Patent ID: 6536413
Filing Date: 2003-03-25
Classification: F02M,Y10T

Abstract:
An accumulator fuel injection apparatus for an internal combustion engine having an accumulator for storing high-pressure fuel delivered from a high-pressure fuel feed pump, and additionally, a pressure safety valve that opens when accumulator pressure has exceeded a predetermined value to lower the accumulator pressure below an excessive pressure, the pressure safety valve comprising:a valve body having a valve hole, the valve body having a sliding bore formed on a downstream side of the valve hole; a valve element axially movably positioned in the valve body to open and close the valve hole; a piston having a small-diameter portion axially slidably supported in the sliding bore on a valve element side by the valve body, the piston having a large diameter portion which has a larger outside diameter than the small-diameter portion on an opposite side of the valve element, the piston being engaged with the valve element to axially move as one body together with the valve element; a spring for pressing the valve element through the piston with a predetermined force in a direction toward closing the valve hole; and a damper chamber located downstream of the sliding bore in the valve body and housing the large diameter portion of the piston together with fuel; wherein the damper chamber is a recessed portion of the value body of having a larger inside diameter than the sliding bore, having an opening in an end face on the spring side of the valve body, and being defined by the end face of the large diameter portion of the piston on the sliding bore side, an inner wall surface of the recessed portion and a stepped portion between the recessed portion and the sliding bore; wherein the large diameter portion of the piston and the recessed portion of the valve body are disposed so that the large diameter portion of the piston exits the recessed portion of the valve body when the piston moves beyond a predetermined value.