Coolant pump for internal combustion engines

Abstract

This disclosure provides a "coolant pump for an internal combustion engine". A pump is provided having a pump housing defining a volute chamber positioned between a central inlet and an impeller face, wherein the housing defines a recess intersecting the face and surrounding an orifice, and the housing sequentially defines a first ramp portion and a second ramp portion, a wall portion, and a protrusion extending into the recess. An impeller is positioned adjacent to the face within the chamber, wherein the impeller is connected to a drive shaft extending through the orifice. A method for cooling a drive shaft sealing member by controlling the flow of fluid through the pump is provided.

Description

Technical Field

[0001] Various embodiments relate to a pump, such as a coolant pump for an internal combustion engine. Background Technology

[0002] Internal combustion engines typically include a cooling system that provides coolant flow through channels formed in the engine block. The cooling system has a pump for driving the coolant flow through the system, and the pump is typically mechanically driven by the crankshaft or other rotating parts of the engine. The pump used with the cooling system may be a centrifugal pump, which includes an impeller located in a pump chamber to drive fluid through the pump. Summary of the Invention

[0003] In one embodiment, a pump is provided having a housing defining a volute chamber extending to an impeller face, wherein the housing defines a notch formed by a dished wall intersecting the face and surrounding a pump drive shaft bore. The housing sequentially defines a first ramp and a second ramp, a wall portion, and a protrusion extending from the dished wall into the notch, wherein the first ramp, the second ramp, and the wall portion intersect the face. A channel is defined by the second ramp, the wall portion, and the dished wall; and the channel is radially positioned relative to the outlet of the volute chamber. The first ramp is positioned between the outlet and the second ramp, and the protrusion is positioned between the wall portion and the outlet.

[0004] In another embodiment, a pump is provided having a pump housing defining a volute chamber positioned between a central inlet and an impeller face, wherein the housing defines a recess intersecting the face and surrounding the bore, and the housing sequentially defines a first ramp portion and a second ramp portion, a wall portion, and a protrusion extending into the recess. An impeller is positioned adjacent to the face within the chamber, wherein the impeller is connected to a drive shaft extending through the bore.

[0005] In another embodiment, a method for cooling a pump drive shaft seal is provided. Fluid flow is guided from the volute chamber through a gap formed between the impeller and the impeller face and into a recess defined by the impeller face and surrounding the pump drive shaft. The fluid flow is guided via a first inclined ramp extending into the recess and via a second inclined ramp extending into the recess. The fluid flow is supplied from the gap through a channel and into the recess. The fluid flow is guided using the end face of a wall portion extending into the recess, thereby increasing the velocity of the fluid flow. A protrusion extending into the recess induces fluid separation. The first ramp, the second ramp, the channel, the wall portion, and the protrusion are arranged sequentially in the recess along the impeller rotation direction, wherein the channel is radially opposite to the outlet of the volute chamber. Attached Figure Description

[0006] Figure 1A schematic diagram of an internal combustion engine and a fluid system according to one embodiment is shown;

[0007] Figure 2 A perspective view of a housing component for a coolant pump according to one embodiment is shown;

[0008] Figure 3 It shows that according to Figure 2 A cross-sectional view of the outer shell components;

[0009] Figure 4 It shows the use of Figure 2 A perspective view of another housing component and impeller of the coolant pump;

[0010] Figure 5 It shows Figure 4 A perspective view of the outer shell components; and

[0011] Figure 6 Explanation is shown Figure 4 The outer shell components relative to Figure 2 A schematic diagram of the flow characteristics of the volute in the outer shell component. Detailed Implementation

[0012] Detailed embodiments of this disclosure are provided herein as needed; however, it should be understood that the disclosed embodiments are merely exemplary and may be embodied in various forms and alternative forms. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized to show details of specific components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching those skilled in the art to employ this disclosure in different ways.

[0013] Figure 1 A schematic diagram of an internal combustion engine 20 is shown. The engine 20 has a plurality of cylinders 22, and one cylinder is shown. The engine 20 can have any number of cylinders, and the cylinders can be arranged in various configurations. The engine 20 has a combustion chamber associated with each cylinder 22. Each cylinder 22 is formed by a cylinder wall 32 and a piston 34. The piston 34 is connected to a crankshaft 36. The combustion chamber and cylinder 22 are in fluid communication with an intake system 38 or an intake manifold 38 and an exhaust manifold 40. An intake valve 42 controls the flow from the intake manifold 38 into the combustion chamber and cylinder 22. An exhaust valve 44 controls the flow from the combustion chamber and cylinder 22 to the exhaust manifold 40. The intake valve 42 and exhaust valve 44 can operate in various ways known in the art to control engine operation.

[0014] Fuel injector 46 delivers fuel directly from the fuel system to cylinder 22, making the engine a direct injection engine. Low-pressure or high-pressure fuel injection systems may be used with engine 20, or in other instances, port injection systems may be used. The ignition system includes a spark plug 48 controlled to provide energy in the form of a spark to ignite the fuel-air mixture in cylinder 22. In other embodiments, other fuel delivery systems and ignition systems or technologies may be used, including compression ignition.

[0015] Engine 20 includes a controller and various sensors configured to provide signals to the controller for controlling the delivery of air and fuel to the engine, ignition timing, power and torque output from the engine, exhaust system, etc. Engine sensors may include, but are not limited to, an oxygen sensor in exhaust manifold 40, an engine coolant temperature sensor, an accelerator pedal position sensor, an engine manifold pressure (MAP) sensor, an engine position sensor for crankshaft position, an air quality sensor in intake manifold 38, a throttle position sensor, and an exhaust temperature sensor in exhaust manifold 40.

[0016] In some embodiments, engine 20 serves as the sole prime mover in a vehicle such as a conventional vehicle or a stop-start vehicle. In other embodiments, the engine may be used in a hybrid vehicle, where an additional prime mover, such as an electric motor, may be used to provide additional power to propel the vehicle.

[0017] Each cylinder 22 can operate in a four-stroke cycle, which includes an intake stroke, a compression stroke, an ignition stroke, and an exhaust stroke. In other embodiments, the engine can operate in a two-stroke cycle. The engine 20 can be configured for spark ignition or compression ignition.

[0018] Engine 20 has a cylinder block 70 and a cylinder head 72 that mate with each other to form a cylinder 22. A cover gasket or other sealing member may be positioned between the cylinder block 70 and the cylinder head 72 to seal the cylinder 22. The cylinder block 70 has a cylinder block top surface that corresponds to and mates with the deck face of the cylinder head 72 along the parting line 74, and the cover gasket may be positioned between the two.

[0019] Engine 20 includes a fluid system 80, such as a cooling system, to remove heat from engine 20. In another instance, fluid system 80 may also serve as a lubrication system to lubricate engine components.

[0020] For the cooling system 80, the heat removed from the engine 20 can be controlled by a cooling system controller or an engine controller. System 80 can be integrated into the engine 20 as one or more cooling sleeves. System 80 has one or more cooling circuits, which may contain coolant as the working fluid. In one example, the cooling circuit has a first cooling sleeve 84 located in the cylinder block 70 and a second cooling sleeve 86 located in the cylinder head 72, wherein sleeves 84 and 86 are in fluid communication with each other. The cylinder block 70 and cylinder head 72 may have additional cooling sleeves. The coolant (such as water, ethylene glycol, or another liquid medium) in the cooling circuit 80 and sleeves 84 and 86 flows from a high-pressure area to a lower-pressure area.

[0021] The fluid system 80 has one or more pumps 88. In the cooling system 80, the pumps 88 supply pressurized fluid in the circuit to fluid passages in the cylinder block 70 and cylinder head 72. The cooling system 80 can be a parallel-flow, split-flow, parallel-split-flow, or other cooling arrangement. The pumps can be driven via mechanical coupling to the crankshaft and / or coupling to an electric motor. The cooling system 80 may also include valves and / or thermostats (not shown) to control the flow rate or pressure of the coolant, or to direct the coolant within the system 80. The cooling passages in the cylinder block 70 may be adjacent to one or more of the combustion chamber and cylinders 22. Similarly, the cooling passages in the cylinder head 72 may be adjacent to one or more of the combustion chamber and cylinders 22, as well as the exhaust port of the exhaust valve 44. Fluid flows from the cylinder head 72 and exits the engine 20 to a heat exchanger 90, such as a radiator, where heat is transferred from the coolant to the environment.

[0022] Figures 2 to 6 A pump 100, such as a centrifugal cooling pump, is shown according to one embodiment. Pump 100 can be used as described above. Figure 1 The pump 88 in engine 20, or may be used as a pump in another vehicle fluid system. Pump 100 has a housing 102 defining a volute chamber 104 or pump chamber. Housing 102 may be formed of various housing members or components that are connected to each other to form a pump and seal the volute chamber. In one example, cover member 106 or housing member is connected to another housing member 108 to form a pump housing. In another example, and as shown, at least a portion of the volute chamber 104 is defined by a cylinder block, and cover member is connected to the cylinder block to form pump 100 and seal volute chamber 104.

[0023] The volute chamber 104 or volute is defined by outer casing members 106, 108 and has an outer wall 110 extending circumferentially around the chamber and a cutwater angle 112 adjacent to the pump outlet 114. As shown, the pump 100 may be a single volute pump. The outer wall 110 may be positioned at a constant or substantially constant distance from the central axis, taking into account various cuts, etc. The outer wall 110 of the volute chamber 104 extends between first and second opposing surfaces 116, 118 of the volute chamber. The first surface 116 may be referred to as the shroud surface, and the second surface 118 may be referred to as the impeller surface.

[0024] Pump 100 has a central pump inlet 120 located generally in the central region of the pump, wherein the pump inlet 120 is defined by an opening surrounded by a shroud surface 116 of the housing. Pump outlet 114 is disposed along the outer wall 110 of the volute chamber. Pump outlet 114 is fluidly connected to an inlet passage for one or more cooling jackets for engine 20 to supply coolant thereto for engine thermal management.

[0025] Impeller 130 is positioned within volute chamber 104 and connected to pump drive shaft 132. During pump operation, impeller 130 rotates within volute chamber 104 via drive shaft 132 to induce fluid flow from pump inlet 120 to pump outlet 114. Impeller 130 may rotate about the central axis of pump 100, or about a drive shaft axis offset from and parallel to the central axis. Pump 100 may be mechanically driven, wherein shaft 132 is mechanically connected to crankshaft 36 of engine, for example via an accessory drive system, such that impeller 130 is driven by crankshaft. In other instances, pump impeller 130 may be electrically driven, for example using an electric motor connected to pump drive shaft 132. Drive shaft 132 extends through bore 133 defined by housing and surrounded by impeller face 118, as described in further detail below.

[0026] Impeller 130 has an impeller inlet 134 and a series of blades or ribs 136. Pump inlet 120 is adjacent to impeller inlet 134, for example, at or near the axis of rotation of impeller 130 and / or the central axis of volute chamber 104. Inlet 134 provides the pump with suction. Fluid flows into pump 100 through inlet 120 and impeller inlet 134. Impeller 130 has a series of blades or ribs 136 and can be an open, semi-open, or closed impeller design. Blades or ribs 136 can extend radially outward, backward, or forward, and can be straight or curved. When impeller 130 is rotated or driven, the fluid in the volute or pump chamber 104 surrounding the impeller also rotates. Impeller 130 forces coolant to move radially outward within volute chamber 104.

[0027] The impeller 130 is sized to extend between the two faces 116, 118, while providing sufficient clearance for the impeller's rotation. In one example, the impeller 130 is spaced from each face by a distance on the order of millimeters. The ends of the shroud face 116 and the impeller blades 136 may be angled or inclined and correspond to each other.

[0028] Coolant flows out of the volute chamber 104 via the discharge passage or outlet passage 114. A water distribution angle 112 is located in the inlet area leading to the discharge passage or at the outlet 114 of the pump volute. The distance from the outer wall 110 of the volute to the axis increases from the water distribution angle 112 to the outlet passage 114 and along the flow direction or the rotation direction of the impeller 130. Note that the impeller 130... Figure 2 , Figure 3 and Figure 6 In the example shown, it rotates counterclockwise, and... Figure 5 The pump rotates clockwise. As the area or volume increases and the speed decreases, this increases the pressure at the pump's discharge area 114. As the pressure at the discharge channel increases, the coolant at the inlet 134 is displaced, which causes a suction effect to draw fluid into the volute chamber 104.

[0029] Pump shaft 132 extends through a hole 133 formed in the pump housing. A recess 140 is defined by a recessed concave wall 142 of the housing and surrounds the hole 133. The recessed concave wall 142 intersects with and extends from the impeller face 118 from the hole 133 to the impeller face 118. A sealing member 144 is positioned around the drive shaft 132 and to prevent fluid from leaving the volute chamber 104 through the hole 133. The sealing member 144 is positioned within the recess 140.

[0030] Pump housing 106 sequentially defines a first ramp 150 and a second ramp 152, a wall portion 154, and a protrusion 156 extending into a recess 140. The first ramp 150, second ramp 152, wall portion 154, and protrusion 156 are circumferentially spaced from each other around the recess 140 and sequentially arranged within the recess in the impeller rotation direction. These features function by inducing crossflow through guiding surfaces to redirect fluid flow and by generating a pressure differential to drive fluid flow from a high-pressure region to a low-pressure region, thereby controlling the fluid flow to guide it across the recess 140 and across the sealing member 144, thus cooling the member. Convective cooling and thermal management of the sealing member 144 are provided by actively inducing fluid flow across the recess 140. Conventional pumps may use flanges or other features; however, fluid in the recess of a conventional pump may have low flow characteristics, which can provide thermal stress on the seal because conductive heat transfer is the primary heat transfer mechanism. The first ramp portion 150, the second ramp portion 152, and the wall portion 154 intersect with the impeller surface 118.

[0031] The first ramp portion 150 may be a wedge-shaped feature. The first ramp portion 150 serves as an initial flow guide in the recess 140. The first ramp portion 150 has an upstream surface 160, such as an inclined surface. The inclined surface may be planar or curved and intersects with the concave wall 142 and the impeller surface 118. The first ramp portion 150 extends to an end region 162, which is located at a first distance from the impeller surface 118 into the recess 140. The first ramp portion 150 is positioned between the outlet 114 and the second ramp portion 152.

[0032] The second ramp portion 152 may be a wedge-shaped feature. The second ramp portion 152 serves as a main flow guide in the recess 140. The second ramp portion 152 has an upstream surface 164, such as an inclined surface. The inclined surface may be planar or curved and intersects with the concave wall 142 and the impeller surface 118. The second ramp portion 152 extends to an end region 166, which is located at a second distance from the impeller surface 118 into the recess 140. The end portion 162 of the first ramp portion 150 is positioned between the impeller surface 118 and the end portion 166 of the second ramp portion 152. The area of ​​the upstream surface 160 of the first ramp portion is smaller than the area of ​​the upstream surface 164 of the second ramp portion.

[0033] The wall portion 154 defines an end face 170 positioned between the impeller face 118 and the bore 133. The end face 170 of the wall portion is radially recessed from the concave wall 142 and may have a first end face 172 and a second end face 174 as shown. The wall portion 154 extends through a beveled section A of the recess 140, for example, ranging from 5 degrees to 70 degrees according to one example, and from 30 degrees to 70 degrees according to another example. The wall portion 154 serves to reduce the cross-sectional area of ​​the recess 140 between the wall portion 154 and the drive shaft 132, relative to the cross-sectional area of ​​the recess 140 on the opposite side between the concave wall 142 and the drive shaft 132, and the wall portion 154 thereby restricts flow in this region.

[0034] The end face 170 of the wall portion can be curved or have another shape. In the example shown, the end face 170 is arc-shaped. The end face 170 can have a constant radius of curvature or it can have a varying radius of curvature. In one example, the end face 170 is an arc-shaped portion positioned concentric with the hole 133 and the concave wall 142. The radius of curvature of the end face 170 is smaller than the radius of curvature of the outer periphery of the concave wall 142.

[0035] Channel 180 is defined between the second ramp portion 152 and the wall portion 154, and intersects with the impeller surface 118. Channel 180 may be defined by the downstream surface 182 or end wall of the second ramp portion 152, the end face 172 or side wall of the wall portion 154, and the concave wall 142. The width of channel 180, or the distance between the second ramp portion and the wall portion, may be approximately half the distance between the first ramp portion 150 and the second ramp portion 152, or less than half the distance between the first ramp portion and the second ramp portion. Channel 180 is positioned radially opposite to the outlet region 114, within 5 to 25 degrees radially opposite to the outlet region 114 according to one example, or within 10 to 15 degrees radially opposite to the outlet region 114 according to another example. Channel 180 serves as a supply inlet for fluid flow into the recess.

[0036] A protrusion 156 extends from the concave wall 142 into the recessed region 140. The protrusion 156 is radially positioned between the orifice 133 and the impeller face 118. The protrusion 156 is positioned upstream of the outlet 114 and between the wall portion 154 and the outlet 114. The protrusion 156 is shown as having a cylindrical shape; however, other shapes are also contemplated. For example, the protrusion 156 may be wedge-shaped, etc. The protrusion 156 acts as a flow restraint feature and can induce a degree of flow separation or volute deflection downstream of the protrusion, which facilitates the fluid flow exiting the recess. The wake region of the protrusion 156 intersects with the radial flow from the channel 180 across the recess 140, and assists in the flow exiting the recess. In one instance, the first ramp portion 150 is positioned radially opposite to the protrusion portion 156, within 5 to 25 degrees radially opposite to the protrusion portion according to one instance, or within 10 to 15 degrees radially opposite to the protrusion portion according to another instance.

[0037] The first ramp portion 150, the second ramp portion 152, and the wall portion 154 are shown flush with the impeller surface 118. In another embodiment, and if there is sufficient available space between the impeller surface and the impeller, at least one of the first ramp portion 150, the second ramp portion 152, and the wall portion 154 may be offset above the impeller surface 118.

[0038] The first ramp portion 150 and the second ramp portion 152, the channel 180, the wall portion 154, and the protrusion 156 cooperate to simultaneously guide and direct fluid flow through the gap 190 between the impeller 130 and the impeller face 118, into the recess 140, across the sealing member 144, and out of the recess 140 near the pump outlet 114 through the gap 190 between the impeller 130 and the impeller face 118. These flow features in the recess 140 are shaped and positioned to control the vector flow field and the pressure field of the fluid, and to provide reduced eddies and increased crossflow in the recess 140. By generating both a pressure differential or pressure imbalance across the recessed region 140 and providing surfaces and features to guide and direct the flow, the pump housing 106 controls the fluid flow across the sealing member 144 to convectively cool the sealing member during pump operation and extend the service life of the seal. Simulation results, along with laboratory correlations, indicate that compared to conventional pumps with radially spaced anti-vortex protrusions in the notch, or pumps without flow control features in the notch, according to Figures 2 to 6 The pump housing 106 offers more than a three-fold improvement in seal life. It should be noted that the rotation of the drive shaft 132 and impeller 130 tends to create a vortex effect on the fluid within the notch 140, where the entry of new fluid is restricted, and the vortex fluid within the notch can heat up during pump operation, acting as a fluid and thermal barrier around the sealing components. The geometry of the housing 106 reduces this vortex while also incorporating crossflow of the fluid.

[0039] While exemplary embodiments have been described above, they are not intended to represent all possible forms of this disclosure. Rather, the language used in this specification is descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of this disclosure. Furthermore, features of various embodiments may be combined to form other embodiments of the invention.

[0040] According to the present invention, a pump is provided having a housing defining a volute chamber extending to an impeller face, the housing defining a notch formed by a concave wall intersecting the face and surrounding a pump drive shaft bore, the housing sequentially defining a first ramp portion and a second ramp portion, a wall portion, and a protrusion extending from the concave wall into the notch, wherein the first ramp portion, the second ramp portion, and the wall portion intersect the face, wherein a channel is defined by the second ramp portion, the wall portion, and the concave wall, the channel being radially positioned relative to an outlet of the volute chamber, wherein the first ramp portion is positioned between the outlet and the second ramp portion, and the protrusion is positioned between the wall portion and the outlet.

[0041] According to one embodiment, the first slope portion and the second slope portion are respectively defined by a first upstream inclined surface and a second upstream inclined surface, wherein the area of ​​the first inclined surface is smaller than the area of ​​the second inclined surface; and wherein the width of the channel is less than half of the distance between the first slope portion and the second slope portion.

[0042] According to one embodiment, the wall portion defines a curved end face that intersects with the concave wall and the impeller surface, wherein the radius of curvature of the end face is smaller than the radius of curvature of the outer periphery of the concave wall.

[0043] According to the present invention, a pump is provided having: a pump housing defining a volute chamber positioned between a central inlet and an impeller face, the housing defining a recess intersecting the face and surrounding the hole, the housing sequentially defining a first ramp portion and a second ramp portion, a wall portion and a protrusion extending into the recess; and an impeller positioned adjacent to the face within the chamber, the impeller being connected to a drive shaft extending through the hole.

[0044] According to one embodiment, the first ramp portion, the second ramp portion, the wall portion, and the protrusion are spaced apart from each other circumferentially around the recess.

[0045] According to one embodiment, the first ramp portion, the second ramp portion, and the wall portion intersect with the impeller surface.

[0046] According to one embodiment, the protrusion is radially positioned between the hole and the impeller surface.

[0047] According to one embodiment, the notch is defined by a concave wall extending from the hole to the impeller surface.

[0048] According to one embodiment, the first ramp portion and the second ramp portion are defined by a first inclined surface and a second inclined surface, respectively, and each inclined surface intersects with the concave wall and the impeller surface.

[0049] According to one embodiment, the area of ​​the first inclined surface is smaller than the area of ​​the second inclined surface.

[0050] According to one embodiment, the wall portion is defined at an end face positioned between the impeller surface and the bore.

[0051] According to one embodiment, the end face extends along an arcuate portion concentric with the hole.

[0052] According to one embodiment, a channel is defined between the second ramp portion and the wall portion, wherein the channel is radially opposite to the outlet of the volute chamber.

[0053] According to one embodiment, the channel is defined by the end wall of the second ramp and the side wall of the wall portion.

[0054] According to one embodiment, the width of the channel is less than half the distance between the first ramp and the second ramp.

[0055] According to one embodiment, the protrusion is located upstream of the outlet.

[0056] According to one embodiment, the first ramp portion and the protrusion portion are positioned radially opposite each other.

[0057] According to one embodiment, the pump housing defines a single volute.

[0058] According to one embodiment, the invention is further characterized by a sealing member surrounding the shaft and positioned within a recess; wherein the first and second ramp portions, the wall portion, and the protrusion are configured to guide fluid flow across the recess and through the sealing member to cool the member.

[0059] According to the present invention, a method for a cooling pump drive shaft seal includes: guiding a fluid flow from a volute chamber through a gap formed between an impeller and an impeller face and into a recess defined by the impeller face and surrounding the pump drive shaft; guiding the fluid flow via a first inclined ramp extending into the recess; guiding the fluid flow via a second inclined ramp extending into the recess; supplying a fluid flow from the gap through a channel and into the recess; guiding the fluid flow using an end face of a wall portion extending into the recess, thereby increasing the velocity of the fluid flow; and initiating fluid separation using a protrusion extending into the recess; wherein the first ramp, the second ramp, the channel, the wall portion, and the protrusion are sequentially arranged in the recess along the impeller rotation direction, the channel being radially opposite to the outlet of the volute chamber.

Claims

1. A pump comprising: A pump housing is defined to be positioned in a volute chamber between a central inlet and an impeller face. The housing defines a recess that intersects the impeller face and surrounds the hole. The housing sequentially defines a first ramp portion and a second ramp portion, a wall portion, and a protrusion extending into the recess. as well as An impeller is positioned adjacent to the impeller surface within the chamber, and the impeller is connected to a drive shaft extending through the orifice; A channel is defined between the second ramp portion and the wall portion, wherein the channel is radially opposite to the outlet of the volute chamber; and The width of the channel is less than half the distance between the first ramp and the second ramp.

2. The pump of claim 1, wherein the first ramp, the second ramp, the wall portion, and the protrusion are circumferentially spaced apart from each other around the recess.

3. The pump of claim 1, wherein the first ramp portion, the second ramp portion, and the wall portion intersect the impeller surface.

4. The pump of claim 1, wherein the protrusion is radially positioned between the hole and the impeller surface.

5. The pump of claim 1, wherein the notch is defined by a concave wall extending from the hole to the impeller surface.

6. The pump of claim 5, wherein the first ramp portion and the second ramp portion are respectively defined by a first inclined surface and a second inclined surface, each inclined surface intersecting the concave wall and the impeller surface, and wherein the area of ​​the first inclined surface is smaller than the area of ​​the second inclined surface.

7. The pump of claim 6, wherein the wall portion defines an end face positioned between the impeller face and the orifice.

8. The pump of claim 7, wherein the end face extends along an arcuate portion concentric with the hole, and wherein the radius of curvature of the end face is smaller than the radius of curvature of the outer periphery of the concave wall.

9. The pump of claim 1, wherein the channel is defined by the end wall of the second ramp and the side wall of the wall portion.

10. The pump of claim 1, wherein the protrusion is positioned upstream of the outlet, and wherein the first ramp is positioned radially opposite to the protrusion.

11. The pump of claim 1, wherein the pump housing defines a single volute.

12. The pump of claim 1, further comprising a sealing member surrounding the shaft and positioned within the recess; The first and second ramp portions, the wall portion, and the protrusion are configured to guide fluid flow across the notch and through the sealing member to cool the member.

13. A method for creating a seal for a cooling pump drive shaft, comprising: The fluid flow is guided from the volute chamber through the gap formed between the impeller and the impeller surface and into the notch defined by the impeller surface and surrounding the pump drive shaft; The fluid flow is guided via a first inclined ramp extending into the recess; The fluid flow is guided via a second inclined ramp extending into the recess; Fluid is supplied from the gap through the channel and into the notch; The fluid flow is guided by the end face of the wall portion extending into the notch, thereby increasing the velocity of the fluid flow; and Fluid separation is initiated by using a protrusion extending into the notch; The first inclined ramp, the second inclined ramp, the channel, the wall portion, and the protrusion are sequentially arranged in the recess along the impeller rotation direction, and the channel is radially opposite to the outlet of the volute chamber; and The width of the channel is less than half the distance between the first inclined ramp and the second inclined ramp.

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