Methods and system for applying a driveline disconnect clutch

A driveline system, comprising:

• an engine;
• a driveline integrated starter/generator (DISG);
• a driveline disconnect clutch selectively coupling the engine and the DISG;
• and
• a controller including executable instructions stored in non-transitory memory for:
• in response to an engine start request,
• determining a start of a closing pressure based on a determined engine cranking torque, an engine stopping position, barometric pressure, engine coolant temperature, and a rate of change in an accelerator pedal position;
• determining a pressure ramp rate based on the rate of change in the accelerator pedal position and available DISG torque, where said determined start of closing pressure is increased for one or more of an increase in rate of change in the accelerator pedal position, a decrease in the engine coolant temperature, and an increase in the barometric pressure, the available DISG torque being a maximum DISG torque at a present DISG speed and a present temperature minus a present DISG output torque;
• and
• adjusting a pressure of a working fluid supplied to the driveline disconnect clutch from the determined start of closing pressure at the determined pressure ramp rate.