EXHAUST GAS CONTROL APPARATUS

摘要

This apparatus includes a control device executing a urea adding valve operation control. The control device calculates a target instantaneous supply amount (QC), which is a urea water supply amount for cooling a urea adding valve, based on an engine operation state. The control device considers a target cooling supply amount (TQc), which is a target urea water supply amount for the cooling of the urea adding valve, as an amount obtained by a part of a difference between a previous target cooling supply amount (TQc[i]) and the target instantaneous supply amount (QC) being added to the previous target cooling supply amount (TQc[i]). When a cooling water temperature (THW) is equal to or higher than a predetermined temperature and the previous target cooling supply amount (TQc[i]) is "0", the control device uses the target instantaneous supply amount (QC) as the previous target cooling supply amount (TQc[i]) as it is.