Exhaust gas purification device, exhaust gas purification method, and control device

An exhaust gas purification method that is a control method of an exhaust gas purification device including

• a throttle valve configured to be provided in a path through which an exhaust gas discharged from an engine flows, a rotational speed of the engine being controlled in accordance with an operation of an accelerator,
• a diesel oxidation catalyst device configured to be disposed on a downstream side of the throttle valve;
• a selective reduction catalyst device configured to be disposed on a downstream side of the diesel oxidation catalyst device,
• a fuel injection device configured to inject fuel on an upstream side of the diesel oxidation catalyst device;
• an inlet temperature sensor configured to measure an inlet temperature of the diesel oxidation catalyst device,
• an outlet temperature sensor configured to measure an outlet temperature of the diesel oxidation catalyst device, and
• a control device configured to input temperature data measured by the inlet temperature sensor and the outlet temperature sensor and control the throttle valve and the fuel injection device, the exhaust gas purification method comprising:
• changing, in a case of performing control of throttling the throttle valve, an upper limit value of a valve openness when a fully closed condition of the throttle valve is set as a maximum value of the valve openness and a fully open condition of the throttle valve is set as a minimum of the valve openness, based on a determination result based on an accelerator openness of the accelerator and operation conditions of one or more operation devices different from the accelerator.

A control device in an exhaust gas purification device including

• a throttle valve configured to be provided in a path through which an exhaust gas discharged from an engine flows, a rotational speed of the engine being controlled in accordance with an operation of an accelerator,
• a diesel oxidation catalyst device configured to be disposed on a downstream side of the throttle valve;
• a selective reduction catalyst device configured to be disposed on a downstream side of the diesel oxidation catalyst device,
• a fuel injection device configured to inject fuel on an upstream side of the diesel oxidation catalyst device;
• an inlet temperature sensor configured to measure an inlet temperature of the diesel oxidation catalyst device, and
• an outlet temperature sensor configured to measure an outlet temperature of the diesel oxidation catalyst device,
• wherein the control device inputs temperature data measured by the inlet temperature sensor and the outlet temperature sensor and controls the throttle valve and the fuel injection device, and
• in a case of performing control of throttling the throttle valve, the control device changes an upper limit value of a valve openness when a fully closed condition of the throttle valve is set as a maximum value of the valve openness and a fully open condition of the throttle valve is set as a minimum of the valve openness, based on a determination result based on an accelerator openness of the accelerator and operation conditions of one or more operation devices different from the accelerator.