Patent Publication Number: US-2017370446-A1

Title: Inline electromechanical variable transmission system

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 15/693,176, filed Aug. 31, 2017, which is a continuation-in-part of: U.S. application Ser. No. 14/918,221, filed Oct. 20, 2015; U.S. application Ser. No. 15/595,443, filed May 15, 2017, which is a continuation of U.S. application Ser. No. 14/624,285, filed Feb. 17, 2015, now U.S. Pat. No. 9,651,120; U.S. application Ser. No. 15/595,511, filed May 15, 2017, which is a continuation of U.S. application Ser. No. 14/792,532, filed Jul. 6, 2015, now U.S. Pat. No. 9,650,032, which is a continuation-in-part of U.S. application Ser. No. 14/624,285, filed Feb. 17, 2015, now U.S. Pat. No. 9,651,120; and U.S. application Ser. No. 15/601,670, filed May 22, 2017, which is a continuation of U.S. application Ser. No. 14/792,535, filed Jul. 6, 2015, now U.S. Pat. No. 9,656,659, which is a continuation-in-part of U.S. application Ser. No. 14/624,285, filed Feb. 17, 2015, now U.S. Pat. No. 9,651,120, all of which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     Internal combustion engine vehicles, hybrid vehicles, and electric vehicles, among other types of vehicles, include transmissions. Traditional vehicle transmissions use gears and gear trains to provide speed and torque conversions from a rotating power source (e.g., an engine, a motor, etc.) to another device (e.g., a drive shaft, wheels of a vehicle, etc.). Transmissions include multiple gear ratios selectively coupled to the rotating power source with a mechanism. The mechanism may also selectively couple an output to the various gear ratios. 
     SUMMARY 
     One exemplary embodiment relates to a drive system for a vehicle. The drive system includes a first planetary gear set, a second planetary gear set directly coupled to the first planetary gear set, an engine directly coupled to the first planetary gear set with a connecting shaft, a first electromagnetic device selectively coupled to the first planetary gear set, a second electromagnetic device directly coupled to the second planetary gear set, and an output shaft coupled to the first planetary gear set. The first planetary gear set, the second planetary gear set, and the connecting shaft are radially aligned. The first electromagnetic device includes a first shaft, and the second electromagnetic device includes a second shaft. The first shaft and the second shaft are radially aligned with the first planetary gear set, the second planetary gear set, and the connecting shaft. The connecting shaft extends through the second electromagnetic device and through the second planetary gear set to the first planetary gear set. The output shaft is radially aligned with the first planetary gear set, the second planetary gear set, and the connecting shaft to thereby form a straight-thru transmission arrangement. 
     Another exemplary embodiment relates to a drive system for a vehicle. The drive system includes a first gear set, a second gear set, a connecting shaft coupling an engine to the first gear set, a first electromagnetic device selectively coupled to the first gear set, a second electromagnetic device coupled to the second gear set, and an output shaft. The first gear set includes a first sun gear, a first ring gear, a first plurality of planetary gears coupling the first sun gear to the first ring gear, and a first carrier rotationally supporting the first plurality of planetary gears. The second gear set includes a second sun gear, a second ring gear, a second plurality of planetary gears coupling the second sun gear to the second ring gear, and a second carrier rotationally supporting the second plurality of planetary gears. The first carrier is directly coupled to the second carrier. The output shaft is directly coupled to the first carrier and configured to transport power from the first electromagnetic device, the second electromagnetic device, and the engine to a tractive element of the vehicle. The output shaft is aligned with the connecting shaft, the first electromagnetic device, and the second electromagnetic device to thereby form a straight-thru transmission arrangement 
     Another exemplary embodiment relates to a vehicle that includes a multi-mode transmission, an engine, and a drive axle. The multi-mode transmission includes a first gear set including a planetary gear set having a planetary gear carrier, a second gear set, a first motor/generator selectively coupled to the first gear set, a second motor/generator coupled to the second gear set, and an output shaft directly coupled to the planetary gear carrier of the first gear set and configured to selectively receive rotational mechanical energy from the first motor/generator and the second motor/generator. The planetary gear carrier and the second gear set are directly coupled. The engine is directly coupled to the first gear set and selectively coupled to the second gear set. The drive axle is coupled to the output shaft of the multi-mode transmission. 
     The invention is capable of other embodiments and of being carried out in various ways. Alternative exemplary embodiments relate to other features and combinations of features as may be recited herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which: 
         FIG. 1  is a schematic view of a vehicle having a drive train, according to an exemplary embodiment; 
         FIG. 2  is a detailed schematic view of the drive train of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 3  is a schematic diagram of a control system for the drive train of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 4  is a detailed schematic view of a drive train configured in a neutral/startup mode of operation, according to an exemplary embodiment; 
         FIG. 5  is a detailed schematic view of a drive train configured in a neutral/startup mode of operation, according to another exemplary embodiment; 
         FIG. 6  is a detailed schematic view of a drive train configured in a low range mode of operation, according to an exemplary embodiment; 
         FIG. 7  is a detailed schematic view of a drive train configured in a mid range mode of operation, according to an exemplary embodiment; 
         FIG. 8  is a detailed schematic view of a drive train configured in a high range mode of operation, according to an exemplary embodiment; 
         FIG. 9  is a detailed schematic view of a drive train configured in an intermediate shift mode of operation, according to an exemplary embodiment; 
         FIG. 10  is a detailed schematic view of a drive train configured in a low speed reverse mode of operation, according to an exemplary embodiment; 
         FIG. 11  is a detailed schematic view of a drive train configured in a mid speed reverse mode of operation, according to an exemplary embodiment; 
         FIG. 12  is a detailed schematic view of a drive train configured in a power generation mode of operation, according to an exemplary embodiment; and 
         FIG. 13  is a detailed schematic view of a drive train configured in an electric PTO mode of operation, according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting. 
     According to an exemplary embodiment, a multi-mode inline electromechanical variable transmission is provided as part of a vehicle and is selectively reconfigurable between a plurality of operating modes. The vehicle may also include an engine and one or more tractive elements (e.g., wheel and tire assemblies, etc.). The multi-mode inline electromechanical variable transmission may include a first electromagnetic device and a second electromagnetic device. In one embodiment, at least one of the first electromagnetic device and the second electromagnetic device provides rotational mechanical energy to start the engine. In another embodiment, the engine provides a rotational mechanical energy input to both the first and second electromagnetic devices such that each operates as a generator to generate electrical energy. In still other embodiments, one of the first electromagnetic device and the second electromagnetic device are configured to receive a rotational mechanical energy output from the engine and provide an electrical energy output to power a control system and/or the other electromagnetic device. In yet other embodiments, at least one of the first electromagnetic device and the second electromagnetic device are configured to receive an electrical energy input and provide a mechanical energy output to another part of the transmission (e.g., a power takeoff output). According to an exemplary embodiment, the multi-mode inline electromechanical variable transmission has a compact design that facilitates direct replacement of traditional inline transmissions (e.g., mechanical transmissions, transmissions without electromagnetic devices, etc.) used in front engine applications. Thus, the multi-mode inline electromechanical variable transmission may be installed during a new vehicle construction or installed to replace a conventional transmission of a front engine vehicle (e.g., as opposed to replacing a traditional midship transfer case, etc.). The multi-mode inline electromechanical variable transmission may additionally or alternatively be installed as part of a rear-engine vehicle (e.g., a bus, etc.). 
     According to the exemplary embodiment shown in  FIGS. 1-2 , a vehicle  10  includes an engine  20  coupled to a transmission, shown as transmission  30 . In one embodiment, engine  20  is configured to combust fuel and provide a mechanical energy input to transmission  30 . By way of example, engine  20  may be configured to provide a rotational mechanical energy input to transmission  30 . As shown in  FIGS. 1-2 , transmission  30  includes a first electrical machine, electromagnetic device, and/or motor/generator, shown as first electromagnetic device  40 , and a second electrical machine, electromagnetic device, and/or motor/generator, shown as second electromagnetic device  50 . According to an exemplary embodiment, vehicle  10  is configured as a rear engine vehicle and transmission  30  is configured as a multi-mode inline electromechanical transmission. In other embodiments, vehicle  10  is configured as a mid-engine vehicle or a front engine vehicle. 
     Referring again to the exemplary embodiment shown in  FIG. 1 , vehicle  10  includes a front axle, shown as front axle  60 , and a rear axle, shown as rear axle  70 . As shown in  FIG. 1 , front axle  60  includes a pair of tractive elements, shown as tires  62 , coupled to a front differential, shown as front differential  64 . Rear axle  70  includes a pair of tractive elements, shown as tires  72 , coupled to a rear differential, shown as rear differential  74 , according to an exemplary embodiment. According to the exemplary embodiment shown in  FIG. 1 , front differential  64  is coupled to transmission  30  with a front axle driveshaft  66 , and rear differential  74  is coupled to transmission  30  with a rear axle driveshaft  76 . While shown as coupled to tires  62  and tires  72 , front differential  64  and rear differential  74  may be coupled to various other types of tractive elements (e.g., tracks, etc.), according to alternative embodiments. As shown in  FIG. 1 , front axle driveshaft  66  and rear axle driveshaft  76  are configured to transport power from first electromagnetic device  40 , second electromagnetic device  50 , and engine  20  to tires  62  and tires  72 , respectively. Vehicle  10  may include a plurality of front differentials  64  that may be coupled and/or a plurality of rear differentials  74  that may be coupled, according to various alternative embodiments. In some embodiments, transmission  30  is selectively coupled (e.g., via a clutch mechanism, coupling mechanism, etc.) to at least one of the front axle driveshaft  66  and the rear axle driveshaft  76  (e.g., to reconfigure vehicle  10  into a front-wheel-drive configuration, a rear-wheel-drive configuration, an all-wheel-drive configuration, a four-wheel-drive configuration, etc.). 
     Engine  20  may be any source of rotational mechanical energy that is derived from a stored energy source. The stored energy source is disposed onboard vehicle  10 , according to an exemplary embodiment. The stored energy source may include a liquid fuel or a gaseous fuel, among other alternatives. In one embodiment, engine  20  includes an internal combustion engine configured to be powered by at least one of gasoline, natural gas, and diesel fuel. According to various alternative embodiments, engine  20  includes at least one of a turbine, a fuel cell, and an electric motor, or still another device. According to one exemplary embodiment, engine  20  includes a twelve liter diesel engine capable of providing between approximately 400 horsepower and approximately 600 horsepower and between approximately 400 foot pounds of torque and approximately 2000 foot pounds of torque. In one embodiment, engine  20  has a rotational speed (e.g., a rotational operational range, etc.) of between 0 and 2,100 revolutions per minute. Engine  20  may be operated at a relatively constant speed (e.g., 1,600 revolutions per minute, etc.). In one embodiment, the relatively constant speed is selected based on an operating condition of engine  20  (e.g., an operating speed relating to a point of increased fuel efficiency, etc.). 
     In one embodiment, at least one of first electromagnetic device  40  and second electromagnetic device  50  provide a mechanical energy input to another portion of transmission  30 . By way of example, at least one of first electromagnetic device  40  and second electromagnetic device  50  may be configured to provide a rotational mechanical energy input to another portion of transmission  30  (i.e., at least one of first electromagnetic device  40  and second electromagnetic device  50  may operate as a motor, etc.). At least one of first electromagnetic device  40  and second electromagnetic device  50  may receive a mechanical energy output from at least one of engine  20  and another portion of transmission  30 . By way of example, at least one of first electromagnetic device  40  and second electromagnetic device  50  may be configured to receive a rotational mechanical energy output from at least one of engine  20  and another portion of transmission  30  and provide an electrical energy output (i.e., at least one of first electromagnetic device  40  and second electromagnetic device  50  may operate as a generator, etc.). According to an exemplary embodiment, first electromagnetic device  40  and second electromagnetic device  50  are capable of both providing mechanical energy and converting a mechanical energy input into an electrical energy output (i.e., selectively operate as a motor and a generator, etc.). The operational condition of first electromagnetic device  40  and second electromagnetic device  50  (e.g., as a motor, as a generator, etc.) may vary based on a mode of operation associated with transmission  30 . 
     According to the exemplary embodiment shown in  FIG. 2 , a drive system for a vehicle, shown as drive system  100 , includes engine  20 , transmission  30 , first electromagnetic device  40 , and second electromagnetic device  50 . Transmission  30  may include first electromagnetic device  40  and second electromagnetic device  50 . As shown in  FIG. 2 , transmission  30  includes a first power transmission device or gear set, shown as power split planetary  110 , and a second power transmission device or gear set, shown as output planetary  120 . In one embodiment, power split planetary  110  and output planetary  120  are positioned outside of (e.g., on either side of, sandwiching, not between, etc.) first electromagnetic device  40  and second electromagnetic device  50 . As shown in  FIG. 2 , one or both of power split planetary  110  and output planetary  120  are disposed between (e.g., sandwiched by, etc.) first electromagnetic device  40  and second electromagnetic device  50 . 
     Referring to the exemplary embodiment shown in  FIG. 2 , power split planetary  110  is a planetary gear set that includes a sun gear  112 , a ring gear  114 , and a plurality of planetary gears  116 . The plurality of planetary gears  116  couple sun gear  112  to ring gear  114 , according to an exemplary embodiment. As shown in  FIG. 2 , a carrier  118  rotationally supports the plurality of planetary gears  116 . A clutch, shown as neutral clutch  22 , is positioned to selectively couple first electromagnetic device  40  to sun gear  112 . Neutral clutch  22  may be a component of first electromagnetic device  40  or transmission  30  or a separate component. Accordingly, first electromagnetic device  40  is selectively coupled to sun gear  112  such that power split planetary  110  is selectively coupled to first electromagnetic device  40 . By way of example, first electromagnetic device  40  may include or be coupled to a shaft (e.g., a first shaft, an input shaft, an output shaft, etc.) selectively coupled to sun gear  112 . According to an alternative embodiment, neutral clutch  22  is omitted, and first electromagnetic device  40  is directly coupled to sun gear  112 . 
     Referring still to the exemplary embodiment shown in  FIG. 2 , output planetary  120  is a planetary gear set that includes a sun gear  122 , a ring gear  124 , and a plurality of planetary gears  126 . The plurality of planetary gears  126  couple sun gear  122  to ring gear  124 , according to an exemplary embodiment. As shown in  FIG. 2 , a carrier  128  rotationally supports the plurality of planetary gears  126 . In one embodiment, second electromagnetic device  50  is directly coupled to sun gear  122  such that output planetary  120  is coupled to second electromagnetic device  50 . By way of example, second electromagnetic device  50  may include or be coupled to a shaft (e.g., a second shaft, an input shaft, an output shaft, etc.) directly coupled to sun gear  122 . Carrier  118  is directly coupled to carrier  128 , thereby coupling power split planetary  110  to output planetary  120 , according to the exemplary embodiment shown in  FIG. 2 . In one embodiment, directly coupling carrier  118  to carrier  128  synchronizes the rotational speeds of carrier  118  and carrier  128 . 
     Carrier  118  is directly rotationally coupled to an output with a shaft, shown as output shaft  32 , according to the exemplary embodiment shown in  FIG. 2 . Output shaft  32  may be coupled to at least one of rear axle driveshaft  76  and front axle driveshaft  66 . By way of example, output shaft  32  may be coupled to a transfer case and/or rear axle driveshaft  76  where transmission  30  is installed in place of a traditional, mechanical, straight-thru transmission. In another embodiment, the output is a PTO output, and output shaft  32  is coupled thereto. A clutch assembly may be engaged and disengaged to selectively couple at least one of front axle driveshaft  66 , a transfer case, and rear axle driveshaft  76  to output shaft  32  of transmission  30  (e.g., to facilitate operation of a vehicle in a rear-wheel-drive mode, an all-wheel-drive mode, a four-wheel-drive mode, a front-wheel-drive mode, etc.). As shown in  FIG. 2 , the transmission  30  includes an auxiliary shaft, shown as jack shaft  34 . In some embodiments, jack shaft  34  is offset (e.g., radially offset) from first electromagnetic device  40 , second electromagnetic device  50 , power split planetary  110 , and/or output planetary  120 . As shown in  FIG. 2 , transmission  30  includes a shaft, shown as connecting shaft  36 , directly coupled to engine  20 . According to an exemplary embodiment, connecting shaft  36  directly couples engine  20  to power split planetary  110 . In one embodiment, connecting shaft  36  directly couples engine  20  with ring gear  114  of power split planetary  110 . According to an exemplary embodiment, power split planetary  110  is at least one of directly coupled to and directly powers a power takeoff (“PTO”) (e.g., a live PTO, etc.). By way of example, ring gear  114  and/or carrier  118  of power split planetary  110  may be at least one of directly coupled to and directly power the PTO. 
     As shown in  FIG. 2 , transmission  30  includes a first clutch, shown as input coupled clutch  140 . Input coupled clutch  140  is positioned to selectively couple second electromagnetic device  50  with engine  20 , according to an exemplary embodiment. Input coupled clutch  140  may thereby selectively couple engine  20  to output planetary  120 . As shown in  FIG. 2 , connecting shaft  36  extends from engine  20 , through input coupled clutch  140  and second electromagnetic device  50 , and through output planetary  120  to power split planetary  110 . Input coupled clutch  140  may selectively couple second electromagnetic device  50  with connecting shaft  36 . Accordingly, input coupled clutch  140  may selectively couple connecting shaft  36  to sun gear  122  of output planetary  120 . According to an exemplary embodiment, first electromagnetic device  40  and second electromagnetic device  50  (e.g., input/output shafts thereof, etc.) are aligned (e.g., radially aligned, etc.) with power split planetary  110 , output planetary  120 , connecting shaft  36 , and/or output shaft  32  (e.g., centerlines thereof are aligned, to thereby form a straight-thru or inline transmission arrangement, etc.). 
     Jack shaft  34  is rotationally coupled to carrier  118  of power split planetary  110  and thereby to output shaft  32 . According to the exemplary embodiment shown in  FIG. 2 , transmission  30  further includes a second clutch, shown as output coupled clutch  150 . Output coupled clutch  150  is positioned to selectively couple jackshaft  34  to ring gear  124  of output planetary  120 . In some embodiments, jack shaft  34  is rotationally coupled (e.g., selectively rotationally coupled, etc.) to one or more outputs, shown as PTO outputs  80  (e.g., to drive one or more hydraulic pumps, to power one or more hydraulic systems, to power one or more electrical power generation systems, to power one or more pneumatic systems, etc.). In other embodiments, the one or more outputs are used to power (e.g., drive, etc.) a vehicle with which transmission  30  is associated. 
     Transmission  30  may further include a third clutch, shown in  FIG. 2  as secondary output clutch  42 . In other embodiments, secondary output clutch  42  is omitted. Secondary output clutch  42  is positioned to selectively couple first electromagnetic device  40  with an additional PTO output  80 , according to an exemplary embodiment. Like the PTO outputs  80  rotationally coupled to the jackshaft  34 , the PTO output  80  coupled to the secondary output clutch  42  may be configured to drive one or more hydraulic pumps, to power one or more hydraulic systems, to power one or more electrical power generation systems, to power one or more pneumatic systems, or to power another type of system. In other embodiments, the output is used to power (e.g., drive, etc.) a vehicle with which transmission  30  is associated. Secondary output clutch  42  may thereby selectively couple this PTO output  80  to sun gear  112  of power split planetary  110  when neutral clutch  22  is engaged. The PTO output  80  may be directly coupled to the secondary output clutch  42  (e.g., arranged concentrically or in line with the secondary output clutch  42  and the first electromagnetic device  40 , including gear teeth in meshing engagement with the secondary output clutch  42 , etc.) or indirectly coupled to the secondary output clutch  42  (e.g., using a gear train, using a pulley and belt arrangement, using a chain and sprocket arrangement, etc.). As shown in  FIG. 2 , output shaft  32  extends from power split planetary  110 , through first electromagnetic device  40 , and out through secondary output clutch  42 . 
     In some embodiments, neutral clutch  22  is biased into an engaged position (e.g., with a spring, etc.) and selectively disengaged (e.g., with application of pressurized hydraulic fluid, etc.). In some embodiments, input coupled clutch  140  is biased into a disengaged position (e.g., with a spring, etc.) and selectively engaged (e.g., with application of pressurized hydraulic fluid, etc.). In some embodiments, output coupled clutch  150  is biased into a disengaged position (e.g., with a spring, etc.) and selectively engaged (e.g., with application of pressurized hydraulic fluid, etc.). In some embodiments, secondary output clutch  42  is biased into a disengaged position (e.g., with a spring, etc.) and selectively engaged (e.g., with application of pressurized hydraulic fluid, etc.). In other embodiments, one or more of neutral clutch  22 , input coupled clutch  140 , output coupled clutch  150 , and secondary output clutch  42  are hydraulically-biased and spring released. 
     Referring again to the exemplary embodiment shown in  FIG. 2 , transmission  30  includes a brake, shown as output brake  170 . Output brake  170  is positioned to selectively inhibit the movement of at least a portion of output planetary  120  (e.g., ring gear  124 , etc.), according to an exemplary embodiment. In one embodiment, output brake  170  is biased into a disengaged position (e.g., with a spring, etc.) and selectively engaged (e.g., with application of pressurized hydraulic fluid, etc.). In other embodiments, output brake  170  is hydraulically-biased and spring released. In still other embodiments, the components of transmission  30  are still otherwise engaged and disengaged (e.g., pneumatically, etc.). By way of example, output brake  170  and output coupled clutch  150  may be engaged simultaneously, providing a driveline brake such that rotational movement of at least one of output planetary  120  (e.g., ring gear  124 , etc.), power split planetary  110  (e.g., carrier  118 , etc.), jack shaft  34 , and output shaft  32  are selectively limited. 
     As shown in  FIG. 2 , transmission  30  includes a gear set  180  that couples carrier  118  and carrier  128  to jack shaft  34 . In one embodiment, gear set  180  includes a first gear, shown as gear  182 , in meshing engagement with a second gear, shown as gear  184 . As shown in  FIG. 2 , gear  182  is rotatably coupled to carrier  118  and carrier  128 . By way of example, gear  182  may be fixed to a component (e.g., shaft, tube, etc.) that couples carrier  118  and carrier  128 . As shown in  FIG. 2 , gear  184  is rotatably coupled to jack shaft  34 . By way of example, gear  184  may be fixed directly to the jack shaft  34 . 
     According to an exemplary embodiment, transmission  30  includes a gear set, shown as gear set  190 , that couples output planetary  120  to jack shaft  34 . As shown in  FIG. 2 , gear set  190  includes a first gear, shown as gear  192 , coupled to ring gear  124  of output planetary  120 . Gear  192  is in meshing engagement with a second gear, shown as gear  194 , according to an exemplary embodiment. As shown in  FIG. 2 , gear  194  is coupled to a third gear, shown as gear  196 . Gear  194  may reverse the rotation direction of an output provided by gear  192  (e.g., gear  194  may facilitate rotating jack shaft  34  in the same direction as that of gear  192 , etc.). In other embodiments, gear  192  is directly coupled with gear  196 . By way of example, gear set  190  may not include gear  194 , and gear  192  may be directly coupled to (e.g., in meshing engagement with, etc.) gear  196 . As shown in  FIG. 2 , output coupled clutch  150  is positioned to selectively couple gear  196  with output shaft  32  when engaged. With output coupled clutch  150  disengaged, relative movement (e.g., rotation, etc.) may occur between gear  196  and jack shaft  34 . By way of example, output coupled clutch  150  may be engaged to couple ring gear  124  to jack shaft  34 . Output brake  170  is positioned to selectively limit the movement of gear  192  when engaged to thereby also limit the movement of ring gear  124 , gear  194 , and gear  196 . 
     According to the exemplary embodiment shown in  FIG. 3 , a control system  200  for a vehicle (e.g., vehicle  10 , etc.) includes a controller  210 . In one embodiment, controller  210  is configured to selectively engage, selectively disengage, or otherwise communicate with components of the vehicle according to various modes of operation. As shown in  FIG. 3 , controller  210  is coupled to engine  20 . In one embodiment, controller  210  is configured to selectively engage engine  20  (e.g., interface with a throttle thereof, etc.) such that an output of engine  20  rotates at a target rate. Controller  210  is coupled to first electromagnetic device  40  and second electromagnetic device  50 , according to an exemplary embodiment, and may send and receive signals therewith. By way of example, controller  210  may send command signals relating to at least one of a target mode of operation, a target rotational speed, and a target rotation direction for first electromagnetic device  40  and second electromagnetic device  50 . As shown in  FIG. 3 , first electromagnetic device  40  and second electromagnetic device  50  are electrically coupled (e.g., by an electrical power transmission system, etc.). By way of example, power generated by first electromagnetic device  40  may be utilized by second electromagnetic device  50  (e.g., to provide an output torque as a motor, etc.), or power generated by second electromagnetic device  50  may be utilized by first electromagnetic device  40  (e.g., to provide an output torque as a motor, etc.). Controller  210  is configured to selectively engage and selectively disengage neutral clutch  22 , secondary output clutch  42 , input coupled clutch  140 , output coupled clutch  150 , and output brake  170  directly or by interacting with another component (e.g., a pump, a valve, a solenoid, a motor, etc.). 
     According to an exemplary embodiment, the drive system  100  includes an energy storage device (e.g., a battery, etc.). In such embodiments, the battery may be charged and recharged by an electromagnetic device that is generating power. The battery may supply the electromagnetic device that is motoring the vehicle to at least one of propel the vehicle and operate a PTO output  80 . In some embodiments, the battery may always be utilized as part of the drive system  100 . In other embodiments, the battery may be used only when excess generated power must be stored or excess power is required to motor the vehicle. 
     According to alternative embodiments, drive system  100  may be configured to operate with first electromagnetic device  40  and second electromagnetic device  50 , and no additional sources of electrical power. Additional sources of electrical power include, for example, a battery and other energy storage devices. Without an energy storage device, first electromagnetic device  40  and second electromagnetic device  50  may operate in power balance. One of the electromagnetic devices may provide all of the electrical power required by the other electromagnetic device (as well as the electrical power required to offset power losses). First electromagnetic device  40  and second electromagnetic device  50  may operate without doing either of (a) providing electrical power to an energy storage device or (b) consuming electrical power from an energy storage device. Thus, the sum of the electrical power produced or consumed by first electromagnetic device  40 , the electrical power produced or consumed by second electromagnetic device  50 , and electrical power losses may be zero. According to the embodiment of  FIGS. 1-3 , two electromagnetic devices are shown. In other embodiments, the system includes three or more electromagnetic devices. 
     According to the exemplary embodiment shown in  FIG. 3 , control system  200  includes a user interface  220  that is coupled to controller  210 . In one embodiment, user interface  220  includes a display and an operator input. The display may be configured to display a graphical user interface, an image, an icon, or still other information. In one embodiment, the display includes a graphical user interface configured to provide general information about the vehicle (e.g., vehicle speed, fuel level, warning lights, etc.). The graphical user interface may be configured to also display a current mode of operation, various potential modes of operation, or still other information relating to transmission  30  and/or drive system  100 . By way of example, the graphical user interface may be configured to provide specific information regarding the operation of drive system  100  (e.g., whether neutral clutch  22 , secondary output clutch  42 , input coupled clutch  140 , output coupled clutch  150 , and/or output brake  170  are engaged or disengaged, a fault condition where at least one of neutral clutch  22 , secondary output clutch  42 , input coupled clutch  140 , output coupled clutch  150 , and/or output brake  170  fail to engage or disengage in response to a command signal, etc.). 
     The operator input may be used by an operator to provide commands to at least one of engine  20 , transmission  30 , first electromagnetic device  40 , second electromagnetic device  50 , and drive system  100  or still another component of the vehicle. The operator input may include one or more buttons, knobs, touchscreens, switches, levers, or handles. In one embodiment, an operator may press a button to change the mode of operation for at least one of transmission  30 , and drive system  100 , and the vehicle. The operator may be able to manually control some or all aspects of the operation of transmission  30  using the display and the operator input. It should be understood that any type of display or input controls may be implemented with the systems and methods described herein. 
     Controller  210  may be implemented as a general-purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a digital-signal-processor (DSP), circuits containing one or more processing components, circuitry for supporting a microprocessor, a group of processing components, or other suitable electronic processing components. According to the exemplary embodiment shown in  FIG. 3 , controller  210  includes a processing circuit  212  and a memory  214 . Processing circuit  212  may include an ASIC, one or more FPGAs, a DSP, circuits containing one or more processing components, circuitry for supporting a microprocessor, a group of processing components, or other suitable electronic processing components. In some embodiments, processing circuit  212  is configured to execute computer code stored in memory  214  to facilitate the activities described herein. Memory  214  may be any volatile or non-volatile computer-readable storage medium capable of storing data or computer code relating to the activities described herein. According to an exemplary embodiment, memory  214  includes computer code modules (e.g., executable code, object code, source code, script code, machine code, etc.) configured for execution by processing circuit  212 . Memory  214  includes various actuation profiles corresponding to modes of operation (e.g., for transmission  30 , for drive system  100 , for a vehicle, etc.), according to an exemplary embodiment. In some embodiments, controller  210  may represent a collection of processing devices (e.g., servers, data centers, etc.). In such cases, processing circuit  212  represents the collective processors of the devices, and memory  214  represents the collective storage devices of the devices. 
     Referring next to the exemplary embodiments shown in  FIGS. 4-13 , transmission  30  is configured to operate according to a plurality of modes of operation. Various modes of operation for transmission  30  are identified below in Table 1. In other embodiments, a vehicle having transmission  30  is configured to operate according to the various modes of operation shown in  FIGS. 4-13  and identified below in Table 1. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Output  
                   
                 Input  
                 Secondary  
               
               
                   
                 Neutral  
                 Coupled  
                 Output  
                 Coupled  
                 Output  
               
               
                 Mode of  
                 Clutch  
                 Clutch  
                 Brake  
                 Clutch  
                 Clutch  
               
               
                 Operation 
                 22 
                 150 
                 170 
                 140 
                 42 
               
               
                   
               
             
            
               
                 Mid Speed  
                 X 
                   
                 X 
                   
                   
               
               
                 Reverse 
                   
                   
                   
                   
                   
               
               
                 Low Speed  
                 X 
                 X 
                   
                   
                   
               
               
                 Reverse 
                   
                   
                   
                   
                   
               
               
                 Power  
                 X 
                   
                   
                 X 
                   
               
               
                 Generation 
                   
                   
                   
                   
                   
               
               
                 Neutral/Vehicle  
                 X 
                 X 
                 X 
                   
                   
               
               
                 Start 
                   
                   
                   
                   
                   
               
               
                 Low Range 
                 X 
                 X 
                   
                   
                   
               
               
                 Mid Range 
                 X 
                   
                 X 
                   
                   
               
               
                 Shift 
                 X 
                   
                 X 
                 X 
                   
               
               
                 High Range 
                 X 
                   
                   
                 X 
                   
               
               
                 Electric PTO 
                   
                   
                   
                   
                 X 
               
               
                   
               
            
           
         
       
     
     As shown in Table 1, an “X” represents a component of drive system  100  (e.g., output brake  170 , input coupled clutch  140 , etc.) that is engaged or closed during the respective modes of operation. 
     In each of the modes shown in  FIGS. 4-12 , neutral clutch  22  is engaged. When engaged, neutral clutch  22  couples first electromagnetic device  40  to sun gear  112 . When disengaged, neutral clutch  22  decouples first electromagnetic device  40  from sun gear  112 . Accordingly, neutral clutch  22  may be used to isolate first electromagnetic device  40 , secondary output clutch  42 , and the PTO output  80  coupled to secondary output clutch  42  from transmission  30 . With neutral clutch  22  disengaged, first electromagnetic device  40  may be used to drive the PTO output  80  coupled to the secondary output clutch  42  independent of engine  20  (e.g., without engine  20  running) and transmission  30  (e.g., without moving sun gear  112 ). 
     As shown in  FIGS. 4 and 5 , transmission  30  is selectively reconfigured into neutral/startup modes. The neutral/startup mode may provide a true neutral for transmission  30 . In one embodiment, at least one of first electromagnetic device  40  and second electromagnetic device  50  include and/or are coupled to an energy storage device (e.g., a capacitor, a battery, etc.) configured to store energy (e.g., electrical energy, chemical energy, etc.) associated with drive system  100 . In one embodiment, rotation of first electromagnetic device  40  rotates connecting shaft  36  to start engine  20  (e.g., with neutral clutch  22 , output coupled clutch  150 , and output brake  170  engaged, etc.). In another embodiment, rotation of second electromagnetic device  50  rotates connecting shaft  36  to start engine  20  (e.g., with neutral clutch  22  and input coupled clutch  140  engaged, etc.). First electromagnetic device  40  or second electromagnetic device  50  may be configured to use the stored energy to start engine  20  by providing a rotational mechanical energy input (e.g., a torque, etc.) to engine  20  through connecting shaft  36 . 
     In an alternative embodiment, engine  20  includes a traditional starting mechanism (e.g., a starter motor, etc.) configured to start engine  20  (e.g., in response to a vehicle start request, in response to an engine start request, etc.). The vehicle start request and/or the engine start request may include a directive to turn the engine “on” from an “off” state. The vehicle may include at least one of a pushbutton, a graphical user interface, an ignition, and another device with which a user interacts to provide or trigger the vehicle start request and/or the engine start request. Engine  20  may provide a rotational mechanical energy input to at least one of first electromagnetic device  40  and/or second electromagnetic device  50 . First electromagnetic device  40  and second electromagnetic device  50  may be brought up to a threshold (e.g., a threshold speed, a threshold speed for a target period of time, a threshold power generation, a threshold power generation for a target period of time, etc.) that establishes a requisite DC bus voltage for controlling first electromagnetic device  40  and/or second electromagnetic device  50 . Both first electromagnetic device  40  and second electromagnetic device  50  may thereafter be activated and controlled within and/or to desired states. The power electronics of control system  200  that control the motor-to-motor functions may be brought online during the neutral/startup mode. 
     As shown in  FIG. 4  and Table 1, neutral clutch  22 , output coupled clutch  150 , and output brake  170  are engaged when transmission  30  is configured in the neutral/startup mode. According to an exemplary embodiment, engaging neutral clutch  22 , output brake  170 , and output coupled clutch  150  selectively limits the rotational movement of portions of both power split planetary  110  and output planetary  120 . By way of example, engaging output brake  170  may inhibit the rotational movement of ring gear  124 , gear  192 , gear  194 , and gear  196  such that each remains rotationally fixed. Engaging output coupled clutch  150  may inhibit rotational movement of jack shaft  34  such that jack shaft  34  remains rotationally fixed (e.g., since gear  196  is fixed and output coupled clutch  150  is engaged, etc.). With jack shaft  34  rotationally fixed, gear set  180  and carrier  118  become rotationally fixed, thereby isolating output shaft  32  from engine  20 , first electromagnetic device  40 , and second electromagnetic device  50  in the neutral/startup mode. Such isolation may substantially eliminate a forward lurch potential of the vehicle during startup (e.g., transmission  30  does not provide an output torque to tires  62  and/or tires  72 , etc.). Alternatively, as shown in  FIG. 5 , output coupled clutch  150  may be disengaged (e.g., before startup, during startup, after startup, etc.). However, disengaging output coupled clutch  150  may not prevent rotation of the jack shaft  34  and thereby output shaft  32 . 
     According to an exemplary embodiment, an energy flow path in the neutral/startup mode includes: first electromagnetic device  40  providing a rotational mechanical energy input to sun gear  112  through neutral clutch  22  that is received by the plurality of planetary gears  116 ; the plurality of planetary gears  116  rotating about central axes thereof (e.g., planetary gears  116  may not rotate about sun gear  112  because carrier  118  may be rotationally fixed, etc.); the plurality of planetary gears  116  conveying the rotational mechanical energy to ring gear  114 ; ring gear  114  transferring the rotational mechanical energy to the engine  20  through the connecting shaft  36  such that the rotational mechanical energy provided by first electromagnetic device  40  starts engine  20 . 
     An alternative energy flow path in the neutral/startup mode may include starting engine  20  with a traditional starting mechanism, engine  20  providing a rotational mechanical energy input to ring gear  114  that is received by the plurality of planetary gears  116 ; the plurality of planetary gears  116  rotating about central axes thereof (e.g., planetary gears  116  may or may not rotate about sun gear  112  because carrier  118  may or may not be rotationally fixed, etc.); the plurality of planetary gears  116  conveying the rotational mechanical energy to sun gear  112 ; and sun gear  112  conveying the rotational mechanical energy to first electromagnetic device  40  through neutral clutch  22  to bring first electromagnetic device  40  up to the threshold for establishing a requisite DC bus voltage and controlling first electromagnetic device  40  and/or second electromagnetic device  50  in a desired state. By way of example, the neutral/startup mode may be used to start engine  20 , establish a requisite DC bus voltage, or otherwise export power without relying on controller  210  to engage first electromagnetic device  40  and/or second electromagnetic device  50 . Transmission  30  may provide increased export power potential relative to traditional transmission systems. 
     As shown in  FIG. 6 , transmission  30  is selectively reconfigured into a low range mode of operation such that transmission  30  allows for a low output speed operation with a high output torque (e.g., in a forward direction of travel, etc.). The low range mode increases a vehicle&#39;s gradability (e.g., facilitates the vehicle maintaining speed on a grade, etc.). In one embodiment, engine  20  provides a rotational mechanical energy input to transmission  30  such that first electromagnetic device  40  generates electrical power and second electromagnetic device  50  uses the generated electrical power to provide a rotational mechanical energy output. As such, at least one of engine  20  and second electromagnetic device  50  provide a rotational mechanical energy input to drive at least one of tires  62  and tires  72 . In an alternative embodiment, first electromagnetic device  40  operates as a motor and second electromagnetic device  50  operates as a generator when transmission  30  is configured in the low range forward mode. In still another alternative embodiment, both first electromagnetic device  40  and second electromagnetic device  50  operate as a generator in the low range forward mode. In yet another embodiment, transmission  30  is not selectively reconfigurable into the low range mode of operation. In one such embodiment, transmission  30  does not include jack shaft  34 , does not include gear set  190  (e.g., gear  192 , gear  194 , gear  196 , etc.), and does not include output coupled clutch  150 . Transmission  30  may additionally or alternatively not include gear set  180  in embodiments where transmission  30  is not selectively reconfigurable into the low range mode of operation. 
     As shown in  FIG. 6  and Table 1, neutral clutch  22  and output coupled clutch  150  are engaged when transmission  30  is configured in the low range mode. As shown in  FIG. 6 , output coupled clutch  150  couples gear set  190  to jack shaft  34 . Accordingly, when engine  20  provides a rotational mechanical energy input to transmission  30 , at least one of engine  20  and second electromagnetic device  50  drive output shaft  32  through the interaction of connecting shaft  36  and jack shaft  34  with power split planetary  110 , respectively. According to the exemplary embodiment shown in  FIG. 6 , an energy flow path for the low range includes: engine  20  providing a rotational mechanical energy input to connecting shaft  36 ; connecting shaft  36  conveying the rotational mechanical energy to ring gear  114 ; ring gear  114  causing the plurality of planetary gears  116  to rotate about central axes thereof, as well as about sun gear  112  such that carrier  118  and output shaft  32  rotate; and the rotation of the plurality of planetary gears  116  about a central axis causing a rotation of sun gear  112 , thus driving first electromagnetic device  40  through neutral clutch  22  such that first electromagnetic device  40  operates as a generator (e.g., generates electrical energy, etc.). 
     Referring still to  FIG. 6 , the rotation of carrier  118  drives both carrier  128  and gear set  180 . Carrier  128  drives the plurality of planetary gears  126  to rotate about sun gear  122  and about central axes thereof. In one embodiment, second electromagnetic device  50  receives electrical energy generated by first electromagnetic device  40 . Accordingly, second electromagnetic device  50  operates as a motor, providing a rotational mechanical energy input to sun gear  122 . The sun gear  122  conveys the rotational mechanical energy to the plurality of planetary gears  126  such that each further rotates about the central axis thereof. The plurality of planetary gears  126  drive ring gear  124 , and the rotation of ring gear  124  drives gear set  190 . According to the exemplary embodiment shown in  FIG. 6 , gear set  180  and gear set  190  transfer a torque to and from jack shaft  34  with output coupled clutch  150  engaged. As such, engine  20  and second electromagnetic device  50  move a vehicle at a low speed with a high output torque. 
     As shown in  FIG. 7 , transmission  30  is selectively reconfigured into a mid range mode of operation. In the mid range mode of operation, transmission  30  may facilitate a mid range output speed operation (e.g., in a forward direction of travel, etc.). The speed range associated with the mid range mode of operation may be larger than that of traditional transmissions (i.e., transmission  30  may provide increased coverage in the mid range, etc.). The mid range mode may improve low output speed torque and high output speed power. In one embodiment, engine  20  provides a rotational mechanical energy input such that first electromagnetic device  40  generates electrical power, and second electromagnetic device  50  uses the generated electrical power to provide a rotational mechanical energy output. Second electromagnetic device  50  thereby provides a rotational mechanical energy input to drive at least one of tires  62  and tires  72 . In an alternative embodiment, second electromagnetic device  50  operates as a generator while first electromagnetic device  40  operates as a motor when transmission  30  is configured in the mid range mode. In still another alternative embodiment, both first electromagnetic device  40  and second electromagnetic device  50  operate as a generator in the mid range mode. 
     As shown in  FIG. 7  and Table 1, neutral clutch  22  and output brake  170  are engaged when transmission  30  is configured in the mid range mode. As shown in  FIG. 7 , output brake  170  inhibits the rotation of gear set  190  (e.g., gear  192 , gear  194 , gear  196 , etc.). Output brake  170  thereby rotationally fixes ring gear  124 . In one embodiment, engaging output brake  170  substantially eliminates a power dip between output and input modes of transmission  30 . According to the exemplary embodiment shown in  FIG. 7 , an energy flow path for the mid range forward mode includes: engine  20  providing a rotational mechanical energy input to connecting shaft  36  that is conveyed to ring gear  114 ; ring gear  114  driving the plurality of planetary gears  116  to rotate about central axes thereof, as well as about sun gear  112  such that both carrier  118  and sun gear  112  rotate; and the rotation of carrier  118  driving the output shaft  32 . 
     With ring gear  124  fixed by output brake  170 , second electromagnetic device  50  may operate as a motor. In one embodiment, second electromagnetic device  50  receives electrical energy generated by first electromagnetic device  40 . First electromagnetic device  40  operates as a generator, removing a rotational mechanical energy from sun gear  112  through neutral clutch  22 . The sun gear  122  conveys rotational mechanical torque from the second electromagnetic device  50  to the plurality of planetary gears  126  such that each further rotates about sun gear  122  (e.g., at an increased rotational speed, etc.). The rotation of the plurality of planetary gears  126  (e.g., effected by sun gear  122 , etc.) drives carrier  128  and thereby carrier  118 . Carrier  118  drives output shaft  32  at a mid range output speed and may thereby drive a vehicle at a mid range output speed. 
     As shown in  FIG. 8 , transmission  30  is selectively reconfigured into a high range mode of operation such that transmission  30  allows for a high output speed operation (e.g., in a forward direction of travel, etc.). In one embodiment, engine  20  provides a rotational mechanical energy input such that second electromagnetic device  50  generates electrical power while first electromagnetic device  40  uses the generated electrical power to provide a rotational mechanical energy output. As such, at least one of engine  20  and first electromagnetic device  40  provide rotational mechanical energy to drive at least one of tires  62  and tires  72 . In an alternative embodiment, first electromagnetic device  40  operates as a generator and second electromagnetic device  50  operates as a motor when transmission  30  is configured in the high range mode. 
     As shown in  FIG. 8  and Table 1, neutral clutch  22  and input coupled clutch  140  are engaged when transmission  30  is configured in the high range mode. As shown in  FIG. 8 , the engagement of input coupled clutch  140  with connecting shaft  36  rotationally couples engine  20  and second electromagnetic device  50 . By way of example, engine  20  may provide a rotational mechanical energy input to connecting shaft  36  such that second electromagnetic device  50  generates electrical energy. In one embodiment, first electromagnetic device  40  receives the electrical energy generated by second electromagnetic device  50 . First electromagnetic device  40  operates as a motor, providing a rotational mechanical energy input to sun gear  112  through neutral clutch  22  that drives the plurality of planetary gears  116  and carrier  118 . 
     Referring still to  FIG. 8 , power from engine  20  is transferred to ring gear  114  and the plurality of planetary gears  116 . The plurality of planetary gears  116  are driven by at least one of engine  20  (e.g., via ring gear  114 , etc.) and first electromagnetic device  40  (e.g., via sun gear  112 , etc.). Carrier  118  rotates, which drives output shaft  32  such that the rotational mechanical energy provided by engine  20  and first electromagnetic device  40  drives a vehicle at a high range speed. 
     As shown in  FIG. 9 , transmission  30  is selectively reconfigured into an intermediate shift mode of operation that facilitates transitioning transmission  30  (i.e., shifting, changing modes, etc.) between the mid range mode of operation and the high range mode of operation. According to the embodiment shown in  FIG. 9 , neutral clutch  22 , input coupled clutch  140 , and output brake  170  are engaged when transmission  30  is selectively reconfigured into the intermediate shift mode of operation. According to an exemplary embodiment, the intermediate shift mode provides a smooth and robust shifting strategy that functions reliably even in a wide variety of operating conditions, when using various types of oil for the components of transmission  30 , and when experiencing valve nonlinearities that may be present in one or more valves of transmission  30 . The intermediate shift mode may provide a zero inertia shift through and across two or more overlapping ranges (e.g., the mid range and the high range, etc.). According to the exemplary embodiment shown in  FIGS. 7-9 , the intermediate shift mode eliminates the need to simultaneously disengage output brake  170  and engage input coupled clutch  140  to shift from the mid range mode to the high range mode, or vice versa. The intermediate shift mode reduces jerking sensations associated with simultaneously disengaging output brake  170  and engaging input coupled clutch  140  to shift from mid range to high range, providing a smoother ride. 
     During operation, the intermediate shift mode may be used to shift from mid range mode to high range mode or from high range mode to mid range mode. In one embodiment, when shifting between the mid range mode and the high range mode, both input coupled clutch  140  and output brake  170  are engaged for a period of time prior to disengaging input coupled clutch  140  or output brake  170 . Transmission  30  may be selectively reconfigured into the intermediate shift mode in response to one or more inputs reaching a predetermined threshold condition, the inputs including a rotational speed of second electromagnetic device  50  and a rotational speed of connecting shaft  36  and/or engine  20 . One or more sensors may be positioned to monitor the rotational speed of at least one of engine  20 , connecting shaft  36 , a portion of second electromagnetic device  50 , or still another component. A controller (e.g., controller  210 , etc.) may reconfigure transmission  30  into the intermediate shift mode in response to sensing signals provided by the one or more sensors. 
     As shown in  FIG. 10 , transmission  30  is selectively reconfigured into a low speed reverse mode of operation. In one embodiment, engine  20  provides a rotational mechanical energy input to transmission  30  such that first electromagnetic device  40  generates electrical power and second electromagnetic device  50  uses the generated electrical power to provide a rotational mechanical energy input to transmission  30 . As such, at least one of engine  20  and second electromagnetic device  50  provide rotational mechanical energy to drive at least one of tires  62  and tires  72  in a reverse direction (e.g., backwards, etc.). In an alternative embodiment, first electromagnetic device  40  operates as a motor and second electromagnetic device  50  operates as a generator when transmission  30  is configured in the low range reverse mode. 
     As shown in  FIG. 10  and Table 1, neutral clutch  22  and output coupled clutch  150  are engaged when transmission  30  is configured in the low speed reverse mode. As shown in FIG.  10 , the low speed reverse mode is substantially similar to the low range mode of  FIG. 6  in that output coupled clutch  150  couples gear set  190  to output shaft  32 . In the low speed reverse mode, second electromagnetic device  50  may provide a rotational mechanical energy input to transmission  30  in an opposite direction as compared to the low range mode of  FIG. 6 . 
     As shown in  FIG. 11 , transmission  30  is selectively reconfigured into a mid speed reverse mode of operation such that transmission  30  allows for a mid reverse output speed operation. In one embodiment, engine  20  provides a rotational mechanical energy input such that first electromagnetic device  40  generates electrical power, and second electromagnetic device  50  uses the generated electrical power to provide a rotational mechanical energy input to transmission  30 . As such, at least one of engine  20  and second electromagnetic device  50  provides a rotational mechanical energy input to drive at least one of tires  62  and tires  72  in a reverse direction (e.g., backwards). In an alternative embodiment, second electromagnetic device  50  operates as a generator and first electromagnetic device  40  operates as a motor when transmission  30  is configured in the mid speed reverse mode. In still another alternative embodiment, both first electromagnetic device  40  and second electromagnetic device  50  operate as a generator in the mid speed reverse mode. 
     As shown in  FIG. 11  and Table 1, neutral clutch  22  and output brake  170  are engaged when transmission  30  is configured in the mid speed reverse mode. As shown in  FIG. 11 , output brake  170  inhibits the rotation of gear set  190  (e.g., gear  192 , gear  194 , gear  196 , etc.). Output brake  170  thereby rotationally fixes ring gear  124 . According to the exemplary embodiment shown in  FIG. 11 , an energy flow path for the mid speed reverse mode includes: engine  20  providing a rotational mechanical energy input to connecting shaft  36  that is conveyed to ring gear  114 ; and ring gear  114  driving the plurality of planetary gears  116  to rotate about central axes thereof, as well as about sun gear  112  such that both carrier  118  and sun gear  112  rotate. 
     Referring still to  FIG. 11 , the rotation of carrier  118  drives carrier  128 , which rotates the plurality of planetary gears  126  about central axes thereof, as well as about sun gear  122 . With ring gear  124  fixed by output brake  170 , second electromagnetic device  50  may operate as a motor. In one embodiment, second electromagnetic device  50  receives electrical energy generated by first electromagnetic device  40 . Accordingly, first electromagnetic device  40  operates as a generator, removing a rotational mechanical energy from sun gear  112  through neutral clutch  22 . Second electromagnetic device  50  receives electrical energy from first electromagnetic device  40 , applying a rotational mechanical torque to sun gear  122 . The sun gear  122  conveys the rotational mechanical torque to the plurality of planetary gears  126  such that each further rotates about sun gear  122  (e.g., at an increased rotational speed, etc.). The rotation of the plurality of planetary gears  126  (e.g., effected by sun gear  122 , etc.) drives carrier  128  and thereby carrier  118 . Carrier  118  drives output shaft  32  at a mid reverse output speed and may thereby drive a vehicle at a mid reverse output speed. 
     As shown in  FIG. 12 , transmission  30  is selectively reconfigured into a power generation mode such that rotation of connecting shaft  36  rotates first electromagnetic device  40  and second electromagnetic device  50  to generate electrical power. In one embodiment, the electrical power is stored for future use. In another embodiment, the electrical power is used to power internal devices (e.g., control system  200 , components of the vehicle, etc.) and/or external devices. As shown in  FIG. 12  and Table 1, neutral clutch  22  and input coupled clutch  140  are engaged when transmission  30  is configured in the power generation mode. 
     According to an exemplary embodiment, engine  20  provides a rotational mechanical energy input to connecting shaft  36 , which drives both first electromagnetic device  40  and second electromagnetic device  50 . As shown in  FIG. 12 , second electromagnetic device  50  is rotationally coupled to engine  20  via the engagement of input coupled clutch  140  with connecting shaft  36  such that second electromagnetic device  50  generates electrical power. According to the exemplary embodiment shown in  FIG. 12 , an energy flow path for the power generation mode includes: connecting shaft  36  provides rotational mechanical energy to ring gear  114  of power split planetary  110 ; ring gear  114  conveys the rotational mechanical energy from connecting shaft  36  to the plurality of planetary gears  116 ; the plurality of planetary gears  116  rotate about central axes thereof, thereby transferring rotational mechanical energy to sun gear  112 ; sun gear  112  provides the rotational mechanical energy from engine  20  to first electromagnetic device  40  through the shaft of first electromagnetic device  40  and neutral clutch  22  such that first electromagnetic device  40  generates electrical power. In some embodiments, a brake is applied to front axle  60  and/or rear axle  70  to prevent movement of the vehicle  10  in the power generation mode. 
     According to an alternative embodiment, engine  20  does not provide a rotational mechanical energy input to drive a vehicle. By way of example, first electromagnetic device  40 , second electromagnetic device  50 , and/or another device may store energy during the above mentioned modes of operation. When sufficient energy is stored (e.g., above a threshold level, etc.), at least one of first electromagnetic device  40  and second electromagnetic device  50  may provide a rotational mechanical energy output such that the vehicle is driven without an input from engine  20  (e.g., an electric mode, etc.). 
     As shown in  FIG. 13 , transmission  30  is selectively reconfigured into an electric PTO mode of operation such that first electromagnetic device  40  allows for operation of the PTO output  80  coupled to the secondary output clutch  42  without operation of engine  20  or transmission  30 . The electric PTO mode may be more efficient than other modes of operation that drive the PTO outputs  80  through the jackshaft  34 , as no energy is expended moving components of engine  20  or transmission  30  in the electric PTO mode. Further, without engine  20  and transmission  30  operating, the vehicle may operate more quietly overall (e.g., without engine noise, without noises generated by movement of gears in transmission  30 , etc.). In one embodiment, first electromagnetic device uses electrical energy from an energy storage device (e.g., a battery, a capacitor, etc.) and provides a rotational mechanical energy input to drive PTO output  80 . In such embodiments, the electric PTO mode facilitates driving the PTO output  80  without consuming fuel (e.g., as operation of engine  20  is not required). 
     As shown in  FIG. 13  and Table 1, neutral clutch  22  is disengaged and secondary output clutch  42  is engaged when transmission  30  is configured in the electric PTO mode. As shown in  FIG. 13 , secondary output clutch  42  couples the shaft of first electromagnetic device  40  to PTO output  80  when engaged. With neutral clutch  22  disengaged, first electromagnetic device  40  and PTO output  80  are rotationally decoupled from transmission  30  and thereby may rotate independently of both engine  20  and transmission  30 . Accordingly, with only secondary output clutch  42  engaged, energy flows directly from first electromagnetic device  40  to PTO output  80 . 
     Although the figures may show a specific order of method steps, the order of the steps may differ from what is depicted. Also two or more steps may be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps. 
     As utilized herein, the terms “approximately,” “about,” “substantially,” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims. 
     It should be noted that the terms “exemplary” and “example” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). 
     The terms “coupled,” “connected,” and the like, as used herein, mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent, etc.) or moveable (e.g., removable, releasable, etc.). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” “between,” etc.) are merely used to describe the orientation of various elements in the figures. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
     Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, Z, X and Y, X and Z, Y and Z, or X, Y, and Z (i.e., any combination of X, Y, and Z). Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present, unless otherwise indicated. 
     It is important to note that the construction and arrangement of the systems as shown in the exemplary embodiments is illustrative only. Although only a few embodiments of the present disclosure have been described in detail, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements. It should be noted that the elements and/or assemblies of the components described herein may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present inventions. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the preferred and other exemplary embodiments without departing from scope of the present disclosure or from the spirit of the appended claims.