Patent ID: 6363771
Filing Date: 2002-04-02
Classification: B01D,F01N,Y02T

Abstract:
An emissions diagnostic system for a compression ignition engine having an exhaust gas stream directed into an SCR catalyst capable of reducing NOx in the exhaust gas stream, the system comprising:a tank for storing a solution of urea; a pump in fluid communication with the tank for drawing the solution of urea from the tank; a valve in fluid communication with the pump and the exhaust gas stream for receiving the solution of urea from the pump; an air pump connected to the valve for providing air into the valve for mixing with the solution of urea, the valve for spraying the solution of urea into the exhaust gas stream; a sensor for sensing the level of NOx emissions emitted by the SCR catalyst; a control module connected to the sensor for determining whether the level of NOx emissions is at an acceptable level; and a sensor associated with the air pump for sensing the air pressure being generated by the air pump, the sensor being connected to the control module for determining whether the sensed pressure is at an acceptable limit.