Patent ID: 8733153

Claim:
A system for determining a quality of a fluid in a tank, the system comprising: a transducer configured to generate a sound wave and to detect an echo of the sound wave, the transducer positioned near the bottom of the tank such that the sound wave travels toward a fixed object, the fixed object positioned a known distance away from the transducer; a temperature sensor configured to detect a temperature of the fluid; and a controller configured to produce a signal to drive the transducer to produce the sound wave, receive an indication of the detected echo from the transducer, receive an indication of the temperature of the fluid from the temperature sensor, and determine whether a contaminant exists in the fluid based on the temperature of the fluid, a time period from when the sound wave is produced to when the echo is detected, and at least one of the group of a) whether a measured volume is out of range and b) a dilution of the fluid is detected while the measured volume of the fluid decreases.