Vehicle Fan Speed Control Using Audibility and Sound Masking
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Solution Overview
Problem
Existing fan control systems do not consider human hearing perception when determining the rotation speed of cooling fans, leading to potential auditory noise issues.
Innovation Solution
A fan control device that analyzes environmental and fan sounds using frequency spectrum analysis to determine an upper limit for the fan's rotation speed, ensuring the fan sound is less likely to be perceived as auditory noise by adjusting the rotation speed based on audibility thresholds and masking effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan rotation speed is increased to improve cooling performance, then cooling efficiency is improved, but auditory noise perception increases
Solution Approach 1:
The patent changes the control parameter from simple rotation speed to a comprehensive audibility index that incorporates frequency spectrum analysis and human hearing characteristics. By evaluating the fan sound spectrum against environmental noise and applying psychoacoustic models, the system determines an optimal rotation speed that maintains cooling performance while minimizing perceived noise through parameter optimization rather than simple speed reduction
Solution Approach 2:
The patent replaces traditional mechanical noise control methods with signal processing and psychoacoustic analysis. Instead of purely mechanical adjustments, the system uses frequency spectrum analysis, audibility index calculation, and masking effect evaluation to intelligently control fan operation, substituting mechanical intuition with computational acoustics
2Object-affected harmful factors
If the fan rotation speed is decreased to reduce noise, then auditory noise perception is reduced, but cooling performance deteriorates
Solution Approach 1:
The patent implements dynamic rotation speed adjustment based on real-time environmental noise conditions and fan sound characteristics. Rather than using a fixed low speed setting, the system continuously monitors the audibility index and adjusts the rotation speed dynamically to maintain the minimum necessary cooling performance while keeping perceived noise below thresholds, allowing optimal performance under varying conditions
3Object-affected harmful factors
If frequency spectrum analysis and audibility index calculation are implemented, then noise perception is minimized, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary computational layer that processes fan sound signals and environmental noise data to generate an audibility index. This intermediary system acts as a mediator between the physical fan operation and human perception, using frequency spectrum analysis and psychoacoustic models to translate raw acoustic data into actionable control parameters that minimize perceived noise without requiring complex hardware modifications
Data Source
AI summary
A fan control device that controls a fan used for cooling a cooling target in a vehicle includes a processor. The processor acquires an environmental sound in the vehicle collected by a microphone provided in the vehicle, derives first analysis data by executing frequency analysis on the acquired environmental sound, acquires second analysis data obtained by executing frequency analysis on a fan sound that varies depending on a rotation speed of the fan and that is a sound generated during rotation of the fan, and determines an upper limit of the rotation speed of the fan based on the first analysis data and the second analysis data such that a first index of the environmental sound satisfies a predetermined first condition, the first index being an index related to audibility.