Sensing characteristics and a type of fluid using a temperature dependent rate of change of a measurement of the fluid

1. A system for sensing characteristics of a fluid contained within a tank, the system comprising:

an ultrasonic sensor configured to

output a ultrasonic pulse into the fluid contained with the tank,

receive an echo of the ultrasonic pulse, and

output a signal based on the received echo;

a temperature sensor configured to sense a temperature of the fluid contained within the tank and output a temperature signal corresponding to the temperature of the fluid contained within the tank; and

a controller configured to determine whether the fluid in the tank has changed, and upon determining the fluid has changed:

determine a time-of-flight based on the output of the ultrasonic pulse and the received echo of the ultrasonic pulse,

receive the temperature signal,

determine an index corresponding to a characteristic of the fluid contained within the tank based on the time-of-flight and the temperature signal,

compare a slope of the index to a baseline slope of a baseline index, and

output a signal based on the comparison between the slope of the index and the baseline slope of the baseline index.

2. The system of claim 1 , wherein the baseline index corresponds to at least one baseline characteristic selected from a group consisting of a viscosity, a grade, a brand, and a quality, of a known fluid.

3. The system of claim 1 , wherein the controller determines whether the fluid has been changed based on comparing a level to a previously-determined level.

4. The system of claim 1 , wherein the controller determines whether the fluid has been changed based on receiving a fluid change signal.

5. The system of claim 1 , wherein the characteristic is at least one characteristic selected from a group consisting of a grade, a brand, a kinematic viscosity, a quality, and a level.

6. The system of claim 1 , wherein the system is coupled to a bottom of the tank.

7. The system of claim 1 , further comprising an aeration filter.

8. The system of claim 7 , wherein the aeration filter includes a mesh.

9. A method of sensing a characteristic of a fluid contained within a sensing area of a tank, the method comprising:

determining whether the fluid in the tank has changed, and upon determining the fluid has changed:

outputting, via a transducer, an ultrasonic pulse through the fluid;

receiving, via the transducer, an echo of the ultrasonic pulse;

determining, via a controller, a time-of-flight of the ultrasonic pulse;

receiving, via a temperature sensor, a temperature of the fluid;

determining, via the controller, an index corresponding to a characteristic of the fluid based on the time-of-flight and the temperature;

comparing, via the controller, a slope of the index to a baseline slope of a baseline index; and

outputting, from the controller, a signal based on the comparison between the slope of the index and the baseline slope of the baseline index.

10. The method of claim 9 , wherein the baseline index corresponds to at least one baseline characteristic selected from a group consisting of a viscosity, a grade, a brand, and a quality, of a known fluid.

11. The method of claim 9 , wherein the step of determining whether the fluid has been changed is based on comparing a level to a previously-determined level.

12. The method of claim 9 , wherein the step of determining whether the fluid has been changed is based on receiving a fluid change signal.

13. The method of claim 9 , wherein the characteristic is at least one characteristic selected from a group consisting of a grade, a brand, a kinematic viscosity, a quality, and a level.