Fuel injection valve

A fuel injection valve comprising:

• an injection hole body having an injection hole configured to inject fuel;
• a valve body having a seat surface configured to be separated from and seated on a seating surface of the injection hole body;
• and
• a fuel passage between the injection hole body and the valve body, the fuel passage configured to communicate with an inflow port of the injection hole and configured to be opened and closed due to separation and seating of the valve body, wherein
• the seat surface is curved and is swollen toward the seating surface,
• in a seat portion throttle state, a flow rate of the fuel injected from the injection hole is restricted to a flow rate throttled by a gap between the seat surface and the seating surface,
• in an injection hole throttle state, the flow rate of the fuel is restricted to a flow rate throttled by the injection hole,
• when the valve body is operated to be opened from a valve closing position to a full lift position, the seat portion throttle state is brought from the valve closing position to a predetermined intermediate position, and the injection hole throttle state is brought from the intermediate position to the full lift position,
• a passage sectional area of an inter-seat-injection-hole gap that is a portion of the fuel passage on the downstream side of the seating surface is an inter-seat-injection-hole passage sectional area,
• a passage sectional area of the injection hole is an injection hole passage sectional area, and
• in a valve closed state in which the valve body is seated on the injection hole body, the inter-seat-injection-hole passage sectional area is smaller than the injection hole passage sectional area.