Abstract: An emission control system and method execute a regeneration control such that a catalyst device recovers from poisoning, in a first control mode in which a temperature raising operation and a releasing operation are alternately repeated and in a second control mode in which the temperature raising operation and the releasing operation are alternately repeated. In the first control mode, the temperature raising operation is performed by post injection from a fuel injector. In the second control mode, the temperature raising operation is performed by adding fuel into exhaust gas from an addition valve such that the HC concentration in exhaust gas oscillates with an amplitude within a first specified range and a cycle within a second specified range. The control mode is switched from the first control mode to the second control mode during the regeneration control.

Abstract: A control system includes an ECU that controls supply of fuel from an addition valve and supply of fuel from an injection valve, estimates or detects a degree of end-face clogging on an exhaust-gas inflow side of a NOx catalyst, and sets an inlet temperature of the NOx catalyst by use of the fuel supplied from the injection valve to a higher level and sets an amount of the fuel supplied from the addition valve to a smaller value in a case where the degree of end-face clogging is equal to or larger than a predetermined value, compared to the case where the degree of end-face clogging is smaller than the predetermined value, when there also is a request for regeneration of an exhaust purification filter and/or a request for regeneration of the NOx catalyst.

Abstract: In an internal combustion engine, an exhaust purification catalyst, hydrocarbon feed valve, and particulate filter are arranged in an exhaust passage. Hydrocarbons are injected from the hydrocarbon feed valve by a predetermined period so as to remove NOX which is contained in the exhaust gas in first NOX removal method. While doing this, the particulate matter which is trapped on the particulate filter is removed by raising the temperature of the particulate filter in temperature elevation control. At this time, the hydrocarbon injection for the first NOX removal method is performed by the predetermined period at the preset injection pressure. During the time period when the hydrocarbon injection for the first NOX removal method is not being performed, the hydrocarbon injection for the temperature elevation control is performed by an injection pressure which is set lower than the preset injection pressure.

Abstract: A catalyst regeneration processing apparatus for an internal-combustion engine includes an electronic control unit. The electronic control unit is configured to determine whether a gap is equal to a predetermined degree or less, the gap being a difference between (a) a progress degree of heat deterioration of a NOx catalyst in a predetermined time in a case of assuming that a regeneration process is executed for the predetermined time and (b) a progress degree of heat deterioration of the NOx catalyst in the predetermined time in a case of assuming that the regeneration process is not executed. The electronic control unit is configured to execute the regeneration process in a case of determining that the gap is equal to the predetermined degree or less, even when a sulfur poisoning quantity does not exceed a permissible upper limit quantity.

Abstract: An emission control system and method execute a regeneration control such that a catalyst device recovers from poisoning, in a first control mode in which a temperature raising operation and a releasing operation are alternately repeated and in a second control mode in which the temperature raising operation and the releasing operation are alternately repeated. In the first control mode, the temperature raising operation is performed by post injection from a fuel injector. In the second control mode, the temperature raising operation is performed by adding fuel into exhaust gas from an addition valve such that the HC concentration in exhaust gas oscillates with an amplitude within a first specified range and a cycle within a second specified range. The control mode is switched from the first control mode to the second control mode during the regeneration control.

Abstract: A control system includes an ECU that controls supply of fuel from an addition valve and supply of fuel from an injection valve, estimates or detects a degree of end-face clogging on an exhaust-gas inflow side of a NOx catalyst, and sets an inlet temperature of the NOx catalyst by use of the fuel supplied from the injection valve to a higher level and sets an amount of the fuel supplied from the addition valve to a smaller value in a case where the degree of end-face clogging is equal to or larger than a predetermined value, compared to the case where the degree of end-face clogging is smaller than the predetermined value, when there also is a request for regeneration of an exhaust purification filter and/or a request for regeneration of the NOx catalyst.

Abstract: A catalyst regeneration processing apparatus for an internal-combustion engine includes an electronic control unit. The electronic control unit is configured to determine whether a gap is equal to a predetermined degree or less, the gap being a difference between (a) a progress degree of heat deterioration of a NOx catalyst in a predetermined time in a case of assuming that a regeneration process is executed for the predetermined time and (b) a progress degree of heat deterioration of the NOx catalyst in the predetermined time in a case of assuming that the regeneration process is not executed. The electronic control unit is configured to execute the regeneration process in a case of determining that the gap is equal to the predetermined degree or less, even when a sulfur poisoning quantity does not exceed a permissible upper limit quantity.

Abstract: In an internal combustion engine, an exhaust purification catalyst, hydrocarbon feed valve, and particulate filter are arranged in an exhaust passage. Hydrocarbons are injected from the hydrocarbon feed valve by a predetermined period so as to remove NOX which is contained in the exhaust gas in first NOX removal method. While doing this, the particulate matter which is trapped on the particulate filter is removed by raising the temperature of the particulate filter in temperature elevation control. At this time, the hydrocarbon injection for the first NOX removal method is performed by the predetermined period at the preset injection pressure. During the time period when the hydrocarbon injection for the first NOX removal method is not being performed, the hydrocarbon injection for the temperature elevation control is performed by an injection pressure which is set lower than the preset injection pressure.

Abstract: The present invention is intended to improve a SOx reduction rate which is a ratio of an amount of SOx reduction with respect to an amount of SOx occlusion in SOx poisoning recovery processing. In the present invention, in the SOx poisoning recovery processing in which the SOx occluded in an NOx storage reduction catalyst is reduced by decreasing the air fuel ratio of an exhaust gas flowing into the NOx storage reduction catalyst to a predetermined air fuel ratio in a repeated manner, the length of a period in which the air fuel ratio of an exhaust gas flowing into the NOx storage reduction catalyst is decreased is made longer in a relatively early time during the processing than in a relatively late time during the processing.

Abstract: The present invention is intended to improve a SOx reduction rate which is a ratio of an amount of SOx reduction with respect to an amount of SOx occlusion in SOx poisoning recovery processing. In the present invention, in the SOx poisoning recovery processing in which the SOx occluded in an NOx storage reduction catalyst is reduced by decreasing the air fuel ratio of an exhaust gas flowing into the NOx storage reduction catalyst to a predetermined air fuel ratio in a repeated manner, the length of a period in which the air fuel ratio of an exhaust gas flowing into the NOx storage reduction catalyst is decreased is made longer in a relatively early time during the processing than in a relatively late time during the processing.