Tunable Sound Transmission Device for Motor Vehicles
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Solution Overview
Problem
Modern motor vehicles with smaller engines and lighter designs often have reduced engine sound levels, which can be obscured by other noises, making it desirable to enhance the transmission of engine sound to the passenger compartment while maintaining airflow isolation and allowing for user-tunable sound frequency and dampening.
Innovation Solution
A tunable sound transmission device with a flexible membrane to isolate airflow and a replaceable sound characterization device, such as polyurethane foam, to adjust the frequency spectrum and overall sound dampening level, allowing end-users to customize the engine sound experience without active electronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the sound transmission device transmits engine sound to the passenger compartment, then the engine sound amplitude level is improved, but airflow isolation is compromised allowing unfiltered air intake
Solution Approach 1:
The sound transmission device is segmented into distinct functional sections: a sound transmission tube for acoustic signal propagation, and a flexible diaphragm section for airflow isolation. This segmentation allows the device to simultaneously transmit engine sound while preventing unfiltered air intake, resolving the contradiction between sound transmission and airflow isolation.
Solution Approach 2:
A flexible diaphragm is introduced as an intermediary element within the sound transmission tube. This diaphragm acts as a mediator that permits acoustic wave transmission while blocking airflow, thereby enabling sound transmission without compromising airflow isolation and preventing unfiltered air from entering the air intake tract.
2Adaptability or versatility
If passive tuning devices (quarter wave tuner or resonator chamber) are added to the sound transmission tubing, then the transmitted sound spectrum can be tailored, but the device complexity increases
Solution Approach 1:
The patent utilizes parameter changes in passive acoustic elements (quarter wave tuner length, resonator chamber volume) to achieve sound spectrum tuning. By adjusting these physical parameters, different frequency ranges can be amplified or attenuated, providing versatile sound customization without requiring complex active electronic systems.
Solution Approach 2:
The patent employs mechanical vibration principles through quarter wave tuners and resonator chambers to passively amplify or attenuate specific engine sound frequencies. These passive acoustic devices utilize resonance and standing wave phenomena to tailor the transmitted sound spectrum, achieving adaptability while maintaining relatively simple device architecture.
3Object-affected harmful factors
If the sound transmission tube is extended into the vehicle interior, then the transmitted engine sound amplitude level is improved, but the device length increases
Solution Approach 1:
The patent transitions the sound transmission path from a purely linear extension into the vehicle interior to a three-dimensional routing that may travel along the vehicle's firewall or other structural surfaces. This dimensional change allows the sound transmission tube to reach the passenger compartment while minimizing visual prominence and optimizing space utilization, effectively managing the length constraint.
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
Enables effective transmission of engine sound with customizable frequency response and sound level, enhancing the driving experience by allowing users to personalize the sound characteristics without the need for complex active systems, while maintaining airflow isolation and preventing unfiltered air intake.
Implementation Method 1
A flexible membrane is positioned to sealably close off a portion of the transmission line thereby dividing the transmission line into two portions that are airflow isolated from each other
Implementation Method 2
The membrane, thus installed, is operable to communicate sound between the portions while preventing airflow between the portions
Implementation Method 3
The sound characterization device is configured and adapted to provide an intended frequency dependent sound attenuation characteristic and an overall sound dampening level for the sound transmission device
Implementation Method 4
The sound characterization device is tunable by replacing the sound characterization device with another sound characterization device configured and adapted to provide at least a differing one of the transmitted sound spectral frequency response and desired overall sound dampening level
Data Source
AI summary
A tunable sound transmission device for transmitting an engine rumble sound into an interior of a motor vehicle includes a transmission line having a first end in acoustic communication with an air intake tract of an engine. A flexible membrane is positioned to sealably close off a portion of the transmission line thereby dividing the transmission line into two portions that are airflow isolated from each other. A receptacle is arranged at the second end of the transmission line and a user changeable sound characterization device is replaceably installed into the receptacle. The sound characterization device is configured and adapted to provide an intended frequency dependent sound attenuation characteristic and an overall sound dampening level for the transmitted engine sound.