TRANSMISSION OIL MEASUREMENT SYSTEM AND METHOD

• US 20090254256A1
• Filed: 01/09/2009
• Published: 10/08/2009
• Est. Priority Date: 03/31/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Olson, Bret M., Dlugoss, Randall B.
• Granted Patent: US 8,050,828 B2
• Time in Patent Office: Days
• US Class Current: 701/60
• CPC Class Codes: F16H 2059/683 Sensing pressure in control systems or in fluid controlled devices, e.g. by pressure sensors for hydrostatic transmissions F16H2059/6861
• CPC Class Codes: F16H 59/68 Inputs being a function of gearing status
• CPC Class Codes: F16H 59/72 dependent on oil characteristics, e.g. temperature, viscosity

Abstract

A system includes a pressure sensor that measures a transmission fluid pressure at a first fluid cavity of a transmission. A transmission control module receives the transmission fluid pressure, determines a transmission fluid temperature in the first fluid cavity based on the transmission fluid pressure, and controls the transmission fluid pressure based on the transmission fluid temperature.

Claims

1. A system comprising:

a pressure sensor that measures a transmission fluid pressure at a first fluid cavity of a transmission; and

a transmission control module that receives the transmission fluid pressure, that determines a transmission fluid temperature in the first fluid cavity based on the transmission fluid pressure, and that controls the transmission fluid pressure based on the transmission fluid temperature.

2. The system of claim 1 further comprising an application specific integrated circuit (ASIC) that includes the pressure sensor and a temperature sensor that measures a temperature of the ASIC.

3. The system of claim 2 wherein the wherein the transmission fluid temperature is further based on the temperature of the ASIC.

4. The system of claim 2 wherein the transmission fluid pressure includes a compensated transmission fluid pressure that is based on the temperature of the ASIC and an uncompensated fluid pressure that is not based on the temperature of the ASIC, and the transmission control module determines the transmission fluid temperature based on a difference between the compensated transmission fluid pressure and the uncompensated transmission fluid pressure.

5. The system of claim 4 wherein the ASIC transmits the transmission fluid pressure to the transmission control module and transmits data indicative of whether the transmission fluid pressure includes one of the compensated and uncompensated transmission fluid pressures.

6. The system of claim 1 wherein the transmission control module determines the transmission fluid temperature using at least one of a lookup table and a model.

7. The system of claim 1 wherein the transmission control module controls at least one of a solenoid and a valve based on the transmission fluid temperature.

8. The system of claim 1 wherein the pressure sensor is located in the first cavity.

9. The system of claim 1 wherein the transmission control module diagnoses a fault condition based on the transmission fluid temperature and a status of the transmission.

10. A method comprising:

measuring a transmission fluid pressure at a first fluid cavity of a transmission with a transmission sensor;

determining a transmission fluid temperature in the first fluid cavity based on the transmission fluid pressure; and

controlling the transmission fluid pressure based on the transmission fluid temperature.

11. The method of claim 10 further comprising providing an application specific integrated circuit (ASIC) that includes the pressure sensor and a temperature sensor that measures a temperature of the ASIC.

12. The method of claim 11 wherein the wherein the transmission fluid temperature is further based on the temperature of the ASIC.

13. The method of claim 11 wherein the transmission fluid pressure includes a compensated transmission fluid pressure that is based on the temperature of the ASIC and an uncompensated fluid pressure that is not based on the temperature of the ASIC, and further determining the transmission fluid temperature based on a difference between the compensated transmission fluid pressure and the uncompensated transmission fluid pressure.

14. The method of claim 13 wherein the ASIC transmits data indicative of whether the transmission fluid pressure includes one of the compensated and uncompensated transmission fluid pressures.

15. The method of claim 10 further comprising determining the transmission fluid temperature using at least one of a lookup table and a model.

16. The method of claim 10 further comprising controlling at least one of a solenoid and a valve based on the transmission fluid temperature.

17. The method of claim 10 wherein the pressure sensor is located in the first cavity.

18. The method of claim 10 further comprising diagnosing a fault condition based on the transmission fluid temperature and a status of the transmission.