EXHAUST EMISSION CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device that causes residual fuel to be discharged by introducing air to an addition valve and enables suppression of occurrence of wear on an inner surface of a valve body and an outer surface of a needle.SOLUTION: An air passage 8 connected to an intake passage 4 of an engine 1 includes an air pump 81 and an air tank 82. A selector valve 83 is provided at a connecting position between the air passage 8 and an addition fuel passage 51. After a fuel addition operation of a fuel addition valve 5 is completed, the selector valve 83 is switched to communicate the air passage 8 and a downstream side passage 51b of the addition fuel passage 51 with each other, and air is introduced to the fuel addition valve 5 so as to discharge residual fuel of the fuel addition valve 5. This residual fuel discharge operation is executed only for a preset predetermined period enabling the overall amount of fuel remaining in a nozzle hole to be discharged while maintaining lubrication performance of a sliding contact portion between a valve body of the fuel addition valve 5 and a needle. This inhibits occurrence of wear on the inner surface of the valve body and the outer surface of the needle.SELECTED DRAWING: Figure 1