Method for diagnosing operation of precatalyst probe, in exhaust gas system of motor vehicle, involves triggering change of fat exhaust gas to lean exhaust gas or lean exhaust gas to fat exhaust gas, partially independent from lapse of time

摘要

The method involves arranging a lambda probe (6) in an exhaust gas system (2) in outflow direction of exhaust gas, which emerges from an internal combustion engine (1), behind a section of a catalyst (3) with oxygen storage capacity. A change of a fat exhaust gas to a lean exhaust gas or change of the lean exhaust gas to the fat exhaust gas is effected, and a signal recorded by the probe is used for diagnosing during the change. The change is triggered by an event partially independent from lapse of time, and a time interval is defined in dependence of time point of the change.