Variable-geometry Turbocharger - Most Common Designs

Most Common Designs

The two most common implementations include a ring of aerodynamically-shaped vanes in the turbine housing at the turbine inlet. In general, for light-duty engines (passenger cars, race cars, and light commercial vehicles), the vanes rotate in unison to vary the gas swirl angle and the cross sectional area. In general, for heavy-duty engines, the vanes do not rotate, but instead the axial width of the inlet is selectively blocked by an axially sliding wall (either the vanes are selectively covered by a moving slotted shroud or the vanes selectively move vs a stationary slotted shroud). Either way, the area between the tips of the vanes changes, leading to a variable aspect ratio.