METHODS AND SYSTEMS FOR ASSISTED DIRECT START CONTROL

• US 20100174473A1
• Filed: 01/05/2009
• Published: 07/08/2010
• Est. Priority Date: 01/05/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Surnilla, Gopichandra, Ulrey, Joseph Norman, Russell, John D., Lewis, Donald, Pursifull, Ross Dykstra
• Granted Patent: US 8,370,051 B2
• Time in Patent Office: Days
• US Class Current: 701/112
• CPC Class Codes: F02D 31/001 Electric control of rotation speed
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02N 11/00 Starting of engines by means of electric motors
• 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 11/0855 during engine shutdown or after engine stop before start command, e.g. pre-engagement of pinion
• CPC Class Codes: F02N 15/003 Starters comprising a brake mechanism
• CPC Class Codes: F02N 2200/022 Engine speed
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Method and systems are provided for controlling a vehicle system including an engine that is selectively deactivated during engine idle-stop conditions. One example method comprises, adjusting a brake torque applied to a deactivated rotating engine after an engine restart request, the brake torque applied to slow the engine to at least a predetermined threshold speed without stopping the engine, and engaging a starter to the still rotating engine to increase the engine speed and restart the engine.

Claims

1. A method of controlling a vehicle system including an engine that is selectively deactivated during engine idle conditions, the method comprising:

adjusting a brake torque applied to a deactivated rotating engine after an engine restart request, the brake torque applied to slow the engine to at least a predetermined threshold speed without stopping the engine; and

engaging a starter to the still rotating engine to increase the engine speed and restart the engine.

2. The method of claim 1 wherein the engine starter is engaged at a predetermined engine speed.

3. The method of claim 2 wherein the predetermined engine speed varies as engine operating conditions vary.

4. The method of claim 1 wherein engine fuel and spark are reactivated to start the engine after the starter is engaged.

5. The method of claim 3 wherein engine operating conditions include engine temperature.

6. A method of controlling a vehicle system including an engine that is selectively shut-down during engine idle-stop conditions, the method comprising:

receiving an engine restart request from an operator during an engine idle-stop operation where the engine is not yet stopped;

adjusting a brake torque applied to the engine in response to the engine restart request, the brake torque applied to slow the engine to at least a predetermined threshold speed; and

once the at least a predetermined threshold speed is attained, engaging a starter to the still rotating engine to increase engine speed and restart the engine.

7. The method of claim 6 wherein adjusting the brake torque applied to the engine includes,

increasing the brake torque applied to the engine when the difference between engine speed at a time of restart request and the predetermined threshold speed is relatively larger;

and

decreasing the brake torque applied to the engine when the difference between engine speed at the time of restart request and the predetermined threshold speed is relatively smaller.

8. The method of claim 7 wherein the brake torque applied to the engine includes applying one or more of a reverse torque, a transmission drag torque, and a gas torque.

9. The method of claim 8 wherein applying a reverse torque to the engine includes, engaging a clutch of an alternator and/or engaging a clutch of an air conditioner compressor.

10. The method of claim 8 wherein applying a transmission drag torque to the engine includes engaging at least one transmission hydraulic component with the transmission in an engaged gear.

11. The method of claim 10 wherein the at least one of a transmission hydraulic component includes a forward clutch of the transmission and/or a torque converter clutch.

12. The method of claim 8 wherein applying a gas torque includes at least one of closing at least an intake valve of a cylinder while leaving an exhaust valve open, adjusting intake valve timing to a late intake valve closure, and advancing spark timing.

13. The method of claim 6 wherein the predetermined threshold speed is less than 100 rpm.

14. The method of claim 6 wherein the predetermined threshold speed is a speed range of 50-100 rpm.

15. A method of expediting engine spin-down in an engine that is shut-down during engine idle-stop conditions and restarted during restart conditions, the method comprising:

when an engine restart request is received from an operator during an engine idle-stop operation and where the engine is not yet stopped;

during a first restart condition, applying a brake torque to the engine, fully stopping the engine, and then engaging a starter to the stopped engine to increase engine speed and restart the engine;

during a second restart condition wherein engine speed at an occurrence of a restart request is above a predetermined threshold, applying the brake torque to the engine to slow the engine to at least a predetermined threshold speed, and after the at least a predetermined threshold speed is attained, engaging the starter to the still rotating engine to increase engine speed and restart the engine; and

during a third restart condition wherein the engine speed at the occurrence of the restart request is at or below the predetermined threshold, removing brake torque applied to the engine and engaging the starter to the still rotating engine to increase engine speed and restart the engine.

16. The method of claim 15 wherein the brake torque includes one or more of a reverse torque, a transmission drag torque, and a gas torque.

17. The method of claim 16 wherein the reverse torque is achieved by engaging a clutch of an alternator and/or engaging a clutch of an air conditioner compressor, the transmission drag torque is achieved by engaging at least one of a forward clutch and a torque converter clutch of the transmission, and the gas torque is achieved by at least one of closing an intake valve of a cylinder while leaving an exhaust valve open, adjusting intake valve timing to a late intake valve closure, and advancing spark timing.

18. The method of claim 15 wherein the predetermined threshold speed is below 100 rpm.

19. The method of claim 15 wherein the predetermined threshold speed is a speed range of 50-100 rpm.

20. The method of claim 15 wherein applying the brake torque to the engine includes,

increasing the brake torque applied to the engine when the difference between engine speed at the occurrence of restart request and the predetermined threshold speed is relatively larger;

and

decreasing the brake torque applied to the engine when the difference between engine speed at the occurrence of restart request and the predetermined threshold speed is relatively smaller.

21. A vehicle system, comprising:

a powertrain including wheels, an engine having a starter, a torque converter having a lock-up clutch, and an automatic transmission including a forward clutch;

an alternator including an alternator clutch;

an air conditioner including a compressor clutch;

a cylinder deactivation mechanism for deactivating at least a cylinder valve of a cylinder; and

a control system configured to deactivate the engine during engine idle-stop conditions and selectively restart the engine in response to an operator engine restart request, the restart request received during an idle-stop operation where the engine is not yet stopped, wherein selectively restarting the engine includes,

adjusting a brake torque applied to the engine to slow the engine to at least a predetermined threshold speed, and once the at least a predetermined threshold speed is attained, engaging the starter to the still rotating engine to increase engine speed and restart the engine when engine speed at a time of restart request is above the predetermined threshold; and

removing the brake torque applied to the engine and engaging the starter to the still rotating engine to increase engine speed and restart the engine when the engine speed at the time of restart request is at or below the predetermined threshold.

22. The system of claim 21 wherein adjusting the brake torque includes,

increasing the brake torque applied to the engine when the difference between engine speed at the time of restart request and the predetermined threshold speed is relatively larger;

and

decreasing the brake torque applied to the engine when the difference between engine speed at the time of restart request and the predetermined threshold speed is relatively smaller.

23. The system of claim 22 wherein the brake torque applied includes at least one of a reverse torque applied by engaging the alternator clutch and/or the compressor clutch, a transmission drag torque applied by engaging at least one of the forward clutch and the torque converter clutch, and a gas torque applied by at least one of closing an intake valve of the cylinder while leaving an exhaust valve open, adjusting the intake valve timing to a late intake valve closure, and advancing spark timing.

24. The system of claim 23 wherein the predetermined threshold speed is below 100 rpm.