Patent ID: 7753039

Claim:
An exhaust gas control apparatus of an internal combustion engine having a first cylinder and a second cylinder, comprising: a first exhaust pipe connected to the first cylinder; a second exhaust pipe connected to the second cylinder; a communicating pipe that connects together an intermediate portion of the first exhaust pipe and an intermediate portion of the second exhaust pipe; an exhaust gas control catalyst arranged in the second exhaust pipe downstream of the intermediate portion to which the communicating pipe is connected; and an exhaust gas amount reducing device which reduces an amount of exhaust gas that flows from the first exhaust pipe into the second exhaust pipe through the communicating pipe during execution of a rich/lean burn control which performs combustion with an air-fuel ratio of an air-fuel mixture that is richer than the stoichiometric air-fuel ratio in one of the first cylinder and second cylinder, and performs combustion with an air-fuel ratio of an air-fuel mixture that is leaner than the stoichiometric air-fuel ratio in the other cylinder.