Common-rail fuel injection system

1 A common-rail fuel injection system comprising:

• an injector for injecting fuel;
• a flow damper;
• a common rail having a rail main body for accumulating pressure of high-pressure fuel, which is supplied to the injector through the flow damper, wherein the flow damper includes:
• a valve body having a fuel passage therein, wherein:
• one end portion of the fuel passage communicates with the rail main body;
• and
• the other end portion of the fuel passage communicates with the injector;
• and
• a piston that is slidably held in the fuel passage;
• a piston upstream side supply passage, through which fuel flows from a pressure accumulating chamber in the rail main body into the piston;
• a piston upstream side orifice disposed in the piston upstream side supply passage to reduce a cross-sectional area of the piston upstream side supply passage;
• a piston downstream side supply passage, through which fuel flows from the piston into the injector;
• and
• a piston downstream side orifice disposed in the piston downstream side supply passage to reduce a cross-sectional area of the piston downstream side supply passage.