Engine Sound Enhancement Using Casing Vibration Detection
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Solution Overview
Problem
Existing engine sound enhancement systems fail to accurately reproduce the real engine sound, relying on artificial signals and multiple microphones, which are costly and cumbersome.
Innovation Solution
A vibration sensor mounted on the engine casing detects vibrations to generate a signal indicative of the engine sound, processed by a signal processor and amplified by a speaker to enhance the sound within the vehicle compartment, eliminating the need for artificial synthesizing and multiple microphones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sound pressure sensor is disposed in the intake tract or exhaust tract to detect sound pressure, then the system can generate an audio signal, but it cannot accurately detect the real motor sound because it only considers sound propagating in the tract without considering vibration of the motor casing
Solution Approach 1:
The patent combines the sound pressure sensor (microphone) and vibration sensor (accelerometer) into a single integrated sensing system. The sound pressure sensor captures acoustic information from the intake or exhaust tract, while the vibration sensor simultaneously detects mechanical vibrations of the engine casing. These two different types of information are merged and processed together to reconstruct a more complete and accurate representation of the real engine sound, overcoming the limitation of using either sensor alone.
Solution Approach 2:
The patent introduces a signal processing unit that acts as an intermediary between the raw sensor data and the final synthesized engine sound. This unit receives signals from both the sound pressure sensor and vibration sensor, processes them through algorithms that account for the acoustic characteristics of the vehicle compartment, and synthesizes them into a realistic engine sound reproduction. The signal processing unit mediates the transformation of physical measurements into perceptual audio output.
2Ease of operation
If a synthesizer is used to generate a completely artificial synthesized signal and add it to the sound pressure sensor signal, then the system can enhance engine sound, but the artificial sound can never be identical to the real motor sound
Solution Approach 1:
The patent replaces the purely artificial signal synthesis approach with a hybrid system that incorporates actual physical measurements. Instead of generating completely synthetic engine sounds through algorithms alone, the system uses a vibration sensor to directly measure the mechanical vibrations of the engine casing and converts these physical measurements into audio signals. This substitution of mechanical measurement for artificial generation significantly improves the fidelity and realism of the reproduced engine sound.
Solution Approach 2:
The patent segments the engine sound reproduction task into distinct components handled by different sensors and processing paths. The sound pressure sensor handles the acoustic pressure field information, while the vibration sensor handles the structural vibration information. Each sensor type processes its specific domain of information separately, and then the results are combined. This segmentation allows each component to be optimized for its specific function while maintaining overall system accuracy.
3Adaptability or versatility
If multiple microphones are disposed in various parts of the vehicle to detect driving conditions, then the system can control gain of signals, but the system becomes expensive, complicated and cumbersome
Solution Approach 1:
The patent makes the vibration sensor serve multiple functions simultaneously. It not only detects engine casing vibrations for sound reproduction but also provides information about engine operating conditions, load, and speed. The single vibration sensor replaces what would otherwise require multiple microphones positioned at different locations to detect the same types of information. This multi-functionality reduces the total number of sensors needed while maintaining or enhancing the system's adaptability to different driving conditions.
Solution Approach 2:
The vibration sensor inherently provides information about engine operating conditions as a byproduct of its primary function of detecting engine vibrations. The same sensor that measures casing vibrations for sound reproduction also captures data about engine speed, load, and operational state. This self-service capability eliminates the need for separate sensors dedicated to monitoring driving conditions, simplifying the overall system while maintaining versatility in adapting to different operating scenarios.
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 provides an accurate and efficient engine sound enhancement that closely mimics the real engine sound, reducing costs and complexity while improving driver experience.
Implementation Method 1
a vibration sensor disposed on the engine casing to detect the vibrations of the engine casing and generate a signal indicative of the engine sound
Implementation Method 2
a speaker disposed in the vehicle compartment and connected to said signal processor to receive said output audio signal and generate a sound to enhance the engine sound
Data Source
AI summary
A sound enhancement system of an engine of a vehicle includes a vibration sensor disposed on the casing of the engine to generate an electrical signal indicative of the engine sound. A signal processor is connected to the vibration sensor to process the electrical signal-indicative of the engine sound and generate an output audio signal. A speaker is disposed in the vehicle compartment and connected to the signal processor to receive the output audio signal and generate an enhancement sound of the engine sound.