Compressor housing

A compressor housing of a compressor that uses an impeller provided in an intake air flow path of an internal combustion engine of a vehicle more to a downstream side than a blow-by gas recirculation part in which blow-by gas of the internal combustion engine recirculates, to pressurize intake air flowing through the intake air flow path, the compressor housing comprising:

• an impeller chamber that houses the impeller to be rotatable, and an intake air duct that extends along an axis line of the impeller and introduces intake air to the impeller chamber, and
• a breather duct that extends in the radial direction of the impeller and introduces blow-by gas into the intake air duct,
• wherein the intake air duct includes an inner-wall face that connects with an intake air inlet formed in the impeller chamber,
• wherein a step part that is arc shaped along a circumferential direction of the impeller and has a distance along the radial direction of the impeller from the axis line that is farther at a downstream side than at an upstream side thereof is formed in the inner-wall face more to an upstream side along the axis line than the intake air inlet,
• wherein a blow-by gas inlet connecting an inner circumferential face of the breather duct and the inner-wall face is provided vertically above the intake air inlet in a state where the compressor housing is mounted on the vehicle, and
• wherein the blow-by gas inlet is provided in the intake air flow path more to a downstream side than the step part.