| 摘要 |
PROBLEM TO BE SOLVED: To provide an internal combustion engine exhaust purification device which can improve a NOx purification rate by injecting urea water solution during fuel cut and curb generation of a deposit in association with injection of the urea solution during the fuel cut as much as possible.SOLUTION: An exhaust purification device comprises: an SCR catalyst, a urea water injector which injects urea water solution into exhaust; an exhaust temperature sensor which acquires a temperature of the exhaust; injection amount control means which controls an injection amount of the urea water solution through the urea water injector; and deposit determination means which determines whether or not an inside of an exhaust pipe is in a state allowing a significant amount of a deposit to be generated when the urea water solution is injected through the urea water injector on the basis of the temperature of the exhaust. The injection amount control means stops injection of the urea water solution when the deposit is determined to be generated or executes the injection of the urea water solution when the same is not determined to be generated during the fuel cut operation.SELECTED DRAWING: Figure 5 |
