Patent ID: 8959897
Filing Date: 2015-02-24
Classification: B01D,F01N,Y02T

Abstract:
1. An exhaust gas purification apparatus in an internal combustion engine comprising: a pre-catalyst that has an oxidation function and is arranged in an exhaust passage of the internal combustion engine in such a manner that an exhaust gas can flow through between an outer peripheral surface thereof and an inner peripheral surface of said exhaust passage; a post-catalyst that has an oxidation function and is arranged in said exhaust passage at a downstream side of said pre-catalyst; a reducing agent addition valve that is arranged at a location immediately upstream of said pre-catalyst in said exhaust passage, and adds, when raising the temperature of said post-catalyst, a reducing agent in such a manner that said reducing agent passes through said pre-catalyst; a retention catalyst that is arranged at a downstream side of said pre-catalyst and at an upstream side of said post-catalyst in said exhaust passage, and has a function to temporarily retain said reducing agent in said exhaust gas; and an electronic control unit including a routine for exhaust gas purification control, the routine, when executed by the electronic control unit, performing the steps of: