End of fill detector for a hydraulic clutch

A method for detecting an end-of-fill condition of an actuator having a varying control volume, said end-of-fill condition corresponding to said varying control volume being pressurized to a predetermined end-of-fill pressure, said varying control volume being connected to a source of pressurized fluid by a control valve, said control valve being actuatable by a solenoid, said solenoid having a coil and an armature, comprising the steps of:

• energizing said coil with a first current;
• delivering a flow of fluid from said pressurized fluid to said actuator in response to the energization of said coil with said first current;
• detecting a flyback current in said coil, sensing noise in said flyback current;
• detecting a change in the level of noise in said flyback current;
• and responsively producing an end-of-fill signal in response to said change being greater than a predetermined threshold.

A method for engaging a hydraulic clutch having a varying control volume in response to an engage signal, said varying control volume being connected to a source of pressurized fluid by a control valve, said control valve being actuatable by a solenoid, said solenoid having a coil and an armature, comprising the steps of:

• energizing said coil with a first current;
• delivering a flow of fluid from said pressurized fluid to said clutch in response to the energization of said coil with said first current;
• detecting a flyback current in said coil, sensing noise in said flyback current;
• detecting a change in the level of noise in said flyback current;
• responsively producing an end-of-fill signal in response to said change being greater than a predetermined threshold;
• and
• receiving said end-of-fill signal and responsively energizing said coil with a second current.