Patent ID: 8307633
Filing Date: 2012-11-13
Classification: F01N,Y02T

Abstract:
1. An exhaust gas purification apparatus for an internal combustion engine, the apparatus comprising: a NOx (nitrous oxides) catalyst device installed in an exhaust passage of said internal combustion engine for deoxidizing NOx contained in an exhaust gas, a catalyst regeneration apparatus, control circuitry for controlling said catalyst regeneration apparatus to execute regeneration of said NOx catalyst device from sulfur poisoning by reducing an A/F (air-to-fuel) ratio of said exhaust gas to value that is lower than a stoichiometric A/F ratio, an upstream A/F ratio sensor for obtaining measured values of A/F ratio of said exhaust gas, disposed in said exhaust gas passage at a location which is upstream from said NOx catalyst device, with respect to a flow direction of said exhaust gas, a downstream A/F ratio sensor for obtaining measured values of A/F ratio of said exhaust gas, disposed in said exhaust gas passage at a location which is downstream from said NOx catalyst device, a flow rate sensor for detecting a flow rate of said exhaust gas through said exhaust gas passage, and a temperature sensor for detecting a temperature of said NOx catalyst device; wherein said control circuitry is configured to operate during execution of said regeneration to: wherein said control circuitry is configured to: