Abstract: An exhaust gas cleaning apparatus includes a combustion mode shifter that shifts combustion in a cylinder of an engine from a lean-burn mode to a rich-burn mode for enabling a LNT to reduce NOx contained in the exhaust gas. The combustion mode shifter is configured to: estimate a torque-producing fuel quantity for a fuel injection made by a fuel injector when the combustion is in the lean-burn mode; estimate an excess oxygen ratio for an upcoming fuel injection during the shifting of the combustion from the lean-burn mode to the rich-burn mode; estimate a fuel burning percentage for the upcoming fuel injection based on the excess oxygen ratio; set a command injection quantity for the upcoming fuel injection based on the torque-producing fuel quantity and the fuel burning percentage; and control the fuel injector to inject the command injection quantity of fuel into the cylinder in the upcoming fuel injection.

Abstract: An exhaust gas cleaning apparatus includes a LNT, a fuel adding device, an exhaust gas returning passage, and a controller. The LNT is provided in an exhaust gas passage of an engine. The fuel adding device is located upstream of the LNT to add fuel to exhaust gas flowing through the exhaust pipe. The exhaust gas returning passage branches off from the exhaust gas passage at a position downstream of the fuel adding device. The controller controls the apparatus to selectively operate in one of first and second modes according to the operating condition of the engine. In the first mode, the fuel adding device adds the fuel to the exhaust gas with the exhaust gas returning passage closed; in the second mode, the exhaust gas is partially returned to an intake air passage through the exhaust gas returning passage without the fuel being added by the fuel adding device.

Abstract: An exhaust purification device has a NOx catalyst that occludes NOx contained in exhaust gas at a lean air fuel ratio and that purifies (reduces) and discharges the occluded NOx at a rich air fuel ratio. The device performs full purge for discharging substantially an entirety of the occluded NOx at once based on establishment of an execution condition of the full purge to recover exhaust purification performance of the NOx catalyst. The device has a program for performing partial purge for discharging only part of the occluded NOx before the execution of the full purge. The device consecutively and repeatedly performs the partial purge except for the period in which the full purge is performed.

Abstract: An exhaust purification catalyst diagnosis device for diagnosing a degree of performance degradation of a NOx catalyst, which is provided in an exhaust system of an engine for exhaust purification, has a program that determines whether temperature of the NOx catalyst is within a predetermined diagnosis permission range before catalyst diagnosis processing and a program that controls the temperature of the NOx catalyst into the diagnosis permission range before the catalyst diagnosis processing if it is determined that the temperature of the NOx catalyst is outside the diagnosis permission range. Thus, the exhaust purification catalyst diagnosis device can perform the catalyst diagnosis processing frequently with high reliability and high accuracy, while maintaining suitable emission.

Abstract: An ECU controls a rich purge in the internal combustion engine by temporarily changing an air/fuel ratio of the exhaust gas into a rich range to deoxidize and remove absorbed NOx, which is absorbed by an NOx storage and reduction catalyst of an NOx catalytic converter. The ECU changes a degree of richness of the air/fuel ratio at a time of performing the rich purge based on a state of the NOx catalytic converter.

Abstract: An NOx catalytic converter, which includes an NOx storage and reduction catalyst, absorbs NOx contained in exhaust gas of an engine. The absorbed NOx is deoxidized and eliminated when an NOx deoxidizing agent is supplied to the catalytic converter. An ECU determines a purifying performance of the catalytic converter based on one of an amount of supplied NOx deoxidizing agent, which is required to deoxidize and remove absorbed NOx at the NOx catalytic converter, and a parameter that correlates with the amount of the supplied NOx deoxidizing agent. The ECU prohibits the determining of the purifying performance of the catalytic converter when it is determined that supplied unburnt fuel, which is supplied to the catalytic converter, is in an excessive state.

Abstract: When it is determined that fuel in use is low-cetane fuel or a present location point is at a high altitude, a map of rich combustion, exhaust gas fuel addition or a post-injection is rewritten on the occasion of reduction of NOx to inhibit a misfire. Also, deterioration of fuel consumption due to regeneration of a diesel particulate filter is inhibited by suppressing excessive discharge of smoke due to the rich combustion. Thus, an exhaust purification device of an internal combustion engine capable of achieving both of inhibition of the deterioration in the fuel consumption due to the regeneration of the diesel particulate filter and inhibition of torque shock accompanying the misfire during the rich combustion for the NOx reduction is provided.

Abstract: A control device of an internal combustion engine calculates ignition delays in lean combustion and rich combustion, standardizes the ignition delays based on ignition timing, and further standardizes the ignition delays based on injection quantity and injection timing of pilot injection respectively. The control device calculates a present ignition delay by linear interpolation of the standardized ignition delays in the lean combustion and the rich combustion. Moreover, the control device corrects the present ignition delay with the ignition timing and further corrects the present ignition delay with the injection quantity and the injection timing of the pilot injection. The control device calculates a command value of the injection timing by subtracting the corrected present ignition delay from target ignition timing.

Abstract: An exhaust purification device is provided to selectively perform a combustion purge control and an exhaust addition purge control in response to an operation state of the internal combustion engine. The combustion purge control process is performed in the case where a NOx occlusion amount of a NOx catalyst is larger than or equal to a first threshold value, and the exhaust addition purge control process is performed in the case where the NOx occlusion amount of the NOx catalyst is larger than or equal to a second threshold value which is larger than the first threshold value.

Abstract: A control device of an internal combustion engine calculates ignition delays in lean combustion and rich combustion, standardizes the ignition delays based on ignition timing, and further standardizes the ignition delays based on injection quantity and injection timing of pilot injection respectively. The control device calculates a present ignition delay by linear interpolation of the standardized ignition delays in the lean combustion and the rich combustion. Moreover, the control device corrects the present ignition delay with the ignition timing and further corrects the present ignition delay with the injection quantity and the injection timing of the pilot injection. The control device calculates a command value of the injection timing by subtracting the corrected present ignition delay from target ignition timing.

Abstract: An exhaust gas cleaning apparatus includes a combustion mode shifter that shifts combustion in a cylinder of an engine from a lean-burn mode to a rich-burn mode for enabling a LNT to reduce NOx contained in the exhaust gas. The combustion mode shifter is configured to: estimate a torque-producing fuel quantity for a fuel injection made by a fuel injector when the combustion is in the lean-burn mode; estimate an excess oxygen ratio for an upcoming fuel injection during the shifting of the combustion from the lean-burn mode to the rich-burn mode; estimate a fuel burning percentage for the upcoming fuel injection based on the excess oxygen ratio; set a command injection quantity for the upcoming fuel injection based on the torque-producing fuel quantity and the fuel burning percentage; and control the fuel injector to inject the command injection quantity of fuel into the cylinder in the upcoming fuel injection.

Abstract: An exhaust gas cleaning apparatus includes a LNT, a fuel adding device, an exhaust gas returning passage, and a controller. The LNT is provided in an exhaust gas passage of an engine. The fuel adding device is located upstream of the LNT to add fuel to exhaust gas flowing through the exhaust pipe. The exhaust gas returning passage branches off from the exhaust gas passage at a position downstream of the fuel adding device. The controller controls the apparatus to selectively operate in one of first and second modes according to the operating condition of the engine. In the first mode, the fuel adding device adds the fuel to the exhaust gas with the exhaust gas returning passage closed; in the second mode, the exhaust gas is partially returned to an intake air passage through the exhaust gas returning passage without the fuel being added by the fuel adding device.

Abstract: When it is determined that fuel in use is low-cetane fuel or a present location point is at a high altitude, a map of rich combustion, exhaust gas fuel addition or a post-injection is rewritten on the occasion of reduction of NOx to inhibit a misfire. Also, deterioration of fuel consumption due to regeneration of a diesel particulate filter is inhibited by suppressing excessive discharge of smoke due to the rich combustion. Thus, an exhaust purification device of an internal combustion engine capable of achieving both of inhibition of the deterioration in the fuel consumption due to the regeneration of the diesel particulate filter and inhibition of torque shock accompanying the misfire during the rich combustion for the NOx reduction is provided.

Abstract: An exhaust purification catalyst diagnosis device for diagnosing a degree of performance degradation of a NOx catalyst, which is provided in an exhaust system of an engine for exhaust purification, has a program that determines whether temperature of the NOx catalyst is within a predetermined diagnosis permission range before catalyst diagnosis processing and a program that controls the temperature of the NOx catalyst into the diagnosis permission range before the catalyst diagnosis processing if it is determined that the temperature of the NOx catalyst is outside the diagnosis permission range. Thus, the exhaust purification catalyst diagnosis device can perform the catalyst diagnosis processing frequently with high reliability and high accuracy, while maintaining suitable emission.

Abstract: An exhaust purification device has a NOx catalyst that occludes NOx contained in exhaust gas at a lean air fuel ratio and that purifies (reduces) and discharges the occluded NOx at a rich air fuel ratio. The device performs full purge for discharging substantially an entirety of the occluded NOx at once based on establishment of an execution condition of the full purge to recover exhaust purification performance of the NOx catalyst. The device has a program for performing partial purge for discharging only part of the occluded NOx before the execution of the full purge. The device consecutively and repeatedly performs the partial purge except for the period in which the full purge is performed.

Abstract: An exhaust purification device is provided to selectively perform a combustion purge control and an exhaust addition purge control in response to an operation state of the internal combustion engine. The combustion purge control process is performed in the case where a NOx occlusion amount of a NOx catalyst is lager than or equal to a first threshold value, and the exhaust addition purge control process is performed in the case where the NOx occlusion amount of the NOx catalyst is lager than or equal to a second threshold value which is larger than the first threshold value.

Abstract: An ECU controls a rich purge in the internal combustion engine by temporarily changing an air/fuel ratio of the exhaust gas into a rich range to deoxidize and remove absorbed NOx, which is absorbed by an NOx storage and reduction catalyst of an NOx catalytic converter. The ECU changes a degree of richness of the air/fuel ratio at a time of performing the rich purge based on a state of the NOx catalytic converter.

Abstract: An NOx catalytic converter, which includes an NOx storage and reduction catalyst, absorbs NOx contained in exhaust gas of an engine. The absorbed NOx is deoxidized and eliminated when an NOx deoxidizing agent is supplied to the catalytic converter. An ECU determines a purifying performance of the catalytic converter based on one of an amount of supplied NOx deoxidizing agent, which is required to deoxidize and remove absorbed NOx at the NOx catalytic converter, and a parameter that correlates with the amount of the supplied NOx deoxidizing agent. The ECU prohibits the determining of the purifying performance of the catalytic converter when it is determined that supplied unburnt fuel, which is supplied to the catalytic converter, is in an excessive state.

Abstract: An internal combustion is capable of switching, during engine operation, between a low-temperature combustion state in which an intake air with a high EGR rate is burned to operate the engine, and a normal combustion state in which an intake air with a low EGR rate is burned to operate the engine. In the internal combustion engine, a pilot injection is executed in addition to a main fuel injection, and furthermore the execution of the pilot injection is restricted during the engine operation with a combustion state switched to the low-temperature combustion state.

Abstract: An internal combustion is capable of switching, during engine operation, between a low-temperature combustion state in which an intake air with a high EGR rate is burned to operate the engine, and a normal combustion state in which an intake air with a low EGR rate is burned to operate the engine. In the internal combustion engine, a pilot injection is executed in addition to a main fuel injection, and furthermore the execution of the pilot injection is restricted during the engine operation with a combustion state switched to the low-temperature combustion state.