EXHAUST GAS CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINE

In an exhaust gas control system for an internal combustion engine operable at a lean air-fuel ratio, after a request to stop the internal combustion engine has been issued, the internal combustion engine is operated at a stoichiometric air-fuel ratio or lower until an air-fuel ratio in an SCR catalyst becomes lower than or equal to the stoichiometric air-fuel ratio, and then supply of fuel to the internal combustion engine is stopped.