Method and Control Unit for Variable Turbocharger Turbine Flow Cross-Section Control

Abstract

A method is used for activating an actuator to set a turbine flow cross-section of a motor vehicle turbocharger of a gasoline engine in the event of a change of the load of the engine from a smaller load value to a larger load value. The actuator for the larger load value is activated with a delay in relation to the load change. Furthermore, a control unit set up to control the sequence of the method is used to implement the method.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Several embodiments of the present invention are described in greater detail on the basis of the drawings, in which:

FIG. 1 is a schematic diagram showing an internal combustion engine having a turbocharger with variable turbine geometry;

FIG. 2 shows a schematic cross-sectional view showing the variation of the turbine geometry;

FIGS. 3 a-3c are, respectively, time curves of a driver command, a throttle valve adjustment, and an adjustment of a turbine flow cross-section in the event of a positive load change; and

FIG. 4 is a flowchart showing an exemplary embodiment of a method according to the present invention.

Claims

1. A method for operating an actuator to set a turbine flow cross-section of a motor vehicle gasoline engine turbocharger in the event of a change of gasoline engine load from a smaller load value to a larger load value, comprising operating the actuator to be set for the larger load value with a delay relative to the load change.

2. The method according to claim 1, wherein an extent of the delay is predetermined as a function of at least one gasoline engine operating parameter.

3. The method according to claim 2, wherein the at least one operating parameter is gasoline engine speed upon the load change.

4. The method according to claim 3, wherein the extent of the delay (tv) is larger at a smaller value of the gasoline engine speed than at a larger value thereof.

5. The method according claim 3, wherein a further operating parameter is a gasoline engine load before the load change.

6. The method according to claims 5, wherein the extent of the delay (tv) is larger at a smaller value of the gasoline engine speed than at a larger value thereof.

7. The method according to claim 3, wherein a further operating parameter is a gasoline engine exhaust gas temperature upon the load change.

8. The method according to claim 7, wherein the extent of the delay (tv) is larger at a smaller value of the gasoline engine speed than at a larger value thereof.

9. The method according to claim 8, wherein a further operating parameter is a gasoline load before the load change.

10. The method according to claim 3, wherein the at least one operating parameter is an operating parameter dependent on gasoline engine surroundings.

11. The method according to claim 10, wherein the at least one operating parameter is air pressure in the gasoline engine surroundings.

12. The method according to claim 10, wherein the at least one operating parameter is air temperature in the surroundings.

13. The method according to claim 12, wherein the at least one operating parameter is air pressure in the gasoline engine surroundings.

14. A control unit configured to operate an actuator to set a motor vehicle gasoline engine turbocharger turbine flow cross-section in the event of a gasoline engine load change from a smaller load value to a larger load value, comprising means for setting the turbine flow cross-section for the larger load value with a delay relative to the load change.

15. The control unit according to claim 14, wherein the means controls such that an extent of the delay is predetermined as a function of at least one gasoline engine operating parameter.

16. The control unit according to claim 15, wherein the at least one is gasoline engine speed upon the load change.

17. The control unit according to claim 16, wherein the extent of the delay (tv) is larger at a smaller value of the gasoline engine speed than at a larger value thereof.

18. The control unit according to claim 16, wherein a further operating parameter is a gasoline engine load before the load change.

19. The control unit according to claim 16, wherein a further operating parameter is a gasoline engine exhaust gas temperature upon the load change.

20. The control unit according to claim 16, wherein at least one operating parameter is an operating parameter dependent on gasoline engine surroundings.

21. The control unit according to claim 20, wherein the at least one operating parameter is air pressure in the gasoline engine surroundings.

22. The control unit according to claim 20, wherein the at least one operating parameter is air temperature in the surroundings.