Abstract:
A method according to an exemplary aspect of the present disclosure includes, among other things, controlling an electrified vehicle by closing a contactor prior to a key on condition of the electrified vehicle.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to an electrified vehicle, and more particularly, but not exclusively, to a vehicle system and method for closing a contactor prior to starting the vehicle. 
       BACKGROUND 
       [0002]    Generally, electrified vehicles differ from conventional motor vehicles in that they are selectively driven using one or more battery powered electric machines. Conventional motor vehicles, by contrast, rely exclusively on an internal combustion engine to drive the vehicle. Electrified vehicles may use electric machines instead of, or in addition to, internal combustion engines. The electric machines are typically powered by high voltage batteries. 
         [0003]    Electrified vehicles may utilize one or more contactors that isolate energy stored in the high voltage batteries from other vehicle loads. For example, the contactors may act as high voltage relays for switching supply voltages to other high voltage components on the vehicle (e.g., electric machines, A/C compressor, PTC heater, DCDC converter, etc.). The contactors connect the battery to a high voltage bus during normal vehicle operation in order to power the electric machine(s). 
       SUMMARY 
       [0004]    A method according to an exemplary aspect of the present disclosure includes, among other things, controlling an electrified vehicle by closing a contactor prior to a key on condition of the electrified vehicle. 
         [0005]    In a further non-limiting embodiment of the foregoing method, the controlling step includes closing the contactor in response to an early wake trigger. 
         [0006]    In a further non-limiting embodiment of either of the foregoing methods, the early wake trigger includes applying a brake of the electrified vehicle. 
         [0007]    In a further non-limiting embodiment of any of the foregoing methods, the early wake trigger includes positioning a key in an ignition of the electrified vehicle. 
         [0008]    In a further non-limiting embodiment of any of the foregoing methods, the early wake trigger includes at least one of unlocking a door of the electrified vehicle, sitting in a seat of the electrified vehicle, detecting a key in proximity to the electrified vehicle, and opening a door of the electrified vehicle. 
         [0009]    A method according to another exemplary aspect of the present disclosure includes, among other things, closing a contactor in response to an early wake trigger to reduce a vehicle start time associated with an electrified vehicle. 
         [0010]    In a further non-limiting embodiment of the foregoing method, the early wake trigger occurs prior to a key on condition of the electrified vehicle. 
         [0011]    In a further non-limiting embodiment of either of the foregoing methods, the early wake trigger includes applying a brake of the electrified vehicle. 
         [0012]    In a further non-limiting embodiment of any of the foregoing methods, the early wake trigger includes positioning a key in an ignition of the electrified vehicle. 
         [0013]    In a further non-limiting embodiment of any of the foregoing methods, the closing step occurs prior to a key on condition of the electrified vehicle. 
         [0014]    In a further non-limiting embodiment of any of the foregoing methods, the method includes awakening various systems of the electrified vehicle prior to the closing step. 
         [0015]    In a further non-limiting embodiment of any of the foregoing methods, the method includes communicating a wake-up signal from a first control unit to a second control unit, communicating a command signal from the second control unit to a third control unit and commanding the closing step with the third control unit in response to receiving the command signal. 
         [0016]    In a further non-limiting embodiment of any of the foregoing methods, the first control unit is a body control module, the second control unit is a hybrid powertrain control module, and the third control unit is a battery electronic control module. 
         [0017]    In a further non-limiting embodiment of any of the foregoing methods, the wake-up signal is communicated in response to sensing the early wake trigger. 
         [0018]    In a further non-limiting embodiment of any of the foregoing methods, the method includes opening the contactor if a start request is not received after a threshold amount of time has passed. 
         [0019]    A vehicle system according to another exemplary aspect of the present disclosure includes, among other things, a contactor and a control unit configured to close the contactor in response to an early wake trigger. 
         [0020]    In a further non-limiting embodiment of the foregoing vehicle system, the contactor is commanded closed to connect a battery to an electric machine over a high voltage bus. 
         [0021]    In a further non-limiting embodiment of either of the foregoing vehicle systems, at least one sensor is configured to detect the early wake trigger. 
         [0022]    In a further non-limiting embodiment of any of the foregoing vehicle systems, the system includes a second control unit and a third control unit, the second control unit configured to communicate a wake-up signal to the third control unit in response to the early wake trigger. 
         [0023]    In a further non-limiting embodiment of any of the foregoing vehicle systems, the third control unit is configured to communicate a command signal for closing the contactor to the control unit in response to receiving the wake-up signal. 
         [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 vehicle system of an electrified vehicle. 
           [0028]      FIG. 3  schematically illustrates an exemplary start-up sequence of an electrified vehicle. 
           [0029]      FIG. 4  illustrates a vehicle system according to another embodiment of this disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    This disclosure relates to a vehicle system that closes a contactor in response to an early wake trigger to reduce electrified vehicle start times. For example, the contactor may be closed prior to starting the electrified vehicle in response to sensing that a driver has applied the vehicle brakes, positioned a key in an ignition of the vehicle, or in response to any other early wake trigger. Closing the contactors at early wake reduces the amount of time necessary to ready the vehicle to drive. 
         [0031]      FIG. 1  schematically illustrates a powertrain  10  of an electrified vehicle  12 . Although depicted as a hybrid electric vehicle (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, plug-in hybrid electric vehicles (PHEV&#39;s), battery electric vehicles (BEV&#39;s), and modular hybrid transmission vehicles. 
         [0032]    In one embodiment, the powertrain  10  is a powersplit powertrain system that employs a first drive system and a second drive system. The first drive system includes a combination of an engine  14  and a generator  18  (i.e., a first electric machine). The second drive system includes at least a motor  22  (i.e., a second electric machine), the generator  18 , and a battery  24 . In this embodiment, the second drive system is considered an electric drive system of the powertrain  10 . The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels  28  of the electrified vehicle  12 . 
         [0033]    The engine  14 , which is an internal combustion engine in this embodiment, and the generator  18  may be connected through a power transfer unit  30 , such as 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  18 . In one non-limiting embodiment, the power transfer unit  30  is a planetary gear set that includes a ring gear  32 , a sun gear  34 , and a carrier assembly  36 . 
         [0034]    The generator  18  can be driven by the engine  14  through the power transfer unit  30  to convert kinetic energy to electrical energy. The generator  18  can alternatively function as a motor to convert electrical energy into kinetic energy, thereby outputting torque to a shaft  38  connected to the power transfer unit  30 . Because the generator  18  is operatively connected to the engine  14 , the speed of the engine  14  can be controlled by the generator  18 . 
         [0035]    The ring gear  32  of the power transfer unit  30  may be connected to a shaft  40 , which is connected to vehicle drive wheels  28  through a second power transfer unit  44 . The second power transfer unit  44  may include a gear set having a plurality of gears  46 . Other power transfer units may also be suitable. The gears  46  transfer torque from the engine  14  to a differential  48  to ultimately provide traction to the vehicle drive wheels  28 . The differential  48  may include a plurality of gears that enable the transfer of torque to the vehicle drive wheels  28 . In one embodiment, the second power transfer unit  44  is mechanically coupled to an axle  50  through the differential  48  to distribute torque to the vehicle drive wheels  28 . 
         [0036]    The motor  22  (i.e., the second electric machine) can also be employed to drive the vehicle drive wheels  28  by outputting torque to a shaft  52  that is connected to the second power transfer unit  44 . In one embodiment, the motor  22  and the generator  18  cooperate as part of a regenerative braking system in which both the motor  22  and the generator  18  can be employed as motors to output torque. For example, the motor  22  and the generator  18  can each output electrical power to the battery  24 . 
         [0037]    The battery  24  is one exemplary type of an electrified vehicle battery assembly and may take the form of a high voltage battery that is capable of outputting electrical power to operate the motor  22  and/or the generator  18 . Other types of energy storage devices and/or output devices can also be used to supply power within the electrified vehicle  12 . 
         [0038]    The powertrain  10  may additionally include a control system  58  for monitoring and/or controlling various aspects of the electrified vehicle  12 . For example, the control system  58  may communicate with the electric drive system, the power transfer units  30 ,  44  or other components to monitor and/or control the electrified vehicle  12 . The control system  58  includes electronics and/or software to perform the necessary control functions for operating the electrified vehicle  12 . In one non-limiting embodiment, the control system  58  is a combination vehicle system controller and powertrain control module (VSC/PCM). Although it is shown as a single hardware device, the control system  58  may include multiple controllers in the form of multiple hardware devices, or multiple software controllers within one or more hardware devices. 
         [0039]    A controller area network (CAN)  60  allows the control system  58  to communicate with the powertrain  10 . For example, the control system  58  may receive signals from the powertrain  10  to indicate whether a transition between shift positions is occurring. The control system  58  may also communicate with a battery control module of the battery  24 , or other control devices. 
         [0040]    The powertrain  10  may additionally include one or more contactors  56  as part of a contactor assembly that acts as a high voltage relay for switching supply currents that are communicated to the motor  22  and/or the generator  18 . The contactors  56  may be selectively moved between an open position and a closed position to disconnect/connect the battery  24  to the motor  22  and/or generator  18 , or other loads, over a high voltage bus  62 . The contactors  56  are typically closed during a drive cycle of the electrified vehicle  12 . Closing the contactors  56  permits electrical power to circulate to and from the battery  24 . At the conclusion of the drive cycle, when the powertrain  10  is not operating, the contactors  56  will be opened to disconnect the battery  24  from high voltage components. 
         [0041]    In one non-limiting embodiment, the powertrain  10  may employ two contactors  56 , one of which is a pre-charge contactor. When commanded to close, the pre-charge contactor closes, then after a predefined charge is reached, the main contactor is closed and the pre-charge contactor opens during normal operation of the electrified vehicle  12 . In response to a vehicle key off condition, the contactors open to isolate the battery  24  from the high voltage bus  62 . 
         [0042]      FIG. 2  illustrates a vehicle system  64  that may be incorporated into an electrified vehicle, such as the electrified vehicle  12  of  FIG. 1 , in order to reduce start times of the electrified vehicle. The exemplary vehicle system  64  includes a contactor  56  that electrically connects and disconnects a battery  24  from an electric machine  66 . Although only a single contactor  56  is shown in  FIG. 2 , the vehicle system  64  could incorporate any number of contactors within the scope of this disclosure. In one non-limiting embodiment, the vehicle system  64  may close the contractor  56  when the electrified vehicle is off in order to improve vehicle start times. 
         [0043]    The vehicle system  64  may additionally include a sensor  68  and a control unit  70 . The sensor  68  is adapted to sense an early wake trigger  72 . For example, in one non-limiting embodiment, the sensor  68  may sense whether the vehicle operator or driver has applied a brake of the electrified vehicle. In another embodiment, the sensor  68  may detect whether a key has been positioned in an ignition of the electrified vehicle. Additional non-limiting examples of early wake triggers that can be monitored and detected by the sensor  68  include whether a vehicle door has been opened, whether a vehicle key is in relative proximity to the electrified vehicle, whether the electrified vehicle has been unlocked, whether a passenger has seated themselves in a seat of the vehicle, or any other early wake trigger. Generally, the early wake trigger  72  instructs the vehicle system  64  that a driver intends to start the electrified vehicle. Stated another way, the early wake trigger  72  occurs prior to starting the electrified vehicle or while the vehicle is in a key off condition. 
         [0044]    The control unit  70  may be part of a vehicle control system, such as the control system  58  of  FIG. 1 , or could alternatively be a stand-alone control unit. In one embodiment, the control unit  70  is adapted to close the contactor  56  in response to the early wake trigger  72 . For example, the sensor  68  may communicate an early wake signal  74  to the control unit  70  when the early wake trigger  72  is sensed. The control unit  70  may then communicate a command signal  51  to the contactor  56  that instructs the contactor  56  to close, such as by closing a relay switch or moving a movable contact into position relative to a stationary contact, thereby allowing high voltage current to flow over the high voltage bus  62  to power the electric machine  66 . 
         [0045]    In another embodiment, the control unit  70  may communicate another command signal S 2  to open the contactor  56  if a start request has not been received after a threshold amount of time has passed since the early wake trigger  72  was sensed. For example, by way of one non-limiting embodiment, the control unit  70  may communicate the command signal S 2  to open the contactor  56  if one minute has passed since the early wake trigger  72  and a driver has not attempted to start the electrified vehicle. 
         [0046]      FIG. 3 , with continued reference to  FIG. 1  and  FIG. 2 , schematically illustrates an exemplary startup sequence  99  of an electrified vehicle  12  that has been equipped with the vehicle system  64 . The exemplary startup sequence  99  may be performed to reduce the start times associated with the electrified vehicle  12 . 
         [0047]    The startup sequence  99  may begin in response to sensing an early wake trigger  72  at a time T 0 . Shortly thereafter, after various vehicle startup procedures and sequences have been initiated and performed, the control unit  70  may command the contactor  56  closed (closing indicated by a triangle in  FIG. 3 ) at a time T 1 . The time T 1  occurs before a vehicle start request  80  has been made. The vehicle start request  80  may occur at a time T 2 . 
         [0048]    The electrified vehicle  12  is considered ready to drive  82  at a time T 3 . The time T 3  can occur relatively soon after the vehicle start request  80  has been made by closing the contactor  56  at a period of time prior to starting the electrified vehicle  12  (i.e., at time T 1 ). In one non-limiting embodiment, as little as 66 milliseconds may pass between the times T 2  and T 3 . This is a relatively short amount of time compared to prior art vehicle systems which can require over 400 milliseconds between the times T 2  and T 3  to ready the electrified vehicle  12  for drive. 
         [0049]      FIG. 4  illustrates another exemplary vehicle system  164 . In this disclosure, like reference numbers designate like elements where appropriate and reference numerals with the addition of 100 or multiples thereof designate modified elements that are understood to incorporate the same features and benefits of the corresponding original elements. 
         [0050]    In this embodiment, the vehicle system  164  includes at least one contactor  156  that selectively connects and disconnects a battery  124  from an electric machine  166 . In one non-limiting embodiment, the vehicle system  164  may close the contractor  156  when the electrified vehicle is off in order to improve vehicle start times. 
         [0051]    A sensor  168  is adapted to sense an early wake trigger  172 . Generally, the early wake trigger  172  instructs the vehicle system  164  that a driver intends to start the electrified vehicle. The early wake trigger  172  occurs prior to starting the electrified vehicle or while the vehicle is in a key off condition. 
         [0052]    The vehicle system  164  of this embodiment includes a first control unit  170 - 1 , a second control unit  170 - 2 , and a third control unit  170 - 3 . In one non-limiting embodiment, the first control unit  170 - 1  is a body control module of the electrified vehicle, the second control unit  170 - 2  is a powertrain control module and the third control unit  170 - 3  is a battery electronic control module. Of course, the vehicle system  164  could include other controller arrangements. 
         [0053]    In one non-limiting control method, the sensor  168  may communicate an early wake signal  174  to the first control unit  170 - 1  upon sensing the early wake trigger  172 . The first control unit  170 - 1  may then communicate a wake-up signal S 1  to the second control unit  170 - 2 . Once awake, the second control unit  170 - 2  can communicate a command signal S 2  to the third control unit  170 - 3 . Once the third control unit  170 - 3  receives the command signal S 2 , it instructs the contactor  56  to close, via another command signal S 3 , to allow high voltage current to flow over a high voltage bus  162  to power the electric machine  166  or any other load. 
         [0054]    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. 
         [0055]    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. 
         [0056]    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.