Patent 11218063 - Segmented switched reluctance motor for powertrain electrification > Description
This application is a divisional and claims priority to U.S. patent application Ser. No. 15/285,217, filed on Oct. 4, 2016 (now allowed). The entire disclosure of the above application is incorporated herein by reference.
The present disclosure relates to powertrain systems for motor vehicles, and more particularly to a segmented, switched reluctance motor for forming an electrified powertrain for a motor vehicle, and which is able to be integrated into a conventional transmission housing of a transmission of the vehicle.
This section provides background information related to the present disclosure which is not necessarily prior art.
A traditional front wheel drive (FWD) vehicle often has a transverse mounted powertrain, which typically includes an engine, transmission, flywheel, and torque converter. Those of ordinary skill in the art will readily appreciate that space is at a premium in this location and there is virtually no additional room for an electric motor to form a type of P2 hybrid that is known as a “P2 hybrid” in which the electric motor is disposed between the internal combustion engine and the transmission, the electric motor is not directly coupled to the internal combustion and the rotational speeds of the internal combustion engine and the electric motor are the same. This is illustrated in
Accordingly, there is a need for a P2 hybrid powertrain construction that integrates the electric motor between the internal combustion engine and the transmission without tangibly increasing the overall length of the powertrain.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
In one aspect the present disclosure relates to a transmission system comprising a transmission subsystem, a transmission housing for housing the transmission subsystem, and a rotor operably associated with the transmission subsystem. The rotor is supported for rotation within the transmission housing and has a weight and dimension to act as a flywheel. At least one stator pole segment is housed within the transmission housing, and has at least one stator winding thereon. The stator pole segment is secured to the transmission housing in a manner so that a portion thereof is in proximity to a surface of the rotor. An inverter is included which is in electrical communication with the stator winding of the stator pole segment. The inverter is configured to electrically energize the winding of the stator pole segment to cause rotation of the rotor.
In another aspect the present disclosure relates to a transmission system. The transmission system may have a transmission subsystem, a transmission housing having at least two openings, and a rotor operably coupled to the transmission subsystem. The rotor is supported for rotation within the transmission housing and has a weight and dimension to act as a flywheel. At least two independent stator pole segments are mounted within the plurality of openings. Each independent stator pole segment has a stator winding thereon, and the stator pole segments are spaced generally equidistantly circumferentially apart from one another, and secured to the transmission housing in a manner so that a portion of each stator pole segment is in proximity to a peripheral surface of the rotor. The independent stator pole segments collectively form a switched reluctance motor configured to power an engine coupled to the transmission subsystem.
In still another aspect the present disclosure relates to a method for forming a transmission. The method may comprise mounting a transmission subsystem within a transmission housing. The method may also involve coupling a rotor with the transmission subsystem and supporting the rotor for rotational movement within the transmission housing. The rotor may be configured to have a weight and dimensions to act as a flywheel. The method may also involve supporting a plurality of at least two independent stator pole segments, each having a stator winding thereon, and spaced generally equidistantly circumferentially apart from one another, at least partially within the transmission housing. The independent stator pole segments may also be supported in a manner so that a portion of each said independent stator pole segment is in proximity to a peripheral surface of the rotor. An inverter may be used which is in electrical communication with the stator windings of the independent stator pole segments, and configured to electrically energize the independent stator pole segments, to cause rotation of the rotor.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
A principal advantage of the system 10 is the integrated, segmented stator system 20 (hereinafter simply “stator system” 20). The stator system 20 is able to be integrated into transmission 14 without increasing the overall axial length of the powertrain 10, which is especially important when the powertrain is located in the P2 location of the vehicle, where space is very limited. With further reference to
The stator pole segments 34a-34c are spaced equidistantly around the transmission housing 18 and each includes a coil winding assembly 38a-38c thereon. Thus, a plurality of coil windings make up coil winding assembly 38a, a separate plurality of coil windings make up coil winding assembly 38b and still another separate plurality of coil windings make up coil winding assembly 38c. The stator pole segments 34a-34c are shown projecting slightly outwardly from an outer surface 40 of the transmission housing 18, although depending on the size of the transmission housing, the stator pole segments could be contained entirely within the transmission housing 18. The stator pole segments 34a-34c are positioned such that a small axial air gap is present between radially inward surfaces of each stator pole segment and an outer surface of the gear 24 on the outer perimeter edge of the rotor 22. However, depending on the electromagnetic design requirements, the gap could comprise a radial gap, or possibly even a combination of axial and radial gaps.
As noted above, the equidistant spacing of the stator pole segments 34a-34c around the rotor 22 is preferred because it also eliminates the possibility of creating an unbalanced force vector on the bearing(s) (not shown) supporting the rotor 22 on the input shaft 26. A segmented rotor position sensor 42 is positioned closely adjacent the rotor 22 to detect an angular position of the rotor in real time and to supply an electrical angular position signal to the inverter 16, as is otherwise well known for commutating switched reluctance motors. The stator system 20 with its stator pole segments 34a-34c, the inverter subsystem 16 and the rotor position sensor 42 cooperatively form a switched reluctance motor 44.
It will also be understood that the rotor 22 forms a salient pole component, as is standard with any switched reluctance motor. To commutate the switched reluctance motor 44, selected pairs of the stator coils in each pole segment 34a-34c are energized at a time by the inverter 16 to pull the rotor 22 into alignment with the energized stator coil pole segments, as is well understood in the art. The inverter 16 operates in a closed loop fashion using the feedback signals from the rotor position sensor 42, which is detecting the presence of one or more elements (not shown) on the rotor 22, and detected currents in the coil winding assemblies 38a-38c, to determine which pair of the stator pole segments 34a-34c need to be energized to maintain rotational motion of the rotor 22. The complexity of the inverter 16 will increase as the number of stator coils and pole segments 34 increases.
A particular advantage of the system 10 is that the rotor 22 has a relatively large diameter and a weight that is similar or identical to that of a conventional flywheel typically used with automotive transmissions. This enables the motor 44 to provide higher torque values to the engine's crankshaft, which is advantageous when using the switched reluctance motor 44 to start the engine 12. The torque seen at the engine's 12 crankshaft will largely be a function of the rotor 22 diameter and the electromagnetic force created in the stator system 20.
In the embodiment shown in
It will also be appreciated that packaging of the stator system 20 may be accomplished in a plurality of ways depending upon the specific application and the space available where the stator system is being used, as well as the torque output required. For example,
The powertrain 10 thus enables the switched reluctance motor 44 to be integrated into the P2 location between an engine and an otherwise conventional transmission, without increasing the overall axial length of the engine/transmission combination. This enables powertrain 10 to be used with transverse mounted engines where even a slight increase in axial length of the engine/transmission combination may not be possible because of space restrictions and interference from suspension and/or chassis components of the vehicle. As such, the powertrain 10 enables electrification of a vehicle powertrain in applications where the integration of a self-contained electric motor into the powertrain would not be feasible because of space constraints.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.