A method is described for regulating a filling of an exhaust gas component storage of a catalytic converter in the exhaust gas of an internal combustion engine, in which an actual fill level of the exhaust gas component storage is ascertained using a first system model, and in which a base lambda setpoint value for a first control loop is predefined by a second control loop. The method is distinguished by the fact that in the second control loop an initial value for the base lambda setpoint value is converted into a fictitious fill level via a system model identical to the first system model, the fictitious fill level being compared with a setpoint value for the fill level output by a setpoint value generator, and the base lambda setpoint value being iteratively changed as a function of the comparison result, if the comparison result indicates a difference between the setpoint value for the fill level and the fictitious fill level, which is greater than a predefined degree, and the base lambda setpoint value not being changed if the comparison result indicates no difference between the setpoint value for the fill level and the fictitious fill level.

A method and system for monitoring an exhaust gas sensor coupled in an engine exhaust is provided. In one example, the method determines an estimate of an exhaust gas oxygen sensor time constant according to a comparison of air/fuel ratios and a system time constant.

An internal combustion engine includes an exhaust purification catalyst. A control system includes an air-fuel ratio sensor downstream of the exhaust purification catalyst, and an air-fuel ratio control device which controls the air-fuel ratio of the exhaust gas. The target air-fuel ratio is set to a lean air-fuel ratio when output air-fuel ratio of the sensor becomes a rich judged air-fuel ratio or less and is set to a rich air-fuel ratio when output air-fuel ratio becomes a lean judged air-fuel ratio or more. When the engine operating state is a steady operation state and is a low load operation state, at least one of an average lean degree of the target air-fuel ratio while the target air-fuel ratio is set to a lean air-fuel ratio and an average rich degree of the target air-fuel ratio while the target air-fuel ratio is set to a rich air-fuel ratio is increased.

A supply system for supplying ozone to an engine includes an electrolysis part that electrolyzes water to generate hydrogen and oxygen, a first supply part that supplies hydrogen generated by the electrolysis part to an intake pipe of the engine, an ozone generation part that generates ozone from oxygen generated by the electrolysis part, and a second supply part that supplies ozone generated by the ozone generation part to the intake pipe.

A method and system for monitoring an exhaust gas sensor coupled in an engine exhaust is provided. In one example, the method determines an estimate of an exhaust gas oxygen sensor time constant according to a comparison of air/fuel ratios and a system time constant.

An internal combustion engine comprises an exhaust purification catalyst. A control system of the engine comprises a downstream side air-fuel ratio sensor at a downstream side of the exhaust purification catalyst, and an air-fuel ratio control device which controls the air-fuel ratio of the exhaust gas. The target air-fuel ratio is set to a lean air-fuel ratio when an output air-fuel ratio of the sensor becomes a rich judged air-fuel ratio or less and is set to a rich air-fuel ratio when an output air-fuel ratio becomes a lean judged air-fuel ratio or more. When the engine operating state is a steady operation state and is a low load operation state, at least one of an average lean degree of the target air-fuel ratio while the target air-fuel ratio is set to a lean air-fuel ratio and an average rich degree of the target air-fuel ratio while the target air-fuel ratio is set to a rich air-fuel ratio is increased.

A supply system for supplying ozone to an engine includes an electrolysis part that electrolyzes water to generate hydrogen and oxygen, a first supply part that supplies hydrogen generated by the electrolysis part to an intake pipe of the engine, an ozone generation part that generates ozone from oxygen generated by the electrolysis part, and a second supply part that supplies ozone generated by the ozone generation part to the intake pipe.

A method for operating an internal combustion engine includes: introducing a fuel gas with a fluctuating hydrogen content into an air path of the internal combustion engine; adjusting a combustion air ratio for a combustion chamber of the internal combustion engine via a predeterminable fuel gas mass flow into the air path; adjusting a power variable of the internal combustion engine by a throttle valve that is arranged in the air path; detecting a nitrogen oxide concentration in an exhaust gas path of the internal combustion engine; adjusting the combustion air ratio depending on the nitrogen oxide concentration that is detected; detecting a throttle valve reserve in the air path; and selecting an ignition timing in the combustion chamber of the internal combustion engine depending on the throttle valve reserve that is detected.