Apparatus for controlling exhaust gas in internal combustion engine

摘要

The present invention relates to an apparatus for controlling exhaust noise in an internal combustion engine by using the length difference between the exhaust pipe (60) and the bypass pipe (70). The apparatus comprises an exhaust pipe (60) for outwardly releasing exhaust gas from the engine (50); a bypass pipe (70) variable in length which diverges from said exhaust pipe with a distance and has U-shaped and reverse U-shaped sections formed alternately; an actuator (80) having an actuating rod (81) connected to said bypass pipe to vary the length of said bypass pipe; and a control unit (90) for controlling said actuator. The bypass pipe has the U-shaped and reverse U-shaped sections arranged alternately so that the variable length of the bypass pipe can be extended while minimizing the space for installing the bypass pipe, and thereby noise in the low frequency band can be suitably reduced. Also, the exhaust pipe is additionally provided with the means for adjusting the length to increase the length difference with the bypass pipe so that noise in a wider band can be controlled.