METHOD AND DEVICE FOR CONTROLLING AN INTERNAL COMBUSTION ENGINE IN STOP/START OPERATION

• US 20090157284A1
• Filed: 12/10/2008
• Published: 06/18/2009
• Est. Priority Date: 12/13/2007
• Status: Active Grant

• Current Assignee: Vitesco Technologies GmbH (Continental AG)
• Original Assignee: Continental Automotive GmbH (Continental AG)
• Inventors: Hacker, Frank, Bayerle, Klaus
• Granted Patent: US 7,941,266 B2
• Time in Patent Office: Days
• US Class Current: 701/112
• CPC Class Codes: F02D 2200/1012 Engine speed gradient
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/1498 measuring engine roughness
• 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 19/00 Starting aids for combustion engines, not otherwise provided for
• CPC Class Codes: F02N 2300/2002 using different starting modes, methods, or actuators depending on circumstances, e.g. engine temperature or component wear
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In a method for controlling an internal combustion engine (1) for a motor vehicle in stop-start operation, the internal combustion engine (1) is operated in the idling operating state. If there is a request for switch-off of the internal combustion engine (1) the torque produced by the internal combustion engine (1) is reduced while fuel continues to be injected. The fuel injection is switched off if the speed of the internal combustion engine (1) reaches a predetermined minimum value. The torque produced by the internal combustion engine (1) is increased again if the request for switching off the internal combustion engine (1) is canceled before the minimum speed is reached.

Claims

1. A method for controlling an internal combustion engine for a motor vehicle in stop-start operation, comprising the steps of:

in the event of a request for the switch-off of the internal combustion engine, reducing the torque produced by the internal combustion engine while fuel injection is continued such that the speed of the internal combustion engine falls to below a predetermined setpoint idling speed,

wherein the fuel injection is only switched off if a condition is fulfilled.

2. The method according to claim 1, wherein the condition being fulfilled if the speed of the internal combustion engine has reached a predetermined minimum speed which is less than the setpoint idling speed.

3. The method according to claim 2, wherein the minimum speed being dimensioned so that at this minimum speed the torque produced by the internal combustion engine can no longer be increased.

4. The method according to claim 1, wherein uneven running of the internal combustion engine being determined and the condition being fulfilled if the uneven running exceeds a pre-determined limit value.

5. The method according to claim 1, wherein the torque produced by the internal combustion engine being increased again if the request for switch-off of the internal combustion engine is canceled again before the condition is fulfilled.

6. The method according to claim 1, wherein the internal combustion engine being operated such that the fuel last injected before the switching off of the fuel injection is burned.

7. The method according to claim 5, wherein the torque produced by the internal combustion engine being reduced and increased by appropriate variation of the ignition time.

8. The method according to claim 5, wherein the torque produced by the internal combustion engine being reduced and increased by appropriate variation of the quantity of fuel injected.

9. The method according to claim 5, wherein the request for switch-off of the internal combustion engine being made if the internal combustion engine is idling for longer than a predetermined period of time.

10. The method according to claim 1, wherein the torque produced by the internal combustion engine being reduced in such a way that the drop in speed of the internal combustion engine caused thereby occurs with a predetermined gradient.

11. The method according to claim 5, wherein the reduction and increase of the torque produced by the internal combustion engine being undertaken using an idling control.

12. A control device for an internal combustion engine of a motor vehicle, which is operable, in stop-start operation, such that

in the event of there being a request for the switch-off of the internal combustion engine the torque produced by the internal combustion engine is reduced while fuel injection is continued such that the speed of the internal combustion engine falls to below a predetermined setpoint idling speed, and

the fuel injection is only switched off if a condition is fulfilled.

13. The control device according to claim 12, wherein the condition being fulfilled if the speed of the internal combustion engine has reached a predetermined minimum speed which is less than the setpoint idling speed.

14. The control device according to claim 13, wherein the minimum speed being dimensioned so that at this minimum speed the torque produced by the internal combustion engine can no longer be increased.

15. The control device according to claim 12, further being operable to determine uneven running of the internal combustion engine and the condition being fulfilled if the uneven running exceeds a predetermined limit value.

16. The control device according to claim 12, further being operable to increase the torque produced by the internal combustion engine again if the request for switch-off of the internal combustion engine is canceled again before the condition is fulfilled.

17. The control device according to claim 12, wherein the internal combustion engine being operated such that the fuel last injected before the switching off of the fuel injection is burned.

18. The control device according to claim 17, wherein the torque produced by the internal combustion engine being reduced and increased by appropriate variation of the ignition time.

19. The control device according to claim 17, wherein the torque produced by the internal combustion engine being reduced and increased by appropriate variation of the quantity of fuel injected.

20. The control device according to claim 17, wherein the request for switch-off of the internal combustion engine being made if the internal combustion engine is idling for longer than a predetermined period of time.