Device which measures oil level and dielectric strength with a capacitance based sensor using a ratiometric algorithm

摘要

A fluid level sensor and a method of operating the oil level sensor to measure the fluid level and dielectric strength of the fluid substantially simultaneously. The fluid level sensor having a compensator capacitor normally fully submerged within the fluid and a linear capacitor variably submerged as a function of fluid level. Oscillators convert the capacitance of the linear and compensator capacitors into a first and second frequency respectively. A processor uses the two frequencies and calibration data stored in a memory to calculate the fluid level and dielectric strength substantially simultaneously. The dielectric strength calculation may be based upon an offset from the second frequency from a known frequency of a known dielectric strength. The fluid level calculation may be based upon a ratio of a numerator to a denominator where the numerator is a difference between the second frequency and a second focal point frequency, and the denominator is a difference between the first frequency and a first focal point frequency.