U.S. patent application number 12/597787 was filed with the patent office on 2010-04-29 for variable turbine geometry turbocharger.
This patent application is currently assigned to BorgWarner Inc.. Invention is credited to Paul Anschel, David G. Grabowska.
Application Number | 20100104424 12/597787 |
Document ID | / |
Family ID | 39944188 |
Filed Date | 2010-04-29 |
United States Patent
Application |
20100104424 |
Kind Code |
A1 |
Anschel; Paul ; et
al. |
April 29, 2010 |
VARIABLE TURBINE GEOMETRY TURBOCHARGER
Abstract
A turbocharger is provided having a turbine wheel (4, 4') with a
plurality of extended tips (400, 400'); and a variable turbine
geometry assembly in fluid communication with the turbine wheel and
having a nozzle ring (6) with a plurality of vanes (7) movably
attached thereto. One or more of the extended tips are non-parallel
with an edge of one or more of the plurality of vanes. The
incidence angle can vary and can be from 1 to 60 degrees. The
extended tips can extend into an inlet of the vane space housing
the vanes.
Inventors: |
Anschel; Paul; (Asheville,
NC) ; Grabowska; David G.; (Asheville, NC) |
Correspondence
Address: |
BORGWARNER INC. C/O PATENT CENTRAL LLC
1401 HOLLYWOOD BOULEVARD
HOLLYWOOD
FL
33020-5237
US
|
Assignee: |
BorgWarner Inc.
Auburn Hills
MI
|
Family ID: |
39944188 |
Appl. No.: |
12/597787 |
Filed: |
April 29, 2008 |
PCT Filed: |
April 29, 2008 |
PCT NO: |
PCT/US08/61875 |
371 Date: |
October 27, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60916175 |
May 4, 2007 |
|
|
|
Current U.S.
Class: |
415/159 |
Current CPC
Class: |
Y02T 10/144 20130101;
F05D 2220/40 20130101; F01D 5/048 20130101; F05D 2250/314 20130101;
F02B 37/24 20130101; F05D 2250/312 20130101; F01D 17/165 20130101;
Y02T 10/12 20130101 |
Class at
Publication: |
415/159 |
International
Class: |
F01D 17/12 20060101
F01D017/12 |
Claims
1. A turbocharger (1) comprising: a turbine wheel (4, 4') having a
plurality of extended tips (400, 400'); and a variable turbine
geometry assembly in fluid communication with the turbine wheel and
having a nozzle ring (6) with a plurality of vanes (7) movably
attached thereto, wherein one or more of the extended tips are
non-parallel with an edge of one or more of the plurality of
vanes.
2. The turbocharger of claim 1, wherein all of the extended tips
are non-parallel with all of the edges of the plurality of
vanes.
3. The turbocharger (1) of claim 1, wherein the extended tips are
at an angle with the edges of the plurality of vanes of between 1
and 60 degrees.
4. The turbocharger (1) of claim 1, wherein the extended tips are
at an angle with the edges of the plurality of vanes of between 5
and 45 degrees.
5. The turbocharger (1) of claim 1, wherein the extended tips are
at an angle with the edges of the plurality of vanes of between 10
and 30 degrees.
6. The turbocharger (1) of claim 1, wherein the plurality of vanes
are positioned in a vane space (13) that is in fluid communication
with the turbine wheel, wherein the vane space has an inlet (500)
and wherein the extended tips extend into the inlet.
7. A method of operating a turbocharger (1), the method comprising:
providing an exhaust gas flow to a turbine wheel (4) of a variable
turbine geometry turbocharger, wherein the exhaust gas flow is a
mixed flow having both a radial component and an axial component,
and wherein the mixed flow is formed by at least one of leakage
gas, secondary flow and a non-parallel incidence angle of the
turbine wheel.
8. The method of claim 7, comprising providing extended tips for
the turbine wheel, wherein the extended tips are at an angle with
edges of plurality of vanes of between 1 and 60 degrees.
9. The method of claim 7, comprising providing extended tips for
the turbine wheel, wherein the extended tips are at an angle with
edges of plurality of vanes of between 5 and 45 degrees.
10. The method of claim 7, comprising providing extended tips for
the turbine wheel, wherein the extended tips are at an angle with
edges of plurality of vanes of between 10 and 30 degrees.
11. The method of claim 8, wherein the plurality of vanes are
positioned in a vanes space (13) that is in fluid communication
with the turbine wheel, wherein the vane space has an inlet (500)
and wherein the extended tips extend into the inlet.
Description
FIELD OF THE INVENTION
[0001] This invention is directed to a turbocharging system for an
internal combustion engine and more particularly to variable
turbine geometry of a turbocharging system.
BACKGROUND OF THE INVENTION
[0002] Turbochargers are a type of forced induction system. They
compress the air flowing into an engine, thus boosting the engine's
horsepower without significantly increasing weight. Turbochargers
use the exhaust flow from the engine to spin a turbine, which in
turn drives an air compressor. Since the turbine spins about 30
times faster than most car engines and it is hooked up to the
exhaust, the temperature in the turbine is very high. Additionally,
due to the resulting high velocity of flow, turbochargers are
subjected to noise and vibration. Such conditions can have a
detrimental effect on the components of the turbocharger,
particularly on the rotating parts such as the turbine rotor, which
can lead to failure of the system.
[0003] Turbochargers are widely used on internal combustion engines
and, in the past, have been particularly used with large diesel
engines, especially for highway trucks and marine applications.
More recently, in addition to use in connection with large diesel
engines, turbochargers have become popular for use in connection
with smaller, passenger car power plants. The use of a turbocharger
in passenger car applications permits selection of a power plant
that develops the same amount of horsepower from a smaller, lower
mass engine. Using a lower mass engine has the desired effect of
decreasing the overall weight of the car, increasing sporty
performance, and enhancing fuel economy. Moreover, use of a
turbocharger permits more complete combustion of the fuel delivered
to the engine, thereby reducing the overall emissions of the
engine, which contributes to the highly desirable goal of a cleaner
environment. The design and function of turbochargers are described
in detail in the prior art, for example, U.S. Pat. Nos. 4,705,463,
5,399,064, and 6,164,931, the disclosures of which are incorporated
herein by reference.
[0004] Turbocharger units typically include a turbine operatively
connected to the engine exhaust manifold, a compressor operatively
connected to the engine air intake manifold, and a shaft connecting
the turbine and compressor so that rotation of the turbine wheel
causes rotation of the compressor impeller. The turbine is driven
to rotate by the exhaust gas flowing in the exhaust manifold. The
compressor impeller is driven to rotate by the turbine, and, as it
rotates, it increases the air mass flow rate, airflow density and
air pressure delivered to the engine cylinders.
[0005] As the use of turbochargers finds greater acceptance in
passenger car applications, three design criteria have moved to the
forefront. First, the market demands that all components of the
power plant of either a passenger car or truck, including the
turbocharger, must provide reliable operation for a much longer
period than was demanded in the past. That is, while it may have
been acceptable in the past to require a major engine overhaul
after 80,000-100,000 miles for passenger cars, it is now necessary
to design engine components for reliable operation in excess of
200,000 miles of operation. It is now necessary to design engine
components in trucks for reliable operation in excess of 1,000,000
miles of operation. This means that extra care must be taken to
ensure proper fabrication and cooperation of all supporting
devices.
[0006] The second design criterion that has moved to the forefront
is that the power plant must meet or exceed very strict
requirements in the area of minimized NO.sub.x and particulate
matter emissions. Third, with the mass production of turbochargers,
it is highly desirable to design a turbocharger that meets the
above criteria and is comprised of a minimum number of parts.
Further, those parts should be easy to manufacture and easy to
assemble, in order to provide a cost effective and reliable
turbocharger. Due to space within the engine compartment being
scarce, it is also desirable that the overall geometric package or
envelope of the turbocharger be minimized.
[0007] U.S. Pat. No. 6,877,955 to Higashimori shows a turbocharger
with a radial flow to the turbine. As shown in FIG. 1, the radial
turbine is provided with the rotor blade unit 100 attached to a
rotation axis and a scroll 102 having a shape similar to a snail.
The rotor blade unit 100 has a hub 101 and a plurality of blades
103 arranged on the hub 101 in a radial direction. A nozzle 104 is
interposed between the scroll 102 and a rotating region of the
blades 103. A gas flows from the scroll 102 into the nozzle 104,
and is accelerated and given rotation force by the nozzle 104 to
produce high velocity flow 105, which flows into the direction of
the rotor axis. The flow energy of the high velocity flow 105 is
converted into the rotation energy by the blades 103 arranged on
the hub 101. The blades 103 exhaust the gas 107 having lost the
energy into the direction of the rotation axis.
[0008] The Higashimori radial flow system suffers from the drawback
of providing only radial flow to the turbine wheel which would not
operate efficiently over a wide range of incident angles. The
application of only radial flow would cause a drop in efficiency at
required engine operating conditions in such a design.
[0009] Thus, there is a need for a turbocharger system, and method
of manufacturing such a system, that effectively and efficiently
controls application of exhaust gas to the turbine wheel.
SUMMARY OF THE INVENTION
[0010] The exemplary embodiments of the turbocharger drive the
turbine wheel utilizing both an axial flow component and a radial
flow component of the exhaust gas in a variable turbine geometry
(VTG) environment. The mixed flow can be provided by a number of
techniques including extended tips of the turbine wheel, secondary
flow and leakage flow.
[0011] In one aspect of the invention, a turbocharger is provided
having a turbine wheel with a plurality of extended tips; and a
variable turbine geometry assembly in fluid communication with the
turbine wheel and having a nozzle ring with a plurality of vanes
movably attached thereto. One or more of the extended tips are
non-parallel with an edge of one or more of the plurality of
vanes.
[0012] In another aspect, a the method is provided that involves
providing an exhaust gas flow to a turbine wheel of a variable
turbine geometry turbocharger, wherein the exhaust gas flow is a
mixed flow having both a radial component and an axial component.
The mixed flow is formed by at least one of leakage gas, secondary
flow and a non-parallel incidence angle of the turbine wheel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention is illustrated by way of example and
not limitation in the accompanying drawings in which like reference
numbers indicate similar parts, and in which:
[0014] FIG. 1 is a schematic representation of a contemporary
turbocharger system with a radial flow to the turbine wheel;
[0015] FIG. 2 is a cross-sectional view of a portion of a
turbocharger in accordance with an exemplary embodiment of the
invention;
[0016] FIG. 3 is a cross-sectional view of a portion of the
turbocharger of FIG. 2;
[0017] FIG. 4 is a cross-sectional view of a portion of a
turbocharger in accordance with another exemplary embodiment of the
invention;
[0018] FIG. 5 is another cross-sectional view of the turbocharger
of FIG. 4; and
[0019] FIG. 6 is a cross-sectional view of portion A of the
turbocharger of FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Embodiments of the invention are directed to mixed flow
along a turbine wheel in a turbocharger for driving a compressor
for delivery of a compressed fluid to an internal combustion
engine. Aspects of the invention will be explained in connection
with a turbine section having a particular turbine wheel geometry,
but the detailed description is intended only as exemplary.
Exemplary embodiments of the invention are shown in FIGS. 2-6, but
the present invention is not limited to the illustrated structure
or application.
[0021] Referring to FIGS. 2-3, a turbocharger 1 has a turbine
housing 2, a center housing 3 and a compressor housing 3a connected
to each other and positioned along an axis of rotation R. The
turbine housing 2 has an outer guiding grid of guide vanes 7 over
the circumference of a support ring 6. The guide vanes 7 may be
pivoted by pivoting shafts 8 inserted into bores of the support
ring 6 so that each pair of vanes define nozzles of selectively
variable cross-section according to the pivoting position of the
vanes 7. This allows for a larger or smaller amount of exhaust
gases to be supplied to a turbine rotor 4.
[0022] The exhaust gases are provided to the guide vanes 7 and
rotor 4 by a supply channel 9 having an inlet 99. The exhaust gases
are discharged through a central short feed pipe 10, and the rotor
4 drives the compressor wheel, impeller or rotor 21 fastened to the
shaft 20 of the wheel. The present disclosure also contemplates one
or more of turbine housing 2, center housing 3 and compressor
housing 3a being integrally formed with each other.
[0023] In order to control the position of the guide vanes 7, an
actuation device 11 can be provided having a control housing 12,
which controls an actuation movement of a pestle member 14 housed
therein, whose axial movement is converted into a rotational
movement of an adjustment or control ring 5 situated behind the
support ring 6. By this rotational movement, the guide vanes 7 may
be displaced from a substantially tangential extreme position into
a substantially radially extending extreme position. In this way, a
larger or smaller amount of exhaust gases from a combustion motor
supplied by the supply channel 9 can be fed to the turbine rotor 4,
and discharged through the axial feed pipe 10.
[0024] Between the vane support ring 6 and a ring-shaped portion 15
of the turbine housing 2, there can be a relatively small space 13
to permit free movement of the vanes 7. The shape and dimensions of
the vane space 13 can be chosen to increase the efficiency of the
turbocharger 1, while allowing for thermal expansion due to the hot
exhaust gases. To ensure the width of the vane space 13 and the
distance of the vane support ring 6 from the opposite housing ring
15, the vane support ring 6 can have spacers 16 formed thereon.
Various other turbocharger components can also be used with
compressor wheel 21 and turbocharger 1.
[0025] Turbocharger 1 can have a mixed flow turbine wheel 4 formed
by a non-zero blade inlet angle, an inlet with a varying radius
from the center axis or a combination of both. The exemplary
embodiment of FIGS. 2-3, illustrates a turbine wheel 4 with an
extended tip 400. The extended tip 400 can be at various angles to
the axis of the turbocharger. The mixed flow turbine wheel 4 to
benefit from both the radial and axial components of the exhaust
gas flow for improved efficiency.
[0026] In a variable turbine geometry turbocharger, the vanes 7 are
the predominant factor controlling the relative turbine wheel blade
incidence angle. As a result, the turbocharger can be forced to
operate over a much wider range of incidence angles. The use of the
mixed flow turbine wheel 4 in combination with a variable turbine
geometry, (i.e., vanes 7) allows the turbocharger 1 to maintain
higher efficiency over a much wider range of incidence angles. In
one embodiment, the variable turbine geometry can compensate for
any increased inertia due to the turbine wheel geometry by
throttling the inlet flow for an improved transient response.
[0027] Referring to FIGS. 4-6, another exemplary embodiment of the
mixed flow turbine wheel is shown and generally represented by
reference numeral 4'. Turbine wheel 4' has one or more extended
tips 400' in proximity to the vanes 7. The extended tips 400' are
at an angle, i.e., non-parallel) with each of the trailing edges of
the vanes 7. In one embodiment, all of the tips of the turbine
wheel 4' are extended tips 400'. In one embodiment, the angle is
between 1 and 60 degrees, preferably between 5 and 45 degrees, and
more preferably between 10 and 30 degrees. However, the present
disclosure contemplates the use of other angles, as well as varying
the angles of the extended tips 400'. The extended tips 400' can
extend into an inlet of the vane space 13. The inlet is represented
generally by broken line 500 in FIG. 5.
[0028] The VTG vanes 7 can control the flow angle into the turbine
wheel 4' and can directly affect the magnitude of the tangential
and radial flow vectors. In one embodiment, where the mixed flow
turbine wheel 4' is less incidence angle sensitive, then the wheel
can maintain a higher overall efficiency over a wider range of
incidence angles (tangential/radial components) than a traditional
radial inflow wheel.
[0029] In another embodiment, a variable turbine geometry
turbocharger can have an axial component of the exhaust gas flow
generated by leakage flow, secondary flow or a combination of both.
This can be used in combination with the extended tips 400 and
400'. In yet another embodiment, the vane 7 can be parallel to the
angle of the turbine wheel. In such an embodiment, the VTG vane
trailing edge is not radial and has a matching angle to the turbine
wheel inlet (or similar angle).
[0030] Although a turbine wheel has been described herein with
great detail with respect to an embodiment suitable for the
automobile or truck industry, it will be readily apparent that the
turbine wheel and the process for production thereof are suitable
for use in a number of other applications, such as fuel cell
powered vehicles. Although this invention has been described in its
preferred form with a certain of particularity with respect to an
automotive internal combustion compressor wheel, it is understood
that the present disclosure of the preferred form has been made
only by way of example and that numerous changes in the details of
structures and the composition of the combination may be resorted
to without departing from the spirit and scope of the
invention.
[0031] It is also contemplated by the present disclosure that the
features of the turbochargers and/or housings can be used with
other types of fluid impelling devices where a particular length of
a diffuser is desired. Such other fluid impelling devices include,
but are not limited to, the following: superchargers; centrifugal
pumps; centrifugal fans; single-stage gas compressors; multistage
gas compressors; and other kinds of devices which generally use one
or more rotating elements to compress gases and/or induce fluid
flow.
[0032] While the invention has been described by reference to a
specific embodiment chosen for purposes of illustration, it should
be apparent that numerous modifications could be made thereto by
those skilled in the art without departing from the spirit and
scope of the invention.
* * * * *