Variable geometry turbine

• Main Authors: GARRETT STEPHEN EDWARD, PARKER JOHN FREDERICK
• Format: Patent
• Language: English
• Published: 23.10.2012
• Subjects: BLASTING; COMBUSTION ENGINES; CONTROLLING COMBUSTION ENGINES; ENGINE PLANTS IN GENERAL; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MACHINES OR ENGINES FOR LIQUIDS; MACHINES OR ENGINES IN GENERAL; MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENTTYPE, e.g. STEAM ENGINES; MECHANICAL ENGINEERING; NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAMTURBINES; NON-POSITIVE DISPLACEMENT PUMPS; OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR; POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PRODUCING MECHANICAL POWER; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS; STEAM ENGINES; WEAPONS; WIND MOTORS; WIND, SPRING WEIGHT AND MISCELLANEOUS MOTORS

A variable geometry turbine has a gas inlet chamber and a gas flow inlet passage downstream of the inlet chamber and upstream of said turbine wheel. The inlet passage is defined between a moveable first wall and a second wall and an actuator is operable to control displacement of the first wall in order to vary the size of the gas flow inlet passage. A piston member defining the first wall or being connected to it is received in a piston chamber and serves to move the first wall as a result of displacement of the piston member in the piston chamber. A bypass passage defined in the housing and extends between the piston chamber and a location in the turbine upstream of the inlet passage for delivering gas to the piston chamber. The bypass passage is disposed such that gas introduced through the bypass passage pressurizes the chamber and applies a force to displace the piston member in a direction that causes the first wall to move towards the second wall. The gas, which may be the exhaust gas from an engine, thus serves to assist the operation of the actuator.