Method and Device for Operating an Internal Combustion Engine

摘要

An internal combustion engine has a plurality of cylinders with fuel-metering injection valves, and an exhaust gas probe that generates a measurement signal characteristic of the air/fuel ratio in the respective cylinder. A correction signal for fuel mass to be metered is determined using a lambda controller as a function of the exhaust gas probe measurement signal. When at least one predefined condition is met within a predefined operating range of the engine, a cylinder-specific diagnosis relating to the emissions of pollutants is performed on the basis of unsmooth running, wherein the cylinder-specific diagnosis is actively performed only in a respective detection phase that is applied to a neutral value by a modified proportional discrete level of the correction signal and is performed with a modified integral parameter of the lambda controller that is reduced as compared with an integral parameter in a normal operating mode of the lambda controller.

主权项

1. A method for operating an internal combustion engine having a plurality of cylinders, which are each assigned respective injection valves for metering fuel, and an exhaust gas probe which has discrete level probe characteristics and is arranged in an exhaust gas section and whose measurement signal is characteristic of the an air/fuel ratio in the respective cylinder, a crankshaft angle sensor whose measurement signal is representative of a crankshaft angle of a crankshaft, the method comprising:
determining a correction signal for a fuel mass to be metered using a lambda controller, e.g., as a function of the measurement signal of the exhaust gas probe, when at least one predefined condition is satisfied within a predefined operating range of the internal combustion engine, performing a cylinder-specific diagnosis with respect to emissions of pollutants on the basis of unsmooth running, wherein during the execution of the cylinder-specific diagnosis, the diagnosis actively performed only in a respective detection phase initiated by a modified proportional jump of the correction signal to a neutral value, and wherein the diagnosis is performed with a modified integral parameter of the lambda controller, which integral parameter is reduced in absolute value compared to an integral parameter in a normal operating mode of the lambda controller.