Air intake device of engine with supercharger

An air intake device of an engine, the engine comprising:

• an engine body;
• an air intake passage which introduces intake air into the engine body;
• and
• a supercharger which includes a compressor disposed in the air intake passage and supercharges the intake air,
• the air intake device comprising:
• a bypass passage which makes a portion of the air intake passage on an upstream side of the compressor and a portion of the air intake passage on a downstream side of the compressor communicate with each other thus bypassing the compressor;
• and
• a bypass passage open/close valve which opens or closes the bypass passage, wherein
• the air intake passage has an upstream-side pipe positioned upstream of the compressor,
• the upstream-side pipe includes a first passage extending toward an upstream side from the compressor along a first direction, a bent portion bent from an upstream end of the first passage in a second direction, which differs from the first direction, and a second passage extending from an upstream end of the bent portion along the second direction,
• the bypass passage is connected to a connecting portion mounted in the first passage,
• the second passage has a vertically elongated cross-sectional shape where a size of the second passage in a vertical direction is larger than a size of the second passage in a width direction,
• a vibration suppressing support fin suppressing vibrations of the second passage is disposed in at least one of the bent portion and the second passage,
• a vibration damping material which is disposed on a surface of at least one of the second passage and the bent portion and is configured to function as the vibration suppressing support fin by absorbing vibrations of the surface,
• a wall thickness of the upstream-side pipe is set such that the wall thickness of a specified portion which includes at least a portion of a side wall of the bent portion on an outer peripheral side having a small curvature is smaller than wall thicknesses of other portions, and
• the vibration damping material is disposed on the surface of the specified portion.