Vehicle air duct for reducing intake noise

An air duct for a vehicle having a function of reducing intake noise, the air duct comprising:

• an outer housing configured having a pipe shape to introduce outside air therethrough into an engine;
• and
• an inner pipe in the outer housing and configured so that an outer surface of the inner pipe is spaced apart from an inner surface of the outer housing, thereby partitioning the inside of the outer housing in a radial direction,
• wherein a space between the inner pipe and the outer housing communicates with the inside of the inner pipe,
• wherein partition walls extend from the inner pipe toward the outer housing, the partition walls defining portions at which the inner pipe is fixed to the outer housing,
• wherein the partition walls are disposed at plural at positions spaced apart from each other,
• wherein, among the partition walls, a front partition wall is formed at a side of the air duct at which the air is introduced, and wherein the front partition wall extends from a front end of the inner pipe in a radial direction,
• wherein, among the partition walls, a rear partition wall is spaced apart from the front partition wall,
• wherein assembly grooves are formed in the inner surface of the outer housing to accommodate the circumferential outer edges of the partition walls,
• wherein a rear assembly groove that accommodates the rear partition wall is formed in the inner surface of the outer housing at a predetermined position where the rear partition wall is positioned,
• wherein the rear assembly grooves are formed in plural to accommodate a case in which the rear partition wall is changed as the engine displacement is changed,
• wherein the rear partition wall is positioned spaced apart from a rear end of the inner pipe by a predetermined distance,
• wherein, the inner pipe is extended rearward from the rear partition wall,
• wherein a chamber for resonance is configured by the inner pipe, the outer housing and the rear partition wall, and the chamber is opened toward the engine,
• wherein the predetermined distance between the rear end of the inner pipe and the rear partition wall is greater than a gap between the inner pipe and the outer housing,
• wherein the predetermined distance between the rear end of the inner pipe and the rear partition wall is greater than a diameter of the inner pipe,
• wherein the inner pipe and the outer housing are of sufficient length and bent between the rear partition wall and the rear ends of the inner pipe and the outer housing,
• wherein a hole is formed through the inner pipe and provides air flow communication between the space defined within the inner pipe and the outer housing and the inside of the inner pipe, and
• wherein the hole is formed between the front partition wall and the rear partition wall, and is formed having a neck surrounding the hole and extending from the inner pipe toward the outer housing at a predetermined length.