Exhaust gas cleaning system for internal combustion engine capable of lean running, has master and secondary storage devices for nitrogen oxides that can be operated in nitrogen oxides storage phase(s) and nitrogen oxides regeneration phase

摘要

Exhaust gas cleaning system for an internal combustion engine capable of lean running, comprises a master and a secondary storage devices for nitrogen oxides, which can be operated in nitrogen oxides storage phase(s) and nitrogen oxides regeneration phase. The secondary storage device assumes a 3-way catalytic converter function during a nitrogen oxides regeneration phase of the master storage device. Exhaust gas cleaning system for an internal combustion engine capable of lean running, comprises a master and a secondary storage devices for nitrogen oxides. The secondary storage device (4) is disposed in an exhaust gas train of the internal combustion engine downstream of the master storage device (3). The storage devices can be operated in NOx storage phase(s) and one NOx regeneration phase. The secondary storage device is formed and intended to store at least a portion of the NOx mass of the characteristic NOx desorption peak at the beginning of an NOx regeneration phase of the master storage device; converts the reducing agent mass of the characteristic escape of reducing agent in an oxidative manner after termination of the NOx regeneration phase using the stored NOx mass; and assumes a 3-way catalytic converter function during an NOx regeneration phase of the master storage device. Independent claims are also included for: (1) method of operating an exhaust gas cleaning system for an internal combustion engine as above, comprising storing at least a portion of the NOx mass of the characteristic NOx desorption peak at the beginning of an NOx regeneration phase of the master storage device; and converting the reducing agent mass of a characteristic escape of reducing agent in an oxidative manner after termination of the NOx regeneration phase using the stored NOx mass on the secondary storage device; and (2) method of desulfurizing an exhaust gas cleaning system for an internal combustion engine as above, comprising charging secondary storage device with oxygen to ensure conversion of hydrogen sulfide emissions and/or carbonyl sulfide emissions in the exhaust gas downstream of the master storage device at least during the desulfurization time interval, in order to desulfurize the master storage device a minimum temperature of the master storage device and a rich phase of the exhaust gas are set for a desulfurization time interval.