High pressure fuel injection pipe for diesel internal combustion engine

摘要

A fuel injection pipe for a diesel engine which can sustain high internal pressure is provided. The inventive fuel injection pipe of a thick doublet pipe structure comprising an inner pipe and an outer pipe and having a thin inner diameter is arranged such that the inner pipe is formed out of a seam welded pipe made of a high tension steel plate and having a thickness of 0.4 to 1.5 mm and the outer pipe is formed out of a thick steel pipe made of the same material with the inner pipe or of carbon steel. Because the fuel injection pipe thus obtained allows inner facial wrinkles of the inner pipe to be suppressed to 25 mu m or less in depth, it can fully sustain high internal pressure of 1200 bar or more.