FUEL INJECTION DEVICE AND ENGINE

摘要

PROBLEM TO BE SOLVED: To improve operation accuracy of a fuel injection valve by curbing temperature fluctuation of hydraulic oil.SOLUTION: A fuel injection device 128 comprises: a hydraulic pump which discharges hydraulic oil; a casing 146 provided with a hydraulic chamber 174 connected to the hydraulic pump; a working piston 172 which is slidably installed in the casing, held at a standby position to maintain a fuel injection valve 160 in a closed state when pressure inside the hydraulic chamber is less than a predetermined threshold and moved to a working position to put the fuel injection valve into an open state when the pressure inside the hydraulic chamber is not less than the threshold; and a bypass hole 180 which is provided on the working piston to guide the hydraulic oil discharged from the hydraulic pump into the hydraulic chamber while the working piston is held at the standby position or to discharge the hydraulic oil guided from the hydraulic pump into the hydraulic chamber out of the same.SELECTED DRAWING: Figure 3