Exhaust purification device for hybrid electric vehicle

An exhaust purification device for a hybrid electric vehicle, in which a generator is driven by using power from an engine which is not used for moving the vehicle, electric power generated by the generator is stored in a battery, and an electric motor that is driven by the electric power supplied from the battery is used as a power source for moving the vehicle, comprising:

• an ammonia selective reduction-type NOx catalyst interposed in an exhaust passage of the engine, for selectively reducing NOx contained in exhaust gas by using ammonia as a reducing agent;
• a urea water supply unit for supplying urea water into the exhaust gas existing upstream of the ammonia selective reduction-type NOx catalyst;
• and
• a control unit for starting or stopping the engine in accordance with a storage state of the battery and controlling the urea water supply unit in accordance with an operating state of the engine, wherein
• when the engine in operation is to be stopped, the control unit stops the engine after executing, over a predetermined period prior to stoppage of the engine, an adsorption increasing operation in which an amount of ammonia adsorbed by the ammonia selective reduction-type NOx catalyst is increased, compared with that before the predetermined period.