An exhaust emission control device for an engine is provided with a first purifying catalyst including an HC adsorbent that adsorbs HC at a low temperature and releases HC at a high temperature and a diesel oxidation catalyst capable of oxidizing HC, a second purifying catalyst including a NOx catalyst capable of storing NOx contained in exhaust, a NOx catalyst regenerator that regenerates the NOx catalyst while raising the temperature of the NOx catalyst, and HC controller that decides whether the amount of adsorbed HC that is HC adsorbed by the HC adsorbent is equal to or more than a preset reference amount and, when the amount of adsorbed HC is decided to be equal to or more than the reference amount, raises the temperature of the first purifying catalyst.

In a hybrid vehicle, suppression of an amount of fuel consumed for reducing NOx stored in an NSR catalyst and suppression of deterioration in exhaust gas components due to unreacted fuel flowing out from the NSR catalyst are made compatible with each other. Predetermined power source control is carried out in accompany with the execution of NOx reduction processing to supply fuel to the NSR catalyst. In the predetermined power source control, an engine rotation speed of an internal combustion engine is made to decrease or an operation of the internal combustion engine is made to stop, and an electric motor is controlled so as to compensate for required torque. Further, during a period of execution of the predetermined power source control, a lower limit value of a predetermined target SOC range for an SOC of a battery is changed to a value smaller than at times other than the period of execution of the predetermined power source control.

Systems, methods, and apparatuses for adaptive regeneration of aftertreatment system components. The system may include an aftertreatment system and a controller. The controller is configured to access one or more parameters indicative of an ambient condition, determine a regeneration type of a regeneration process for a component of the aftertreatment system, determine an application in condition, and modify a parameter for the regeneration process for the component of the aftertreatment system. In some instances, the controller initiates the regeneration process. In some instances, the one or more parameters include an ambient air temperature, a reductant tank temperature, or a particulate matter sensor temperature. In some instances, the modified parameter includes a target regeneration temperature, a regeneration duration, a dwell time between regeneration process, a threshold value for the regeneration process, or a minimum regeneration temperature.

An exhaust gas purification apparatus for an internal combustion engine includes: a controller comprising at least one processor is configured to carry out rich spike; wherein the controller carries out supply control to supply a reducing agent to a post-stage catalyst, wherein in cases where a temperature of an NSR catalyst becomes less than a predetermined determination temperature in at least a part of a determination period of time, the controller carries out the supply control according to the execution of current rich spike; wherein the controller controls such that in cases where the storage amount of NOx is the same, an amount of supply of the reducing agent in the supply control is made larger as a period of time in which the temperature of the NSR catalyst becomes less than the predetermined determination temperature in the determination period of time becomes longer.

Rich spike is carried out in an efficient manner. In an exhaust gas purification apparatus for an internal combustion engine which performs lean burn operation, the apparatus includes an NOx storage reduction catalyst, a controller to carry out rich spike, to calculate a storage amount of NOx, to calculate a storage amount of nitrates, and calculate a nitrate ratio, wherein the controller controls a timing at which the rich spike is carried out, based on the nitrate ratio.

A rich control for temporarily declining an air-fuel ratio of exhaust gas discharged from an engine combustion chamber is performed by an additional fuel being injected into a cylinder in an expansion stroke or an exhaust stroke in a state where a throttle opening degree is switched from a base throttle opening degree to a throttle opening degree for the rich control and an EGR rate is switched from a base EGR rate to an EGR rate for the rich control. The rich control is terminated by returning the throttle opening degree (VTH) to the base throttle opening degree (VTHB), stopping the injection of the additional fuel (Qa), and temporarily increasing the amount of a main fuel (Qm). Then, an EGR control valve opening degree (VEGR) is controlled such that the EGR rate (REGR) is returned to the base EGR rate (REGRB).

A control apparatus for an internal combustion engine having an exhaust gas purification device which is arranged in an exhaust passage and includes a NOx storage reduction (NSR) catalyst. The control apparatus, when the air fuel ratio of the air-fuel mixture is shifted from a lean air fuel ratio to the stoichiometric air fuel ratio, determines a predetermined NO.sub.x amount so as to be larger when the temperature detected by the first detection unit is high in comparison with when the detected temperature is low, and when the storage amount of NO.sub.x in the NSR catalyst is larger than the predetermined NO.sub.x amount, performs the rich spike processing and then controls the air fuel ratio to the stoichiometric air fuel ratio, whereas when otherwise, controls the air fuel ratio to the stoichiometric air fuel ratio without performing the rich spike processing.

An exhaust emission control system of an engine is provided, which includes a NO.sub.x catalyst disposed in an exhaust passage for storing NO.sub.x within exhaust gas when an air-fuel ratio of the exhaust gas is lean, and reducing the stored NO.sub.x when the air-fuel ratio is approximately stoichiometric or rich. A processor executes a NO.sub.x reduction controlling module for performing, when the NO.sub.x stored amount exceeds a given amount, a NO.sub.x reduction control in which a fuel injector performs a post injection of fuel to continuously control the air-fuel ratio to a target ratio so that the stored NO.sub.x is reduced to be below a given amount, the target air-fuel ratio being a ratio at which the stored NO.sub.x is reducible, the post injection causing the injected fuel to combust inside a cylinder, the execution of the control permitted when an engine load is within a medium load range.

Provided is an exhaust purification system including: an NOx occlusion reduction type catalyst (32), a catalyst temperature estimating unit (115), an NOx occlusion amount estimating unit (113), a regeneration control unit (100) that performs catalyst regeneration of bringing an exhaust gas into a rich state to recover NOx occlusion capacity of the NOx occlusion reduction type catalyst (32), an interval setting unit (118) that sets a target interval from the termination of the catalyst regeneration to a start of next catalyst regeneration, a catalyst regeneration start processing unit (110) that starts the next catalyst regeneration when the NOx occlusion amount is equal to or greater than a threshold and an elapsed time from the termination of the catalyst regeneration reaches the target interval, and an interval target value correcting unit (119) that extends and corrects the target interval based on the NOx occlusion amount when the catalyst temperature is lower than a predetermined catalyst activation temperature.

A method includes initiating a low engine-out NOx (LEON) mode by controlling a component of a vehicle having an aftertreatment system to decrease an instantaneous engine-out NOx (EONOx) amount. The method also includes comparing a temperature of the aftertreatment system to a threshold temperature. The method also includes responsive to determining that the temperature of the aftertreatment system exceeds the threshold temperature, disengaging the LEON mode. The method also includes responsive to determining that the temperature of the aftertreatment system is below the threshold temperature, comparing a NOx value to a NOx value threshold. The method also includes disengaging the LEON mode responsive to determining that the NOx value exceeds the NOx value threshold.