| 摘要 |
PROBLEM TO BE SOLVED: To provide a concentration sensor device capable of estimating the concentration of a component other than a main component in a mixture. SOLUTION: A sensor part 10 selects one of two different kinds of frequencies wherein each dielectric constant of gasoline and ethanol is approximately the same and a dielectric constant of water is changed from, for example, frequency bands higher than 50 [kHz] and lower than 500 [kHz], and the other from, for example, frequency bands higher than 500 [kHz] and lower than 10 [MHz], and applies an AC voltage to a first electrode 12a and a second electrode 12b constituting an interdigital electrode with each selected frequency. A concentration estimation part calculates/estimates the concentration of water based on a difference between each dielectric constant detected by application of the AC voltage to the first electrode 12a and the second electrode 12b with each frequency. Further, the concentration estimation part regards a mixed fuel as being constituted of only gasoline and ethanol, and calculates/estimates the concentration of gasoline and the concentration of ethanol by using the estimated concentration of water. COPYRIGHT: (C)2009,JPO&INPIT
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