A control system for an engine is provided, which includes an engine body formed with a cylinder, a NO.sub.x catalyst, an oxidation catalyst, a PM filter, a fuel injector configured to perform a main injection and a post injection, and a controller configured to execute a DeNO.sub.x control in which the fuel injector is controlled to perform the main and post injections so that an air-fuel ratio of exhaust gas is brought close to the stoichiometric air-fuel ratio or becomes rich and fuel supplied into the cylinder by the post injection combusts therein, and a filter regenerating control in which the fuel injector is controlled to perform the main and post injections so that the air-fuel ratio becomes lean and the fuel supplied into the cylinder by the post injection causes no combustion therein, the controller executing the DeNO.sub.x control and the filter regenerating control consecutively in this order.

A method and a unit for operating or for the operation of a fuel metering system of an internal combustion engine, in particular in a motor vehicle, and it being provided, in particular, that at least one operating variable of the internal combustion engine is detected, a dynamic operating state of the internal combustion engine is detected based on the at least one detected operating variable, and a dynamic correction to the fuel metering system of the internal combustion engine is carried out for a detected dynamic operating state of the internal combustion engine, taking into account the efficiency of an NOx exhaust gas aftertreatment system.

An exhaust gas control apparatus includes a fuel injection device, a NOx occlusion reduction catalyst, a fuel addition valve, an inflow gas adjustment device, and an electronic control unit. The electronic control unit executes a low flow rate reduction treatment for removing NO.sub.x occluded in the NOx occlusion reduction catalyst after fuel supply from the fuel injection device is stopped. The electronic control unit controls the inflow gas adjustment device such that a ratio of oxygen to the fuel added to the NOx occlusion reduction catalyst at a time when a temperature of the NOx occlusion reduction catalyst is below an activation temperature becomes higher than a ratio of oxygen to the fuel added to the NOx occlusion reduction catalyst at a time when the temperature of the NOx occlusion reduction catalyst is equal to or higher than the activation temperature during the low flow rate reduction treatment.

A method is disclosed for operating an automotive system having an internal combustion engine equipped with an exhaust gas aftertreatment system including a Lean NO.sub.x Trap (LNT) upstream of a Selective Catalytic Reduction washcoated particulate filter (SCRF). A LNT inlet temperature is monitored. A parameter representative of a quantity of NO.sub.X stored in the LNT is also monitored. A map correlating the LNT inlet temperature and the quantity of NO.sub.X stored in the LNT is used to estimate an ammonia quantity produced during a LNT regeneration. A LNT regeneration is performed, if the estimated ammonia quantity is greater than a threshold value thereof.

An exhaust gas control system for a hybrid vehicle may include a NOx storage-reduction catalyst, and an electronic control unit. The electronic control unit may control the internal combustion engine so as to reduce an engine speed or stop operation of the internal combustion engine and control an electric motor so as to compensate for needed torque of the hybrid vehicle when NOx reduction treatment is executed in a case where a charging amount of a battery when a predetermined NOx reduction execution condition is satisfied is equal to or larger than a predetermined charging amount, and control the internal combustion engine so as to maintain operational state of the internal combustion engine at a normal operation when the NOx reduction treatment is executed in a case where the charging amount of the battery when the predetermined NOx reduction execution condition is satisfied is smaller than the predetermined charging amount.

There is provided a technology pertaining to abnormality diagnosis of an NSR catalyst that enables the diagnosis that the NSR catalyst is abnormal to be made even when the degree of deterioration of the NSR catalyst is relatively small yet. An abnormality diagnosis apparatus is applied to an exhaust gas purification apparatus having an NSR catalyst and a fuel addition valve. The abnormality diagnosis apparatus includes a controller configured to perform a specific fuel addition process and diagnose the NSR catalyst. The controller starts the specific fuel addition process when the NSR catalyst is in a specific start condition, and diagnoses the NSR catalyst on the basis of the quantity of NOx flowing out of the NSR catalyst over a specific period in the period from when the specific fuel addition process is started to when the temperature of the NSR catalyst reaches the thermal desorption temperature.

A control system includes a sensor configured to detect information associated with an area surrounding a vehicle and an electronic control unit configured to control an automated driving of the vehicle. The electronic control unit includes a driving plan generation unit, a driving control unit, a regeneration control unit configured to control a process for regenerating an engine exhaust gas treatment apparatus, and a lane selection unit configured to predict an engine load associated with traveling in each lane of a plurality of lanes. The lane selection unit is also configured to select a lane which would cause an increase in engine load when the control for regenerating the exhaust gas treatment apparatus is being performed by the regeneration control unit. The control system is configured to cause the vehicle to be driven in the lane selected by the lane selection unit.

A fuel control module controls fuel injection of an engine based on a predetermined lean air/fuel ratio. The predetermined lean air/fuel ratio is fuel lean relative to a stoichiometric air/fuel ratio for the fuel. A cylinder control module selectively deactivates opening of intake and exhaust valves of M cylinders of the engine to increase removal of nitrogen oxide (NOx) from exhaust. M is an integer greater than 0 and less than a total number of cylinders of the engine. The fuel control module further: disables fueling of the M cylinders while opening of the intake and exhaust valves of the M cylinders is deactivated; and, while fueling of the M cylinders is disabled and opening of the intake and exhaust valves of the M cylinders is deactivated, controls fuel injection of other cylinders based on a predetermined rich air/fuel ratio that is fuel rich relative to the stoichiometric air/fuel ratio.

An exhaust purification system is provided with a NOx-occlusion-reduction-type catalyst 32 that occludes NOx in exhaust when the exhaust is in a lean state and reduces and purifies the occluded NOx when the exhaust is in a rich state, and a NOx purge rich control unit 140 for reducing and purifying NOx occluded in the NOx-occlusion-reduction-type catalyst 32 by putting the exhaust into the rich state by repetitively performing fuel injection control of at least one of post injection and exhaust pipe injection at a predetermined interval.

A method and apparatus are disclosed for controlling the operation of an aftertreatment system for a motor vehicle having a Lean NO.sub.x Trap and a tail pipe for conveying exhaust gasses from the LNT to the external environment. Values are calculated for a NO.sub.x content in the exhaust gasses flowing in the tail pipe and the quantity of NO.sub.x stored in the LNT. A DeNO.sub.x request index is calculated as a function of these values. A raw threshold value of the DeNO.sub.x request index is calculated as a function of a LNT temperature and of an exhaust gas mass flow. A corrected threshold value of the DeNO.sub.x request index is calculated as a function of the raw threshold value of the DeNO.sub.x request index and of a correction factor. A DeNO.sub.x regeneration is initiated when the calculated value of the DeNO.sub.x request index is larger than the corrected threshold value.