Vehicle Approach Alert Device Temperature Compensation
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Solution Overview
Problem
Existing vehicle approach alert devices face issues with sound pressure output variations due to temperature changes, leading to frequency gaps and undesirable audible sound levels, as they rely on additional temperature sensors and simple voltage adjustments, which increase component count and do not accurately account for the temperature's effect on the speaker's frequency characteristic.
Innovation Solution
A vehicle approach alert device that estimates the temperature of the sounding body using temperature sensors located elsewhere in the vehicle, calculates the temperature based on external and internal component temperatures, and adjusts the sound pressure and frequency output accordingly without adding a dedicated temperature sensor for the sounding body, using a microcontroller to generate and correct the voltage waveform signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is attached near or inside the speaker to detect the speaker temperature, then the sound pressure correction becomes more accurate, but the number of components increases
Solution Approach 1:
The patent uses an intermediary approach by detecting the temperature of components surrounding the speaker (such as the housing or mounting structure) instead of directly measuring the speaker temperature. This intermediary temperature measurement provides sufficient information for sound pressure correction without requiring direct contact with the speaker, thus avoiding additional components while maintaining adequate measurement accuracy for the correction purpose.
Solution Approach 2:
The patent creates a thermal model that copies or simulates the speaker temperature based on measurements from other components in the audio system. By establishing a relationship between the temperatures of surrounding components and the speaker temperature, the system can estimate the speaker temperature without direct measurement, thereby avoiding additional temperature sensors while achieving accurate correction.
2Device complexity
If only the resistance change of the voice coil is considered for sound pressure correction, then the correction process becomes simpler, but the frequency characteristic and audible sound level become inaccurate
Solution Approach 1:
The patent applies parameter changes by adjusting multiple parameters of the audio signal including gain (amplitude), frequency, and timing based on the detected temperature. Instead of only compensating for resistance changes, the system modifies multiple signal parameters to comprehensively address temperature effects on both sound pressure and frequency characteristics, ensuring accurate audio reproduction across varying temperature conditions.
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 reduces sound pressure variations and maintains a consistent audible sound level by accurately accounting for temperature changes, ensuring the sound pressure and frequency output remain within desired limits without the need for additional temperature sensors, thus enhancing the reliability of the vehicle approach alert system.
Implementation Method 1
acquire information about a temperature detected by a temperature sensor located at a position different from the sounding body in the vehicle
Data Source
Figure 1
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Figure 4
AI summary
A vehicle approach alert device that outputs an approach report sound from a sounding body (3) includes: a memory part (21 a) in which data of the approach report sound is memorized; a signal generator (21 b) that generates a voltage waveform signal of the approach report sound based on the data of the approach report sound; a calculator (21 d) that calculates a temperature of the sounding body (3); and a correct part (21 e) that corrects the approach report sound based on the temperature of the sounding body. The calculator (21d) acquires information about a temperature detected by a temperature sensor (1b, 1c) located at a position different from the sounding body (3) in the vehicle, and estimates the temperature of the sounding body based on the temperature detected by the temperature sensor.