Patent ID: 8181447

Claim:
An exhaust gas purification device having a catalyst provided in an exhaust path of an internal combustion engine and a fuel addition valve adding fuel to said exhaust path, comprising: an electronic control unit which estimates an exhaust gas temperature to be exhausted to said exhaust path, using an atmospheric pressure as a parameter, wherein the electronic control unit sets a basic addition amount of the fuel to be added to said exhaust path, wherein the electronic control unit corrects an addition amount of the fuel to be added to said exhaust path to increase said addition amount of the fuel with an increase in an amount of change in the exhaust gas temperature obtained by subtracting a basic exhaust gas temperature obtained upon said basic addition amount being set from an exhaust gas temperature at present estimated by the electronic control unit, and wherein the electronic control unit corrects an injection amount of the fuel to be injected to said exhaust path by multiplying at least one of a basic addition time interval and a basic addition time period by a correction coefficient according to said amount of change in the exhaust gas temperature.