| 摘要 |
PROBLEM TO BE SOLVED: To provide a liquid degradation detector and its method for accurately detecting the degree of degradation of a liquid even when a property of an element transmitting/receiving an ultrasonic wave is changed. SOLUTION: An ECU 23 is provided with a signal generating part 25 and a signal processing part 27. The signal processing part 27 is provided with a first peak hold circuit 27a holding a peak of a first received wave voltage V1 showing receiving intensity of a first reflection wave (first received wave) as the first reflection wave, a second peak hold circuit 27b holding a peak of a second received wave voltage V2 showing receiving intensity of a second reflection wave (second received wave) as the second reflection wave, and a microcomputer 27c. The microcomputer 27c inputs the peak holding values V1, V2 of the first and second received wave voltages and finds a ratio V2/V1 between both voltages V1, V2 so as to detect the degree of degradation of oil from the ratio V2/V1.
|
