| 摘要 |
<P>PROBLEM TO BE SOLVED: To avoid deterioration of emission during sulfur recovery for a NSR catalyst. <P>SOLUTION: An engine system 10 includes an oxidation catalyst 216 and the NSR catalyst 217 in an exhaust pipe 212. An ECU 100 executes basic control. In the case where a sulfur poisoning amount Scco of the oxidation catalyst 216 is equal to or larger than a threshold value Scco1 when the sulfur recovery of the NSR catalyst 217 is demanded, the ECU 100 executes sulfur restraint control at a restraint temperature TnsrL lower than a predetermined recovery temperature TnsrH prior to the sulfur poisoning recovery control at the predetermined recovery temperature TnsrH. The desorption of sulfur from the NSR catalyst 217 is restrained by the sulfur restraint control and the desorption of sulfur from the oxidation catalyst 216 is dominantly accelerated, the sensitivity of sulfur desorption of the oxidation catalyst 216 being relatively high with respect to the temperature. As a result, when the sulfur poisoning amount Scco of the oxidation catalyst 216 is lowered to a value below a threshold value Scco0, the sulfur recovery control at the recovery temperature TnsrH is started and the sulfur recovery in the NSR catalyst 217 is accelerated. <P>COPYRIGHT: (C)2010,JPO&INPIT |
