| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To simplify a constitution, and quickly respond so as to accurately measure a concentration of a urea aqueous solution suitable for cleaning NOx without degrading a fuel consumption in a vehicle. <P>SOLUTION: A urea concentration detector 20 has a light emitting element 30, and a light receiving element 34, interposes the urea aqueous solution between the light emitting element 30 and the light receiving element 34, and detects the concentration of the urea aqueous solution from a relationship between the previously-obtained quantity of a light received by the light receiving element 34 and the concentration of the urea aqueous solution as an ambient temperature is considered by a thermistor 38. The light emitting element 30 is formed so as to emit the light in at least one of a first wavelength band of 1,500-1,900 nm and a second wavelength band of 2,100-2,300 nm. A recess 41 for interposing the urea aqueous solution includes a light guiding member 43. The light guiding member 43 is configured so as to define an optical path length. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
