Fuel injector and internal combustion engine

摘要

The present invention provides a simplified fuel injector which uses fuel as hydraulic oil to intensify the injection pressure. A pressure intensifier of the fuel injector is provided with a pressurization piston 106, a first fuel chamber 107 that communicates with a fuel inlet passage 101 (or a fuel supply passage), and a fuel pressurization chamber 111. The pressurization chamber 111 is provided inside a valve body 110. The pressurization piston 106 is formed displaceably relative to the valve body 110 and is provided with a first pressure receiving surface 106a and a pressurization piston portion 106b. The first pressure receiving surface 106a is one end surface of the pressurization piston 106 which faces one of the piston displacement directions 106d, that is, faces the first fuel chamber 107. The pressurization piston portion 106b is provided on the other end surface of the piston 106 which faces the other direction of the piston displacement directions 106d, that is, faces the pressurization chamber 111. The area of the pressurization piston portion 106b which faces the pressurization chamber 111 is smaller than that of the first pressure receiving surface 106a, and the pressurization piston portion 106b serves to change the volume of the pressurization chamber 111.