Electric machine module cooling system and method

Some embodiments of the invention provide an electric machine module including a housing that defines a machine cavity. A coolant jacket can be at least partially defined by the housing. In some embodiments, a plurality of coolant apertures can be disposed through portions of the housing to fluidly connect the coolant jacket and the machine cavity. One or more solenoid assemblies can be at least partially supported by the housing and positioned substantially adjacent to at least some of the coolant apertures. The solenoid assemblies can be configured to regulate passage of a coolant into the machine cavity from the coolant jacket.

BACKGROUND

Some conventional electric machines include a stator assembly disposed around a rotor assembly. Some stator assemblies include a plurality of conductors positioned within a stator core. During operation of some electric machines, a current flows through the at least some of the conductors. In order to prevent potential short circuit events and or grounding incidents, some conventional configurations for stator assemblies require multiple insulation layers between and amongst the conductors. Moreover, during operation of some electric machines, heat energy can be generated by both the stator assembly and the rotor assembly, as well as some other components of the electric machine. The increase in heat energy produced by some elements of the electric machine can lead to inefficient machine operations.

SUMMARY

Some embodiments of the invention provide an electric machine module including a housing that can define a machine cavity. A coolant jacket can be at least partially defined by the housing. In some embodiments, a plurality of coolant apertures can be disposed through portions of the housing to fluidly connect the coolant jacket and the machine cavity. In some embodiments, one or more solenoid assemblies can be at least partially supported by the housing and positioned substantially adjacent to at least some of the coolant apertures. In some embodiments, the solenoid assemblies can be configured to regulate passage of a coolant into the machine cavity from the coolant jacket.

Some embodiments of the invention provide an electric machine module including a housing that can at least partially define a machine cavity. In some embodiments, a coolant jacket can be at least partially defined by the housing. In some embodiments, an electric machine comprising stator end turns can be at least partially disposed within the machine cavity so that portions of the electric machine can be at least partially circumscribed by the coolant jacket. In some embodiments, a plurality of coolant apertures can be disposed through portions of the housing to fluidly connect the coolant jacket and the machine cavity. At least some of the coolant apertures can be substantially adjacent to the stator end turns. In some embodiments, one or more solenoid assemblies, which can include a plunger, can be at least partially supported by the housing and can be positioned substantially adjacent to at least a portion of the plurality of coolant apertures. In some embodiments, the plunger of at least some of the solenoid assemblies can be configured and arranged to engage a portion of at least some of the plurality of coolant apertures. In some embodiments, an electronic control module can be in communication with at least a portion of the solenoid assemblies.

DETAILED DESCRIPTION

FIGS. 1 and 2illustrate an electric machine module10according to one embodiment of the invention. The module10can include a housing12comprising a sleeve member14, a first end cap16, and a second end cap18. An electric machine20can be housed within a machine cavity22at least partially defined by the sleeve member14and the end caps16,18. For example, the sleeve member14and the end caps16,18can be coupled via conventional fasteners (not shown), or another suitable coupling method, to enclose at least a portion of the electric machine20within the machine cavity22. In some embodiments, the housing12can comprise a substantially cylindrical canister15coupled to an end cap17, as shown inFIG. 2. Further, in some embodiments, the housing12can comprise materials that can generally include thermally conductive properties, such as, but not limited to aluminum or other metals and materials capable of generally withstanding operating temperatures of the electric machine. In some embodiments, the housing12can be fabricated using different methods including casting, molding, extruding, and other similar manufacturing methods.

In some embodiments, the housing12(i.e., the sleeve member14and end caps16,18and/or the canister15and the end cap17) can be disposed within an additional support member (not shown). For example, the support member can comprise another housing (e.g., a transmission housing) into which the housing12can be disposed or to which the housing12can be coupled. By way of example only, in some embodiments, a recess can be defined between the housing12and the support member. For example, as discussed in greater detail below, one or more coolant jackets can be defined between the housing12and the support member.

The electric machine20can include a rotor assembly24, a stator assembly26, and bearings28, and can be disposed about a shaft30. As shown inFIG. 1, the stator assembly26can substantially circumscribe at least a portion of the rotor assembly24. In some embodiments, the rotor assembly24can also include a rotor hub32or can have a “hub-less” design (not shown).

In some embodiments, the electric machine20can be operatively coupled to the housing12. For example, the electric machine20can be fit within the housing12. In some embodiments, the electric machine20can be fit within the housing12using an interference fit, a shrink fit, other similar friction-based fits that can at least partially operatively couple the machine20and the housing12. For example, in some embodiments, the stator assembly26can be shrunk fit into the module housing12. Further, in some embodiments, the fit can at least partially secure the stator assembly26, and as a result, the electric machine20, in axial, radial and circumferential directions. In some embodiments, during operation of the electric machine20the fit between the stator assembly26and the housing12can at least partially serve to transfer torque from the stator assembly26to the housing12. In some embodiments, the fit can result in a generally greater amount of torque retained by the module10.

The electric machine20can be, without limitation, an electric motor, such as a hybrid electric motor, an electric generator, or a vehicle alternator. In one embodiment, the electric machine20can be a High Voltage Hairpin (HVH) electric motor, an interior permanent magnet electric motor, or an induction motor for hybrid vehicle applications.

As shown inFIG. 3, in some embodiments, the stator assembly26can comprise a stator core34and a stator winding36at least partially disposed within a portion of the stator core34. For example, in some embodiments, the stator core34can comprise a plurality of laminations38. Referring toFIG. 4, in some embodiments, the laminations38can comprise a plurality of substantially radially-oriented teeth40. In some embodiments, as shown inFIG. 3, when at least a portion of the plurality of laminations38are substantially assembled, the teeth40can substantially align to define a plurality of slots42that are configured and arranged to support at least a portion of the stator winding36. As shown inFIG. 4, in some embodiments, the laminations38can include sixty teeth40, and, as a result, the stator core28can include sixty slots42. In other embodiments, the laminations38can include more or fewer teeth40, and, accordingly, the stator core34can include more or fewer slots42. Moreover, in some embodiments, the stator core34can comprise an inner perimeter41and an outer perimeter43. For example, in some embodiments, the stator core34can comprise a substantially cylindrical configuration so that the inner and outer perimeters41,43can comprise inner and outer diameters, respectively. However, in other embodiments, the stator core34can comprise other configurations (e.g., square, rectangular, elliptical, regular or irregular polygonal, etc.), and, as a result, the inner and outer perimeters41,43can comprise other dimensions.

In some embodiments, the stator winding36can comprise a plurality of conductors44. In some embodiments, the conductors44can comprise a substantially segmented configuration (e.g., a hairpin configuration), as shown inFIGS. 3 and 5. For example, in some embodiments, at least a portion of the conductors44can include a turn portion46and at least two leg portions48. The turn portion46can be disposed between the two leg portions48to connect the two leg portions48, which can be substantially parallel. Moreover, in some embodiments, the turn portion46can comprise a substantially “u-shaped” configuration, although, in some embodiments, the turn portion46can comprise a v-shape, a wave shape, a curved shape, and other shapes. Additionally, in some embodiments, as shown inFIG. 5, at least a portion of the conductors44can comprise a substantially rectangular cross section. In some embodiments, at least a portion of the conductors44can comprise other cross-sectional shapes, such as substantially circular, square, hemispherical, regular or irregular polygonal, etc. In some embodiments, the conductors44can comprise other configurations (e.g., substantially non-segmented configuration). In some embodiments, as shown inFIG. 3, at least a portion of the conductors44can be positioned substantially within the slots42. For example, in some embodiments, the stator core34can be configured so that the plurality of slots42are substantially axially arranged. The leg portions48can be inserted into the slots42so that at least some of the leg portions48can axially extend through the stator core34. In some embodiments, the leg portions48can be inserted into neighboring slots42. For example, the leg portions48of a conductor44can be disposed in slots that are distanced approximately one magnetic-pole pitch apart (e.g., six slots, eight slots, etc.). In some embodiments, a plurality of conductors44can be disposed in the stator core34so that at least some of the turn portions46of the conductors44axially extend from the stator core34at a first axial end50of the stator core34and at least some of the leg portions48axially extend from the stator core34at a second axial end52of the stator core34. In some embodiments, at least a portion of the conductor44regions that axially extend from the core34at the axial ends50,52can comprise stator end turns54.

In some embodiments, the conductors44can be generally fabricated from a substantially linear conductor44that can be configured and arranged to a shape substantially similar to the conductor inFIG. 5. For example, in some embodiments, a machine (not shown) can apply a force (e.g., bend, push, pull, other otherwise actuate) to at least a portion of a conductor44to substantially form the turn portion46and the two leg portions48of a single conductor44.

In some embodiments, at least some of the leg portions48can comprise multiple regions. The leg portions48can comprise in-slot portions56, angled portions58, and connection portions60. In some embodiments, as previously mentioned, the leg portions48can be disposed in the slots42and can axially extend from the first end50to the second end52. In some embodiments, after insertion, at least a portion of the leg portions48positioned within the slots42can comprise the in-slot portions56. In some embodiments, in some or all of the slots42, the leg portions48can be substantially radially aligned, as shown inFIG. 3. In some embodiments, in some or all of the slots42, the leg portions48can comprise other configurations.

In some embodiments, at least some of stator end turns54extending from stator core34at the second axial end52can comprise the angled portions58and the connection portions60. In some embodiments, after inserting the conductors44into the stator core34, the leg portions48extending from the stator core34at the second axial end52can undergo a twisting process (not shown) that can lead to the formation of the angled portions58and the connection portions60. For example, in some embodiments, the twisting process can give rise to the angled portions58at a more axially inward position and the connection portions60at a more axially outward position, as shown inFIGS. 3 and 5. In some embodiments, after the twisting process, the connection portions60of at least a portion of the conductors44can be immediately adjacent to connection portions60of other conductors44. As a result, the connection portions60can be coupled together to form one or more stator windings36. In some embodiments, the connection portions60can be coupled via welding, brazing, soldering, melting, adhesives, or other coupling methods. Additionally, in some embodiments, the angled portions58and the connection portions60can extend from the first axial end50and can be configured and arranged in a similar manner as some previously mentioned embodiments.

In some embodiments, some components of the electric machine20such as, but not limited to, the rotor assembly24, the stator assembly26, and the stator end turns54, can generate heat during operation of the electric machine20. For example, as reflected by the temperature values illustrated inFIG. 6, different regions of the stator assembly26(e.g., different regions of the stator end turns54) can operate at different temperatures under different conditions. Under some or all conditions (e.g., varying operating speeds, loads, and operational direction), different regions of the stator assembly26can operate at greater and lesser temperatures. Moreover, during module10operations, some or all of the conditions, such as speed, load, and/or direction can change so that operating temperature in different regions can change as a result of the change in conditions. During module10operations, temperature in different regions of the stator end turns54can continuously change during operations of the module10.

In order to create an optimized power density for the electric machine module10, it can be desirable for the electric machine20to continuously operate at a high performance level, which can be achieved by relatively accurate and adequate cooling. In some conventional electric machine modules, cooling configurations can be fixed for the life of the module10(i.e., the cooling configuration can be predetermined during the design stage of the module10and incorporated in the physical design of the module10). In some or all of these conventional modules, cooling (e.g., coolant flowing from a coolant jacket to the stator end turns54) cannot be adapted to the thermal variations in the stator end turns54. As a result, accurate and adequate cooling cannot be consistently achieved because under many conditions, some or all of the conventional module cooling configurations are not able to provide cooling to the changing thermal patterns of the stator end turns54. As discussed below, some embodiments of the invention can comprise dynamic cooling configurations to enable some electric machine modules10to operate at or near continuous peak performance levels.

As shown inFIG. 1, in some embodiments, the housing12can comprise a coolant jacket62. For example, in some embodiments, the sleeve member14can include an inner surface64and an outer surface66and the coolant jacket62can be positioned substantially between the surfaces64,66. As previously mentioned, in some embodiments, the canister15and end cap17can be disposed in another housing and a recess (not shown) can be defined between an outer perimeter of the canister15and the other housing (not shown). In some embodiments, the recess can comprise the coolant jacket62. In some embodiments, the coolant jacket62can substantially circumscribe at least a portion of the electric machine20. For example, the coolant jacket62can substantially circumscribe at least a portion of the outer perimeter43of the stator assembly26, including the stator winding36as it extends on both the first end50and the second end52(i.e., the stator end turns54).

Further, in some embodiments, the coolant jacket62can contain a coolant that can comprise transmission fluid, ethylene glycol, an ethylene glycol/water mixture, water, oil, motor oil, a mist, a gas, or another substance capable of receiving heat energy produced by the electric machine module10. The coolant jacket62can be in fluid communication with a coolant source (not shown) which can pressurize the coolant prior to or as it is being dispersed into the coolant jacket62, so that the pressurized coolant can circulate through the coolant jacket62.

Also, in some embodiments, the inner surface64and/or the canister15can include coolant apertures68so that the coolant jacket62can be in fluid communication with the machine cavity22. In some embodiments, the coolant apertures68can be positioned substantially adjacent to the stator end turns54. For example, in some embodiments, as the pressurized coolant circulates through the coolant jacket62, at least a portion of the coolant can exit the coolant jacket62through the coolant apertures68and enter the machine cavity22. Also, in some embodiments, the coolant can contact the stator end turns54, which can lead to at least partial cooling, at least partially depending upon machine20operations. After exiting the coolant apertures68, at least a portion of the coolant can flow through portions of the machine cavity22and can contact various module10elements, which, in some embodiments, can lead to at least partial cooling of the module10.

In some embodiments, at least a portion of the coolant can originate from and/or substantially adjacent to the rotor assembly24. For example, in addition to portions of the stator assembly26generating thermal energy, the rotor assembly24can also generate thermal energy and may require cooling for enhanced performance. In some embodiments, portions of the rotor assembly24, such as the shaft30and/or the rotor hub32can comprise one or more channels (not shown) that are in fluid communication with the coolant source. As a result, in addition to, or lieu of coolant entering the machine cavity22via the coolant jacket62, at least a portion of the coolant can enter the machine cavity22via the rotor assembly24in a manner substantially similar to the coolant flow paths disclosed in U.S. patent application Ser. No. 13/016,940, which is assigned to the same assignee as the present application and is herein incorporated by reference in its entirety.

In some embodiments, the electric machine module10can be configured to enable improved and/or optimized coolant distribution through at least some of the coolant apertures68. As shown inFIGS. 7 and 8, in some embodiments, the electric machine module10can comprise one or more valves85coupled to one or more solenoid assemblies70disposed within, supported by, and/or coupled to the housing12so that they are substantially adjacent to some or all of the coolant apertures68. For example, as discussed below, some or all of the solenoid assemblies70can be configured and arranged to regulate at least a portion of coolant flow from the coolant jacket62into the machine cavity22. As shown inFIG. 7, in some embodiments, the solenoid assemblies70can be coupled to a portion of the housing12. For example, at least a portion of some of the solenoid assemblies70can be at least partially positioned between the inner surface64and the outer surface66and/or the canister15and the additional housing. As a result of this positioning, in some embodiments, at least a region of some or all of the solenoid assemblies70can extend into the coolant jacket62, which can lead to regulation of coolant flow from the coolant jacket62to the machine cavity22.

In some embodiments, the solenoid assemblies70can comprise a core72, a plunger74, one or more coils76, and a spring78. For example, some or all of the solenoid assemblies70can comprise a conventional solenoid configuration, and in some embodiments, some of the solenoid assemblies70can comprise non-conventional solenoid configurations. In some embodiments, the cores72can be coupled to at least a portion of the housing12. For example, the cores72can be disposed through and coupled to at least a portion of the housing12and arranged around at least a portion of a circumference of the housing12so that the solenoid assemblies70at least partially circumscribe portions of the electric machine20(e.g., the stator assembly26, including the stator end turns54). Moreover, in some embodiments, the cores72can be positioned so that at least a portion of the solenoid assemblies70(e.g., the plunger74) are substantially adjacent (e.g., radially outward) to at least some of the coolant apertures68, as shown inFIG. 7.

As previously mentioned, in some embodiments, some or all of the solenoid assemblies70can comprise a conventional solenoid configuration, as shown inFIGS. 7 and 8. For example, the plunger74can be at least partially disposed within the core72and configured and arranged to move within the core72. In some embodiments, the core72and/or the plunger74can comprise an iron-containing material, a steel-containing material, or any other material capable of functioning in an electromagnetic capacity. In some embodiments, some or all of the solenoid assemblies70can comprise one or more alternative configurations. For example, to reduce power consumption, noise, size occupied by the solenoid assembly70, and weight of the solenoid assembly70, at least a portion of the plunger74can comprise a non-iron or steel-containing material and the solenoid assembly70can be actuated by an iron or steel-containing plunger (e.g., servo-actuated).

In some embodiments, the plunger74can be configured and arranged to include multiple perimeters. For example, as shown inFIG. 7, the plunger can comprise a first region80and a second region82. In some embodiments, the first region80can comprise a lesser perimeter relative to the second region82. As a result, when the solenoid assembly70is inactive, a gap84can be defined between the first region80and an inner periphery of the core72. Furthermore, in some embodiments, the spring78can be disposed around at least a portion of the first region80of the plunger74and can contact the inner periphery of the core72to bias the plunger74when the solenoid assembly70is in an inactive state. In some embodiments, when the solenoid assembly70is inactive, the plunger74can be disposed so that the valve85can be positioned immediately adjacent to one or more coolant apertures68, as shown inFIG. 7. For example, a first end of the plunger74can comprise the valve85, which can be configured and arranged to seal the coolant aperture68so that no material volumes of coolant can enter the machine cavity22through the coolant apertures68immediately adjacent to inactive solenoid assemblies70. In some embodiments, some or all of the coolant apertures68can comprise a valve seat86that can be configured and arranged to receive a portion of the valve85to substantially seal the coolant apertures68so that no material volumes of coolant can enter the machine cavity22, as shown inFIGS. 8A and 8B.

In some embodiments, the coil76can be at least partially disposed (e.g., wound) around an outer periphery of the core72and can be connected to one or more current sources. As a result of the coil's76positioning around the outer periphery of the core72, a magnetic field can be generated when a current circulates through the coil76. Moreover, the magnetic field generated by the current circulating through the coil76can cause the plunger74to move. The magnetic field can cause the plunger74to move to substantially or completely to eliminate the gap84between the plunger74and the inner periphery of the core72. For example, the second region82of the plunger74can radially and/or axially move (e.g., can be pulled by the magnetic field) to a position substantially similar to where the first region80was disposed when the solenoid assembly70was inactive, which can lead to at least partial compression of the spring78. In some embodiments, as long as current circulates through the coil76and the solenoid assembly70comprises a magnetic field, the second region82can remain in a substantially similar position (i.e., a position substantially similar to the position of the first region80when the solenoid assembly70is inactive). Additionally, in some embodiments, at least some of the solenoid assemblies70can be configured and arranged so that the coolant apertures68are generally unobstructed and, upon energization, the solenoid assemblies70can substantially or completely seal the coolant apertures68. Accordingly, in some embodiments, the solenoid assemblies70can be configured and arranged to enable a coolant flow upon activation of one or more of the assemblies70. In some embodiments, at least a portion of the solenoid assemblies70can be configured and arranged to obstruct coolant flow through the coolant apertures68upon activation of one or more of the assemblies70.

Furthermore, in some embodiments, as a result of the plunger74moving, the valve85can disengage from the valve seat86to enable coolant to flow into the machine cavity22, which can lead to cooling of the stator end turns54and/or other elements of the electric machine module10, as shown inFIG. 8B. Conversely, when current either substantially or completely ceases flowing through the coil76, the magnetic field can weaken and/or dissipate, which can lead to the second region82returning to its original position. For example, the plunger74can return to its original position because the force of the magnetic field retaining the second region82in position can weaken to a point where the biasing force of the spring78can overcome the magnetic field and move the plunger74back to the original position to form the gap84between the first region80and the inner periphery of the core72. As a result, the valve85can engage the valve seat86to substantially seal one or more coolant apertures68to prevent material volumes of coolant from entering the machine cavity22, as shown inFIG. 8A.

In some embodiments, some or all of the solenoid assemblies70can be activated and/or deactivated to coordinate electric machine module10cooling. In some embodiments, one or more sensors (e.g., temperature sensors89) can be coupled to portions of the electric machine module10. For example, in some embodiments, a plurality of temperature sensors89can be coupled to the inner surface64and/or portions of the stator assembly26, such as the stator end turns54and/or the stator core34. The temperature sensors89can be disposed around some or all of the circumference of the stator end turns54at regular and/or irregular intervals at the first axial end50and/or the second axial end52of the stator core34. In some embodiments, the temperature sensors89can be disposed in other locations so that operating temperatures of the stator assembly26and other portions of the module10can be detected by the sensors89. In some embodiments, the positioning of some or all of the temperature sensors89can be at least partially determined by ranges in temperature associated with various machine speeds, loads, and/or directions. In some embodiments, the module10can comprise any other devices that are configured and arranged to measure temperature of the electric machine module10.

In some embodiments, some or all of the sensors89can be in communication (e.g., wired and/or wireless communication) with some or all of the solenoid assemblies70and/or an electronic control module88, as shown inFIG. 7. For example, some or all of the solenoid assemblies70can be activated upon receiving input from at least a portion of the sensors89. In other embodiments, some or all of the sensors89can communicate temperature data to the electronic control module88. For example, in some embodiments, the electric machine module10can be installed within a vehicle and the temperature sensors89can be in communication with the electronic control module88of the vehicle. In other embodiments, the electric machine module10can comprise one or more electronic control modules88. Regardless of positioning, the electronic control module88can be in communication with some or all of the solenoid assemblies70and can be configured and arranged to activate and/or deactivate the solenoid assemblies70at least partially based upon temperature data received from the sensors89.

In some embodiments, the electronic control module88can comprise one or more programs designed to optimize cooling of the electric machine module10. For example, the electronic control module88can control the current flow to the coils76of at least some of the solenoid assemblies70. As a result of controlling current flow, the electronic control module88can also control coolant flow through the valve seat86and at least a portion of the coolant apertures68. Upon receiving temperature data from one or more sensors89indicating that the temperature in one or more regions of the stator end turns54is over a predetermined threshold, the electronic control module88can enable current flow to the coils76of some or all of the solenoid assemblies70substantially adjacent to the location where the temperature sensor is detecting an over-temperature condition. For example, if the electronic control module88receives data from some or all of the temperature sensors89and some of the sensors89substantially adjacent to a “twelve o′clock” and a “nine o′clock” position of the stator assembly26, as illustrated inFIG. 6, transmit data suggesting that these regions of the stator end turns54are operating above a predetermine threshold, the electronic control module88can enable current flow to at least a portion of the solenoid assemblies70substantially adjacent to the “twelve o′clock” and “nine o′clock” positions. Coolant can exit the coolant jacket62(i.e., because the valve85at least partially disengages from the valve seat86to enable coolant efflux from the coolant jacket62) and contact the stator end turns54, at least some of which are operating at temperatures at or above the predetermined threshold.

In some embodiments, current can flow to the selected solenoid assemblies70for a predetermined time to enable a predetermined volume of coolant to exit the coolant jacket62. In other embodiments, current can flow to the selected solenoid assemblies70until the temperature sensors89adjacent to the activated solenoid assemblies70transmit temperature data to the electronic control module88that is indicative of the temperature of the stator end turns54returning to an acceptable temperature range. Additionally, in some embodiments, current can continuously flow through the coils76of the activated solenoid assemblies70. In other embodiments, current can be controlled via pulse-width modulation so that the plunger74is sealing and unsealing the coolant apertures68to control coolant flow from the coolant jacket62into the machine cavity22. For example, if the current was configured to flow to the solenoid assemblies70at a 25% duty cycle, about one-quarter of the volume of coolant would flow through the coolant apertures68, compared to a solenoid assembly70operating at a 100% duty cycle (i.e., in a constantly energized state). Moreover, in some embodiments, the housing12can comprise one or more coolant apertures68functioning without a solenoid assembly70so that coolant can substantially continuously flow from the coolant jacket62into the machine cavity22. Accordingly, some regions of the module10can experience substantially continuous changes in coolant flow from the coolant jacket62depending on the temperature sensed (e.g., solenoid assemblies70activating and deactivating as a result of temperature increases and decreases at the stator end turns54).

In some embodiments, the electronic control module88can comprise alternative control capabilities. In some embodiments, in lieu of being in communication with some or all of the temperature sensors89, the electronic control module can be preprogrammed with temperature data so that the control module88can activate some or all of the solenoid assemblies70at predetermined times. For example, temperature data can be gathered during assembly and/or design of the electric machine module10that is indicative of temperature of different sections of the stator end turns54operating under different conditions (e.g., load, direction, and speed). As a result, during operation of the electric machine module10, the electronic control module can assess the operational state of the module10(e.g., load magnitude, direction of the machine20, speed of the machine20, etc.) and can compare the operational state to the preprogrammed temperature data to determine which solenoid assemblies70should be energized to cool stator end turns54that are likely to exceed a desirable temperature based at least partially on the operational state.

In some embodiments, in addition to, or in lieu of the electronic control module88and/or the temperature sensors89, some or all of the solenoid assemblies70can comprise a passive temperature regulating system (not shown). For example, some or all of the solenoid assemblies70can comprise a conventional thermostat or other passively-operating temperature sensing devices so that when the thermostat detects thermal output from the electric machine module10that exceeds the predetermined threshold, the conventional thermostat can activate some or all of the solenoid assemblies70. Moreover, in some embodiments, one thermostat can be in communication with each of the solenoid assemblies70, each solenoid assembly70can be in communication with a thermostat, and some of the solenoid assemblies70can be in communication with one or more thermostats.

Some embodiments of the invention offer improvements relative to some conventional cooling configurations. As previously mentioned, some conventional cooling configurations can be substantially fixed at the design stages of the module10because only coolant apertures68can be included in the housing12to enable coolant flow. As a result, at least some conventional cooling configurations fail to provide cooling capabilities that are adaptive to changes in module10conditions, such as load, direction, and speed. Some embodiments of the invention enable coolant flow to be optimized so that coolant is provided to areas of the module10that are operating at higher temperatures. The solenoid assemblies70can enable optimized coolant flow so that accurate and adequate cooling can occur and the electric machine module10can operate at or near peak performance levels for an extended duration. Moreover, by being able to optimize cooling based on temperature, electric machine modules10can be employed in any number of configurations and applications. For example, electric machine modules10can be installed in any number of applications and the optimized cooling configuration including the solenoid assemblies70can be employed to provide coolant regardless of positioning or use of the module10because of its temperature-based cooling.

In some embodiments, coolant flow controlled by the solenoid assemblies70can at least partially impact rotor assembly24cooling. As previously mentioned, in some embodiments, a volume of coolant can enter the machine cavity22after flowing through portions of the rotor assembly24and the shaft30in addition to coolant flowing from the coolant jacket62. As a result of coolant flowing through portions of the rotor assembly24, at least a portion of the torque generated by the rotor assembly24moving during electric machine20operations can be lost. Some embodiments of the invention can enable cooling of the rotor assembly24and minimize the torque loss stemming from coolant flow through the rotor assembly24. For example, in some embodiments, the coolant jacket62and the rotor assembly24and shaft30can be coupled to one or more of the same coolant sources. In some embodiments, some or all of the solenoid assemblies70can be energized so that coolant can flow through some or all of the coolant apertures68. As a result, at least a portion the coolant that would normally flow through the shaft30and the rotor assembly24can be diverted through the open coolant apertures68leading to minimized torque losses because of the decreased coolant flow through the rotor assembly24. Moreover, although the rotor assembly24will comprise a lesser coolant flow relative to when coolant is not flowing through some of the coolant apertures68, at least a portion of the rotor assembly24can still be cooled because of the increased coolant flow through the coolant apertures68leading to greater volumes of coolant entering the machine cavity22.