Abstract:
The present invention relates to a method and an apparatus for hybrid vehicle auxiliary battery state of charge control. In one embodiment, the present invention is an automobile including an electronic accessory, a first battery connected to the electronic accessory, and a control unit connected to the first battery, the control unit monitoring the first battery and disconnecting the first battery from the electronic accessory when the first battery is in a first operational condition.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The present invention relates to a method and an apparatus for hybrid vehicle auxiliary battery state of charge control. 
         [0003]    2. Background 
         [0004]    In an automobile, a user can often activate and use accessories in the automobile such as a radio or a light, even when the engine is not activated. This can drain a battery of the automobile such that the user is unable to start the engine of the automobile. 
         [0005]    Thus, there is a need for a method and apparatus to reduce the likelihood of the battery being drained such that the user is unable to start the engine of the automobile. 
       SUMMARY 
       [0006]    In one embodiment, the present invention is an automobile including an electronic accessory, a first battery connected to the electronic accessory, and a control unit connected to the first battery, the control unit monitoring the first battery and disconnecting the first battery from the electronic accessory when the first battery is in a first operational condition. 
         [0007]    In another embodiment, the present invention is an automobile including an electronic accessory, a first battery connected to the electronic accessory, an engine configured to be in an active or inactive state, a control unit connected to the first battery and the engine, the control unit monitoring the first battery, disconnecting the first battery from the electronic accessory when the first battery is in a first operational condition, and providing a warning to a user when the first battery is in a second operational condition. 
         [0008]    In yet another embodiment, the present invention is a method for controlling state of charge in an auxiliary battery in an automobile including the steps of monitoring an operation condition of the auxiliary battery, and disconnecting the auxiliary battery from electronic accessories when the auxiliary battery is in a first operation condition. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The features, objects, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, wherein: 
           [0010]      FIG. 1  is a schematic diagram of an embodiment of the present invention; and 
           [0011]      FIG. 2  is a flow chart of an embodiment of the present invention in operation. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Apparatus, systems and methods that implement the embodiments of the various features of the present invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate some embodiments of the present invention and not to limit the scope of the present invention. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements. 
         [0013]      FIG. 1  is a schematic diagram of an embodiment of the present invention. As seen in  FIG. 1 , an automobile  2  can include an engine  4 , a starter  6 , a main battery  8 , a control unit  10 , an auxiliary battery  12 , accessories  14 , a key reception unit  16 , and a warning unit  20 . 
         [0014]    As depicted in  FIG. 1 , automobile  2  is a hybrid car. Although automobile  2  is a hybrid car, automobile  2  can be, for example, any suitable car for transportation such as a car with a conventional internal combustion engine, and/or a car with a hydrogen engine. 
         [0015]    Engine  4  can be an internal combustion engine suitable for use in a hybrid car. Engine  4  can also be an electric engine or an engine to process hydrogen, ethanol, or other types of fuel. Engine  4  is connected to starter  6 , auxiliary battery  12 , and main battery  8  through a switch  22 . Engine  4  can be in an active state or inactive state. In an inactive state, engine  4  is off and is not running while in an active state, engine  4  is on and is running. 
         [0016]    Starter  6  is connected to engine  4 . It is also connected to main battery  8  through switch  22  which can be either engaged or disengaged. Starter  6  can start engine  4  through electricity supplied by main battery  8  when switch  22  is engaged. Starter  6  can include, for example, spark plugs. 
         [0017]    Main battery  8  is connected to control unit  10 , engine  4  and starter  6  through switch  22 , and auxiliary battery  12  through switch  24 . Main battery  8  can be, for example, a high voltage battery. Main battery  8  can supply electricity to engine  4  and/or starter  6  when switch  22  is engaged. Furthermore, when engine  4  is active and switch  22  is engaged, main battery  8  can provide power to aid engine  4  in moving automobile  2 . Also when switch  22  is disengaged, electricity from main battery  8  does not flow to engine  4  and/or starter  6 . Advantageously this can improve the safety of automobile  2  by preventing accidental discharges to engine  4  and/or starter  6  since main battery  8  can be a high voltage battery. With regards to switch  24 , when switch  24  is engaged, main battery  8  can supply electricity to auxiliary battery  12 . When switch  24  is disengaged, electricity does not flow from main battery  8  to auxiliary battery  12 . 
         [0018]    Auxiliary battery  12  is connected to engine  4 , accessories  14 , control unit  10 , and switch  22 . Auxiliary battery  12  is also optionally connected to main battery  8 . Auxiliary battery  12  can be a battery with a smaller energy storage capacity than main battery  8 . Advantageously this could reduce the weight of automobile  2  which can be particularly useful when automobile  2  is a hybrid car. In one embodiment, auxiliary battery  12  is a 12 volt battery. Auxiliary battery  12  may be connected to main battery  24  through switch  24  and accessories  14  through switch  26 . Switch  24  and switch  26  can be configured to be engaged or disengaged. As noted, when switch  24  is engaged, electricity can flow from main battery  8  to auxiliary battery  12 . When switch  24  is disengaged, electricity may not flow from main battery  8  to auxiliary battery  12 . Advantageously this can improve the safety of automobile  2  since main battery  8  can be a high voltage battery. 
         [0019]    When switch  26  is engaged, auxiliary battery  12  can supply electricity to accessories  14 . When switch  26  is disengaged, electricity can be prevented from flowing to accessories  14 . Advantageously, this can reduce the amount of electricity used by accessories  14  and prevent auxiliary battery  12  from being depleted or drained, such as when engine  4  is inactive or off. When engine  4  is active, engine  4  can recharge and replenish auxiliary battery  12 . Furthermore, auxiliary battery  12  can also control switch  22  by supplying electricity to engage or disengage switch  22 . As previously noted, the engagement of switch  22  allows main battery  8  to supply power to start engine  4  using starter  6 . 
         [0020]    Key reception unit  16  is connected to control unit  10  and can accept a key  18  which can engage key reception unit  16 . Key  18  can engage key reception unit  16  either physically, such as when key  18  is physically placed inside key reception unit  16 , or wirelessly, such as when key  18  transmits a signal to key reception unit  16  and/or key  18  establishes communication with key reception unit  16 . Key  18  can engage key reception unit  16  in two or more states such as an ACCESSORIES ON state or an ENGINE ON state. 
         [0021]    In the ACCESSORIES ON state, accessories  14  can be activated. It is also contemplated that some accessories  14  can be activated without key  18  being engaged with key reception unit  16 , or without key  18  being engaged with key reception unit  16  in the ACCESSORIES ON state. In such a case, the remaining accessories can be engaged when key  18  is engaged with key reception unit  16  in the ACCESSORIES ON state. During the ACCESSORIES ON state, engine  4  is inactive. The ACCESSORIES ON state can also be referred to as the READY OFF state. 
         [0022]    In the ENGINE ON state, engine  4  is activated. Furthermore, during the ENGINE ON state, auxiliary battery  12  can supply electricity to accessories  14  and engine  4  can recharge auxiliary battery  12 . The ENGINE ON state can also be known as the READY ON state. 
         [0023]    Warning unit  20  is connected to control unit  16  and/or auxiliary battery  12 . Warning unit  12  can be, for example, an audio emission device, a video display, and/or a combination of the audio emission device and the video display. Thus, warning unit  12  can provide a warning to a user such as an audio warning, visual warning, or and audiovisual warning to the user. 
         [0024]    Accessories  14  are connected to auxiliary battery  12  through switch  26 . Accessories  14  can be radios, lights, video players, etc. Accessories  14  can draw power from auxiliary battery  12  when switch  26  is engaged. If switch  26  is disengaged, accessories  14  is effectively disconnected from auxiliary battery  12  and power from auxiliary battery  12  to accessories  14  is cut off. 
         [0025]    Control unit  10  is connected to main battery  8 , auxiliary battery  12 , switch  24 , switch  26 , key reception unit  16 , and warning unit  20 . Control unit  10  can be an engine control unit, a microprocessor, an on-board diagnostics system, a computer chip, and/or any other device that can control or monitor the functions and/or components of automobile  2 . Control unit  10  can thus monitor auxiliary battery  12  and determine the voltage, power, and/or current level of auxiliary battery  12 . Furthermore, control unit  10  can also instruct auxiliary battery  12  to supply power switch  12  to engage or disengage switch  22 . Control unit  10  is also connected to key reception unit  16  and receives a signal from key reception unit  16  regarding the engagement of key  18  to key reception unit  16 . Based on the signal, control unit  16  can also control switch  24  and switch  26  to engage or disengage appropriately. Control unit  10  can also determine whether key  18  is engaged with key reception unit  16  in an ENGINE ON state or ACCESSORIES ON state. 
         [0026]    Control unit  10  also controls warning unit  20  to display or sound an alarm at appropriate times. By selectively controlling switch  26  and warning unit  20 , control unit  10  can warn a user when accessories  14  should be turned off and also when auxiliary battery  12  will be disconnected from accessories  14 . Control unit  10  can also warn a user to activate engine  4  so that auxiliary battery  4  can be replenished. By disconnecting auxiliary battery  12  from accessories  14 , the present invention can advantageously preserve a sufficient state of charge within auxiliary battery  12  to engage switch  22  when a user wishes to drive automobile  2 . Otherwise, if auxiliary battery  12  is drained, then auxiliary battery  12  may not have a sufficient state of charge to engage switch  22  to allow main battery  8  to start engine  4  using starter  6 . 
         [0027]      FIG. 2  is a flow chart of an embodiment of the present invention in operation. As seen in  FIG. 2 , the process begins in step S 200 . In step S 212 , control unit  10  determines whether engine  4  is active or not. Engine  4  can be active, for example, when key  18  is engaged with key reception unit  16  in an ENGINE ON state. Engine  4  is inactive when key  18  is disengaged from key reception unit  16  and/or key  18  is engaged with key reception unit  16  in an ACCESSORIES ON state but not in an ENGINE ON state. If engine  4  is active, then the process ends in step S 222 . 
         [0028]    Otherwise, if engine  4  is inactive, the process continues in step S 214 . In step S 214 , control unit  4  determines whether auxiliary battery  12  is operating in a warning condition. For example, auxiliary battery  12  can be operating in a warning condition when the engine is inactive and when a voltage of auxiliary battery  12  falls below a first predetermined voltage threshold, a power of auxiliary battery  12  falls below a first predetermined power threshold, and/or a current of auxiliary battery  12  falls below a first predetermined current threshold. For example, if the first predetermined threshold for auxiliary battery  12  is 6 volts and the voltage of auxiliary battery  12  is 5 volts, then auxiliary battery  12  is operating in a warning condition. Furthermore, auxiliary battery  12  could be operating in a warning condition when the engine is inactive when a first predetermined amount of time has expired from a triggering event, such as when accessories  14  is activated. For example, if the first predetermined amount of time is 30 minutes and more than 30 minutes has elapsed since accessories  14  was activated, then auxiliary battery  12  is operating in the warning condition when the engine is inactive. If auxiliary battery  12  is not operating in the warning condition, then the process repeats step S 212 . 
         [0029]    If, however, auxiliary battery  12  is operating in the warning condition, then in step S 216 , control unit  10  provides a warning to a user using warning unit  20 . The warning can be an audio or visual warning to indicate to the user that he should turn off or deactivate accessories  14 . The warning can also be an audio or visual warning to indicate to the user that auxiliary battery  12  has a low state of charge. The warning can also indicate to the user that the user should activate engine  4  such as by engaging key  18  with key reception unit  16  in an ENGINE ON state. By activating engine  4 , it is contemplated that engine  4  could recharge auxiliary battery  12 . 
         [0030]    In step S 218 , control unit  10  determines whether auxiliary battery  12  is operating in a shut off condition. Auxiliary battery  12  is operating in the shutoff condition when the engine is inactive and when a voltage of auxiliary battery  12  falls below a second predetermined voltage threshold, a power of auxiliary battery  12  falls below a second predetermined power threshold, and/or a current of auxiliary battery  12  falls below a second predetermined current threshold. The second voltage threshold is less than the first voltage threshold, the second power threshold is less than the first power threshold, and the second current threshold is less than the first current threshold. 
         [0031]    Thus, if the first voltage threshold was 6 volts, then the second voltage threshold can be, for example, 4 volts. If the voltage of auxiliary battery  12  was 5 volts, then auxiliary battery  12  would be operating in the warning condition but not in the shut off condition since 5 volts is greater than the second voltage threshold of 4 volts. However, if the voltage of auxiliary battery  12  had dropped to 3 volts, then auxiliary battery  12  would be operating in the shut off condition since 3 volts is less than the second voltage threshold of 4 volts. 
         [0032]    Furthermore, auxiliary battery  12  could be operating in a shutoff condition when the engine is inactive and when a second predetermined amount of time has expired from a triggering event, such as when accessories  14  is activated. The second predetermined amount of time can be a greater amount of time than the first predetermined amount of time. For example, if the first predetermined amount of time is 30 minutes and more than 40 minutes has elapsed since accessories  14  was activated, then auxiliary battery  12  is operating in the shutoff condition when the engine is inactive. If auxiliary battery  12  is not operating in the shut off condition, then the process repeats step S 212 . 
         [0033]    If, however, auxiliary battery  12  is operating in the shut off condition, then in step S 220 , control unit  10  disengages switch  26  to disconnect auxiliary battery  12  from accessories  14 . This may be especially useful when auxiliary battery  12  has a relatively low charge capacitance when compared to the electrical demands of accessories  14 . That is, when accessories  14  may drain auxiliary battery  12  in a relatively short period of time such as in an hour or a few hours. 
         [0034]    Optionally, control unit  10  can also display another warning to the user indicating that auxiliary battery  12  has been disconnected from accessories  14 . The warning can also include instructions to activate engine  4  by engaging key  18  with key reception unit  16  in an ENGINE ON state. In step  222 , the process ends. 
         [0035]    In one embodiment, switch  24  can be engaged to replenish auxiliary battery  12  at either step S 216  or step S 220 . This can be done, for example, only when control unit  10  detects that key  18  is engaged with key  16  and that there is sufficient energy within main battery  8  to replenish auxiliary battery  12 . 
         [0036]    Advantageously this can replenish auxiliary battery  12  while reducing the likelihood that main battery  8  is discharged because if key  18  is engaged with key reception unit  16 , it is contemplated that the user is present. If the user is present, then the user can activate engine  4  to recharge auxiliary battery  12 . 
         [0037]    Furthermore, if the user is not present, then it may be less critical that accessories  14  remain active or have the ability to remain active. Also, if main battery  8  is a high voltage battery, then it may be beneficial to reduce the amount of time when main battery  8  is connected to auxiliary battery  12  such as when the user is not present in automobile  2 . 
         [0038]    In another embodiment, as soon as engine  4  is activated, the process moves to step S 222  and ends. This is because as soon as engine  4  is activated, then engine  4  is used to recharge auxiliary battery  12 . This may reduce the necessity for auxiliary battery  12  to be disconnected from accessories  14 . 
         [0039]    In yet another embodiment, key  18  can engage key reception unit  16  in a third state such as an IGNITION OFF state. During the IGNITION OFF state, switch  26  is disengaged, preventing power from flowing from auxiliary battery  12  to accessories  14 . In such an embodiment, during an ACCESSORIES ON state and an ENGINE ON state, switch  26  is engaged allowing power to flow from auxiliary battery  12  to accessories  14 . 
         [0040]    Those of ordinary skill would appreciate that the various illustrative logical blocks, modules, and algorithm steps described in connection with the examples disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosed apparatus and methods. 
         [0041]    The various illustrative logical blocks, modules, and circuits described in connection with the examples disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
         [0042]    The steps of a method or algorithm described in connection with the examples disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an Application Specific Integrated Circuit (ASIC). The ASIC may reside in a wireless modem. In the alternative, the processor and the storage medium may reside as discrete components in the wireless modem. 
         [0043]    The previous description of the disclosed examples is provided to enable any person of ordinary skill in the art to make or use the disclosed methods and apparatus. Various modifications to these examples will be readily apparent to those skilled in the art, and the principles defined herein may be applied to other examples without departing from the spirit or scope of the disclosed method and apparatus. The described embodiments are to be considered in all respects only as illustrative and not restrictive and the scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.