Engine Sound Harmonic Control for Natural Cabin Acoustics

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Solution Overview

Problem

Existing sound enhancement systems for vehicle engines fail to accurately replicate natural engine harmonics, leading to an unnatural sonic experience in vehicle cabins, especially in quiet vehicles or during transitions between internal combustion and electric power in hybrid vehicles.

Innovation Solution

An active sound management system comprising a transducer, harmonic extractor, and harmonic modifier that senses actual engine sounds, extracts harmonics, and adjusts their magnitude, phase, and frequency to match predefined targets, using RPM data and engine load measurements to generate a natural engine sound experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing sound enhancement systems are used to generate engine harmonics, then some sound output is produced, but the harmonics are unnatural and fail to accurately replicate real engine sound

Engineering Contradiction:

Improveaccuracy of harmonic replicationVSAvoidnaturalness of sonic experience

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system uses a feedback mechanism where the actual engine sound is captured by a transducer, analyzed to extract real harmonic content, and then used to guide the synthesis process. The extracted harmonics from actual engine operation are compared with target harmonics, and the synthesis is adjusted accordingly to achieve accurate replication of natural engine sound characteristics.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system copies the actual harmonic structure of real engine sound by capturing the engine's acoustic output, analyzing its spectral content, and replicating these measured harmonics in the synthesized sound. This copying approach ensures that the generated harmonics faithfully represent the natural engine sound rather than relying on theoretical models.

Inventive Principle:

Principle #26Copying

2Ease of operation

If the engine sound is enhanced to be more stimulating, then driver engagement improves, but the sound may become overly loud and unnatural

Engineering Contradiction:

Improvedriver engagementVSAvoidexcessive loudness

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the harmonic enhancement levels based on actual engine operating conditions. By continuously analyzing the engine's real-time sound output and adapting the synthesis parameters accordingly, the system provides stimulating sound enhancement that remains proportional to actual engine activity, preventing excessive loudness while maintaining driver engagement.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes acoustic parameters such as harmonic magnitude, frequency distribution, and spectral balance based on measured engine characteristics. By adjusting these parameters dynamically rather than using fixed enhancement levels, the system achieves stimulating sound output that adapts to engine conditions and avoids becoming overly loud or unnatural.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If harmonics are extracted and adjusted to match target values, then sound accuracy improves, but the system complexity increases

Engineering Contradiction:

Improveharmonic accuracyVSAvoidsystem structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses a multi-functional architecture where the transducer serves both as a sound capture device and a reference for harmonic extraction. The same processing chain is used for both analyzing actual engine sound and synthesizing enhanced sound, reducing the need for separate dedicated components and simplifying the overall system structure while maintaining high harmonic accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system is self-calibrating by using its own captured engine sound as the reference for harmonic extraction and synthesis. The transducer captures actual engine harmonics, which then serve as the basis for generating target harmonics and guiding the enhancement process, eliminating the need for external calibration equipment or pre-programmed engine characteristics.

Inventive Principle:

Principle #25Self-service

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 system effectively enhances the engine sound experience in vehicle cabins by replicating natural harmonics, providing a consistent and stimulating sound without being overly loud, even in quiet vehicles or during power transitions, thereby improving driver engagement and sensory feedback.

Implementation Method 1

a transducer that senses an actual sound or vibration from a sound generating source and generates a transducer signal in response to sensing the actual sound or vibration

Methodology Applied

Scientific EffectTransduction:

Data Source

PatentUS10020788B2Vehicle engine sound management

Publication Date: 2018.07.10 BOSE CORP

AI summary

An active sound management system comprises a transducer that senses an actual sound or vibration from a sound generating source and generates a transducer signal in response to sensing the actual sound or vibration; a harmonic extractor device that extracts a plurality of harmonics from the transducer signal; and a harmonic modifier device that adjusts a feature of the extracted harmonic to be within a predetermined threshold with respect to a target harmonic corresponding to a desired sound.