METHOD AND APPARATUS TO CONTROL CLUTCH FILL PRESSURE IN AN ELECTRO-MECHANICAL TRANSMISSION

• US 20090111643A1
• Filed: 10/13/2008
• Published: 04/30/2009
• Est. Priority Date: 10/26/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: BMW AG (Bayerische Motoren Werke AG), Daimler AG (Mercedes-Benz Group AG), GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Chrysler LLC (Stellantis NV)
• Inventors: Sah, Jy-Jen F., Naqvi, Ali K.
• Granted Patent: US 8,303,463 B2
• Time in Patent Office: Days
• US Class Current: 477/5
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: F16D 2048/0221 Valves for clutch control systems; Details thereof
• CPC Class Codes: F16D 2500/3024 Pressure
• CPC Class Codes: F16D 2500/3166 Detection of an elapsed period of time
• CPC Class Codes: F16D 2500/50251 During operation
• CPC Class Codes: F16D 2500/50293 Reduction of vibrations
• CPC Class Codes: F16D 2500/70605 Adaptive correction; Modifying control system parameters, e.g. gains, constants, look-up tables
• CPC Class Codes: F16D 48/02 Control by fluid pressure
• CPC Class Codes: F16D 48/066 Control of fluid pressure, e.g. using an accumulator F16D48/062, F16D48/068 take precedence
• CPC Class Codes: F16H 2061/064 for calibration of pressure levels for friction members, e.g. by monitoring the speed change of transmission shafts
• CPC Class Codes: F16H 61/0206 Layout of electro-hydraulic control circuits, e.g. arrangement of valves for control of actuators selecting and moving final output members, e.g. shift forks F16H61/2807
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A method to control a powertrain including a transmission, an engine, and an electric machine includes applying through a series of clutch fill events a series of incrementally changing command pressures in a pressure control solenoid controllably connected to a clutch within the transmission, monitoring a pressure switch fluidly connected to the pressure control solenoid and configured to indicate when the pressure switch is in a full feed state, determining changes in cycle times of the pressure switch corresponding to sequential applications of the series of incrementally changing command pressures, selecting a preferred command pressure to achieve a transient state in the clutch based upon the changes in pressure switch cycle times, and controlling the clutch based upon the preferred command pressure.

Claims

8. 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 said calibration command pressure decreases with each iteration,

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 a 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; and

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

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;

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

determining changes in cycle times of said pressure switch corresponding to sequential applications of said series of incrementally changing command pressures;

selecting a preferred command pressure to achieve a transient 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. The method of claim 1, wherein selecting said preferred command pressure based upon said changes in said pressure switch cycle times comprises selecting said preferred command pressure based upon achieving a touching state in said clutch.

9. The method of claim 8, 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.

10. 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,

monitor said pressure switch,

determine changes in cycle times of said pressure switch corresponding to sequential applications of said series of incrementally changing command pressures,

select a preferred command pressure based upon said changes in pressure switch cycle times, and

control said clutch based upon said preferred command pressure.

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 to select said preferred command pressure based upon said changes in pressure switch cycle times is based upon determining achieving a touching state in said clutch.

13. 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.

10-1. The apparatus of claim 9, wherein said series of incrementally changing command pressures comprises a series of incrementally decreasing command pressures.