Abstract:
A hybrid battery system of an automotive vehicle provides power to various features without running an internal combustion engine.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to systems and methods for powering power consuming vehicle accessories during an off state of the vehicle. 
         [0003]    2. Discussion 
         [0004]    Prior to use, a vehicle may have an interior climate that is not preferred by a user. For example, the vehicle may be colder, e.g., cold soaked, or warmer, e.g., hot soaked, than desired. An internal combustion engine may be used to power climate control features to achieve a desired interior climate. 
       SUMMARY 
       [0005]    Embodiments of the invention may take the form of a system for powering a power consuming vehicle accessory. The system includes a power plant, a traction battery, and an electric motor to operatively couple the power plant and traction battery. The system also includes a traction battery controller connected with the traction battery to periodically monitor a state of charge of the traction battery and to enable the traction battery to power the power consuming vehicle accessory. 
         [0006]    Embodiments of the invention may take the form of a method for powering a power consuming vehicle accessory. The method includes receiving a command signal to enable the traction battery to power the power consuming vehicle accessory, determining whether a current state of charge of the traction battery is greater than a predetermined state of charge, and enabling the traction battery to power the power consuming vehicle accessory. 
         [0007]    While exemplary embodiments in accordance with the invention are illustrated and disclosed, such disclosure should not be construed to limit the claims. It is anticipated that various modifications and alternative designs may be made without departing from the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a block diagram of a power system for features of a hybrid electric vehicle and shows a high voltage traction battery capable of being selectively electrically connected with an electric motor, a DC/DC power converter, and/or an electric heater via a set of switches. 
           [0009]      FIG. 2A  is a block diagram of a portion of the power system of  FIG. 1  and shows the switches configured such that the high voltage traction battery is electrically connected with the motor/generator. 
           [0010]      FIG. 2B  is another block diagram of a portion of the power system of  FIG. 1  and shows the switches configured such that the high voltage traction battery is electrically connected with the DC/DC power converter. 
           [0011]      FIG. 2C  is still another block diagram of a portion of the power system of  FIG. 1  and shows the switches configured such that the high voltage traction battery is electrically connected with the electric heater. 
           [0012]      FIG. 3  is a flow chart of a method for powering a feature during a vehicle off state in accordance with an embodiment of the invention. 
           [0013]      FIG. 4  is a flow chart of a control strategy employed by a high voltage battery controller in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Powering climate control features with a power plant, such as an internal combustion engine, may increase fuel consumption, emissions, and efficiency losses. Embodiments of the invention may use a battery system to provide power to various climate control features thereby minimizing fuel consumption, emissions, and efficiency losses. 
         [0015]    Embodiments of the invention may use traction battery power for functions beyond vehicle propulsion. For example, seats may be cooled by activating an air conditioning system&#39;s compressor and fan. A DC/DC power converter may be powered with the traction battery to run a 12V accessory circuit to power an air pump. The air pump may be used to inflate various items including floats for swimming or an air mattress for camping. Flat tires may be inflated on site with the device as well. 
         [0016]    Embodiments of the invention may power a DC/DC power converter with a traction battery to run an inverter supplying an external 110V outlet. The external outlet may be used for various functions including powering a television, mini-refrigerator, external radio, external CD player, or other tailgating accessories. Any other equipment requiring a 110V outlet could also be powered. 
         [0017]    Embodiments of the invention may power a DC/DC power converter with a traction battery to support a 12V system for extended use. A vehicle may automatically institute auxiliary power for in vehicle accessories or a customer may choose to initiate auxiliary power for in vehicle accessories via an input into a battery controller. Extended use of 12V accessories may allow the customer to use an audio/video system for an extended period of time. It may also allow a customer to use headlights or hazard lights for an extended period of time. 
         [0018]      FIG. 1  is a block diagram of power system  10  of vehicle  12 . Vehicle  12  has an on state, e.g., key on, and an off state, e.g., key off. Power system  10  includes high voltage traction battery  14 . High voltage traction battery  14  includes battery cells  16 , e.g., Nickel Metal Hydride (NiMH), Lithium Ion, battery controller  18 , and switches  20 ,  22 ,  24 ,  26 ,  28 . As explained below, high voltage traction battery  14  may be selectively electrically connected with motor/generator  30 . High voltage traction battery  14  may also be selectively electrically connected with DC/DC power converter  34  and electric heater  36 . 
         [0019]    DC/DC power converter  34  is electrically connected with air conditioning compressor  38  and heated seat/heated steering wheel  40 . In alternative embodiments, DC/DC power converter may be electrically connected with any number/type of loads, e.g., electric window defroster. Motor/generator  30  is coupled with power plant  32 , e.g., engine, fuel cell. Engine  32  is configured, in typical fashion, to move vehicle  12  via a drivetrain. 
         [0020]    Battery controller  18  controls switches  20 ,  22 ,  24 ,  26 ,  28 , e.g., field effect transistors, contacts, etc. As such, high voltage traction battery  14  may be selectively electrically connected with motor/generator  30 , electric heater  36 , air conditioning blower  38  (via DC/DC power converter  34 ), and heated seat/heated steering wheel  40  (again, via DC/DC power converter  34 ). As shown in  FIG. 1 , switches  20 ,  22 ,  24 ,  26 ,  28  are open and thus high voltage traction battery  14  is not electrically connected with motor/generator  30 , electric heater  36 , air conditioning blower  38 , or heated seat/heated steering wheel  40 . 
         [0021]      FIG. 2A  is a block diagram of high voltage traction battery  14 . If battery controller  18  is to electrically connect battery cells  16  and motor/generator  30 , battery controller  18  closes switches  20 ,  22 ,  24 ,  26  by activating, for example, a solenoid internal to switches  20 ,  22 ,  24 ,  26 . 
         [0022]      FIG. 2B  is another block diagram of high voltage traction battery  14 . If battery controller  18  is to electrically connect battery cells  16  with air conditioning blower  38  and/or heated seat/heated steering wheel  40 , battery controller  18  closes switches  20 ,  22 ,  26 . 
         [0023]      FIG. 2C  is still another block diagram of high voltage traction battery  14 . If battery controller  18  is to electrically connect battery cells  16  with electric heater  36 , battery controller  18  closes switches  20 ,  22 ,  28 . 
         [0024]    As described above, because high voltage traction battery  14  may be electrically connected with electric heater  36 , air conditioning blower  38 , and/or heated seat/heated steering wheel  40  while not being electrically connected with motor/generator  30 , high voltage traction battery  14  may be electrically connected with electric heater  36 , air conditioning blower  38 , and/or heated seat/heated steering wheel  40  while vehicle  12  is in its off state, e.g., key off. 
         [0025]    High voltage traction battery  14  is used to start engine  32  via motor/generator  30  by supplying high voltage power to motor/generator  30 . As such, battery controller  18  determines whether battery cells  16  have sufficient state of charge, e.g., 20% for a NiMH battery at 25° C., to start engine  32  prior to, and while, providing any power to, for example, electric heater  36  and/or DC/DC power converter  34  if vehicle  12  is in its off state. Battery controller  18  thus periodically monitors the state of charge of battery cells  16 . For example, every 20 minutes, the threshold state of charge necessary to start engine  32  is reevaluated based on the temperature and stand time of high voltage traction battery  14 . As temperature decreases and/or stand time increases, the threshold state of charge may increase. Likewise, as temperature increases and/or stand time decreases, the threshold state of charge may decrease. Testing, at various temperatures and stand times, may be conducted to determine such threshold states of charge for a particular application. This ensures that the state of charge of battery cells  16  does not drop to a level such that engine  32  cannot be started. In alternative embodiments, battery controller  18  may continuously monitor the state of charge of battery cells  16 . 
         [0026]    If the state of charge of high voltage traction battery  14  drops below that which is necessary to start engine  32 , battery controller  18  may disconnect battery cells  16  by removing, for example, power to solenoids associated with any of switches  20 ,  22 ,  26 ,  28  that are closed so as to preserve the power necessary to start engine  32 . 
         [0027]    Vehicle  12  includes input interface  42 , e.g., buttons, dials, etc., which permit a user to select/activate vehicle climate control functions, e.g., air conditioning compressor, heating, even if engine  32  is off, e.g., vehicle  12  is in its off state. Battery controller responds to commands input via input interface  42  and operates switches  20 ,  22 ,  24 ,  26 ,  28  as described above to effectuate the desired climate control. Battery controller  18  also permits a user, via input interface  42 , to preset, e.g., user selected, certain vehicle climate control functions such that they are activated after a designated period of time, e.g., seven hours. For example, battery controller  18  starts a real time clock feature and will count to the specified time. Once the specified time is reached, the function is enabled. The climate of vehicle  12  may thus be more favorable when the user later enters vehicle  12  for use. 
         [0028]    Device  44 , e.g., key fob, etc., may be used to transmit command signals to battery controller  18  for vehicle climate control functions if engine  32  is off, e.g., vehicle  12  is in its off state. The user of device  44  may issue a command signal by, for example, pressing a button which in turn prompts battery controller  18  to selectively close at least one of switches  20 ,  22 ,  26 ,  28  so that during the off state of vehicle  12  at least one of electric heater  36 , air conditioning blower  38 , and heated seat/heated steering wheel  40  are operable. 
         [0029]      FIG. 3  is a flow chart of a method for powering a feature during a vehicle off state. At step  50 , a signal to enable high voltage traction battery  14  to power electric heater  36  is generated. At  52 , the signal to enable high voltage traction battery  14  to power electric heater  36  is received. At  54 , the state of charge of high voltage traction battery  14  is monitored. At  56 , switches  20 ,  22 ,  28  are closed if the state of charge of high voltage traction battery  14  is greater than a predetermined state of charge. At  58 , at least one of switches  20 ,  22 ,  28  is opened if the state of charge of high voltage traction battery  14  is less than the predetermined state of charge. 
         [0030]      FIG. 4  is a flow chart of control strategy for a high voltage battery controller to provide power to one or more vehicle features. At  62 , the controller receives a command to provide power to a vehicle feature. At  64 , the controller determines whether the state of charge of a high voltage battery is sufficient to start an engine. If no, the controller does nothing. At  68 , if yes, the controller generates a control signal to close the appropriate switches to enable the high voltage battery to power the one or more vehicle features. At  70 , the controller determines whether the state of charge of the high voltage battery is sufficient to start the engine. At  72 , if no, the controller generates a control signal to open the switches closed at  68 . At  74 , if yes, the controller loops back to  70 . 
         [0031]    While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.