PROBLEM TO BE SOLVED : To propose a

PROBLEM TO BE SOLVED : To propose a common rail and a fuel injection system, which can improve, with a simpler configuration, pressure increasing performance at the time of engine starting and pressure fluctuation suppressing performance during engine operation. SOLUTION : A common rail (20) for supplying fuel to injectors (21) is divided into a main rail (201) and a sub rail (202), and a check valve (203) is disposed between the main rail (201) and the sub rail (202). The check valve (203) adjusts the volume of the whole common rail (20) by closing so that the fuel does not flow out from the main rail (201) toward the sub rail (202) when the pressure in the main rail (201) is equal to or less than a predetermined reference pressure and by opening so that the fuel flows out from the main rail (201) toward the sub rail (202) when the pressure in the main rail (201) becomes larger than the predetermined reference pressure. SELECTED DRAWING : Figure 2 COPYRIGHT : (C)2020, JPO&INPIT