Abstract:
A transmission launch system includes a control system and a transmission having a plurality of clutches, where actuation of combinations of a predetermined number of clutches provides powerflow for different transmission drive gears. The control system is configured to initiate a performance launch of the vehicle where the transmission is commanded to engage a combination of the predetermined number of clutches corresponding to a forward drive gear. The transmission is then commanded to engage an additional clutch to lock its output shaft such that engine torque is prevented from being transferred to vehicle drive wheels. The engine generates drive torque greater than a capacity of a vehicle brake system and the control system then commands release of the additional clutch thereby unlocking the output shaft and allowing powerflow in the forward drive gear such that the generated engine drive torque is transferred to the drive wheels to propel the vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. Provisional Application Ser. No. 62/280,733 filed on Jan. 20, 2016. The disclosure of the above application is incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    The present application relates generally to vehicle transmissions and, more particularly, to an automatic transmission brake and method of using the same for improved vehicle staging and launch control and performance. 
       BACKGROUND 
       [0003]    In some vehicle launch scenarios, to increase performance of the vehicle at take-off, drivers sometimes perform a manual manipulation of the brakes and throttle to increase engine power and/or driveline torque immediately available to launch the vehicle. For example, the driver of the vehicle may apply the conventional vehicle foundation brakes while simultaneously increasing the throttle position to increase available engine and/or power to launch the vehicle. Such a methodology, however, requires the driver to simultaneously perform multiple tasks which may be difficult to safely or correctly perform, and is limited by the foundation brake system&#39;s ability to hold the vehicle stationary. Accordingly, it is desirable to provide an original equipment manufacturer integrated vehicle launch system with improved vehicle torque holding capability and performance. 
       SUMMARY 
       [0004]    In accordance with one example aspect of the invention, a vehicle transmission brake launch system is provided. In one exemplary implementation, the transmission brake launch system includes a transmission and a control system. The transmission includes a plurality of clutches and an output shaft, where actuation of different combinations of a predetermined number of clutches of the plurality of clutches provides powerflow for corresponding different transmission forward drive gears. The control system is configured to receive a command to initiate a performance launch of the vehicle; and command the transmission to engage a combination of the predetermined number of clutches corresponding to a predetermined forward gear. The transmission is commanded to engage an additional clutch of the plurality of clutches, thereby resulting in the transmission being in a state where the output shaft is bound and torque from the engine is prevented, by the transmission, from being transferred to drive wheels of the vehicle. The engine is commanded to generate drive torque, which is greater than a predetermined torque capacity of a foundation brake system of the vehicle; and, upon receipt of a command to launch the vehicle, the control system commands release of the additional clutch thereby unbinding the output shaft of the transmission and allowing powerflow in the predetermined forward gear such that the generated drive torque is transferred to the drive wheels to propel the vehicle. 
         [0005]    In one exemplary implementation, the control system is further configured to: confirm the foundation brakes are applied and vehicle brake torque is above a predetermined brake threshold; after commanding the transmission to engage the combination of the predetermined number of clutches corresponding to the predetermined forward gear and before commanding the transmission to engage the additional clutch, command the engine to generate a predetermined amount of torque that is less than the generated drive torque and less than the torque capacity of the foundation brake system; and transfer the predetermined amount of torque to the drive wheels through a driveline of the vehicle with the vehicle foundation brake system preventing movement of the drive wheels to thereby capture the predetermined amount of torque in the driveline to i) remove lash from the driveline, ii) preload bushings and shafts of the driveline, and iii) torque an axle of the driveline against associated travel limiters. 
         [0006]    In one exemplary implementation, the control system is further configured to: cause a message to be displayed via a user interface associated with an interior of the vehicle, the message instructing a brake pedal of the vehicle to be released; and maintain brake torque above the predetermined brake threshold independent of application of the brake pedal so as to keep driveline torque captured until the transmission is commanded to release the addition clutch. 
         [0007]    In one exemplary implementation, the plurality of clutches includes only five clutches, the transmission being free of any additional clutches utilized to make forward drive gears of the transmission. In one exemplary implementation, the combination of the predetermined number of clutches corresponding to the predetermined forward gear and the additional clutch are utilized in providing powerflow for first and second gears of the transmission. 
         [0008]    In one exemplary implementation, the combination of the predetermined number of clutches corresponding to the predetermined forward gear is utilized in providing powerflow for first gear of the transmission, and the additional clutch is utilized in providing powerflow for second gear and not for first gear. In one exemplary implementation, the combination of the predetermined number of clutches corresponding to the predetermined forward gear is utilized in providing powerflow for second gear of the transmission, and the additional clutch is utilized in providing powerflow for first gear and not for second gear. 
         [0009]    In one exemplary implementation, the combination of the predetermined number of clutches corresponding to the predetermined forward gear includes two brake clutches and one rotating clutch; and the additional clutch is a rotating clutch that, when utilized in the different combinations of the predetermined number of clutches of the plurality of clutches to provide powerflow for different forward drive speeds of the transmission, provides powerflow for second through fourth and sixth gears of the transmission. In one exemplary implementation, the additional clutch is a rotating clutch that, when utilized in the different combinations of the predetermined number of clutches of the plurality of clutches to provide powerflow for different forward drive speeds of the transmission, provides powerflow for first, third and fifth through seventh gears of the transmission. 
         [0010]    In one exemplary implementation, the control system is further configured to determine a tractive effort threshold where greater torque applied to the wheels would result in wheel slip and, based on this determined tractive effort threshold, command the predetermined forward gear to be first gear or second gear. 
         [0011]    Further areas of applicability of the teachings of the present disclosure will become apparent from the detailed description, claims and the drawings provided hereinafter, wherein like reference numerals refer to like features throughout the several views of the drawings. It should be understood that the detailed description, including disclosed embodiments and drawings references therein, are merely exemplary in nature intended for purposes of illustration only and are not intended to limit the scope of the present disclosure, its application or uses. Thus, variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]      FIG. 1  is graphical illustration of example vehicle launch control parameters for a vehicle foundation brake system and an exemplary transmission brake or “transbrake” arrangement in accordance with the principles of the present application; 
           [0013]      FIG. 2  is a schematic block diagram of an example vehicle system in accordance with the principles of the present application; 
           [0014]      FIG. 3  is a partial schematic illustration of an exemplary vehicle instrument panel and console of the vehicle system of  FIG. 1  in accordance with the principles of the present application; 
           [0015]      FIG. 4A  is a partial schematic illustration of an exemplary transmission of the vehicle system of  FIG. 1  in accordance with the principles of the present application; 
           [0016]      FIG. 4B  is a table illustrating exemplary clutch application and shift sequences for the transmission of the vehicle system of  FIG. 1  in accordance with the principles of the present application; 
           [0017]      FIG. 5A  is a schematic illustration of an exemplary transbrake application showing powerflow in connection with an exemplary transmission first gear vehicle launch in accordance with the principles of the present application; 
           [0018]      FIG. 5B  is a table illustrating exemplary clutch application and/or venting for the exemplary transbrake of  FIG. 5A  in accordance with the principles of the present application; 
           [0019]      FIG. 6A  is a schematic illustration of an exemplary transbrake application showing powerflow in connection with an exemplary transmission second gear vehicle launch in accordance with the principles of the present application; and 
           [0020]      FIG. 6B  is a table illustrating exemplary clutch application and/or venting for the exemplary transbrake of  FIG. 6A  in accordance with the principles of the present application. 
       
    
    
     DESCRIPTION 
       [0021]    In accordance with an example aspect of the invention and as will be discussed in greater detail herein, a transmission brake or transbrake system and associated methodology is provided and facilitates use of powertrain capability to hold a vehicle stationary and subsequently launch the vehicle with increased vehicle acceleration over a conventional vehicle launch. In one exemplary implementation, the transbrake provides for a strategic tie-up or locking of the vehicle automatic transmission to hold the vehicle stationary under a greater drive torque than can be withheld by a typical vehicle foundation brake system. 
         [0022]    During such an exemplary transmission tie-up, the engine throttle position may be increased, such as by the driver or ECU., while the vehicle (e.g., wheels, driveline, transmission) remain fixed/stationary because the transmission transbrake feature reacts all of the engine generated torque. When the transbrake is released, the vehicle will launch from a standstill at a high engine speed (RPM) and torque with maximum or substantially maximum torque converter multiplication. The increased engine torque and powertrain inertia generated by the transbrake are used to accelerate the vehicle at a greater rate than if transbrake was not utilized. In one exemplary implementation and as will also be discussed in greater detail below, the transbrake has three phases: Ready, Engaged and Release. The transbrake system and methodology may also be incorporated with a driveline protection strategy where driveline lash is removed or substantially removed prior to vehicle launch for protection and increased durability of the associated vehicle driveline components. 
         [0023]    In accordance with various aspects of the present disclosure, the transbrake system and methodology are implemented utilizing a vehicle system  10  of an exemplary vehicle  14  schematically illustrated in  FIG. 2 . The vehicle system  10  includes, in one exemplary implementation, an engine  18 , a transmission  22  coupled thereto, an associated driveline  26  and wheels  30 . The engine  18  and transmission  22  each include various respective sensors  32  and  34 , for sensing directly or indirectly parameters such as speed, pressure, temperature, position of clutch members or elements, etc., as is known in the art. Such sensors are in communication with and configured to provide signals to and receive signals or commands from each other and a vehicle control system (discussed below). 
         [0024]    The driveline  26  includes, in the exemplary implementation illustrated, a prop shaft  40  having associated bushings and joints  44 , axle(s) and/or halfshafts  48 , such as for front wheels and rear wheels, and snubber plates and/or other travel limiters  54 , as is known in the art. The vehicle system  10  also includes an electronic stability control system (ESC)  60 , a foundation brake system  64 , an instrument panel and/or console  68 , an accelerator pedal  72  and a brake pedal  134 . The foundation brake system includes an anti-lock braking system (ABS)  80  and one or more wheel speed sensors  84 , as is known in the art. The accelerator pedal  72  is for providing a driver input, e.g., a torque request, for engine  18 , as is also known in the art. 
         [0025]    In the exemplary implementation illustrated in  FIGS. 2 and 3 , the instrument panel  68  includes a driver/occupant/user interface  88  that includes various soft  92  and/or hard buttons  96  for providing input to the vehicle control system, as will be discussed below in greater detail. The driver interface  88  thus includes an interactive display screen  102  and/or cluster screen display  106  for providing/displaying information to the driver/occupants as well as for facilitating input (such as via the soft keys  92 ) to the vehicle control system, as is also known in the art. 
         [0026]    One or more controllers are utilized to control the various vehicle components or systems discussed above. In one exemplary implementation, various individual controllers are utilized to control the various components/systems discussed herein and are in communication with each other and/or the various components/systems via a main controller and/or local interface  110 . In this exemplary implementation, the local interface  110  is one or more buses or other wired or wireless connections, as is known in the art. In the example illustrated in  FIG. 2 , the local interface  110  is a controller area network (CAN). The CAN  110  may include additional elements or features, which have been omitted for simplicity, such as controllers, buffers (cache) drivers, repeaters and receivers, among many others, to enable communications. Further, the CAN  110  may include address, control and/or data connections to enable appropriate communications among the components/systems described herein and may also be referred to herein as the control system. 
         [0027]    In the example illustrated in  FIG. 2 , the vehicle system  10  includes an engine control unit (ECU)  118  for controlling engine  18  and a transmission control unit (TCU)  122  for controlling transmission  22 . Each of the control units ( 118 ,  122 ) as well as the ABS  80 , accelerator pedal  72 , instrument/console cluster  68 , paddle shifters  130  and brake pedal  134  are in communication with CAN  110  and thus each other. It will be appreciated that while individual control units are discussed herein and shown in various Figures, the individual control units may also be optionally implemented in the form of one control unit, such as a powertrain or vehicle control unit or system. Thus, it will be appreciated that while the discussion will generally continue with reference to the individual controllers discussed above, the discussion is equally applicable to the components of vehicle system  10  being controlled by one controller or vehicle control system. 
         [0028]    Referring briefly again to the conventional method for attempting to improve vehicle launch timing/acceleration discussed above, the vehicle driver applies the conventional vehicle foundation brakes  64  while simultaneously increasing the throttle position to increase available engine power to launch the vehicle. Such a methodology, however, is limited by the foundation brake system&#39;s  64  ability to hold the vehicle  14  stationary, which is significantly less than the transmission utilized with the transbrake system and method of the present application. 
         [0029]    For example and with reference to  FIG. 1 , the foundation brakes  64  for the vehicle of this example, are capable of holding the vehicle stationary up to only approximately 6,000 Nm of torque, whereas the transmission with use of the transbrake feature is configured to hold the vehicle stationary up to approximately 11,000 Nm of torque. Thus, the transbrake feature capitalizes on otherwise unused powertrain braking/locking capabilities to maintain the vehicle stationary while increasing engine  18  torque and/or speed to provide for improved and controlled vehicle  14  launch acceleration. In one exemplary implementation, the transbrake torque threshold triggering release of the transbrake is correlated to a vehicle wheel slip threshold, which is based at least on the vehicle weight and specific parameters of the vehicle tires (as well as road/track conditions). In one exemplary implementation, the wheel slip threshold is approximately 11,000 Nm and may be determined by the control system with or without input from the driver. 
         [0030]    As also briefly mentioned above, the transbrake feature involves a strategic automatic transmission tie-up or temporary locking to hold the vehicle stationary while the engine throttle position is increased. This provides an advantage of increased tractive effort to accelerate the vehicle upon release of the transbrake based on utilization of then stored powertrain energy. 
         [0031]    Below is a discussion of the transbrake feature in connection with use of clutches of transmission  22  to selectively lock transmission  22 ; followed by a discussion of exemplary control strategies and/or methodologies for implementing the transbrake feature in associated vehicle  14 . 
         [0032]    In one exemplary implementation and as will be discussed below by way of example with reference to an eight speed automatic transmission  22 , the transbrake feature is implemented while taking advantage of five existing controllable clutches (A-E) within the transmission  22 . In one exemplary implementation, the clutches (A-E) are electro-hydraulically controlled clutches, although one skilled in the art will appreciate that other controllable clutch or torque transfer device arrangements may be utilized in connection with the example eight speed transmission  22  or a transmission having more or less speeds. In one exemplary implementation, the transmission  22  includes only these five clutches (i.e., no additional clutches) for use in making forward drive gears. 
         [0033]    In this exemplary implementation, four clutches are utilized and/or controlled to temporarily tie-up or lock the transmission  22  such that an output or output shaft  126  of the same remains stationary. In this exemplary implementation and as can be initially seen in  FIGS. 4A-4B , a predetermined number of clutches, such as three clutches, are required to be activated/applied to make a gear, and a unique, selective application of a certain fourth clutch will selectively tie-up or lock the transmission  22  with the transbrake application, until the fourth clutch is released or deactivated, as explained in greater detail below.  FIG. 4A  illustrates a schematic layout of the exemplary eight-speed transmission  22 , which includes two stationary clutches or brakes A and B, and three rotating clutches C, D and E,  FIG. 4B  illustrates application of certain of the five clutches, as commanded by the TCU  122 , to make forward gears  1 - 8 , reverse gear and park. 
         [0034]    In one exemplary implementation and with particular reference to  FIGS. 5A-5B , one example application of transbrake will now be discussed in greater detail. In this exemplary application, clutches A, B and C are applied along with clutch E by command of the TCU  122  for the transbrake tie-up of the transmission  22 . With this application of four clutches, the transmission  22  is locked with no powerflow and the vehicle will remain stationary as the engine throttle position is increased by the driver and/or ECU in the manner discussed above. With application of clutches A, B and C, first gear is made, with powerflow shown by the dashed line  128 A in  FIG. 4A . As a result, when transbrake is applied with clutches A, B, C and E (see  FIGS. 5A and 5B ), additional clutch E is controlled to release or vent at a certain time, such as by TCU  122  in signal communication therewith, which will then result in the transmission  22  no longer being locked or tied-up and the configuration for first gear powerflow being in place. Therefore, upon release of clutch E, the vehicle  14  will launch in first gear. 
         [0035]    In another exemplary implementation and with reference to  FIGS. 6A-6B , clutches A, B and E are applied to make second gear in the transmission  22 , as shown by the powerflow dashed line  128 B in  FIG. 6A , and transbrake is applied or activated by TCU  122  applying or causing additional clutch C to be applied, as shown for example in  FIGS. 6B . As discussed above, application of four clutches in this manner creates the transbrake transmission tie-up, binding the output. Upon release or venting of clutch C, the vehicle  14  will launch in second gear (see powerflow  128 B in  FIG. 6A ), as the transmission  22  will no longer be locked and will be in the configuration for powerflow in second gear (i.e., application of clutches A, B and E). 
         [0036]    Select application and venting of the exemplary combination of clutches ABCE discussed above provides for the ability to selectively launch the vehicle  14  in either first or second gear, which can be determined automatically by the vehicle control system or in part or in full by the driver. Further, should the transbrake not hold the vehicle stationary, the vehicle will launch in a forward direction in either first or second gear. 
         [0037]    In another exemplary implementation, clutches A, B, C and D may be utilized for transbrake, as discussed below. In one implementation, clutches A, B and C along with clutch D are simultaneously applied for transbrake to tie-up the transmission, and then additional clutch D is vented or de-energized thereby leaving clutches A, B and C applied for powerflow in first gear. As can be seen with reference to  FIGS. 4A-4B , clutches A, B and D applied represent powerflow in Reverse. 
         [0038]    In another example implementation, clutches A, B, D and E may be simultaneously applied or caused to be applied by the control system  110  for the transbrake feature to tie up the transmission. Additional clutch D may then be vented or de-energized such that clutches A, B and E remain applied, which, as discussed above, is the configuration for powerflow in second gear. As a result, using transbrake in this manner will yield a second gear vehicle launch. 
         [0039]    As briefly mentioned above, the transbrake control and application strategy may be summarized as including three phases: Ready, Engage and Release. Each of these phases will be discussed below in connection with overall operation and use of the transbrake system to launch an associated vehicle, such as exemplary vehicle  14 . 
         [0040]    In one exemplary implementation, in order to activate transbrake, a vehicle user, such as the driver, activates a track or drag racing or equivalent vehicle mode, such as by selecting a representative icon or button (e.g., soft button  92 ) using the driver/user interface  88 . Upon accessing the drag or similar vehicle mode or page via the soft buttons  92  of the driver interface  88 , for example, the driver indicates the intent to activate transbrake by simultaneously applying and holding for a predetermined period of time, steering wheel mounted left and right paddles  130  ( FIG. 3 ). In one exemplary implementation, the vehicle system  10  then evaluates various vehicle and powertrain conditions/parameters before allowing entry to the transbrake Ready Phase. 
         [0041]    In one exemplary implementation, the entrance criteria for the Ready phase includes: the vehicle  14  being in drag or an equivalent mode as discussed above; application of the left and right paddle shifters  130  as also discussed above; vehicle brake pressure/torque being above a predetermined threshold; engine speed being above a predetermined threshold; front wheels  30  being orientated in a forward direction and/or within a predetermined tolerance of the same; transmission  22  temperature between a minimum and maximum threshold; vehicle speed being zero; and the transmission  22  being placed in a predetermined gear. 
         [0042]    If the entrance criteria are met, the Ready phase is entered. In one exemplary implementation, a communication indicative of the same is presented to the driver, such as via the infotainment unit user interface  88  or interface  106 . In the Ready phase, a predetermined minimal amount of forward drive torque is sent through the vehicle driveline  26  and captured by the vehicle foundation brake system  64  (which is applied by the driver as indicated by the minimum brake pressure/torque threshold criteria discussed above). This provides for preloading the driveline  26  with forward drive torque to remove all lash from the driveline. In one exemplary implementation, driveline bushings  44  and shaft(s)  40  are preloaded and an associated axle/halfshafts  48  is/are wound up against snubber plates or other anti-rotation features and/or travel limiters  54 . In this exemplary implementation, a predetermined amount of torque is commanded to be provided by the engine  18  and transferred to the drive wheels  30  via the transmission  22  and driveline  26 , where this predetermined amount of torque is less than the torque that will subsequently be generated by the engine  18  for launching the vehicle  14  with transbrake, and is less than a torque capacity of the foundation brake system  64 . 
         [0043]    Next is the Engaged phase. To enter this phase, and upon completion of the above in connection with the Ready phase, the vehicle operator will release one of the shifter paddles or other hard or soft buttons serving  130  for this function. The vehicle controller or control system  110  will verify or continue to verify that the criteria discussed above in connection with entering the Ready phase is still met or true with the exception of both paddle shifters  130  being applied. If such conditions are still met and the operator has released one of the paddle shifters  130  while maintaining application of the other paddle shifter  130 , the transbrake feature will be applied. 
         [0044]    During the Engaged phase or phase  2 , an electronic stability control (ESC) or similar system  60  of the vehicle  14  holds or maintains the previously applied or applied brake pressure to keep or maintain the captured driveline torque or preload. The driver can now release the brake pedal  134  as the ESC system  60  will maintain the brake pressure and hold the vehicle  14  stationary. The transmission controller  122  will then apply transbrake by applying a fourth clutch element (additional clutch) to tie-up or lock the transmission (noting that the transmission  22  is already in a gear, such as first gear, as discussed above). For example, the transmission controller  122  will ultimately apply four clutches (e.g., A, B, C and E) for first or second gear launch as discussed above. 
         [0045]    At this point, the control system  110  will cause a message to be displayed in the instrument panel  68 , such is in the user display screen  102  of the infotainment unit  88  or  106 , indicating that transbrake is engaged or activated or the like. In one exemplary implementation, the messaging is communicated over the vehicle CAN BUS and/or a local private network. While in the Engaged phase, the driver or ECU can increase the throttle position to increase engine torque to launch the vehicle  14 . As discussed above, this engine  18  torque is reacted by the transbrake transmission  22  feature thereby allowing downstream powertrain components and the vehicle  14  to remain stationary until transbrake is released. In one exemplary implementation, the engine  18  torque is reacted solely by the transbrake transmission tie-up and is much greater than the torque capacity of the foundation brake system  64 . 
         [0046]    In one exemplary implementation, the vehicle control system, such as the transmission controller, can limit the engine RPM to a predetermined threshold while in the Engaged phase. This threshold can be based on, for example, one or more of the following: torque threshold capability of locked transmission; tire slip threshold; predicted tractive effort threshold depending on road/track surface and tire parameters. 
         [0047]    With regard to the second and third thresholds, the vehicle control system would include information on the weight of the vehicle and request, if not available, input on the wheel speed vs. ground speed and/or tire parameters and road or track surface conditions (e.g., temperature, moisture amount, etc.). With this information, the vehicle control system will utilize an on-board algorithm or, via an internet connection associated with the infotainment unit or the like, communicate with an external system to determine a tractive effort threshold. 
         [0048]    This determined tractive effort threshold can, in one exemplary implementation, be communicated to the driver via the user interface  88 . Additionally or alternatively, the driver can be requested to enter a desired torque threshold for launch and the vehicle control system  110  can confirm or indicate the requested threshold is not available as it is above the determined tractive effort threshold. This provides the vehicle operator the ability to tune the available tractive effort while having the vehicle control system predict/simulate that the same is within predetermined or determined threshold(s) based on vehicle components and road/track surface conditions. Additionally, the operator can be presented with an option for a first or second gear launch depending on, for example, the determined tractive effort thresholds and the amount of engine  18  torque requested by the driver or ECU. 
         [0049]    To enter the Release phase, which includes releasing the transbrake to accelerate the vehicle  14  from the standstill, the vehicle control system will verify that one or more of the criteria discussed with respect to entrance to the Engaged phase remain true. To release the transbrake, the operator will release the remaining applied or actuated paddle shifter  130 . Upon the vehicle control system  110  receiving an indication of the same and the exit criteria (discussed immediately above) confirmed to remain true or acceptable, launch of the vehicle  14  will occur with release or venting of the fourth/additional clutch element. 
         [0050]    More specifically, for the ABCE clutch application transbrake strategy, first gear launch will occur when additional clutch E is released, or second gear launch will occur when additional clutch C is released. For the ABCD clutch application transbrake strategy, first gear launch will occur when additional clutch D is released. And, for the ABDE clutch application transbrake strategy, second gear launch occurs when additional clutch D is released. 
         [0051]    As discussed above, transbrake makes use of available vehicle components to react engine torque and provide significantly greater tractive effort torque for launch of the vehicle as compared to use of the vehicle&#39;s foundation brakes. Transbrake provides an OEM integrated approach with various safety and durability protecting features, as well as tunability options for the driver. Further, with respect to the transmission, transbrake does not require, in an exemplary implementation, any additional transmission hardware and utilizes a unique strategy discovered to temporarily lock the transmission and then release the same in a predetermined first or second gear launch powerflow configuration. 
         [0052]    It will be understood that the mixing and matching of features, elements, methodologies and/or functions between various examples may be expressly contemplated herein so that one skilled in the art would appreciate from the present teachings that features, elements and/or functions of one example may be incorporated into another example as appropriate, unless described otherwise above.