EXHAUST GAS PURIFICATION APPARATUS

摘要

The exhaust gas purification apparatus 100 according to the present invention is provided with an exhaust gas purification catalyst 40, an upstream O2 sensor 14, a downstream O2 sensor 15, and a control section 30 that executes main F/B control and sub-F/B control. This exhaust gas purification apparatus 100 contains, on a support in a prescribed region 45 from a catalyst-outlet-side end 43a at the downstream side of an exhaust gas purification catalyst 40, an OSC material having a pyrochlore structure and an OSC material having an oxygen storage rate that is faster than that of the OSC material having a pyrochlore structure.

主权项

1. An exhaust gas purification apparatus that is disposed in an exhaust system of an internal combustion engine and that purifies an exhaust gas, the exhaust gas purification apparatus comprising:
an exhaust gas purification catalyst that is disposed in the exhaust system and that has a catalyst layer formed on a substrate and including a support containing an OSC material having an oxygen storage capacity and a precious metal catalyst supported on this support; an upstream O2 sensor that is disposed in the exhaust system upstream from the exhaust gas purification catalyst and that detects an upstream O2 concentration, which is an oxygen concentration in the exhaust gas on the upstream side of the exhaust gas purification catalyst; a downstream O2 sensor that is disposed in the exhaust system downstream from the exhaust gas purification catalyst and that detects a downstream O2 concentration, which is an oxygen concentration in the exhaust gas on the downstream side of the exhaust gas purification catalyst; and a control section that is configured to be capable of executing main feedback control that calculates an air/fuel ratio for an air-fuel mixture being supplied to the internal combustion engine based on the upstream O2 concentration and that sets a first control target value based on the calculated air/fuel ratio and a predetermined target air/fuel ratio, sub-feedback control that sets a second control target value by correcting the first control target value based on the downstream O2 concentration, and air/fuel ratio adjustment control that adjusts the air/fuel ratio of the air-fuel mixture supplied to the internal combustion engine based on the second control target value, wherein the support in a prescribed region from a catalyst-outlet-side end at the downstream side of the exhaust gas purification catalyst contains an OSC material having a pyrochlore structure and an OSC material having an oxygen storage rate that is faster than that of the OSC material having a pyrochlore structure.