Abstract: An exhaust gas purification apparatus is provided with: a first soot-accumulation calculation unit 49 which calculates a first soot accumulation amount from an operation state of the engine; a second soot-accumulation calculation unit 51 which calculates a second soot accumulation amount from a total operation time of the engine, a total fuel consumption rate, a pressure difference between front and back of the particulate filter, and the like; a first soot-accumulation correction unit 55 which corrects the first soot accumulation amount calculated by the first soot-accumulation calculation unit 49 to a value greater than the first soot-accumulation amount when the active regeneration starts based on the second soot accumulation amount calculated by the second soot-accumulation calculation unit 51; and a regeneration ending unit 57 which ends the active regeneration when, in such a case that the active regeneration starts based on the corrected soot accumulation amount, the first soot accumulation amount beco

Abstract: A DPF regeneration control device includes: a differential pressure sensor which detects a differential pressure between a front and a rear of a DPF; a DPF differential pressure setting unit which sets a DPF differential pressure generated in accordance with a total accumulated amount of soot and ash, sets a DPF differential pressure generated when an ash accumulation amount corresponds to an accumulation amount at which washing is required, as a washing request threshold, and sets a DPF differential pressure generated when the ash accumulation amount is larger than the washing request threshold such that a reduction in output is necessary, as an output reduction threshold; a washing request issuing unit which determines whether or not the DPF differential pressure has reached the washing request threshold; and an output reduction warning unit which determines whether or not the DPF differential pressure has reached the output reduction threshold.

Abstract: A DPF target temperature setting unit has a temperature increase rate setting portion which sets a temperature increase change rate such that, until a target set temperature at which PM is burnt is reached after the start of late post injection, the temperature increase change rate is reduced in accordance with an increase in temperature or a period of time elapsed since the start of the late post injection, a stepwise temperature increase change rate in the temperature increase rate setting portion includes two stages of a first-stage change rate A and a second-stage change rate B lower than the first-stage change rate, and a target temperature of the DPF temperature is calculated by using the temperature increase rate of the temperature increase rate setting portion.

Abstract: An exhaust gas purification system of engine configured to classify a PM accumulation state of DPF into multiple evaluation stages based on a plurality of evaluation indices, and to repeatedly perform determination of the current evaluation stage by the current stage determination part and determination of whether to move up the current evaluation stage to the evaluation stage of the next rank by the evaluation stage determination part, wherein upon a defect of a sensor among different types of sensors being detected by the defect detection part, the current evaluation stage is newly redetermined by the current stage redetermination part as substituted for the current evaluation stage determined by the current stage determination part.

Abstract: In an exhaust gas treatment method for an internal combustion engine, a DPF abnormal combustion causing operation is determined to have occurred when the internal combustion engine shifts from a high rotation or high load operation region ? to a low rotation, low load operation region ? within a set time T1. When it is determined that a DPF abnormal combustion causing operation has occurred, abnormal combustion of PM collected in the DPF is suppressed by fully opening an intake throttle valve (44) in order to increase an exhaust gas flow so that heat is removed by sensible heat of the exhaust gas, thereby cooling a DPF device (52), and continuing a late post-injection in order to reduce an oxygen concentration of the DPF.

Abstract: The present invention relates to a control unit of an internal combustion engine capable of performing a coordinate control of an exhaust gas recirculation (hereinafter abbreviated as “EGR”) gas supply amount by an EGR apparatus and a supercharging amount by a supercharger provided with a variable flow mechanism. The control unit comprises: a state quantity estimation section for calculating an in-cylinder oxygen excess ratio based on an operating state of the internal combustion engine; and a switching part for switching the respective opening degree commands for the EGR valve and the variable flow mechanism of the supercharger so that the opening degree of the EGR valve and the opening degree of the variable flow mechanism become smaller than in a normal state when the internal combustion engine is determined to be in the transient state based on the calculated in-cylinder oxygen excess ratio.

Abstract: A PM accumulation amount estimation device 50 is provided with an exhaust amount computation means 51 for computing PM exhaust amount which is discharged in an exhaust gas passage 3, and a passive regeneration amount computation means 52 for computing a PM regeneration amount in a DPF 7, and is configured to estimate the PM accumulation amount in the DPF 7 from the difference between the PM exhaust amount computed by the exhaust amount computation means 51 and the PM regeneration amount computed by the passive regeneration amount computation means 52. The PM accumulation amount estimation device 50 is further configured such that, when an abnormality is found in an airflow meter 31, the PM regeneration amount from NO2 is computed, and the PM accumulation amount in the DPF is estimated, without using the airflow amount measured by the airflow meter 31.

Abstract: A DPF target temperature setting unit has a temperature increase rate setting portion which sets a temperature increase change rate such that, until a target set temperature at which PM is burnt is reached after the start of late post injection, the temperature increase change rate is reduced in accordance with an increase in temperature or a period of time elapsed since the start of the late post injection, a stepwise temperature increase change rate in the temperature increase rate setting portion includes two stages of a first-stage change rate A and a second-stage change rate B lower than the first-stage change rate, and a target temperature of the DPF temperature is calculated by using the temperature increase rate of the temperature increase rate setting portion.

Abstract: An exhaust gas purification apparatus for an engine is provided with a filter arranged in an exhaust passage of the engine, and a regeneration control unit for regenerating the filter by burning the particulate matters accumulated in the filter. The control unit may include an over-accumulation state determination unit and a switch. The over-accumulation state determination unit determines over-accumulation of the particulate filter in the filter when the particulate matter is over-accumulated in the filter. The switch switches a regeneration temperature for regenerating the filter between a first regeneration temperature at which a normal regeneration is performed and a second regeneration temperature which is lower than the first regeneration temperature. The control unit is connectable to a command unit when the particular matter is over-accumulated in the filter, so that the switch is forcibly operated toward the second regeneration temperature.

Abstract: An exhaust gas emission control system for a diesel engine, having an oxidation catalyst (DOC) (7) and a diesel particulate filter (DPF) (9) in an exhaust passage, wherein a late post-injection control unit (62), which injects fuel into a combustion chamber at a timing not contributing to combustion in DPF regeneration control, feedback controls a late post-injection amount such that a regeneration amount of soot regenerated by the DPF (9) becomes a target soot regeneration amount.

Abstract: A DPF regeneration control device includes: a differential pressure sensor which detects a differential pressure between a front and a rear of a DPF; a DPF differential pressure setting unit which sets a DPF differential pressure generated in accordance with a total accumulated amount of soot and ash, sets a DPF differential pressure generated when an ash accumulation amount corresponds to an accumulation amount at which washing is required, as a washing request threshold, and sets a DPF differential pressure generated when the ash accumulation amount is larger than the washing request threshold such that a reduction in output is necessary, as an output reduction threshold; a washing request issuing unit which determines whether or not the DPF differential pressure has reached the washing request threshold; and an output reduction warning unit which determines whether or not the DPF differential pressure has reached the output reduction threshold.

Abstract: An exhaust gas purification apparatus is provided with: a first soot-accumulation calculation unit 49 which calculates a first soot accumulation amount from an operation state of the engine; a second soot-accumulation calculation unit 51 which calculates a second soot accumulation amount from a total operation time of the engine, a total fuel consumption rate, a pressure difference between front and back of the particulate filter, and the like; a first soot-accumulation correction unit 55 which corrects the first soot accumulation amount calculated by the first soot-accumulation calculation unit 49 to a value greater than the first soot-accumulation amount when the active regeneration starts based on the second soot accumulation amount calculated by the second soot-accumulation calculation unit 51; and a regeneration ending unit 57 which ends the active regeneration when, in such a case that the active regeneration starts based on the corrected soot accumulation amount, the first soot accumulation amount beco

Abstract: An exhaust gas purification apparatus for an engine is provided with a filter arranged in an exhaust passage of the engine, and a regeneration control unit for regenerating the filter by burning the particulate matters accumulated in the filter. The control unit may include an over-accumulation state determination unit and a switch. The over-accumulation state determination unit determines over-accumulation of the particulate filter in the filter when the particulate matter is over-accumulated in the filter. The switch switches a regeneration temperature for regenerating the filter between a first regeneration temperature at which a normal regeneration is performed and a second regeneration temperature which is lower than the first regeneration temperature. The control unit is connectable to a command unit when the particular matter is over-accumulated in the filter, so that the switch is forcibly operated toward the second regeneration temperature.

Abstract: In an exhaust gas treatment device in which a diesel oxidation catalyst and a DPF are provided in an exhaust pipe of an internal combustion engine, abnormal combustion in the DPF, occurring when the internal combustion engine varies from a high load condition to a low load condition, poses a problem. To solve this problem, in the present invention, a DPF abnormal combustion causing operation is determined to have occurred when the internal combustion engine shifts from a high rotation or high load operation region ? to a low rotation, low load operation region ? within a set time T1. When it is determined that a DPF abnormal combustion causing operation has occurred, abnormal combustion of PM collected in the DPF is suppressed by fully opening an intake throttle valve 44 in order to increase an exhaust gas flow so that heat is removed by sensible heat of the exhaust gas, thereby cooling a DPF device 52, and continuing a late post-injection in order to reduce an oxygen concentration of the DPF.

Abstract: A control device of a control valve used for an intake air-gas system of an engine, the device including, but not limited to: the control valve which is an intake air throttle valve provided in the intake air-gas system provided in the intake air-gas system of the engine to control the flow rate of intake air to the engine, or an EGR valve provided in the intake air-gas system of the engine to control the flow rate of EGR gas to the engine; and a control unit which determines a target opening of the control valve in response to the operation conditions of the engine, and controls the opening of the control valve so that the opening conforms with the target opening, wherein the control unit is configured so that, in a case where the target opening is maintained at a same level during over a fixed duration, the target opening is changed, in time, from the target opening which is determined in response to the operation conditions of the engine and controls the opening of the control valve, in order to prevent th