Vehicle Sound Generator With Split Interior-Exterior Frequency Bands

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Solution Overview

Problem

Conventional vehicle sound generators for electric and hybrid vehicles cannot effectively replicate the deep pitch sounds of combustion engines due to their compact size and weatherproofing constraints, limiting their low-frequency response and failing to provide an engaging driving experience and adequate safety for pedestrians.

Innovation Solution

A vehicle sound generator system that utilizes both interior and exterior speakers, with the interior speaker producing low-frequency sounds below 300 Hz to leverage the vehicle's existing audio system and minimize attenuation, while the exterior speaker generates higher frequency sounds, enhancing the frequency response and replicating the sound of high-performance engines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a compact single-box speaker is used for exterior VSG output, then the speaker can withstand harsh environmental conditions and consume low power, but the low frequency response is poor (below 300 Hz)

Engineering Contradiction:

Improveenvironmental withstand capabilityVSAvoidlow frequency response

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The sound generation system is segmented into two independent paths: an exterior speaker for high-frequency sounds and an interior speaker for low-frequency sounds. This segmentation allows each speaker to be optimized for its specific frequency range and environmental requirements, resolving the contradiction between environmental durability and low-frequency performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system transitions from a single-dimension (exterior only) approach to a two-dimension approach by utilizing both interior and exterior speakers. The interior speaker operates in the protected cabin environment to generate low frequencies, while the exterior speaker handles high frequencies in the harsh external environment, effectively adding a spatial dimension to the sound generation system.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of operation

If an exterior speaker is used for VSG output, then the sound is audible to pedestrians, but the deep low frequency sounds are attenuated by the vehicle chassis

Engineering Contradiction:

Improvepedestrian audibilityVSAvoidlow frequency sound quality

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The interior speaker acts as an intermediary for low-frequency sound generation. It produces deep bass sounds inside the vehicle cabin where the sound is not attenuated by the chassis, and these sounds naturally transmit through the vehicle structure to supplement the exterior speaker output, thereby enhancing overall sound quality without compromising pedestrian audibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If conventional VSG speakers are used, then the system is compact and weatherproof, but it cannot replicate deep pitch sounds of high-performance engines

Engineering Contradiction:

Improvesystem compactnessVSAvoiddeep pitch sound replication

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The interior speaker system is utilized for dual purposes: its original function for in-cabin audio and the additional function of generating low-frequency engine sounds. This multi-functionality approach allows the system to achieve deep pitch sound replication without adding dedicated hardware, maintaining system compactness while enhancing sound quality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution provides an improved frequency response that accurately mimics high-performance combustion engines, enhancing both safety and the driving experience by making deep sounds audible outside the vehicle without additional hardware, while maintaining low power consumption and weatherproofing.

Implementation Method 1

software algorithms for multitrack mixing, pitch shifting and amplitude scaling in relation to vehicle speed

Methodology Applied

Scientific EffectPitch shifting:

Implementation Method 2

software algorithms for multitrack mixing, pitch shifting and amplitude scaling in relation to vehicle speed

Methodology Applied

Scientific EffectAmplitude scaling:

Implementation Method 3

the vehicle sound module includes a frequency filter for filtering simulated vehicle sounds into the interior sound signal occupying a low frequency band and the exterior sound signal occupying a high frequency band

Methodology Applied

Scientific EffectFrequency filtering: Filter (electronic)

Implementation Method 4

an exterior speaker used in VSG systems... controlled by a VSG processor to generate externally audible sounds

Methodology Applied

Scientific EffectElectroacoustic transduction:

Data Source

PatentEP4329332A1Vehicle sound generator, method, and software

Publication Date: 2024.02.28 APTIV TECHNOLOGIES AG

Figure 1~3

AI summary

A vehicle sound generator, including a vehicle sound module (4) for generating vehicle sound signals. The vehicle sound signals are based on, at least in part, a vehicle status input, an exterior output for controlling an exterior speaker (2) and an interior output for controlling an interior speaker (3). The vehicle sound module (4) is configured to generate an interior sound signal for outputting through the interior output and an exterior sound signal for outputting through the exterior output. The interior sound signal occupies a lower frequency band than the exterior sound signal.