Method and apparatus to control engine restart for a hybrid powertrain system

• US 7,996,145 B2
• Filed: 05/03/2007
• Issued: 08/09/2011
• Est. Priority Date: 05/03/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Snyder, Bryan R.
• Primary Examiner(s): Wolfe, Jr.; Willis R
• Assistant Examiner(s): Hoang; Johnny H
• Application Number:
  US11/743,919
• Publication Number:
  US 20080275624A1
• Time in Patent Office: 1,559 Days
• Field of Search: 701/104, 701/105, 701/112, 701/113, 701/115, 477/3, 477/6, 903/905, 290/18, 180 651- 654, 1231793-1795, 123/179.16
• US Class Current: 701/104
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• 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 2240/445 Temperature
• 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 10/115 with planetary gears
• 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 20/15 Control strategies specially adapted for achieving a particular effect
• 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 2510/0671 Engine manifold pressure
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2510/104 Output speed
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 : Longitudinal speed
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2540/16 : Ratio selector position
• CPC Class Codes: B60W 2555/20 : Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/0644 : Engine speed
• CPC Class Codes: B60W 2710/083 : Torque
• 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
• CPC Class Codes: Y10S 903/905 : Combustion engine

Abstract

There is provided a control scheme for restarting an internal combustion engine of a hybrid powertrain during ongoing vehicle operation. The method includes generating a torque output from an electrical machine to rotate the engine, and determining an engine crank torque. The torque output from the electrical machine is selectively controlled based upon the engine crank torque. The engine is fired when rotational speed of the engine exceeds a threshold. An engine torque simulation model accurately determines engine compression pressures in real-time to accommodate changes in engine operating conditions, based upon present engine operating conditions.

Claims

1. Method for restarting an internal combustion engine of a hybrid powertrain during ongoing vehicle operation, the method comprising:

generating a torque output from an electrical machine to rotate the engine;

determining an engine crank torque;

selectively controlling the torque output from the electrical machine based upon the engine crank torque; and

,

firing the engine only when rotational speed of the engine exceeds a threshold.

2. The method of claim 1, wherein determining the engine crank torque comprises executing an engine torque simulation model to determine the engine crank torque based upon present engine operating conditions.

3. The method of claim 2, wherein selectively controlling the torque output from the electrical machine based upon the engine crank torque comprises executing a feed-forward control scheme to substantially counteract variations in the engine crank torque determined by the engine torque simulation model.

4. The method of claim 3, further comprising selectively controlling the torque output from the electrical machine to substantially counteract variations in the engine crank torque resulting from in-cylinder pressure variations.

5. The method of claim 1, wherein generating a torque output from an electrical machine to rotate the engine comprises:

determining a preferred engine operating speed required to restart the engine; and

,

controlling electrical energy transferred to the electrical machine based upon an input speed profile to achieve the preferred operating speed.

6. The method of claim 1, wherein firing the engine comprises injecting a quantity of fuel and initiating spark ignition to power the engine.

7. The method of claim 6, further comprising initiating the spark ignition at a spark timing to achieve operation at a substantially minimal engine torque output.

8. The method of claim 7, further comprising subsequently controlling the spark timing to achieve engine operation at a mean-best-torque output.

9. The method of claim 1, wherein firing the engine comprises injecting a quantity of fuel into the engine to power the engine.

10. Method for restarting an internal combustion engine during ongoing operation of a powertrain system comprising the internal combustion engine operatively connected to an electro-mechanical transmission and first and second electrical machines selectively operative to transmit torque therebetween, comprising:

generating torque output from the first and second electrical machines to rotate the engine;

determining an engine crank torque;

executing a feed-forward control scheme to selectively control the torque output from the first and second electrical machines to rotate the engine based upon the engine crank torque; and

,

firing the engine only when rotational speed of the engine exceeds a threshold.

11. The method of claim 10, wherein determining the engine crank torque comprises executing an engine torque simulation model to determine the engine crank torque based upon present engine operating conditions.

12. The method of claim 11, further comprising executing the feed-forward control scheme substantially counteract variations in the engine crank torque determined by the engine torque simulation model.

13. The method of claim 10, wherein generating torque output from the first and second electrical machines to rotate the engine further comprises:

determining a preferred engine operating speed required to restart the engine; and

,

controlling electrical energy transferred to the electrical machine based upon an input speed profile to achieve the preferred operating speed.

14. The method of claim 10, further comprising:

controlling a damper clutch to lock rotation of the engine and the transmission prior to generating the torque output from the electrical machine to rotate the engine; and

, unlocking the locked damper clutch prior to firing the engine.

15. The method of claim 10, wherein the torque output from the first and second electrical machines is limited based upon electrical energy capacity of an electrical energy storage device operative to supply electrical energy thereto.

16. The method of claim 10, wherein firing the engine when rotational speed of the engine exceeds a threshold comprises injecting a quantity of fuel and initiating spark ignition to power the engine when the engine comprises a spark-ignition engine.

17. The method of claim 16, further comprising initiating the spark ignition at a spark timing initially to generate a minimum engine torque output.

18. Article of manufacture, comprising a storage medium having a machine-executable program encoded therein for restarting an internal combustion engine of a hybrid powertrain during ongoing vehicle operation the powertrain comprising the internal combustion engine an electrical machine and an electro-mechanical transmission selectively operative to transmit torque therebetween, the program comprising:

code to generate a torque output from the electrical machine to rotate the engine;

code to determine an engine crank torque;

code to selectively control the torque output from the electrical machine based upon the engine crank torque; and

,

code to fire the engine only when rotational speed of the engine exceeds a threshold.

19. The article of manufacture of claim 18, wherein the code to determine engine crank torque comprises code to execute an engine torque simulation model to determine engine crank torque based upon present operating conditions.

20. The article of manufacture of claim 19, further comprising the engine compression torque simulation model to determine engine torque over a range of ambient and operating conditions.

21. The article of manufacture of claim 19, wherein the code to selectively control the torque output from the electrical machine comprises code to execute a feed-forward control scheme to substantially counteract variations in the engine crank torque determined by the engine torque simulation model.

22. The article of manufacture of claim 19, wherein the code to determine the engine crank torque comprises code to determine the engine crank torque coincident with an initiation of controlling torque output from the electrical machine to rotate the engine.