STRADDLE RIDING-TYPE VEHICLE

摘要

A straddle riding-type vehicle having an internal combustion engine where combustion is taken place at an air-fuel ratio less than a theoretical air-fuel ratio, wherein the purification ratio of NOx is improved. A straddle riding-type vehicle has an internal combustion engine performing combustion at an air-fuel ratio less than a theoretical air-fuel ratio, a first catalyst provided in an exhaust route for discharging combustion gas from the engine, a second catalyst provided at that portion of the exhaust route which is downstream of the first catalyst, and a secondary-air introduction device for introducing secondary air into that portion of the exhaust route which is between the first and second catalysts. The first and second catalysts each contain a precious metal component including at least one of Pt, Rh, Pd, and Au. The first catalyst further contains an ammonia decomposing catalyst.