Patent ID: 8516801

Claim:
An exhaust gas purifying apparatus for an internal combustion engine, the apparatus comprising: a main exhaust passage through which exhaust gas exhausted from the internal combustion engine flows; a bypass passage branching off from the main exhaust passage at an upstream connecting portion connected to the main exhaust passage while merging again with the main exhaust passage at a downstream connecting portion provided downstream of the upstream connecting portion; flow path switching means that is capable of switching a flow target into which the exhaust gas flows between the main exhaust passage and the bypass passage; an adsorbent that is disposed in the bypass passage and has a function of adsorbing at least NOx of unpurified components contained in the exhaust gas; a catalyst that is disposed in the main exhaust passage and capable of purifying the exhaust gas; a purge passage branching off from the bypass passage while connecting to an intake passage of the internal combustion engine; and an electronic control unit programmed to execute an intake purge operation for controlling the flow path switching means so that part of the exhaust gas exhausted from the internal combustion engine is supplied from the main exhaust passage to the bypass passage and then passes through the adsorbent and then flows back into the intake passage via the purge passage; an exhaust purge operation for controlling the flow path switching means so that part or all of the exhaust gas exhausted from the internal combustion engine is supplied from the main exhaust passage to the bypass passage and then passes through the catalyst after passing through the adsorbent; and a purging switching operation for switching the intake purge operation to the exhaust purge operation after a point in time when a significant desorption of NOx from the adsorbent is completed.