Patent Description:
Some vehicles include a charging device, such as a turbocharger or supercharger, that boosts engine performance by compressing air that is then fed to the engine. These devices may also be employed in fuel cell systems or other systems. In some cases, an e-charger may be provided. The e-charger may include an electric motor that is configured to drive and rotate a compressor wheel for compressing an airflow, which is then fed to an engine, a fuel cell stack, etc..

These charging devices may include a cooling system. In the case of an e-charger, for example, a cooling system may be provided that directs flow of a coolant through the device to maintain operating temperatures within a predetermined range. The electric motor may be cooled, for example, to improve operating efficiency of the motor.

However, conventional cooling systems for e-chargers suffer from various deficiencies, and operating efficiency may be negatively affected as a result. It may be difficult to provide an acceptable cooling effect for some charging devices and/or under certain operating conditions. There may be space constraints that limit the size and/or routing of the cooling circuit and, thus, negatively affects cooling performance.

Thus, it is desirable to provide a cooling system for an e-charger that improves the cooling effect. It is also desirable to provide an e-charger cooling system that is compact, highly manufacturable, and that is cost effective. Other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background discussion. Document <CIT> relates to a similar machine.

The present invention discloses an e-charger as defined in claim <NUM> and a method of manufacturing an e-charger as defined in claim <NUM>.

The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:.

The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

Broadly, example embodiments disclosed herein include an improved e-charger. The disclosed e-charger may be a device with a motor that drives a compressor wheel for providing a compressed airstream to a downstream component (e.g., to a fuel cell stack, to an internal combustion engine, etc.). Also, the e-charger of the present disclosure may be configured as an electric supercharger, a hybrid turbocharger, an e-boost device, an e-turbo device, an e-assist charging device, or other related component.

In particular, an e-charger and methods of manufacturing the same are disclosed, wherein the e-charger also includes a fluid system for a coolant (i.e., "a cooling system"). The cooling system may include a plurality of passages that may collectively define a cooling jacket that surrounds a majority of the motor. The passages may also be fluidly connected (e.g., in-series) from an inlet to an outlet.

In some embodiments, the inlet and the outlet may be provided proximate one end of the motor. Also, in some embodiments, at least some of the passages may extend longitudinally toward the opposite end of the motor and other passages may extend back longitudinally toward the first end. There may also be at least one passage fluidly connecting two longitudinal passages, and in some embodiments, this connecting passage may extend along an end of the motor.

Furthermore, in some embodiments, the cooling system may include distinct longitudinal passages that provide flow back-and-forth longitudinally between the ends of the motor. Also, end passages may fluidly connect different pairs of the longitudinal passages. These passages may provide cooling to the motor, to one or more bearings, and/or to other components of the e-charger.

The disclosed e-charger may provide various advantages. For example, the layout and construction of the cooling system may be relatively simple and compact and, yet, may provide effective cooling for the motor, bearings, electronics, and/or other components. Also, flow through the cooling system may result in relatively low pressure loss. Also, the coolant may flow along a labyrinthine path at a relatively high Reynolds number, resulting in high cooling capacity. The cooling system provides high cooling efficiency and maintains the motor, bearing, and/or other components within acceptable operating temperatures for a long operating lifetime. The e-charger may operate at high efficiency in a wide variety of operating conditions as a result. Moreover, the e-charger may have high manufacturability due to the features of the present disclosure.

<FIG> is a schematic view of an example e-charger <NUM> according to example embodiments of the present disclosure. It will be appreciated that the term "e-charger" as used herein will be understood broadly by those in the art, for example, to include devices with an electrically driven compressor wheel regardless of where the e-charger <NUM> is incorporated, the type of system in which the e-charger <NUM> is incorporated, etc. It will also be appreciated that the e-charger <NUM> of the present disclosure may also be referred to as an electrically driven compressor assembly. Also, the e-charger <NUM> of the present disclosure may be operatively attached to an exhaust-driven turbine wheel, for example, in a hybrid turbocharger or e-assist turbocharger. The e-charger <NUM> may also be configured as an electric supercharger, as an e-boost device, e-turbo, or other related component. Also, the e-charger <NUM> may be fluidly and otherwise operatively coupled to additional charging devices, either upstream or downstream of the e-charger <NUM>.

As shown, the e-charger <NUM> may be incorporated within a fuel cell system <NUM>. Also, as shown, the e-charger <NUM> may be configured as an electric compressor device (i.e., electric supercharger) with a single-stage compressor.

Generally, the e-charger <NUM> may include a motor section <NUM> with a first end <NUM> and a second end <NUM>. The e-charger <NUM> may also include a compressor section <NUM>. The motor section <NUM> may drive a rotating group <NUM> of the e-charger <NUM> about an axis <NUM> relative to a housing <NUM> of the e-charger <NUM>, thereby providing a compressed airstream (represented by arrow <NUM>) to a fuel cell stack <NUM> of the fuel cell system <NUM>.

It will be appreciated that the e-charger <NUM> and/or features of the present disclosure may be configured differently than the illustration. Also, it will be appreciated that the e-charger <NUM> may be incorporated within a system other than a fuel cell system. For example, the e-charger <NUM> may be configured for supplying the compressed airstream <NUM> to an internal combustion engine, to another charging device, etc..

The motor section <NUM> of the e-charger <NUM> may include an electric motor <NUM> with a stator <NUM> and a rotor <NUM> (<FIG>, <FIG>, and <FIG>), which are centered on the axis <NUM>. The rotor <NUM> may be fixed to a shaft <NUM> for rotation as a unit about the axis <NUM>. The shaft <NUM> may project from the rotor <NUM> and away from the first end <NUM> of the motor section <NUM>. Furthermore, the motor section <NUM> may include one or more parts of the housing <NUM>. For example, the housing <NUM> may include a motor housing <NUM>, which houses, encapsulates, and/or surrounds the stator <NUM> and at least part of the rotor <NUM> in the motor section <NUM>.

The compressor section <NUM> may include a compressor wheel <NUM>, which may be mounted on the shaft <NUM> at the first end <NUM> of the motor section <NUM>. The compressor wheel <NUM> may be fixed to the rotor <NUM> via the shaft <NUM> to rotate as a unit with the rotating group <NUM> of the e-charger <NUM>. The compressor wheel <NUM> may be fixed to the shaft <NUM> via one or more fasteners, weldments, and/or other attachment. The compressor section <NUM> may also include one or more parts of the housing <NUM>. The compressor section <NUM> may include a compressor housing member <NUM> (shown in phantom in <FIG>). The compressor housing member <NUM> may be fixed to a side of the motor housing <NUM> (e.g., by fasteners, weldments, or other attachments). The compressor housing member <NUM> may include a volute structure with an axial inlet <NUM> and an outlet <NUM>. The compressor housing member <NUM> may be a unitary, one-piece compressor housing member <NUM>. The axial inlet <NUM> may be tubular, straight, and centered on the axis <NUM>. The outlet <NUM> may be directed outward and tangential to a circle that is centered on the axis <NUM>.

The motor <NUM> may drivingly rotate the compressor wheel <NUM> within the compressor housing member <NUM> about the axis <NUM>. An inlet airstream (represented by arrow <NUM> in <FIG>) may flow into the inlet <NUM> and flow through the compressor housing <NUM>. A resultant compressed airstream (represented by arrow <NUM>) may be directed from the outlet <NUM>. In some embodiments, the compressed airstream <NUM> may be cooled by an intercooler <NUM> and may flow to the fuel cell stack <NUM> for boosting the operating efficiency of the fuel cell system <NUM>.

The fuel cell stack <NUM> (<FIG>) may contain a plurality of fuel cells. Hydrogen may be supplied to the fuel cell stack <NUM> from a tank <NUM>, and oxygen may be supplied to the fuel cell stack <NUM> to generate electricity by a known chemical reaction. The fuel cell stack <NUM> may generate electricity for an additional electric motor <NUM> and/or other connected electrical devices. The fuel cell system <NUM> may be included in a vehicle, such as a car, truck, sport utility vehicle, van, motorcycle, aircraft, etc. Accordingly, in some embodiments, the electric motor <NUM> may convert the electrical power generated by the fuel cell stack <NUM> to mechanical power to drive and rotate an axle (and, thus, one or more wheels) of the vehicle. In some embodiments, the fuel cell stack <NUM> may provide electricity for the stator <NUM> to drivingly rotate the rotor <NUM> and other components of the rotating group <NUM> of the e-charger <NUM>. However, it will be appreciated that the fuel cell system <NUM> may be configured for a different use without departing from the scope of the present disclosure.

Furthermore, an exhaust gas stream (represented by arrow <NUM>) from the fuel cell stack <NUM> may be exhausted to atmosphere as represented in <FIG>. Stated differently, the exhaust gas stream <NUM> may be directed away from the e-charger <NUM>. In other embodiments, the exhaust gas stream <NUM> may be directed back toward the e-charger <NUM>, for example, to drive rotation of a turbine wheel that is included in the rotating group <NUM>. This may, in turn, drive rotation of the compressor wheel <NUM>, for example, to assist the electric motor <NUM>.

The e-charger <NUM> and/or other components of the fuel cell system <NUM> may be controlled by a controller <NUM> (<FIG>). The controller <NUM> may be a computerized system with a processor, various sensors, and other components for electrically controlling operation of the motor <NUM>, the fuel cell stack <NUM>, and/or other features of the system <NUM>. In some embodiments, the controller <NUM> may define or may be part of the electrical control unit (ECU) of a vehicle.

Accordingly, the controller <NUM> may generate control commands for turning the motor <NUM> of the e-charger <NUM> ON and OFF and/or for changing the speed of the motor <NUM>. The controller <NUM> may generate these control commands based on input from sensors. Thus, the speed of the motor <NUM> (and, thus, the rotational speed of the compressor wheel <NUM>) may be controlled, for example, based on a sensed throttle position or other sensed characteristic of the system.

Furthermore, the e-charger <NUM> may include a cooling system, which is indicated generally at <NUM> in the Figures, and which will be discussed in detail below according to example embodiments. The cooling system <NUM> may include an inlet <NUM>, an outlet <NUM> and a plurality of passages <NUM> (<FIG>) defined through the housing <NUM> for conducting a flow of coolant (e.g., liquid coolant) from the inlet <NUM> to the outlet <NUM>. The cooling system <NUM> may define a cooling jacket that surrounds a majority of the motor <NUM>. As will be discussed, the cooling system <NUM> may be routed through the housing <NUM> to provide effective cooling while also ensuring that the e-charger <NUM> is compact and relatively lightweight. Additionally, the cooling system <NUM> provides various manufacturing advantages as will be discussed.

Referring to <FIG> and <FIG>, the motor housing <NUM> of the e-charger <NUM> will now be discussed in greater detail according to example embodiments. The motor housing <NUM> may include an outer housing <NUM> (<FIG>) with an outer body <NUM> (<FIG> and <FIG>) (i.e., outer structure, outer member, etc.). The outer body <NUM> may be block-shaped with a variety of rigid, strong, supportive structures made, for example, from metal. The outer body <NUM> may include a receptacle <NUM> (<FIG>). The receptacle <NUM> may be generally barrel-shaped, cylindrical, etc. The receptacle <NUM> may be centered on the axis <NUM> and recessed along the axis <NUM> from the first end <NUM> of the motor section <NUM> toward the second end <NUM>. The receptacle <NUM> may be open at the first end <NUM> and closed off at the second end <NUM> by an end plate <NUM> (<FIG>) of the outer body <NUM>. As shown in <FIG>, the receptacle <NUM> may include a circular rim <NUM>. The receptacle <NUM> may also include an inner diameter surface <NUM> with one or more projections 168a, 168b, 168c, 168d (<FIG> and <FIG>).

The projections 168a-168d may be elongate rails that project radially inward toward the axis <NUM>. The projections 168a-168d may extend longitudinally along the axis <NUM> (e.g., substantially parallel to the axis <NUM>) from the first end <NUM> to the second end <NUM> of the motor section <NUM>. The projections 168a-168d may be spaced substantially equally about the axis <NUM>. As shown, there may be four projections 168a-168d, which are spaced apart by ninety degrees (<NUM>°) from neighboring ones of the projections 168a-168d with respect to the axis <NUM>. Each projection 168a-168d may include a respective inward-facing nest surface 169a, 169b, 169c, 169d. The nest surfaces 169a-169d may be substantially smooth and may be arcuately curved about the axis <NUM>. The nest surfaces 169a-169d may also extend longitudinally along (e.g., parallel to) the axis <NUM> between the first end <NUM> and the second end <NUM>.

Also, the inner diameter surface <NUM> of the receptacle <NUM> may include intermediate surfaces 170a, 170b, 170c, 170d, which are each defined circumferentially between neighboring pairs of the nest surfaces 169a-169d. For example, as shown in <FIG>, the intermediate surface 170a may be defined between the nest surface 169a and the nest surface 169d. The intermediate surface 170b may be defined between the nest surface 169a and the nest surface 169b. The intermediate surface 170c may be defined between the nest surface 169b and the nest surface 169c. The intermediate surface 170d may be defined between the nest surface 169c and the nest surface 169d. Generally, the intermediate surfaces 170a-170d may contour arcuately about the axis <NUM> and may extend longitudinally along the axis <NUM> from the first end <NUM> to the second end <NUM> of the motor section <NUM>. The intermediate surfaces 170a-170d may also include various contoured surfaces that define the transitions to respective ones of the nest surfaces 169a-169d.

Furthermore, the outer body <NUM> may include the end plate <NUM>. The end plate <NUM> may be a relatively flat panel that is arranged normal to the axis <NUM> and that defines a majority of the second end <NUM> of the motor section <NUM>. As shown in <FIG>, the end plate <NUM> may include an inner surface <NUM> that faces inwardly along the axis <NUM> and that defines the closed longitudinal end of the receptacle <NUM>, proximate the second end <NUM>. The inner surface <NUM> may include one or more recesses <NUM>. For example, there may be two arcuate recesses <NUM> arranged on opposite sides of the axis <NUM>. Furthermore, there may be an opening <NUM> for receiving electrical connectors <NUM> of the motor <NUM>. In addition, the inner surface <NUM> may include a bearing mount <NUM>. The bearing mount <NUM> may be a hollow, cylindrical projection that is centered on the axis <NUM>. The bearing mount <NUM> may be integrally connected to the other portions of the end plate <NUM> and may project inwardly along the axis <NUM> partially into the receptacle <NUM>.

The outer body <NUM> may further include one or more electrical connector structures <NUM> that project substantially radially outward. The electrical connector structures <NUM> may support one or more electrical connectors that provide electrical communication with the controller <NUM>.

The outer housing <NUM> may further include an end plate <NUM> (i.e., an end member). The end plate <NUM> may be round, thin and disposed transverse (e.g., substantially perpendicular) to the axis <NUM>. The end plate <NUM> may be removably attached to the outer body <NUM> at the first end <NUM> of the motor section <NUM> to cover over and close off the receptacle <NUM>. The end plate <NUM> may be removably attached and fixed to the outer body <NUM> via fasteners in some embodiments. The end plate <NUM> may include an inner surface <NUM> (<FIG>) that faces inward into the receptacle <NUM>. The inner surface <NUM> may include a bearing mount <NUM>, which is hollow, cylindrical, and centered on the axis <NUM>. The bearing mount <NUM> may project along the axis <NUM> partially into the receptacle <NUM>. The inner surface <NUM> may also include a plurality of projections 215a, 215b, 215c, 215d that are elongate and that project radially outward from the bearing mount <NUM> to the outer diameter of the end plate <NUM>. There may be four projections 215a, 215b, 215c, 215d in some embodiments, and they may be spaced substantially equally about the axis <NUM> (e.g., spaced apart by ninety degrees (<NUM>°)). The end plate <NUM> may further include a central aperture <NUM>. The shaft <NUM> may pass through the end plate <NUM> via the central aperture <NUM>. The compressor wheel <NUM> may be fixed to the shaft <NUM> to be disposed at an outer surface <NUM> of the end plate <NUM>.

The e-charger <NUM> may additionally include one or more dampeners <NUM> (<FIG>). The dampener <NUM> may be shaped as a continuous band with wavy or otherwise uneven surfaces on its inner and/or outer radially-facing surfaces. The dampener <NUM> may have a thickness measured between these opposite radially-facing surfaces, and this thickness may remain substantially continuous along the dampener <NUM>. The dampener <NUM> may be made of an elastomeric material, a resilient metal material, or otherwise. The dampener <NUM> may be received within the bearing mount <NUM>. The dampener <NUM> may resiliently deflect in the due to vibrations and/or other forces during operation. The dampener <NUM> may resiliently recover to the neutral shape shown in <FIG> (i.e., the dampener <NUM> may be biased toward the neutral position) to counterbalance and/or dampen the vibrations or other forces.

The e-charger <NUM> may further include one or more bearings 214a, 214b. The bearing(s) 214a, 214b may support the shaft <NUM> for rotation about the axis <NUM>. In some embodiments, there may be two bearings 214a, 214b, and both may be a roller-type bearing. One bearing 214a may be disposed proximate the first end <NUM> and may include an outer member (e.g., an outer race) that is fixed within the bearing mount <NUM> of the end plate <NUM>, an inner member (e.g., an inner race) that is fixed to the shaft <NUM>, and a plurality of roller elements that are disposed between the outer member and the inner member for supporting rotation of the shaft <NUM>. The other bearing 214b may be disposed proximate the second end <NUM> and may include an outer member fixed within the bearing mount <NUM> of the end plate <NUM>, an inner member fixed to the shaft <NUM>, and roller elements disposed therebetween.

The motor housing <NUM> may further include a motor case <NUM>. The motor case <NUM> may encase the motor <NUM>, and the motor case <NUM> may be received within the receptacle <NUM> of the outer body <NUM>. The motor case <NUM> may be substantially cylindrical and hollow. The exterior of the motor case <NUM> may include a first longitudinal end face <NUM>, an outer diameter surface <NUM>, and a second longitudinal end face <NUM>. The outer diameter surface <NUM> may extend circumferentially about the axis <NUM> and may extend longitudinally between the first and second longitudinal end faces <NUM>, <NUM>. The outer diameter surface <NUM> may be centered with respect to the axis <NUM>. A majority of the outer diameter surface <NUM> may be substantially smooth and continuous about the axis <NUM>. The first and second longitudinal end faces <NUM>, <NUM> may be disposed on opposite ends of the outer diameter surface <NUM> with the first longitudinal end face <NUM> proximate the first end <NUM> of the motor section <NUM> and the second longitudinal end face <NUM> proximate the second end <NUM>. The first and second longitudinal end faces <NUM>, <NUM> may be annular and may be disposed substantially perpendicular to the axis <NUM>.

The first longitudinal end face <NUM> may include a plurality of rail-like projections 221a, 221b, 221c, 221d (<FIG>) that project along the axis <NUM> toward the first end <NUM>. Each projection 221a-221d may extend radially from a central opening <NUM> to the outer diameter of the end face <NUM>. In some embodiments, there may be four projections 221a-221d that are spaced apart equally about the axis <NUM> (e.g., spaced apart by ninety degrees (<NUM>°)). The inner ends of the projections 221a-221d may also be flush with an annular projection <NUM> that encircles the central opening <NUM>. The second longitudinal end face <NUM> may include a projection <NUM> (<FIG>) that projects along the axis <NUM> toward the second end <NUM> from surrounding areas of the face <NUM>. A portion of the projection <NUM> may extend about the connectors <NUM> and about a central opening <NUM> of the end face <NUM>. Another portion of the projection <NUM> may be rail-shaped and may extend in the radial direction away from the central opening <NUM> to the outer diameter of the end face <NUM>.

The rotor <NUM> and the stator <NUM> may be disposed longitudinally between the first and second longitudinal end faces <NUM>, <NUM>, and the outer diameter surface <NUM> may continuously surround and cover over the stator <NUM>. The shaft <NUM> may extend through the central openings <NUM>, <NUM> to connect to the bearings 214a, 214b.

In some embodiments, the motor case <NUM> may be formed via a casting process and may be formed of metal. Also, as shown in <FIG>, the motor case <NUM> may be a multi-part shell conforming in shape to the stator <NUM>. For example, a first member <NUM> of the motor case <NUM> may define the first longitudinal end face <NUM>, and a second member <NUM> of the motor case <NUM> may define the second longitudinal end face <NUM> and a majority of the outer diameter surface <NUM>. Thus, in some embodiments, the second member <NUM> may be a hollow cylindrical structure with an open end that is closed off and covered by the first member <NUM>. Also, as shown in <FIG>, the first member <NUM> may receive an upper rim portion <NUM> of the second member <NUM> and may be fixedly attached thereto. A first seal member <NUM> may be included for creating a substantially hermetic seal between the first and second members <NUM>, <NUM>. The first seal member <NUM> may be an O-ring that is received in an outer diameter groove of the second member <NUM> and that seals against a substantially smooth opposing surface of the first member.

The motor case <NUM> and the motor <NUM> therein may be received within the outer housing <NUM>. Specifically, the motor case <NUM> may be received within the receptacle <NUM> of the outer body <NUM>, and the end plate <NUM> may be fixed to the rim <NUM> (i.e., the end plate <NUM> and outer body <NUM> cooperatively house the motor case <NUM> and the motor <NUM> therein). The motor case <NUM> may be received in the receptacle <NUM> with the second longitudinal end face <NUM> facing (opposing) the inner surface <NUM> of the end plate <NUM>. Also, the outer diameter surface <NUM> may oppose the inner diameter surface <NUM> of the outer housing <NUM>. Furthermore, with the end plate <NUM> installed on the outer housing <NUM>, the first longitudinal end face <NUM> may oppose the inner surface <NUM>. As shown in <FIG> and <FIG>, a second seal member <NUM> may be included between the second longitudinal end face <NUM> and the inner surface <NUM> of the end plate <NUM>. As shown in <FIG>, the second seal member <NUM> may extend along at least part of the projection <NUM>. The second seal member <NUM> may be made from an elastomeric material and may include a first portion <NUM> that extends about the connectors <NUM> and the central opening <NUM> and a second portion <NUM> that extends along both radially-extending edges of the projection <NUM>. The second seal member <NUM> may substantially hermetically seal against the opposing inner surface <NUM>. Additionally, there may one or more features (i.e., anti-rotation features) that retain the motor case <NUM> against rotation about the axis <NUM> relative to the outer housing <NUM>.

As mentioned above, the e-charger <NUM> may include the cooling system <NUM> (i.e., coolant jacket, cooling circuit, etc.). The cooling system <NUM> may include a plurality of fluid channels, reservoirs, passages, circuits, etc. that receive one or more flows of liquid coolant. The coolant may flow through the cooling system <NUM> and remove heat from the e-charger <NUM> to maintain high operating efficiency. The cooling system <NUM> and flow therethrough is illustrated schematically in <FIG> and <FIG>. The cooling system <NUM> may extend through the motor housing <NUM>, and a majority of the cooling system <NUM> may be cooperatively defined by (and defined between) the outer housing <NUM> and the motor case <NUM>. The plurality of fluid passages <NUM> of the cooling system <NUM> may be connected in-series in some embodiments from the inlet <NUM> to the outlet <NUM>. Fluid coolant may pass from the inlet <NUM>, through the passages <NUM>, and out via the outlet <NUM>, and heat may transfer to the coolant and out of the e-charger <NUM> to maintain operations within a predetermined temperature range. For example, heat from the motor <NUM>, the bearings 214a, 214b, and/or the housing <NUM> may transfer to the coolant to be carried away from the e-charger <NUM>.

In some embodiments, different ones of the plurality of passages <NUM> may be separated by one or more fluid boundaries <NUM> (i.e., dams, barriers, fluid retainers, etc.) as will be discussed, the motor case <NUM> may include a projection that partly defines the fluid boundary member, and the outer housing <NUM> may include a surface that nests with the projection. The surfaces may nest to cooperatively define the respective fluid boundary <NUM>. The surfaces may "nest" in a variety of ways without departing from the scope of the present disclosure. For example, the surfaces may be flat and planar but closely adjacent to nest together. Also, in some embodiments, the surfaces may have corresponding contours, shapes, etc. One nesting surface may be concave while the other may be convex and may have corresponding radii in some embodiments. These surfaces may or may not come into abutting contact.

As shown in <FIG>, <FIG>, <FIG>, and <FIG>, the inlet <NUM> and the outlet <NUM> may both be disposed proximate the first end <NUM>. Also, in some embodiments, the inlet <NUM> and the outlet <NUM> may be substantially parallel (i.e., the axes of the inlet <NUM> and outlet <NUM> may be straight and substantially parallel). Furthermore, the inlet <NUM> and the outlet <NUM> may be disposed on a common side of the axis <NUM> as shown. The inlet <NUM> and the outlet <NUM> may extend radially through the end plate <NUM>. With the inlet <NUM> and outlet <NUM> in this arrangement, the e-charger <NUM> may be compact and coolant lines to/from the e-charger <NUM> may be incorporated and attached easily to the fuel cell system <NUM>.

The plurality of passages <NUM> (<FIG>) may define a single, continuous fluid path from the inlet <NUM> to the outlet <NUM>. The passages <NUM> and the fluid flow path through the cooling system <NUM> is illustrated in <FIG> and <FIG>. For purposes of clarity, only the voids defined between the outer housing <NUM> and the motor case <NUM> are shown in <FIG> and <FIG>. Some of the fluid boundaries <NUM> are indicated in <FIG> and <FIG> with cross hatching for clarity to distinguish from the passages <NUM>.

In some embodiments, the plurality of passages <NUM> may include at least one longitudinal passage, which extend generally along the axis <NUM> between the first end <NUM> and the second end <NUM>. For example, there may be at least four such longitudinal passages. In the illustrated embodiments, for example, the e-charger <NUM> may include a first longitudinal passage <NUM>, a second longitudinal passage <NUM>, a third longitudinal passage <NUM>, and a fourth longitudinal passage <NUM>. At least one of these longitudinal passages may extend substantially parallel to the axis <NUM> and may direct the coolant in either a first direction along the axis (from the first end <NUM> to the second end <NUM>) or in a second direction (from the second end <NUM> to the first end <NUM>).

Also, the plurality of passages <NUM> may include at least one transverse passage, which extend transverse to the axis <NUM> (generally radially and/or arcuately about the axis). According to the invention the transverse passage(s) provides flow in the radial and circumferential direction with respect to the axis <NUM>. Also, the transverse passage may be disposed proximate the first end <NUM> or the second end <NUM>. For example, the e-charger <NUM> may include a first end receiving passage <NUM> (a first transverse passage). As shown in the illustrated embodiments of <FIG> and <FIG>, the inlet <NUM> may be fluidly connected to the first receiving passage <NUM>. Other transverse passages may be included, such as a second end connecting passages <NUM>, <NUM>, a first end connecting passage <NUM>, and a first end discharge passage <NUM>.

The first end receiving passage <NUM> may be defined at the first end <NUM> between the end plate <NUM> and the first longitudinal end face <NUM> of the motor case <NUM>. The projections 215a, 215d and bearing mount <NUM> of the end plate <NUM> may nest, respectively, against the projections 221a, 215d, <NUM> of the motor case <NUM> to cooperatively define a wall, dam, or other fluid boundary <NUM> for directing flow of the coolant. These opposing surfaces of the end plate <NUM> and the motor case <NUM> may be closely adjacent and, in some embodiments, may abut and/or seal together. However, this is not mandatory, and some amount of permitted leakage may occur across the nesting surfaces while the boundary <NUM> contains a majority of the coolant within the passage <NUM>.

As shown, the first end receiving passage <NUM> may be confined to a first quadrant of the e-charger <NUM> with respect to the axis <NUM> at the first end <NUM> of the e-charger <NUM>. Flow into the first end receiving passage <NUM> may be received from the inlet <NUM> radially, and redirected transversely and arcuately about the axis <NUM>, for example, to provide cooling to the bearing 214a. Flow from the first end receiving passage <NUM> may also be redirected toward the first longitudinal passage <NUM>. This flow within and through the first end receiving passage <NUM> is illustrated generally by arrow <NUM> in <FIG>.

The first longitudinal passage <NUM> may be defined between the outer diameter surface <NUM> of the motor case <NUM> and the inner diameter surface <NUM> of the outer body <NUM>. More specifically, the passage <NUM> may be defined between the intermediate surface 170a and the outer diameter surface <NUM> as shown in <FIG>. The first longitudinal passage <NUM> may be fluidly connected to the first end receiving passage <NUM> and may receive flow therefrom. The nest surface 169a may nest with the surface <NUM> of the motor case <NUM>, and the nest surface 169d may nest with the surface <NUM> to define the respective fluid boundaries <NUM>. As shown in <FIG>, the first longitudinal passage <NUM> may be arcuate with respect to the axis <NUM>. The first longitudinal passage <NUM> may extend arcuately within the first quadrant of the axis <NUM> (along with the first end receiving passage <NUM>), and the first longitudinal passage <NUM> may pass longitudinally from the first end <NUM> to the second end <NUM> as indicated by arrow <NUM>. The axis of the passage <NUM> may be parallel to the axis <NUM> in some embodiments. Coolant flow from the first end receiving passage <NUM> may be received and directed longitudinally along the axis <NUM> for cooling the motor <NUM>.

Furthermore, as shown in <FIG>, the cooling system <NUM> may include the second end connecting passage <NUM>. The second end connecting passage <NUM> may be defined at the second end <NUM> between the end plate <NUM> and the second longitudinal end face <NUM> of the motor case <NUM>. The first portion <NUM> and the second portion <NUM> of the projection <NUM> may nest against the inner surface <NUM> of the end plate <NUM> to define the second end connecting passage <NUM> for cooperatively defining a respective fluid boundary <NUM>. As shown, the fluid boundaries <NUM> may define the second end connecting passage <NUM> across the first quadrant and circumferentially to a second quadrant with respect to the axis <NUM> at the second end <NUM> of the e-charger <NUM>. Flow from the first longitudinal passage <NUM> may be received by the second end connecting passage <NUM> and may flow arcuately about the axis <NUM>, for example, to provide cooling to the bearing 214b. Flow from the second end connecting passage <NUM> may also be redirected toward the second longitudinal passage <NUM> of the cooling system <NUM>. This flow is illustrated generally by arrow <NUM> in <FIG>.

The second longitudinal passage <NUM> may be defined between the outer diameter surface <NUM> of the motor case <NUM> and the inner diameter surface <NUM> of the outer body <NUM>. More specifically, the passage <NUM> may be defined between the intermediate surface 170d and the outer diameter surface <NUM> as shown in <FIG>. The second longitudinal passage <NUM> may be fluidly connected to the second end connecting passage <NUM> and may receive flow therefrom. The nest surface 169d may nest, abut, and substantially conform to the surface <NUM> of the motor case <NUM>, and the nest surface 169c may nest, abut, and substantially conform to the surface <NUM> of the motor case <NUM> to define the respective fluid boundary <NUM>. As shown in <FIG>, the second longitudinal passage <NUM> may be arcuate with respect to the axis <NUM>. The second longitudinal passage <NUM> may extend arcuately within the second quadrant of the axis <NUM> (along with the second end connecting passage <NUM>), and the second longitudinal passage <NUM> may pass longitudinally from the second end <NUM> to the first end <NUM> as indicated by arrow <NUM>. The axis of the passage <NUM> may be parallel to the axis <NUM> in some embodiments. Coolant flow from the second end connecting passage <NUM> may be received by the second longitudinal passage <NUM> and directed longitudinally along the axis <NUM> from the second end <NUM> toward the first end <NUM> for cooling the motor <NUM>. Flow from the second longitudinal passage <NUM> may be received in the first end connecting passage <NUM> (<FIG>).

The first end connecting passage <NUM> may be defined at the first end <NUM> between the end plate <NUM> and the first longitudinal end face <NUM> of the motor case <NUM>. The projections 215b, 215d and bearing mount <NUM> of the end plate <NUM> may nest, respectively, against the projections 221b, 221d, <NUM> of the motor case <NUM> to cooperatively define the respective fluid boundary <NUM>. Also, the projection 215c may be spaced apart from the projection 221c in the longitudinal direction to define a gap that allows passage of the fluid from the second quadrant to a third quadrant of the e-charger <NUM>. This flow path is indicated by arrow <NUM> in <FIG>. This flow may allow the coolant in the first end connecting passage <NUM> to remove heat from the bearing 214a and/or the motor <NUM>. Flow from the first end connecting passage <NUM> may be received in the third longitudinal passage <NUM>.

The third longitudinal passage <NUM> may be defined between the outer diameter surface <NUM> of the motor case <NUM> and the inner diameter surface <NUM> of the outer body <NUM>. More specifically, the passage <NUM> may be defined between the intermediate surface 170c and the outer diameter surface <NUM> as shown in <FIG>. The nest surface 169c may nest, abut, and/or substantially conform to the surface <NUM> of the motor case <NUM>, and the nest surface 169b may nest, abut, and/or substantially conform to the surface <NUM> of the motor case <NUM> to define respective boundaries <NUM>. As shown in <FIG>, the third longitudinal passage <NUM> may be arcuate with respect to the axis <NUM>. The third longitudinal passage <NUM> may extend arcuately within the third quadrant of the axis <NUM>, and the third longitudinal passage <NUM> may pass longitudinally from the first end <NUM> to the second end <NUM> as indicated by arrow <NUM>. The axis of the passage <NUM> may be parallel to the axis <NUM> in some embodiments. Coolant flow from the first end connecting passage <NUM> may be received by the third longitudinal passage <NUM> and directed longitudinally along the axis <NUM> from the first end <NUM> to the second end <NUM> for cooling the motor <NUM>. Flow from the third longitudinal passage <NUM> may be received in the second end connecting passage <NUM> (<FIG>).

The second end connecting passage <NUM> may be defined at the second end <NUM> between the end plate <NUM> and the second longitudinal end face <NUM> of the motor case <NUM>. The first portion <NUM> and the second portion <NUM> of the projection <NUM> may nest against the inner surface <NUM> of the end plate <NUM> to define the second end connecting passage <NUM> for cooperatively defining the fluid boundary <NUM>. As shown, the second end connecting passage <NUM> may be confined to the third quadrant and a fourth quadrant of the e-charger <NUM>. Flow from the third longitudinal passage <NUM> may be received by the second end connecting passage <NUM> and may flow arcuately about the axis <NUM>, for example, to provide cooling to the bearing 214b. Flow from the second end connecting passage <NUM> may also be redirected to the fourth longitudinal passage <NUM> of the cooling system <NUM>. This flow is illustrated generally by arrow <NUM> in <FIG>.

The fourth longitudinal passage <NUM> may be defined between the outer diameter surface <NUM> of the motor case <NUM> and the inner diameter surface <NUM> of the outer body <NUM>. More specifically, the passage <NUM> may be defined between the intermediate surface 170b and the outer diameter surface <NUM> as shown in <FIG>. The nest surface 169b may nest, abut, and/or substantially conform to the surface <NUM> of the motor case <NUM>, and the nest surface 169a may nest, abut, and/or substantially conform to the surface <NUM> of the motor case <NUM> to define respective boundaries <NUM> of the fourth longitudinal passage <NUM>. As shown in <FIG>, the fourth longitudinal passage <NUM> may be arcuate with respect to the axis <NUM>. The fourth longitudinal passage <NUM> may extend arcuately within the fourth quadrant of the axis <NUM>, and the fourth longitudinal passage <NUM> may pass longitudinally from the second end <NUM> to the first end <NUM> as indicated by arrow <NUM>. The axis of the passage <NUM> may be parallel to the axis <NUM> in some embodiments. Coolant flow from the second end connecting passage <NUM> may be received by the fourth longitudinal passage <NUM> and directed longitudinally along the axis <NUM> from the second end <NUM> to the first end <NUM> for cooling the motor <NUM>. Flow from the fourth longitudinal passage <NUM> may be received in the first end discharge passage <NUM> (<FIG>).

The first end discharge passage <NUM> may be defined at the first end <NUM> between the end plate <NUM> and the first longitudinal end face <NUM> of the motor case <NUM>. The projections 215a, 215b and bearing mount <NUM> of the end plate <NUM> may nest, respectively, against the projections 221a, 215b, <NUM> of the motor case <NUM> to cooperatively define the respective fluid boundary <NUM> for directing flow of the coolant. As shown, the first end discharge passage <NUM> may be confined to the fourth quadrant of the e-charger <NUM> with respect to the axis <NUM> at the first end <NUM> of the e-charger <NUM>. Flow from the fourth longitudinal passage <NUM> may be received by the first end discharge passage <NUM> and turned radially, and redirected transversely and arcuately about the axis <NUM>, for example, to provide cooling to the bearing 214a. The first end discharge passage <NUM> may also be connected to the outlet <NUM>. Thus, hot coolant may exit the e-charger <NUM> via the outlet <NUM> to be replaced by fresh (lower temperature) coolant entering via the inlet <NUM>.

The e-charger <NUM> may be highly manufacturable. The outer housing <NUM> may be formed via casting methods from aluminum in some embodiments. The motor case <NUM> may also be cast, for example, from aluminum. The stator <NUM> and rotor <NUM> may be formed to a predetermined shape, size, and configuration, and the motor <NUM> may be assembled within the motor case <NUM>. Potting material may be used, and in some embodiments, the potting material may be conductive epoxy to maximize heat transfer through the motor <NUM> and motor case <NUM>. Once assembled, the motor case <NUM> may be inserted into and enclosed within the outer housing <NUM> as discussed above. Then, the compressor section <NUM> may be installed and attached to the motor section <NUM>. Subsequently, the e-charger <NUM> may be installed into the fuel cell system <NUM>, for example, by attaching the electrical connectors <NUM> to the control system <NUM>, by fluidly connecting the inlet <NUM> and the outlet <NUM> for airflow, and by fluidly connecting the inlet <NUM> and the outlet <NUM> for liquid coolant flow.

It will be appreciated that the cooling system <NUM> provides effective cooling. Also, the e-charger <NUM> is relatively compact, with a highly manufacturable design. Moreover, because the passages <NUM> are arranged in-series, there may be relatively few interfaces, seals, etc. to maintain. Additionally, this layout increases manufacturability. Furthermore, the cooling system <NUM> surrounds (jackets) the stator <NUM>, the bearings 214a, 214b, and other areas of e-charger <NUM> for highly effective cooling. Also, the cooling system <NUM> may maintain suitable fluid pressure throughout and may avoid significant pressure loss therethrough.

Claim 1:
An e-charger comprising:
a motor (<NUM>) that drives a shaft (<NUM>) for rotation about an axis (<NUM>), the axis extending through a first end (<NUM>) of the motor and a second end (<NUM>) of the motor;
a compressor wheel (<NUM>) that is attached to the shaft to be rotatably driven by the motor to thereby provide a compressed fluid stream;
a motor case (<NUM>) that encases the motor;
an outer housing (<NUM>) that houses the motor case; and
a cooling system (<NUM>) with an inlet, an outlet, and a plurality of passages (<NUM>) fluidly connecting the inlet and the outlet, the plurality of passages cooperatively defined by the outer housing and the motor case, the plurality of passages including a first longitudinal passage, a second longitudinal passage, and an end passage, the first longitudinal passage extending between the first and second ends of the motor, the second longitudinal passage extending between the second and first ends of the motor, the end passage disposed proximate the first end and fluidly connecting the first longitudinal passage and the second longitudinal passage, the cooling system configured for directing flow of the coolant from the inlet, through the first longitudinal passage in a first longitudinal direction with respect to the axis, radially and circumferentially through the end passage with respect to the axis, and back through the second longitudinal passage in a second longitudinal direction with respect to the axis.