Fuel injection control system

摘要

A fuel injection control system for an internal combustion engine comprises a plurality of fuel injector valves, a pumping system having a suction valve, a discharge valve, and a high-pressure pump section sucking fuel into a pressurized chamber with the suction valve opened on a suction stroke and for discharging the fuel in the pressurized chamber toward the injector valves with the discharge valve opened on a discharge stroke. A relief passage is connected, at one end, to a lowpressure line upstream of the suction valve. The other end of the relief passage is connected to the pressurized chamber. A fuel-pressure control valve is disposed in the relief passage for regulating a fuel pressure of the fuel injected from each of the fuel injector valves by opening the fuel-pressure control valve only for a specified time duration from a controllable middle stage of the discharge stroke to the end of the discharge stroke.