Rear-wheel drive EGR pump

Abstract

An exhaust gas recirculation system for an internal combustion engine includes an electric motor and an exhaust gas recirculation pump coupled to the electric motor. The exhaust gas recirculation pump includes a housing that defines an internal volume, and a rotor is located within the internal volume and connected to the electric motor. A bearing plate is mounted to the housing, and the bearing plate and an outer cover mounted to the bearing plate define an oil cavity for lubricating various parts of the transmission assembly. The housing includes a coolant passage to reduce heat transfer from the exhaust gas recirculation pump to the electric motor.

Description

Technical Field

[0001] Cross - reference to related applications This application claims the priority of Indian Provisional Patent Application No. 202311028988 filed on April 21, 2023, the disclosure of which is hereby incorporated by reference in its entirety into this specification.

[0002] This application relates to a rear - wheel - drive EGR pump.

[0003] With the increasing awareness of environmental considerations regarding automotive exhaust gases and the increasingly stringent exhaust gas regulations, both automotive manufacturers and consumers are seeking automobiles with low emissions of harmful exhaust gases. Many automobiles that use internal combustion engines (e.g., diesel engines, gasoline engines, or two - stroke engines) are equipped with an exhaust gas recirculation (EGR) device that recirculates exhaust gas into the engine and mixes it with the fuel (charge) in the cylinder. The EGR gas mixed with the air and fuel supplied to the engine promotes the overall combustion of the fuel. As a result, the exhaust gas emissions can be reduced. By including a separate EGR pump, fuel efficiency improvement can be achieved compared to conventional systems that drive the EGR flow using a turbocharger with an additional expensive EGR valve. Furthermore, a separate EGR pump can fully control the EGR flow. In the case of a diesel engine, by using a separate EGR pump, the EGR valve can be eliminated, and a complex variable - capacity turbocharger can be replaced with a fixed - capacity turbocharger optimized to supply supercharged air. A separate EGR pump can reduce the pumping work of the engine and improve fuel efficiency. recirculation: EGR) device is installed. The EGR gas mixed with the air and fuel supplied to the engine promotes the overall combustion of the fuel. As a result, the exhaust gas emissions can be reduced. By including a separate EGR pump, fuel efficiency improvement can be achieved compared to conventional systems that drive the EGR flow using a turbocharger with an additional expensive EGR valve. Furthermore, a separate EGR pump can fully control the EGR flow. In the case of a diesel engine, by using a separate EGR pump, the EGR valve can be eliminated, and a complex variable - capacity turbocharger can be replaced with a fixed - capacity turbocharger optimized to supply supercharged air. A separate EGR pump can reduce the pumping work of the engine and improve fuel efficiency.

[0004] However, when exhaust gas containing particulate matter such as soot and / or water vapor (resulting from the combustion process of the fuel supplied to the engine) enters the engine intake manifold, soot may accumulate on various engine components, potentially leading to performance degradation.

Summary of the Invention

[0005] This disclosure relates to an improved exhaust gas recirculation (EGR) system that receives exhaust gases from an engine system (in some examples via an intercooler) and recirculates those exhaust gases back into the engine, as described herein. In some examples, the EGR system includes channels for circulating coolant. In some examples, the EGR system includes channels and cavities for circulating and retaining oil.

[0006] Accordingly, this application describes an exhaust gas recirculation system for an internal combustion engine, the exhaust gas recirculation system comprising: an electric motor located in an electric motor housing; an exhaust gas recirculation pump coupled to the electric motor, the exhaust gas recirculation pump including a pump housing that defines the internal volume; a plurality of rotors located within the internal volume, the first of which rotors is connected to the electric motor; and a transmission assembly including a drive gear attached to the first rotor, the transmission assembly including a driven gear that meshes with the drive gear, the driven gear being coupled to a second of which rotors The transmission assembly is positioned on the opposite side of the pump housing from the electric motor; a lip seal positioned around the rotor shaft and in contact with the periphery of the rotor shaft, the rotor shaft being integral with either the first rotor or the second rotor; a pair of piston ring seals positioned around the rotor shaft and in contact with the periphery of the rotor shaft, the lip seal being positioned between a first set of bearings and the pair of piston ring seals, the first set of bearings being positioned between the gears and the lip seal; and the transmission assembly is positioned on the opposite side of the pump housing from the electric motor; a lip seal positioned around the rotor shaft and in contact with the periphery of the rotor shaft; and a pair of piston ring seals being positioned between the gears and the lip seal.

[0007] In one embodiment, the exhaust gas recirculation system further includes a coolant passage that is at least partially defined by a pump housing, the coolant passage being defined around at least a second set of bearings.

[0008] In one embodiment, the pump housing defines a fin structure within the coolant flow path.

[0009] In one embodiment, the fin structure is formed radially around a second set of bearings.

[0010] In one embodiment, the exhaust gas recirculation system further includes a motor mounting adapter; a coolant inlet formed in the motor mounting adapter; and a coolant outlet formed in the adapter, wherein the coolant inlet and coolant outlet are configured to introduce coolant and at least partially define the flow path of the coolant.

[0011] In one embodiment, the exhaust gas recirculation system further includes a bearing plate mounted on the pump housing, the bearing plate including journals formed to receive a first set of bearings.

[0012] In one embodiment, the bearing plate and the outer cover attached to the bearing plate define the oil cavity.

[0013] In one embodiment, the transmission assembly is located within the oil cavity.

[0014] In one embodiment, the bearing plate includes at least one oil inlet extending to at least one oil outlet, the at least one oil outlet being defined by an outer cover, and the oil lubricates a second set of bearings and transmission assemblies.

[0015] In one embodiment, the oil outlet is positioned to allow oil to be discharged from the oil cavity by gravity.

[0016] In one embodiment, the exhaust gas recirculation system further includes: a shelf defined by a pump housing; a pocket defined by at least the shelf, a second bearing assembly, a motor mounting adapter, and an electric motor shaft; and a biasing element disposed within the pocket and surrounding the electric motor shaft.

[0017] This summary is provided to introduce some of the concepts further explained in the detailed description below in a simplified form. This summary is not intended to identify the principal or essential features of the invention as described in the claims, nor is it intended to be used to limit the scope of the invention as described in the claims. [Brief explanation of the drawing]

[0018] The following drawings illustrate examples that are neither limiting nor exhaustive. [Figure 1] This is a perspective view of an EGR pump system according to one embodiment. [Figure 2] Figure 1 is a front exploded view of an EGR pump system according to one embodiment. [Figure 3] Figure 1 is a rear exploded view of an EGR pump system according to one embodiment. [Figure 4] This is a perspective view of an EGR pump according to one embodiment. [Figure 5] This is a perspective view of the EGR pump with the outer cover of the transmission assembly removed, according to one embodiment. [Figure 6A] This is a front view of the EGR pump with the outer cover of the transmission assembly removed, according to one embodiment. [Figure 6B] This is a front view of the EGR pump with the outer cover and gears of the transmission assembly removed, according to one embodiment. [Figure 7] This is a rearward perspective view of the bottom of an EGR pump with the motor mounting adapter removed, according to one embodiment. [Figure 8] This is a rearward perspective view of the top surface of an EGR pump with the motor mounting adapter removed, according to one embodiment. [Figure 9] This is a rear view of an EGR pump with the motor mounting adapter removed, according to one embodiment, showing the flow path of the cooling fluid. [Figure 10]Rear perspective view of a motor mounting adapter for an EGR pump and an electric motor according to one embodiment. [Figure 11] Front perspective view of a motor mounting adapter for an EGR pump and an electric motor according to one embodiment. [Figure 12] Rear perspective view showing a part of the EGR pump system of FIG. 1 (including a part of the EGR pump and the electric motor) according to one embodiment. [Figure 13] Front perspective view showing a part of the EGR pump system of FIG. 1 (including the electric motor and the coolant seal plate) according to one embodiment. [Figure 14] Front perspective view of a part of the EGR pump system of FIG. 1 (including the electric motor) according to one embodiment. [Figure 15] Horizontal cross-sectional view of the EGR pump system of FIG. 1 according to one embodiment. [Figure 16] Part of the horizontal cross-sectional view of the EGR pump system of FIG. 15 according to one embodiment. [Figure 17] Part of the horizontal cross-sectional view of the EGR pump system of FIG. 15 according to one embodiment. [Figure 18] Vertical cross-sectional view of the EGR pump system of FIG. 1 according to one embodiment. Detailed Description of the Invention

[0019] In the following detailed description, reference is made to the accompanying drawings which form a part hereof. The accompanying drawings illustrate specific embodiments or examples by way of illustration. These aspects can be combined, other aspects can be utilized, and structural changes can be made without departing from the present disclosure. The embodiments can be implemented as a method, a system, or an apparatus. Accordingly, the following detailed description should not be construed in a limiting sense, and the scope of the present disclosure is defined by the appended claims and their equivalents.

[0020] Vehicles using internal combustion engines may include exhaust gas recirculation (EGR), which recirculates exhaust gases into the engine and mixes them with fuel in the cylinders. The EGR gas, mixed with air and fuel into the engine, promotes overall fuel combustion. The mixing of air and fuel with EGR gas into the engine helps control the maximum combustion temperature of the fuel in the engine, which can reduce exhaust gas emissions. By including a separate EGR pump, fuel efficiency can be improved compared to conventional systems that drive the EGR flow using a turbocharger with an added expensive EGR valve. Furthermore, a separate EGR pump allows for complete control of the EGR flow. In diesel applications, using a separate EGR pump eliminates the EGR valve and replaces a complex variable displacement turbocharger with a fixed displacement turbocharger optimized for supplying supercharging air. A separate EGR pump can reduce engine pumping work and improve fuel efficiency.

[0021] However, if exhaust gases containing particulate matter such as soot and / or water vapor (generated as a result of the combustion process of fuel supplied to the engine) enter the engine intake manifold, soot can accumulate on various engine components, potentially leading to performance degradation. Water vapor is often released into the environment through the exhaust system. However, in systems utilizing an EGR pump, some of the water vapor in the exhaust gas may be recirculated into the engine's intake manifold. Water vapor can act as a carrier for exhaust particulate matter such as soot. As soot accumulates, it can build up on various components, potentially leading to performance degradation.

[0022] Various parts of the EGR pump disclosed herein may be exposed to high-temperature exhaust gases. For example, the rotor inside the pump may come into contact with exhaust gases at temperatures such as approximately 220°C to 300°C. In such situations, high temperatures can demagnetize components of the electric motor, causing torque loss. Furthermore, high temperatures can adversely affect the mechanical components of the EGR pump, including changes in heat treatment and material properties.

[0023] The present invention relates to an improved exhaust gas recirculation (EGR) system that receives exhaust gases from an engine system and recirculates the exhaust gases back into the engine, as described herein. In some examples, the EGR system includes channels for circulating coolant (to reduce heat transfer from the EGR pump rotor to the electric motor driving the EGR pump, thereby preventing the motor from overheating). In some examples, the EGR system includes channels and cavities for oil flow and retention (to lubricate various components of the EGR pump for safe and long-term operation in the EGR system environment). In some examples, the disclosed EGR pump prevents soot buildup.

[0024] The EGR pump system described herein can deliver exhaust gas from the engine's exhaust manifold to the intake manifold at a controlled, variable flow rate. To deliver the exhaust gas, the EGR system can use an EGR pump coupled to an electric motor. The electric motor can control the EGR flow rate by managing the motor speed, and consequently the pump speed and the exhaust gas flow rate.

[0025] These examples and others are explained in more detail below with reference to Figures 1 to 18.

[0026] Based on the principles of this disclosure, the figure shows an example of an exhaust gas recirculation pump (EGR pump) system 10. The EGR pump system 10 includes an electric motor 12 containing various motor components within a motor housing 13. In some examples, the electric motor 12 may be a brushless DC motor. In other examples, the electric motor 12 may be another suitable type of electric motor.

[0027] The EGR pump (which can also be configured as a Roots-type device) 14 is coupled to an electric motor 12. The EGR pump 14 includes a pump housing 16 that defines an internal volume 17. The rotor 18 is located within the internal volume and is connected to the electric motor 12 (at one end of the electric motor shaft 84) (at the first end of the rotor shaft 82).

[0028] In some examples, the pump housing 16 and other components disclosed herein mounted to the pump housing 16 may be made of ductile cast iron. In other examples, the pump housing 16 and other components disclosed herein mounted to the pump housing 16 may be made of cast iron, alloy steel, non-alloy steel, stainless steel, brass, other metals or metal alloys, or other materials. In some examples, the rotor 18 may be made of ductile cast iron, cast iron, alloy steel, non-alloy steel, stainless steel, brass, other metals or metal alloys, or other materials. In some examples, the rotor 18 may be coated with a coating suitable for the environment of the EGR system 100. In some examples, such a coating may be polymer-based or metal-based. In some examples, various components of the EGR pump system 10 may be formed by casting. In some examples, various components of the EGR pump system 10 may be formed by machining.

[0029] In one embodiment, the EGR pump system may be oriented horizontally (as in a particular embodiment shown in the illustration), and the electric motor 12 may be positioned horizontally adjacent to the EGR pump 14. In one embodiment, the EGR pump system may be oriented vertically, and the electric motor 12 may be positioned vertically above the EGR pump 14 and rotor 18. In one embodiment, the electric motor 12 may be positioned opposite the transmission assembly 50 of the EGR pump 14.

[0030] The exhaust gas recirculation pump system 10 includes a pump housing 16 that defines an internal volume 17 surrounding the rotor 18. While different numbers of rotors 18 are possible, the illustrated embodiment includes two (a pair) rotors 18. Each rotor includes a number of lobes 19 projecting radially outward from the rotor shafts 82, 83 and extending longitudinally along the rotor shafts 82, 83. While different numbers of lobes 19 are possible, the illustrated embodiment includes three lobes 19 in each rotor 18.

[0031] The pump housing 16 may have a shape (in some examples, substantially elliptical, rectangular, or cylindrical) configured to accommodate the lobes 19 of the rotor 18. The pump housing 16 includes a housing end face 20 connected to the housing side wall 22. The portion of the housing 24 opposite the housing end face 20 is open.

[0032] In one example, EGR gas enters the pump housing 16 through the gas inlet 60 and exits the pump housing 16 through the gas outlet 62. In some examples, the gas inlet 60 and gas outlet 62 may be the same shape or different shapes. In the particular example shown, the gas inlet 60 and gas outlet 62 are rectangular with rounded corners, but other shapes are also possible, including circular, oval, elliptical, square, rectangular, or other suitable shapes. In some examples, the gas inlet 60 and gas outlet 62 are symmetrical, and gas adapters, pipes, or other features can be attached in various orientations. In some examples, the gas inlet 60 and gas outlet 62 are symmetrically positioned in the pump housing 16. In some examples, the path through which gas flows from the internal volume 17 through the gas inlet 60 and / or gas outlet 62 includes curved and straight sections. In some examples, this straight section of the gas inlet 60 and gas outlet 62 is parallel to the oil outlet 48.

[0033] In some examples, an EGR gas outlet adapter may be attached to the pump housing 16 to guide the EGR gas that exits the EGR pump 14 and is discharged from the gas outlet 62. In one embodiment, the outlet adapter is modular, so that various shapes can be attached to the EGR pump 14 to suit different system configurations. In some configurations, the gas inlet 60 and gas outlet 62 may be positioned in opposite directions so that the same amount of EGR gas flows regardless of the direction the EGR pump 14 is pumped, and the EGR pump 14 can achieve the same performance.

[0034] The electric motor 12 includes a motor housing 13 with a coolant passage 26 formed inside. The coolant passage 26 provides thermal protection, removes heat from the electric motor 12, and is connected to the coolant path. The coolant passage 26 can have various shapes. In some examples, the coolant passage 26 can be separated by spokes or separators 49. The coolant path can be connected to an engine coolant path, such as coolant from an engine radiator. Coolant enters through a coolant inlet 31 and cools the inverter associated with the electric motor 12. A coolant seal 61 is provided to contain the coolant.

[0035] The electric motor 12 includes a cooling plate 29 that is attached to, connected to, or fixed to the electric motor housing on the motor-facing surface 32 and connected to the pump housing 16 (via a motor mounting adapter 27) on the pump-facing surface 34. The cooling plate 29 includes a coolant inlet 31 and an outlet 33. The coolant inlet 31 and outlet 33 of the cooling plate 29 are aligned with the coolant inlet 46 and outlet 47 of the electric motor 12, respectively.

[0036] In one embodiment, the electric motor shaft 84 is joined to the first end of the drive rotor shaft 82, which extends along the axis X. The drive rotor shaft 82 supports and rotates the first rotor 18.

[0037] In one embodiment, the electric motor shaft 84 includes a pair of separate extension wedges 86. The drive rotor shaft 82 includes a pair of separate extension wedges 92 extending from its ends. A connector 94 connects the motor extension wedges 86 and the rotor extension wedges 92. The connector 94 includes a central circular body 96, around which wedge-shaped bodies 98 are formed radially. The wedge-shaped bodies 98 define openings within which the extension wedges 86 and 92 are positioned, connecting the drive rotor shaft 82 and the electric motor shaft 84.

[0038] In some examples, the connector 94 forms at least part of an insulating coupling that prevents heat transfer from the rotor 18 and drive rotor shaft 82 to the electric motor shaft 84 and electric motor 12. In one embodiment, the insulating coupling may include a polymer material such as polyimide, which may include reinforcing materials such as carbon fibers or glass fibers.

[0039] In one embodiment, the EGR pump 14 includes bearings 28 for assisting the rotation of the rotor shafts 82, 83. These bearings 28 require or may benefit from lubrication, for example, by oil. In some examples, the bearings 28 may be sealed grease bearings that do not require an external oil lubrication source and can eliminate the possibility of oil blow-by into the rotor cavity. In some examples, the bearings 28 may be ball bearings or other suitable types of bearings.

[0040] In some examples, the pump housing 16 may include an extension shelf 21 that extends beyond the rear end of the bearing assembly 28 toward the electric motor 12. This shelf 21 defines a pocket 23 for housing a biasing element 25. In some examples, the biasing element 25 may be a type of spring. In some examples, the biasing element 25 surrounds the outer circumference of the rotor shafts 82, 83. In some examples, the biasing element 25 may contact the bearing assembly 28 on a first surface and contact the motor mounting adapter 27 on a second surface.

[0041] In some examples, the rotor shafts 82, 83 include circumscribing grooves containing a pair of piston ring seals 35 to prevent the movement of coolant and / or oil between the electric motor 12 and the internal volume 17 of the EGR pump 14.

[0042] In some examples, the pump housing 16 defines a coolant channel 69 that defines at least a portion of the coolant flow path (CFP) at the pump housing end face 20. In some examples, the coolant channel 69 includes a fin structure 70 formed thereon. The fin structure 70 increases the contact surface area between the material of the pump housing 16 and the coolant, thereby increasing heat removal from the pump housing 16 by the high-temperature EGR gas in the EGR pump 14. The fin structure 70 also increases turbulent mixing of the coolant, thereby increasing heat transfer from the pump housing 16. The fin structure 70 can be formed in various patterns around the bearing 38. In some examples, as shown, the fin structure 70 is distributed radially around the bearing 38. In some examples, the fins 70 are formed around the bearing 38 and perpendicular to the bearing 38. In some examples, additional fins 70 extending toward the bearing 38 are also formed on the pump housing 16. In some examples, the coolant channel 69 also includes one or more bypass structures 71 for guiding the flow of coolant fluid along the CFP. In some examples, the separator 75 divides a portion of the coolant channel 69, thereby allowing the coolant to be guided through the coolant channel 69 from one start point to the end point in a desired CFP, so that the CFP forms a start point and an end point.

[0043] As a drive rotor shaft 82, the drive rotor shaft 82 rotates a drive gear 52, which is part of the transmission assembly 50. The drive gear 52 meshes with a driven gear 54, which rotates with the driven rotor shaft 83 at its first end (extending along axis Y).

[0044] The exhaust gas recirculation pump system 10 includes a bearing plate 36 mounted on the open end 24 of the pump housing 16. In some examples, the bearing plate 36 includes a journal 37 that receives a bearing 38. The bearing plate 36 and the outer cover 40 define an oil cavity 42. In some examples, the outer cover 40 can be of various shapes.

[0045] The EGR pump system 10 includes a transmission assembly 50 which includes a drive gear 52 that meshes with a driven gear 54. The drive gear 52 is coupled to a drive rotor shaft 82. The driven gear 54 meshes with the drive gear 52 and is coupled to a driven rotor shaft 83. In one embodiment, the transmission assembly 50 is located in the oil cavity 42 on the opposite side of the pump housing 16 from the electric motor 12.

[0046] In some examples, snap rings 53 are located around the rotor shafts 82 and 83 behind the gears 52 and 54 to prevent lateral movement of the bearing 38 and the transmission 50. In some examples, a transmission retainer plate is provided around the bearing 38 and attached to the bearing plate 36 to prevent lateral movement of the bearing 38 and the transmission 50.

[0047] Oil (e.g., from the engine or another source) enters the oil cavity 42 through the oil inlet 44 to lubricate and cool the bearings 38 and the transmission 50. In some examples, the oil inlet 44 may include a banjo fitting, a threaded connection, a welded connection, a quick-connect fitting, or other suitable connection mechanism. In some examples, the bearings 38 (assisting the rotation of the rotor shafts 82, 83) may be open bearings lubricated by oil. The oil is discharged from the oil cavity 42 through a single oil outlet 48. In some examples, the oil outlet 48 may be located in the center of the oil cavity at the bottom of the outer cover 40, and the bottom surface of the outer cover 40 is sloped to guide the oil downward toward the oil outlet 48 so that the oil is discharged from the oil cavity 42 by gravity as needed. In some examples, the oil outlet 48 has a circular orifice. In some examples, the position or shape of the oil outlet 48 may differ (for example, if the EGR pump system is not oriented horizontally), and oil can be drained from the oil cavity 42 by gravity. In some examples, the oil drained from the oil outlet 48 may be directed to the engine's crankcase. The bearing plate 36 is provided with a seal 57 to seal the oil cavity 42.

[0048] Oil can be introduced into the transmission area using various oil dispersion structures. In some examples, the oil dispersion structure may be oil slots formed in the bearing plate 36. The oil moves through the slots and comes into contact with the drive gear 52 and the driven gear 54, lubricating the gears 52, 54 and the bearing 38.

[0049] In some examples, the oil dispersion structure may be located above or below the oil cavity 42 and may be an oil conduit 55 formed in the bearing plate 36. The oil conduit is provided with holes 59 so that oil can move through the holes and come into contact with the drive gear 52 and driven gear 54 to lubricate the gears 52, 54 and the bearing 38.

[0050] In some examples, a series of leak prevention mechanisms may be installed to prevent oil from leaking from the oil cavity 52 into the space defined by the pump housing 16. In some examples, a lip seal 85 is provided on the side closer to the bearing 38, making contact with the rotor shafts 82, 83 at one, two, or more points. A groove 87 is provided on the side closer to the lobes of the rotor 18, which may house a pair of piston ring seals 89 that make contact with the rotor shafts 82, 83.

[0051] The driven rotor shaft 83 supports and rotates the second rotor 18. At its second end, the driven rotor shaft 83 is surrounded by the driven end interface 73 of the motor mounting adapter 27.

[0052] The EGR pump 14 includes a motor mounting adapter 27. The motor mounting adapter 27 includes a motor mounting portion 65, one end of which is attached to the electric motor 12 and the other end of which is attached to the EGR pump 14. The motor mounting portion 65 includes a drive opening 64 that accommodates the passages for the rotor shaft 82 and the electric motor shaft 84.

[0053] The motor mounting adapter includes an adjacent mounting portion 66 that is attached to the EGR pump 14. The adjacent mounting portion 66 includes a driven end interface 73.

[0054] The motor mounting adapter 27 has a coolant inlet 67 and a coolant outlet 68 formed to introduce coolant into the coolant cavity 42 and define the flow path of the coolant. The coolant inlet 67 and coolant outlet 68 are formed to open on the opposite side of the separator 75. The coolant inlet 67 and coolant outlet 68 are defined by bores formed through the adapter 27. These bores may be formed at an angle so as not to be perpendicular to the adapter 27. The coolant inlet 67 and coolant outlet 68 correspond to and are aligned with the coolant inlet 31 and coolant outlet 33, respectively.

[0055] In this application, terms such as “upper,” “lower,” “upper,” and “downward” are intended to be used descriptively in reference to and in relation to the orientation shown in the figures for clarity; however, the embodiments implemented and included in the claims may also include examples in which the systems and apparatus are in different orientations.

[0056] While specific applications of the present technology have been illustrated and discussed above, the disclosed technology can be used in a variety of environments according to many examples of the present technology. The above discussion does not imply that the disclosed technology is suitable only for embodiments within the environments shown and described above. As should be understood, the various embodiments described with respect to the figures of this specification are not intended to limit the present technology to any particular embodiment described. Accordingly, the present technology can be carried out using additional configurations without departing from the methods and systems disclosed herein, and / or some of the embodiments described may be excluded.

[0057] While this disclosure describes several aspects of the Art with reference to the accompanying drawings, the drawings show only a portion of the possible embodiments. However, other embodiments can be carried out in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided to ensure that this disclosure is thorough and complete and to adequately convey the scope of possible embodiments to those skilled in the art.

[0058] Similarly, where process operations are disclosed, those operations are described for illustrative purposes of the Art and are not intended to limit the disclosure to any particular sequence of operations. For example, operations may be performed in a different order, two or more operations may be performed simultaneously, additional operations may be performed, or disclosed operations may be excluded without departing from the disclosure. Furthermore, each operation may be achieved through one or more suboperations. The disclosed processes are repeatable.

[0059] While specific embodiments have been described herein, the scope of this art is not limited to those specific embodiments. Those skilled in the art will recognize other embodiments or improvements that fall within the scope of this art. Accordingly, specific structures, functions, or operations are disclosed only as exemplary embodiments. The scope of this art is defined by the following claims and equivalents.

Claims

1. An exhaust gas recirculation system for an internal combustion engine, wherein the exhaust gas recirculation system is An electric motor located inside the electric motor housing, An exhaust gas recirculation pump coupled to the electric motor, the exhaust gas recirculation pump including a pump housing that defines the internal volume, A plurality of rotors arranged within the aforementioned internal volume, wherein a first rotor among the plurality of rotors is connected to the electric motor, A transmission assembly comprising a drive gear mounted on the first rotor, wherein the transmission assembly comprises a driven gear meshing with the drive gear, the driven gear being coupled to a second rotor among the plurality of rotors, and the transmission assembly is positioned on the opposite side of the pump housing from the electric motor, A lip seal positioned around a rotor shaft and in contact with the rotor shaft, wherein the rotor shaft is integral with either the first rotor or the second rotor, and the lip seal and A pair of piston ring seals arranged around the rotor shaft and in contact around the rotor shaft, wherein the lip seal is located between a first set of bearings and the pair of piston ring seals, and the first set of bearings is located between the gear and the lip seal, the pair of piston ring seals Exhaust gas recirculation system.

2. The exhaust gas recirculation system according to claim 1, further comprising a coolant passage at least partially defined by the pump housing, wherein the coolant passage is defined around at least a second set of bearings.

3. The exhaust gas recirculation system according to claim 2, wherein the pump housing defines a fin structure within the coolant flow path.

4. The exhaust gas recirculation system according to claim 3, wherein the fin structure is formed radially around the second set of bearings.

5. Motor mounting adapter and The motor mounting adapter has a coolant inlet and The motor mounting adapter further includes a coolant outlet formed in the motor mounting adapter, The exhaust gas recirculation system according to claim 2, wherein the coolant inlet and the coolant outlet are configured to introduce coolant and to define at least partially the flow path of the coolant.

6. The exhaust gas recirculation system according to claim 1, further comprising a bearing plate attached to the pump housing, the bearing plate including a journal formed to receive the first set of bearings.

7. The exhaust gas recirculation system according to claim 6, wherein the bearing plate and the outer cover attached to the bearing plate define an oil cavity.

8. The exhaust gas recirculation system according to claim 7, wherein the transmission assembly is located within the oil cavity.

9. The exhaust gas recirculation system according to claim 7, wherein the bearing plate includes at least one oil inlet extending to at least one oil outlet, the at least one oil outlet being defined by the outer cover, and the oil lubricates a second set of bearings and the transmission assembly.

10. The exhaust gas recirculation system according to claim 9, wherein the oil outlet is arranged to allow oil to be discharged from the oil cavity by gravity.

11. The shelf defined by the pump housing, A pocket defined by at least the shelf, the second bearing assembly, the motor mounting adapter, and the electric motor shaft, The exhaust gas recirculation system according to claim 1, further comprising a biasing element disposed within the pocket and surrounding the electric motor shaft.

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