Method and control unit for setting a turbine flow cross-section
View Patent ↗A turbine flow cross-section of a turbocharger of an internal combustion engine, is set such that a lower limit (TSQ_dyn_min) of a range of settable values of the turbine flow cross-section is determined as a function of an operating parameter of the internal combustion engine in non-stationary operating states. A speed of the internal combustion engine can be used as the operating parameter.
1. A method for setting an internal combustion engine turbocharger turbine flow cross-section, which comprises the step of:
predetermining a function of a gasoline powered internal combustion engine speed operating parameter so that an internal combustion engine scavenging gradient does not exceed a predetermined maximum value;
detecting the gasoline powered internal combustion engine speed operating parameter;
determining a lower limit of a range of settable values of the turbine flow cross-section as the function of the gasoline powered internal combustion engine speed operating parameter in non-stationary internal combustion engine operating states; and
adjusting an actuator of a turbine geometry for setting an internal combustion engine turbocharger turbine flow cross section for optimizing a torque increase.
2. The method according to claim 1 , wherein the lower limit is additionally determined as a function of another internal combustion engine operating parameter that varies with internal combustion engine load.
3. The method according to claim 2 , wherein the another internal combustion engine operating parameter is a measure of an injected fuel quantity or a combustion chamber charge with air or a fuel/air mixture.
4. The method according to claim 1 , wherein a base value for the turbine flow cross-section to be set is calculated by a boost pressure regulator and an actual turbine flow cross-section to be set is determined by a selection of the maximum of the base value and the lower limit.
5. The method according to claim 4 , wherein the lower limit is additionally determined as a function of another internal combustion engine operating parameter that varies with internal combustion load.
6. The method according to claim 5 , wherein the another internal combustion engine operating parameter is a measure of an injected fuel quantity or a combustion chamber charge with air or a fuel/air mixture.
7. The method according to claim 1 , wherein at least one of a driver command, a boost pressure setpoint value, a boost pressure actual value and the internal combustion engine speed are monitored for changes and an operating state is considered non-stationary when a change velocity of at least one of the monitored values exceeds a predefined threshold value.
8. The method according to claim 7 , wherein the lower limit is additionally determined as a function of another internal combustion engine operating parameter that varies with internal combustion engine load.
9. The method according to claim 8 , wherein the another internal combustion engine operating parameter is a measure of an injected fuel quantity or a combustion chamber charge with air or a fuel/air mixture.
10. The method according to claim 7 , wherein a base value for the turbine flow cross-section to be set is calculated by a boost pressure regulator and an actual turbine flow cross-section to be set is determined by a selection of the maximum of the base value and the lower limit.