System and method for estimating temperatures of a hydraulic fluid circulated by a hydraulic pump of a transmission

Patent metadata

Field	Value
Publication number	US-9921116-B2
Application number	US-201514678361-A
Country	US
Kind code	B2
Filing date	Apr 3, 2015
Priority date	Apr 3, 2015
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

A system including a current module, a second module, and a temperature module. The current module is configured to determine an amount of current drawn from a power source by a hydraulic pump of a transmission based on a current signal received from a current sensor. The current signal is indicative of the current drawn by the hydraulic pump. The second module is configured to determine (i) a speed of the hydraulic pump based on a speed signal received from a speed sensor, or (ii) an output torque of the hydraulic pump based on the amount of current drawn by the hydraulic pump. The speed signal is indicative of the speed of the hydraulic pump. The temperature module is configured to estimate a temperature of a hydraulic fluid circulated by the hydraulic pump based on (i) the amount of current drawn by the hydraulic pump, and (ii) the speed or the output torque of the hydraulic pump. The second module is configured to adjust the speed of the hydraulic pump based on the temperature of the hydraulic fluid.

First claim

What is claimed is:

1. A system comprising:
a current module configured to (i) determine a total amount of current drawn from a power source by a hydraulic pump of a transmission based on current signals received from respectively a first current sensor and a second current sensor, and (ii) generate a first output signal indicating the total amount of current, wherein the current signals are indicative of amounts of current drawn by a first phase and a second phase of the hydraulic pump, wherein the current module is configured to (i) determine an amount of current drawn from a third phase of the hydraulic pump based on the amounts of current indicated by the current signals, and (ii) determine the total amount of current based on the amounts of current drawn by the first phase, the second phase and the third phase of the hydraulic pump;
a second module configured to
receive the first output signal, and
determine (i) a speed of the hydraulic pump based on a speed signal received from a speed sensor, or (ii) an output torque of the hydraulic pump based on the total amount of current drawn by the hydraulic pump, wherein the speed signal is indicative of the speed of the hydraulic pump; and

a temperature module configured to
estimate a temperature of a hydraulic fluid circulated by the hydraulic pump based on (i) the amount of current drawn by the hydraulic pump, and (ii) the speed or the output torque of the hydraulic pump, and
generate a second output signal indicating the temperature of the hydraulic fluid,

wherein the second module is configured to (i) receive the second output signal, and (ii) adjust the speed of the hydraulic pump based on the temperature of the hydraulic fluid.

2. The system of claim 1 , comprising the first current sensor, the second current sensor and the speed sensor.

3. The system of claim 1 , further comprising a power inverter module configured to receive direct current from the power source and convert the direct current to an alternating current, wherein:
the hydraulic pump draws at least a portion of the alternating current; and
the total amount of current drawn by the hydraulic pump includes the at least a portion of the alternating current.

4. The system of claim 1 , wherein:
the second module is configured to determine the speed of the hydraulic pump based on the speed signal received from the speed sensor; and
the temperature module is configured to estimate the temperature of the hydraulic fluid based on the speed of the hydraulic pump.

5. The system of claim 1 , wherein:
the second module is configured to determine the output torque of the hydraulic pump based on the amount of current drawn by the hydraulic pump; and
the temperature module is configured to estimate the temperature of the hydraulic fluid based on the output torque of the hydraulic pump.

6. The system of claim 1 , wherein:
the temperature module is configured to select one of a plurality of temperature profiles based on the speed or the output torque of the hydraulic pump;
each of the plurality of temperature profiles provides for a respective speed or output torque of the hydraulic pump a current versus temperature relationship; and
the temperature module is configured to estimate the temperature of the hydraulic fluid based on the selected one of the plurality of temperature profiles.

7. The system of claim 1 , further comprising the hydraulic pump, wherein:
the second module is configured to generate a control signal based on the temperature of the hydraulic fluid; and
the hydraulic pump pumps the hydraulic fluid to friction coupling elements of the transmission based on the control signal.

8. A method comprising:
determining whether a fault has been diagnosed in a transmission control module;
in response to no fault being diagnosed in the transmission control module, triggering an auto-stop event of an engine;
determining a maximum line pressure of a hydraulic pump for the auto-stop event;
determining an amount of current drawn from a power source by the hydraulic pump of a transmission based on a current signal received from a current sensor, wherein the current signal is indicative of the current drawn by the hydraulic pump;
determining (i) a speed of the hydraulic pump based on a speed signal received from a speed sensor, or (ii) an output torque of the hydraulic pump based on the determined amount of current drawn by the hydraulic pump, wherein the speed signal is indicative of the speed of the hydraulic pump;
estimating a temperature of a hydraulic fluid circulated by the hydraulic pump based on (i) the determined amount of current drawn by the hydraulic pump, and (ii) the determined speed or the output torque of the hydraulic pump; and
adjusting a line pressure of the hydraulic pump to the maximum line pressure to increase load on the engine by the transmission including adjusting the speed of the hydraulic pump based on the estimated temperature of the hydraulic fluid.

9. The method of claim 8 , further comprising:
supplying direct current via the power source;
converting the direct current to an alternating current; and
drawing at least a portion of the alternating current via the hydraulic pump,
wherein the determined amount of current drawn by the hydraulic pump includes the at least a portion of the alternating current.

10. The method of claim 8 , further comprising:
receiving a 3-phase alternating current at the hydraulic pump;
detecting an amount of current supplied for a first phase of the hydraulic pump via the current sensor;
detecting an amount of current supplied for a second phase of the hydraulic pump via a third sensor; and
determining an amount of current supplied to a third phase of the hydraulic pump based on the determined amount of current supplied to the first phase and the determined amount of current supplied to the second phase,
wherein the determined amount of current drawn by the hydraulic pump includes the determined amount of current supplied for the first phase, the determined amount of current supplied for the second phase, and the determined amount of current supplied for the third phase.

11. The method of claim 10 , further comprising generating a second current signal, wherein:
the second current signal indicates the determined amount of current supplied for the first phase and the determined amount of current supplied for the second phase; and
the temperature of the hydraulic fluid is estimated based on the second current signal.

12. The method of claim 8 , wherein the determined amount of current drawn by the hydraulic pump is an amount of current drawn by a single phase of the hydraulic pump.

13. The method of claim 8 , wherein the determined amount of current drawn by the hydraulic pump is an amount of current drawn by at least two phases of the hydraulic pump.

14. The method of claim 8 , comprising:
determining the speed of the hydraulic pump based on the speed signal received from the speed sensor;
determining the output torque of the hydraulic pump based on the amount of current drawn by the hydraulic pump; and
estimating the temperature of the hydraulic fluid based on the speed of the hydraulic pump and the output torque of the hydraulic pump.

15. The method of claim 8 , further comprising selecting one of a plurality of temperature profiles based on the speed or the output torque of the hydraulic pump, wherein:
each of the plurality of temperature profiles provides for a respective speed or output torque of the hydraulic pump a current versus temperature relationship; and
the temperature of the hydraul

Assignees

• Gm Global Tech Operations Llc

Inventors

• Inan Mehmet Emin
• Adam Paul A

Classifications

• G01K2013/026

  Physics · mapped topic

• G01K7/427

  Temperature calculation based on spatial modeling, e.g. spatial inter- or extrapolation · CPC title

• F16H61/0204

  for gearshift control, e.g. control functions for performing shifting or generation of shift signal · CPC title

• G01R19/0092

  Measuring current only · CPC title

• G01L3/00 Primary

  Measuring torque, work, mechanical power, or mechanical efficiency, in general · CPC title