| 摘要 |
<p>PURPOSE: To invariably keep the purification factor of NOx constant by controlling the temperature of the exhaust gas of an exhaust pipe section and the opening of the cooling water quantity adjusting valve of the cooling water system of a heat exchanger in an exhaust pipe when the NOx in the exhaust gas is reduced and purified via a catalyst with a fuel such as kerosene used as a reducing agent. CONSTITUTION: A heat exchanger (cooler) 14 for cooling the exhaust gas 16 is provided on the exhaust pipe 12 of a diesel engine 10, and cooling water 15 is fed to the cooler 14 via an inlet pipe 14 provided with a cooling water quantity adjusting valve 34. A fuel adding nozzle 18 is fitted to the exhaust pipe 12 on the upstream side of the cooler 14, and a fuel such as kerosene is injected and added to the exhaust gas 16 flowing in the exhaust pipe 12 to reduce and purify NOx. A controller 30 receives the detection signals of the first and second temperature sensors 40, 28 monitoring the temperature of the cooled exhaust gas 16 and the temperature of a catalyst layer 26, controls the opening of the cooling water quantity adjusting valve 34, and controls the exhaust gas 16 at the prescribed 1 temperature.</p> |
