| 摘要 |
PURPOSE:To improve the regeneration efficiency of an exhaust gas filter by estimating an exhaust gas temp. from the output signals of an exhaust gas temp. sensor and the rack position sensor of a fuel injection pump to control an EGR valve, and keeping an exhaust gas temp. to the optimum. CONSTITUTION:When a vehicle is traveling, first, whether the detected value of the pressure of exhaust gas by an exhaust pressure sensor 34 gets above an allowable value or not is judged by a control means 24. And, when judged yes while also detecting that the vehicle is traveling on an expressway with its vehicle speed by a vehicle speed sensor 26 being above a set value, it is judged whether an exhaust gas temp. by a temp. sensor 28 is above a defined value (approx. 400 deg.C) or not. When judged no, a butterfly valve 18 is closed to increase the exhaust gas temp. When judged yes, on the other hand, a timer is driven and an EGR valve 20 is controlled over a set time to obtain a defined value of an EGR ratio, and the exhaust gas temp. is maintained at the temp. (approx. 600 deg.C-700 deg.C) necessary for the regeneration of a particulate filter 12. |
