EXHAUST EMISSION CONTROL DEVICE OF DIESEL ENGINE

摘要

PROBLEM TO BE SOLVED: To reduce NOx in exhaust gas properly by supplying hydrocarbon fuel to a NOx catalyst through a reformed catalyst, and supplying the reformed catalyst with air enough for combustion by the reformed catalyst. SOLUTION: A NOx catalyst 2 for purifying NOx in exhaust gas is arranged on the pipe expanding part 1a of an exhaust passage 1. Before fuel is supplied to the NOx catalyst 2, a reformed catalyst 3 for reducing the number of carbon is arranged on the exhaust downstream side of the penetrating hole 2a of the NOx catalyst 2. A plate member 4 is arranged on the exhaust downstream side end surface of the reformed catalyst 3. The penetrating hole 2a of the NOx catalyst 2 is closed by the plate member 4, and exhaust gas does not flow into the informed catalyst 3 since exhaust gas is not passed the penetrating hole 2a. A supplying pipe 5 is connected to the plate member 4. The supplying pipe 5 is branched into two branches, one is connected to a fuel pump for controlling a light oil supplying rate, and the other one is connected to an air pump for controlling an air supplying rate. It is thus possible to realize good reducing of NOx without wasting new much energy.