FUEL INJECTION DEVICE

PROBLEM TO BE SOLVED: To enhance exhaust gas performance and engine performance by arranging a valve device which opens a fuel discharge passage by an always closed type constant pressure valve when fuel pressure is a second preset pressure higher than a first preset pressure and opens and closes the fuel discharge passage downstream of its constant pressure valve according to an engine operating condition. SOLUTION: A fuel passage 36 whose one end is communicated with a fuel reservoir 22 and other end is communicated with a fuel injection pump, is arranged in a valve housing, and the upstream end of its one end of a fuel discharge passage 38 to communicate the lower end of its one end with a leak-off passage of the fuel injection pumps is connected to the fuel reservoir 22. An always closed type constant pressure valve 40 is interposed in its fuel discharge passage 38, and its constant pressure valve 40 is opens the fuel discharge passage 38 when the fuel pressure is the second preset pressure higher than the first preset pressure. A valve device 46 is interposed in the fuel discharge passage 38 downstream of the constant pressure valve 40, and its valve device 46 opens and closes the fuel discharge passage 38 according to an engine operating condition. Therefore, low pressure injection can be effectively performed prior to main injection.