Micro Perforated Panel Sound Damper for HVAC Noise Reduction
Solution Overview
Problem
HVAC systems in vehicles, particularly electric vehicles, generate noticeable noise due to blower fan operation and aerodynamic changes, which is not masked by the absence of an internal combustion engine, leading to discomfort for occupants.
Innovation Solution
A sound damper system comprising a micro perforated panel (MPP) attached to the HVAC module's passage wall, with a cavity on the opposite side and a non-perforated film covering the MPP, to dissipate acoustic energy and reduce noise levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a blower fan is used to circulate air through the HVAC system, then air circulation is achieved, but noise is generated
Solution Approach 1:
The noise-generating blower fan is extracted from the vehicle HVAC system and replaced with a cabin air intake system that utilizes the vehicle's forward motion to draw air through the HVAC system, eliminating the primary noise source while maintaining air circulation functionality
Solution Approach 2:
The mechanical blower fan system is replaced with an aerodynamic system that uses the vehicle's motion through air to create the necessary airflow, substituting mechanical noise-generating components with a quieter aerodynamic solution
2Volume of moving object
If HVAC packaging space is reduced, then vehicle design flexibility is improved, but noise control becomes more difficult
Solution Approach 1:
The air intake system utilizes the vehicle's forward motion through space to generate airflow, effectively using the vehicle's movement as a dimension to solve the noise problem without requiring additional HVAC packaging space
Solution Approach 2:
The system changes the operating parameters by eliminating the need for high-speed blower operation, using instead the vehicle's forward velocity to drive air through the HVAC system at lower noise-generating speeds
3Use of energy by moving object
If electric vehicle HVAC systems operate without engine noise masking, then energy efficiency is improved, but HVAC noise becomes more noticeable
Solution Approach 1:
The noise-generating blower fan is removed from the system, eliminating the primary source of HVAC noise that would otherwise be audible in the quiet electric vehicle cabin environment
Solution Approach 2:
The mechanical blower system is replaced with an aerodynamic air intake system that uses vehicle motion to drive airflow, significantly reducing mechanical noise while maintaining the energy-efficient operation characteristic of electric vehicles
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 sound damper effectively reduces overall noise levels by converting sound energy into heat, providing broadband noise reduction without disrupting air flow, even at higher blower speeds, and is applicable in various air flow settings beyond HVAC systems.
Implementation Method 1
The sound damper effectively reduces overall noise levels by converting sound energy into heat
Implementation Method 2
The sound damper effectively reduces overall noise levels by converting sound energy into heat
Implementation Method 3
a micro perforated panel (MPP) attached to a passage wall that defines a passageway configured to facilitate pressurized air flow therein, the MPP and a back wall (e.g., dash wall) collectively defining a cavity located outside the passageway
Data Source
AI summary
A sound damper and associated system are disclosed for damping sound. In embodiments, the sound damper is utilized within an automotive HVAC system. A passage wall defines an air passageway that transmits air. The sound damper includes a micro perforated panel (MPP) located within an opening formed into a passage wall. A back wall is spaced from the MPP, and a cavity is provided between the back wall and the MPP that is outside the air passageway. In embodiments, the MPP can be covered by a non-perforated film that is acoustically transparent and air impermeable.