Fuel injector with an integrated spark plug for a direct injection type

Abstract

A fuel injector with an integrated spark plug for a direct injection type engine capable of adequate fuel injection and adequate spark discharge, even if it becomes very hot because the end part of device is exposed in a combustion chamber and a spark discharge is induced there. An electric conductor is disposed along the central axis, and the electric conductor is electrically coupled with a cable for supplying electric current for the spark discharge. A needle valve made of conductive material is electrically coupled with the electric conductor through a return spring made of conductive material and is reciprocally moved by a solenoid. A needle housing made of conductive material receives the needle valve and has a nozzle for injecting fuel and a center electrode at its end. A grounding electrode is disposed near the center electrode. Insulators are disposed outside of the electric conductor. Out side of the insulators, an outer cylinder is disposed, which is composed of inner wall which adheres to the insulators and outer wall which is placed outside of the inner wall at a uniform clearance which is used as a fuel passage. A connector assembly for connecting a fuel line and an electric cable for supplying electric current to the solenoid is attached to the outer cylinder.