Systems and methods for controlling friction elements

A hybrid vehicle comprising:

• an engine;
• an electric machine;
• a disconnect clutch configured to selectively couple the engine to the electric machine;
• and
• a controller configured to execute control loop cycles at a predetermined cycle time such that each of the control loop cycles has a duration equal to the cycle time, the controller being programmed to
• responsive to a request to engage the disconnect clutch, sequentially command, during a boost phase of clutch engagement, a first hydraulic boost pressure to the disconnect clutch for a first duration of time equal to a plurality of the control loop cycles and a second hydraulic boost pressure to the disconnect clutch for a second duration of time including only one of the control loop cycles such that the second duration of time is equal to the cycle time, wherein the second hydraulic boost pressure is less than the first hydraulic boost pressure, and
• responsive to the end of the boost phase, command a hysteresis pressure to the disconnect clutch.