Abstract:
A catcher bracket disposed between a powertrain and a sub-frame of a vehicle. The catcher bracket defines a load path in a collision that is sufficient to displace the powertrain that directs the force of the impact through the catcher bracket to a sub-frame of the vehicle. The sub-frame is connected to the body structure of the vehicle by fasteners that fracture to decouple the powertrain and sub-frame from the body structure of the vehicle to reduce the collision pulse.

Description:
TECHNICAL FIELD 
     This disclosure relates to an apparatus that reduces the extent of intrusion into the passenger compartment of a hybrid electric vehicle by decoupling a sub-frame from a body structure of a vehicle in a collision that causes the displacement of a powertrain. 
     BACKGROUND 
     Hybrid electric vehicles include both electric and gasoline powertrains for providing traction for the vehicle. Hybrid electric vehicles require added space for the dual (electric motor/combustion engine) powertrain that reduces the space available for absorbing energy in a collision. The dual powertrain including the transmission and battery increase the mass of the powertrain of the hybrid electric vehicle and increases the kinetic energy exerted by the powertrain upon the vehicle body and passenger compartment. Increased kinetic energy may be transferred to the passenger compartment and may result in an increased extent of intrusion into the passenger compartment. 
     Vehicle pulse is a term that is used to describe the deceleration function of a vehicle. Increasing vehicle pulse increases the peak severity of the impact and reduces the performance of the vehicle in crash tests. The reduced space available in hybrid electric vehicles and increased weight of hybrid electric vehicle powertrains both tend to reduce increase the deceleration pulse in a collision. 
     This disclosure is directed to solving the above problems and other problems as summarized below. 
     SUMMARY 
     This disclosure describes a catcher bracket for an engine/transmission powertrain of a hybrid electric vehicle. The vehicle may be a Full Hybrid Electric Vehicle (“FHEV”) or a Partial Hybrid Electric Vehicle (“PHEV”). The powertrain and body structure of the vehicle may be decoupled from the body structure of the vehicle in the event of a collision. Decoupling the powertrain from the body structure is accomplished by providing a powertrain catcher bracket that allows the engine cradle sub-frame to decouple from the body structure. Decoupling reduces intrusions into the passenger compartment, particularly in the area of the dash panel/toe board. The powertrain is spaced from but is oriented to contact the catcher bracket in a collision. The catcher bracket is driven downwardly and rearward by the force of the collision causing the sub-frame to become decoupled from the body and slide below the passenger compartment. 
     According to one aspect of this disclosure, a catcher bracket disposed between a powertrain and a sub-frame of a vehicle comprises a tubular body and at least one fastener. The tubular body has an engagement end on a front portion that has an impact surface that is spaced from and faces the powertrain and an attachment end opposite the engagement end on a rear portion. The at least one fastener secures the attachment end of the tubular body to the sub-frame. 
     According to other aspects of this disclosure, the tubular body may have a top wall, a right side wall, and a left side wall that form a box-shaped enclosure extending between the engagement end and the attachment end and that defines an open bottom. The catcher bracket may further comprise a right side flange extending outwardly from the right side wall and a left side flange extending outwardly from the left side wall. The impact surface may further comprise an end wall that is provided at the engagement end that encloses the engagement end and provides a planar surface that is oriented to face a contact surface on the powertrain. The end wall may be joined on a right edge to the right side wall and may be joined on a left edge to the left side wall. 
     According to other aspects of this disclosure, the sub-frame may be a clam shell structure including an upper panel and a lower panel. The attachment end may include an upper flange that is attached to the upper panel and at least one lower flange that is attached to the lower panel. The at least one lower flange may further comprise a right flange and a left flange that are each connected to the lower panel. The tubular body may have a top wall, a right side wall and a left side wall that form a rectangular enclosure extending between the engagement end and the attachment end. A right side flange extends outwardly from the right side wall and a left side flange extends outwardly from the left side wall. A first fastener connects the right side flange to the sub-frame and a second fastener connects the left side flange to the sub-frame. A top wall flange extends rearward from the top wall and a third fastener connects the top wall flange to the sub-frame. 
     The sub-frame may be attached to a body structure of the vehicle by sub-frame attachment brackets and at least one fastener. The sub-frame is loaded through the tubular body during a collision that detaches the powertrain from the vehicle and that causes the powertrain to shift into engagement with the engagement end of the tubular body. The sub-frame may be detached from the body structure of the vehicle by fracturing the at least one fastener. 
     According to another aspect of this disclosure, a collision pulse reduction assembly is provided for a vehicle having a powertrain. The assembly includes a bumper beam and an energy absorbing crush element disposed between the bumper beam and the powertrain. A sub-frame disposed between the powertrain and a body structure of the vehicle is attached to the body structure by at least one fastener. A powertrain catcher bracket is disposed rearward of the powertrain and attached to the sub-frame. The assembly provides a load path for reducing a pulse of deceleration of the vehicle in a collision. The bumper beam receives an impact that is transferred in sequence to the crush element, then the powertrain, then the catcher bracket, then the sub-frame, and then the at least one fastener that causes the at least one fastener to fracture. The sub-frame is detached from the body structure when the fastener fractures. 
     According to other aspects of this disclosure regarding the collision pulse reduction assembly, the powertrain catcher bracket is spaced from the powertrain in an “as assembled” position and is engaged by the powertrain in a collision of sufficient severity to displace the powertrain from a powertrain mounting apparatus. 
     The catcher bracket may have a top wall, a right side wall and a left side wall that form a box-shaped enclosure extending between an engagement end and an attachment end and defining an open bottom. The collision pulse reduction assembly may further comprise a right side flange extending outwardly from the right side wall and a left side flange extending outwardly from the left side wall. An end wall may be provided at the engagement end that encloses the engagement end and provides a planar surface that is oriented to face a contact surface on the powertrain. The end wall is joined on a right edge to the right side wall and is joined on a left edge to the left side wall. 
     According to other aspects of this disclosure regarding the collision pulse reduction assembly, the sub-frame may be a clam shell structure including an upper panel and a lower panel and the powertrain catcher may include an upper flange that is attached to the upper panel and at least one lower flange that is attached to the lower panel. The at least one lower flange may further comprise a right flange and a left flange that are each connected to the lower panel. The powertrain catcher bracket may have a top wall, a right side wall and a left side wall that form a rectangular enclosure defining an open bottom. A right side flange may extend outwardly from the right side wall and a left side flange may extend outwardly from the left side wall. A first fastener may connect the right side flange to the sub-frame and a second fastener may connect the left side flange to the sub-frame. A top wall flange may extend rearward from the top wall and a third fastener may be used to connect the top wall flange to the sub-frame. 
     The sub-frame may be attached to a body structure of the vehicle by at least one sub-frame attachment bracket and at least one fastener. The powertrain may engage the powertrain catcher during a collision that detaches the powertrain from the vehicle. The powertrain catcher loads and detaches the sub-frame from the body structure of the vehicle by fracturing the at least one fastener. 
     The above aspects of this disclosure and other aspects will be described in greater detail below with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a fragmentary bottom plan view of a front end of a vehicle that is provided with a powertrain catcher bracket. 
         FIG. 2  is a perspective view of a powertrain catcher bracket attached to a sub-frame. 
         FIG. 3  is a top plan view of a powertrain catcher bracket attached to a sub-frame. 
         FIG. 4  is a front/right perspective view of a powertrain catcher bracket. 
         FIG. 5  is a top plan view of the powertrain catcher bracket. 
         FIG. 6  is a diagrammatic side view of the front end of a vehicle prior to a collision in an “as assembled” condition. 
         FIG. 7  is a diagrammatic side view of the front end of a vehicle having a powertrain catcher bracket showing the powertrain engaging the powertrain catcher bracket as a result of the collision. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of the illustrated embodiments of the present invention is provided below. The disclosed embodiments are examples of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed in this application are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art how to practice the invention. 
     Referring to  FIG. 1 , a vehicle  10  is partially illustrated to show the front end  12  from below the vehicle. A catcher bracket  16 , or tubular body, is attached to a sub-frame  18  of the vehicle. A lower panel  20  of the sub-frame  18  is visible in  FIG. 1 . 
     A powertrain is generally indicated by reference numeral  22 . The powertrain  22  includes a combustion engine  24  and may also include an electric motor if the vehicle is a FHEV or a PHEV. The electric motor of the hybrid vehicle is not illustrated. The powertrain  22  also includes a transmission  26  that provides torque from the combustion engine  22 , or electric motor (not shown), to the wheels  28  of the vehicle  10 . 
     Sub-frame attachment brackets  30  connect the sub-frame  18  to the vehicle  10 . Fasteners  32  are used to secure the sub-frame  18  to the vehicle  10 . 
     Referring to  FIGS. 2 and 3 , the catcher bracket  16  is shown attached to the sub-frame  18 . An upper panel  34  of the sub-frame  18  is visible in  FIGS. 2 and 3 . The upper panel  34  and lower panel  20  of the sub-frame  18  are welded together in a clamshell manner to form the sub-frame  18 . The fasteners  32  that are used to connect the sub-frame  18  to the vehicle  10  are shown installed on the sub-frame  18 . 
     Referring to  FIGS. 4 and 5 , the structure of the catcher bracket  16  is shown in isolation. An engagement end wall  36  that is a planar surface is provided in a front portion  38  of the catcher bracket  16 . The engagement end wall  36  provides an impact surface  40 . The function of the impact surface  40  will be described with reference to  FIG. 6  below. At the opposite end of the catcher bracket  16 , an attachment end  42  is provided at a rear portion  44  of the catcher bracket  16 . 
     The catcher bracket includes a top wall  48 , a right sidewall  50  and a left sidewall  52 . The catcher bracket  16  has an open bottom  54  that is defined by the right sidewall  50 , left sidewall  52  and the engagement end wall  36 . A right side flange  56  extends laterally outward from the right sidewall  50 . A left side flange  58  extends laterally outward from the left sidewall  52 . A right edge  62  of the engagement end wall  36  is welded to the right sidewall  50 . A left edge  64  of the engagement end wall  36  is welded to the left sidewall  52 . 
     An upper flange  66  extends in a rearward direction from the top wall  48 . A lower flange  68  extends rearward from the right side flange  56  and the left side flange  58 , respectively. An opening  70  is provided in the upper flange  66  and an opening  72  is provided in each of the lower flanges  68 . A bolt  76  is inserted through the opening  70  in the upper flange  66  that connects the catcher bracket  16  to the sub-frame  18 . A pair of bolts  78  are assembled into the opening  72  in the lower flanges  68 . 
     Referring to  FIGS. 6 and 7 , a collision sequence is illustrated. Impact arrow A depicts the direction of the initial impact in a front end collision. In a front end collision, a bumper beam  80  is initially contacted and driven in a rearward direction against crush elements  82 , or crush cans, that absorb some of the energy of the impact. In a collision that is of sufficient severity to fully compress the bumper  80  and crush cans  82 , the impact continues to displace the powertrain  22  from its “as assembled” position shown in  FIG. 6  and into engagement with the catcher bracket  16 , as shown in  FIG. 7 . The arrow L in  FIG. 7  illustrates the direction of displacement of the powertrain  22  as it is driven into engagement with the catcher bracket  16 . The location of the impact is illustrated by the impact star I in  FIG. 7 . The force of the impact is transferred from the powertrain  22  to the catcher bracket  16 . 
     The powertrain  22 , as shown in  FIG. 6 , is spaced from the catcher bracket  16 . An engagement surface  84  on the powertrain  22  is arranged in a generally parallel and spaced relationship relative to the impact surface  40  of the catcher bracket  16 . The force of the impact is transferred from the catcher bracket  16  to the sub-frame  18 . Forces applied to the sub-frame  18  cause the fasteners  32  connecting the sub-frame  18  to a body structure  86 , or body-in-white. The force applied to the sub-frame  18  fractures the fasteners  32  allowing the powertrain  22  and sub-frame  18  to be decoupled from the body-in-white  86 . 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosed apparatus and method. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure as claimed. The features of various implementing embodiments may be combined to form further embodiments of the disclosed concepts.