System and method for calibrating transmission
A method and system for automatically estimating clutch control parameters is described. In one example, a torque source is operated in a speed control mode so that changes in torque source torque output may be indicative of torque transfer through a clutch. Torque source torque output values may be a basis for estimating clutch fill time and clutch touch pressure.
1 . A method for determining a clutch fill time, comprising:
adjusting a valve to flow a fluid to a clutch; and
adjusting the clutch fill time based on an amount of time between adjusting the valve and a torque output of an electric machine increasing by more than a threshold amount of torque to maintain speed of the electric machine.
2 . The method of claim 1 , further comprising operating the electric machine in a speed control mode while the torque output of the electric machine is variable.
3 . The method of claim 2 , further comprising adjusting the valve when a transmission that includes the clutch is engaged in park or neutral.
4 . The method of claim 1 , further comprising adjusting a clutch touch pressure in response to the torque output of the electric machine.
5 . The method of claim 4 , where the clutch touch pressure is adjusted in response to the torque output of the electric machine being less than a minimum clutch touch pressure.
6 . The method of claim 4 , where the clutch touch pressure is adjusted in response to the torque output of the electric machine being greater than a maximum clutch touch pressure.
7 . The method of claim 4 , where the clutch touch pressure is a clutch pressure at which torque capacity of the clutch begins to increase from zero.
8 . The method of claim 1 , further comprising operating the electric machine in a speed control mode prior to and during adjusting the valve to flow the fluid to the clutch.
9 . A vehicle system, comprising:
one or more torque sources;
a transmission including a plurality of clutches and gears;
a controller including executable instructions that cause the controller to operate one of the one or more torque sources in a speed control mode and perform an automatic clutch parameter determination sequence that generates a clutch fill time and a clutch touch pressure according to output torque of one of the one or more torque sources.
10 . The vehicle system of claim 9 , further comprising additional instructions that cause the controller to increase a pressure in one of the plurality of clutches to a fill pressure while operating the one of the one or more torque sources in the speed control mode.
11 . The vehicle system of claim 10 , further comprising additional instructions that cause the controller to decrease the pressure in one of the plurality of clutches such that torque output of the one of the one or more torque sources is greater than a drag torque and less than a touch torque.
12 . The vehicle system of claim 11 , further comprising additional instructions that cause the controller to:
decrease the pressure in one of the plurality of clutches to substantially zero pressure for a predetermined amount of time since the pressure in the one of the plurality of clutches caused torque output of the one or more torque sources to be greater than the drag torque and less than the touch torque.
13 . The vehicle system of claim 9 , further comprising additional instructions that cause the controller to increase a pressure in one of the plurality of clutches to a fill pressure while operating the one of the one or more torque sources in the speed control mode and increase an amount of time the fill pressure is applied to the one of the plurality of clutches in response to electric machine torque being less than a touch torque.
14 . The vehicle system of claim 9 , further comprising additional instructions that cause the controller to increase a pressure in one of the plurality of clutches to a fill pressure while operating the one of the one or more torque sources in the speed control mode and decrease an amount of time the fill pressure is applied to the one of the plurality of clutches in response to electric machine torque being greater than a touch torque.
15 . The vehicle system of claim 9 , further comprising additional instructions that cause the controller to increase or decrease a pressure in one of the plurality of clutches after reducing the pressure in the one of the plurality of clutches from a fill pressure during the automatic clutch parameter determination sequence in response to electric machine torque.
16 . A method for determining a clutch fill time, comprising:
operating a torque source in a speed control mode and monitoring a torque output of the torque source while the torque source is operating in the speed control mode;
increasing a clutch pressure from substantially zero pressure to a clutch fill pressure and maintaining the clutch pressure for an amount of time; and
adjusting the amount of time according to the torque source torque output.
17 . The method of claim 16 , further comprising decreasing the clutch pressure from the clutch fill pressure to a clutch touch pressure.
18 . The method of claim 17 , further comprising adjusting the clutch touch pressure according to the torque source torque output.
19 . The method of claim 16 , where adjusting the amount of time includes increasing the amount of time in response to the torque source torque output being less than a threshold torque.
20 . The method of claim 16 , where adjusting the amount of time includes decreasing the amount of time in response to the torque source torque output being greater than a threshold torque.