Exhaust temperature raising apparatus and method for internal combustion engine

An exhaust temperature raising apparatus for an internal combustion engine, comprising:

• an exhaust throttle valve that is provided in an exhaust passage of the internal combustion engine and that adjusts an amount of an exhaust gas flowing in the exhaust passage based on an amount of throttling by the exhaust throttle valve;
• a fuel injection valve that performs a main injection that is a fuel injection for producing an engine output and a sub-injection that is a subsidiary fuel injection after performance of the main injection, directly into a cylinder;
• an exhaust gas temperature increase means for, during an engine operation during which a need to lessen an unburned fuel component contained in an exhaust gas is high, performing and controlling 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 by the fuel injection valve and combustion attributed to the sub-injection;
• an exhaust gas temperature increase monitor means for monitoring a state of temperature increase of the exhaust gas caused by performance of the exhaust gas temperature increase means;
• an exhaust gas temperature increase abnormality determination means for determining whether there is an abnormality regarding the state of temperature increase of the exhaust gas monitored by the exhaust gas temperature increase monitor means;
• and
• an exhaust gas temperature increase stop means for stopping an operation of the exhaust gas temperature increase means when the exhaust gas temperature increase abnormality determination means determines that there is an abnormality regarding the state of temperature increase of the exhaust gas,
• wherein the exhaust gas temperature increase monitor means includes a back pressure sensor provided at a location in the exhaust passage upstream of a location of the exhaust throttle valve, and the exhaust gas temperature increase monitor means monitors the state of temperature increase of the exhaust gas based on a back pressure detected by the back pressure detector.

An exhaust gas temperature raising apparatus for an internal combustion engine, comprising:

• an exhaust throttle valve that is provided in an exhaust passage of the internal combustion engine and that adjusts an amount of an exhaust gas flowing in the exhaust passage based on an amount of throttling of the exhaust throttle valve;
• a fuel injection valve that performs a main injection that is a fuel injection for producing an engine output and a sub-injectin that is a subsidiary fuel injection after performance of the main injection, directly into a cylinder;
• an exhaust gas temperature increase device for, during an engine operation during which a need to lessen an unburned fuel component contained in an exhaust gas is high, performing and controlling 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 by the fuel injection valve and combustion attributed to the sub-injection;
• an exhaust gas temperature increase sensor for sensing a state of temperature increase of the exhaust gas caused by performance of the exhaust gas temperature increase device;
• a sensor abnormality determination device for determining whether the exhaust gas temperature increase sensor has an abnormality;
• and
• an exhaust gas temperature increase stop device for stopping an operation of the exhaust gas temperature increase device when the sensor abnormality determination device determines that the exhaust gas temperature increase sensor has an abnormality;
• wherein the exhaust gas temperature increase sensor includes a back pressure sensor provided at a location in the exhaust passage upstream of a location of the exhaust throttle valve, and the exhaust gas temperature increase sensor monitors the state of temperature increase of the exhaust gas based on a back pressure detected by the back pressure detector.

An exhaust gas temperature raising apparatus for an internal combustion engine, comprising:

• an exhaust throttle valve that is provided in an exhaust passage of the internal combustion engine and that adjusts an amount of an exhaust gas flowing in the exhaust passage based on an amount of throttling of the exhaust throttle valve;
• a fuel injection valve that performs a main injection that is a fuel injection for producing an engine output and a sub-injection that is a subsidiary fuel injection after performance of the main injection, directly into a cylinder;
• an exhaust gas temperature increase device for, during an engine operation during which a need to lessen an unburned fuel component contained in an exhaust gas is high, performing and controlling 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 by the fuel injection valve and combustion attributed to the sub-injection;
• an exhaust gas temperature increase sensor for sensing a state of temperature increase of the exhaust gas caused by performance of the exhaust gas temperature increase device;
• an exhaust gas temperature increase abnormality determination device for determining whether there is an abnormality regarding the state of temperature increase of the exhaust gas sensed by the exhaust gas temperature increase sensor;
• and
• an exhaust gas temperature increase stop device for stopping an operation of the exhaust gas temperature increase device when the exhaust gas temperature increase abnormality determination device determines that there is an abnormality regarding the state of temperature increase of the exhaust gas.