| 摘要 |
PURPOSE:To enable the prompt discharge of accurate, stable and most appropriate common rail pressure with low driving energy even under hard conditions such as a low-speed driving time by controlling the pressure applying/force-feeding starting time and discharge of fuel by means of an outer-open type solenoid valve. CONSTITUTION:A variable discharge high-pressure pump, as its cam speed reaches its peak in the first half of the rising stroke of a plunger, reaches a certain extent of cam acceleration already at a control starting time as well as the rise of the plunger is accelerated to be high in speed. Accordingly, the pressure in a pump chamber can be made high enough, in the short initial rising time of the plunger, to maintain a closed outer-open type solenoid valve in the closed state. As a result, although a valve closing designating time T0 is set short in order to enable the sufficient operation of the variable discharge high-pressure pump even at a high speed driving time, the pump pressure enough to maintain the closed state of the valve within the short valve closing designating time T0 can be ensured, so that force-feeding can be continued until the plunger reaches its top dead center even after the valve opening is authorized in a short time, and thus high-volume discharge can be ensured even at a low speed driving time. |
