Granted Patent B2

US 8,303,463 · App. 12/250,514 · Granted Nov 6, 2012

Abstract

Claims (41)

1. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member via selective application of a plurality of hydraulically-applied torque transfer clutches, said method comprising:

applying through a series of clutch fill events a series of incrementally changing command pressures in a pressure control solenoid controllably connected to one of said clutches, each successive applied command pressure having a lower pressure than an immediately preceding applied command pressure and each command pressure is directed to a command pressure line feeding a command pressure volume to achieve a full feed state within the pressure control solenoid allowing full exposure of a main pressure line to said clutch being filled;

monitoring a pressure switch fluidly connected to said pressure control solenoid and configured to indicate when said pressure switch is in the full feed state;

determining changes in cycle times of said pressure switch, each cycle time measuring a time between an initiation and an end of the full feed state for each of the incrementally changed command pressures;

selecting a preferred command pressure to achieve a touching state in said clutch based upon said changes in pressure switch cycle times; and

controlling said clutch based upon said preferred command pressure.

2. The method of claim 1 , wherein applying through said series of clutch fill events said series of incrementally changing command pressures comprises:

applying a series of incrementally decreasing command pressures.

3. The method of claim 1 , wherein selecting said preferred command pressure based upon said changes in pressure switch cycle times comprises:

selecting a lowest of said command pressures conforming with a subset of shortest of said changes in cycle times of said pressure switch.

4. The method of claim 1 , wherein selecting said preferred command pressure based upon said changes in pressure switch cycle times comprises:

identifying a first of said command pressures to create an overlap state to correspond to a change in cycle times of said pressure switch not conforming with a subset of shortest of said changes in cycle times of said pressure switch; and

selecting as said preferred command pressure a value equaling the sum of said identified first of said command pressures and a command pressure adjustment.

5. The method of claim 4 , wherein said command pressure adjustment equals one and a half times said incremental change utilized in said series of incrementally changing command pressures.

6. The method of claim 1 , further comprising:

monitoring said controlling said clutch based upon said preferred command pressure; and

if said monitoring said controlling ceases to validate said preferred command pressure, selecting a new preferred command pressure.

7. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member via selective application of a plurality of hydraulically-applied torque transfer clutches, said method comprising:

selecting a preferred command pressure in a pressure control solenoid fluidly connected to one of said clutches, said selecting comprising

iteratively filling said clutch with a calibration command pressure, wherein each successive iteration of said calibration command pressure has a lower pressure than an immediately preceding iteration of said calibration command pressure and said calibration command pressure is directed to a command pressure line feeding a command pressure volume to achieve a full feed state within the pressure control solenoid allowing full exposure of a main pressure line to said clutch being filled,

monitoring pressure switch cycle times for a pressure switch fluidly connected to said pressure control solenoid and configured to generate an indication when said pressure control solenoid is in the full feed state, each cycle time measuring a time between an initiation and an end of the full feed state, and

selecting from said calibration command pressures said preferred command pressure based upon identifying a transition between differences in said calibration command pressures, said transition corresponding to a touching state in said clutch; and

utilizing said preferred command pressure in subsequent operation of said clutch.

8. The method of claim 7 , further comprising:

comparing pressure switch cycles times during said subsequent operation of said clutch to expected cycle times; and

reselecting said preferred command pressure based upon said comparing.

9. An apparatus for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member via selective application of a plurality of hydraulically-applied torque transfer clutches, said method comprising:

a pressure control solenoid fluidly connected to one of said clutches;

a pressure switch fluidly connected to said pressure control solenoid monitoring when said pressure control solenoid is in a full feed state;

a pressure control solenoid control module, including programming to

apply through a series of clutch fill events a series of incrementally changing command pressures in said pressure control solenoid to create an overlap state in said pressure control solenoid, each successive applied command pressure having a lower pressure than an immediately preceding applied command pressure and each command pressure is directed to a command pressure line feeding a command pressure volume to achieve the full feed state within the pressure control solenoid allowing full exposure of a main pressure line to said clutch being filled,

monitor said pressure switch,

determine changes in cycle times of said pressure switch, each cycle time measuring a time between an initiation and an end of the full feed state for each of the incrementally changed command pressures,

select a preferred command pressure based upon a transition in said changes in pressure switch cycle times, said transition corresponding to a touching state in said clutch, and

control said clutch based upon said preferred command pressure.

10. The apparatus of claim 9 , wherein said series of incrementally changing command pressures comprises a series of incrementally decreasing command pressures.

11. The apparatus of claim 10 , wherein said programming to select said preferred command pressure based upon said changes in pressure switch cycle times comprises:

selection of a lowest of said command pressures conforming with a subset of shortest of said changes in cycle times of said pressure switch.

12. The apparatus of claim 9 , wherein said programming further comprises:

validation of said preferred command pressure through subsequent operation of said clutch; and

reselection of said preferred command pressure based upon a failure in said validation.

Assignments (17)