Patent ID: 6446608
Filing Date: 2002-09-10
Classification: F02M

Abstract:
An injection device for an internal combustion engine using direct injection, comprising:an actuator; a piston connected to said actuator; an injection device body having a pressure chamber formed therein and a high-pressure line communicating with said pressure chamber; an injection nozzle disposed in a nozzle chamber formed in said injection device body and communicating with a fuel supply line; a pressure-relief valve disposed to communicate with said high-pressure line and to draw a constant volume of fuel from said high-pressure line before closing; said pressure-relief valve having a piston movably disposed in a cylindrical bore; said bore having a first portion with a larger inner diameter and a second portion with a smaller inner diameter, and a conical step transition from the larger inner diameter to the smaller inner diameter; and said piston having an upper, conically expanding segment and a ring segment below said upper segment, said ring segment sealing against an inner wall surface bounding said second portion of said bore, and during a downward movement of said piston, said conically expanding segment coming to be seated on said step transition.