Abstract: An exhaust gas purifying method for an internal combustion engine, including determining an amount of particulates in an exhaust gas which is accumulated in a particulate filter disposed within an exhaust passage of the engine, determining whether the particulate filter is at an adequate state for regeneration, and executing regeneration of the particulate filter by controlling oxygen concentration in the exhaust gas depending on the amount of the trapped particulates when it is determined that the particulate filter is at the adequate state and the amount of the accumulated particulates exceeds a first preset value. An exhaust gas purifying apparatus corresponding to the method.

Abstract: A combustion control apparatus operates an internal combustion engine in a split retard combustion mode during regenerating an exhaust purifier such as a particulate filter. In the split retard combustion mode, the combustion control apparatus controls a first fuel injection to cause preliminary combustion at or near top dead center, and controls a second fuel injection to cause main combustion after an end of the preliminary combustion. In this manner, the combustion control apparatus controls an exhaust gas temperature, or an exhaust air-fuel ratio, without increasing exhaust smoke. During the split retard combustion mode, the combustion control apparatus controls an EGR rate of the engine. The EGR rate in the split retard combustion mode is set lower than in the normal combustion mode, in each operating point of the engine.

Abstract: A combustion control apparatus operates an internal combustion engine in a split retard combustion mode during regenerating an exhaust purifier such as a NOx trap. In the split retard combustion mode, the combustion control apparatus controls a first fuel injection to cause preliminary combustion at or near top dead center, and controls a second fuel injection to cause main combustion after an end of the preliminary combustion. In this manner, the combustion control apparatus controls an exhaust gas temperature, or an exhaust air-fuel ratio, without increasing exhaust smoke. During the split retard combustion mode, the combustion control apparatus controls a quantity of the first fuel injection, in accordance with an ignition lag of the preliminary combustion.

Abstract: A combustion control apparatus operates an internal combustion engine in a split retard combustion mode during regenerating an exhaust purifier such as a NOx trap. In the split retard combustion mode, the combustion control apparatus controls a first fuel injection to cause preliminary combustion at or near top dead center, and controls a second fuel injection to cause main combustion after an end of the preliminary combustion. In this manner, the combustion control apparatus controls an exhaust gas temperature, or an exhaust air-fuel ratio, without increasing exhaust smoke. During the split retard combustion mode, the combustion control apparatus controls the excess air ratio to vary the exhaust gas temperature, if there is a request for shifting the exhaust gas temperature. The combustion control apparatus adjusts the second fuel injection timing in accordance with the excess air ratio.

Abstract: A combustion control apparatus for an internal combustion engine, including an exhaust gas purifier, and a control unit programmed to selectively implement a first combustion mode and a second combustion mode, the second combustion mode providing main combustion and preliminary combustion at or near compression top dead center prior to the main combustion, and starting the main combustion after the preliminary combustion is completed. The control unit is programmed to switch from the first combustion mode to the second combustion mode when a request to switch from the first combustion mode to the second combustion mode is made based on a condition of the exhaust gas purifier, and the engine continues to operate for a predetermined time or longer under condition enabling the second combustion mode.

Abstract: In an internal combustion engine equipped with a fuel injection system and an exhaust purifying device, such as NOx trap catalyst and/or diesel particulate filter (DPF), a control unit is provided. The control unit controls the fuel injection system to permit the engine to have a predetermined combustion mode in which, under a predetermined condition of the exhaust purifying device, the fuel injection system causes the engine to carry out a main combustion to produce a torque and at least one preliminary combustion prior to the main combustion. The at least one preliminary combustion is effected at a timing in the vicinity of top dead center of compression stroke, and the main combustion is effected at a first timing after completion of the preliminary combustion.

Abstract: The regeneration control system is provided that conducts a regeneration processing for oxidizing particulate matter collected in the diesel particulate filter (DPF) whereby the regeneration processing can be performed efficiently while avoiding the melting of the diesel particulate filter. The regeneration control system is provided for an exhaust filter wherein at least one parameter selected from among the target filter temperature, target exhaust air-fuel ratio, and target regeneration control time in the DPF regeneration is varied in accordance with the amount of particulate matter when the exhaust air-fuel ratio and exhaust temperature are controlled to perform the DPF regeneration by staged retarded combustion, which is composed of preliminary combustion that is performed at least once in the vicinity of the top dead center, and main combustion that causes the generation of main torque and is initiated after the preliminary combustion has been completed.

Abstract: In combustion control apparatus and method for an internal combustion engine, an exhaust gas purifying section is disposed in an exhaust system of the engine, a determination is made, on the basis of a state of the exhaust gas purifying section, whether a request is issued to switch a combustion mode of the engine to a split retard combustion (a predetermined fuel combustion mode) in which a preliminary combustion is carried out at least once at or near to a top dead center and a main combustion to develop a main torque is started after a completion of the preliminary combustion, and the combustion mode of the engine is switched to the split retard combustion when the combustion mode switching request determining section determines that the request is issued and during a low load driving state of the engine.

Abstract: An exhaust gas cleaning system is provided that comprises a particulate filter and an NOx trapping catalytic converter disposed upstream of the particulate filter. The exhaust gas cleaning system is configured to determine a combustion amount of the particulate matter accumulated in the particulate filter that are combusted by the NOx in the exhaust gas, and adjust the combustion amount of the particulate matter based on an NOx adsorption condition of the NOx trapping catalytic converter. Then, the exhaust gas cleaning system is configured to estimate a particulate matter accumulation amount in the particulate filter by subtracting the adjusted combustion amount of the particulate matter from a discharge amount of the particulate matter. Thus, the amount of particulate matter accumulated in the particulate filter is estimated more accurately by taking into consideration the combustion of particulate matter by NOx in the exhaust gas.

Abstract: In a combustion control system, a control unit determines, based on an operating condition of an exhaust purifying device, whether a request for an exhaust temperature rise or a rich A/F ratio engine operating mode is present. The control unit executes, by way of fuel injection control in presence of the request of the exhaust temperature rise or the rich operating mode, a split retard combustion mode in which a main combustion needed to produce a main engine torque and at least one preliminary combustion occurring prior to the main combustion are both achieved, and the preliminary combustion occurs near top dead center on a compression stroke, and the main combustion initiates after completion of the preliminary combustion. The control unit simultaneously executes an exhaust-emission reduction control that reduces HC and CO emissions, while keeping the excess air factor at a desired value in the catalyst deactivated state.

Abstract: In combustion control apparatus and method for an internal combustion engine, an exhaust gas purifying section is disposed in an exhaust system of the engine, a determination is made, on the basis of a state of the exhaust gas purifying section, whether a request is issued to switch a combustion mode of the engine to a split retard combustion (predetermined fuel combustion mode) in which a preliminary fuel combustion is carried out at least once at or near to a top dead center and a main fuel combustion to develop a main torque is started after a completion of the preliminary fuel combustion, and the combustion mode of the engine is switched to the split retard combustion when the combustion mode switching request determining section determines that the request is issued and during a transient driving state of the engine.

Abstract: In exhaust gas purifying apparatus and method for an internal combustion engine, a degree of a performance deterioration of am NOx trap catalyst is determined on the basis of a detected air-fuel ratio variation time difference, at the performance deterioration determination of the NOx trap catalyst, the degree of the performance deterioration with at least one of correcting factors of a quantity of NOx trapped by means of the NOx trap catalyst, a reducing agent supply quantity by which a reducing agent is supplied to the NOx trap catalyst, and catalyst temperature which is a temperature of the NOx trap catalyst, and at least one of the correcting factors is reflected on the determination of the degree of the performance deterioration of the NOx trap catalyst.

Abstract: An exhaust purifying device is arranged in an exhaust gas passage extending from an internal combustion engine. The exhaust purifying device includes a NOx trapping catalyst that traps NOx in the exhaust gas when an exhaust air/fuel ratio is leaner than stoichiometric and releases the trapped NOx therefrom when the exhaust air/fuel ratio is richer than stoichiometric, and a particulate filter that collects a particulate matter in the exhaust gas. A condition detecting device is arranged to detect a condition of the particulate filter. An exhaust air/fuel ratio control device is arranged to control the exhaust gas from the engine in such a manner that the exhaust gas has a target exhaust air/fuel ratio. When the exhaust air/fuel ratio is changed from a stoichiometric or richer side to a leaner side, the exhaust air/fuel ratio control device varies the exhaust air/fuel ratio under the leaner air/fuel exhaust condition in accordance with the condition of the particulate filter.

Abstract: An exhaust gas purification system for an internal combustion engine (1) is provided which comprises a Nox trap catalyst (13) and an air/fuel ratio controller (20) for controlling the exhaust gas purification system so that an exhaust air/fuel ratio is made rich in a premix combustion mode when it is the time for purifying trapped NOx of the NOx trap catalyst and the NOx trap catalyst is activated (S13) and that the exhaust air/fuel ratio is made rich in a diffusion combustion mode when it is the time for purifying trapped NOx of the Nox trap catalyst and the Nox trap catalyst is not activated (S15). An exhaust gas purification method is also provided.

Abstract: In order to improve performance of NOx reduction, an additional fuel injection immediately after a main fuel injection is performed. By such additional fuel injection, hydrogen (H2) is supplied to a NOx trap catalyst. And in order to prevent engine output torque from varying by the additional fuel injection, the main fuel injection is controlled by whether the additional fuel injection is performed.

Abstract: In exhaust gas purifying apparatus and method for an internal combustion engine, an abnormality determination of an NOx (Nitrogen Oxides) removing catalyst is executed on the basis of output values of both of a first exhaust gas atmosphere detecting section and a second exhaust gas atmosphere detecting section (for example, oxygen concentration sensors interposed in an exhaust passage of the engine between inlet and outlet portions of the NOx removing catalyst) from a time at which an output value of the first exhaust gas atmosphere detecting section is varied to a first predetermined value to a time at which the output value of the second exhaust gas atmosphere detecting section is reached to a second predetermined value when an exhaust gas atmosphere varying section (control unit) increases the ratio of a reducing agent in the exhaust gas.

Abstract: An exhaust gas purifying system for an internal combustion engine of an automotive vehicle. The exhaust gas purifying system includes an exhaust gas purifying catalyst disposed in an exhaust gas passage of the engine to remove an exhaust gas component. A concentration sensor is disposed in the exhaust gas passage downstream of the exhaust gas purifying catalyst to detect a concentration of the exhaust gas component. Additionally, a control unit is provided programmed to carry out (a) detecting an activity transition time at which the exhaust gas purifying catalyst changes from an inactive state to an active state, in accordance with the concentration of the exhaust gas component detected by the concentration sensor, and (b) judging a deterioration of the exhaust gas purifying catalyst at the activity transition time.

Abstract: An exhaust gas purification apparatus for an internal combustion engine comprises a NOx trap catalyst disposed in an exhaust passage of the internal combustion engine and a control unit. At a purification timing, the control unit determines a space velocity of exhaust gas and selectively switches between a first air-fuel ratio control mode for controlling the air-fuel ratio of the exhaust gas to a rich air-fuel ratio with no need to decrease a concentration of oxygen in the exhaust gas when the determined space velocity is lower than or equal to a threshold value, and selects a second air-fuel ratio control mode for not only controlling the air-fuel ratio of the exhaust gas to a rich air-fuel ratio but also making the concentration of oxygen in the exhaust gas lower than that of the first air-fuel ratio control mode when the determined space velocity is higher than the threshold value.

Abstract: An exhaust gas purification system for an internal combustion engine (1) is provided which comprises a Nox trap catalyst (13) and an air/fuel ratio controller (20) for controlling the exhaust gas purification system so that an exhaust air/fuel ratio is made rich in a premix combustion mode when it is the time for purifying trapped NOx of the NOx trap catalyst and the NOx trap catalyst is activated (S13) and that the exhaust air/fuel ratio is made rich in a diffusion combustion mode when it is the time for purifying trapped NOx of the Nox trap catalyst and the Nox trap catalyst is not activated (S15). An exhaust gas purification method is also provided.

Abstract: A diesel particulate filter 14 that traps particulate matters in an exhaust gas and a NOx trap catalyst 13 that traps NOx in the exhaust gas are disposed in an exhaust passage (10) in an internal combustion engine (1). When a regeneration timing of the diesel particulate filter (14) and one of a regeneration timing of SOx and a regeneration timing of NOx are overlapped, the diesel particulate filter regeneration is carried out first and thereafter, the SOx regeneration or the NOx regeneration is carried out.