Patent ID: 8315782

Claim:
A method of operating an internal combustion engine comprising an exhaust gas tract, which has a first catalytic exhaust converter and a second catalytic exhaust converter disposed downstream of the first, a first exhaust gas sensor, which is disposed upstream of, or in, the first catalytic exhaust converter, and a second exhaust gas sensor, which is disposed downstream of the first catalytic exhaust converter and upstream of the second catalytic exhaust converter, the method comprising: during an overrun phase of the internal combustion engine: monitoring the measuring signal of the second exhaust gas sensor; based on the monitored measuring signal of the second exhaust gas sensor, identifying a signal characteristic that indicates a maximum degree of charging of the first catalytic exhaust converter with oxygen, and in response to the identification of the signal characteristic indicating a maximum degree of charging of the first catalytic exhaust converter with oxygen, determining a characteristic variable of a degree of charging of the second catalytic exhaust converter with oxygen as a function of an operating variable of the internal combustion engine, and outside of the overrun phase, controlling an enrichment phase by enriching an air-fuel mixture supplied to the internal combustion engine as a function of the characteristic variable of the degree of charging of the second catalytic exhaust converter with oxygen determined during the overrun phase.