Abstract:
A vehicle power system includes a plurality of power distribution divisions, a rechargeable energy storage system, switching devices for connection of the power distribution divisions to the rechargeable energy storage system, a plurality of loads energized from the power distribution divisions, a control network including nodes for control over the loads and the switching devices, a mobile transponder and a transceiver which is connected to the controller area network and which provides for communicating with the transponder. Sensors monitored by the controller area network and proximity of the mobile transponder determine a state for vehicle power distribution system.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The technical field relates generally to state control of electrical power distribution systems on motor vehicles, and more particularly, to a state control system for a high voltage power distribution system which anticipates operator operational demands based on driver location in the motor vehicle, driver movement proximate to the motor vehicle and location of the motor vehicle. 
         [0003]    2. Description of the Technical Field 
         [0004]    Electric and hybrid vehicles, particularly hybrid-electric vehicles, are increasingly common, particularly for buses and for commuter and urban delivery applications. The electrical power distribution systems for these vehicles usually include more than one high voltage electric power distribution sub-systems because, in part, high voltage power distribution reduces current losses. The power distribution sub-systems may operate at different nominal voltage levels and both direct current (DC) or alternating current (AC) sub-systems may be present. 
         [0005]    Power is supplied to the high voltage electric power distribution sub-systems from the vehicle&#39;s rechargeable energy storage system (RESS). For an electric vehicle the RESS is the exclusive source of power during vehicle operation. The RESS is usually a substantial battery system, though it may be constructed in alternative forms, such as capacitors or even fuel cells. Contemporary RESS units, particularly those constructed from batteries, tend to exhibit a relatively low density energy storage in comparison to fossil fuels, and as a consequence, the all electric range of electric and hybrid vehicles is usually substantially less than it is for vehicles which burn fossil fuels. 
         [0006]    Specialized switching devices such as contactors are used to control connection of the RESS to the high voltage electric power distribution sub-systems. Because closure of the contactors can produce a large current inrush to previously unenergized high voltage sub-systems, the power distribution system will often include a pre-charge resistor system. A plurality of contactors are provided which allow current to be routed through the pre-charge resistors to prevent an initial current surge from the RESS and to bypass the pre-charge resistors to reduce losses during operation. In this way initial power flow on power up is limited. The process of powering up can, however, take an appreciable amount of time to carry out. 
         [0007]    Contemporary vehicles use distributed computer control over vehicle systems. This includes control over electrical power distribution. Distributed control includes system specific controllers such as: transmission controllers, engine controllers and motor controllers associated with the drive train; ancillary controllers such as used for power steering motors and the like; and, battery management systems associated with the RESS. The controllers are linked by wiring or optical cable for the exchange of data. The linkage is commonly operated in what is termed a controller area network (CAN) with the controllers providing network nodes. The network nodes/controllers are computers and thus they consume power. They also take appreciable time to boot up and shut down. 
         [0008]    Keeping a power distribution system in a state of full readiness can be a substantial power drain on the RESS. Good energy management of the RESS calls for minimizing energy/power drains on the RESS to increase vehicle range. This in turn suggests that vehicle electric power distribution sub-systems could be powered down when not in use to avoid a drain on the RESS. The time taken to shut down and energize the power distribution sub-systems and to boot up on board computer are practical limitations on taking such steps, particularly on a vehicle used for small package delivery. 
       SUMMARY 
       [0009]    A vehicle electrical energy/power distribution system includes a plurality of distribution divisions, a rechargeable energy storage system, a plurality of switching devices for selective connection of distribution divisions to the rechargeable energy storage system, a plurality of loads connected for energization to the distribution divisions, a mobile transponder, a controller area network including a plurality of nodes with control nodes for control over the plurality of loads and the plurality of switching devices, a mobile transponder and a transceiver which is connected to the controller area network and which provides for communicating with the transponder. There is a controller area network node connected for communication with a plurality of vehicle sensors which in turn are responsive to operator location in the vehicle and vehicle status. The transponder and transceiver cooperate to establish transponder distance from the vehicle. Each of several possible electrical power distribution system states are triggered based on proximity of a transponder and status of the sensors. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is an illustration of a delivery vehicle. 
           [0011]      FIG. 2  is a high level schematic of the electrical system for a vehicle incorporating a rechargeable electrical storage system. 
           [0012]      FIG. 3  is a state machine. 
           [0013]      FIG. 4  is a map illustrating boundaries associated with particular states of the electrical power system of  FIG. 2 . 
           [0014]      FIG. 5  is a data flow definition of an in-vehicle mode. 
           [0015]      FIG. 6  is a data flow definition of a vehicle proximity mode. 
           [0016]      FIG. 7  is a data flow definition of an inside delivery boundary mode. 
           [0017]      FIG. 8  is a data flow definition of an outside delivery boundary mode. 
           [0018]      FIG. 9  is a flow chart for a simple proximity architecture. 
           [0019]      FIG. 10  is a flow chart for an architecture combining other sensor inputs with a proximity architecture. 
           [0020]      FIG. 10B  is a flow chart for an external proximity sensor. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    In the following detailed description, like reference numerals and characters may be used to designate identical, corresponding, or similar components in differing drawing figures. Furthermore, example sizes/models/values/ranges may be given with respect to specific embodiments but are not to be considered generally limiting. 
         [0022]    Referring now to the drawings and in particular  FIG. 1 , a delivery vehicle  10  is illustrated. Delivery vehicle  10  is illustrated as a van type vehicle though other types of vehicles adapted for delivery purposes and indeed the teachings of this disclosure may be applied to a variety of types of vehicles including tractor and trailer combinations, buses and automobiles. 
         [0023]    Delivery vehicle  10  is driven by an operator from an operator station  12  located facing an instrument and control panel  15 . A sensor may associated with the operator station  12  to indicate whether the operator station is occupied. Vehicle  10  is equipped with a door  17  by which the authorized operator may enter and depart the vehicle. A sensor switch may be used in conjunction with door  17  to indicate whether the door is open or closed. A cargo area  16  may be accessed from the front operator station  12  via a sliding door  18  or a rear tailgate  20 . The cargo area may be illuminated by a skylight (not shown) in the roof and/or a work lamp  24  located in the cargo area  16 . Lights  22  are shown illustrated at the rear of vehicle  10 . 
         [0024]    The driver of delivery vehicle  10  will come and go from the vehicle from time to time for various purposes, such as to complete a delivery, make a pick up, or when the vehicle is parked at location for loading or when out of immediate service. Delivery vehicle  10  incorporates a drive train which is based, at least in part, on electric motors for propulsion. An electrical system with high voltage power distribution potential is provided for powering the electrical motors. The electrical system of delivery vehicle  10  can be programmed to assume states which conserve power in response to various of these situations. State transitions are triggered in response to operator actions and movement and in response to vehicle location so that transitions between states are initiated, and may be completed, prior to driver operational demands on the vehicle or upon conclusion of operator operation demands. 
         [0025]      FIG. 2  is a high level schematic of a vehicle electrical system representative of one environment in which the teachings of the present disclosure may be applied. The vehicle electrical system is elaborated upon in the context of a drive train  71 . The vehicle could be an all electric vehicle or provide alternative on-board mechanisms for recharging the vehicle RESS than an IC engine  48 . Drive train  71  is illustrating incorporating a motor  81  for propulsion and the vehicle includes the RESS (here batteries boxes  38 ,  39 ) which can be used as a source of power for motor  81 . Where drive train  71  is hybridized, a non-electric power source  48 , such as an internal combustion (IC) engine, a gas turbine, a Stirling engine, or other power source, may be added as an option to drive a generator  73  and thereby support propulsion or to provide direct propulsion. A fuel cell may replace the combination of non-electric power source and generator, or where it is regenerative may serve as an RESS. Generator  73  provides one mechanism for recharging the vehicle RESS  38 ,  39 . For vehicles where the RESS serves as a source of electrical power the hybrid traction motor  81  could be replaced with an electrical machine to provide regenerative braking and for recharging the vehicle RESS  38 ,  39 . 
         [0026]    In the system of  FIG. 2  a high voltage distribution box  37  provides direct electrical connections from a vehicle RESS  38 ,  39  to each of three high voltage direct current (DC) power distribution sub-systems. The high voltage DC power distribution sub-systems operate at two distinct DC voltage levels. There is a 350 volt DC level supported by first and second ancillary systems buses  13  and  19 . There is also a 700 volt DC feed line  21 . A low voltage sub-system  65  is supported from the ancillary systems buses  13  and  19 . A high voltage inverter/converter  46  provides an interface between the high voltage DC current feed line  21  and a three phase the alternating current (AC) sub-system associated with optional generator  73  and motor  81 . 
         [0027]    Control over power distribution is implemented using network data link  25  which provides data communication between the nodes of the network comprising ancillary controllers  34  and  35 , an electronic system controller (ESC)  40  and slave elements of the ESC  40  such as a remote power module (RPM)  26 , and controllers (not shown) for the vehicle drive train which may be drive train  71 . Taken together these data links and nodes may be operated to implement controller area networks (CAN). 
         [0028]    High voltage DC power distribution comes out of a high voltage distribution box  37 . High voltage distribution box  37  houses first and second DC ancillary buses  13  and  19  and is the source of the 700 volt DC feed line  21 . RESS  38 ,  39 , include traction batteries  42 ,  43  which are electrically connected to first and second high voltage DC buses  13  and  19 . Each of the traction batteries  42 ,  43  support a nominal potential of 350 volts. The negative and positive terminals of traction battery  42  are electrically connected to the two wires of bus  13 , respectively, and the negative and positive terminals of traction battery. The positive terminal of traction battery  42  is electrically connected to the negative terminal of traction battery  43  to build a 700 volt in-series power source for DC feed line  21 . The negative terminal of traction battery  42  is connected to one of connectors  67  through with it may be electrically connected to the converter/inverter  46 . The positive terminal of high voltage traction battery  43  is connected to a pre-charge resistor block  64  and from there to one of connectors  67  for electrical connection to the inverter/converter  46 . The electrical connection between the 700 volt DC feed  21  and the traction motor  81  is through the high voltage inverter/converter  46  which operates at 700 volts DC from a 700 volt direct current feed  21  side and at a high voltage, variable frequency, three phase alternating current on the traction motor side. 
         [0029]    Whether current flows through the resistors of the pre-charge resistor block  64  depends upon the closed/open states of three contactors  67 . Contactors&#39;  67  states change more than once for a transition from a deenergized state to an energized state, first to interpose the resistor block  64  to limit current discharge from traction batteries  42  and  43  and later, during operation, to remove the resistor block from the circuit and reduce power loss. Contactors&#39;  67  states are controlled by a high voltage distribution box controller  83  which communicates with ESC  40  over data link  25 . Ultimately operation of the high voltage distribution box controller is controlled by instructions from the ESC  40 . 
         [0030]    High voltage distribution box controller  83  also controls the closed/open states of a plurality of ancillary systems contactors  34 ,  35  associated with ancillary systems buses  13 ,  19 , respectively. The ancillary systems include diverse electrical loads including high voltage DC motors  32 ,  57 ,  59  and  85  which may be used to support power steering, air conditioning compressors, air pumps and the like and auxiliary system DC-DC converters  62 A,  62 B which supply DC power to an auxiliary power system  65 . Contactors  34 ,  35  may, as allowed by the specific application, be open during a transition to limit current inflow. 
         [0031]    Auxiliary DC power system  65  may represent a number of different system, such the electrical power distribution system for a trailer or low voltage components of vehicle such as delivery vehicle  10  where it could be the immediate, filtered power source for on-board electronics such as the nodes of the vehicle CAN network. A representative auxiliary DC power system  65  is represented here has comprising two storage batteries  60 ,  61 . The power system  65  may be energized without closure of its associated ancillary systems contactors. When the contactors are closed the chassis batteries  60 ,  61  function as filters to stabilize low voltage system voltage. The low voltage power sub-system  65  supplies logic operating power to the nodes of the control system including ESC  40 , ancillary motor controllers  31 ,  56 ,  58  and  84 , RPM  26  and to the high voltage distribution box controller  83 . 
         [0032]    RESS  38  and  39  include battery management system (BMS) controllers  70  which report over hybrid CAN data link  25  on traction battery voltage and current flow into and out of the sub-packs. 
         [0033]    The electrical power distribution system has a plurality of states related to which portions of the system are active or “hot” and which components can draw power. The power distribution system is a multi-division system which can be used with hybrid electric drive train  71  and to supply power to high voltage DC to ancillary loads such motors  32 ,  57 ,  59  and  85  and to DC/DC converters  62 A-B. 
         [0034]    Among the nodes coupled to the low voltage sub-system to support operation of its logic is RPM  26 . RPM  26  is connected to at least two internal vehicle sensors used to indicate the location of a driver with respect to or in the vehicle. One sensor is a seat sensor  49  located proximate to or in the driver&#39;s station seat of the vehicle. Seat sensor  49  indicates whether the seat is occupied (or at least is supporting a load consistent with the seat being occupied). The second sensor is a door sensor  51  which indicates whether the door most likely used by a driver is opened or closed. 
         [0035]    RPM  26  also communicates with a transponder such as a transponder  75  such as a long range radio identification (RFID) tag or other wireless device using a transceiver interrogator  47 . The transponder  75  is uniquely identified and which may be assigned to an authorized operator of the vehicle. Distance between the transceiver  47  and the transponder  75  may be determined by the time delay between responses to periodic interrogation signals generated by the transceiver  47 . transponder  75  may be either a passive (powered by the interrogation signal) or active (internal battery powered) device. Alternatives to using an RFID tag include optical devices such as infrared and ultraviolet transceivers. 
         [0036]    The transceiver/interrogator  47  can be installed on vehicle  10  and permanently integrated into the vehicle  10  as shown. Alternatively a transceiver/interrogator  47  can be external, and permanently mounted at a location such as a loading dock. Two way communications between the transceiver/interrogator  47  and a two way communication device installed on the vehicle or the transceiver/interrogator  47  may be plugged into a vehicle which has docked at the loading dock. In this way the vehicle proximity boundary and the within delivery area boundary can be located and even shaped to a specific zone which may or may not include the vehicle. Determination of a state/mode for the vehicle can be executed externally to the vehicle and transmitted to the vehicle, or the vehicle can be programmed to operate on the inputs. 
         [0037]    A state or mode of a system may be considered to be a condition of existence that a system or component of a system may be in.  FIG. 3  illustrates four states/modes of the electrical power distribution system which the system may assume in response to driver position, RFID tag location and sensor status. For convenience sake these states/modes are tagged here by reference to presumed driver location, changes in which drive transitions between the states. The four states/modes are identified in that sense as: 1) In vehicle mode/state  72 ; 2) Vehicle proximity mode  74 ; 3) Inside delivery boundary mode  76 ; and, 4) Outside delivery boundary mode  78 . State/mode transitions occur only with immediately adjacent modes, that is transitions can occur between modes  72  and  74 , between modes  74  and  76 , and between modes  76  and  78 . 
         [0038]      FIG. 4  graphically illustrates a defined area having a relationship to delivery vehicle  10 , in this case boundary conditions centered on the vehicle relating to location of the transponder  75  relative to the vehicle. The boundary conditions define zones with the defined area with the zones corresponding one to one to the states/modes  72 ,  74 ,  76  and  78  assumed by the vehicle. A delivery boundary  79  may be defined based on the maximum expected distance that an authorized RFID tag carrier  88  such as a driver will travel from the delivery vehicle  10  (or more precisely transceiver  47 ) in making his/her rounds. The delivery boundary  79  divides when the “Outside Delivery Boundary” mode  78  is assumed by vehicle  10  from when the “Inside Delivery Area” mode  76  is assumed. Similarly a vehicle proximity boundary  75  divides the “Inside Delivery Boundary” mode  76  from the “Vehicle Proximity” mode  74 . Division of the “In-Vehicle” mode  72  from the “Vehicle Proximity” mode  74  is not a strictly driven by distance between the on vehicle transceiver  47 , but depends upon status changes in seat sensor  49  and door sensor  51 . It should be understood that the boundaries may change as a function of vehicle  10  and service conditions. 
         [0039]      FIGS. 5-8  provide a graphical representation of the definition of the four states/modes  72 ,  74 ,  76  and  78 . The states/modes are assumed by the electrical power distribution system of delivery vehicle  10  in response to changing sensor inputs and distance to transponder  75  measurements. 
         [0040]    The In-Vehicle Mode  72  ( FIG. 5 ) provides that the high voltage power distribution sub-system  21  is energized (contactors  67  are closed), the drive train  71  is enabled and the contactors for all high voltage ancillary systems  100  are allowed to be closed. The door sensors  51  indicate all doors are closed and the occupant sensor  49  indicates that the occupant sensor in on. Transceiver  47  will provide distance measurements to the transponder  75  that indicate that the tag is close to the vehicle. The output of the sensors  49 ,  51  is passed by the slave controller (RPM  26 ) to the master controller (ESC  40 ). A run command  89 , indicating that the vehicle control is system is to be kept fully enabled, is applied to the master controller/ESC  40 . The continued presence of this command relating to all states/modes described indicates that the system is to be kept in a position to respond to changes in the outputs of the sensors  49 ,  51  and the transceiver  47 . 
         [0041]    In the Vehicle Proximity Mode  74  ( FIG. 6 ) the high voltage power distribution sub-system  21  is energized, the drive train  71  is disabled (standby) and the contactors for all high voltage ancillary systems  100  are allowed to close. The door sensors  51  indicate at least one door is open and the occupant sensor  49  indicates that the occupant sensor is off. Transceiver  47  will provide distance measurements to the transponder  75  that indicate that the tag is close to the vehicle. The output of the sensors  49 ,  51  is passed by the slave controller (RPM  26 ) to the master controller (ESC  40 ). 
         [0042]    In the Inside Delivery Boundary Mode  76  ( FIG. 7 ) the high voltage power distribution sub-system  21  is energized, the drive train  71  is disabled and high voltage ancillary systems  100  are placed on standby. The door sensors  51  indicate at least one door is open and the occupant sensor  49  indicates that the occupant sensor is off Transceiver  47  will provide distance measurements to the transponder  75  that indicate that the tag is outside the vehicle proximity boundary but inside the outside delivery area boundary. 
         [0043]    In the Outside Delivery Boundary Mode  78  ( FIG. 8 ) the high voltage power distribution sub-system  21  is cut off by opening of the RESS contactors  67 , the drive train  71  and high voltage ancillary systems  100  are disabled. The door sensors  51  indicate at least one door is open and the occupant sensor  49  indicates that the occupant sensor is off. Transceiver  47  will provide distance measurements to the transponder  75  that indicate that the tag is outside the delivery area boundary. 
         [0044]      FIG. 9  is a flow chart reflecting operation of proximity detection of the transponder  75  to be carried by an operator/authorized carrier  88  and its ordered relation to establishing an electrical power distribution system state taking into account a plurality of vehicle calibratable parameters. RFID tags  75  generate response signals to an interrogation signal which upon reception ( 101 ) allow for a calculation  102  to determine distance to the tag to occur. The relation of distance to mode conditions is itself programmed. To this end a number of vehicle calibratable parameters  106  may be considered. The parameters that may be used may include transponder  75  RF frequency, the boot time for unenergized control system nodes on the vehicle, which enabled nodes are available, the configuration of the battery pack and its relation to the time taken to charge the power distribution system, the time taken to charge a particular drive train configuration, and the choice of vehicle system enabled through active CAN massages. The vehicle calibration library  106  provides inputs to a set vehicle modes step  104 . Modes/states  72 ,  74 ,  76  and  78  a representative of modes that may be provided. Active vehicle CAN messages  108  are considered at step  110  against the available modes set at step  104  to enable a vehicle mode. Appropriate responsive CAN messages  112  are then generated to establish and maintain the mode. 
         [0045]      FIG. 10  is an alternative flow chart relating to establishing states/modes in response to operator location relative to a vehicle and expanded to take into consideration his/her actions. Here operator zone locating functionality is combined with consideration of the other sensors, such as the occupant sensor. A signal processing step  103  is substituted for step  101  of  FIG. 9 . Step  103  takes into account an input  120  from the driver seat occupant sensor  49 , and transponder  75  response signals from either or both of an in-cab transceiver  116  or an transceiver utilizing an outside antenna  118 . Signal processing  103  is used to determine driver location inside or outside the vehicle and to provide data to a distance determination step  102 . Distance than is input to a set vehicle mode conditions step  104 , which also operations on values from the vehicle calibration library  106 . The output of step  104  is provided step  110  to enable the vehicle set by step  104 . This includes output signals to enable the high voltage distribution system  114 , messages over the CAN network (step  112 ) and receipt of active vehicle CAN messages (step  108 ). 
         [0046]      FIG. 10B  reflects modifications to the process specifically for a loading zone transceiver which may or may not be installed on the vehicle  10 . Here a vehicle loading zone transceiver signal  122  provides the input to the set mode for operational phase of the drive cycle step  124 . Once a state/mode is set messages are broadcast (step  126 ) for pick up by a vehicle exterior sensor (not shown). The defined area, while still related to vehicle position, may not include the actual location of the vehicle.