Fuel pressure control device for high pressure fuel injection system

摘要

The present invention proposes a fuel pressure control apparatus and method for a high-pressure fuel injection system which sufficiently reduces a fuel pressure in an accumulator line while preventing the high-pressure fuel injection system from being adversely affected. The fuel pressure control apparatus for the high-pressure fuel injection system is equipped with an accumulator line for accumulating fuel supplied from a fuel pump at a high pressure and supplying the fuel to fuel injection valves, and with a relief valve for discharging fuel in the accumulator line. Furthermore, the apparatus is equipped with fuel pressure control means for detecting a fuel pressure in the accumulator line and driving the relief valve so as to reduce the fuel pressure in accordance with a pressure reduction requirement based on a comparison between the detected fuel pressure and a target pressure. The fuel pressure control means controls an opening movement of the relief valve such that the open-valve period of the relief valve does not overlap with an open-valve period of the fuel injection valves, a timing for detecting fuel pressure, a period for force-feeding fuel from the fuel pump or the like.