Hybrid vehicle auto start systems and methods

• US 8,157,035 B2
• Filed: 01/13/2009
• Issued: 04/17/2012
• Est. Priority Date: 08/15/2008
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Whitney, Christopher E., Bryde, Steven G., Schwenke, R. Travis, Lahti, John L., Jin, Ning, Bhattarai, Birendra P., Williams, Cheryl A., Nicholson, James B
• Primary Examiner(s): Shriver, II, J. Allen
• Assistant Examiner(s): Gurari, Erez
• Application Number:
  US12/352,813
• Publication Number:
  US 20100038158A1
• Time in Patent Office: 1,190 Days
• Field of Search: 180/65.265, 180 6521- 6529
• US Class Current: 180/65.265
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/485 Motor-assist 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 2240/486 Operating parameters
• 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2050/0006 Digital architecture hierarchy
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 2510/105 Output torque
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2710/0605 Throttle position
• CPC Class Codes: B60W 2710/0616 Position of fuel or air injector
• CPC Class Codes: B60W 2710/0666 : Engine torque
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 30/16 : Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: B60W 30/18 : Propelling the vehicle
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

A method of operating an engine control system includes reducing pressures within cylinders of an engine based on an auto start command signal including: receiving a torque request signal; calculating a powertrain output torque; and controlling air flow to the engine based on the powertrain output torque. During a startup of the engine: electric motor torque is increased to a predetermined level and reduced to increase a current speed of the engine; combustion torque of the engine is activated and increased after the current speed is within a predetermined range and a manifold absolute pressure is less than a predetermined level; and the electric motor torque is increased based on a crankshaft output torque signal to increase a crankshaft output torque subsequent to the reducing of the electric motor torque and while performing the activating of the combustion torque.

Claims

1. A method of operating an engine control system comprising:

receiving an auto start command signal;

reducing pressures within cylinders of an engine based on the auto start command signal comprising;

receiving a torque request signal corresponding to at least one of spark and fuel;

calculating a powertrain output torque based on engine air flow commands of an engine control module; and

controlling air flow to the engine based on the powertrain output torque; and

during a startup of the engine;

increasing electric motor torque to a first predetermined level to overcome friction and pumping pressures of the engine;

reducing electric motor torque to ramp up a current speed of the engine and to engage a transmission;

activating and increasing combustion torque of the engine after the current speed of the engine is within a predetermined range of an idle speed and after a manifold absolute pressure of the engine is less than a second predetermined level;

generating a crankshaft output torque signal subsequent to the reducing of the electric motor torque; and

increasing the electric motor torque based on the crankshaft output torque signal to increase a crankshaft output torque of the engine subsequent to the reducing of the electric motor torque and while performing the activating of the combustion torque of the engine.

2. The method of claim 1 wherein receiving an auto start command signal comprises at least one of receiving a brake signal, receiving an accelerator signal, receiving an air conditioning activation signal, and receiving a regeneration signal.

3. The method of claim 1 wherein reducing pressures within the cylinders of the engine comprises increasing the electric motor torque to increase the current speed.

4. The method of claim 1 wherein:

fuel to the engine is enabled when the current speed of the engine is greater than or equal to a third predetermined level and based on an accelerator pedal position;

fuel to the engine is enabled in a normal mode when the manifold absolute pressure of the engine is less than a fourth predetermined level; and

fuel to the engine is enabled in an aggressive mode when the transmission is engaged based on speed of the engine.

5. The method of claim 1 wherein fuel to the engine is enabled when the engine is activated.

6. The method of claim 1 further comprising transferring control of the current speed from a hybrid control module to the engine control module when at least one of the combustion torque is activated and greater than a third predetermined level and the current speed is greater than or equal to an idle speed.

7. The method of claim 1 wherein air flow to the engine is controlled by the engine control module,

wherein the engine control module pumps down the manifold absolute pressure by adjusting air flow across a throttle to a predetermined air flow level, and then

wherein the engine control module adjusts the air flow across the throttle to provide a requested torque output.

8. The method of claim 1 further comprising increasing combustion torque of the engine to reduce the electric motor torque to zero when control of the current speed of the engine is transferred from a hybrid control module to the engine control module.

9. The method of claim 1 further comprising transferring control of the current speed of the engine after activation of the combustion torque of the engine,

wherein when control of the current speed of the engine is transferred from a hybrid control module to the engine control module a closed loop error of the hybrid control module is maintained at a constant level and is transmitted to the engine control module.

10. The method of claim 1 further comprising wherein the engine control module switches from an idle speed control mode that is controlled by a hybrid control module to a driver torque request mode that is controlled by the engine control module based on an accelerator signal.

11. The method of claim 10 wherein the engine control module controls electric motor torque based on a difference between a crankshaft torque and a WOM torque, where WOM torque is combustion torque of the engine minus brake torque without electric motor torque applied.

12. The method of claim 1 further comprising:

operating the engine control module in a first mode and a second mode;

generating a transmission load signal based on the idle speed;

increasing the electric motor torque to increase the current speed based on the idle speed and the transmission load signal via a hybrid control module during the first mode;

controlling the current speed via the engine control module when in the second mode; and

transferring control of the current speed from the hybrid control module to the engine control module when at least one of the current speed matches the idle speed and a combustion torque output of the engine is equal to a requested crankshaft output torque.

13. The method of claim 12 further comprising:

generating a brake signal;

operating the engine control module and the hybrid control module in the first mode; and

determining the idle speed and generating the transmission load signal based on the brake signal via the engine control module.

14. The method of claim 12 further comprising:

generating an accelerator signal; and

transferring control of the current speed from the hybrid control module to the engine control module (i) before the combustion torque output is equal to the requested crankshaft output torque and (ii) before the current speed is greater than or equal to the idle speed based on the accelerator signal.

15. The method of claim 12 further comprising controlling throttle position of the engine via the engine control module based on at least one of a cranking cylinder event and a coolant temperature.

16. The method of claim 12 further comprising reducing throttle area when in the first mode via the engine control module to reduce pressures in cylinders of the engine.

17. The method of claim 12 further comprising adjusting a torque request corresponding to at least one of spark and fuel via the hybrid control module when in the first mode.

18. The method of claim 12 further comprising advancing spark timing via the engine control module when in the second mode based on a torque request.

19. The method of claim 12 further comprising:

estimating torque output of the engine via the engine control module; and

controlling the electric motor torque based on the estimated torque output via the hybrid control module.

20. The method of claim 12 further comprising ramping the combustion torque from a friction torque level of the engine to an idle speed torque level that corresponds with a steady state transmission load via the engine control module based on the torque request signal from the hybrid control module.

21. The method of claim 1, further comprising:

decreasing the electric motor torque subsequent to the increasing of the electric motor torque based on the crankshaft output torque signal; and

increasing a combustion torque request while performing the activating and increasing of the combustion torque of the engine.

22. A method of operating an engine control system comprising:

receiving an auto start command signal;

reducing pressures within cylinders of an engine based on the auto start command signal comprising;

receiving a torque request signal corresponding to at least one of spark and fuel;

calculating a powertrain output torque based on engine air flow commands of an engine control module; and

controlling air flow to the engine based on the powertrain output torque;

increasing electric motor torque to a first predetermined level to overcome friction and pumping pressures of the engine;

reducing electric motor torque to ramp up a current speed of the engine and to engage a transmission;

activating and increasing combustion torque of the engine after the current speed of the engine is within a predetermined range of an idle speed and after a manifold absolute pressure of the engine is less than a second predetermined level; and

transferring control of the current speed from a hybrid control module to the engine control module when at least one of the combustion torque is activated and the current speed is greater than or equal to the idle speed.

23. The method of claim 22, further comprising:

controlling the current speed of the engine via the hybrid control module by adjusting the electric motor torque when in a first mode; and

controlling the current speed of the engine via the engine control module by adjusting a WOM torque when in a second mode, where the WOM torque is a combustion torque of the engine minus brake torque without electric motor torque applied.

24. The method of claim 22, further comprising:

determining an electric motor torque error;

transmitting the electric motor torque error from the hybrid control module to the engine control module during the transfer of control of the current speed from the hybrid control module to the engine control module; and

adjusting the electric motor torque error via the engine control module.