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TECHNICAL FIELD 
     The disclosure relates to a system for controlling an access opening in a body of a vehicle in the event of a power loss. 
     BACKGROUND 
     A typical vehicle has at least one side door to provide access for vehicle occupants to the vehicle&#39;s interior. Generally, such side doors are either hinged to swing-out relative to the vehicle body or are configured to slide relative thereto. Such a side door typically has a latch mechanism for maintaining the door in a closed state until access into or egress from the vehicle is required. The door latch mechanism is typically actuated by an outside door handle to gain access to the interior of the vehicle and by an interior door handle to permit the occupant to exit the vehicle interior. 
     Additionally, vehicles frequently have enclosed cargo areas that are positioned either at the front or at the rear end of the vehicle body. The design of such cargo enclosures typically includes a hinged cargo door, such as a deck-lid or a tailgate for security and convenient access. Generally, similar to latch mechanisms of the side doors, cargo enclosure doors employ latch mechanisms for maintaining the enclosure in a closed state until access thereto is required. In modern vehicles, latch mechanisms for both the side doors and cargo doors are frequently power actuated. 
     SUMMARY 
     A system for controlling access into a vehicle in the event of loss of electrical power is disclosed. The vehicle has a vehicle body that defines a vehicle interior and a vehicle exterior, and an access opening defined by the vehicle body and configured to provide access to the vehicle interior. The vehicle also has a first door configured to selectively cover and uncover at least a portion of the access opening, a cargo enclosure defined by the body, a second door configured to selectively cover and uncover at least a portion of the cargo enclosure, and an energy storage device for generating the electrical power. The system includes a first latch configured to selectively latch and unlatch the first door. The system also includes a first switch in electrical communication with the first latch and the energy storage device and configured to operate the first latch. The system additionally includes a second latch configured to selectively latch and unlatch the second door. 
     The system also includes an actuator connecting the second door to the vehicle body and configured to operate the second door for selectively opening and closing the cargo enclosure. The system additionally includes a motor-generator mounted to the vehicle body. The motor-generator operates as an electric motor when connected to the actuator to thereby selectively cover and uncover the at least a portion of the cargo enclosure and can operate as a generator to release the first latch. Furthermore, the system includes a second switch configured to selectively connect the motor-generator to the energy storage device for operating the actuator in a first mode and disconnect the motor-generator from the energy storage device for generating electric current when the second door is operated manually to operate the first latch in a second mode. 
     The second switch may be configured as a four pole/double throw switch. 
     The system may also include a bridge rectifier configured to convert the generated electric current to flow in one direction for operating the first latch in the second mode, both when the second door is opened and when the second door is closed. 
     The actuator may be configured as a spindle drive. 
     The system may additionally include a device configured to release the second latch via manual operation. 
     The system may also include a mechanism configured to disable operation of the first latch. In such a case, operation of the motor-generator in the second mode may be configured to override the mechanism and enable operation of the first latch. 
     The mechanism may be at least one of a child lock configured to disable operation of the first latch from the vehicle interior and a double-lock configured to disable operation of the first latch from each of the vehicle interior and the vehicle exterior. 
     The second switch may be mounted to one of the vehicle body, inside the cargo enclosure, and the second door, such as on an inside surface of the second door. 
     The motor-generator may be mounted to one of the vehicle body, inside the cargo enclosure, and the second door, for example on an inside surface of the second door. 
     The cargo enclosure may be configured as a trunk and the second door may then be configured as a deck lid. 
     The second door may be configured as a tailgate hinged to the vehicle body for substantially vertical pivotable movement, i.e., a liftgate. 
     The second door may also be configured as a tailgate hinged to the rear portion of the vehicle body for substantially horizontal pivotable movement, i.e., a swing-out door. 
     A vehicle employing such a system is also provided. 
     The above features and advantages, and other features and advantages of the present disclosure, will be readily apparent from the following detailed description of the embodiment(s) and best mode(s) for carrying out the described disclosure when taken in connection with the accompanying drawings and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic top view of a vehicle having a passenger compartment and a cargo enclosure with respective access doors according to the present disclosure. 
         FIG. 2  is a partial perspective rear view of an example vehicle having a system for controlling access thereto, illustrating a three-box sedan body style having a fully-enclosed trunk and a deck lid for covering thereof. 
         FIG. 3  is a partial rear view of an alternative embodiment of the vehicle having the system for controlling access thereto, illustrating an example of a hatchback body style having a partially-enclosed trunk and a tailgate for covering thereof. 
         FIG. 4  is a schematic illustration of an example electrical circuit showing connections of various components of the system according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, wherein like reference numbers refer to like components,  FIG. 1  shows a schematic view of a motor vehicle  10  positioned relative to a road surface  12 . The vehicle  10  includes a vehicle body  14 . The vehicle body  14  defines six body sides. The six body sides include a first body end or front end  16 , an opposing second body end or rear end  18 , a first lateral body side or left side  20 , a second lateral body side or right side  22 , a top body portion  24 , which may include a vehicle roof, and an underbody portion (not shown). The left side  20  and right side  22  are disposed generally parallel to each other and with respect to a virtual longitudinal axis X of the vehicle  10 , and span the distance between the front end  16  and the rear end  18 . The vehicle  10  also includes a system for controlling access into the subject vehicle in the event of loss of electrical power, which will be described in detail below. 
     The body sides  16 ,  18 ,  20 ,  22 ,  24 , together with the underbody portion define a vehicle exterior  26 . The body  14  also defines a vehicle interior  28  that includes a passenger compartment  28 A. The passenger compartment  28 A is adapted to accommodate vehicle passengers and their belongings. As shown in  FIG. 1 , the vehicle  10  also includes at least one access opening  30  that is defined by the body  14  and provides access to the vehicle interior  28 . As shown, the vehicle body  14  defines four individual access openings  30 . The vehicle  10  also includes a first door  32  for each of the access openings  30 . Each first door  32  is configured to selectively cover and uncover at least a portion of the respective access opening  30  in order to control passage between the vehicle exterior  26  and the vehicle interior  28 . The vehicle  10  also includes a cargo enclosure  34  that is defined by the body  14 . A second door  36  is configured to selectively cover and uncover at least a portion of the cargo enclosure  34 . 
     The cargo enclosure  34  may be configured as a separate compartment, such as a fully-enclosed trunk, for instance in a traditional three-box sedan body style, while the second door  36  may be configured as a hinged deck lid, as shown in  FIG. 2 . The second door  36  may also be configured as a tailgate (shown in  FIG. 3 ) for a fully or partially-enclosed trunk, wherein at least one side of the trunk is open to the passenger compartment  28 A. As shown, the tailgate-type of a second door  36  is hinged at the rear end  18  of the vehicle body  14  for substantially vertical pivotable movement, such as a liftgate. Additionally, the second door  36  may be configured as a tailgate hinged to the rear end  18  of the vehicle body  14  for substantially horizontal pivotable movement, such as a swing-out door (not shown). Although the cargo enclosure  34  is primarily described and shown throughout the Figures as being arranged at the rear  18  of the vehicle body  14 , such a cargo enclosure may also be arranged proximate the front end  16 . Such a front-positioned cargo enclosure  34  (not shown) may, for example, be used in a rear-engine or a mid-engine vehicle, as understood by those skilled in the art. The disclosed tailgate is of the type that is frequently used for access to the interiors and storage compartments in vans, station wagons, and sport utility vehicles (SUVs). 
     The vehicle  10  also includes an energy storage device  38  (shown in  FIG. 1 ), such as a battery, for generating electrical power used to operate various vehicle systems, such as powertrain, lighting, and heating, ventilation, and air conditioning (HVAC). As shown in  FIG. 2 , the vehicle  10  also includes a first latch  40  for each of the first doors  32 . Each first latch  40  is configured to selectively latch and unlatch the first door  32 . The first latch  40  may be additionally configured to selectively lock and unlock the first door  32 , thus selectively disabling and enabling operation of the first door. The vehicle  10  also includes a first switch  42  in electrical communication with each of the first latch  40  and the energy storage device  38 . The first switch  42  is configured to operate the first latch  40  via an electric motor  43  in connection with the energy storage device  38 . Accordingly, each first latch  40  is power operated to facilitate access to the respective access openings  30  via first doors  32  by using the electrical power generated by the energy storage device  38 . The first switch  42  may be configured as a door handle, a pushbutton, or any other device that may be conveniently operated to gain access to the passenger compartment  28 A. 
     Additionally, the vehicle  10  also includes a second latch  44  configured to selectively latch and unlatch the second door  36  and an actuator  46 . The second latch  44  may be additionally configured to selectively lock and unlock the second door  36 , thus selectively disabling and enabling operation of the second door. The actuator  46  connects the second door  36  to the vehicle body  14  and is configured to operate or move the second door for selectively opening and closing the cargo enclosure  34 . The actuator  46  may be configured as a spindle drive, as shown in  FIGS. 2 and 3 . Either one or a plurality of such actuators  46  may be used to operate the second door  36 . Each such actuator  46  is operatively connected to the vehicle body  14  via a first end  46 - 1 , and to the second door  36  via a second end  46 - 2 . As understood by those skilled in the art, a spindle drive utilizes a lead screw to translate radial motion into linear motion. In place of the described spindle drive, other devices that are capable of translating radial motion into linear motion, such as a rack and pinion, may also be employed for each actuator  46 . 
     As shown in  FIGS. 2 and 3 , the actuator  46  includes a motor-generator  48 . The motor-generator  48  of the actuator  46  is power operated to facilitate access to the cargo enclosure  34  via the second door  36  by using the electrical power generated by the energy storage device  38 . A second switch  50  is arranged on the vehicle  10  and configured to selectively connect the motor-generator  48  to and disconnect the motor-generator from the energy storage device  38 . The second switch  50  may be mounted to either the vehicle body  14 , inside the cargo enclosure  34  (as shown in  FIG. 2 ), or to the second door  36 , such as on an inside surface  36 A (as shown in  FIG. 3 ). The second switch  50  may be configured as a four pole/double throw (4PDT) switch. 
     As understood by those skilled in the art, a 4PDT switch is a transfer switch that is designed to power an electric load selectively from multiple sources. Double throw means the switch can be placed into two distinct “on” positions, P 1  and P 2  (an “off” position is not counted). Four pole means the switch transfers four line wires, i.e., poles. The 4PDT switch is configured to disconnect the electric load from an electric power source before connecting the load to another power source. In the specific embodiment of the second switch  50 , the P 1  position may be one that connects the motor-generator  48  to the energy storage device  38  and the P 2  position may disconnect the motor-generator  48  from the energy storage device. The second switch  50  may also be configured as a combination of multiple switches, such as a pair of double pole/double throw (DPDT) switches, each of which transfers two line wires or poles. 
     A system  52  for controlling access into the vehicle  10  in the event of loss of electrical power from the energy storage device  38  includes each of the first latch  40 , first switch  42 , second latch  44 , the actuator  46 , the motor-generator  48 , and the second switch  50 . The system  52  selectively operates the motor-generator  48  either as an electric motor or as a generator. The second switch  50  connects the motor-generator  48  to the energy storage device  38  for operating the actuator  46  in a first mode, wherein the motor-generator drives the actuator  46 . The second switch  50  is also configured to disconnect the motor-generator  48  from the energy storage device  38  for generating electric current when the second door  36  is operated manually. Such manual operation of the second door  36  drives the motor-generator  46  as a generator via the actuator  46  for operating the first latch  40  in a second mode. Accordingly, the motor-generator  48  operates as an electric motor when connected to the actuator  46  and the energy storage device  38  to thereby selectively cover and uncover the cargo enclosure  34 , and, in the event of loss of electrical power, operates as a generator to release the first latch  40  when manually driven via the second door  36 . 
     As shown in  FIG. 2 , the system  52  may also include a device  54  configured to release the second latch  44  via manual operation. For example, the device  54  may be configured as a key-lock (shown in  FIG. 2 ) and/or a mechanical lever (shown in  FIG. 3 ) that is accessible from the vehicle exterior  26 . The device  54  may be positioned on an exterior surface  36 B of the second door  36 , such that an operator may manually trigger opening of the second door from outside the vehicle  10 . In addition to being manually operated by the device  54 , the second latch  44  may be power actuated via a separate switch  56  that is arranged inside the passenger compartment  28 A, as shown in  FIG. 3 . 
     As shown in  FIG. 2 , the second door  36  may include a feature  58  on the inside surface  36 A, such as a specifically configured handle, pad, or depression. The feature  58  is configured to provide a convenient location for the operator to apply a force for manually opening the second door  36 , such as proximate to a side edge  36 C of the second door. In the event the second door  36  includes a trim panel  36 D (shown in  FIG. 2 ) arranged on the inside surface  36 A, the feature  58  may be incorporated into such a trim panel. The second switch  50  may be arranged proximate to the feature  58 , such as adjacent to or part of the pad, or in the depression. 
     The system  52  may additionally include a bridge rectifier  60  as part of an electrical circuit  64  (shown in  FIG. 4 ) that includes the second switch  50 , the motor-generator  48 , and the energy storage device  38 . The bridge rectifier  60  is configured to convert the electric current generated by the motor-generator  48  in the second mode to flow in one direction for operating the first latch  40  via the second switch  50 , both when the second door  36  is manually opened and manually closed. As shown in  FIGS. 1  and  4 , the system  52  may also include an Electronic Control Module (ECM)  62  that controls various components of the system  52 . The ECM  62  includes an input block  62 A for electrical input from the energy storage device  38 , the first switch  42 , and the switch  56 , as well as an output block  62 B for electrical output to the second switch  50 .  FIG. 4  schematically illustrates the electrical circuit  64  that includes connections between various components of the system  52 . 
     The system  52  may additionally include a mechanism  66  that functions to disable operation of the first latch  40 . The mechanism  66  may be configured as a child lock that disables operation of the first latch  40  from the passenger compartment  28 A, thereby ensuring that children do not inadvertently release the first latch at an inopportune instance. The mechanism  66  may be configured as a double-lock configured to disable operation of the first latch  40  from each of the passenger compartment  28 A and the vehicle exterior  26 . Such a double-lock mechanism  66  can function as both a child lock and as a means to thwart unauthorized entry into the vehicle, as understood by those skilled in the art. As part of operating the motor-generator  48  in the second mode, the system  52  may be configured to override the mechanism  66  and enable operation of the first latch  40 . 
     Accordingly, in the event of loss of electrical power from the energy storage device  38 , the system  52  permits an operator to initially open the second door  36  via the device  54 . Then, following the second switch  50  being transferred from the P 1  position to the P 2  position, manual lifting of the second door  36  will result in driving the motor-generator  48  in generator mode and operating the actuator  46  in the second mode. Thus, driving the motor-generator  48  as a generator provides electrical current to power one or more of the first latches  40  in order to gain access into the vehicle  10  through the respective first door  32  even if the electrical power from the energy storage device  38  is insufficient. 
     The detailed description and the drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed disclosure have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims. Furthermore, the embodiments shown in the drawings or the characteristics of various embodiments mentioned in the present description are not necessarily to be understood as embodiments independent of each other. Rather, it is possible that each of the characteristics described in one of the examples of an embodiment can be combined with one or a plurality of other desired characteristics from other embodiments, resulting in other embodiments not described in words or by reference to the drawings. Accordingly, such other embodiments fall within the framework of the scope of the appended claims.

Summary:
A system for controlling access into a vehicle in the event of loss of electrical power is disclosed. The vehicle has an access opening into the vehicle&#39;s interior with a first door for access thereto, a cargo enclosure with a second door therefor, and an energy storage device for generating the electrical power. A first latch selectively latches and unlatches the first door, while a first switch operates the first latch. A second latch selectively latches and unlatches the second door, while an actuator connects the second door to the vehicle body and selectively opens and closes the second door. A second switch selectively connects a motor-generator to the energy storage device for operating the actuator in a first mode and disconnects the motor-generator from the energy storage device for generating electric current when the second door is operated manually to operate the first latch in a second mode.