A fuel injection device configured to inject fuel from an injection hole toward a combustion chamber, the fuel injection device comprising:
- a valve body having the injection hole, a pressure control chamber configured to be filled with fuel, an inflow passage configured to allow fuel to flow into the pressure control chamber, and an outflow passage configured to allow fuel to flow out of the pressure control chamber, in which an inflow opening portion of the inflow passage and an outflow opening portion of the outflow passage are opened in an opening wall defining the pressure control chamber;
- a nozzle needle configured to be displaced relative to the valve body according to a variation in the fuel pressure in the pressure control chamber to open and close the nozzle hole;
- a valve mechanism that partitions the pressure control chamber into an upper control chamber portion, which faces the outflow opening portion, and a lower control chamber portion, and has at least one communication passage which communicates the upper control chamber portion with the lower control chamber portion, the valve mechanism configured to open and close the outflow opening portion and the inflow opening portion and to switch a flow channel area of the communication passage;
- and
- a drive unit configured to drive the valve mechanism and to increase and decrease an input drive energy, wherein
- the valve mechanism includes:
- a first control valve body configured to be seated on and unseated from the opening wall by the drive of the drive unit and to open or close the outflow opening portion;
- a hydraulically actuated valve body slidable on an outer peripheral surface of the first control valve body, the hydraulically actuated valve body configured to be seated on and unseated from the opening wall by a pressure difference generated between the upper control chamber portion and the lower control chamber portion and to open or close the inflow opening portion;
- and
- a second control valve body configured to be seated on and unseated from the hydraulically actuated valve body while being driven by the drive unit via the first control valve body and to switch the communication passage from a first throttle state to a second throttle state larger in flow channel area than the first throttle state, wherein
- the hydraulically actuated valve body is configured to close the inflow opening portion by a force received from the fuel in the lower control chamber portion due to a communication between the upper control chamber portion and the outflow passage by unseating the first control valve body,
- the communication passage is configured to control an outflow flow rate of the fuel from the lower control chamber portion to the outflow passage in a state where the hydraulically actuated valve body closes the inflow opening portion,
- the drive unit is configured
- to receive a first drive energy to cause the first control valve body to be unseated from the opening wall while maintaining the seating of the second control valve body on the hydraulically actuated valve body and
- to cause the fuel to flow from the lower control chamber portion to the outflow passage through the communication passage in the first throttle state, and
- the drive unit is configured
- to receive a second drive energy larger than the first drive energy to cause both of the first control valve body and the second control valve body to be unseated and
- to cause the fuel to flow from the lower control chamber portion to the outflow passage through the communication passage in the second throttle state.