Active Exhaust Sound Generation via Signal Segmentation
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Solution Overview
Problem
Current active sound systems for vehicles with internal combustion engines or hybrid drive systems struggle to produce a natural-sounding exhaust sound due to technical limitations in frequency range, resulting in synthetic-sounding exhaust noise that is undesirable for safety and driver experience.
Innovation Solution
A sound generator system with an electroacoustical transducer and control unit that selectively amplifies specific segments of the audio signal to create a high harmonic content, mimicking the natural acoustic pattern of conventional exhaust systems, by multiplying signal values and limiting them to a maximum amplitude, allowing for continuous transitions and generating higher frequency harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If software processing device generates control signal limited to around 500 Hz, then device complexity is reduced, but the exhaust sound appears synthetic and unnatural
Solution Approach 1:
The audio signal is divided into multiple segments along the time axis, and different amplification factors are applied to different segments. This segmentation allows the system to generate higher frequency harmonics in specific time portions while keeping the overall processing manageable, thus improving sound naturalness without proportionally increasing device complexity.
Solution Approach 2:
The amplification factor is made dynamic and time-dependent, varying across different segments of the audio signal. This dynamic approach enables the system to adaptively generate higher frequency content where needed while maintaining lower frequency content elsewhere, achieving more natural exhaust sound without requiring a completely complex processing system.
2Object-generated harmful factors
If complete elimination of exhaust sounds is achieved, then sound-absorbing devices performance is improved, but safety risk increases and driver experience deteriorates
Solution Approach 1:
Instead of uniformly eliminating all exhaust sounds, the system applies selective amplification to specific segments of the audio signal. This creates local variations in sound quality, enhancing certain frequency ranges and time portions while maintaining overall sound reduction, thus preserving safety cues and driver experience while achieving noise reduction goals.
Solution Approach 2:
The system changes the parameters of the exhaust sound by selectively amplifying specific frequency ranges and time segments. This parameter modification allows the sound to be transformed from a completely eliminated state to a controlled state where harmful emissions are reduced but essential auditory information for safety and driver confidence is preserved.
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 produces a natural-sounding exhaust sound that is characteristic of the vehicle's drive system conditions, enhancing safety and driver confidence by providing a more authentic auditory experience.
Implementation Method 1
an electroacoustical transducer (11) which is configured to produce an acoustical signal in dependence on an electrical input signal
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention concerns a sound generator system for a vehicle with internal combustion engine (15) and/or electric motor, wherein the sound generator system (1, 70) has an electroacoustical transducer (11) and a control unit (24, 74). The electroacoustical transducer (11) is configured to produce an acoustical signal in dependence on an electrical input signal and is connected to an acoustic line (7) configured for transmission of the sound to the surroundings of the vehicle and/or into an exhaust line (9) of the vehicle. The control unit (24, 74) is configured to create a primary audio signal with frequencies from a given frequency range, to selectively amplify selected segments ("V") of the primary audio signal so that the audio signal (41) amplified in the selected segments has at least one section in which all audio signal values correspond to a maximum amplitude value that is specified for the segment, and the audio signal (41) amplified in the selected segments is continuous at the transitions from the at least one section to its neighboring sections, and wherein the audio signal (41) generated by the control unit (24) forms the basis of the electrical input signal.