TURBOCHARGER ASSEMBLY

A turbocharger assembly including a turbine housing defining an exhaust inlet opening and an exhaust outlet opening and a turbine wheel housed in the turbine housing. The turbocharger assembly also includes a compressor housing defining an air inlet opening and an air outlet opening and a compressor wheel housed in the compressor housing. The turbocharger assembly also includes a shaft coupling the turbine wheel to the compressor wheel. The turbine housing, the turbine wheel, the compressor housing, and/or the compressor wheel includes a surface having a series of protrusions or depressions configured to increase the efficiency of the turbocharger assembly.

DETAILED DESCRIPTION

The present disclosure is directed to various embodiments of a turbocharger assembly configured to increase airflow to an intake manifold of an internal combustion engine and thereby increase the output power of the engine. In one or more embodiments, one or more components of the turbocharger assembly may include a thermal barrier coating configured to reduce heat transfer between the coated component and the airflow through the turbocharger assembly. In one or more embodiments, air inlets and outlets of a compressor housing and a turbine housing of the turbocharger assembly may be configured to increase the volumetric airflow through the compressor and turbine housings. Additionally, in one or more embodiments, one or more components of the turbocharger assembly may include surface texturing or patterning configured to mitigate the formation of turbulent vortices and concomitant low pressure areas that would otherwise decrease the pressure, volume, and speed of the airflow through the turbocharger assembly and into combustion chambers of the internal combustion engine. The various features of the turbocharger assembly described below are configured to increase the performance of the turbocharger assembly and the internal combustion engine onto which the turbocharger assembly is installed. The performance gains may include faster turbocharger response times, improved throttle response, increased turbocharger efficiency, reduced fuel consumption, increased power output from the engine, increased fuel mileage, and reduced exhaust emissions.

With reference now to the embodiment illustrated inFIG. 1, a turbocharger assembly100includes a turbine housing101and a turbine wheel102housed in a chamber defined by the turbine housing101. The turbine housing101is configured to be coupled to an exhaust manifold of an internal combustion engine. The turbine housing101includes an exhaust air inlet103configured to receive exhaust airflow (arrow104) from the internal combustion engine. The exhaust airflow104is configured to enter the turbine housing101through the exhaust air inlet103, rotate the turbine wheel102housed in the turbine housing101, and exit the turbine housing101through an exhaust air outlet105in the turbine housing101.

With continued reference to the embodiment illustrated inFIG. 1, the turbocharger assembly100also includes a compressor housing106and a compressor wheel107housed in a chamber defined by the compressor housing106. The compressor wheel107is coupled to the turbine wheel102by a shaft108such that the compressor wheel107is configured to rotate synchronously with the turbine wheel102. The compressor housing106includes an air inlet opening109for receiving ambient airflow (arrow110) and an air outlet opening111for directing compressed airflow (arrow112) to an intake manifold and a series of combustion chambers of the internal combustion engine. The ambient airflow110entering the compressor housing106through the air inlet opening109is accelerated by the rotating compressor wheel107and exits the air outlet opening111as compressed airflow112having an elevated pressure (i.e., the compressed airflow112exiting the compressor housing106has a higher pressure than the ambient airflow110entering the compressor housing106). The elevated pressure of the compressed airflow112exiting through the air outlet opening111and entering the intake manifold permits a greater amount of fuel to be injected into the combustion chambers, which increases the power output of the engine.

With reference now to the embodiment illustrated inFIGS. 2 and 3A, an inner surface113of the air inlet opening109includes a plurality of depressions114(e.g., dimples). When the ambient airflow110passes over the dimples114in the air inlet opening109, the dimples114induce the formation of a turbulent boundary layer covering the inner surface113of the air inlet opening109(i.e., the dimples act as “turbulators”). The turbulent boundary layer is energized and tends to prevent or delay boundary layer airflow separation from the inner surface113of the inlet opening109. Without the presence of the dimples114, the boundary layer would tend to separate from the inner surface113of the inlet opening109, resulting in the formation of low pressure vortices that reduce the velocity, pressure, and volume of the airflow110into the compressor housing106through the air inlet opening109(i.e., the dimples114create an energized turbulent boundary layer that tends to delay the onset of airflow separation and the formation of low pressure eddies in the airflow110). Accordingly, the dimples114are configured to increase the velocity, pressure, and volume of the airflow110through the air inlet opening109of the compressor housing106, which results in the increased velocity, pressure, and volume of the compressed airflow112out from the air outlet opening111of the compressor housing106and into the combustion chambers of the internal combustion engine. In one or more alternate embodiments, the inner surface113of the air inlet opening109may include a plurality of protrusions configured to induce the formation of an energized turbulent boundary layer. In further embodiments, the inner surface113of the air inlet opening109may include a combination of a plurality of depressions and a plurality of protrusions.

Additionally, in the embodiment illustrated inFIGS. 2 and 3B, an inner surface115of the air outlet opening111includes a plurality of depressions116(e.g., dimples). In substantially the same manner described above, the dimples116in the air outlet opening111are configured to create an energized turbulent boundary layer that tends to prevent or delay boundary layer airflow separation from the inner surface115of the air outlet opening111and the concomitant formation of low pressure vortices that would reduce the velocity, pressure, and volume of the compressed airflow112out from the air outlet opening111of the compressor housing106. In one or more alternate embodiments, the inner surface115of the air outlet opening111may include a plurality of protrusions or a combination of a plurality of depressions and a plurality of protrusions.

The depressions and/or protrusions114,116in the air inlet and outlet openings109,111, respectively, of the compressor housing106may have any desired shape, such as, for instance, spherical, prismatic (e.g., square or diamond prismatic), pyramidal, conical, or any portions or combinations of such shapes. Additionally, the depressions and/or protrusions114,116may have any desired size. For instance, in one embodiment, the depressions and/or protrusions114,116may have a width or diameter from approximately 1.5 mm to approximately 9.5 mm. In another embodiment, the width or diameter of the depressions and/or protrusions114,116may range from approximately 2.5 mm to approximately 6.5 mm. The depressions and/or protrusions114,116may also have any desired depth or height. In one embodiment, the depth or height of the depressions and/or protrusions114,116may range from approximately 0.5 mm to approximately 6.5 mm. In another embodiment, the depth or height of the depressions and/or protrusions114,116may range from approximately 2.5 mm to approximately 4.0 mm. Although in one embodiment each of the protrusions or depressions114,116may have the same size and shape (e.g., the protrusions or depressions114,116may be uniform), in one or more alternate embodiments, the size and/or shape of the protrusions and/or depressions114,116may differ or vary across the inner surfaces113,115of the inlet and outlet openings109,111, respectively.

With continued reference to the embodiment illustrated inFIGS. 2 and 3A, the air inlet opening109of the compressor housing106tapers between a wider outer end121and a narrower inner end122. In one embodiment, the inlet opening109includes a chamfer or a fillet123extending between the wider and narrower ends121,122. The tapered air inlet opening109is configured to increase the maximum potential volume of ambient airflow110through the compressor housing106and thereby increase the efficiency of the turbocharger assembly100. The air inlet opening109may taper at any suitable angle α relative to an imaginary axis124of the air inlet opening109, such as, for instance, from approximately 15 degrees to approximately 60 degrees. In the embodiment illustrated inFIG. 3B, the compressor housing106may include a tapered air outlet opening111that is the same or similar to the tapered air inlet opening109. In an alternate embodiment, the tapered air outlet opening111of the compressor housing106may have a different configuration (e.g., a different taper angle) than the tapered air inlet opening109. The air outlet opening111may taper at any suitable angle β relative to an imaginary axis125of the air outlet opening111, such as, for instance, from approximately 15 degrees to approximately 60 degrees. The tapered air outlet111is configured to decrease the back pressure at the air outlet111and thereby increase the speed, volume, and pressure of the airflow110,112through the compressor housing106(e.g., the tapered air outlet111acts as a diffuser increasing the velocity of the airflow110,112through the compressor housing106). Accordingly, the tapered air outlet opening111is configured to increase the efficiency of the turbocharger assembly100by increasing the speed, volume, and pressure of the airflow112to the intake manifold of the internal combustion engine.

Still referring to the embodiment illustrated inFIGS. 2 and 3A, the compressor housing106includes a plurality of grooves or slots130circumferentially disposed around the inner surface113of the air inlet opening109. The grooves130are configured to increase the volume of airflow110through the compressor housing106by increasing the effective cross-sectional area of the inlet opening109. The grooves130may have any suitable cross-sectional shape, such as, for instance, square, rectangular, triangular (e.g., V-shaped), or semi-circular (e.g., U-shaped). Additionally, the air inlet opening109of the compressor housing106may have any suitable number of grooves130, such as, for instance, from four to twenty grooves. The grooves130may have any suitable depth, such as, for instance, from approximately 2.5 mm to approximately 7.5 mm. In one embodiment, the spacing between adjacent grooves130(i.e., the pitch of the grooves130) may range from approximately 2.5 mm to approximately 12 mm. In the illustrated embodiment, the depressions and/or protrusions114are not provided along the grooves130, although in one or more alternate embodiments, one or more depressions and/or protrusions114may be provided along the grooves130. Additionally, in the illustrated embodiment, the grooves130extend axially along the air inlet opening109(i.e., the grooves130are parallel with the axis124of the air inlet opening109).

In one or more alternate embodiments, the grooves130may be helically disposed around the inner surface113of the air inlet opening109rather than axially disposed along the air inlet opening109. The helical grooves130are configured to create a vortex of airflow to accelerate the airflow110into the compressor housing106and thereby draw increased airflow110through the compressor housing106and into the combustion chambers of the engine. The helical grooves130may be oriented at any suitable angle, such as, for instance, from approximately 15 degrees to approximately 50 degrees relative to the axis124of the inlet opening109. In general, helical grooves oriented at larger angles are configured to produce increased turbocharger efficiency at lower internal combustion engine speeds and helical grooves oriented at relatively smaller angles are configured to produce increased turbocharger efficiency at higher internal combustion engine speeds. Accordingly, the angle of the helical grooves may be selected based upon the intended operating conditions of the internal combustion engine and the desired performance characteristics of the turbocharger assembly100.

Additionally, in the embodiment illustrated inFIG. 3B, the inner surface115of the air outlet opening111of the compressor housing106may include a plurality of grooves131that are the same or similar to the grooves130in the air inlet opening109. In an alternate embodiment, the grooves131in the outlet opening111may have a different configuration (e.g., a different angle and/or cross-sectional shape) than the grooves130in the air inlet opening109. The grooves131may be axially or helically disposed around the inner surface115of the air outlet opening111. The grooves131in the air outlet opening111are configured to increase the volume of compressed airflow112out from the compressor housing106and into the intake manifold of the internal combustion engine by increasing the cross-sectional area of the air outlet opening111. Accordingly, the grooves130,131in the air inlet109and/or air outlet111, respectively, of the compressor housing106are configured to increase the efficiency of the turbocharger assembly100and the power output of the internal combustion engine.

With reference now to the embodiment illustrated inFIGS. 4,5A, and5B, inner surfaces117,118of the exhaust air inlet103and exhaust air outlet105, respectively, of the exhaust turbine housing101may include a plurality of protrusions and/or depressions (e.g., dimples)119,120, respectively. The protrusions and/or depressions119,120may have any suitable shape, such as, for instance, spherical, prismatic (e.g., square or diamond prismatic), pyramidal, conical, or any portions or combinations of such shapes, and any desired size, such as, for instance, a width or diameter from approximately 1.5 mm to approximately 9.5 mm and a depth or height from approximately 0.5 mm to approximately 6.5 mm. The protrusions and/or depressions119,120in the exhaust air inlet103and the exhaust air outlet105, respectively, may be the same or similar to the protrusions and/or depressions114,116in the air inlet opening109and the air outlet opening111, respectively, of the compressor housing106. In an alternate embodiment, the protrusions and/or depressions119,120in the exhaust air inlet103and/or exhaust air outlet105of the exhaust turbine housing101may have a different configuration (e.g., a different size or shape) than the protrusions and/or depressions114,116in the air inlet opening109and air outlet opening111, respectively, of the compressor housing106.

With continued reference to the embodiment illustrated inFIGS. 4 and 5A, the exhaust inlet opening103of the exhaust turbine housing101may taper between a wider outer end126and a narrower inner end127to increase the maximum potential exhaust airflow104through the turbine housing101and thereby increase the efficiency of the turbocharger assembly100. As illustrated inFIG. 5B, the exhaust outlet105of the exhaust turbine housing101may similarly taper between a wider outer end128and a narrower inner end129to reduce the back pressure at the exhaust outlet105and thereby increase the velocity of the exhaust airflow104through the exhaust turbine housing101(e.g., the tapered exhaust outlet105acts as a diffuser increasing the velocity of the exhaust airflow104through the exhaust turbine housing101). The exhaust inlet103and the exhaust outlet105may taper at any suitable angles, such as, for instance, from approximately 15 degrees to approximately 60 degrees. Although in one embodiment the configuration of the exhaust inlet103may be the same or similar to the configuration of the exhaust outlet105, in one or more alternate embodiments, the configuration of the exhaust inlet103may differ from the configuration of the exhaust outlet105(e.g., the exhaust inlet103may taper at a different angle than the exhaust outlet105).

Still referring to the embodiment illustrated inFIGS. 4,5A, and5B, the inner surfaces117,118of the exhaust inlet103and the exhaust outlet105, respectively, of the exhaust turbine housing101may include a plurality of grooves132,133, respectively. The grooves132,133may be axially or helically disposed around the inner surfaces117,118of the exhaust inlet103and the exhaust outlet105, respectively. The grooves132,133may have any suitable cross-sectional shape, such as, for instance, square, rectangular, triangular (e.g., V-shaped), or semi-circular (e.g., U-shaped), and any suitable depth, such as, for instance, from approximately 2.5 mm to approximately 7.5 mm. The exhaust inlet103and the exhaust outlet105of the exhaust turbine housing101may each have any suitable number of grooves132,133, such as, for instance, from four to twenty grooves. Additionally, in one embodiment, the spacing between adjacent grooves132,133, respectively, may range from approximately 2.5 mm to approximately 12 mm. In one embodiment, the grooves132,133in the exhaust inlet103and the exhaust outlet105may be the same or similar to the grooves130,131in the air inlet109and the air outlet111of the compressor housing106. In an alternate embodiment, the grooves132,133in the exhaust inlet103and/or the exhaust outlet105may have a different configuration (e.g., a different shape, size, or pitch) than the grooves130,131in the air inlet109and/or air outlet111of the compressor housing106. Additionally, in one embodiment, the grooves132in the exhaust inlet103may have a different configuration than the grooves133in the exhaust outlet105.

With reference again to the embodiment illustrated inFIGS. 2,3A, and3B, outer surfaces134and/or inner surfaces135of the compressor housing106may be coated with a thermal barrier coating. The thermal barrier coatings are configured to prevent heat transfer between the exhaust turbine housing101and the compressor housing106. Reducing heat transfer between the exhaust turbine housing101and the compressor housing106aids in maintaining a lower temperature of the intake airflow110flowing through the compressor housing106. The lower intake airflow temperature increases the density of the intake airflow110, which results in increased efficiency of the turbocharger assembly100and increased power output from the internal combustion engine.

Similarly, in the embodiment illustrated inFIGS. 4,5A, and5B, thermal barrier coatings may be applied to outer and/or inner surfaces136,137, respectively, of the exhaust turbine housing101to aid in reducing heat transfer to the compressor housing106and the intake airflow110flowing through the compressor housing106. The thermal barrier coatings on the exhaust turbine housing101are configured to contain the heat from the exhaust airflow104within the exhaust turbine housing101. To further reduce heat transfer between the exhaust turbine housing101and the compressor housing106, a central bearing housing, which supports the shaft108and extends between the exhaust turbine housing101and the compressor housing106, may be coated with a thermal barrier coating. The thermal barrier coatings may be made out of any suitable material, such as, for instance, an aluminum-filled ceramic coating. In one embodiment, the thermal barrier coatings on the central bearing housing and the outer surfaces136of the turbine housing101may be CBX or CBC-2, offered by Tech Line Coatings, Inc., or equivalents thereof. In one embodiment, the thermal barrier coating on the inner surfaces137of the turbine housing101may be Tech Line's TLHB Hi Heat Coating or equivalents thereof.

With reference now to the embodiment illustrated inFIG. 6, the compressor wheel107includes a base138and a cylindrical hub139projecting outward from the base138. The hub139is configured to receive one end140of the shaft108(seeFIG. 1) coupling the compressor wheel107to the turbine wheel102. The compressor wheel107also includes a nut141for securing the compressor wheel107to the end140of the shaft108. The compressor wheel107further includes a plurality of blades or vanes142radially disposed around the hub139and the base138. Although the compressor wheel107in the illustrated embodiment includes eight blades142, in one or more alternate embodiments, the compressor wheel107may include any other suitable number of blades142, such as, for instance, from four to twenty blades. In the illustrated embodiment, each blade142includes a curved leading edge143and a trailing edge144coupled to the base138. Each of the blades142also includes a contoured outer edge145such that the leading edge143of each blade142is narrower than the trailing edge144. Each blade142also includes a front surface146and a rear surface147.

With continued reference to the embodiment illustrated inFIG. 6, each blade142of the compressor wheel107also includes a plurality of depressions (e.g., dimples) and/or protrusions148. In the illustrated embodiment, the depressions and/or protrusions148are located on the rear surfaces147of the blades142proximate to the leading edges143. In one or more alternate embodiments, the depressions and/or protrusions148may be provided along the entire rear surfaces147of the blades142or at any other suitable locations, such as, for instance, on the front surfaces146of the blades142or on an outer surface149of the base138. The depressions and/or protrusions148are configured to induce energized turbulent boundary layers that tend to prevent or delay airflow separation from the surfaces146,147of the blades142and the concomitant formation of low-pressure vortices. Accordingly, the depressions and/or protrusions148are configured to reduce the aerodynamic drag on the blades142of the compressor wheel107. The reduced drag on the blades142increases the rotational speed of the compressor wheel107, which increases the volume of airflow110through the compressor housing106and into the intake manifold of the internal combustion engine. The depressions and/or protrusions148on the blades142of the compressor wheel107may have any desired shape, such as, for instance, spherical, prismatic (e.g., square or diamond prismatic), pyramidal, conical, or any portions or combinations of such shapes. Additionally, the depressions and/or protrusions148may have any desired size, such as, for instance, a width or diameter from approximately 1.5 mm to approximately 9.5 mm and a depth or height from approximately 0.5 mm to approximately 6.5 mm.

With reference now to the embodiment illustrated inFIG. 7, the exhaust turbine wheel102includes a base150, a cylindrical hub151projecting outward from the base150, and a plurality of blades or vanes152radially disposed around the hub151and the base150. The cylindrical hub151is configured to receive an end153of the shaft108(seeFIG. 1) coupling the turbine wheel102to the compressor wheel107. The turbocharger assembly100also includes a nut154for securing the turbine wheel102to the end153of the shaft108. In one embodiment, the exhaust turbine wheel102may have the same or substantially similar configuration as the compressor wheel107. In one or more alternate embodiments, the configuration of the turbine wheel102may differ from the configuration of the compressor wheel107. For instance, in one embodiment, the number of blades152on the turbine wheel102may differ from the number of blades142on the compressor wheel107. Additionally, in one embodiment, the shape of the blades152on the turbine wheel102may differ from the shape of the blades142on the compressor wheel107, In the illustrated embodiment, the turbine wheel102includes a plurality of depressions and/or protrusions155on front and rear surfaces156,157, respectively, of the blades152and on an outer surface158of the base150. In one or more alternate embodiments, the depressions and/or protrusions155may be provided at any other suitable locations on the turbine wheel102, such as, for instance, on only the blades152or portions thereof. The depressions and/or protrusions155are configured to induce turbulent boundary layers that eliminate or reduce the formation of low pressure vortices and thereby reduce the aerodynamic drag on the blades152of the turbine wheel102. The reduced drag on the blades152increases the rotational speed of the turbine wheel102, which in turn increases the rotational speed of the compressor wheel107and the volume and speed of airflow110through the compressor housing106and into the intake manifold of the internal combustion engine.

With continued reference to the embodiment illustrated inFIGS. 6 and 7, outer edges159,160of the blades142,152on the compressor wheel107and the exhaust turbine wheel102, respectively, are rounded or filleted. Additionally, in the illustrated embodiments, circumferential outer edges161,162of the bases138,150of the compressor wheel107and the exhaust turbine wheel102are rounded or filleted. The rounded edges159,160,161,162are configured to reduce the aerodynamic drag induced on the exhaust turbine wheel102and the compressor wheel107by the exhaust airflow103and the ambient airflow110through the turbine housing101and the compressor housing106, respectively (i.e., the elimination of sharp edges reduces the drag on the exhaust turbine wheel102and the compressor wheel107). The reduced drag on the exhaust turbine wheel102and the compressor wheel107allows the exhaust turbine wheel102and the compressor wheel107to spin faster, which increases the flow rate of the compressed airflow112out of the air outlet111of the compressor housing106and into the combustion chambers of the engine. Accordingly, eliminating the sharp edges on the turbine wheel102and the compressor wheel107increases the efficiency of the turbocharger assembly100and the power output of the internal combustion engine. In one or more alternate embodiments, the exhaust turbine wheel102and the compressor wheel107may have any other features for breaking the sharp edges of the blades142,152and the bases138,150, such as, for instance, chamfers.

With continued reference to the embodiment illustrated inFIGS. 6 and 7, the compressor wheel107and the turbine wheel102may each be coated with a thermal barrier coating. The thermal barrier coating is configured to reduce heat transfer from the exhaust turbine housing101and the turbine wheel102to the compressor housing106, the compressor wheel107, and the intake air110flowing through the compressor housing106. As described above, reducing heat transfer to the compressor housing106increases the density of the intake air110and thereby increases the efficiency of the turbocharger assembly100. The thermal barrier coatings may be applied to any desired surfaces of the compressor wheel107and the turbine wheel102, such as, for instance, the blades142,152, the bases138,150, the hubs139,151, and/or portions thereof. The thermal barrier coatings may be made out of any suitable material, such as, for instance, an aluminum-filled ceramic coating (e.g., Tech Line's CBX, CBX-2, or TLHB Hi Heating Coating) or equivalents thereof.

The compressor housing106, compressor wheel107, exhaust turbine housing101, and the turbine wheel102may be formed by any suitable process, such as, for instance, casting, machining (e.g., milling), additive manufacturing, or combinations thereof. Additionally, the compressor housing106, compressor wheel107, exhaust turbine housing101, and the turbine wheel102may be made out of any suitable material, such as, for instance, metal (e.g., aluminum or steel), metal alloy, composite (e.g., carbon fiber reinforced plastic), or combinations thereof.

While this invention has been described in detail with particular references to exemplary embodiments thereof, the exemplary embodiments described herein are not intended to be exhaustive or to limit the scope of the invention to the exact forms disclosed. Persons skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structures and methods of assembly and operation can be practiced without meaningfully departing from the principles, spirit, and scope of this invention, as set forth in the following claims. Although relative terms such as “outer,” “inner,” “upper,” “lower,” “below,” “above,” and similar terms have been used herein to describe a spatial relationship of one element to another, it is understood that these terms are intended to encompass different orientations of the various elements and components of the invention in addition to the orientation depicted in the figures. Additionally, as used herein, the term “substantially” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. Furthermore, as used herein, when a component is referred to as being “on” another component, it can be directly on the other component or components may also be present therebetween. Moreover, when a component is component is referred to as being “coupled” to another component, it can be directly attached to the other component or intervening components may be present therebetween. Moreover, although the embodiments described above are directed to turbocharger modifications, one or more of the modifications to the compressor of the turbocharger (e.g., protrusions and/or depressions, thermal barrier coatings, tapered air inlets and/or outlets, and grooves) may also be applied to a supercharger or other types of air pressure boosters for internal combustion engines. Additionally, the turbochargers of the present disclosure may be applied to any suitable type of internal combustion engines, such as, for instance, two- or four-cycle spark ignition engines or two- or four-cycle compression ignition engines.