Monitoring method of secondary air system connected to automobile exhaust gas system

摘要

A method for monitoring a secondary air system in combination with the exhaust-gas system of a motor vehicle is described. The method includes the steps of: providing a probe downstream of the junction of a secondary air line into the exhaust-gas channel; obtaining an air/fuel ratio (lambdexhaust gas) utilizing the probe; obtaining a signal for the intake air flow (massintake air); arithmetically determining the secondary air mass (masssecondary air) in dependence upon (a) the ratio of intake air flow to fuel (lambdengine), which is metered per unit of time; (b) the air/fuel ratio (lambdexhaust gas); and, (c) the signal for the intake air flow (massintake air); and, evaluating the operability of the secondary air system in dependence upon the secondary air mass (masssecondary air).