SYSTEM FOR INJECTING FUEL INTO EXHAUST PIPE

摘要

Provided is a system for injecting fuel into an exhaust pipe, which is capable of preventing a fuel content of exhaust gas from burning and depositing on a spray hole at a front end of a fuel injection valve. In a system 5 for injecting fuel into an exhaust pipe, an exhaust pipe 11 is connected to an engine 10 via an exhaust adaptor 50 and the fuel is injected directly into the exhaust pipe 11 through a fuel injection valve 52 provided in the exhaust adaptor 50. A front end 52a of the fuel injection valve 52 is provided in an inner wall of an exhaust path 51 located inside the exhaust adaptor 50. The inner wall provided with the front end 52a of the fuel injection valve 52 protrudes from the exhaust path 51 of the exhaust adaptor 50 in a direction in which the diameter of the inner wall expands. A coolant passage 64 for cooling the periphery of the front end 52a of the fuel injection valve 52 is provided within the exhaust adaptor 50.