| 摘要 |
The present invention relates to an SCR system and a control method thereof, capable of recirculating exhaust gas, emitted form an SCR reactor, and making the gas used for urea hydrolysis. To this end, the present invention comprises: an SCR reactor including an SCR catalyst removing a harmful component from exhaust gas emitted through a turbo charger (T/C); a recirculation line recirculating the exhaust gas, emitted from the SCR reactor, into the SCR reactor; a heating device heating the exhaust gas recirculated into the SCR reactor; a urea spray device spraying urea into the recirculation line; and a control part recirculating the exhaust gas, emitted from the SCR reactor, into the SCR reactor through the recirculation line, and operating the heating device and the urea spray device. Therefore, the present invention is capable of simplifying a structure by performing urea hydrolysis without an extra hydrolysis chamber, and minimizing the fuel consumption of the heating device by exchanging heat between the recirculated exhaust gas and combustion air, injected into the heating device, while quickly controlling (cooling) the temperature of the recirculation line into a suitable temperature for urea hydrolysis through the temperature of the exhaust gas lowered due to the heat exchange. |
