| 摘要 |
<p>PURPOSE:To accomplish smooth recirculation of exhaust gas without causing deterioration in engine performance, by making the value of exhaust-gas recirculation lower than a requirement value at the time when engine temperature becomes higher than a value preset for stopping recirculation of exhaust gas, and increasing the value of exhaust-gas recirculation as a function of engine temperature. CONSTITUTION:There is provided a control unit 13 which opens and closes EGR- valve 4 by processing various inputs 12 given during engine operation and thereby controlling actuator 10 consisting of a constant pressure valve and a pulse electromagnetic valve 25. The control unit 13 detects the temperature of engine cooling water by water-temperature sensor 19 and memorizes a requirement value of exhaust-gas recirculation, for instance, at 80 deg.C to the engine speed and fuel pulse width per quantity of intake air. When water temperature is raised from a certain low value, for instance, 35 deg.C at which it is designed to stop recirculation of exhaust gas to a value higher than 35 deg.C, the amount of exhaust gas to be recirculated is made smaller than said requirement value for exhaust-gas recirculation at the time when water temperature is 80 deg.C, and increased gradually as a function of engine temperature.</p> |
