Patent ID: 8353151

Claim:
An exhaust gas control apparatus for an internal combustion engine, comprising: an exhaust gas processing device that is provided in an engine exhaust passage, and that purifies exhaust gas; a compact oxidation catalyst which is provided in the engine exhaust passage at a position upstream of the exhaust gas processing device, which has a cross section that is smaller than a cross section of the engine exhaust passage, and in which part of the exhaust gas flows; a fuel supply device that supplies fuel toward the compact oxidation catalyst; a heating device that is provided between the compact oxidation catalyst and the fuel supply device and that provides heating; and a control unit that controls the fuel supply device and the heating device, wherein there are a first operation region where it is possible to ignite the fuel when the fuel is supplied into the exhaust gas by the fuel supply device and the fuel is heated by the heating device, and a second operation region where it is not possible to ignite the fuel when the fuel is supplied into the exhaust gas by the fuel supply device and the fuel is heated by the heating device; control modes for the exhaust gas control apparatus include a first control mode where the fuel is supplied from the fuel supply device, the fuel is heated by the heating device, and the fuel is ignited, a second control mode where the fuel is supplied from the fuel supply device, the fuel is heated by the heating device, and the fuel is not ignited, and a third control mode where the fuel is supplied from the fuel supply device and the heating device does not provide heating; and the control unit places the exhaust gas control apparatus in the first control mode or the third control mode in the first operation region, and places the exhaust gas control apparatus in the second control mode or the third control mode in the second operation region.