EXHAUST EMISSION CLEANING DEVICE AND EXHAUST EMISSION CLEANING METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

PPROBLEM TO BE SOLVED: To provide an exhaust emission cleaning device and an exhaust emission cleaning method maintaining low-temperature occlusion capacity when a NOx occlusion catalyst is inactive. PSOLUTION: The NOx occlusion catalyst comprising a noble metal catalyst and a NOx absorbing agent, performing low-temperature occlusion of NOSB2/SBincluded in exhaust gas to the NOx absorbing agent when the NOx occlusion catalyst is inactive, and performing high-temperature occlusion of the low-temperature occluded NOSB2/SBto the NOx absorbing agent after the NOx occlusion catalyst is activated, when an air-fuel ratio of the exhaust gas is lean, is arranged inside an exhaust passage. In this exhaust emission cleaning device and method, by performing NOx occlusion catalyst regeneration control (109, 115), which includes low-temperature occlusion of NOSB2/SBincluded in exhaust gas to the NOx absorbing agent when the catalyst is inactive and activation of the NOx occlusion catalyst at least by increasing the temperature of the NOx occlusion catalyst to predetermined temperature (109) when a predetermined NOx occlusion catalyst regeneration condition is realized (107), the low-temperature occlusion capacity of the NOx absorbing agent when the NOx occlusion catalyst is inactive is regenerated. PCOPYRIGHT: (C)2005,JPO&NCIPI