Diagnosis method and device for operating an internal combustion engine

摘要

A method is disclosed for performing an individual cylinder diagnosis with respect to pollutant emissions within a predefined operating range of an internal combustion engine, meeting at least one predefined condition. During the performing of the individual cylinder diagnosis, a forced activation, by means of which a predefined air/fuel ratio to be set is activated, is prescribed in a manner synchronous to the cylinder segment. The excitation is carried out such that each individual cylinder is subjected during subsequent working cycles to a mixture that is either richer or leaner in comparison to the predefined air/fuel ratio to be set due to the forced excitation. Depending on the forcibly activated air/fuel ratio to be set, the corresponding injection valves are actuated.

主权项

1. A method for operating an internal combustion engine including multiple cylinders corresponding to respective injection valves for the metering of fuel, an exhaust-gas probe arranged in an exhaust tract and configured to generate a measurement signal representative of an air/fuel ratio in a respective cylinder, and a crankshaft angle sensor configured to generate a measurement signal representative of a crankshaft angle of a crankshaft, the method comprising:
within a predefined operating range of the internal combustion engine, when at least one predefined condition is met, performing a cylinder-specific diagnosis with regard to pollutant emissions, during the cylinder-specific diagnosis, defining in a cylinder-segment-synchronous manner a forced inducement configured to induce a predefined air/fuel ratio to be set, and during successive working cycles:
charging each respective individual cylinder with a mixture that is either enriched or leaned by the defined forced inducement in relation to the predefined air/fuel ratio to be set, andactuating each respective injection valve as a function of the forcibly induced air/fuel ratio to be set.