Exhaust temperature raising apparatus and method for internal combustion engine

An exhaust temperature raising apparatus has an exhaust throttle valve (15) that adjusts the engine exhaust amount based on the amount of throttling, and an injector (12) that performs main injection and a sub-injection directly into a cylinder, a combination of an ECU (4), the injector (12), and the exhaust throttle valve (15) as exhaust gas temperature increase means for, during an engine warm-up, performing and controlling the exhaust throttling by the exhaust throttle valve and performing and controlling an exhaust gas temperature increase through combustion attributed to the main injection performed in an excess-air condition and combustion attributed to the sub-injection, an exhaust gas temperature sensor (16) that monitors a state of temperature increase of the exhaust gas caused by performance of the exhaust gas temperature increase means, and the ECU (4) as monitor means abnormality determination means for determining whether the exhaust gas temperature sensor (16) has an abnormality, and the ECU (4) as exhaust gas temperature increase stop means for stopping the operation of the exhaust gas temperature increase means when the ECU (4) determines that the exhaust gas temperature sensor (16) has an abnormality.