Control method for an exhaust gas purification system and an exhaust gas purification system

A control method for an exhaust gas purifying system, in an internal combustion engine mounted on a vehicle provided with a continuous regeneration DPF device and an exhaust throttle valve in the exhaust gas passage thereof;

• having a DPF control means including;
• a collected quantity detection means for detecting the quantity of collected matters in the continuous regeneration DPF device,
• a travel distance detection means for detecting the travel distance of the vehicle,
• a regeneration timing judgment means for judging the regeneration start timing of the continuous regeneration DPF device,
• an exhaust gas temperature raising means for raising the exhaust gas temperature,
• an unburned fuel supply means for supplying unburned fuel in the exhaust gas,
• a forced regeneration means for regenerating the continuous regeneration DPF device by raising the exhaust gas temperature and forcibly burning the collected matters using the exhaust gas temperature raising means and the unburned fuel supply means,
• a warning means providing a warning urging a driver to stop the vehicle and operate the forced regeneration means, and
• a low collecting quantity-time exhaust gas temperature raising means for raising the exhaust gas temperature through control of fuel injection into the cylinder without Unburned fuel supply control;
• said DPF control means actuating the warning means within a manual regeneration control execution range in which the travel distance detected by the travel distance detection means is not more than a predetermined first judgment travel distance, and in addition, the quantity of collected matters detected by the PM collecting quantity detection means exceeds a predetermined judgment collecting quantity necessary for regeneration;
• automatically executing the forced regeneration means during traveling of the vehicle in both a first automatic traveling regeneration execution range in which a detected travel distance exceeds the predetermined first judgment travel distance and the detected quantity of collected matters exceeds the predetermined judgment collecting quantity, and a second automatic traveling regeneration execution range in which the detected travel distance exceeds a predetermined second judgment travel distance set higher than the predetermined first judgment travel distance;
• and actuating the low collecting quantity-time exhaust gas temperature raising means when the detected travel distance is less than the predetermined second judgment travel distance and the detected quantity of collected matters exceeds a predetermined first judgment quantity of collected matters set lower than the predetermined judgment collecting quantity, and subsequently suspending the actuation of the low collecting quantity-time exhaust gas temperature raising means when the detected quantity of collected matters is less than a predetermined second judgment quantity of collected matters set lower than the predetermined first judgment quantity of collected matters;
• wherein said DPF control means is provided with a vehicle condition detection means for detecting the stationary condition and the traveling condition of the vehicle;
• and continues the actuation of the low collecting quantity-time exhaust gas temperature raising means to close the exhaust throttle valve upon detection of stopping of the vehicle by the vehicle condition detection means during usage of the low collecting quantity-time exhaust gas temperature raising means, subsequently opens the exhaust throttle valve upon re-detection of the vehicle's traveling condition using the vehicle condition detection means, and continues the actuation of the low collecting quantity-time exhaust gas temperature raising means.