| 摘要 |
A dual NOx trap system for reducing NOx emissions from an internal combustion engine. The system is plumbed and controlled such that the NOx adsorption time of a trap is decoupled from the NOx regeneration time. A trap is taken out of service for regeneration only for the minimum required regeneration time and then is placed back into service. Because regeneration times are short relative to adsorption times, during most of the working life of the assembly both of the traps are in service in NOx-trapping mode. Thus, higher NOx-trapping efficiencies are provided over most of the working life of the system because each unit volume of catalyst is in service for more than 50% of the time, permitting a smaller volume of catalyst for each trap than in a prior art system. Further, shorter off-line regeneration times result in reduced cooling of the traps during regeneration.
|
