System for injecting fuel into exhaust pipe

A system for injecting fuel into an exhaust pipe of an engine, comprising:

• an exhaust pipe located at a lower, downstream end of an exhaust adaptor,
• an exhaust path defined by a wall formed in the exhaust adaptor;
• a fuel injection valve provided in a first side of the wall intermediately in a vertical direction of the exhaust adaptor to inject a fuel stream obliquely downward into the exhaust path,
• wherein a second side of the wall is opposite the first side of the wall and includes a portion that has a concave-shaped relative to the fuel injection valve, which portion directly faces the fuel injection valve, and at least part of the fuel from the fuel injection valve is injected directly onto the concave-shaped portion,
• wherein the lower end of the exhaust adaptor has a lower flange part to which a front end flange part of the exhaust pipe is connected;
• and
• a tubular shielding part protruding from the lower end of the exhaust adaptor and into the exhaust pipe for preventing the fuel injected into the exhaust path from falling onto surfaces of the front end flange part and the lower flange part,
• wherein an inner wall part of the shielding part is located closer to a center line of the exhaust pipe than a deepest part of the concave-shaped portion.