throughout the passenger compartment
Solution Approach 1:
The recirculation air inlet is divided into two separate inlets (first and second recirculation air inlets) positioned at different locations and orientations. This segmentation allows each inlet to be optimized for different functions: one for efficient air intake and another for noise reduction, resolving the contradiction between flow efficiency and noise control.
Solution Approach 2:
Different regions of the air intake device are given different properties: the first recirculation air inlet is oriented backwards for efficient air transfer, while the second recirculation air inlet is oriented forward and equipped with noise damping grilles for noise reduction. This local differentiation allows simultaneous optimization of both air flow efficiency and noise control in different parts of the system.
2Productivity
If the fresh air inlet faces forward to allow easy transfer of outside air, then the air intake efficiency is improved, but the device complexity increases due to the need for drum flaps and elastic means to modulate flow between fresh and recirculation air
Solution Approach 1:
Multiple functions are merged into a single integrated device: the casing incorporates both fresh air inlet and recirculation air inlets, drum flaps for flow modulation, elastic means for automatic positioning, and noise damping grilles. This consolidation achieves efficient air intake with multiple functions while avoiding the complexity of separate independent systems.
Solution Approach 2:
The drum flaps are designed to be rotatable and movable between different positions (fresh air extreme position and recirculation extreme position), allowing dynamic adjustment of air flow distribution. The elastic means provide automatic dynamic positioning of the flaps based on pressure differentials, enabling adaptive flow control without complex mechanical actuators.
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 reduces noise perception inside the vehicle while increasing the air conditioning unit's performance by optimizing air flow and sound wave interference, allowing for improved comfort and efficiency.
Implementation Method 1
between the drum flaps there are interposed elastic means by means of which one of the drum flaps is capable of driving the other of the drum flaps during rotation motion
Implementation Method 2
This expedient allows to further reduce the noise, thanks to the reflection and the reciprocal interference of the sound waves achieved due to the walls of the openings of the damping grille
Data Source
AI summary
Described herein is an air intake device for an air conditioning unit of a vehicle, the air intake device including a casing on which there are formed a fresh air inlet, a recirculation air inlet, and an air outlet adapted to be associated to an air inlet of a blower of the air conditioning unit, and a pair of drum flaps mounted to the casing and rotatable about a common rotation axis and movable between a fresh air extreme position and a recirculation extreme position. In the fresh air extreme position, the angular span of the recirculation air inlet is partially covered by one of the drum flaps and partially covered by the other of the drum flaps, and in the recirculation extreme position, the angular span of the fresh air inlet is completely covered by one of the drum flaps, the drum flaps overlapping each other.