Patent Publication Number: US-7715958-B2

Title: Hybrid energy power management system and method

Description:
FIELD OF THE INVENTION 
   The invention relates generally to locomotives, marine vehicles, and off-highway vehicles, and more particularly, to an energy management system for use with one of a plurality of hybrid energy diesel electric locomotives, marine vehicles and off-highway vehicles. 
   BACKGROUND OF THE INVENTION 
   Prior art diesel-electric locomotives typically include energy management systems to maximize the operating efficiency of the locomotive as it travels along its scheduled route. Currently, these energy management systems include an energy storage system for selectively storing and transferring secondary electrical energy while the locomotive propels along a track route. Such secondary electrical energy augments a source of primary electrical energy, particularly at track locations of high energy demand on the locomotive, thereby ensuring that the locomotive meets such demands and completes its route around the track. 
   Current energy management systems calculate the necessary storage and transfer energy amounts of the energy storage system at spaced time intervals around the track route, based upon track topographic information at each time interval, locomotive weight, and efficiency ratings, among other factors. These energy management systems further assesses upcoming energy demands and uses such assessments to ascertain the appropriate time to store and transfer secondary electrical energy to meet such demands. Thus, current energy management system engage in complex computation involving track topographic information and locomotive characteristics at each spaced time interval as the locomotive progresses around the track, in order to compute the necessary storage and transfer energy amounts for the energy storage system, for maximum operating efficiency. 
   Accordingly, there is a need for an automated energy management system to provide the necessary storage and transfer energy of the energy storage system, without the need to engage in complex computation involving track topographic information, or to reduce the complexity of such computations involving track topographic information. 
   SUMMARY OF THE INVENTION 
   In one aspect, the invention relates to an energy management system for use with one of a plurality of hybrid energy diesel electric locomotives. Each locomotive includes an engine and power converter which provide primary electric power, and a traction bus coupled to the power converter to carry the primary electric power. A traction motor is connected to the traction bus, and has a motoring mode responsive to the primary electric power to propel the one of a plurality of locomotives on the one of a plurality of routes. Additionally, the traction motor has a dynamic braking mode to generate dynamic braking electrical energy on the traction bus. The energy management system includes a position identification device to provide position information of the one of a plurality of locomotives at incremental positions along the one of a plurality of routes. In addition, the energy management system includes a database to store historical data of a traction and/or auxiliary energy demand for each of the plurality of locomotives at each of the incremental positions along each of the plurality of routes. More particularly, the energy management system includes an energy management processor coupled to the position identification device and the database to retrieve the historical data of each of the plurality of locomotives for each of the incremental positions along the one of a plurality of routes to estimate an anticipated traction and/or auxiliary energy demand of the one of a plurality of locomotives at each of the incremental positions along the one of a plurality of routes. 
   In another aspect, the invention relates to an energy management method for use with one of a plurality of hybrid energy diesel electric locomotives. Each locomotive includes an engine and power converter to provide primary electric power, a traction bus coupled to the power converter to carry the primary electric power, and a traction motor connected to the traction bus. The traction motor has a motoring mode responsive to the primary electric power to propel the one of a plurality of locomotives on the one of a plurality of routes. Additionally, the traction motor has a dynamic braking mode to generate dynamic braking electrical energy on the traction bus. The energy management method includes storing historical data of a traction and/or auxiliary energy demand for each of the plurality of locomotives at each of the incremental positions along each of the plurality of routes in a database. Additionally, the method includes retrieving the historical data of each of the plurality of locomotives for each of the incremental positions along the one of a plurality of routes. Upon retrieving the historical data, the method includes providing position information of the one of a plurality of locomotives at incremental positions along the one of a plurality of routes. The method further includes estimating an anticipated traction and/or auxiliary energy demand of the one of a plurality of locomotives at each of the incremental positions along the one of a plurality of routes. 
   In another aspect, the invention relates to computer readable media containing program instructions for use with one of a plurality of hybrid energy diesel electric locomotives. Each locomotive has an engine and power converter to provide primary electric power, a traction bus coupled to the power converter to carry the primary electric power, and a traction motor connected to the traction bus. The traction motor has a motoring mode responsive to the primary electric power to propel the one of a plurality of locomotives on the one of a plurality of routes. Additionally, the traction motor has a dynamic braking mode generating dynamic braking electrical energy on the traction bus. The computer readable media includes a computer program code to retrieve the historical data of each of the plurality of locomotives for each of the incremental positions along the one of a plurality of routes. Additionally, the computer readable media includes a computer program code to estimate an anticipated traction and/or auxiliary energy demand of the one of a plurality of locomotives at each of the incremental positions along the one of a plurality of routes. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a block diagram of a prior art diesel-electric locomotive. 
       FIG. 1B  is an electrical schematic of a prior art AC diesel-electric locomotive. 
       FIG. 2  is a block diagram of one embodiment of a hybrid energy locomotive system having a separate energy tender vehicle. 
       FIG. 3  is a block diagram of one embodiment of a hybrid energy locomotive system having a second engine for charging an energy storage system, including an energy storage system associated with an energy tender vehicle. 
       FIG. 4  is a block diagram illustrating one preferred embodiment of an energy storage and generation system suitable for use in connection with a hybrid energy locomotive system. 
       FIG. 5  is a block diagram illustrating an energy storage and generation system suitable for use in a hybrid energy locomotive system, including an energy management system for controlling the storage and regeneration of energy. 
       FIGS. 6A-6D  are timing diagrams that illustrate one embodiment of an energy management system for controlling the storage and regeneration of energy, including dynamic braking energy. 
       FIGS. 7A-7D  are timing diagrams that illustrate another embodiment energy management system for controlling the storage and regeneration of energy, including dynamic braking energy. 
       FIGS. 8A-8E  are timing diagrams that illustrate another embodiment energy management system for controlling the storage and regeneration of energy, including dynamic braking energy. 
       FIGS. 9A-9G  are electrical schematics illustrating several embodiments of an electrical system suitable for use in connection with a hybrid energy off-highway vehicle, such as a diesel-electric locomotive. 
       FIGS. 10A-10C  are electrical schematics illustrating additional embodiments of an electrical system suitable for use in connection with a hybrid energy off-highway vehicle, such as a diesel-electric locomotive. 
       FIG. 11  is an electrical schematic that illustrates one preferred way of connecting electrical storage elements. 
       FIG. 12  is a flow chart that illustrates one method of operating a hybrid energy locomotive system. 
       FIG. 13  is a block diagram illustrating an exemplary embodiment of an energy storage and generation system suitable for use in a hybrid energy locomotive system, including an energy management system for controlling the storage and regeneration of energy. 
       FIG. 14  is an exemplary embodiment of a spatial diagram illustrating a plurality of historical traction and/or auxiliary energy demand versus incremental position along one of a plurality of routes. 
       FIG. 15  is an exemplary embodiment of a spatial diagram illustrating a plurality of historical traction and/or auxiliary energy demand values at a fixed location along one of a plurality of routes versus each trial along the one of a plurality of routes. 
       FIG. 16  is an exemplary embodiment of a spatial diagram of a currently anticipated traction energy, energy storage device energy and energy storage device power versus incremental position along one of a plurality of routes. 
       FIG. 17  is a spatial diagram of an anticipated traction energy, energy storage device energy and energy storage device power utilizing an exemplary embodiment of an energy management system versus incremental position along one of a plurality of routes. 
       FIG. 18  is a flow chart illustrating an exemplary method embodiment of the system illustrated in  FIG. 13 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Though exemplary embodiments of the present invention are described with respect to rail vehicles, specifically trains and locomotives having diesel engines, exemplary embodiments of the invention are also applicable for other uses, such as but not limited to off-highway vehicles, marine vessels, and stationary units, each which may use a diesel engine. Towards this end, when discussing a specified mission, this includes a task or requirement to be performed by the diesel powered system. Therefore, with respect to railway, marine or off-highway vehicle applications this may refer to the movement of the system from a present location to a destination. In the case of stationary applications, such as but not limited to a stationary power generating station or network of power generating stations, a specified mission may refer to an amount of wattage (e.g., MW/hr) or other parameter or requirement to be satisfied by the diesel powered system. Likewise, operating condition of the diesel-fueled power generating unit may include one or more of speed, load, fueling value, timing, etc. Stationary applications are applicable to those embodiments of the present invention in which anticipated traction and/or auxiliary energy demand for rail vehicles is determined for fixed time increments based upon historical data of traction and/or auxiliary energy demand at those same fixed time increments, as discussed below. 
   In one exemplary example involving marine vessels, a plurality of tugs may be operating together where all are moving the same larger vessel, where each tug is linked in time to accomplish the mission of moving the larger vessel. In another exemplary example a single marine vessel may have a plurality of engines. Off Highway Vehicle (OHV) may involve a fleet of vehicles that have a same mission to move along earth, from location A to location B, where each ORV is linked in time to accomplish the mission. With respect to a stationary power generating station, a plurality of stations may be grouped together collectively generating power for a specific location and/or purpose. In another exemplary embodiment, a single station is provided, but with a plurality of generators making up the single station. 
     FIG. 2  is a block diagram of one embodiment of a hybrid energy locomotive system  200 . In this embodiment, the hybrid energy locomotive system preferably includes an energy tender vehicle  202  for capturing and regenerating at least a portion of the dynamic braking electric energy generated when the locomotive traction motors operate in a dynamic braking mode. The energy tender vehicle  202  is constructed and arranged to be coupled to the locomotive in a consist configuration, and includes an energy capture and storage system  204  (sometimes referred to as an energy storage medium or an energy storage). It should be understood that it is common to use two or more locomotives in a consist configuration and that  FIG. 2  illustrates a single locomotive for convenience. 
   In one embodiment, the energy capture and storage system  204  selectively receives electrical power generated during the dynamic braking mode of operation and stores it for later regeneration and use. In the alternative or in addition to receiving and storing dynamic braking power, energy capture and storage system  204  can also be constructed and arranged to receive and store power from other sources. For example, excess prime mover power from engine  102  can be transferred and stored. Similarly, when two or more locomotives are operating in a consist, excess power from one of the locomotives can be transferred and stored in energy capture and storage system  204 . Also, a separate power generator (e.g., diesel generator) can be used to supply a charging voltage (e.g., a constant charging voltage) to energy capture and storage system. Still another source of charging is an optional off-train charging source  220 . For example, energy capture and storage system  204  can be charged by external sources such as a battery charger in a train yard or at a wayside station. 
   The energy capture and storage system  204  preferably includes at least one of the following storage subsystems for storing the electrical energy generated during the dynamic braking mode: a battery subsystem, a flywheel subsystem, or an ultra-capacitor subsystem. Other storage subsystems are possible. Ultra-capacitors are available from Maxwell Technologies. These storage subsystems may be used separately or in combination. When used in combination, these storage subsystems can provide synergistic benefits not realized with the use of a single energy storage subsystem. A flywheel subsystem, for example, typically stores energy relatively fast but may be relatively limited in its total energy storage capacity. A battery subsystem, on the other hand, often stores energy relatively slowly but can be constructed to provide a relatively large total storage capacity. Hence, a flywheel subsystem may be combined with a battery subsystem wherein the flywheel subsystem captures the dynamic braking energy that cannot be timely captured by the battery subsystem. The energy thus stored in the flywheel subsystem may be thereafter used to charge the battery. Accordingly, the overall capture and storage capabilities are preferably extended beyond the limits of either a flywheel subsystem or a battery subsystem operating alone. Such synergies can be extended to combinations of other storage subsystems, such as a battery and ultra-capacitor in combination where the ultra-capacitor supplies the peak demand needs. 
   It should be noted at this point that, when a flywheel subsystem is used, a plurality of flywheels is preferably arranged to limit or eliminate the gyroscopic effect each flywheel might otherwise have on the locomotive and load vehicles. For example, the plurality of flywheels may be arranged on a six-axis basis to greatly reduce or eliminate gyroscopic effects. It should be understood, however, that reference herein to a flywheel embraces a single flywheel or a plurality of flywheels. 
   Referring still to  FIG. 2 , energy capture and storage system  204  not only captures and stores electric energy generated in the dynamic braking mode of the locomotive, it also supplies the stored energy to assist the locomotive effort (i.e., to supplement and/or replace prime mover power). For example, energy tender vehicle  202  optionally includes a plurality of energy tender traction motors  208  mounted on the trucks supporting energy tender vehicle  202 . The electrical power stored in energy capture and storage  204  may be selectively supplied (e.g., via lines  210 ) to the energy tender traction motors  208 . Thus, during times of increased demand, energy tender traction motors  208  augment the tractive power provided by locomotive traction motors  108 . As another example, during times when it is not possible to store more energy from dynamic braking (e.g., energy storage system  204  is charged to capacity), efficiency considerations may suggest that energy tender traction motors  208  also augment locomotive traction motors  108 . 
   It should be appreciated that when energy capture and storage system  204  drives energy tender traction motors  208 , additional circuitry will likely be required. For example, if energy capture and storage system  204  comprises a battery storing and providing a DC voltage, one or more inverter drives may be used to convert the DC voltage to a form suitable for use by the energy tender traction motors  208 . Such drives are preferably operationally similar to those associated with the main locomotive. 
   Rather than (or in addition to) using the electrical power stored in energy capture and storage  204  for powering separate energy tender traction motors  208 , such stored energy may also be used to augment the electrical power supplied to locomotive traction motors  108  (e.g., via line  212 ). 
   Other configurations are also possible. For example, the locomotive itself may be constructed and arranged (e.g., either during manufacturing or as part of a retrofit program) to capture, store, and regenerate excess electrical energy, such as dynamic braking energy or excess motor power. In another embodiment, a locomotive may be replaced with an autonomous tender vehicle. In still another embodiment, similar to the embodiment illustrated in  FIG. 2 , the separate energy tender vehicle is used solely for energy capture, storage, and regeneration—the tender does not include the optional traction motors  208 . In yet another embodiment, a separate tender vehicle is replaced with energy capture and storage subsystems located on some or all of the load units attached to the locomotive. Such load units may optionally include separate traction motors. In each of the foregoing embodiments, the energy capture and storage subsystem can include one or more of the subsystems previously described. 
   When a separate energy tender vehicle (e.g., energy tender vehicle  202 ) is used, the tender vehicle  202  and the locomotive are preferably coupled electrically (e.g., via line  212 ) such that dynamic braking energy from the locomotive traction motors and/or from optional energy tender traction motors  208  is stored in energy storage means on board the tender. During motoring operations, the stored energy is selectively used to propel locomotive traction motors  108  and/or optional traction motors  208  of tender vehicle  202 . Similarly, when the locomotive engine produces more power than required for motoring, the excess prime mover power can be stored in energy capture and storage  202  for later use. 
   If energy tender vehicle  202  is not electrically coupled to the locomotive (other than for standard control signals), traction motors  208  on the tender vehicle can also be used in an autonomous fashion to provide dynamic braking energy to be stored in energy capture and storage  204  for later use. One advantage of such a configuration is that tender vehicle  202  can be coupled to a wide variety of locomotives, in almost any consist. 
   It should be appreciated that when energy tender traction motors  208  operate in a dynamic braking mode, various reasons may counsel against storing the dynamic braking energy in energy capture and storage  204  (e.g., the storage may be full). Thus, it is preferable that some or all of such dynamic braking energy be dissipated by grids associated with energy tender vehicle  202  (not shown), or transferred to locomotive grids  110  (e.g., via line  212 ). 
   The embodiment of  FIG. 2  will be further described in terms of one possible operational example. It is to be understood that this operational example does not limit the invention. The locomotive system  200  is configured in a consist including a locomotive (e.g., locomotive  100  of  FIG. 1 ), an energy tender vehicle  202 , and at least one load vehicle. The locomotive may be, for example, an AC diesel-electric locomotive. Tractive power for the locomotive is supplied by a plurality of locomotive traction motors  108 . In one preferred embodiment, the locomotive has six axles, each axle includes a separate locomotive traction motor, and each traction motor is an AC traction motor. The locomotive includes a diesel engine  102  that drives an electrical power system. More particularly, the diesel engine drives an alternator/rectifier that comprises a source of prime mover electrical power (sometimes referred to as traction power or primary power). In this particular embodiment, the prime mover electrical power is DC power that is converted to AC power for use by the traction motors. More specifically, one or more inverters (e.g., inverter  106 ) receive the prime mover electrical power and selectively supply AC power to the plurality of locomotive traction motors  108  to propel the locomotive. Thus, locomotive traction motors  108  propel the locomotive in response to the prime mover electrical power. 
   Each of the plurality of locomotive traction motors  108  is preferably operable in at least two operating modes, a motoring mode and a dynamic braking mode. In the motoring mode, the locomotive traction motors  108  receive electrical power (e.g., prime mover electrical power via inverters) to propel the locomotive. As described elsewhere herein, when operating in the dynamic braking mode, the traction motors generate electricity. In the embodiment of  FIG. 2 , energy tender vehicle  202  is constructed and arranged to selectively capture and store a portion of the electricity generated by the traction motors during dynamic braking operations. This is accomplished by energy capture and storage system  204 . The captured and stored electricity is selectively used to provide a secondary source of electric power. This secondary source of electric power may be used to selectively supplement or replace the prime mover electrical power (e.g., to help drive one or more locomotive traction motors  108 ) and/or to drive one or more energy tender traction motors  208 . In the latter case, energy tender traction motors  208  and locomotive traction motors  108  cooperate to propel the consist. 
   Advantageously, tender capture and storage  204  can store dynamic braking energy without any electrical power transfer connection with the primary locomotive. In other words, energy capture and storage  204  can be charged without a connection such as line  212 . This is accomplished by operating the locomotive engine  102  to provide motoring power to locomotive traction motors  108  while operating tender vehicle  202  in a dynamic braking mode. For example, the locomotive engine  102  may be operated at a relatively high notch setting while tender vehicle traction motors  208  are configured for dynamic braking. Energy from the dynamic braking process can be used to charge energy capture and storage  204 . Thereafter, the stored energy can be used to power energy tender traction motors  208  to provide additional motoring power to the train. One of the advantages of such a configuration is that tender vehicle  202  can be placed anyway in the train. For example, in one wireless embodiment, tender vehicle  202  provides its own local power (e.g., for controls or lighting) and communicates via a radio link with other vehicles in the train, as necessary. An air brake connection would likely also be connected to tender vehicle  202 . Of course, minimal wiring such as standard lighting wiring and control wiring could be optionally routed to tender vehicle  202 , if so desired. 
   It is known in the art that diesel-electric locomotives are often loud and the vibrations associated with the engine make the environment uncomfortable for train operators. Accordingly, in one embodiment, tender vehicle  202  is modified to include an operator compartment such that the train engineer can operate the train from the relative comfort of the tender, rather than from the locomotive.  FIG. 2  reflects this schematically at the aft end of tender  202  with reference character  230 . 
     FIG. 3  is a block diagram of another embodiment of a hybrid energy locomotive system  300 . This embodiment includes a second engine vehicle  301  for charging the energy tender vehicle  202 . The second engine vehicle  301  comprises a diesel engine  302  that is preferably smaller than the main locomotive engine  102 , but which otherwise operates according similar principles. For example, second engine vehicle  301  comprises an alternator/rectifier  304  (driven by the second engine  302 ), one or more inverters  306 , and a plurality of braking grids  310 . In one embodiment, second engine  302  runs at a constant speed to provide a constant charging source (e.g., 200-400 hp) for energy tender vehicle  202 . Thus, when a hybrid energy locomotive system is configured as shown in  FIG. 3 , energy capture and storage  204  preferably receives charging energy from one or both of the primary locomotive (e.g., dynamic braking energy), and second engine vehicle  301  (e.g., direct charging) via line  312 . It should be understood that, although second engine vehicle  301  is shown as a separate vehicle, it could also be included, for example, as an integral part of energy tender vehicle  202  or a load vehicle. Also, dynamic braking generators (e.g., via traction motors  308 ) could be optionally included with second engine  301  thereby providing an additional source of power for storage in energy capture and storage  204 . 
     FIG. 4  is a system-level block diagram that illustrates aspects of one preferred energy storage and generation system. In particular,  FIG. 4  illustrates an energy storage and generation system  400  suitable for use with a hybrid energy locomotive system, such as hybrid energy locomotive system  200  or system  300  ( FIGS. 2 and 3 ). Such an energy storage and generation system  400  could be implemented, for example, as part of a separate energy tender vehicle (e.g.,  FIGS. 2 and 3 ) and/or incorporated into a locomotive. 
   As illustrated in  FIG. 4 , a diesel engine  102  drives a prime mover power source  104  (e.g., an alternator/rectifier converter). The prime mover power source  104  preferably supplies DC power to an inverter  106  that provides three-phase AC power to a locomotive traction motor  108 . It should be understood, however, that the system  400  illustrated in  FIG. 4  can be modified to operate with DC traction motors as well. Preferably, there is a plurality of traction motors (e.g., one per axle), and each axle is coupled to a plurality of locomotive wheels. In other words, each locomotive traction motor preferably includes a rotatable shaft coupled to the associated axle for providing tractive power to the wheels. Thus, each locomotive traction motor  108  provides the necessary motoring force to an associated plurality of locomotive wheels  109  to cause the locomotive to move. 
   When traction motors  108  are operated in a dynamic braking mode, at least a portion of the generated electrical power is routed to an energy storage medium such as energy storage  204 . To the extent that energy storage  204  is unable to receive and/or store all of the dynamic braking energy, the excess energy is preferably routed to braking grids  110  for dissipation as heat energy. Also, during periods when engine  102  is being operated such that it provides more energy than needed to drive traction motors  108 , the excess capacity (also referred to as excess prime mover electric power) may be optionally stored in energy storage  204 . Accordingly, energy storage  204  can be charged at times other than when traction motors  108  are operating in the dynamic braking mode. This aspect of the system is illustrated in  FIG. 4  by a dashed line  402 . 
   The energy storage  204  of  FIG. 4  is preferably constructed and arranged to selectively augment the power provided to traction motors  108  or, optionally, to power separate traction motors associated with a separate energy tender vehicle (see  FIG. 2  above) or a load vehicle. Such power may be referred to as secondary electric power and is derived from the electrical energy stored in energy storage  204 . Thus, the system  400  illustrated in  FIG. 4  is suitable for use in connection with a locomotive having an on-board energy storage medium and/or with a separate energy tender vehicle. 
     FIG. 5  is a block diagram that illustrates aspects of one preferred embodiment of an energy storage and generation system  500  suitable for use with a hybrid energy locomotive system. The system  500  includes an energy management system  502  for controlling the storage and regeneration of energy. It should be understood, however, that the energy management system  502  illustrated in  FIG. 5  is also suitable for use with other large, off-highway vehicles that travel along a relatively well-defined course. Such vehicles include, for example, large excavators, excavation dump trucks, and the like. By way of further example, such large excavation dump trucks may employ motorized wheels such as the GEB23.™. AC motorized wheel employing the GE150AC.™. drive system (both of which are available from the assignee of the present invention). Therefore, although  FIG. 5  is generally described with respect to a locomotive system, the energy management system  500  illustrated therein is not to be considered as limited to locomotive applications. 
   Referring still to the exemplary embodiment illustrated in  FIG. 5 , system  500  preferably operates in the same general manner as system  400  of  FIG. 4 ; the energy management system  502  provides additional intelligent control functions.  FIG. 5  also illustrates an optional energy source  504  that is preferably controlled by the energy management system  502 . The optional energy source  504  may be a second engine (e.g., the charging engine illustrated in  FIG. 3  or another locomotive in the consist) or a completely separate power source (e.g., a wayside power source such as a battery charger) for charging energy storage  204 . In one embodiment, such a separate charger includes an electrical power station for charging an energy storage medium associated with a separate energy tender vehicle (e.g., vehicle  202  of  FIG. 2 ) while stationary, or a system for charging the energy storage medium while the tender vehicle is in motion. In one preferred embodiment, optional energy source  504  is connected to a traction bus (not illustrated in  FIG. 5 ) that also carries primary electric power from prime mover power source  104 . 
   As illustrated, the energy management system  502  preferably includes an energy management processor  506 , a database  508 , and a position identification system  510 , such as, for example, a global positioning satellite system receiver (GPS)  510 . The energy management processor  506  determines present and anticipated train position information via the position identification system  510 . In one embodiment, energy management processor  506  uses this position information to locate data in the database  508  regarding present and/or anticipated track topographic and profile conditions, sometimes referred to as track situation information. Such track situation information may include, for example, track grade, track elevation (e.g., height above mean sea level), track curve data, tunnel information, speed limit information, and the like. It is to be understood that such database information could be provided by a variety of sources including: an onboard database associated with processor  510 , a communication system (e.g., a wireless communication system) providing the information from a central source, manual operator input(s), via one or more wayside signaling devices, a combination of such sources, and the like. Finally, other vehicle information such as, the size and weight of the vehicle, a power capacity associated with the prime mover, efficiency ratings, present and anticipated speed, present and anticipated electrical load, and so on may also be included in a database (or supplied in real or near real time) and used by energy management processor  506 . It should be appreciated that, in an alternative embodiment, energy management system  502  could be configured to determine power storage and transfer requirements associated with energy storage  204  in a static fashion. For example, energy management processor  506  could be preprogrammed with any of the above information, or could use look-up tables based on past operating experience (e.g., when the vehicle reaches a certain point, it is nearly always necessary to store additional energy to meet an upcoming demand). 
   The energy management processor  506  preferably uses the present and/or upcoming track situation information, along with vehicle status information, to determine power storage and power transfer requirements. Energy management processor  506  also determines possible energy storage opportunities based on the present and future track situation information. For example, based on the track profile information, energy management processor  506  may determine that it is more efficient to completely use all of the stored energy, even though present demand is low, because a dynamic braking region is coming up (or because the train is behind schedule and is attempting to make up time). In this way, the energy management system  502  improves efficiency by accounting for the stored energy before the next charging region is encountered. As another example, energy management processor  506  may determine not to use stored energy, despite present demand, if a heavier demand is upcoming. Advantageously, energy management system  502  may also be configured to interface with engine controls. Also, as illustrated in  FIG. 5 , energy storage  204  may be configured to provide an intelligent control interface with energy management system  502 . 
   In operation, energy management processor  506  determines a power storage requirement and a power transfer requirement. Energy storage  204  stores electrical energy in response to the power storage requirement. Energy storage  204  provides secondary electric power (e.g. to a traction bus connected to inverters  106  to assist in motoring) in response to the power transfer requirement. The secondary electric power is derived from the electrical energy stored in energy storage  204 . 
   As explained above, energy management processor  506  preferably determines the power storage requirement based, in part, on a situation parameter indicative of a present and/or anticipated track topographic characteristic. Energy management processor  506  may also determine the power storage requirement as a function of an amount of primary electric power available from the prime mover power source  104 . Similarly, energy management processor  506  may determine the power storage requirement as function of a present or anticipated amount of primary electric power required to propel the locomotive system. 
   Also, in determining the energy storage requirement, energy management processor  506  preferably considers various parameters related to energy storage  204 . For example, energy storage  204  will have a storage capacity that is indicative of the amount of power that can be stored therein and/or the amount of power that can be transferred to energy storage  204  at any given time. Another similar parameter relates to the amount of secondary electric power that energy storage  204  has available for transfer at a particular time. 
   As explained above, system  500  preferably includes a plurality of sources for charging energy storage  204 . These sources include dynamic braking power, excess prime mover electric power, and external charging electric power. Preferably, energy management processor  506  determines which of these sources should charge energy storage  204 . In one embodiment, present or anticipated dynamic braking energy is used to charge energy storage  204 , if such dynamic braking energy is available. If dynamic braking energy is not available, either excess prime mover electric power or external charging electric power is used to charge energy storage  204 . 
   In the embodiment of  FIG. 5 , energy management processor  506  preferably determines the power transfer requirement as a function of a demand for power. In other words, energy storage  204  preferably does not supply secondary electric power unless traction motors  108  are operating in a power consumption mode (i.e., a motoring mode, as opposed to a dynamic braking mode). In one form, energy management processor  506  permits energy storage  204  to supply secondary electric power to inverters  106  until either (a) the demand for power terminates or (b) energy storage  204  is completely depleted. In another form, however, energy management processor  506  considers anticipated power demands and controls the supply of secondary electric power from energy storage  204  such that sufficient reserve power remains in energy storage  204  to augment prime mover power source during peak demand periods. This may be referred to as a “look ahead” energy management scheme. 
   In the look ahead energy management scheme, energy management processor  506  preferably considers various present and/or anticipated track situation parameters, such as those discussed above. In addition, energy management processor may also consider the amount of power stored in energy storage  204 , anticipated charging opportunities, and any limitations on the ability to transfer secondary electric power from energy storage  204  to inverters  106 . 
     FIGS. 6A-D ,  7 A-D, and  8 A-E illustrate, in graphic form, aspects of three different embodiments of energy management systems, suitable for use with a hybrid energy vehicle, that could be implemented in a system such as system  500  of  FIG. 5 . It should be appreciated that these figures are provided for exemplary purposes and that, with the benefit of the present disclosure, other variations are possible. It should also be appreciated that the values illustrated in these figures are included to facilitate a detailed description and should not be considered in a limiting sense. It should be further understood that, although the examples illustrated in these figures relate to locomotives and trains, the energy management system and methods identified herein may be practiced with a variety of large, off-highway vehicles that traverse a known course and which are generally capable of storing the electric energy generated during the operation of such vehicles. Such off-highway vehicles include vehicles using DC and AC traction motor drives and having dynamic braking/retarding capabilities. 
   There are four similar charts in each group of figures ( FIGS. 6A-D ,  FIGS. 7A-D , and  FIGS. 8A-D ). The first chart in each group (i.e.,  FIGS. 6A ,  7 A, and  8 A) illustrates the required power for both motoring and braking. Thus, the first chart graphically depicts the amount of power required by the vehicle. Positive values on the vertical axis represent motoring power (horsepower); negative values represent dynamic braking power. It should be understood that motoring power could originate with the prime mover (e.g., diesel engine in a locomotive), or from stored energy (e.g., in an energy storage medium in a separate energy tender vehicle or in a locomotive), or from a combination of the prime mover and stored energy. Dynamic braking power could be dissipated or stored in the energy storage medium. 
   The horizontal axis in all charts reflects time in minutes. The time basis for each chart in a given figure group are intended to be the same. It should be understood, however, that other reference bases are possible. 
   The second chart in each group of figures (i.e.,  FIGS. 6B ,  7 B, and  8 B) reflects theoretical power storage and consumption. Positive values reflect the amount of power that, if power were available in the energy storage medium, could be drawn to assist in motoring. Negative values reflect the amount of power that, if storage space remains in the energy storage medium, could be stored in the medium. The amount of power that could be stored or drawn is partially a function of the converter and storage capabilities of a given vehicle configuration. For example, the energy storage medium will have some maximum/finite capacity. Further, the speed at which the storage medium is able to accept or supply energy is also limited (e.g., batteries typically charge slower than flywheel devices). Other variables also affect energy storage. These variables include, for example, ambient temperature, the size and length of any interconnect cabling, current and voltage limits on dc-to-dc converters used for battery charging, power ratings for an inverter for a flywheel drive, the charging and discharging rates of a battery, or a motor/shaft limit for a flywheel drive. The second chart assumes that the maximum amount of power that could be transferred to or from the energy storage medium at a given time is 500 h.p. Again, it should be understood that this 500 h.p. limit is included for exemplary purposes. Hence, the positive and negative limits in any given system could vary as a function of ambient conditions, the state and type of the energy storage medium, the type and limits of energy conversion equipment used, and the like. 
   The third chart in each figure group (i.e.,  FIGS. 6C ,  7 C, and  8 C) depicts a power transfer associated with the energy storage medium. In particular, the third chart illustrates the actual power being transferred to and from the energy storage medium versus time. The third chart reflects limitations due to the power available for storage, and limitations due to the present state of charge/storage of the energy storage medium (e.g., the speed of the flywheel, the voltage in an ultra-capacitor, the charge in the battery, and the like). 
   The fourth chart in each figure group (i.e.,  FIGS. 6D ,  7 D, and  8 D) depicts actual energy stored. In particular, the fourth chart illustrates the energy stored in the energy storage medium at any particular instant in time. 
   Referring first to  FIGS. 6A-D , these figures reflect an energy management system that stores energy at the maximum rate possible during dynamic braking until the energy storage medium is completely full. In this embodiment, all energy transfers to the storage medium occur during dynamic braking. In other words, in the embodiment reflected in  FIGS. 6A-D , no energy is transferred to the energy storage medium from excess prime mover power available during motoring, or from other energy sources. Similarly, energy is discharged, up to the maximum rate, whenever there is a motor demand (limited to and not exceeding the actual demand) until the energy storage medium is completely discharged/empty.  FIGS. 6A-D  assume that the energy storage medium is completely discharged/empty at time 0. 
   Referring now specifically to  FIG. 6A , as mentioned above, the exemplary curve identified therein illustrates the power required (utilized) for motoring and dynamic braking. Positive units of power reflect when motoring power is being applied to the wheels of the vehicle (e.g., one or more traction motors are driving locomotive wheels). Negative units of power reflect power generated by dynamic braking. 
     FIG. 6B  is an exemplary curve that reflects power transfer limits. Positive values reflect the amount of stored energy that would be used to assist in the motoring effort, if such energy were available. Negative units reflect the amount of dynamic braking energy that could be stored in the energy storage medium if the medium were able to accept the full charge available. In the example of  FIG. 6B , the energy available for storage at any given time is illustrated as being limited to 500 units (e.g., horsepower). As explained above, a variety of factors limit the amount of power that can be captured and transferred. Thus, from about 0 to 30 minutes, the locomotive requires less than 500 h.p. If stored energy were available, it could be used to provide all of the motoring power. From about 30 minutes to about 65 or 70 minutes, the locomotive requires more than 500 h.p. Thus, if stored energy were available, it could supply some (e.g., 500 h.p.) but not all of the motoring power. From about 70 minutes to about 75 minutes or so, the locomotive is in a dynamic braking mode and generates less than 500 h.p. of dynamic braking energy. Thus, up to 500 h.p. of energy could be transferred to the energy storage medium, if the medium retained sufficient capacity to store the energy. At about 75 minutes, the dynamic braking process generates in excess of 500 h.p. Because of power transfer limits, only up to 500 h.p. could be transferred to the energy storage medium (again, assuming that storage capacity remains); the excess power would be dissipated in the braking grids. It should be understood that  FIG. 6B  does not reflect the actual amount of energy transferred to or from the energy storage medium. That information is depicted in  FIG. 6C . 
     FIG. 6C  is reflects the power transfer to/from the energy storage medium at any given instant of time. The example shown therein assumes that the energy storage medium is completely empty at time 0. Therefore, the system cannot transfer any power from the storage at this time. During a first time period A (from approximately 0-70 minutes), the vehicle is motoring (see  FIG. 6A ) and no power is transferred to or from the energy storage. At the end of the first time period A, and for almost 30 minutes thereafter, the vehicle enters a dynamic braking phase (see  FIG. 6A ). During this time, power from the dynamic braking process is available for storage (see  FIG. 6B ). 
   During a second time period B (from approximately 70-80 minutes), dynamic braking energy is transferred to the energy storage medium at the maximum rate (e.g., 500 units) until the storage is full. During this time there is no motoring demand to deplete the stored energy. Thereafter, during a third time period C (from approximately 80-105 minutes), the storage is full. Consequently, even though the vehicle remains in the dynamic braking mode or is coasting (see  FIG. 6A ), no energy is transferred to or from the energy storage medium during time period C. 
   During a fourth time period D (from approximately 105-120 minutes), the vehicle resumes motoring. Because energy is available in the energy storage medium, energy is drawn from the storage and used to assist the motoring process. Hence, the curve illustrates that energy is being drawn from the energy storage medium during the fourth time period D. 
   At approximately 120 minutes, the motoring phase ceases and, shortly thereafter, another dynamic braking phase begins. This dynamic braking phase reflects the start of a fifth time period E which lasts from approximately 125-145 minutes. As can be appreciated by viewing the curve during the fifth time period E, when the dynamic braking phase ends, the energy storage medium is not completely charged. 
   Shortly before the 150-minute point, a sixth time period F begins which lasts from approximately 150-170 minutes. During this time period and thereafter (see  FIG. 6A ), the vehicle is motoring. From approximately 150-170 minutes, energy is transferred from the energy storage medium to assist in the motoring process. At approximately 170 minutes, however, the energy storage is completely depleted. Accordingly, from approximately 170-200 minutes (the end of the sample window), no energy is transferred to or from the energy storage medium. 
     FIG. 6D  illustrates the energy stored in the energy storage medium of the exemplary embodiment reflected in  FIGS. 6A-D . Recall that in the present example, the energy storage medium is assumed to be completely empty/discharged at time 0. Recall also that the present example assumes an energy management system that only stores energy from dynamic braking. From approximately 0-70 minutes, the vehicle is motoring and no energy is transferred to or from the energy storage medium. From approximately 70-80 minutes or so, energy from dynamic braking is transferred to the energy storage medium until it is completely full. At approximately 105 minutes, the vehicle begins another motoring phase and energy is drawn from the energy storage medium until about 120 minutes. At about 125 minutes, energy from dynamic braking is again transferred to the energy storage medium during another dynamic braking phase. At about 145 minutes or so, the dynamic braking phase ends and storage ceases. At about 150 minutes, energy is drawn from the energy storage medium to assist in motoring until all of the energy has been depleted at approximately 170 minutes. 
     FIGS. 7A-D  correspond to an energy management system that includes a “look ahead” or anticipated needs capability. Such a system is unlike the system reflected in  FIGS. 6A-D , which simply stores dynamic braking energy when it can, and uses stored energy to assist motoring whenever such stored energy is available. The energy management system reflected by the exemplary curves of  FIGS. 7A-D  anticipates when the prime mover cannot produce the full required demand, or when it may be less efficient for the prime mover to produce the full required demand. As discussed elsewhere herein, the energy management system can make such determinations based on, for example, known present position, present energy needs, anticipated future track topography, anticipated future energy needs, present energy storage capacity, anticipated energy storage opportunities, and like considerations. The energy management system depicted in  FIGS. 7A-D , therefore, preferably prevents the energy storage medium from becoming depleted below a determined minimum level required to meet future demands. 
   By way of further example, the system reflected in  FIGS. 7A-D  is premised on a locomotive having an engine that has a “prime mover limit” of 4000 h.p. Such a limit could exist for various factors. For example, the maximum rated output could be 4000 h.p., or operating efficiency considerations may counsel against operating the engine above 4000 h.p. It should be understood, however, that the system and figures are intended to reflect an exemplary embodiment only, and are presented herein to facilitate a detailed explanation of aspects of an energy management system suitable for use with off-highway hybrid energy vehicles such as, for example, the locomotive system illustrated in  FIG. 2 . 
   Referring now to  FIG. 7A , the exemplary curve illustrated therein depicts the power required for motoring (positive) and braking (negative). At approximately 180 minutes, the motoring demand exceeds 4000 h.p. Thus, the total demand at that time exceeds the 4000 h.p. operating constraint for the engine. The “look ahead” energy management system reflected in  FIGS. 7A-D , however, anticipates this upcoming need and ensures that sufficient secondary power is available from the energy storage medium to fulfill the energy needs. 
   One way for the energy management system to accomplish this is to look ahead (periodically or continuously) to the upcoming track/course profile (e.g., incline/decline, length of incline/decline, and the like) for a given time period (also referred to as a look ahead window). In the example illustrated in  FIGS. 7A-D , the energy management system looks ahead 200 minutes and then computes energy needs/requirements backwards. The system determines that, for a brief period beginning at 180 minutes, the engine would require more energy than the preferred limit. 
     FIG. 7B  is similar to  FIG. 6B .  FIG. 7B , however, also illustrates the fact that the energy storage medium is empty at time 0 and, therefore, there can be no power transfer from the energy storage medium unless and until it is charged.  FIG. 7B  also reflects a look ahead capability. 
   Comparing  FIGS. 6A-D  with  FIGS. 7A-D , it is apparent how the systems respectively depicted therein differ. Although the required power is the same in both examples (see  FIGS. 6A and 7A ), the system reflected in  FIGS. 7A-D  prevents complete discharge of the energy storage medium prior to the anticipated need at 180 minutes. Thus, as can be seen in  FIGS. 7C and 7D , prior to the 180 minute point, the system briefly stops transferring stored energy to assist in motoring, even though additional stored energy remains available. The additional energy is thereafter transferred, beginning at about 180 minutes, to assist the prime mover when the energy demand exceeds 4000 h.p. Hence, the system effectively reserves some of the stored energy to meet upcoming demands that exceed the desired limit of the prime mover. 
   It should be understood and appreciated that the energy available in the energy storage medium could be used to supplement driving traction motors associated with the prime mover, or could also be used to drive separate traction motors (e.g., on a tender or load vehicle). With the benefit of the present disclosure, an energy management system accommodating a variety of configurations is possible. 
     FIGS. 8A-E  reflect pertinent aspects of another embodiment of an energy management system suitable for use in connection with off-highway hybrid energy vehicles. The system reflected in  FIGS. 8A-E  includes a capability to store energy from both dynamic braking and from the prime mover (or another charging engine such as that illustrated in  FIG. 3 ). For example, a given engine may operate most efficiently at a given power setting (e.g., 4000 h.p.). Thus, it may be more efficient to operate the engine at 4000 h.p. at certain times, even when actual motoring demand falls below that level. In such cases, the excess energy can be transferred to an energy storage medium. 
   Thus, comparing  FIGS. 8A-D  with  FIGS. 6A-D  and  7 A-D, the differences between the systems respectively depicted therein become apparent. Referring specifically to  FIGS. 8A and 8D , from about 0-70 minutes, the motoring requirements ( FIG. 8A ) are less than the exemplary optimal 4000 h.p. setting. If desirable, the engine could be run at 4000 h.p. during this time and the energy storage medium could be charged. As illustrated, however, the energy management system determines that, based on the upcoming track profile and anticipated dynamic braking period(s), an upcoming dynamic braking process will be able to fully charge the energy storage medium. In other words, it is not necessary to operate the engine at 4000 h.p. and store the excess energy in the energy storage medium during this time because an upcoming dynamic braking phase will supply enough energy to fully charge the storage medium. It should be understood that the system could also be designed in other ways. For example, in another configuration the system always seeks to charge the storage medium whenever excess energy could be made available. 
   At approximately 180 minutes, power demands will exceed 4000 h.p. Thus, shortly before that time (while motoring demand is less than 4000 h.p.), the engine can be operated at 4000 h.p., with the excess energy used to charge the energy storage medium to ensure sufficient energy is available to meet the demand at 180 minutes. Thus, unlike the systems reflected in  FIGS. 6D and 7D , the system reflected in  FIG. 8D  provides that, for a brief period prior to 180 minutes, energy is transferred to the energy storage medium from the prime mover, even though the vehicle is motoring (not braking). 
     FIG. 8E  illustrates one way that the energy management system can implement the look ahead capability to control energy storage and transfer in anticipation of future demands.  FIG. 8E  assumes a system having a 200 minute look ahead window. Such a look ahead window is chosen to facilitate an explanation of the system and should not be viewed in a limiting sense. Beginning at the end of the window (200 minutes), the system determines the power/energy demands at any given point in time. If the determined demand exceeds the prime mover&#39;s capacity or limit, the system continues back and determines opportunities when energy can be stored, in advance of the determined excess demand period, and ensures that sufficient energy is stored during such opportunities. 
   Although  FIGS. 6A-D ,  7 A-D, and  8 A-E have been separately described, it should be understood that the systems reflected therein could be embodied in a single energy management system. Further, the look ahead energy storage and transfer capability described above could be accomplished dynamically or in advance. For example, in one form, an energy management processor (see  FIG. 5 ) is programmed to compare the vehicle&#39;s present position with upcoming track/course characteristics in real or near real time. Based on such dynamic determinations, the processor then determines how to best manage the energy capture and storage capabilities associated with the vehicle in a manner similar to that described above with respect to  FIGS. 7A-D  and  8 A-E. In another form, such determinations are made in advance. For example, an off-vehicle planning computer may be used to plan a route and determine energy storage and transfer opportunities based on a database of known course information and projected conditions such as, for example, vehicle speed, weather conditions, and the like. Such pre-planned data would thereafter be used by the energy management system to manage the energy capture and storage process. Look ahead planning could also be done based on a route segment or an entire route. 
   It should further be understood that the energy management system and methods described herein may be put into practice with a variety of vehicle configurations. For example, such systems and methods could be practiced with a locomotive having a separate energy tender vehicle housing the energy capture and storage medium. As another example, the energy management systems and methods herein described could be employed with a locomotive having a separate energy tender vehicle that employs its own traction motors. In another example, the energy management systems and methods described herein may be employed as part of an off-highway vehicle, such as a locomotive, in which the energy storage medium is included as part of the vehicle itself. Other possible embodiments and combinations should be appreciated from the present disclosure and need not be recited in additional detail herein. 
     FIGS. 9A-9G  are electrical schematics illustrating several different embodiments of an electrical system suitable for use in connection with a hybrid energy locomotive. In particular, the exemplary embodiments illustrated in these figures relate to a hybrid energy diesel-electric locomotive system. It should be understood that the embodiments illustrated in  FIGS. 9A-9G  could be incorporated in a plurality of configurations, including those already discussed herein (e.g., a locomotive with a separate energy tender vehicle, a locomotive with a self-contained hybrid energy system, an autonomous tender vehicle, and the like). 
     FIG. 9A  illustrates an electrical schematic of a locomotive electrical system having an energy capture and storage medium suitable for use in connection with aspects of the systems and methods disclosed herein. The particular energy storage element illustrated in  FIG. 9A  comprises a battery storage  902 . The battery storage  902  is preferably connected directly across the traction bus (DC bus  122 ). In this exemplary embodiment, an auxiliary power drive  904  is also connected directly across DC bus  122 . The power for the auxiliaries is derived from DC bus  122 , rather than a separate bus. 
   It should be appreciated that more than one type of energy storage element may be employed in addition to battery storage  902 . For example, an optional flywheel storage element  906  can also be connected in parallel with battery storage  902 . The flywheel storage  906  shown in  FIG. 9A  is preferably powered by an AC motor or generator connected to DC bus  122  via an inverter or converter. Other storage elements such as, for example, capacitor storage devices (including ultra-capacitors) and additional battery storages (not shown) can also be connected across the DC bus and controlled using choppers and/or converters and the like. It should be understood that although battery storage  902  is schematically illustrated as a single battery, multiple batteries or battery banks may likewise be employed. 
   In operation, the energy storage elements (e.g., battery storage  902  and/or any optional energy storage elements such as flywheel  906 ) are charged directly during dynamic braking operations. Recall that, during dynamic braking, one or more of the traction motor subsystems (e.g.,  124 A- 124 F) operate as generators and supply dynamic braking electric power which is carried on DC bus  122 . Thus, all or a portion of the dynamic braking electric power carried on DC bus  122  may be stored in the energy storage element because the power available on the bus exceeds demand. When the engine is motoring, the battery (and any other optional storage element) is permitted to discharge and provide energy to DC bus  122  that can be used to assist in driving the traction motors. This energy provided by the storage element may be referred to as secondary electric power. Advantageously, because the auxiliaries are also driven by the same bus in this configuration, the ability to take power directly from DC bus  122  (or put power back into bus  122 ) is provided. This helps to minimize the number of power conversion stages and associated inefficiencies due to conversion losses. It also reduces costs and complexities. 
   It should be appreciated that the braking grids may still be used to dissipate all or a portion of the dynamic braking electric power generated during dynamic braking operations. For example, an energy management system is preferably used in connection with the system illustrated in  FIG. 9A . Such an energy management system is configured to control one or more of the following functions: energy storage; stored energy usage; and energy dissipation using the braking grids. It should further be appreciated that the battery storage (and/or any other optional storage element) may optionally be configured to store excess prime mover electric power that is available on the traction bus. 
   Those skilled in the art should appreciate that certain circumstances preclude the operation of a diesel engine when the locomotive and/or train need to be moved. For example, the engine may not be operable. As another example, various rules and concerns may prevent the operation of the engine inside buildings, yards, maintenance facilities, or tunnels. In such situations, the train is moved using stored battery power. Advantageously, various hybrid energy locomotive configurations disclosed herein permit the use of stored power for battery jog operations directly. For example, the battery storage  902  of  FIG. 9A  can be used for battery jog operations. Further, the prior concept of battery jog operations suggests a relatively short time period over a short distance. The various configurations disclosed herein permit jog operations for much longer time periods and over much longer distances. 
     FIG. 9B  illustrates a variation of the system of  FIG. 9A . A primary difference between  FIGS. 9A and 9B  is that the system shown in  FIG. 9B  includes chopper circuits DBC 1  and DBC 2  connected in series with the braking grids. The chopper circuits DBC 1  and DBC 2  allow fine control of power dissipation through the grids that, therefore, provides greater control over the storage elements such as, for example, battery storage  902 . In one embodiment, chopper circuits DBC 1  and DBC 2  are controlled by an energy management system (see  FIG. 5 ). It should also be appreciated that chopper circuits DBC 1  and DBC 2 , as well as any optional storage devices added to the circuit (e.g., flywheel storage  906 ), could also be used to control transient power. 
   In the configuration of  FIG. 9A , the dynamic braking contactors (e.g., DB 1 , DB 2 ) normally only control the dynamic braking grids in discrete increments. Thus, the power flowing into the grids is also in discrete increments (assuming a fixed DC voltage). For example, if each discrete increment is 1000 h.p., the battery storage capability is 2000 h.p., and the braking energy returned is 2500 h.p., the battery cannot accept all of the braking energy. As such, one string of grids is used to dissipate 1000 h.p., leaving 1500 h.p. for storage in the battery. By adding choppers DBC 1 , DBC 2 , the power dissipated in each grid string can be more closely controlled, thereby storing more energy in the battery and improving efficiency. In the foregoing example, choppers DBC 1  and DBC 2  can be operated at complementary 50% duty cycles so that only 500 h.p. of the braking energy is dissipated in the grids and 200 h.p. is stored in the battery. 
     FIG. 9C  is an electrical schematic of a locomotive electrical system illustrating still another configuration for implementing an energy storage medium. In contrast to the systems illustrated in  FIGS. 9A and 9B , the battery storage  902  of  FIG. 9C  is connected to DC bus  122  by way of a dc-to-dc converter  910 . Such a configuration accommodates a greater degree of variation between DC bus  122  voltage and the voltage rating of battery storage  902 . Multiple batteries and/or DC storage elements (e.g., capacitors) could be connected in a similar manner. Likewise, chopper control, such as that illustrated in  FIG. 9B  could be implemented as part of the configuration of  FIG. 9C . It should be further understood that the dc-to-dc converter  910  may be controlled via an energy management processor (see  FIG. 5 ) as part of an energy management system and process that controls the storage and regeneration of energy in the energy storage medium. 
   In operation, the electric power carried on DC bus  122  is provided at a first power level (e.g., a first voltage level). The dc-to-dc converter  910  is electrically coupled to DC bus  122 . The dc-to-dc converter  910  receives the electric power at the first power level and converts it to a second power level (e.g., a second voltage level). In this way, the electric power stored in battery storage  902  is supplied at the second power level. It should be appreciated that the voltage level on DC bus  122  and the voltage supplied to battery storage  902  via dc-to-dc converter  910  may also be at the same power level. The provision of dc-to-dc converter  910 , however, accommodates variations between these respective power levels. 
     FIG. 9D  is an electrical schematic of a locomotive electrical system that is similar to the system shown in  FIG. 9C . One difference between these systems is that the auxiliary power subsystem  904  reflected in  FIG. 9D  is connected to DC bus  122  via a pair of dc-to-dc converters  912  and  914 . Such a configuration provides the advantage of allowing the use of existing, lower voltage auxiliary drives and/or motor drives having low insulation. On the other hand, in this configuration, the auxiliary power traverses two power conversion stages. It should be understood that although  FIG. 9D  illustrates the auxiliaries as consuming power all of the time—not regenerating—bi-directional dc-to-dc converters can also be used in configurations in which it is desirable to have the auxiliaries regenerate power (see, for example,  FIG. 9G ). These dc-to-dc converters  912  and  914  are preferably controlled via an energy management system that controls the storage and regeneration of energy in the energy storage medium. 
     FIG. 9E  illustrates, in electrical schematic form, still another configuration of an energy storage medium. Unlike the examples illustrated in  FIGS. 9A-9D , however, the configuration of  FIG. 9E  includes a separate DC battery bus  922 . The separate battery bus  922  is electrically isolated from main DC bus  122  (the traction bus) by a dc-to-dc converter  920  (also referred to as a two-stage converter). Accordingly, the power flow between the traction bus (DC bus  122 ), the energy storage elements, and the auxiliaries preferably passes through the bi-directional dc-to-dc converter  920 . In the configuration of  FIG. 9E , any additional storage elements (e.g., flywheels, capacitors, and the like) are preferably connected across the DC battery bus  922 , rather than across the main DC bus  122 . The dc-to-dc converter  920  may be controlled via an energy management system that controls the storage and regeneration of energy in the energy storage medium. 
     FIG. 9F  reflects a variation of the configuration of  FIG. 9E . In the configuration of  FIG. 9F , any variable voltage storage elements (e.g., capacitors, flywheels, and the like) that are used in addition to battery  906  are connected directly across main DC bus  122  (the traction bus). However, battery  906  remains connected across the isolated DC battery bus  922 . Advantageously, in this configuration dc-to-dc converter  920  matches the voltage level of battery storage  902  but avoids two conversions of large amounts of power for the variable voltage storage elements. Like the other configurations, the configuration of  FIG. 9F  may be implemented in connection with an energy management system that oversees and controls the storage and regeneration of energy in the energy storage medium. 
     FIG. 9G  reflects a variation of the configuration of  FIG. 9F  in which only the auxiliaries are connected to a separate auxiliary bus  930  through two-stage converter  920 . Accordingly, electric power carried on DC bus  122  is provided at a first power level and power carried on the auxiliary bus  930  is provided at a second power level. The first and second power levels may or may not be the same. 
     FIGS. 10A-10C  are electrical schematics that illustrate additional embodiments, including embodiments particularly suited for modifying existing AC diesel-electric locomotives to operate in accordance with aspects of the present disclosure. It should be understood, however, that the configurations illustrated and described with respect to  FIGS. 10A-10C  are not limited to retrofitting existing diesel-electric locomotives. 
     FIG. 10A  illustrates a variation of the embodiment illustrated in  FIG. 9C . The embodiment of  FIG. 10A  uses only battery storage devices and does not include a non-battery storage, such as optional flywheel storage  906 . In particular,  FIG. 10A  illustrates an embodiment having a converter  1006  (e.g., a dc-to-dc converter) connected across DC bus  122 . A battery storage element  1002  is connected to the converter  1006 . Additional converters and battery storage elements may be added to this configuration in parallel. For example, another converter  1008  may be connected across DC bus  122  to charge another battery storage element  1004 . One of the advantages of the configuration of  FIG. 10A  is that it facilitates the use of multiple batteries (or battery banks) having different voltages and/or charging rates. 
   In certain embodiments, power transfer between energy storage devices is facilitated. The configuration of  FIG. 10A , for instance, allows for energy transfer between batteries  1002  and  1004  via the DC bus  122 . For example, if, during motoring operations, the engine (prime mover) supplies 2000 h.p. of power to the dc traction bus, the traction motors consume 2000 h.p., and battery  1002  supplies 100 h.p. to the traction bus (via converter  1006 ), the excess 100 h.p. is effectively transferred from battery  1002  to battery  1004  (less any normal losses). 
   The configuration illustrated in  FIG. 10B  is similar to that of  FIG. 10A , except that it uses a plurality of converters (e.g., converters  1006 ,  1008 ) connected to the DC bus  122  to supply a common battery  1020  (or a common battery bank). One of the advantages of the configuration of  FIG. 10B  is that it allows the use of relatively smaller converters. This may be particularly advantageous when retrofitting an existing locomotive that already has one converter. A similar advantage of this configuration is that it allows the use of higher capacity batteries. Still another advantage of the configuration of  FIG. 10B  is that it permits certain phase shifting operations, thereby reducing the ripple current in the battery and allowing the use of smaller inductors (not shown). For example, if converters  1006  and  1008  are operated at 1000 Hz, 50% duty cycles, and the duty cycles are selected such that converter  1006  is on while converter  1008  is off, the converter effect is as if a single converter is operating at 2000 Hz, which allows the use of smaller inductors. 
     FIG. 10C  an electrical schematic illustrating another embodiment that is particularly well-suited for retrofitting an existing diesel-electric locomotive to operate as a hybrid energy locomotive. The configuration of  FIG. 10C  uses a double set of converters  1006 ,  1030  and one or more batteries  1020  (of the same or different voltage levels). An advantage of the system depicted in  FIG. 10C  is that the battery  1020  can be at a higher voltage level than the DC bus  122 . For example, if the converters  1006 ,  1008  illustrated in  FIGS. 10A and 10B  are typical two quadrant converters, they will also have freewheeling diodes associated therewith (not illustrated). If the voltage of battery  1002 ,  1004  ( FIG. 10A ), or  1020  ( FIG. 10B ) exceeds the DC bus voltage, the battery will discharge through the freewheeling diode. A double converter, such as that illustrated in  FIG. 10C , avoids this situation. One advantage of this capability is that the voltage level on the DC bus can be modulated to control power to the dynamic braking grids independently. 
     FIG. 11  is an electrical schematic that illustrates one preferred way of connecting electrical storage elements. In particular,  FIG. 11  illustrates an electrical schematic of a system that may be used for retrofitting a prior art diesel-electric locomotive to operate as a hybrid energy locomotive, or for installing a hybrid energy system as part of the original equipment during the manufacturing process. The embodiment illustrated assumes an AC diesel-electric locomotive with six axles. Each axle is driven by an individual traction motor subsystem. One such AC locomotive is the AC4400, available from the assignee of the present invention. 
   Typically, the converter/motor system have extra capability (e.g., power capacity) available in the majority of operating conditions. Such extra capability may be due to lower actual ambient conditions, as compared with the design criteria. For example, some locomotives are designed to operate in ambient temperatures of up to 60 degrees Celsius, which is well above typical operating conditions. Considerations other than thermal conditions may also result in extra capacity during significant operating periods. In a typical diesel-electric locomotive, for instance, the use of all of the traction motors may only be required for low speed and when the locomotive operates in an adhesion limited situation (poor rail conditions). In such case, the weight on the driven axles determines the pulling power/tractive effort. Hence, all axles/motors need to be driven to obtain maximum tractive effort. This can be especially true if the train is heavily loaded during poor rail conditions (snowy or slippery). Such conditions are normally present for only a fraction of the locomotive operating time. During the majority of the operating time, all of the traction motors/inverters are not fully utilized to supply tractive effort. Thus, for example, when retrofitting an existing prior art locomotive, or manufacturing a new locomotive, it is possible to take advantage of this partial underutilization of the traction motors/inverters. 
   By way of a specific example, the embodiment of  FIG. 11  configured such that one of the six traction motor subsystems is connected to the energy storage element  1102 , through a transfer switch  1104  and a plurality of inductors  1110 . More particularly, the traction motor subsystem  124 F includes an inverter  106 F and a traction motor  1108 F. Such a configuration is suited for retrofitting a single axle of an existing prior art diesel-electric locomotive. It should be understood that retrofitting a typical prior art diesel-electric locomotive requires the addition of power conversion equipment and associated cooling devices. The space available for installing the retrofit equipment, however, is generally limited. Therefore, one of the advantages of the “single-axle” configuration of  FIG. 11  is that it tends to minimize impacts and makes retrofitting a more viable option. Similar advantages, however, may also be enjoyed when the hybrid energy system is installed as original equipment during manufacturing. 
   The transfer switch  1104  preferably comprises a three-phase set of contactors or a set of motorized contacts (e.g., bus bars) that connect inverter  106 F to traction motor  1108 F when all of the axles are needed, and connects inverter  106 F to inductors  1110  and battery  1102  when battery charging or discharging is desired. Thus, transfer switch  1104  has a first connection state and a second connection state. In the first connection state, transfer switch  1104  connects inverter  106 F to traction motor  1108 F. In the second connection state, transfer switch connects inverter  106 F to battery  1102 . 
   Transfer switch  1104  is preferably controlled by a switch controller  1120 . In one form, the switch controller  1120  is a manual operator-controlled switch that places transfer switch  1104  into the first or the second connection state. In another form, the switch controller reflects control logic that controls the connection state of transfer switch  1104  in accordance with a preferred operating scheme. Table I (below) is indicative of one such preferred operating scheme. Other schemes are possible. 
   
     
       
         
             
             
           
             
               TABLE I 
             
             
                 
             
             
               Five Axles 
               Six Axles 
             
             
                 
             
           
          
             
               Low Speed And Low Tractive 
               Battery Fully Charged &amp;  Dynamic 
             
             
               Effort Settings 
               Braking 
             
             
               High Speed Motoring 
               No Battery Charging &amp;  Motoring 
             
             
                 
               Battery Discharged &amp;  Motoring 
             
             
                 
               Very High Speed Dynamic Braking 
             
             
                 
             
          
         
       
     
   
   Although  FIG. 11  illustrates a three-phase connection between battery  1102  and transfer switch  1104 , it is not necessary that all three phases be used. For example, if the power requirement is relatively low, only one or two phases may be used. Similarly, three separate batteries could be independently connected (one to each phase), or one large battery could be connected to two phases, with a relatively smaller battery connected to the third phase. Further, power transfer between multiple batteries having different voltage potentials and/or capacities is also possible. 
   The configuration of  FIG. 11  is especially advantageous in the context of retrofitting existing locomotives because transfer switch  1104  is believed to be much less expensive than adding additional inverters and/or dc-to-dc converters. Such advantage, however, is not limited to the retrofit context. Also, it should be understood that the configuration of  FIG. 11  is not limited to a single inverter per transfer switch configuration. 
     FIG. 11  further illustrates an optional charging source  1130  that may be electrically connected to DC traction bus  122 . The charging source  1130  may be, for example, another charging engine (see  FIG. 3 ) or an external charger, such as that discussed in connection with  FIG. 5 . 
   The general operation of the configuration of  FIG. 11  will be described by reference to the connection states of transfer switch  1104 . When transfer switch  1104  is in the first switch state, the sixth axle is selectively used to provide additional motoring or braking power. In this switch state, battery  1102  is effectively disconnected and, therefore, neither charges nor discharges. 
   When the sixth axle is not needed, switch controller  1120  preferably places transfer switch  1104  in the second connection state-battery  1102  is connected to inverter  106 F. If, at this time, the other traction motors (e.g., traction motor  108 A) are operating in a dynamic braking mode, electrical energy is generated and carried on DC traction bus  122 , as described in greater detail elsewhere herein. Inverter  106 F transfers a portion of this dynamic braking electrical energy to battery  1102  for storage. If, on the other hand, the other traction motors are operating in a motoring mode, inverter  106 F preferably transfers any electrical energy stored in battery  1102  onto DC traction bus  122  to supplement the primary electric power supplied by prime mover power source  104 . Such electrical energy transferred from battery  1102  to DC traction bus  122  may be referred to as secondary electric power. In one preferred embodiment, inverter  106 F comprises a chopper circuit for controlling the provision of secondary electric power to DC traction bus  122  from battery  1102 . 
   It should be understood, however, that battery  1102  can also be charged when the other traction motors are not operating in a dynamic braking mode. For example, the battery can be charged when transfer switch  1104  is in the second connection state (battery  1102  is connected to inverter  106 F) and the other traction motors are motoring or idling if the amount of power drawn by the other traction motors is less than the amount of primary electric power carried on DC traction bus  122 . 
   Advantageously, battery  1102  can also be charged using charging electric power from optional energy source  1130 . As illustrated in  FIG. 11 , optional energy source  1130  is preferably connected such that it provides charging electric power to be carried on DC traction bus  122 . When optional energy source  1130  is connected and providing charging electric power, switch controller  1120  preferably places transfer switch  1104  in the second connection state. In this configuration, inverter  106 F transfers a portion of the electric power carried on DC traction bus  122  to battery  1102  for storage. As such, battery  1102  may be charged from optional energy source  1130 . 
   In summary, in the embodiment of  FIG. 11 , when transfer switch is in the second connection state, battery  1102  may be charged from dynamic braking energy, from excess locomotive energy (i.e., when the other traction motors draw less power than the amount of primary electric power carried on DC traction bus  122 ), and/or from charging electric power from optional charging source  1130 . When transfer switch  1104  is in the second connection state and the other traction motors draw more power than the amount of primary electric power carried on DC traction bus  122 , inverter  106 F transfers secondary electric power from battery  1102  to DC traction bus  122  to supplement the primary electric power. When transfer switch  1104  is in the first connection state, battery  1102  is disconnected and traction motor  1108 F is operable to assist in motoring and/or dynamic braking. Table I summarizes one set of operating modes of the embodiment of  FIG. 11 . 
   While  FIG. 11  illustrates an energy storage device in the form of a battery, other energy storage devices, such as flywheel systems or ultra-capacitors, may also be employed instead of or in addition to battery  1102 . Further, it should be understood that the configuration of  FIG. 11  may be scaled. In other words, the configuration can be applied to more than one axle. 
     FIG. 12  is a flow chart that illustrates one method of operating a hybrid energy locomotive system. The particular method illustrated relates to a system including a locomotive vehicle and an energy tender vehicle. The locomotive includes a diesel-electric prime mover power source that supplies primary electric power to a plurality of traction motor systems associated with the locomotive. As explained elsewhere herein, the traction motor systems operate the locomotive in a motoring mode in response to the primary electric power. In this particular example, the energy tender also includes a plurality of traction motor systems (see  FIG. 2 ). The energy tender traction motor systems are operable in both a motoring mode and a dynamic braking mode. The energy tender vehicle also includes an energy storage system for capturing at least a portion of the electrical energy generated when the energy tender traction motors operate in the dynamic braking mode. 
   At blocks  1202  and  1204 , primary electric power is supplied to one or more of the locomotive traction motor systems, thereby causing the locomotive to operate in a motoring mode. When the locomotive traction motor systems operate in the motoring mode, it is possible to operate one or more of the energy tender traction motor systems in a dynamic braking mode, as shown by block  1206 . Of course, the energy tender traction motor systems can be operated in the dynamic braking mode at other times such as, for example, when the locomotive traction motor systems operate in the dynamic braking mode. As shown at blocks  1208  and  1210 , when one or more of the energy tender traction motor systems operate in the dynamic braking mode, electrical energy is generated. Some of the dynamic braking energy is preferably stored in the energy storage system for later use. For example, such stored power may be converted and supplied as secondary electric power for use by the energy tender traction motor systems to assist in motoring, as shown by block  1212 . 
   Advantageously, the method of  FIG. 12  permits locating the energy tender vehicle anywhere in the train because the energy tender vehicle can capture dynamic braking energy from its own traction motor systems. In other words, the energy capture system need not be electrically connected to the locomotive in order to store energy for later use. 
   Although the foregoing descriptions have often referred to AC diesel-electric locomotive systems to describe several pertinent aspects of the disclosure, the present invention should not be interpreted as being limited to such locomotive systems. For example, aspects of the present disclosure may be employed with “all electric” locomotives powered by electric “third rails” or overhead power systems. Further, aspects of the hybrid energy locomotive systems and methods described herein can be used with diesel-electric locomotives using a DC generator rather than an AC alternator and combinations thereof. Also, the hybrid energy locomotive systems and methods described herein are not limited to use with AC traction motors. As explained elsewhere herein, the energy management system disclosed herein may be used in connection with non-locomotive off-highway vehicles such as, for example, large excavators. 
   As can now be appreciated, the hybrid energy systems and methods herein described provide substantial advantages over the prior art. Such advantages include improved fuel efficiency, increased fuel range, and reduced emissions such as transient smoke. Other advantages include improved speed by the provision of an on-demand source of power for a horsepower burst. Such a system also provides improved tunnel performance such as, for example, improved immunity to oxygen and/or temperature deviations in tunnels. Also among the advantages are reduced noise and vibration conditions, which may be particularly beneficial to personnel who work on the train. Significantly, the hybrid energy locomotive system herein described may also be adapted for use with existing locomotive systems. 
     FIG. 13  illustrates an exemplary embodiment of an energy management system  502 ′ for use with one of a plurality of hybrid energy diesel electric locomotives  100 ′. Each locomotive  100 ′ includes an engine  102 ′ and power converter  104 ′,  106 ′ to provide primary electric power. Additionally, the locomotive  100 ′ illustratively includes a traction bus  108 ′ coupled to the power converter  104 ′,  106 ′ to carry the primary electric power, and a traction motor  108 ′ connected to the traction bus. The traction motor  108 ′ includes a motoring mode responsive to the primary electric power to propel one of a plurality of locomotives  100 ′ on one of the plurality of routes. Additionally, the traction motor  108 ′ includes a dynamic braking mode to generate dynamic braking electrical energy on the traction bus. 
   As illustrated in the exemplary embodiment of  FIG. 13 , the energy management system  502 ′ includes a position identification device  510 ′, such as a GPS system, for example, to provide position information for one of the plurality of locomotives  100 ′ at incremental positions  518 ′ along one of the plurality of routes. Additionally, the exemplary embodiment of the energy management system  502 ′ illustratively includes a database  508 ′ to store historical data of a traction and/or auxiliary energy demand for a plurality of locomotives  100 ′ at each of the incremental positions  518 ′ along each of the plurality of routes. Each of the locomotives  100 ′ whose previous traction and/or auxiliary energy demand along each of the plurality of routes is stored in the database  508 ′ may differ in size, length, engine horsepower output, in addition to other operating characteristics. Additionally, each of the plurality of routes may differ substantially in their path or may include substantially common paths. 
   More particularly, the energy management system  502 ′ includes an energy management processor  506 ′ coupled to the position identification device  510 ′ and the database  508 ′ to retrieve historical data  512 ′,  514 ′,  516 ′ for a plurality of locomotives  100 ′ at each of the incremental positions  518 ′ along one of a plurality of routes. The historical data  512 ′,  514 ′,  516 ′ illustrated in the exemplary embodiment of  FIG. 14  may represent three independent historical data sets of the traction and/or auxiliary energy demand for the same locomotive traveling over the same route, or alternatively may represent three independent historical data sets of the traction and/or auxiliary energy demand for three distinct locomotives traveling over the same route. The energy management processor  506 ′ retrieves the historical data  512 ′,  514 ′,  516 ′ of traction and/or auxiliary energy demand to estimate an anticipated traction and/or auxiliary energy demand  520 ′ ( FIG. 17 ) for one of the plurality of locomotives  100 ′ at each of the incremental positions  518 ′ along the same route over which the historical data was obtained.  FIG. 17  illustrates an exemplary embodiment of an anticipated traction and/or auxiliary energy demand  520 ′ obtained using the historical data  512 ′,  514 ′,  516 ′ of traction and/or auxiliary energy demand, with  FIG. 17  illustrating a portion of the incremental positions of  FIG. 14  approximately between positions  10  and  80 , for example. The energy management processor  506 ′ utilizes the historical data  512 ′,  514 ′,  516 ′ with a variety of different methods to determine an anticipated traction and/or auxiliary energy demand for one of the plurality of locomotives  100 ′ to travel over the same route, as discussed in further detail below. Although  FIG. 14  illustrates three sets of historical data utilized to obtain the anticipated traction and/or auxiliary energy demand of the locomotive to travel on a route, less than three or more than three sets of historical data may be utilized to obtain the anticipated traction and/or auxiliary energy demand at each fixed location along the route, and to estimate the storage and transfer parameters, as discussed below. 
   As further illustrated in the exemplary embodiment of  FIG. 13 , the energy management system  502 ′ illustratively includes an energy storage system  204 ′ connected to the traction bus  108 ′. The energy storage system  204 ′ is responsive to the energy management processor  506 ′ at each incremental position  518 ′ along each route based upon the position information from the position identification device  510 ′, to store electrical energy generated by the traction motor  108 ′ based upon a storage parameter. Additionally, the energy storage system  204 ′ is responsive to the energy management processor  506 ′ at each incremental position  518 ′ to supply secondary electric power from the stored electrical energy to the traction bus to augment the primary electric power based upon a transfer parameter so to enhance a performance parameter of one of the plurality of locomotives  100 ′ over one of the plurality of routes. In one embodiment of the energy management system  502 ′, the storage parameters and transfer parameters are communicated from the energy management processor  506 ′ to the energy storage system  204 ′ at each incremental position  518 ′ along each of the plurality of routes. In one embodiment of the energy management system  502 ′, the energy storage system  204 ′ supplies secondary electric power based upon the transfer parameter so to minimize a fuel efficiency of one of the plurality of locomotives  100 ′ over one of the plurality of routes. However, the energy management system  502 ′ may include the energy storage system  204 ′ to supply secondary electric power to enhance a performance parameter of one of the plurality of locomotives other than minimizing the fuel efficiency over one of the plurality of routes, for example. 
   The energy management processor  506 ′ utilizes the anticipated traction and/or auxiliary energy demand of one of the plurality of locomotives  100 ′ at each of the incremental positions  518 ′, determined using the historical data  512 ′,  514 ′,  516 ′, with a current status  522 ′ ( FIG. 17 ) of the energy storage system at each of the incremental positions to estimate a storage and transfer parameter at each of incremental positions.  FIG. 17  illustrates an exemplary embodiment of a current status or battery energy, for example, of the energy storage system versus incremental position along the route. The energy management processor  506 ′ will determine whether to increase or decrease the storage/transfer parameter from the initial current status  522 ′ of the energy storage system  204 ′ at an initial incremental position of the route using the anticipated traction and/or auxiliary energy demand, as discussed below. 
   Upon retrieving the traction and/or auxiliary energy demand of each locomotive  100 ′ at each incremental location  518 ′ along each route, the energy management processor  506 ′ segregates the traction and/or auxiliary energy demand values for the plurality of locomotives  100 ′ into a plurality of groups  526 ′ ( FIG. 15 ) based upon one fixed location corresponding to incremental positions  518 ′ along each route. In the exemplary embodiment of  FIG. 15 , the energy management processor has segregated twenty-three traction and/or auxiliary energy demand values for the plurality of locomotives at mile marker 70, for example, of one particular route of the plurality of routes. Although  FIG. 15  illustrates twenty-three traction and/or auxiliary energy demand values for a plurality of locomotives at mile marker 70 of a particular route, the energy management processor may segregate more or less than twenty-three traction and/or auxiliary energy demand values, it may segregate traction and/or auxiliary energy demand values for the same locomotive at a fixed location along the same route, and it may store, retrieve and segregate traction and/or auxiliary energy demand values at various incremental positions, such as every 10 mile marker, or at any other varying incremental positions. In addition, although the energy management processor segregates the traction motor energy values based upon a fixed location of the locomotives along the route, it may segregate the traction motor energy values based upon fixed time increments. In an exemplary embodiment of the energy management system,  FIG. 14  may represent the traction and/or auxiliary energy values at each one of a fixed time increment, such as every 10 minute increment from the commencement of a trip, for example. In this exemplary embodiment,  FIG. 15  correspondingly illustrates the segregation of the traction and/or auxiliary energy values by the energy management processor at each fixed time increment, such as 70 minutes from commencement of the trip, for example, and the twenty-three traction and/or auxiliary energy values at each of the respective twenty-three runs, for example. Stationary application aspects of the present invention are applicable to an exemplary embodiment featuring an anticipated traction and/or auxiliary energy value at each of a fixed time increment, determined based upon historical data of traction and/or auxiliary energy at fixed time increments. 
   The energy management processor  506 ′ estimates an anticipated traction and/or auxiliary energy demand  520 ′ of one of the plurality of locomotives  100 ′ at each fixed location  518 ′ along the route based upon each of the groups  526 ′ of the traction and/or auxiliary energy demand values of the plurality of locomotives  100 ′. Additionally, the energy management processor  506 ′ determines the anticipated traction and/or auxiliary energy demand of one of plurality of locomotives  100 ′ at each of the fixed locations based upon one or more operating characteristics of the locomotive  100 ′ at each of the fixed locations  518 ′. Upon originally storing each of the historical data  512 ′,  514 ′,  516 ′ of the traction and/or auxiliary energy demand of each locomotive  100 ′ along each route, the database  508 ′ may store the operating characteristics, including weight, speed, and length, for example, of each locomotive at each incremental position. This historical data  512 ′,  514 ′,  516 ′, which may include the operating characteristics of each locomotive at each incremental position, in addition to the traction and/or auxiliary energy demand, may be used by the energy management processor  506 ′ to derive a mathematical relationship between the anticipated traction and/or auxiliary energy demand  520 ′ of one of the plurality of locomotives  100 ′ along the route at each fixed location  518 ′, and one or more operating characteristics, including but not limited to weight, speed and length of the locomotive, for example. The energy management processor  506 ′ may utilize the known operating characteristics and/or projected operating characteristics, such as speed, for example, to determine an anticipated traction and/or auxiliary energy demand  520 ′ at each fixed location  518 ′, and thus incremental position  518 ′ along the route. In an exemplary embodiment, such a mathematical relationship may be:
 
 ED =(1.1* W )+(23* S )+{207,392,−102}−(170* L )+ R  
 
   where ED is the anticipated traction and/or auxiliary energy demand at the fixed location (or fixed time) when the weight, speed and length measurements were taken, W is the weight of the locomotive (in tons), S is the speed of the locomotive (in miles per hour), L is the length of the locomotive (in feet), and R is a residual term. The type of locomotive will determine the term {207,392,−107} to be used, based upon on one of an intermodal (or high speed freight) type locomotive corresponding to 207, a coal (or low speed freight) type locomotive corresponding to 392 and a manifest (or passenger) type locomotive corresponding to −102. The first four terms of the above equation consider the current weight, speed, type and length of the locomotive (ie. static conditions), and the residual R factor considers previous history of the locomotive operation in performing future calculations of anticipated traction and/or auxiliary energy demand values at fixed location increments or fixed time increments. In an exemplary embodiment, the residual factor R is determined based upon the energy management processor evaluating the relative magnitude of the anticipated traction and/or auxiliary energy demand for previous fixed location increments or fixed time increments as compared to the historic data of traction and/or auxiliary energy demand at those fixed location increments or fixed time increments. For example, if the energy management processor determines that the anticipated traction and/or auxiliary energy demand for the previous two 10 mile marker increments was 50% of the maximum historic data of traction and/or auxiliary energy demand for those previous two 10 mile maker increments, the energy management processor may derive a residual factor R to adjust the anticipated traction and/or auxiliary energy demand to correspond to 50% of the maximum historic data for future increment positions. In an additional exemplary embodiment, the energy management processor may derive the residual factor R based upon comparing previously anticipated traction and/or auxiliary energy demands with actual measured traction and/or auxiliary energy demands at previous fixed location increments or fixed time increments. For example, if the energy management processor determines that the anticipated traction and/or auxiliary energy demands for the previous three 10 mile marker increments were 30% higher than the actual traction and/or auxiliary energy demands measured as the locomotive traversed through those previous three 10 mile marker increments, the energy management process may derive a residual factor R to scale down future anticipated traction and/or auxiliary energy demands to more closely approximate the actual traction and/or auxiliary energy demands. Various mathematical relationships between the anticipated traction and/or auxiliary energy demand of one of the plurality of locomotives  100 ′ and one or more operating characteristics other than the mathematical relationship above may be utilized. 
   In addition, the energy management processor  506 ′ may utilize the groups  526 ′ of traction and/or auxiliary energy demand values at each fixed location  518 ′ to determine the anticipated traction and/or auxiliary energy demand for one of a plurality of locomotives  100 ′ at each fixed location  518 ′. The energy management processor  506 ′ may perform a statistical computation of each group  526 ′ of traction and/or auxiliary energy demand values at each fixed location  518 ′ along the route for the plurality of locomotives  100 ′. In an exemplary embodiment of the energy management system, such statistical computations may include an average, mean and range of each group  526 ′ of traction and/or auxiliary energy demand values at each fixed location  518 ′ along the route for the plurality of locomotives  100 ′. For example, in an exemplary embodiment, for a group of traction and/or auxiliary energy demand values ranging from 1000-4000 HP, the average may be 2300 HP, the mean may be 2400 HP and the range of 3000 HP may be utilized by halving it (1500) and adding this to the minimum value (1000), to obtain 2500 HP. Thus, in an exemplary embodiment, the energy management processor  506 ′ may utilize any of these statistical computations (in addition to others) in order to determine an anticipated traction and/or auxiliary energy demand for that particular fixed location  518 ′ of the incremental positions along the route. As stated above, the energy management processor  506 ′ may alternatively derive a mathematical relationship involving the operating characteristics of the locomotive to determine an anticipated traction and/or auxiliary energy demand for that each particular fixed location along the route. 
   As illustrated in the exemplary embodiment of  FIG. 16 , the current system for determining anticipated traction and/or auxiliary energy demand by analyzing track topographic information is displayed.  FIG. 17  is an exemplary embodiment of an energy management system including an energy management processor  506 ′ to determine a traction and/or auxiliary energy demand curve  520 ′ based upon a statistical computation at each fixed location  518 ′ of the incremental positions along a route. 
   After determining an anticipated traction and/or auxiliary energy demand  520 ′ for one of the plurality of locomotives  100 ′ at each fixed location  518 ′ of the incremental positions along the route, utilizing one of the mathematical relationship with the operating characteristics or the statistical computations, as discussed above, the energy management processor  506 ′ estimates the storage parameter and transfer parameter at each fixed location  518 ′ of the incremental position along the route. The energy management processor  506 ′ estimates the storage parameter and transfer parameter at each fixed location  518 ′ of the incremental position along the route by utilizing the anticipated traction and/or auxiliary energy demand  520 ′ at each fixed location and monitoring a current status  522 ′ of the energy storage system  204 ′ at each fixed location along the route. As illustrated in the exemplary embodiment of  FIG. 17 , the energy management processor  506 ′ estimates a storage parameter at a fixed location d 1  due to an upcoming anticipated traction and/or auxiliary energy demand at fixed location d 2  which exceeds the maximum primary energy of the locomotive engine. The storage parameter is reflected in  FIG. 17  at fixed distance d 1  by the increase in the energy  522 ′ of the energy storage system  204 ′, in anticipation of a future energy need based upon the anticipated traction and/or auxiliary energy demand at fixed location d 2 . For example, if the maximum primary energy from the locomotive engine is 2000 HP and an upcoming anticipated traction and/or auxiliary energy demand is 2500 HP, the energy management processor  506 ′ will estimate a storage parameter to ensure that the energy storage system  204 ′ has adequate secondary stored energy so that the locomotive can meet this anticipated traction and/or auxiliary energy demand. Additionally, the energy management processor  506 ′ may estimate a transfer parameter at a fixed location d 3  where an upcoming dynamic braking mode region is anticipated. For example, the energy management processor  506 ′ may anticipate an upcoming negative traction and/or auxiliary energy demand (ie. dynamic braking region, or energy storage system charging region), indicative of an upcoming charging region and thereby estimate a transfer parameter, so that the energy storage system efficiently transfers all of its stored energy prior to entering the charging region. 
   As the locomotive  100 ′ travels across the route, the energy management processor  506 ′ continuously compares the estimated storage parameter and transfer parameter with an actual storage parameter and actual transfer parameter at each incremental position  518 ′ along the route. In the event that the actual storage and transfer parameters and the estimated storage and transfer parameters differ by greater than a predetermined threshold at each of the incremental positions along the one of a plurality of routes, the energy management processor switches into a default mode such that a locomotive operator manually controls the storage and transfer of electrical energy to the energy storage system. Additionally, if the energy management processor  506 ′ determines that there is no historic data available for an upcoming route, and thus no anticipated traction and/or auxiliary energy demand may be constructed, the energy management processor similarly switches to a default mode. 
     FIG. 18  illustrates an exemplary energy management method  1200 ′ for use with one of a plurality of hybrid energy diesel electric locomotives  100 ′. Each locomotive  100 ′ has an  102 ′ engine and power converter  104 ′,  106 ′ providing primary electric power, and a traction bus  108 ′ coupled to the power converter to carry the primary electric power. A traction motor  108 ′ is connected to the traction bus, and has a motoring mode responsive to the primary electric power to propel the one of a plurality of locomotives  100 ′ on one of a plurality of routes. Additionally, the traction motor  108 ′ has a dynamic braking mode to generate dynamic braking electrical energy on the traction bus. The energy management method  1200 ′ begins (block  1201 ′) by storing (block  1202 ′) historical data of a traction and/or auxiliary energy demand for each locomotive  100 ′ at each incremental position along each route in a database. Additionally, the method includes retrieving (block  1204 ′) the historical data  512 ′,  514 ′,  516 ′ of each locomotive  100 ′ for each of the incremental positions  518 ′ along one of the plurality of routes. The method  1200 ′ further includes providing (block  1206 ′) position information of one of a plurality of locomotives  100 ′ at incremental positions  518 ′ along one of a plurality of routes. Additionally, the method includes estimating (block  1208 ′) an anticipated traction and/or auxiliary energy demand  520 ′ of one of a plurality of locomotives  100 ′ at each of the incremental positions  518 ′ along one of a plurality of routes, before ending at  1209 ′. 
   Based on the foregoing specification, the above-discussed embodiments of the invention may be implemented using computer programming or engineering techniques including computer software, firmware, hardware or any combination or subset thereof, wherein the technical effect is to provide an energy management system for use with one of a plurality of hybrid energy diesel electric locomotives. Any such resulting program, having computer-readable code means, may be embodied or provided within one or more computer-readable media, thereby making a computer program product, i.e., an article of manufacture, according to the discussed embodiments of the invention. The computer readable media may be, for instance, a fixed (hard) drive, diskette, optical disk, magnetic tape, semiconductor memory such as read-only memory (ROM), etc., or any transmitting/receiving medium such as the Internet or other communication network or link. The article of manufacture containing the computer code may be made and/or used by executing the code directly from one medium, by copying the code from one medium to another medium, or by transmitting the code over a network. 
   One skilled in the art of computer science will easily be able to combine the software created as described with appropriate general purpose or special purpose computer hardware, such as a microprocessor, to create a computer system or computer sub-system of the method embodiment of the invention. An apparatus for making, using or selling embodiments of the invention may be one or more processing systems including, but not limited to, a central processing unit (CPU), memory, storage devices, communication links and devices, servers, I/O devices, or any sub-components of one or more processing systems, including software, firmware, hardware or any combination or subset thereof, which embody those discussed embodiments the invention. 
   This written description uses examples to disclose embodiments of the invention, including the best mode, and also to enable any person skilled in the art to make and use the embodiments of the invention. The patentable scope of the embodiments of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.