Methods and system for operating a vehicle transmission
Systems and methods for operating a transmission of a hybrid vehicle's driveline are presented. In one example, the systems and methods adjust operation of an electrically driven transmission pump that supplies transmission fluid to one or more transmission components in response to a rotational stopping position of a mechanically drive transmission pump.
1. A driveline operating method performed by an electronic controller, comprising:
determining, with the controller, a rotational stop position of a mechanically driven transmission pump; and
adjusting a speed of an electric transmission pump via the controller in response to the rotational stop position of the mechanically driven transmission pump in order to compensate for leakage of the mechanically driven transmission pump that varies with the rotational stop position to provide a desired transmission line pressure.
2. The method of claim 1 , where the rotational stop position is determined via a driveline integrated starter/generator position sensor.
3. The method of claim 1 , further comprising adjusting the rotational stop position in response to energy consumption of the electric transmission pump.
4. The method of claim 3 , where the rotational stop position is adjusted to a position where electric transmission pump energy consumption is determined to be a minimum value for providing the desired transmission line pressure, the desired transmission line pressure greater than a threshold via the electric transmission pump.
5. The method of claim 1 , where the desired transmission line pressure is a pressure sufficient to maintain an operating state of a transmission component.
6. The method of claim 5 , where the transmission component is a transmission clutch.
7. A driveline operating method performed by a controller, the controller performing:
sending signals to respective actuators to:
open a driveline disconnect clutch to couple an engine to a driveline integrated starter/generator;
stop rotation of the driveline integrated starter/generator to stop a mechanically driven transmission pump at a rotational stop position;
adjust a speed of an electric transmission pump in response to the rotational stop position of the mechanically driven transmission pump in order to compensate for leakage of the mechanically driven transmission pump that varies with the rotational stop position;
command the driveline disconnect clutch closed to equalize a pressure of fluid supplied to the driveline disconnect clutch and electrically driven transmission fluid pump outlet pressure; and
adjust the speed of the electric transmission pump in response to the pressure of fluid supplied to the driveline disconnect clutch to reach a desired transmission line pressure.
8. The method of claim 7 , where the driveline disconnect clutch is commanded closed for a time less than a time it takes to close the driveline disconnect clutch.
9. The method of claim 7 , where the pressure of fluid supplied to the driveline disconnect clutch is sampled between a control valve and the driveline disconnect clutch, and where the control valve is positioned along a conduit at a location between the driveline disconnect clutch and the electric transmission pump.
10. The method of claim 7 , further comprising adjusting the rotational stop position in response to energy consumption of the electric transmission pump.
11. The method of claim 7 , further comprising commanding the driveline disconnect clutch open after commanding the driveline disconnect clutch closed.
12. The method of claim 7 , where the driveline disconnect clutch is commanded closed via a solenoid.
13. The method of claim 7 , where adjusting the speed of the electric transmission pump includes decreasing the speed of the electric transmission pump in response to the pressure of fluid being greater than a threshold pressure.
14. The method of claim 13 , further comprising adjusting the threshold pressure in response to transmission operating conditions.
15. A system, comprising:
an engine;
a motor;
a disconnect clutch positioned in a driveline between the engine and the motor;
a transmission coupled to the motor, the transmission including an electrically driven pump and a mechanically driven pump; and
a controller including executable instructions stored in non-transitory memory for maintaining a desired transmission line pressure by adjusting a predetermined speed of the electrically driven pump in response to a rotational stop position of the mechanically driven pump, in order to compensate for leakage of the mechanically driven pump, the rotational stop position being a position at which the mechanically driven pump stops rotating.
16. The system of claim 15 , where adjusting the predetermined speed includes revising a value stored in memory, and further comprising additional instructions to, during a subsequent driveline rotational stop where the mechanically driven pump stops rotating at the rotational stop position, operate the electrically driven pump at the adjusted predetermined speed.
17. The system of claim 15 , further comprising additional instructions to command the disconnect clutch open and determine a pressure output of the electrically driven pump when the disconnect clutch is commanded open.
18. The system of claim 15 , further comprising additional instructions to adjust a position of the mechanically driven pump in response to power consumed via the electrically driven pump.
19. The system of claim 15 , further comprising additional instructions to adjust the predetermined speed of the electrically driven pump after output pressure of the electrically driven pump is substantially constant.