Patent ID: 7431025

Claim:
A device to operate an internal combustion engine, wherein the internal combustion engine has a cylinder, and an exhaust gas tract with an exhaust gas catalytic converter, a first exhaust gas probe arranged upstream of the exhaust gas catalytic converter and a second exhaust gas probe arranged downstream of the exhaust gas catalytic converter, comprising: a lambda controller to determine a lambda correction factor based upon a first measurement signal assigned to the first exhaust gas probe; a trim controller to determine a proportionate corrective factor, wherein a setpoint value and an actual value of a second measurement signal assigned to the second exhaust gas probe are provided as a control difference for the trim controller; and a control signal unit to determine a control signal for apportioning fuel into the cylinder based upon the lambda correction factor and to determine the control signal also based upon the proportionate corrective factor in a diagnostic operating state of a component assigned to the exhaust gas tract.