Apparatus and technique for fluid level determination in automatic transmissions

A method for determining an oil level in a transmission driven by an engine, comprising:

• placing said transmission in neutral;
• determining an actual oil level within the transmission;
• determining a deviation of actual engine speed from a reference idle engine speed and compensating said determination of actual oil level as a function thereof;
• determining a period of time from when said transmission was placed in neutral and said determination of actual oil level was made and compensating said determination of actual oil level as a function thereof;
• calculating a deviation of said compensated oil level determination from a desired oil level and determining a volume error therefrom;
• determining a deviation of actual oil temperature from a typical operating reference temperature of the transmission oil;
• and
• adjusting said volume error as a function of said deviation of said oil temperature.

Apparatus for determining an oil level in a transmission driven by an engine, comprising:

• means within the transmission for generating a first signal corresponding to an actual transmission oil level and density;
• means within the transmission for generating a second signal corresponding to actual transmission oil temperature;
• and
• means connected to said transmission for receiving said first and second signals and determining said actual oil level as a function thereof, determining a deviation of actual engine speed from a reference idle engine speed, determining a period of time between when the transmission is placed in neutral and said determination of actual oil level is made, compensating said determination of actual oil level as a function of said deviation of engine speed and said period of time, calculating a deviation of said compensated oil level from a desired oil level and determining a volume error therefrom, determining a deviation of actual oil temperature from a typical operating reference temperature of the transmission oil, and adjusting said volume error as a function of said deviation of oil temperature.