INTAKE MANIFOLD FOR INTERNAL COMBUSTION ENGINE

摘要

An air-intake manifold includes a plurality of air-intake pipes connecting between a collector and an air-intake pipe mount. Each air-intake pipe 3 is bent to have a predetermined shape. Each air-intake pipe 3 is fabricated by bending a substantially straight double metal pipe that has an outer pipe 3a and an inner pipe 3b with a clearance 3c therebetween equal to or less than 0.2 mm, such that the outer pipe 3a and the inner pipe 3b locally contact with each other at an intermediate region. Accordingly, while the outer pipe 3a and the inner pipe 3b of the air-intake pipe 3 locally contact with each other at the contact point 3e (in the relatively slidable relationship), an air layer having a thickness equal to or less than about 0.2 mm is formed between the outer pipe 3a and the inner pipe 3b at portions except for the contact point 3e.