Centrifugal compressor and turbocharger including the same

A centrifugal compressor comprising:

• an impeller;
• and
• a housing having a scroll passage of spiral shape formed on an outer peripheral side of the impeller, wherein, when a circumferential-directional position of the scroll passage is represented by an angular position with respect to a scroll end of the scroll passage, and in a cross-section obtained by cutting the scroll passage along a plane including a rotational axis of the impeller at a circumferential-directional position where the angular position is θ, F(θ) is defined as:
• F(θ)=(A/R)/r,
• where A is a cross-sectional area of the scroll passage, R is a distance from the rotational axis to a scroll center of the cross-section of the scroll passage, and r is a radius of the impeller,
• 0.35≤F(360°)≤0.65, and
• 0.08×F(360°)≤F(60°)≤0.4×F(360°),
• wherein, when a reference change rate Δ which is a change rate of F(θ) in a range of θ from 60° to 360° is defined as:
• Δ=[F(360°)=F(60°)]/(360°−60°),
• the scroll passage includes a first region where F(θ) changes at a smaller change rate than the reference change rate at least partially in a range of θ from 60° to 270°, and
• wherein the first region includes:
• a change rate decreasing region where the change rate of F(θ) decreases;
• and
• a change rate increasing region, downstream of the change rate decreasing region, where the change rate of F(θ) increases.