| 摘要 |
An engine is provided with: a urea water supply mechanism that adds ammonia-derived urea water into an exhaust passage; an SCR catalyst that purifies exhaust gas by adding the urea water; an ammonia oxidation catalyst that is provided on a downstream side of the SCR catalyst in the exhaust passage; and a control unit that controls a urea water additive amount by the urea water supply mechanism. Compared to when a temperature of the ammonia oxidation catalyst is lower than a predetermined temperature, when the temperature of the ammonia oxidation catalyst is equal to or higher than the predetermined temperature, the control unit carries out an additive amount reduction process to reduce the urea water additive amount. |
