| 摘要 |
PROBLEM TO BE SOLVED: To prevent excessive supply of aqueous urea and cooling water to a carburetor. SOLUTION: A NOx removal reactor 11 and an internal combustion engine 12 are connected by an exhaust gas pipe 14. The carburetor 18 arranged the exhaust gas pipe 14 adds a reducing agent to exhaust gas G and aqueous as a reducing agent is supplied from an aqueous urea tank 19 via a liquid delivery pipe 20. A solenoid valve 21 for main valve, a solenoid valve 22 for regulating flow rate, a pump 23 and an aqueous urea flow meter 24 are successively interposed in the liquid delivery pipe 20. The carburetor 18 is provided with a water pipe 25 for supplying cooling water to cool the carburetor 18. In the water pipe 25, a solenoid valve 26 for main valve, a solenoid valve 27 for regulating flow rate and a cooling water flow meter 28 are successively interposed. A solenoid valve 29 for bypass communicates the liquid delivery pipe 20 with the water pipe 25. Each of the solenoid valve 21, 22, 26, 27, 29 is controlled by an operation signal from a program controller 35. |
