| 摘要 |
PURPOSE:To allow high-frequency control with a simple structure by providing a mechanism controlling the needle set load of an injection valve to change the opening force as an injection rate control means in a fuel injection device containing a spool valve using a piezoelectric element as a drive source. CONSTITUTION:A fuel injection section 6 is constituted with an injection control section 5 and an injection valve 4, and the injection control section 5 is constituted with a piezoelectric element drive spool valve 2 and a solenoid valve 3. The spool valve 2 is constituted of a spool 11 having a taper seal 10 opening/ closing and controlling the passage of the high-pressure fuel fed from a high- pressure fuel port Ps, a piezoelectric element 12 serving as the drive source of the spool 11, and a spool return spring 13. The solenoid valve 3 provided to control the pressure Pc of a pressure chamber 18 where the needle return spring 17 of the injection valve 4 is arranged, and this pressure Pc is controlled by adjusting the contraction quantity of a variable orifice 19 in the drain passage branched from the passage guided from the high-pressure fuel port Ps, i.e., the displacement of a solenoid valve poppet 20.
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