Multi-phase engine stop position control

• US 8,770,173 B2
• Filed: 04/14/2010
• Issued: 07/08/2014
• Est. Priority Date: 04/14/2010
• 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: Han, Jun, Wang, Lan, Tamai, Goro
• Primary Examiner(s): Vo, Hieu T
• Assistant Examiner(s): Castro, Arnold
• Application Number:
  US12/759,898
• Publication Number:
  US 20110253099A1
• Time in Patent Office: 1,546 Days
• Field of Search: 123/350, 123/179.3, 123/179.4, 903/905, 903/906, 701/112
• US Class Current: 123/350
• CPC Class Codes: F02D 2041/0095 Synchronisation of the cylinders during engine shutdown
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 41/0097 using means for generating speed signals
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/065 at hot start or restart F02D41/067 takes precedence
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 11/0818 Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode
• CPC Class Codes: F02N 19/005 Aiding engine start by starting from a predetermined position, e.g. pre-positioning or reverse rotation
• CPC Class Codes: F02N 2019/008 the engine being stopped in a particular position

Abstract

A method is provided for controlling engine stop position in a vehicle having an engine with auto stop/auto start functionality. The method includes automatically ramping down engine speed upon initiation of an auto stop event, executing closed-loop speed control of the engine when the engine speed begins to ramp down, and for as long as the engine speed remains above a threshold engine speed while ramping down the engine speed; executing closed-loop position control of the engine while ramping down the engine speed once the engine speed is less than the threshold engine speed and greater than zero; and stopping the crankshaft to within a calibrated range of a targeted engine stop position. A controller is also provided that includes a hardware module and an algorithm adapted for executing the foregoing method, and a vehicle is provided having an engine with auto stop/start functionality and the controller noted above.

Claims

1. A vehicle comprising:

an engine with a crankshaft and auto start/auto stop functionality;

a transmission having a transmission state; and

a proportional-integral (PI) controller adapted for controlling a cranking position of the engine during an auto stop event, wherein the PI controller is in communication with the engine, and is configured for;

automatically ramping down engine speed upon initiation of an auto stop event;

executing closed-loop speed control of the engine when the engine speed begins to ramp down, and for as long as the engine speed remains above a threshold engine speed while ramping down the engine speed;

setting an I-term of the PI controller as a function of at least the transmission state and a speed of the vehicle;

after setting the I-term, executing closed-loop position control of the engine while ramping down the engine speed when a predetermined condition is detected; and

stopping the crankshaft to within a calibrated range of a targeted engine stop position.

2. The vehicle of claim 1, wherein the algorithm is further adapted for switching back to closed-loop speed control of the engine once the engine speed equals zero.

3. The vehicle of claim 2, wherein the predetermined condition includes one of:

the engine speed being less than the threshold engine speed and greater than zero, and an engine profile position passing a calibrated trigger position.

4. The vehicle of claim 2, wherein the algorithm is further adapted for:

calculating a changing angular value of the crankshaft; and

using the changing angular value of the engine as a closed-loop feedback variable during the closed-loop position control.

5. The vehicle of claim 2, wherein the algorithm is further adapted for:

determining if a set of exit conditions is present when the engine is stopped; and

transitioning from closed-loop position control to closed-loop speed control only if the set of exit conditions is present.

6. A proportional-integral (PI) controller for use aboard a vehicle having a transmission and an engine with a crankshaft and auto stop/auto start functionality, the controller comprising a hardware module and an algorithm adapted for controlling a cranking position of the engine during an auto stop event, wherein the algorithm is adapted for:

automatically ramping down engine speed upon initiation of an auto stop event;

executing closed-loop speed control of the engine when the engine speed begins to ramp down, and for as long as the engine speed remains above a threshold engine speed while ramping down the engine speed;

setting an I-term of the PI controller as a function of at least a state of the transmission and a speed of the vehicle;

after setting the I-term, executing closed-loop position control of the engine while ramping down the engine speed when a predetermined condition is detected; and

stopping the crankshaft to within a calibrated range of a targeted engine stop position.

7. The controller of claim 6, wherein the algorithm is further adapted for switching back to closed-loop speed control of the engine once the engine speed equals zero.

8. The controller of claim 6, wherein the predetermined condition includes one of:

the engine speed being less than the threshold engine speed and greater than zero, and an engine profile position passing a calibrated trigger position.

9. The controller of claim 6, wherein the algorithm is further adapted for:

calculating a changing angular value of the crankshaft; and

using the changing angular value of the engine as a closed-loop feedback variable during the closed-loop position control.

10. The controller of claim 6, wherein the algorithm is further adapted for:

determining if a set of exit conditions is present when the engine is stopped; and

transitioning from closed-loop position control to closed-loop speed control only if the set of exit conditions is present.

11. A method for controlling an engine stop position in a vehicle having a proportional-integral (PI) controller, a transmission having a transmission state, and an engine with auto stop/auto start functionality and a crankshaft, the method comprising:

automatically ramping down engine speed upon initiation of an auto stop event;

executing closed-loop speed control of the engine when the engine speed ramps down, and for as long as the engine speed remains above a threshold engine speed;

setting an I-term of the PI controller as a function of at least the transmission state and a speed of the vehicle;

after setting the I-term, executing closed-loop position control of the engine while ramping down the engine speed when a predetermined condition is detected; and

stopping the crankshaft of the engine to within a calibrated range of a targeted engine stop position.

12. The method of claim 11, further comprising:

switching back to closed-loop speed control of the engine once the engine speed equals zero.

13. The method of claim 11, wherein the predetermined condition includes one of:

the engine speed being less than the threshold engine speed and greater than zero, and an engine profile position passing a calibrated trigger position.

14. The method of claim 11, further comprising:

calculating a changing angular value of the crankshaft; and

using the changing angular value of the engine as a closed-loop feedback variable during the closed-loop position control.

15. The method of claim 11, further comprising:

determining if a set of exit conditions is present when the engine is stopped; and

transitioning from closed-loop position control to closed-loop speed control only if the set of exit conditions is present.