RETRACTABLE HOLLOW NOZZLE VANE
Publication Date: 2016-Nov-16
The IP.com Prior Art Database
A technique to vary the gas flow path area using a retractable hollow vane in a variable geometry turbocharger (VGT) is disclosed. The technique enables efficient operation of the VGT during multiple turbine running conditions. During normal turbine working conditions, for example, when maximum flow area is required, retractable hollow vane is not pushed in to a flow path resulting in more area between nozzle vanes. When flow area is required to be reduced, retractable hollow vane is pushed, such that, the retractable hollow vanes envelopes the fixed vane. Subsequently, the flow takes an outer shape of the retractable hollow vane, thereby, resulting in change in flow area. As a result, the turbine is able to operate at same speed during lower notch conditions. According to an embodiment, retractable hollow vanes can be combined with retractable blades that sit between the existing vanes, thereby, enabling an additional benefit of operating in another extra turbine engine running condition
The present invention relates generally to a variable geometry turbine used in turbochargers, and more particularly to a technique for varying a gas flow path area in the nozzle of the variable geometry turbines.
Generally, variable geometry turbocharger (VGT) uses variable vanes to control exhaust flow against turbine blades. The vane angles are adjusted via an actuator. The angle of the vanes varies throughout the working of an engine to optimize turbine behavior. However, life of the vanes is considerably affected during different operating conditions of the engine. This is due to continuous exposure of vanes to harsh conditions during maximum or reduced fluid flow area requirement.
A conventional technique includes a variable geometry turbine comprising a turbine wheel mounted for rotation about a turbine axis within housing. The housing defines an annular inlet that surrounds the turbine wheel and defined between first and second inlet sidewalls. The annular inlet is divided into plurality of axially offset inlet portions. A cylindrical sleeve is axially movable across an annular inlet to vary size of a gas flow path through the inlet, wherein an axial extent of a leading end of the sleeve varies in magnitude around a circumference of the sleeve. However, the above mentioned conventional technique does not enable efficient operation of the variable geometry turbine during multiple turbine running conditions.
Therefore, it would be desirable to have a technique to vary a gas flow path area in the nozzle of the variable geometry turbines to enable efficient operation of the engine during multiple turbine running conditions.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 depicts a nozzle ring assembly including only fixed vanes, wherein retractable hollow vanes are not pushed into the flow path.
Figure 2 depicts the nozzle ring assembly including a set of retractable hollow vanes enveloped around the fixed vanes.
Figure 3 depicts the retractable hollow vane designed such that it varies the flow area between the airfoils 1-2 and 1-3.
Figure 4a depicts the change in flow area with one set of retractable hollow vane design – odd numbered vanes.
Figure 4b depicts the change in the flow area with other set of retractable hollow vane design – even numbered vanes.
Figure 5 depicts nozzle ring assembly including fixed vanes and a groove in which retractable hollow vane resides.
Figure 6 depicts nozzle ring with or individual retractable hollow vanes.
A technique to vary the gas flow path area using a retractable hollow vane in a variable geometry turbocharger (VGT) is disclosed. The technique enables efficient operation of the VGT during multiple turbine running conditions. During normal turbine working conditions, for example, when maximum flow area is required, retractable hollow vane is not pushed in to a flow path resulting in more area between nozzle vanes. Figure 1 depicts a nozzle ri...