To prevent leakage of exhaust gas via a flow passage switching valve 4, by arranging a bypass catalytic converter on the further upstream side for performing exhaust emission control just after cold starting.
The flow passage switching valve 4 is arranged in a confluent part of gathering four upstream side main passages connected with every cylinder as a downstream side main passage. An upstream side bypass passage branches off from the respective upstream side main passages as a bypass passage, and the bypass catalytic converter is interposed in the middle of the downstream side bypass passage. When closing the flow passage switching valve 4, the main flow passage is cut off, and at the same time, the mutual upstream side main passages of the respective cylinders become an uncommunicating state. The flow passage switching valve 4 is constituted so that a pair of rotary shafts 27 attached with a valve element symmetrically rotate, and is simultaneously driven by one actuator via a first link 31, a second link 35 and a third link 36. A connecting pin 37 is regulated so as to linearly move along the symmetrical center line L by a guide wall 41.
COPYRIGHT: (C)2007,JPO&INPIT
AKAHA MOTOHARU
Hiromichi Kobayashi
Tomioka Kiyoshi
Next Patent: CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE