TERMINAL STRUCTURE OF HIGH-PRESSURE FUEL PIPE FOR DIRECT INJECTION ENGINE

摘要

Provided is a terminal structure of a high-pressure fuel pipe for a direct injection engine which can prevent stress concentration to a brazed portion between a pipe and a connection part effectively. In the terminal structure of a high-pressure fuel pipe for a direct injection engine where a connection head is brazed to an end of a fuel pipe, the end of the fuel pipe continued to a fuel pipe insertion portion of the connection head is provided with a drawn portion, an outer diameter D1 of the drawn portion to a fuel pipe diameter D satisfies 0.8D≦D1≦0.9D, and a length L1 of the drawn portion having the outer diameter D1 in a pipe-axial direction from an end of the fuel pipe insertion portion satisfies L1≧0.06D.

主权项

1. A terminal structure of a high-pressure fuel pipe for a direct injection engine, comprising: a connection head brazed to an end of a steel or stainless steel fuel pipe the connection head having a spherical or a curved-face pressing seat face at a distal end thereof and a fuel pipe insertion portion on an end opposite the pressing seat face,
wherein the end of the fuel pipe continued from the fuel pipe insertion portion of the connection head is provided with a one-stage drawn portion, an outer diameter D1 of the drawn portion relative to a fuel pipe diameter D satisfying 0.8D≦D1≦0.9D, and wherein a length L1 of the drawn portion having the outer diameter D1 from an end of the fuel pipe insertion portion in an axial direction of the pipe satisfies L1≧0.06D.