Fluid-cooled electrically-driven compressor and stator housing therefor
阅读说明:本技术 流体冷却的电驱动压缩机及其定子壳体 (Fluid-cooled electrically-driven compressor and stator housing therefor ) 是由 O·乌尔班奇克 于 2019-05-30 设计创作,主要内容包括:描述了一种用于流体冷却的电驱动压缩机的定子壳体。所述定子壳体具有纵向轴线并且包括定子开口,所述定子开口沿所述纵向轴线延伸并且被配置用于接纳电动机的定子。所述定子壳体进一步包括流体室,所述流体室具有流体入口和流体出口、并且在所述纵向轴线的圆周方向上围绕所述定子开口延伸。相对于所述纵向轴线,所述室由径向外壁和径向内壁界定。至少一个流体流偏转器被安排在所述径向外壁与所述径向内壁之间的区域中并且被配置用于使冷却流体流的至少一部分偏转远离所述入口与所述出口之间的最短路径。(A stator housing for a fluid-cooled, electrically-driven compressor is described. The stator housing has a longitudinal axis and includes a stator opening extending along the longitudinal axis and configured to receive a stator of an electric motor. The stator housing further includes a fluid chamber having a fluid inlet and a fluid outlet and extending around the stator opening in a circumferential direction of the longitudinal axis. The chamber is bounded by a radially outer wall and a radially inner wall relative to the longitudinal axis. At least one fluid flow deflector is arranged in a region between the radially outer wall and the radially inner wall and is configured to deflect at least a portion of the cooling fluid flow away from a shortest path between the inlet and the outlet.)
1. A stator housing (16) for a fluid-cooled, electrically-driven compressor (10) of an internal combustion engine, the stator housing (16) having a longitudinal axis (L) and comprising:
a stator opening (64) extending along the longitudinal axis (L) and configured to receive a stator (28) of an electric motor (26), an
A fluid chamber (86) having a fluid inlet (106) and a fluid outlet (108) and extending around the stator opening (64) in a circumferential direction of the longitudinal axis (L), wherein the fluid chamber (86) is delimited by a radially outer wall (90) and a radially inner wall (92) with respect to the longitudinal axis (L), and wherein at least one fluid flow deflector (110) is arranged in a region between the radially outer wall (90) and the radially inner wall (92) and is configured to deflect at least a portion of a cooling fluid flow away from a shortest path between the fluid inlet (106) and the fluid outlet (108).
2. The stator housing (16) of claim 1,
the at least one fluid flow deflector (110) protrudes from at least one of the radially inner wall (92) and the radially outer wall (90) towards an interior of the fluid chamber (86).
3. The stator housing (16) of claim 2,
the at least one fluid flow deflector (110) has a height that increases in a fluid flow direction from the fluid inlet (106) to the fluid outlet (108).
4. The stator housing (16) of any of claims 1 to 3,
the at least one fluid flow deflector (110) is configured to impart a velocity component (A) on at least a portion of the cooling fluid flow, wherein the velocity component (A) extends along the longitudinal axis (L).
5. The stator housing (16) of any of claims 1 to 3,
the at least one fluid flow deflector (110) comprises a front surface having a leading edge (E), wherein the leading edge (E) extends obliquely with respect to at least one of the longitudinal axis (L) and a circumferential direction of the longitudinal axis (L).
6. The stator housing (16) of any of claims 1 to 3,
the at least one fluid flow deflector (110) has a trailing edge (T) extending parallel to the longitudinal axis (L).
7. The stator housing (16) of claim 6,
the trailing edge (T) is configured as a step.
8. The stator housing (16) of claim 5,
for the angle between the leading edge (E) and the trailing edge (T)The following conditions are satisfied:
9. the stator housing (16) of any of claims 1 to 3,
a plurality of fluid flow deflectors (110) is provided and spaced apart in a circumferential direction of the longitudinal axis (L).
10. The stator housing (16) of claim 9,
for the plurality of fluid flow deflectors (110), at least one of the following two conditions is satisfied:
-the fluid flow deflector (110) on the radially outer wall (90) is positioned between two adjacent fluid flow deflectors (110) on the radially inner wall (92) in the circumferential direction; and
-the fluid flow deflector (110) on the radially inner wall (92) is positioned between two adjacent fluid flow deflectors (110) on the radially outer wall (90) in the circumferential direction.
11. The stator housing (16) of any of claims 1 to 3,
an axial distance between the fluid inlet (106) and the fluid outlet (108) along the longitudinal axis (L) is less than 25% of a length of the stator housing (16) along the longitudinal axis (L).
12. The stator housing (16) of any of claims 1 to 3,
the fluid outlet (108) is spaced from the fluid inlet (106) in a circumferential direction of the longitudinal axis (L).
13. The stator housing (16) of any of claims 1 to 3,
the fluid chamber (86) extends less than 360 ° in a circumferential direction of the longitudinal axis (L).
14. The stator housing (16) of any of claims 1 to 3, further comprising the stator (28), wherein the stator (28) is received in the stator opening (64) and defines a radially inner wall (92) of the cooling fluid chamber (86).
15. A fluid-cooled, electrically driven compressor (10) of an internal combustion engine, the electrically driven compressor (10) comprising a stator housing (16) of any one of claims 1 to 3.
16. The stator housing (16) of claim 6,
for the angle between the leading edge (E) and the trailing edge (T)The following conditions are satisfied:
Technical Field
The present disclosure relates to a compressor for an internal combustion engine. More particularly, the present disclosure relates to a stator housing for a fluid-cooled, electrically-driven compressor, and to a fluid-cooled, electrically-driven compressor including such a stator housing.
Background
The compressor delivers compressed air to the intake of the internal combustion engine, allowing more fuel to be burned. As a result, the power density of the engine is increased without significantly increasing the weight of the engine. Thus, the compressor allows a smaller engine to be used that produces the same amount of power as a larger, normally aspirated engine. The use of smaller engines in vehicles has the desirable effect of reducing vehicle mass, improving performance, and reducing fuel consumption. Furthermore, the use of a compressor improves combustion and, thus, reduces emissions.
There are different types of compressors. The exhaust gas turbocharger includes: a turbine housing having an inlet passage connected to an exhaust manifold of an engine, a compressor housing having an outlet passage connected to an intake manifold of an engine; and a bearing housing interconnecting the turbine housing and the compressor housing. The exhaust flow from the exhaust manifold rotatably drives a turbine wheel within a turbine housing. The turbine wheel is connected to the compressor wheel within the compressor housing via a rotor shaft that is rotatably supported within the bearing housing. Thus, rotation of the turbine wheel by the exhaust flow causes rotation of the compressor wheel. The rotating compressor wheel draws ambient air into the compressor housing via a so-called flow guide and compresses the air. Downstream of the compressor wheel, the compressed air enters a diffuser passage from which it is directed to the intake manifold via a compressor shroud.
Electrically driven compressors, sometimes also referred to as electronic superchargers (ebousters), provide an alternative to exhaust gas turbochargers. In an electrically driven compressor, the rotor shaft on which the compressor impeller is arranged is driven by an electric motor instead of the exhaust gas flow. For this purpose, the rotor of the electric motor is rotatably fixed to the rotor shaft, and the stator of the electric motor circumferentially surrounds the rotor. The stator is housed in a stator housing that is fixedly attached to the compressor housing.
Electrically driven compressors tend to heat up significantly during operation, especially at high loads. It has therefore been proposed to circulate cooling fluid through the stator housing to prevent thermal damage. A fluid-cooled, electrically driven compressor of this type is known from WO 2017/192336 a. The stator housing of this compressor comprises a fluid chamber, which is delimited by a radially outer wall and a radially inner wall with respect to the longitudinal axis of the stator housing. The fluid chamber has an inlet for a cooling fluid, and an outlet.
Disclosure of Invention
There is a need for a fluid-cooled, electrically-driven compressor with improved cooling efficiency. There is also a need for a stator housing for such a compressor.
A stator housing for a fluid-cooled, electrically-driven compressor is presented. The stator housing has a longitudinal axis and includes a stator opening extending along the longitudinal axis and configured to receive a stator of an electric motor. The stator housing further includes a fluid chamber having a fluid inlet and a fluid outlet and extending around the stator opening in a circumferential direction of the longitudinal axis. The chamber is bounded by a radially outer wall and a radially inner wall relative to the longitudinal axis. At least one fluid flow deflector is arranged in a region between the radially outer wall and the radially inner wall and is configured to deflect at least a portion of the cooling fluid flow away from a shortest path between the inlet and the outlet.
When the inlet and the outlet are circumferentially spaced apart, the shortest path may extend in a circumferential direction of the longitudinal axis. When the inlet and the outlet are spaced apart in the longitudinal direction, the shortest path may extend in an axial direction of the longitudinal axis. Furthermore, the inlet and outlet may also be spaced apart both in the longitudinal direction of the longitudinal axis and in the circumferential direction, so that the shortest path may have a helical extension (typically less than 360 °).
The at least one fluid flow deflector may be positioned on at least one of the radially outer wall and the radially inner wall. The individual fluid flow deflectors may extend from the inner wall to the outer wall. Alternatively, individual fluid flow deflectors may protrude from only one of the radially inner and outer walls towards the interior of the chamber. Where two or more fluid flow deflectors are provided, one or more of the fluid flow deflectors may protrude from the radially outer wall and one or more of the fluid flow deflectors may protrude from the radially inner wall. The individual flow deflectors may have a maximum height that protrudes through up to 50% or 30% of the distance between the radially outer wall and the radially inner wall in the region of the flow deflector. The individual fluid flow deflectors have a maximum height of between 0.2mm and 5mm (e.g. between 0.5mm and 3 mm), and the radial distance between the radially inner wall and the radially outer wall in this fluid flow deflector region may be greater than the maximum height.
The at least one fluid flow deflector may have a height that increases in a direction of fluid flow (e.g., along a shortest path) from the inlet to the outlet. For example, the at least one fluid flow deflector may define an inclined surface over a region of increased height thereof. This inclined surface may be planar or curved, or may include both curved and planar regions. In the direction of fluid flow, the inclined surface may terminate at a step where the height of the fluid flow deflector is again reduced. Thus, the fluid flow deflector may have a sawtooth profile.
The velocity of the cooling fluid flow may be interpreted as a vector. The at least one fluid flow deflector may be configured to impart a velocity vector component on at least a portion of the cooling fluid flow. For example, the applied velocity vector component may extend along (i.e., parallel to) the longitudinal axis. The applied velocity vector component may typically have a direction different from the direction defined by the shortest path between the entrance and exit. This different direction may be deflected up to 60 ° (e.g., 15 ° to 45 °) from the shortest path direction in the individual fluid flow deflector regions.
The at least one fluid flow deflector may have a front surface relative to the direction of fluid flow. As described above, the front surface may be an inclined surface. The front surface may have a leading edge extending obliquely with respect to at least one of the longitudinal axis and a circumferential direction of the longitudinal axis. For example, the leading edge may not extend parallel to the longitudinal axis and not in a plane extending perpendicular to the longitudinal axis. In some variations, a leading edge of a particular fluid flow deflector is positioned at a transition between one of the radially inner and outer walls and the particular fluid flow deflector.
Additionally or alternatively, the at least one fluid flow deflector may have a trailing edge extending parallel to the longitudinal axis. An angle between the leading edge and the trailing edge
The following conditions may be satisfied:(for example,). The maximum distance between the leading edge and the trailing edge in the circumferential direction may be in the range between 2mm and 20mm (e.g. between 5mm and 10 mm). In some variations, the trailing edge is configured as a step. The height of the step can be reduced. The step may be designed to impart turbulence on at least a portion of the flow of cooling fluid passing through the fluid flow deflector.A plurality of fluid flow deflectors may be provided. The plurality of fluid flow deflectors may be spaced apart (e.g., at equidistant intervals in the circumferential direction) in the circumferential direction of the longitudinal axis. Each of the radially inner and outer walls may be provided with a plurality of fluid flow deflectors projecting therefrom. The fluid flow deflector on the radially outer wall may be positioned circumferentially between two adjacent fluid flow deflectors on the radially inner wall. Additionally or alternatively, the fluid flow deflector on the radially inner wall may be positioned circumferentially between two adjacent fluid flow deflectors on the radially outer wall.
The radial distance between the radially inner wall and the radially outer wall may continuously decrease along the longitudinal axis. In such embodiments, at least one of the inlet and the outlet may be positioned in a region where a radial distance between the radially inner wall and the radially outer wall of the fluid chamber is greater than an average radial distance between the radially inner wall and the radially outer wall along the longitudinal axis.
An axial distance between the inlet and the outlet along the longitudinal axis may be less than 25% of a length of the stator housing along the longitudinal axis. In particular, an axial distance between the inlet and the outlet along the longitudinal axis may be substantially zero.
The outlet may be spaced from the inlet in a circumferential direction of the longitudinal axis. The outlet and the inlet may be provided at opposite ends of the chamber in the circumferential direction. In some variations, the outlet may be spaced more than 180 ° or more than 270 ° from the inlet in a circumferential flow direction of the cooling fluid relative to the longitudinal axis.
The fluid chamber may extend over more than 60 ° or more than 90 ° in the circumferential direction of the longitudinal axis. In particular, the fluid chamber may extend over more than 180 ° or more than 270 ° in the circumferential direction of the longitudinal axis. The chamber may extend less than 360 ° (e.g., less than 350 °) in a circumferential direction of the longitudinal axis. The remaining more than 0 ° or more than 10 ° may be defined by the fluid chamber wall extending longitudinally along the longitudinal axis and the fluid chamber wall extending radially from the radially inner wall to the radially outer wall, respectively. The wall may extend longitudinally the entire length of the fluid chamber.
At least one of the inlet and the outlet is defined by an aperture. The corresponding aperture may extend through a radially outer wall of the fluid chamber.
The stator housing may further comprise a stator of the electric motor, wherein the stator is received in the stator opening. In some variations, the stator may define a radially inner wall of the cooling fluid chamber. For example, the stator may have a substantially cylindrical outer wall defining a radially inner wall of the cooling fluid chamber. The one or more fluid flow deflectors may extend from a substantially cylindrical outer wall of the stator (forming a radially inner wall of the fluid chamber) towards a radially outer wall of the fluid chamber. In other variations, both the radially outer wall and the radially inner wall may be integral components of the stator housing.
There is also provided a fluid-cooled, electrically-driven compressor comprising a stator housing as set forth herein.
In yet another variant, a stator housing for a fluid-cooled, electrically-driven compressor is proposed. The stator housing has a longitudinal axis and includes a stator opening extending along the longitudinal axis and configured to receive a stator of an electric motor. The stator housing further includes a fluid chamber having a fluid inlet and a fluid outlet and extending around the stator opening in a circumferential direction of the longitudinal axis. The chamber is bounded by a radially outer wall and a radially inner wall relative to the longitudinal axis. At least one step is arranged on at least one of the radially outer wall and the radially inner wall and is configured to impart a turbulent flow to the flow of cooling fluid en route from the inlet to the outlet.
The step may extend substantially along the longitudinal axis. The step may have a height that is less than 50%, less than 30%, or less than 15% of the radial distance between the radially inner wall and the radially outer wall. The step may have a height that is greater than 5% or greater than 10% of the radial distance between the radially inner wall and the radially outer wall.
The step may be located at an aft end of the geometry extending from the radially inner wall or the radially outer wall in the circumferential fluid flow direction. This geometry may have a substantially triangular cross-section (e.g., with a sawtooth profile) perpendicular to the longitudinal axis. In some variations, the geometry additionally acts as a fluid flow deflector that deflects the cooling fluid flow away from the shortest path between the inlet and the outlet. In other variations, the geometry may not have this deflection function.
Drawings
Additional aspects and advantages of the present disclosure will be readily appreciated by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIG. 1 is a first cross-sectional view of a fluid-cooled, electrically-driven compressor, wherein the cross-section is taken along a longitudinal axis of the compressor, according to one embodiment of the present disclosure;
FIG. 2 is a second cross-sectional view of the compressor of FIG. 1, wherein the cross-section is taken perpendicular to the longitudinal axis of the compressor;
fig. 3 is a schematic plan view of the fluid flow deflector and illustrates deflection of the fluid flow along the longitudinal axis away from the shortest path;
FIG. 4 is a schematic cross-sectional view of the fluid chamber and illustrates the generation of turbulent flow at the rear end of the fluid flow deflector; and is
FIG. 5 is a table of simulated heat flow related parameters for a comparative fluid chamber without and with a fluid flow deflector.
Detailed Description
Fig. 1 illustrates an embodiment of a fluid-cooled, electrically-driven compressor 10 for an internal combustion engine. The compressor 10 includes a housing assembly 12 formed of a compressor housing 14 and a stator housing 16 connected to one another.
The housing assembly 12 rotatably supports a rotor shaft 20 having an axis of rotation R. A compressor wheel 22 having a plurality of blades is mounted to one end of the shaft 20 that is received in the compressor housing 14. The rotor 24 of the motor 26 is mounted on the opposite end of the shaft 20 relative to the compressor wheel 22. The rotor 24 is accommodated in the stator housing 16 together with a stator 28 of the electric motor 26. During operation of the motor 26, the rotor 24 and shaft 20, as well as the compressor wheel 22, rotate relative to the stator 28, as is known in the art.
Compressor housing 14 includes an inlet passage 40. This inlet passage 40 is also referred to as a flow guide. As the compressor wheel 22 rotates, ambient air is drawn into the compressor housing 14 through the inlet passage 40 and compressed by the compressor wheel 22. Downstream of the compressor wheel 22, the compressed air enters a diffuser passage 42 from which it is directed to the intake manifold of the engine (not shown) via an outlet passage 44 in the form of a volute.
The diffuser passage 42 is defined between a compressor housing body 46 and a back plate 48 of the compressor housing 14. The back plate 48 is substantially disc-shaped and has a diameter substantially greater than a diameter of the compressor wheel 22 to define the diffuser passage 42 that extends away from the compressor wheel 22 in a radial direction.
The back plate 48 includes a central through bore 56 that seats on a tubular projection 58 of the stator housing 14. The rotor shaft 20 extends through this tubular projection 58. A hub 60 (also referred to as a flinger hub) is seated on the rotor shaft 20 for rotation with the rotor shaft 20.
The stator housing 16 has a longitudinal axis L which extends coaxially with the rotation axis R. The stator housing 16 includes a stator housing body 62 having a substantially cylindrical opening 64 extending along the longitudinal axis L and housing the stator 28. A printed circuit board 30 having electrical components in electrical contact with the stator 28 is mounted to the end of the stator housing body 62 facing the compressor housing 14. At the end of the stator housing body opposite the compressor housing 14, the stator opening 64 is closed by a cover 66. In the present embodiment, the cover 66 is attached to the stator housing body 62 via a screw connection. A first rotor bearing 68 for the rotor shaft 20 is disposed within the cover 66 and a second rotor bearing 70 is disposed within the stator housing body 62 at an end thereof opposite the cover 66. The two rotor bearings 68, 70 are configured as ball bearings.
The stator housing body 62 has a hollow substantially cylindrical shape defined by an outer wall 80 and an inner wall 82. The inner wall 82 defines the stator opening 64. A
The
The stator housing body 62 is a metal casting. The
At its end 88B facing the cap 66, the
It should be noted that the
As shown in fig. 2, the longitudinal wall 94 of the stator housing body 62 defines two ends 102, 104 of the
As further shown in fig. 2,
The inlet 106 and the outlet 108 are each positioned adjacent the protrusion 96 of the cap 66. In other words, inlet 106 and outlet 108 are both positioned in areas where the radial distance between radially
As is apparent from fig. 2, a plurality of
Each
To deflect the cooling fluid flow away from the shortest path between the inlet 106 and the outlet 108 (i.e., away from the circumferential direction in this embodiment), the
The velocity of the cooling fluid flow in the circumferential direction of
The leading edge E extends obliquely or diagonally with respect to both the longitudinal axis L and the circumferential direction of the longitudinal axis L. This geometric relationship is shown in fig. 3 by the projection of the longitudinal axis L onto the radially
The trailing edge T of each
Thus, the cooling fluid flow will be partially deflected by each
As shown in fig. 2 and 3, a plurality of
As is apparent from fig. 2, and referring now additionally to fig. 4, the
As illustrated in fig. 4, the trailing edge T of each
Because the
The table of fig. 5 provides a comparison of simulated heat flow related parameters of the
The present invention has been described herein in an illustrative manner, and it is to be understood that modifications and variations are possible in light of the above teachings. It is therefore to be understood that the invention may be practiced in other embodiments while still being covered by the appended claims.
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