One kind of urea injection control method and the control unit

The present invention discloses a method for controlling urea injection and control unit, the urea injection control method and a control unit searching for a corresponding theoretical target amount of urea injection from said first predetermined correspondence relationship according to a predetermined target injection amount of urea theory received first correction factor; then, the predetermined theoretical target amount of urea injection from the first correction factor multiplied by the correction injection amount of urea; Finally, according to the correction amount controlling urea injection of urea injection. Since the first correction factor and correction of the deviation factor due to the injection mechanism system, systematic errors caused by the actual injection quantity and the theoretical target injection quantity injected from the urea injection system caused, therefore, the correction injection amount of urea injection system mechanism due consideration factors affecting the system error to the injection amount of urea, a urea injection system so that when the urea injection amount to the correction amount of urea outwardly, the actual amount of urea injected is consistent with theoretical target amount of urea injection.