METHOD TO MANAGE A HIGH VOLTAGE SYSTEM IN A HYBRID POWERTRAIN SYSTEM

• US 20090118916A1
• Filed: 10/28/2008
• Published: 05/07/2009
• Est. Priority Date: 11/04/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Gleason, Sean Em, West, Stephen T., Cawthorne, William R., Tarchinski, James E., Kothari, Aniket, Kokotovich, Nicholas
• Granted Patent: US 8,214,120 B2
• Time in Patent Office: Days
• US Class Current: 701/53
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 28/14 responsive to accident or emergency, e.g. deceleration, tilt of vehicle
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60R 2021/0018 Roll-over
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/105 of electric type
• CPC Class Codes: B60W 10/115 with planetary gears
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2050/0006 Digital architecture hierarchy
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 2510/0638 : Engine speed
• CPC Class Codes: B60W 2510/0657 : Engine torque
• CPC Class Codes: B60W 2510/0671 : Engine manifold pressure
• CPC Class Codes: B60W 2510/0676 : Engine temperature
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2510/246 : Temperature
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2555/20 : Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 30/192 : Mitigating problems related to power-up or power-down of the driveline, e.g. start-up of a cold engine
• CPC Class Codes: B60W 50/035 : Bringing the control units into a predefined state, e.g. giving priority to particular actuators
• CPC Class Codes: F16H 2037/106 : with switching means to provide two variator modes or ranges
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

A powertrain includes an electromechanical transmission operative to transmit torque between an input member and an electric machine and an output member to transmit tractive torque. The electric machine is electrically connected to an inverter device which is electrically connected to an energy storage device. A method for operating the powertrain includes detecting a shutdown event, commanding the transmission to neutral, commanding the electric machine to cease operating in a torque generating mode, and electrically disconnecting the energy storage device from the inverter device.

Claims

1. A method for operating a powertrain comprising an electromechanical transmission operative to transmit torque between an input member and an electric machine and an output member to transmit tractive torque, the electric machine electrically connected to an inverter device electrically connected to an energy storage device, the method comprising:

detecting a shutdown event;

commanding the transmission to neutral;

commanding the electric machine to cease operating in a torque generating mode; and

electrically disconnecting the energy storage device from the inverter device.

2. The method of claim 1, wherein detecting the shutdown event comprises detecting one of an operator-initiated shutdown event, a fault-initiated shutdown event and an externally-initiated shutdown event.

3. The method of claim 2, further comprising commanding switching of transistors of the inverter device to isolate electric current generated by the electric machine from the energy storage device prior to electrically disconnecting the energy storage device from the inverter device when the externally-initiated shutdown event is detected.

4. The method of claim 3, wherein the energy storage device is electrically disconnected from the inverter device a calibrated elapsed period of time after isolating the electric current generated by the electric machine from the energy storage device.

5. The method of claim 3, comprising commanding each of the transistors of the inverter device to a continuously open position to isolate electric current generated by the electric machine from the energy storage device.

6. The method of claim 2, wherein detecting the operator-initiated shutdown event comprises detecting an operator-commanded powertrain shutdown.

7. The method of claim 2, wherein detecting the fault-initiated shutdown event comprises:

monitoring temperatures of the inverter and the electric machine and determining the temperature of one of the inverter and the electric machine is above a threshold temperature;

monitoring a voltage level of the energy storage device and determining the voltage level of the energy storage device is outside a predetermined voltage range; and

monitoring a current flow between the electric machine and the inverter device and determining the current flow is outside a predetermined current range.

8. The method of claim 2, wherein detecting the externally-initiated shutdown event further comprises:

determining a vehicle roll level greater than a threshold vehicle roll level;

detecting deployment of a vehicle airbag; and

detecting a change in vehicle inertia greater than a threshold inertia level.

9. The method of claim 2, further comprising:

monitoring a current level of the energy storage device; and

waiting a predetermined time period and then electrically disconnecting the energy storage device from the inverter device when the current level is not less than a threshold current level.

10. The method of claim 9, wherein the threshold current level comprises a first current level for the operator-initiated shutdown event and a second current level, greater than the first current level, for the externally-initiated shutdown event.

11. The method of claim 2, further comprising:

monitoring a rotational speed level of the electric machine; and

waiting a selected time period before electrically disconnecting the energy storage device from the inverter device when the speed level of the electric machine is not below a threshold electric machine speed.

12. The method of claim 11, wherein the threshold electric machine speed comprises a first speed level for the operator-initiated shutdown event and a second speed level, greater than the first speed level, for the externally-initiated shutdown event.

13. The method of claim 2, further comprising opening a contactor switch between the inverter device and the energy storage device to electrically disconnect the energy storage device from the inverter device, wherein opening of the contactor switch occurs after a first time period when the operator-initiated shutdown event is detected and after a second time period when the externally-initiated shutdown event is detected.

14. The method of claim 13, wherein the first time period is shorter than the second time period.

15. The method of claim 14, wherein opening the contactor switch occurs after a third time period when the fault-initiated shutdown event is detected, wherein said third time period is intermediate the first and second time periods.

16. The method of claim 1, further comprising commanding a shutoff of a high voltage load.

17. A method for operating a powertrain comprising an electromechanical transmission operatively connected to an engine and an electric machine to transmit tractive torque to an output shaft, the electric machine electrically connected to an inverter device electrically connected to an energy storage device, the method comprising:

detecting a shutdown event comprising one of an operator-initiated shutdown event, a fault-initiated shutdown event and an externally-initiated shutdown event;

implementing a first high voltage management strategy when the operator-initiated shutdown event is detected,

implementing a second high voltage management strategy when the fault-initiated shutdown event is detected, and

implementing a third high voltage management strategy when the externally-initiated shutdown event is detected.

18. The method of claim 17, wherein detecting the fault-initiated shutdown event comprises:

determining a temperature of one of the inverter and the electric machine exceeds a threshold temperature;

determining a voltage level of the energy storage device is outside a predetermined voltage range; and

determining an electrical current level between the electric machine and the inverter device is outside a predetermined current range.

19. The method of claim 17, wherein detecting the externally-initiated shutdown event further comprises:

determining a vehicle roll level greater than a threshold vehicle roll level;

detecting deployment of an vehicle airbag; and

detecting a change in vehicle inertia greater than a threshold inertia level.

20. A method for managing power in an electric circuit of a hybrid transmission, the electric circuit including a capacitive circuit electrically connected to an inverter circuit and selectively electrically connected to an energy storage device and to an active discharge circuit;

said inverter circuit electrically connected to an electric machine, the transmission operative to transmit torque between an input member and the electric machine and an output member, the method comprising;

providing the capacitive circuit electrically connected to the inverter circuit and electrically disconnected from the active discharge circuit;

detecting a shutdown event;

electrically connecting the active discharge circuit to the capacitive circuit;

measuring voltage across the capacitive circuit; and

routing electrical current from the capacitive circuit through the inverter circuit to the electric machine when the voltage across the capacitive circuit exceed the threshold voltage after a predetermined time period subsequent to detecting the shutdown event.