EXHAUST TREATMENT METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

A method according to the present invention supplies fuel to an exhaust passage (17a) that is farther upstream than an exhaust turbine (25b) of an exhaust turbine supercharger (25), and ignites and burns the fuel so as to heat exhaust guided from an engine (10) to an exhaust purification device (26). The method has a step for extinguishing the ignited flames before the flames reach the exhaust turbine (25b) of the exhaust turbine supercharger (25), by increasing the rotation speed of the exhaust turbine (25b), and controlling the amount of fuel supplied to the exhaust passage (17a) so that the air-fuel ratio of the exhaust flowing into the exhaust turbine (25b) is stoichiometric or slightly lean. According to the present invention, it is possible to suppress a reduction in the thermal durability of the exhaust turbine (25b) caused by the flames generated from burning the fuel supplied to the exhaust passage (17a).