Method for injection duration correction in an internal combustion engine having a secondary-air system
First Claim
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1. A method for injection duration correction in an internal combustion engine, which comprises:
- blowing secondary air into an exhaust tract upstream of a catalyst via a secondary-air system during a warm-up phase of an internal combustion engine;
detecting a main-air mass flow present in an intake tract of the internal combustion engine and a secondary-air mass flow provided by the secondary-air system;
carrying out an injection duration correction in dependence on the main-air mass flow, the secondary-air mass flow and a pilot control value for an air/fuel ratio;
deducing a presence of a transient mode of the internal combustion engine from values of the main-air mass flow;
correcting the secondary-air mass flow in the transient mode of the internal combustion engine, and calculating a deviation between a desired value, determined from a model for the secondary-air mass flow, and a detected actual value of the secondary-air mass flow; and
determining a correction factor for the injection duration correction from a correction value for the secondary-air mass flow, the main-air mass flow and the pilot control value for the air/fuel ratio.
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Abstract
By taking into account the deviation between a desired value, determined from a model for a secondary-air mass flow and an actual value of the secondary-air mass flow, detected by an airflow sensor, a correction value is obtained. From the correction value, together with a main-air mass flow that is present in an intake tract of the internal combustion engine and a pilot control value for an air/fuel ratio, a correction factor for correcting an injection duration is derived.
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6 Claims
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1. A method for injection duration correction in an internal combustion engine, which comprises:
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blowing secondary air into an exhaust tract upstream of a catalyst via a secondary-air system during a warm-up phase of an internal combustion engine; detecting a main-air mass flow present in an intake tract of the internal combustion engine and a secondary-air mass flow provided by the secondary-air system; carrying out an injection duration correction in dependence on the main-air mass flow, the secondary-air mass flow and a pilot control value for an air/fuel ratio; deducing a presence of a transient mode of the internal combustion engine from values of the main-air mass flow; correcting the secondary-air mass flow in the transient mode of the internal combustion engine, and calculating a deviation between a desired value, determined from a model for the secondary-air mass flow, and a detected actual value of the secondary-air mass flow; and determining a correction factor for the injection duration correction from a correction value for the secondary-air mass flow, the main-air mass flow and the pilot control value for the air/fuel ratio. - View Dependent Claims (2, 3, 4, 5, 6)
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