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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
Appears in Collections:JSIR Vol.68(01) [January 2009]

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