Claims:1. An improved efficiency turbocharger assembly with streamlined inlet flow, comprising of : a rotating shaft (122), having a first end (133) and a second end (134); atleast a compressor wheel (123) having a plurality of blades, wherein said compressor wheel is disposed at said first end (133) of the rotating shaft, the said compressor wheel is positioned within the compressor housing (124); atleast a turbine (125) connected in tandem with the said compressor wheel (123), disposed at said second end (134) of the rotating shaft (122), wherein said turbine (125) is accommodated within the turbine housing (126); and an aerodynamic fastening means (127) having a first end and second end, wherein said second end (135) of the aerodynamic fastening means is provided with a provision for accommodating the said first end of the rotating shaft, wherein said fastening means secures the said compressor wheel (123) on to the said first end (133) of the rotating shaft.

2. An improved efficiency turbocharger assembly, as claimed in claim 1, wherein said aerodynamic fastening means (127) is hemi-spherical, conical, dome, bullet, frusto-spherical or frusto-conical in shape.

3. An improved efficiency turbocharger assembly, as claimed in claim 1 and 2, wherein said aerodynamic fastening means (127) is provided with a recess at its first end.

4. An improved efficiency turbocharger assembly, as claimed in claim 1 and 2, wherein said aerodynamic fastening means (127) is integrated with a hexagonal nut at its first end.

5. An improved efficiency turbocharger assembly, as claimed in claim 1 and 2, wherein said aerodynamic fastening means (127) is integrated with a hexagonal nut at its second end.

6. An improved efficiency turbocharger assembly, as claimed in claim 1 and 2, wherein said aerodynamic fastening means (127) is provided with a plurality of provisions (132a, 132b, 132c, 132d, 132e, 132f, 132g,132h) for holding and tautening the said aerodynamic fastening means (127) in position with the said first end (133) of the rotating shaft (122).

7. An improved efficiency turbocharger assembly, as claimed in any of the preceding claims, provides a smooth hub at the inlet port of the compressor wheel (123), eliminating the flow disturbances at the inlet port and improving the overall efficiency and performance of the turbocharger assembly.

, Description:AERODYNAMIC FASTENERS FOR IMPROVED EFFICIENCY TURBOCHARGER
FIELD OF THE INVENTION
The present invention relates to turbochargers, more particularly, it relates to turbochargers with aerodynamic fastening means which improves the overall efficiency and performance of the turbochargers.
BACKGROUND OF THE INVENTION
Turbocharger is a turbine driven forced induction device used in combination with internal combustion engine for increasing the power output of the engine. Turbocharger delivers compressed air to the intake of the internal combustion engine to be mixed with fuel and burned in the engine allowing more fuel to be combusted, thus boosting the power output of the engine without increasing the engine weight. The turbochargers apart from improving the fuel efficiency also reduces the emission and improves the driveability of the engine. Major use of turbochargers includes passenger car, commercial vehicles, train, aircraft, construction equipment engines, industrial and marine applications. To meet the global emission norms and performance expectations, various designs of turbochargers have been introduced in the market by the global Turbo manufacturers.
Typical turbochargers consist of a centrifugal compressor and a radial turbine connected in tandem onto the rotating turbine shaft. The overall efficiency of turbocharger depends on the performance of compressor and the turbine, whereas the efficiency of the compressor depends on its geometry. The compressor wheels are secured to the turbine shaft by means of a securing nut, which is normally a standard hexagonal nut and does not provide optimum aerodynamic performance of the compressor wheels. Compressor wheel has flow entering the wheel (blades) axially in the frame of reference fixed to the compressor housing (or Stationary). Uniform flow at the entry of compressor is crucial for the overall efficiency of the turbocharger. Due to manufacturing and assembly process typical compressor wheel has a nearly sharp step at the entrance. It is observed that the presence of step reduces the efficiency due to flow disturbance at the inlet/entry port. Compressor wheel with a step has lower efficiency compared to the one that has a smoother entry (hub). In reality the sharpness will be little less pronounced due to the presence of hexagonal nut, nevertheless it exists. The present invention improves the overall efficiency and performance of turbochargers by reducing the flow disturbance and non-uniformity of the inlet flow entering the compressor wheel by providing a smooth, streamlined and aerodynamic fastening means for securing the compressor wheel onto the turbocharger shaft.
WO2013104880 discloses a turbocharger having a connector for connecting an impeller to a shaft. The impeller has a shaft-side hub extension with a central recess. The impeller is formed of a material having a greater coefficient of thermal expansion than the material of the shaft. The connector is inserted into the recess to frictionally connect an outwardly facing surface of the connector with a radially inner surface of the hub extension. The connector has a threaded portion carrying a thread which screws onto a corresponding threaded portion of the shaft, such that the connector provides a rotationally fixed connection between the impeller and the shaft. The connector is formed of a material having a coefficient of thermal expansion which is greater than the coefficient of thermal expansion of the shaft material.
WO2010089028 relates to an exhaust gas turbocharger having an impeller disposed on a rotatable shaft, said impeller being secured in the axial direction by means of a threaded element, wherein the threaded element comprising a thread comprises a drive segment for interacting with a drive tool for tightening or releasing the threaded element. The drive segment is formed as an external cone segment.
US6481970 provides a compressor wheel for a turbocharger having a pre-stressed hub with an interference fit insert sized to provide the predetermined stress at zero rotational speed. The compression wheel assembly comprises of a separate nose insert which incorporates the nut and is threaded on to the shaft. This streamlined nose design reduces flow distortions at the nose and thus improves aerodynamic performance of the compressor wheel.
US8944771 reports a method for reducing the core unbalance of turbochargers by using a centering device. A special frusto-conical, or frusto-spherical, centering geometry is added to the interface of the compressor nut and the nose of the compressor wheel to aid in keeping the wheel, nut, and stub-shaft centered on the turbocharger axis to reduce the degree of core unbalance.
IN1581/KOL/2007 provides a rotor for a turbo compressor capable of increasing the amount of elongation of a tension bolt for fastening an impeller and a rotary shaft of the turbo compressor, thereby improving the efficiency of coupling operation, and achieving stabilization. The rotor includes a fastening mechanism having a mechanical joint formed at an end face of each of the impeller and the rotary shaft, a tension bolt inserted through a through-hole fanned in the center of rotation of the impeller, a fastening nut screwed to a first male thread formed at one end of the tension bolt, a housing hole formed at an end face of the rotary shaft to house a portion of an elongated portion of the tension bolt, and a female thread formed at a bottom face of the housing hole and screwed to a second male thread formed at the other end of the tension bolt.
CN20131744821 discloses a compressor impeller of the small-sized turbo-supercharger comprises a shaft seal, a pressing wheel and a nut; the pressing wheel comprises a wheel disc and blades; the oil seal, the pressing wheel and the nut are integrally arranged; the end portion of the nut is arranged to be in a bullet shape; the peripheral surface of the shaft seal is provided with at least two piston grooves. The compressor impeller of the small-sized turbo-supercharger has the advantages of reducing the number of parts, reducing costs, being benefited to wide utilization in small-displacement family cars; reducing machining accuracy and indirectly reducing machining costs due to the fact that the shaft seal and the pressing wheel are integrally formed.
Most of the above cited prior-art documents deals with the securing and releasing means for the compressor wheels onto the turbine shaft, material strength of the securing means, stability and balancing of the turbochargers during high rotational speeds etc. None of the above said turbochargers and their compressor wheels deals with the effect of aerodynamics on the overall performance of the turbochargers. Therefore, there exists a need in the art for addressing the problems associated with aerodynamics of the compressor wheel which has a major effect in overall performance and efficiency of the turbochargers. The present invention attempts to address the said issue by providing an aerodynamic fastening means for securing the compressor wheel onto the turbocharger shaft, thereby streamlining the inlet flow and eliminating the flow disturbance at the entry port thus improving the overall performance and efficiency of the turbocharger.
OBJECTIVE OF THE INVENTION
The main objective of the present invention is to provide a turbocharger assembly with improved overall performance and efficiency.
Another objective of the present invention is to provide a turbocharger assembly with an aerodynamic fastening means for securing the compressor wheel onto the turbocharger shaft.
Yet another objective of the present invention is to eliminate the flow disturbance and streamline the flow at the compressor wheel entry port, thereby increasing the overall performance and efficiency of the turbocharger.
Additional objective of the present invention is to provide an aerodynamic fastener with provisions for easy and efficient fastening of the compressor wheel onto the turbocharger shaft.
BRIEF DESCRIPTION OF DRAWING:
Figure 1 depicts the state of the art turbocharger assembly.
Figure 2 illustrates the turbocharger assembly of the present invention with aerodynamic fastening means.
Figure 3 shows the flow disturbance at the inlet of the compressor wheel with a step hub (which approximately describes the flow entering into a compressor wheel with a standard hexagonal nut).
Figure 4 shows the streamlined flow at the inlet of the compressor wheel with a smooth hub.
Figure 5 illustrates an embodiment of the present invention the aerodynamic fastening means with Allen key configuration.
Figure 6a & 6b demonstrates an embodiment of the present invention the aerodynamic fastening means integrated with a hexagonal nut at its first end.
Figure 7a & 7b exemplifies the aerodynamic fastening means according to an embodiment of the present invention.
Figure 8 represents an embodiment of the present invention the aerodynamic fastening means integrated with a hexagonal nut at its second end.
While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
SUMMARY
The present invention provides an improved efficiency turbocharger assembly, comprising of: a rotating shaft (122); atleast a compressor wheel (123), disposed at first end (133) of the rotating shaft; atleast a turbine (125) connected in tandem with the said compressor wheel (123); and an aerodynamic fastening means (127) provided with a provision (135) for accommodating the said first end (133) of the rotating shaft, wherein the said aerodynamic fastening means (127) secures the said compressor wheel (123) on to the rotating shaft. The aerodynamic fastening means (127) of the present invention creates a smooth hub at the entry port of the compressor wheel thereby eliminating the flow disturbances at the entry port and streamlining the inlet flow at the compressor wheel. In an embodiment of the present invention, said aerodynamic fastening means (127) is hemi-spherical, conical, dome, bullet, frusto-spherical or frusto-conical in shape. The aerodynamic fastening means may optionally be provided with a plurality of provisions (132a, 132b, 132c, 132d, 132e, 132f, 132g,132h) for holding and tautening the said aerodynamic fastening means (127) in position with the said first end (133) of the rotating shaft (122). In an embodiment of the present invention the aerodynamic fastener (127) is provided with a recess (129) at its first end or integrated with a hexagonal nuts (130a, 130b, 131a) at its either ends. Aerodynamic fastening means (127) of the present invention eliminates the flow disturbance and streamlines the flow at the compressor wheel entry port, thereby increasing the overall performance and efficiency of the turbocharger.
DETAILED DESCRIPTION OF THE INVENTION:
The present invention as embodied by an improved efficiency turbocharger with aerodynamic fastener, succinctly fulfils the above-mentioned need(s) in the art. The present invention has objective(s) arising as a result of the above-mentioned need(s), said objective(s) being enumerated below. In as much as the objective(s) of the present invention are enumerated, it will be obvious to a person skilled in the art that, the enumerated objective(s) are not exhaustive of the present invention in its entirety, and are enclosed solely for the purpose of illustration. Further, the present invention encloses within its scope and purview, any structural alternative(s) and/or any functional equivalent(s) even though, such structural alternative(s) and/or any functional equivalent(s) are not mentioned explicitly herein or elsewhere, in the present disclosure. The present invention therefore encompasses also, any improvisation(s)/modification(s) applied to the structural alternative(s)/functional alternative(s) within its scope and purview. The present invention may be embodied in other specific form(s) without departing from the spirit or essential attributes thereof.
Throughout this specification, the use of the word "comprise" and variations such as "comprises" and "comprising" may imply the inclusion of an element or elements not specifically recited.
The present invention provides an improved efficiency turbocharger assembly, comprising of: a rotating shaft (122), having a first end (133) and a second end (134); atleast a compressor wheel (123) having a plurality of blades, disposed at said first end (133) of the rotating shaft, the said compressor wheel (123) is positioned within the compressor housing (124); atleast a turbine (125) connected in tandem with the said compressor wheel (123), disposed at said second end (134) of the rotating shaft (122), wherein said turbine (125) is accommodated within the turbine housing (126); and an aerodynamic fastening means (127) having a first end and a second end, wherein the said second end of the aerodynamic fastening means (127) is provided with a provision (135) for accommodating the said first end (133) of the rotating shaft, wherein the said fastening means secures the said compressor wheel (123) onto the said first end (133) of the rotating shaft, wherein said aerodynamic fastening means (127) eliminates the flow disturbance and streamlines the flow at the entry port.
Conventionally, standard hexagonal nuts (128) are used as a fastening means for securing the compressor wheel onto the rotating shaft, this provides a step increase on the compressor wheel and do not provide any aerodynamic effect on the compressor wheel. Further this step hub due to the standard hexagonal nut (128) creates flow disturbances and non-uniformity at the entry port as shown in fig.3, this reduces the overall performance and efficiency of the turbochargers. The aerodynamic fastening means (127) of the present invention creates a smooth hub at the entry port thereby eliminating the flow disturbances at the entry port and streamlining the inlet flow.
In an embodiment of the present invention, wherein the said aerodynamic fastening means (127) is hemi-spherical, conical, dome, bullet, frusto-spherical or frusto-conical in shape.
In an embodiment of the present invention, wherein said aerodynamic fastening means (127) is provided with a recess (129) at its first end, wherein the said recess (129) functions as a means for holding and tautening the said aerodynamic fastening means (127) in position with the said first end (133) of the rotating shaft (122).
In an embodiment of the present invention, wherein said aerodynamic fastening means (127) is integrated with a hexagonal nut (130a & 130b) at its first end, wherein the said hexagonal nut (130a & 130b) functions as a means for holding and tautening the said aerodynamic fastening means (127) in position with the said first end (133) of the rotating shaft (122).
In an embodiment of the present invention, wherein the said aerodynamic fastening means (127) is integrated with a hexagonal nut (131a) at its second end, wherein the said hexagonal nut (131a & 131b) functions as a means for holding and tautening the said aerodynamic fastening means (127) in position with the said first end (133) of the rotating shaft (122).
In an embodiment of the present invention, wherein said aerodynamic fastening means of the present invention is further provided with a plurality of provisions (132a, 132b, 132c, 132d, 132e, 132f, 132g,132h) for holding and tautening the said aerodynamic fastening means (127) in position with the said first end (133) of the rotating shaft (122).
Efficiency of the turbocharger performance is directly related to the performance of the compressor wheel (123). The aerodynamic fastening means (127) of the present invention creates a smooth hub at the centre of the compressor wheel (123) providing a uniform or streamlined inlet flow improving the performance of the compressor wheel, thereby increasing the overall efficiency and performance of the turbocharger.
It will be apparent to a person skilled in the art that the above description is for illustrative purposes only and should not be considered as limiting. Various modifications, additions, alterations, and improvements without deviating from the spirit and the scope of the invention may be made by a person skilled in the art.