Turbocharger having a variable inlet area turbine

Abstract

A turbocharger for a diesel engine 34, wherein combustion air is supplied under pressure to the engine's intake manifold 32 from a centrifugal compressor 20 rotated by a turbine wheel 18 driven by exhaust gas from the engine supplied to inlet volute 44. Exhaust gas from the volute impinges on the turbine wheel after passing between stationary vanes 60 in an annular inlet passage between thin wall 52 and wall 46 of turbine housing 40. In this passage is a thin wall annular flange 64 slotted to fit over the vanes. The flange is part of a thin wall ring 62 stamped from stainless steel movable across the passage to control the inlet area thereof. The ring 62 is movable by actuators 80 (only one shown) having rods 74 connected to the ring. Springs 116 act on the rods 74 to urge the flange 64 towards the wall 46 thus reducing the area of the inlet passage so exhaust gas rushes through the reduced inlet and speeds the turbine and compressor providing at manifold 32 an increased air pressure. This increased pressure is used to urge diaphragm 100 in the actuators 80 in opposition to the springs and thus move ring 62 to increase the inlet passage area. The thinness of the ring 62 minimizes the chance that exhaust products will make it stick to vanes 46 and enables the ring to move quickly in response to actuators 80. Also the ring is cheap to make.