| 摘要 |
<p>The present invention provides an exhaust purification apparatus for an internal combustion engine which enables a decrease in NOx purification rate and possible ammonia slip to be inhibited. The apparatus includes an NOx catalyst (35), a urea aqueous solution addition valve (70) serving as reducing agent adding means, and NOx sensors (90A), (90B) provided an inlet and an outlet of the NOx catalyst (35), respectively. When the bed temperature of the NOx catalyst (35) is in a predetermined high-temperature region in which the amount of ammonia converted into NOx increases relatively and an NOx purification rate decreases relatively, the apparatus uses outputs from the NOx sensors (90A), (90B) to perform correction such that the actual addition amount of the urea aqueous solution addition valve (70) reaches a target addition amount.</p> |
