Patent ID: 6959883
Filing Date: 2005-11-01
Classification: F02M

Abstract:
1. A fuel injection valve comprising: a housing constituting a main body of the fuel injection valve; a nozzle chamber and a coil chamber which are provided in the housing; a sack which is provided at one end portion of the nozzle chamber; a nozzle which is provided in a peripheral surface of the sack; a slide portion which is provided so as to connect the nozzle chamber to the coil chamber; a needle which extends from the nozzle chamber to the coil chamber through the slide portion, and which is supported in the slide portion so as to be slidable in a longitudinal axis direction; a pressurized fuel source which is connected to the nozzle chamber, and which supplies pressurized fuel to the nozzle chamber so that the nozzle chamber is filled with the pressurized fuel; a solenoid coil which is fixed in the coil chamber; an armature which is provided on the needle at a portion positioned in the coil chamber such that the armature is opposed to the solenoid coil; a compression spring which is inserted between an inner wall surface of the housing and an outer surface of the needle so as to apply force to the needle in a valve closing direction; and a needle seat which is provided in a vicinity of the nozzle, wherein: when the needle is seated at the needle seat in the vicinity of the nozzle, an annular seal is formed between the needle and the needle seat; the fuel injection valve includes a bottom portion side extending portion that extends in the longitudinal axis direction from a needle bottom surface inner portion, which is a portion of a bottom surface of the needle on an inner side of the annular seal, into the sack beyond the nozzle chamber; when the needle is seated at the needle seat, upward pressure of the pressurized fuel is applied only to a downward pressure receiving surface outer portion that is an annular portion of a downward pressure receiving surface on an outer side of the annular seal, the downward pressure receiving surface being formed in the needle at a portion positioned in the nozzle chamber; and when the needle is separated from the needle seat, the upward pressure of the pressurized fuel is applied to an entire portion of the downward pressure receiving surface, the entire portion excluding a cross sectional area of the bottom portion side extending portion.