SYSTEMS AND METHODS FOR OPTIMIZATION AND CONTROL OF INTERNAL COMBUSTION ENGINE STARTING

• US 20150211466A1
• Filed: 04/08/2015
• Published: 07/30/2015
• Est. Priority Date: 10/29/2012
• Status: Active Grant

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Puri, Anant, Zeng, Fan, Sujan, Vivek, Hodzen, Edmund, Bruner, C. Larry
• Granted Patent: US 9,709,014 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60W 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 41/062 for starting F02D41/061 takes precedence
• CPC Class Codes: F02N 11/08 Circuits or control means specially adapted for starting of engines
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 11/0822 related to action of the driver
• CPC Class Codes: F02N 11/0825 related to prevention of engine restart failure, e.g. disabling automatic stop at low battery state
• CPC Class Codes: F02N 11/0844 with means for restarting the engine directly after an engine stop request, e.g. caused by change of driver mind
• CPC Class Codes: F02N 11/0851 characterised by means for controlling the engagement or disengagement between engine and starter, e.g. meshing of pinion and engine gear
• CPC Class Codes: F02N 2200/022 Engine speed
• CPC Class Codes: F02N 2200/023 Engine temperature
• CPC Class Codes: F02N 2200/04 said parameters being related to the starter motor
• CPC Class Codes: F02N 2200/061 Battery state of charge [SOC]
• CPC Class Codes: F02N 2200/101 Accelerator pedal position
• CPC Class Codes: F02N 2300/102 Control of the starter motor speed; Control of the engine speed during cranking

Abstract

An engine starting system and technique include selecting a target engine speed profile from a plurality of engine speed profiles based on operator inputs and operating parameters of the vehicle. A feedback control strategy is used to substantially conform the engine speed with the target speed profile during starting until a target speed is reached in which fueling is initiated to start the engine.

Claims

1. A method, comprising:

maintaining a plurality of engine speed profiles for starting an internal combustion engine of a vehicle;

selecting a target engine speed profile from the plurality of engine speed profiles based on operator inputs from an operator of the vehicle and operating parameters of the vehicle;

driving the internal combustion engine with a starter motor in response to selecting the target engine speed profile;

determining an instantaneous engine speed during the starting duration;

regulating the speed of the internal combustion engine during the starting duration in response to the instantaneous engine speed to substantially conform the speed of the internal combustion engine with the target speed profile; and

starting the internal combustion engine when the speed of the internal combustion engine reaches a target speed of the target speed profile.

2. The method of claim 1, wherein the starter motor is at least one of a motor-generator and a starter.

3. The method of claim 1, wherein the operator inputs include an accelerator pedal position.

4. The method of claim 1, wherein the operating parameters include at least one of an engine temperature, a state of charge of an energy storage device, a torque demand, and a state of at least one starter motor.

5. The method of claim 1, wherein:

each of the plurality of engine speed profiles includes a plurality of operating characteristics including at least two or more of a starting duration, an entry acceleration, a mid-way speed, an exit acceleration, and the target speed; and

at least one of the operating characteristics differs for each of the engine speed profiles.

6. The method of claim 1, wherein the target speed includes a first threshold.

7. The method of claim 6, wherein the target speed includes a second threshold that is greater than the first threshold.

8. The method of claim 1, wherein selecting the target speed profile includes determining at least one of a starting failure probability, a starting duration, a peak torque required to start the engine, and noise and vibration of the engine during starting.

9. The method of claim 1, wherein selecting the target engine speed profile further includes determining an engine crank revolution count provided by the target engine speed profile satisfies a minimum crank revolution count before starting the engine.

10. The method of claim 9, wherein the engine crank revolution count is determined in response to an engine crank angle, a total engine cranking process time, and an engine cranking starting time.

11. The method of claim 1, wherein selecting the target speed profile includes determining at least one of a peak torque of the starter motor, a peak power of the starter motor, a maximum discharge current of an energy storage device connected to the starter motor, and an available state-of-charge of the energy storage device.

12. A method, comprising:

operating a vehicle with a powertrain to satisfy a driver torque demand, and while operating the vehicle;

selecting a target engine speed profile from a plurality of engine speed profiles stored in a controller of the vehicle, wherein selecting the target speed profile includes interpreting operator inputs and operating parameters of the vehicle with the controller to determine the target speed profile;

providing a control command to a starter motor to drive the internal combustion engine according to the target speed profile over a starting duration;

determining the instantaneous engine speed during the starting duration;

modifying the control command during the starting duration to regulate the speed of the internal combustion engine to substantially conform with the target speed profile based on the instantaneous speed determination; and

fueling the internal combustion engine when an actual speed of the internal combustion engine is within a region around a first threshold target speed of the target speed profile.

13. The method of claim 12, wherein selecting the target engine speed profile further includes determining an engine crank condition of the target speed profile satisfies a minimum number of engine crank revolutions before fueling the internal combustion engine.

14. The method of claim 13, wherein:

the engine crank condition is determined by a crank revolution function in response to engine crank angle, total engine cranking process time, and engine cranking starting time; and

wherein the engine crank angle is determined by a net total crank revolutions determined as a function of time.

15. The method of claim 12, wherein:

the starter motor is an electromechanical device of the power train;

the electromechanical device is selectively engageable to the internal combustion engine with a friction clutch; and

the electromechanical device is operable to satisfy the driver torque demand in an electric drive mode.

16. The method of claim 12, wherein the starter motor is a starter connected to the powertrain with a gearbox.

17. The method of claim 12, wherein the starter motor is selected from a starter connected to the powertrain with a gearbox and an electromechanical device selectively coupled to the internal combustion engine with a friction clutch.

18. A system, comprising:

a powertrain including an internal combustion engine having an output shaft;

at least one starter motor operable to rotate the output shaft of the internal combustion during starting of the internal combustion engine;

a controller in communication with the internal combustion engine and the starter motor configured to initiate starting of the internal combustion engine, the controller comprising;

an engine speed profile selection module configured to determine a target speed profile for starting the internal combustion engine, wherein the engine speed profile selection module is further configured interpret operator inputs and operating parameters of the internal combustion engine to select the target speed profile from a plurality of engine speed profiles stored in a memory of the controller; and

a starter motor command module configured to determine a control command for the starter motor to rotate the output shaft of the internal combustion engine in response to the selected target speed profile, wherein the starter motor command module is configured to regulate the control command over a starting duration in response to an instantaneous engine speed determination to substantially conform the speed of the internal combustion engine with the target speed profile during the starting duration.

19. The system of claim 18, wherein the at least one starter motor includes an electromechanical device selectively coupled to output shaft of the internal combustion engine with a friction clutch, wherein the internal combustion engine and the electromechanical device are each operable to satisfy an operator torque demand.

20. The system of claim 19, wherein the at least one starter motor includes a starter connected to the output shaft of the internal combustion engine with a gearbox.

21. The system of claim 20, wherein the electromechanical device is a motor-generator.

22. The system of claim 18, wherein the at least one starter motor includes a starter connected to the output shaft of the internal combustion engine with a gearbox.

23. The system of claim 18, wherein:

each of the plurality of engine speed profiles includes a plurality of operating characteristics including at least two or more of a starting duration, an entry acceleration, a mid-way speed, an exit acceleration, and the target speed; and

at least one of the operating characteristics differs for each of the engine speed profiles.

24. The system of claim 18, wherein the controller is configured to select the target speed profile by interpreting at least one of a starting failure probability, a starting duration, a peak torque required to start the engine, noise and vibration of the engine during starting, a peak torque of the starter motor, a peak power of the starter motor, a maximum discharge current of an energy storage device connected to the starter motor, and an available state-of-charge of the energy storage device.

25. The system of claim 18, wherein the engine speed profile selection module is further configured to determine a number of total engine crank revolutions utilizing the equation:

26. The system of claim 25, wherein the engine speed profile is determined utilizing the equation:

{dot over (θ

)}=f(t)= . . . +a*t⁴+b*t³+c*t²+d*t+e

wherein a, b, c, d, and e are coefficients to fit an engine speed profile at a time t and the equation is an n^th-order equation where n is greater than or equal to 1.