Abstract: A method for adjusting clutch fill command pressure for a transmission using a lubrication compensator model includes determining clutch fill line pressure and lubrication compensator model pressures, and adjusting the clutch fill command pressure to achieve the lubrication compensator model pressure based on the torque converter clutch status.

Abstract: A method for adjusting clutch fill command pressure for a transmission using a lubrication compensator model includes determining clutch fill line pressure and lubrication compensator model pressures, and adjusting the clutch fill command pressure to achieve the lubrication compensator model pressure based on the torque converter clutch status.

Abstract: Method to control a clutch device within a transmission selectively coupling an internal combustion engine to a driveline includes controlling slip of the clutch device in response to an engine autostart event. Controlling slip includes adjusting a commanded fill pressure to the clutch device to a first predetermined magnitude that exceeds a pressure threshold until the clutch device is filled, decreasing the commanded fill pressure from the first predetermined magnitude to a second predetermined magnitude below the pressure threshold, and adjusting the commanded fill pressure in accordance with a first ramping profile and in accordance with a subsequent second ramping profile when a transmission input speed achieves a desired first transmission input speed.

Abstract: A vehicle transmission includes a plurality of oncoming clutches that are hydraulically-actuated. A controller is operatively connected to the plurality of oncoming clutches. An algorithm stored on and executable by the controller causes the controller to determine if at least one predefined coast condition is met and identify the plurality of oncoming clutches configured to be engageable during a downshift event from an initial gear ratio to respective other gear ratios. The initial gear ratio is greater than each of the respective other gear ratios. The algorithm causes the controller to generate a first pressure command to at least partially pressurize a first one of the oncoming clutches to a first staging pressure (PS1) if the at least one predefined coast condition is met prior to the downshift event. The first staging pressure (PS1) is defined as a first return spring pressure (PR1) minus a first variable correction factor (CF1).

Abstract: A vehicle transmission includes a plurality of oncoming clutches that are hydraulically-actuated. A controller is operatively connected to the plurality of oncoming clutches. An algorithm stored on and executable by the controller causes the controller to determine if at least one predefined coast condition is met and identify the plurality of oncoming clutches configured to be engageable during a downshift event from an initial gear ratio to respective other gear ratios. The initial gear ratio is greater than each of the respective other gear ratios. The algorithm causes the controller to generate a first pressure command to at least partially pressurize a first one of the oncoming clutches to a first staging pressure (PS1) if the at least one predefined coast condition is met prior to the downshift event. The first staging pressure (PS1) is defined as a first return spring pressure (PR1) minus a first variable correction factor (CF1).

Abstract: Method to control a clutch device within a transmission selectively coupling an internal combustion engine to a driveline includes controlling slip of the clutch device in response to an engine autostart event. Controlling slip includes adjusting a commanded fill pressure to the clutch device to a first predetermined magnitude that exceeds a pressure threshold until the clutch device is filled, decreasing the commanded fill pressure from the first predetermined magnitude to a second predetermined magnitude below the pressure threshold, and adjusting the commanded fill pressure in accordance with a first ramping profile and in accordance with a subsequent second ramping profile when a transmission input speed achieves a desired first transmission input speed.

Abstract: A method of preventing an automatic engine stop includes: determining a pressure difference between an accumulator fill volume and a fluid conduit in selective fluid communication with the accumulator fill volume; determining a change in the accumulator fill volume from the determined pressure difference; adding the change in the accumulator fill volume to a previous estimate of the accumulator fill volume to determine a current estimate of the accumulator fill volume; comparing the current estimate of the accumulator fill volume to a predetermined threshold; and preventing an automatic engine stop if the current estimate of the accumulator fill volume is below the predetermined threshold.

Abstract: A hydraulic control system and method for controlling a hydraulic system of a vehicle powertrain is provided, which includes an accumulator arranged to accumulate fluid when an engine is turned on, to retain fluid when the engine is turned off, and to discharge fluid to the transmission when the engine is restarted. The accumulator is actively filled through a controlled valve, and it may also be filled passively, for example, via ball check-valve. The method of controlling the hydraulic system includes providing a fluid line pressure to the transmission by opening a fluid passage when the engine is turned on; opening a valve to actively accumulate fluid from the fluid line pressure into an accumulator; closing the valve to retain the fluid in the accumulator; and discharging the fluid from the accumulator to the fluid passage when the engine is restarted.