VEHICLE AND SINGLE-CYLINDER FOUR-STROKE ENGINE UNIT

摘要

The objective of the present invention is to provide a vehicle that is equipped with a single-cylinder four-stroke engine unit with which a supporting structure can be simplified, exhaust gas purification performance by means of a catalyst can be improved, and the initial vehicle exhaust purification performance can be maintained for a long time. According to the present invention, an upstream end of a main catalyst (39) for a single combustion chamber is disposed further upstream in the flow direction of an exhaust gas than an upstream end of a muffler (35) for a single combustion chamber. In an exhaust channel from one combustion chamber (29) to an emission port (35e), the main catalyst (39) for a single combustion chamber purifies, to the greatest extent, the exhaust gas discharged from the one combustion chamber (29). An upstream oxygen detection member (36) for a single combustion chamber is disposed further upstream than the main catalyst (39) for a single combustion chamber. A downstream oxygen detection member (37) for a single combustion chamber is disposed further downstream than the main catalyst (39) for a single combustion chamber.