Exhaust gas cleaning device for internal combustion engine

An exhaust gas cleaning device for an internal combustion engine, the exhaust gas cleaning device comprising:

• a particulate filter that includes a filter substrate, which holds catalyst thereon for combusting and removing particulate matter through use of reaction heat of oxidation reaction of the catalyst to regenerate the particulate filter upon capturing of the particulate matter of exhaust gas exhausted from the internal combustion engine;
• a catalyst activation level sensing means for sensing an activation level of the catalyst;
• and
• an injection pattern selecting means for selecting one of first to third injection patterns, wherein:
• the first injection pattern is for performing a single fuel injection per heat cycle of the internal combustion engine and is for mainly generating an output power of the internal combustion engine;
• the second injection pattern is for performing multiple fuel injections in multiple injection stages, respectively, per heat cycle of the internal combustion engine;
• a first one of the multiple fuel injections of the second injection pattern is substantially the same as the fuel injection of the first injection pattern;
• the multiple fuel injections of the second injection pattern further include at least one subsequent fuel injection, which is performed on a retarded side of the first one of the multiple fuel injections of the second injection pattern and has a higher ratio of waste heat in comparison to that of the first one of the multiple fuel injections, so that a temperature of the exhaust gas outputted from the internal combustion engine is increased, and a desired output power of the internal combustion engine is generated with the second injection pattern;
• the third injection pattern is for performing multiple fuel injections in multiple injection stages, respectively, per heat cycle of the internal combustion engine;
• a first one of the multiple fuel injections of the third injection pattern is substantially the same as the fuel injection of the first injection pattern;
• the multiple fuel injections of the third injection pattern further include at least one subsequent fuel injection, which is performed on a retarded side of the first one of the multiple fuel injections of the third injection pattern;
• an injection interval between an end point of the first one of the multiple fuel injections of the third injection pattern and a start point of a subsequent one of the at least one subsequent fuel injection of the third injection pattern is greater than that of the second injection pattern, so that a ratio of uncombusted fuel component of the exhaust gas generated upon combustion of fuel of the subsequent one of the at least one subsequent fuel injection in the third injection pattern becomes higher than that of the second injection pattern, and the thus generated uncombusted fuel component is supplied to the particulate filter, and the desired output power of the internal combustion engine is generated with the third injection pattern;
• the injection pattern selecting means selects one of the second and third injection patterns upon receiving a request for regenerating the particulate filter;
• the injection pattern selecting means selects the second injection pattern when the activation level of the catalyst, which is sensed by the catalyst activation level sensing means, is relatively low and thereby is equal to or less than a threshold value;
• the at least one subsequent fuel injection of the second injection pattern includes multiple subsequent fuel injections;
• and
• injection intervals of the multiple subsequent fuel injections of the second injection pattern are increased one after another toward a last one of the multiple subsequent fuel injections of the second injection pattern.

An exhaust gas cleaning device for an internal combustion engine, the exhaust gas cleaning device comprising:

• a particulate filter that includes a filter substrate, which holds catalyst thereon for combusting and removing particulate matter through use of reaction heat of oxidation reaction of the catalyst to regenerate the particulate filter upon capturing of the particulate matter of exhaust gas exhausted from the internal combustion engine;
• a catalyst activation level sensing means for sensing an activation level of the catalyst;
• an injection pattern selecting means for selecting one of first to third injection patterns;
• and
• an injection stage number setting means for setting a number of multiple injection stages in the second injection pattern based on a temperature of the exhaust gas, wherein:
• the first injection pattern is for performing a single fuel injection per heat cycle of the internal combustion engine and is for mainly generating an output power of the internal combustion engine;
• the second injection pattern is for performing multiple fuel injections in the multiple injection stages, respectively, per heat cycle of the internal combustion engine;
• a first one of the multiple fuel injections of the second injection pattern is substantially the same as the fuel injection of the first injection pattern;
• the multiple fuel injections of the second injection pattern further include at least one subsequent fuel injection, which is performed on a retarded side of the first one of the multiple fuel injections of the second injection pattern and has a higher ratio of waste heat in comparison to that of the first one of the multiple fuel injections, so that the temperature of the exhaust gas outputted from the internal combustion engine is increased, and a desired output power of the internal combustion engine is generated with the second injection pattern;
• the third injection pattern is for performing multiple fuel injections in multiple injection stages, respectively, per heat cycle of the internal combustion engine;
• a first one of the multiple fuel injections of the third injection pattern is substantially the same as the fuel injection of the first injection pattern;
• the multiple fuel injections of the third injection pattern further include at least one subsequent fuel injection, which is performed on a retarded side of the first one of the multiple fuel injections of the third injection pattern;
• an injection interval between an end point of the first one of the multiple fuel injections of the third injection pattern and a start point of a subsequent one of the at least one subsequent fuel injection of the third injection pattern is greater than that of the second injection pattern, so that a ratio of uncombusted fuel component of the exhaust gas generated upon combustion of fuel of the subsequent one of the at least one subsequent fuel injection in the third injection pattern becomes higher than that of the second injection pattern, and the thus generated uncombusted fuel component is supplied to the particulate filter, and the desired output power of the internal combustion engine is generated with the third injection pattern;
• the injection pattern selecting means selects one of the second and third injection patterns upon receiving a request for regenerating the particulate filter;
• and
• the injection pattern selecting means selects the second injection pattern when the activation level of the catalyst, which is sensed by the catalyst activation level sensing means, is relatively low and thereby is equal to or less than a threshold value.