Abstract:
A method according to an exemplary aspect of the present disclosure includes, among other things, detecting a battery fault of a battery of an electrified vehicle, activating a HVAC system ON, commanding the HVAC system to a fresh air mode, communicating fresh air into a passenger cabin, and expelling battery vent byproducts from the passenger cabin through at least one air extractor vent during key-on or key-off states.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to an electrified vehicle, and more particularly, but not exclusively, to a cabin venting system and method for actively venting battery vent byproducts from a passenger cabin of an electrified vehicle. 
       BACKGROUND 
       [0002]    Hybrid electric vehicles (HEV&#39;s), plug in hybrid electric vehicles (PHEV&#39;s), battery electric vehicles (BEV&#39;s), fuel cell vehicles and other known electrified vehicles differ from conventional motor vehicles in that are powered by one or more electric machines (i.e., electric motors and/or generators) instead of or in addition to an internal combustion engine. High voltage current is typically supplied by one or more batteries that store electrical power for powering the electric machine(s). 
         [0003]    The high voltage batteries of an electrified vehicle typically include one or more lithium-ion battery cells. Battery vent byproducts may be expelled from one or more of the lithium-ion battery cells in response to a battery fault during drive as well as during a plug-in charge. These byproducts can migrate into a passenger cabin of the electrified vehicle and therefore may need to be purged to outside atmosphere. 
       SUMMARY 
       [0004]    A method according to an exemplary aspect of the present disclosure includes, among other things, detecting a battery fault of a battery of an electrified vehicle, activating a HVAC system ON, commanding the HVAC system to a fresh air mode, communicating fresh air into a passenger cabin, and expelling battery vent byproducts from the passenger cabin through at least one air extractor vent during key-on or key-off states. 
         [0005]    In a further non-limiting embodiment of the foregoing method, the method of detecting includes evaluating voltages and temperature of at least one battery cell of the battery. 
         [0006]    In a further non-limiting embodiment of either of the foregoing methods, if the electrified vehicle is on, the step of activating the HVAC system includes communicating a request signal from a first control module to a second control module and communicating a command signal from the second control module to the HVAC system to activate the HVAC system. 
         [0007]    In a further non-limiting embodiment of any of the foregoing methods, if the electrified vehicle is off, waking up a first control module to precondition the HVAC system so the HVAC system stays ON during the key-off state. 
         [0008]    In a further non-limiting embodiment of any of the foregoing methods, the method of waking up the first control module includes communicating a first wake up signal from a battery electronic control module to the first control module and communicating a second wake up signal from the first control module to a second control module. 
         [0009]    In a further non-limiting embodiment of any of the foregoing methods, the method of commanding includes opening a fresh air door of the HVAC system and actuating a fan of the HVAC system to an on position. 
         [0010]    In a further non-limiting embodiment of any of the foregoing methods, the steps of opening and actuating are performed for a predefined amount of time. 
         [0011]    In a further non-limiting embodiment of any of the foregoing methods, the step of commanding includes opening a fresh air door of the HVAC system for a predefined amount of time. 
         [0012]    In a further non-limiting embodiment of any of the foregoing methods, the step of commanding includes actuating a fan of the HVAC system to an on position at a predefined speed and for a predefined amount of time. 
         [0013]    In a further non-limiting embodiment of any of the foregoing methods, the step of communicating includes drawing in the fresh air from a vehicle exterior. 
         [0014]    In a further non-limiting embodiment of any of the foregoing methods, the method includes deactivating the HVAC system after the step of expelling. 
         [0015]    In a further non-limiting embodiment of any of the foregoing methods, the method includes deactivating the HVAC system after a predefined amount of time. 
         [0016]    A cabin venting system according to another exemplary aspect of the present disclosure includes, among other things, a battery that includes a battery electronic control module and a second control module in communication with the battery electronic control module. A HVAC system is operable in a fresh air mode in response to a command signal from the second control module. At least one air extractor vent is configured to expel battery vent byproducts in response to operation of the HVAC system in the fresh air mode. 
         [0017]    In a further non-limiting embodiment of the foregoing cabin venting system, the second control module is a powertrain control module or a combined body control module/powertrain control module. 
         [0018]    In a further non-limiting embodiment of either of the foregoing cabin venting systems, the HVAC system includes a fresh air door and a fan. 
         [0019]    In a further non-limiting embodiment of any of the foregoing cabin venting systems, the fresh air door is movable to an open position and the fan is actuable to an on position in response to the command signal. 
         [0020]    An electrified vehicle according to an exemplary aspect of the present disclosure includes, among other things, a passenger cabin and a cabin venting system for purging the passenger cabin. The cabin venting system includes a battery having a first control module, a second control module in communication with the first control module and a HVAC system operable in a fresh air mode in response to a command signal from either the first control module or the second control module to expel battery vent byproducts from the passenger cabin. 
         [0021]    In a further non-limiting embodiment of the foregoing electrified vehicle, the first control module is a battery electronic control module and the second control module is a powertrain control module. 
         [0022]    In a further non-limiting embodiment of either of the foregoing electrified vehicles, the HVAC system includes a control unit, a fresh air door and a fan. 
         [0023]    In a further non-limiting embodiment of any of the foregoing electrified vehicles, at least one air extractor vent is configured to expel the battery vent byproducts in response to operation of the HVAC system in the fresh air mode. 
         [0024]    The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible. 
         [0025]    The various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  schematically illustrates a powertrain of an electrified vehicle. 
           [0027]      FIG. 2  illustrates a cabin venting system that can be incorporated into an electrified vehicle. 
           [0028]      FIG. 3  schematically illustrates a method for actively venting a passenger cabin of an electrified vehicle. 
           [0029]      FIG. 4  schematically illustrates additional features of a method for actively venting a passenger cabin of an electrified vehicle. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    This disclosure relates to a cabin venting system and method for use in an electrified vehicle. An exemplary cabin venting system is configured to selectively command an HVAC system to continue operating in a fresh air mode in order to expel battery vent byproducts from a passenger cabin of the electrified vehicle after a transition to a key-off state without a vehicle operator turning the key off. The HVAC may continue to communicate fresh air into the passenger cabin in order to expel the battery byproducts through at least one air extractor vent. The cabin venting system of this disclosure is an active system that can control the HVAC system during a battery fault at drive or during a plug-in charge without requiring any direct vehicle operator participation. These and other features are discussed in greater detail herein. 
         [0031]      FIG. 1  schematically illustrates a powertrain  10  for an electrified vehicle  12 , such as a HEV. Although depicted as a HEV, it should be understood that the concepts described herein are not limited to HEV&#39;s and could extend to other electrified vehicles, including but not limited to, PHEV&#39;s, BEV&#39;s, and fuel cell vehicles. 
         [0032]    In one embodiment, the powertrain  10  is a powersplit system that employs a first drive system that includes a combination of an engine  14  and a generator  16  (i.e., a first electric machine) and a second drive system that includes at least a motor  36  (i.e., a second electric machine), the generator  16  and a battery  50 . For example, the motor  36 , the generator  16  and the battery  50  may make up an electric drive system  25  of the powertrain  10 . The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels  30  of the electrified vehicle  12 , as discussed in greater detail below. 
         [0033]    The engine  14 , such as an internal combustion engine, and the generator  16  may be connected through a power transfer unit  18 . In one non-limiting embodiment, the power transfer unit  18  is a planetary gear set. Of course, other types of power transfer units, including other gear sets and transmissions, may be used to connect the engine  14  to the generator  16 . The power transfer unit  18  may include a ring gear  20 , a sun gear  22  and a carrier assembly  24 . The generator  16  is driven by the power transfer unit  18  when acting as a generator to convert kinetic energy to electrical energy. The generator  16  can alternatively function as a motor to convert electrical energy into kinetic energy, thereby outputting torque to a shaft  26  connected to the carrier assembly  24  of the power transfer unit  18 . Because the generator  16  is operatively connected to the engine  14 , the speed of the engine  14  can be controlled by the generator  16 . 
         [0034]    The ring gear  20  of the power transfer unit  18  may be connected to a shaft  28  that is connected to vehicle drive wheels  30  through a second power transfer unit  32 . The second power transfer unit  32  may include a gear set having a plurality of gears  34 A,  34 B,  34 C,  34 D,  34 E, and  34 F. Other power transfer units may also be suitable. The gears  34 A- 34 F transfer torque from the engine  14  to a differential  38  to provide traction to the vehicle drive wheels  30 . The differential  38  may include a plurality of gears that enable the transfer of torque to the vehicle drive wheels  30 . The second power transfer unit  32  is mechanically coupled to an axle  40  through the differential  38  to distribute torque to the vehicle drive wheels  30 . 
         [0035]    The motor  36  can also be employed to drive the vehicle drive wheels  30  by outputting torque to a shaft  46  that is also connected to the second power transfer unit  32 . In one embodiment, the motor  36  and the generator  16  are part of a regenerative braking system in which both the motor  36  and the generator  16  can be employed as motors to output torque. For example, the motor  36  and the generator  16  can each output electrical power to a high voltage bus  48  and the battery  50 . The battery  50  may be a high voltage battery that is capable of outputting electrical power to operate the motor  36  and the generator  16 . Other types of energy storage devices and/or output devices can also be incorporated for use with the electrified vehicle  12 . 
         [0036]    The motor  36 , the generator  16 , the power transfer unit  18 , and the power transfer unit  32  may generally be referred to as a transaxle  42 , or transmission, of the electrified vehicle  12 . Thus, when a driver selects a particular shift position, the transaxle  42  is appropriately controlled to provide the corresponding gear for advancing the electrified vehicle  12  by providing traction to the vehicle drive wheels  30 . 
         [0037]    The powertrain  10  may additionally include a control system  44  for monitoring and/or controlling various aspects of the electrified vehicle  12 . For example, the control system  44  may communicate with the electric drive system  25 , the power transfer units  18 ,  32  or other components to monitor and/or control the electrified vehicle  12 . The control system  44  includes electronics and/or software to perform the necessary control functions for operating the electrified vehicle  12 . In one embodiment, the control system  44  is a combination vehicle system controller and powertrain control module (VSC/PCM). Although it is shown as a single hardware device, the control system  44  may include multiple controllers in the form of multiple hardware devices, or multiple software controllers within one or more hardware devices. 
         [0038]    A controller area network (CAN)  52  allows the control system  44  to communicate with the transaxle  42 . For example, the control system  44  may receive signals from the transaxle  42  to indicate whether a transition between shift positions is occurring. The control system  44  may also communicate with a battery control module of the battery  50 , or other control devices. 
         [0039]    Additionally, the electric drive system  25  may include one or more controllers  54 , such as an inverter system controller (ISC). The controller  54  is configured to control specific components within the transaxle  42 , such as the generator  16  and/or the motor  36 , such as for supporting bidirectional power flow. In one embodiment, the controller  54  is an inverter system controller combined with a variable voltage converter (ISC/VVC). 
         [0040]    The battery  50  may include one or more battery cells  56 , such as lithium-ion battery cells. The battery cells  56  are shown schematically in  FIG. 1 . The battery cells  56  may overheat or be damaged as a result of a vehicle accident or other fault in the vehicle or battery. One or more of the damaged battery cells  56  can emit battery vent byproducts in response to the battery fault. The battery vent byproducts can include carbon monoxide, hydrogen and/or other byproducts that may need removed from the electrified vehicle  12  during drive or plug-in charge. 
         [0041]      FIG. 2  schematically illustrates a block diagram of a cabin venting system  60  that can be incorporated into an electrified vehicle, such as electrified vehicle  12  of  FIG. 1 . The cabin venting system  60  may be activated in response to a battery fault in order to expel battery vent byproducts B from a passenger cabin (see  FIGS. 3 and 4 ) of the electrified vehicle  12 . For example, the cabin venting system  60  may employ a battery  50 , such as the high voltage battery of the electrified vehicle  12 , a body control module (BCM)  62 , a powertrain control module (PCM)  64 , and a HVAC system  66  that operate together to perform a cabin air purge in response to a battery fault of the battery  50 . The BCM  62  and the PCM  64  also perform other functions related to an electrified vehicle operation beyond those involving the cabin venting system  60 . In another embodiment, the BCM  62  and the PCM  64  are a combined body control module/powertrain control module. 
         [0042]    One or more battery cells  56  of the battery  50  may emit battery vent byproducts B in response to a battery fault. The battery vent byproducts B can escape from the battery cell(s)  56  into a venting chamber  55  of the battery  50 . The battery vent byproducts B are taken from the venting chamber  55  and sent to outside atmosphere (i.e., exterior to the vehicle) by the cabin venting system  60 . 
         [0043]    The battery  50  includes a battery electronic control module (BECM)  68  (i.e., a first control module) for monitoring the status of the battery  50  and for requesting the activation of the cabin venting system  60  over a controlled area network (CAN). For example, depending upon whether the electrified vehicle  12  is in a key-on or a key-off condition, the BECM  68  can communicate request signals to either the BCM  62  (i.e., a second control module) or the PCM  64  (i.e., a third control module), which may then send command signals to the HVAC system  66 . In one embodiment, during a key-on condition, the BECM  68  communicates a request signal to the PCM  64  and the PCM  64  then communicates a command signal to a control unit  70  of the HVAC system  66  in order to activate the HVAC system  66  for responding to a battery fault. Alternatively, during a key-off condition, which may occur during plug-in charge of the battery  50 , the BECM  68  may communicate a signal to the BCM  62  to wake-up the PCM  64  for enabling pre-conditioning so that the BCM  62  will enable the blower relays to force the HVAC system  66  to remain “ON” during the key-off state. The BECM  68 , the BCM  62 , the PCM  64  and the HVAC system  66  each include the necessary hardware and software for utilizing network management to communicate with one another. 
         [0044]      FIGS. 3 and 4 , with continued reference to  FIGS. 1 and 2 , schematically illustrate a method of utilizing the cabin venting system  60  to actively vent a passenger cabin  72  of an electrified vehicle  12 . For example, the method can be performed in order to expel battery vent byproducts B that have entered the passenger cabin  72  from the venting chamber  55  of the battery  50  after a battery fault. As further detailed below, a detection and communication portion of the method is shown in  FIG. 3 , and  FIG. 4  illustrates a mitigation portion of the exemplary method. 
         [0045]    Referring to  FIG. 3 , the method begins in response to detecting a battery fault of the battery  50 . Battery vent byproducts B may escape into the passenger cabin  72  in response to a battery fault and therefore may need purged from the passenger cabin  72 . The BECM  68  of the battery  50  can detect battery faults. In one embodiment, the BECM  68  evaluates voltages and temperatures of one or more battery cells  56  of the battery  50  in order to detect whether a battery fault, such as a battery cell venting event, has occurred. The BECM  68  may be programmed with the necessary algorithms for performing such an evaluation. 
         [0046]    In response to detecting a battery fault, the BECM  68  may use network management to communicate with other components of the cabin venting system  60 . For example, if the electrified vehicle  12  is on, the BECM  68  communicates a command signal to the control unit  70  over a first communication path C 1  through the PCM  64  to activate the HVAC system  66 . Alternatively, if the electrified vehicle  12  is in a key-off state, the BECM  68  may communicate a first wake up signal to the BCM  62  over a second communication path C 2 . The BCM  62  may then communicate a second wake up signal to the PCM  64  over the second communication path C 2 . Finally, one awoken, the PCM  64  communicates a command signal to control unit  70  of the HVAC system  66  to enable preconditioning of the HVAC system  66 . 
         [0047]    In the embodiment shown by  FIG. 3 , a fresh air door  74  and a fan  76  of the HVAC system  66  are in closed and off positions, respectively. In addition, an air extractor vent  86  of the HVAC system  66  is closed. 
         [0048]      FIG. 4  schematically illustrates a mitigation portion of the method for expelling battery vent byproducts B that have entered the passenger cabin  72  after a battery fault. The mitigation portion occurs in response to receiving a request from the BECM  68  to the PCM  64 . The PCM  64  may accept the request by commanding the HVAC system  66  to activate the cabin venting system  60 . Once a command signal has been received by the control unit  70 , the HVAC system  66  is activated and commanded to a fresh air mode. In the fresh air mode, the fresh air door  74  is moved to an open position to permit fresh air  78  to enter inside the electrified vehicle  12 . In one embodiment, the fresh air  78  is drawn from a vehicle exterior  80  that is completely remote from the passenger cabin  72 . 
         [0049]    The fan  76  of the HVAC system  66  may also be actuated to an “on” position in response to receiving one of the command signals from either the BECM  68  or the PCM  64 . The fan  76  may rotate to communicate the fresh air  78  into the passenger cabin  72 . The fresh air  78  is circulated through the passenger cabin  72  where it intermixes with the battery vent byproducts B. The fan  76  may be operated at a predefined speed for forcing the fresh air  78  through the passenger cabin  72 . 
         [0050]    In one embodiment, the HVAC system  66  is located near a front  84  of the electrified vehicle  12  and one or more air extractor vents  86  are located near a rear  82  of the electrified vehicle  12 . Although only one vent is shown, the cabin venting system  60  of the electrified vehicle  12  may be equipped with numerous air extractor vents  86  located throughout the electrified vehicle  12 . 
         [0051]    The fan  76  forces the fresh air  78  and the battery vent byproducts B through the passenger cabin  72  toward the rear  82  of the electrified vehicle  12 . The battery vent byproducts B may be expelled through at least one air extractor vent  86 , thereby purging the battery vent byproducts B from the passenger cabin  72 . In one embodiment, the air extractor vents  86  are plastic flapper valves, although other configurations are also contemplated. In other words, the battery vent byproducts B are not expelled by lowering the windows of the electrified vehicle  12 , which may be undesirable in certain climates or during certain situations, but are instead displaced through the air extractor vents  86  without requiring any active vehicle operator participation. 
         [0052]    The fresh air door  74  may remain open and the fan  76  left in the “on” position for a predefined amount of time. The predefined amount of time may vary depending on the amount of battery vent byproducts B that have entered the passenger cabin  72 . In one non-limiting embodiment, the predefined amount of time is approximately 90 seconds. However, other durations are contemplated as within the scope of this disclosure. The HVAC system  66  may be automatically deactivated once the predefined amount of time has expired and/or the battery vent byproducts B have been purged from the passenger cabin  72 . 
         [0053]    Although the different non-limiting embodiments are illustrated as having specific components or steps, the embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments. 
         [0054]    It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should be understood that although a particular component arrangement is disclosed and illustrated in these exemplary embodiments, other arrangements could also benefit from the teachings of this disclosure. 
         [0055]    The foregoing description shall be interpreted as illustrative and not in any limiting sense. A worker of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. For these reasons, the following claims should be studied to determine the true scope and content of this disclosure.