Patent ID: 6497094
Filing Date: 2002-12-24
Classification: F01N,Y02T

Abstract:
A method for monitoring a secondary air system in combination with the exhaust-gas system of a motor vehicle, the method comprising 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 (&lgr;exhaust gas) utilizing said 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 (&lgr;engine), which is metered per unit of time; (b) said air/fuel ratio (&lgr;exhaust gas) obtained from said probe; (c) said signal for the intake air flow (massintake air); and, (d) in accordance with the following equation: &lgr;exhaust gas=&lgr;engine*(1+(masssecondary air/massintake air)); evaluating the operability of said secondary air system in dependence upon said secondary air mass (masssecondary air); determining said secondary air mass (masssecondary air) during the secondary air phase; and, determining the secondary air actual mass (masssecondary air actual) in dependence upon an actuating quantity (FRm) of a &lgr;-controller.