Abstract: In a method for reducing particulate emissions of an internal combustion engine during a cold start of the internal combustion engine, the combustion chamber temperature and the ambient temperature are determined. A cold start condition is recognized when the combustion chamber temperature is below a first threshold temperature and the ambient temperature is below a second threshold temperature. In this case, the internal combustion engine is dragged by means of the starter, wherein air that is present in the combustion chambers is compressed and heated. This heat is discharged to the combustion chamber walls, which are likewise heated up. In this operating situation there is no fuel injection in the combustion chambers and no ignition, so that no combustion takes place in the combustion chambers and the internal combustion engine compresses solely fresh air. The combustion chambers heat up due to the compression work, thus achieving better evaporation of the fuel in the combustion chamber.

Abstract: In a method for the regeneration of a particulate filter or of a four-way catalytic converter in an exhaust system of an internal combustion engine, an increase in the nitrogen oxide emissions during the regeneration of the particulate filter or of the four-way catalytic converter can be prevented or at least reduced. A particulate filter or a four-way catalytic converter is arranged in the exhaust system of an internal combustion engine. The fuel injection and the ignition are switched off in response to a request for the internal combustion engine to be turned off. Due to mass inertia, the internal combustion engine transitions from the switch-off rotational speed to a standstill whereby, during this phase, oxygen-rich air is conveyed into the exhaust passage.

Abstract: A method for checking a load condition of a particulate filter in an exhaust line of an internal combustion engine, wherein the exhaust line comprises at least the particulate filter, a first lambda sensor that is arranged upstream from the particulate filter, and a second lambda sensor that is arranged downstream from the particulate filter, includes at least the following steps: introducing an exhaust gas with an excess of oxygen into the exhaust line upstream from the first lambda sensor, there being a temperature of at least 500° C. in the particulate filter; detecting the excess of oxygen by the first lambda sensor at a first time; detecting the excess of oxygen by the second lambda sensor at a second time; and determining a load condition of the particulate filter from a time difference between the first time and the second time. The invention further relates to an exhaust system of a motor vehicle.

Abstract: In a method for reducing particulate emissions of an internal combustion engine during a cold start of the internal combustion engine, the combustion chamber temperature and the ambient temperature are determined. A cold start condition is recognized when the combustion chamber temperature is below a first threshold temperature and the ambient temperature is below a second threshold temperature. In this case, the internal combustion engine is dragged by means of the starter, wherein air that is present in the combustion chambers is compressed and heated. This heat is discharged to the combustion chamber walls, which are likewise heated up. In this operating situation there is no fuel injection in the combustion chambers and no ignition, so that no combustion takes place in the combustion chambers and the internal combustion engine compresses solely fresh air. The combustion chambers heat up due to the compression work, thus achieving better evaporation of the fuel in the combustion chamber.

Abstract: A method for regenerating a particulate filter in an exhaust system of an internal combustion engine. In a normal operation, the internal combustion engine is operated at a stoichiometric air/fuel ratio. To regenerate the particulate filter, it is provided that the air/fuel ratio be adjusted toward lean, and, at the same time, that the combustion in the combustion chambers of the internal combustion engine be stabilized by suitably adapting the ignition energy, the duration of ignition, and/or the ignition frequency, to prevent misfires and the associated uncontrolled entrainment of unburned fuel into the exhaust system. The inventive method for regenerating the particulate filter makes possible a more rapid and lower-emission regeneration of a particulate filter. Also, an internal combustion engine having an exhaust system and a control unit that is adapted for implementing a method according to the present invention.

Abstract: In a method for the regeneration of a particulate filter or of a four-way catalytic converter in an exhaust system of an internal combustion engine, an increase in the nitrogen oxide emissions during the regeneration of the particulate filter or of the four-way catalytic converter can be prevented or at least reduced. A particulate filter or a four-way catalytic converter is arranged in the exhaust system of an internal combustion engine. The fuel injection and the ignition are switched off in response to a request for the internal combustion engine to be turned off. Due to mass inertia, the internal combustion engine transitions from the switch-off rotational speed to a standstill whereby, during this phase, oxygen-rich air is conveyed into the exhaust passage.