Abstract: An exhaust gas purification device includes an exhaust gas after-treatment device provided in an exhaust passage of an internal combustion engine, and has an oxidation catalyst and a DPF or diesel particulate filter. The exhaust gas purification device also includes an exhaust pipe injector which feeds a fuel to the oxidation catalyst, and a control unit which controls regeneration of the filter by supplying the oxidation catalyst with the fuel from the exhaust pipe injector. The control unit determines whether the filter is in a regeneration-possible state, i.e., whether the oxidation catalyst is maintained at a high temperature allowing regeneration of the filter. If the control unit determines during regeneration control of the filter that the filter is not in the regeneration-possible state, then the control unit halts the regeneration control until the regeneration-possible state is reached.

Abstract: In the exhaust gas purification system, a diesel particulate defuser (“DPD”) for trapping particulate matter (“PM”) in exhaust gas is connected to an exhaust pipe of an engine to automatically regenerate the DPD by raising a temperature of the exhaust gas from the engine by carrying out post injection when an amount of PM in the DPD exceeds a predetermined amount. Further, the system includes detecting the temperature of the exhaust gas during DPD regeneration when the DPD is automatically regenerated, calculating a deviation between the detected temperature of the exhaust gas and a target temperature for the DPD regeneration, and controlling a quantity of the post injection by resetting an integral control term used in a PID control to zero when running mode automatic regeneration is shifted to idling mode automatic regeneration after a vehicle is stopped, when PID-controlling the quantity of the post injection based on the deviation.

Abstract: An exhaust pipe injection control device to optimally control a degree of exhaust gas recirculation (“EGR”) opening during diesel particulate filter (“DPF”) regeneration. The device includes a regeneration-time opening control unit which controls a degree of EGR opening of an EGR device during DPF regeneration, and a regeneration-time opening map in which an optimal degree of EGR opening of the EGR device during DPF regeneration is set in advance according to an engine rotation speed and a fuel injection amount of an engine. The regeneration-time opening control unit performs exhaust gas recirculation by referring to the regeneration-time opening map based on the engine rotation speed and the fuel injection amount of the engine and controlling the degree of EGR opening of the EGR device.

Abstract: An exhaust gas purification device includes an exhaust gas after-treatment device provided in an exhaust passage of an internal combustion engine, and has an oxidation catalyst and a DPF or diesel particulate filter. The exhaust gas purification device also includes an exhaust pipe injector which feeds a fuel to the oxidation catalyst, and a control unit which controls regeneration of the filter by supplying the oxidation catalyst with the fuel from the exhaust pipe injector. The control unit determines whether the filter is in a regeneration-possible state, i.e., whether the oxidation catalyst is maintained at a high temperature allowing regeneration of the filter. If the control unit determines during regeneration control of the filter that the filter is not in the regeneration-possible state, then the control unit halts the regeneration control until the regeneration-possible state is reached.

Abstract: An exhaust pipe injection control device to optimally control a degree of exhaust gas recirculation (“EGR”) opening during diesel particulate filter (“DPF”) regeneration. The device includes a regeneration-time opening control unit which controls a degree of EGR opening of an EGR device during DPF regeneration, and a regeneration-time opening map in which an optimal degree of EGR opening of the EGR device during DPF regeneration is set in advance according to an engine rotation speed and a fuel injection amount of an engine. The regeneration-time opening control unit performs exhaust gas recirculation by referring to the regeneration-time opening map based on the engine rotation speed and the fuel injection amount of the engine and controlling the degree of EGR opening of the EGR device.

Abstract: In the exhaust gas purification system, a diesel particulate defuser (“DPD”) for trapping particulate matter (“PM”) in exhaust gas is connected to an exhaust pipe of an engine to automatically regenerate the DPD by raising a temperature of the exhaust gas from the engine by carrying out post injection when an amount of PM in the DPD exceeds a predetermined amount. Further, the system includes detecting the temperature of the exhaust gas during DPD regeneration when the DPD is automatically regenerated, calculating a deviation between the detected temperature of the exhaust gas and a target temperature for the DPD regeneration, and controlling a quantity of the post injection by resetting an integral control term used in a PID control to zero when running mode automatic regeneration is shifted to idling mode automatic regeneration after a vehicle is stopped, when PID-controlling the quantity of the post injection based on the deviation.