| 摘要 |
PURPOSE:To attain the stable control of flow rate even in case the number of working pumps is changed by obtaining the control output time width and the control output pause time width in order to give the intermittent control to a discharge valve having a selected short target arriving time. CONSTITUTION:In case the number of working pumps is changed, a comparison is carried out between a period of time during which the opening amount of a discharge valve that is operated continuously is coincident with the target opening amount of the discharge valve set after the number of working pumps is changed and a period during which a discharge valve of a pump to be operated newly reaches said target opening amount or a period during which the discharge valve of a pump whose operation is stopped is closed. Thus the discharge valve having the shorter time to reach the target opening amount is selected. At the same time, the difference is obtained between both reaching times. Then the control output time width is obtained from the selected reaching time of the discharge valve and the intermittent control times set previously. While the control output puase time width is obtained from said time difference and intermittent control times. Then the intermittent control is given to the discharge valve having the selected short reaching time. In this way, a big variation of the total discharge amount is prevented. |
