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Journal of Scientific and Industrial Research (JSIR) >
JSIR Vol.68 [2009] >
JSIR Vol.68(01) [January 2009] >
| Title: | Spontaneous and highly accurate ultrasonic temperature measurement system for air conditioner in automobiles |
| Authors: | Zhan, Tung-Sheng
Wu, Sun-Li
Tsai, Wen-Yuan |
| Keywords: | Continuous wave
Microprocessor
Multi-frequency
Phase detector
Ultrasonic measurement |
| Issue Date: | Jan-2009 |
| Publisher: | CSIR |
| Abstract: | This paper presents a microprocessor-based, ultrasonic air temperature sensor system whose output controls temperature
adjustment of car air conditioner (AC). Perceived thermal comfort correlates better with temperature of bulk air than temperature
measured by conventional in-car temperature sensor. It uses ultrasonic measurement of changes in sound speed in air to
determine temperature of bulk air. Changes in sound speed are calculated from phase shift of multi-frequency continuous
wave. A 89c51 single-chip microprocessor-based signal generator and phase detector was used to record and calculate phase
shift and temperature. Advantages of proposed system are high accuracy, instant detection, wider range and low cost. |
| Page(s): | 44-51 |
| ISSN: | 0022-4456 |
| Source: | JSIR Vol.68(01) [January 2009]
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