Patent Publication Number: US-2017358418-A1

Title: Fuse array for vehicle electrical system having multiple discrete circuits

Description:
FIELD 
     The present invention relates generally to a fusible component for a vehicle electrical system and, more particularly, to a fuse array with multiple discrete circuits for a vehicle electrical system having multiple batteries, such as those used in start-stop vehicles. 
     BACKGROUND 
     Conventional fuse arrays for vehicle electrical system components, such as fuse array  120  illustrated in  FIG. 9 , typically have a single discrete circuit for current to flow through. Battery power, or B+ power as it is also known, is provided to the fuse array  120  by a low voltage battery (not shown) via battery power terminal  122 . Current associated with the B+ power flows within a conductive bus bar  124  and then branches out via individual fuses (not shown), which are separately connected to a junction box terminal  128  and several high current terminals  130 . The junction box terminal  128  connects the fuse array  120  to a bus bar  140 , which in turn is connected to a downstream component in the form of a junction box (not shown). The high current terminals  130  connect the fuse array  120  to various high current devices in the vehicle electrical system. Skilled artisans will appreciate that the current paths within the fuse array  120  are protected from current surges by the different individual fuses, but that the fuse array only has a single discrete circuit. 
     Some vehicles, like certain start-stop vehicles, have two separate batteries where each battery separately provides B+ power to the vehicle electrical system. For multiple battery applications like this, it may be desirable to provide a single fuse array that includes multiple discrete circuits so that B+ power can be provided from both batteries to the components of choice through a single fusible component. 
     SUMMARY 
     According to one aspect, there is provided a fuse array for use in a vehicle electrical system having first and second vehicle batteries. The fuse array may comprise: an insulative housing; a first discrete circuit for providing battery power from the first vehicle battery to a first downstream component, the first discrete circuit includes a first internal bus bar secured on the outside of the insulative housing and a first fuse contained within the insulative housing; and a second discrete circuit for providing battery power from the second vehicle battery to a second downstream component, the second discrete circuit includes a second internal bus bar secured to the outside of the insulative housing. The first and second discrete circuits are electrically isolated from one another within the fuse array so that the first discrete circuit can provide battery power from the first vehicle battery to the first downstream component and the second discrete circuit can independently provide battery power from the second vehicle battery to the second downstream component. 
    
    
     
       DRAWINGS 
       Preferred exemplary embodiments of the invention will hereinafter be described in conjunction with the appended drawings, wherein like designations denote like elements, and wherein: 
         FIG. 1  is a perspective view of an exemplary power distribution device, in this case a power distribution center (PDC), that includes an exemplary embodiment of a fuse array; 
         FIGS. 2 and 3  are perspective views of the fuse array of  FIG. 1 , where the fuse array is shown connected to a bus bar within the power distribution device; 
         FIG. 4  is a plan view of the fuse array of  FIGS. 2 and 3 ; 
         FIG. 5  is an exploded perspective view of the fuse array of  FIGS. 2 and 3 ; 
         FIG. 6  is a perspective view of a bus bar that is part of the fuse array of  FIGS. 2 and 3 ; 
         FIG. 7  is a perspective view of an additional bus bar that is part of the fuse array of  FIGS. 2 and 3 ; 
         FIG. 8  is a schematic view of the fuse array of  FIGS. 2 and 3 , where current flow through the fuse array has been illustrated to show the multiple discrete circuits within the fuse array; and 
         FIG. 9  is a perspective view of a conventional fuse array that has only a single discrete circuit. 
     
    
    
     DESCRIPTION 
     The fuse array described herein is a fusible component with multiple discrete circuits and is designed for use in a vehicle electrical system having more than one battery. The fuse array may be incorporated within or used in conjunction with any number of different vehicle electrical system components, such as a pre-fuse assembly or a power distribution device like a power distribution center (PDC), a vehicle electrical center (VEC), a power distribution box (PDB), an electrical connection box, a junction box assembly, etc. 
     According to one non-limiting example, the fuse array described herein is connected to a power distribution device that is part of a ‘start-stop vehicle’ that automatically shuts off the internal combustion engine when the vehicle comes to a stop and automatically restarts the engine when the driver starts driving again (e.g., when the driver lifts off of a brake pedal or engages a clutch pedal). By shutting off the engine while the vehicle is idling and resuming only when the driver is ready to start driving, the start-stop vehicle is able to improve fuel economy and decrease emissions. Some start-stop vehicles employ two batteries: a first low voltage battery (e.g., a 12 v lead-acid or other battery for starting the engine and providing power to certain accessories), and a second low voltage battery (e.g., a 12 v lithium-ion battery for storing regenerative braking charge and assisting with power and load management). The fuse array described herein provides multiple discrete circuits within a single assembly, where a first discrete circuit can connect the first low voltage battery to downstream components and a second discrete circuit can connect the second low voltage battery to different downstream components. 
     It should be appreciated that while the fuse array is not limited to use with start-stop vehicles and may be used in a number of other applications, the multiple discrete circuits of the present fuse array make it particularly well suited for systems having multiple batteries, like those sometimes employed by start-stop vehicles, electric vehicles or hybrid electric vehicles, to cite a few possibilities. The fuse array of the present invention is not limited to the examples described herein, as they are simply provided to illustrate different potential embodiments and features of the fuse array. 
     Beginning with  FIG. 1 , there is shown a non-limiting example of a power distribution device  10  for a vehicle, in this case a power distribution center (PDC), connected to a fuse array  30 . Those skilled in the art will appreciate that the power distribution device  10  may provide for compact and efficient power distribution within a vehicle&#39;s electrical system, including power distribution for lower and higher amperage components. As shown in  FIG. 1 , the fuse array  30  is physically and electrically connected to a bus bar  32  which is part of the power distribution device  10  so that power may be provided from a first battery (not shown), through the fuse array  30 , and to the power distribution device  10  via bus bar  32 . Other arrangements are certainly possible. 
     Turning now to  FIGS. 2 and 3 , there are shown several enlarged perspective views of the fuse array  30 , where the fuse array is still connected to the separate bus bar  32  that is part of the power distribution device  10 . The fuse array  30  is a fusible component that protects certain downstream electrical devices within the vehicle electrical system from current surges and, according to this example, includes a first battery terminal  34 , a first internal bus bar  36 , a set of first fuses  38 , a set of first output terminals  40  (components  34 - 40  constitute a first discrete circuit  56 ), a second battery terminal  44 , a second internal bus bar  46 , a second output terminal  50  (components  44 - 50  constitute a second discrete circuit  58 ), and an insulative housing  52 . The first discrete circuit  56  receives B+ power from a first vehicle battery through the first battery terminal  34  and then distributes that power via the first internal bus bar  36 , the set of first fuses  38 , and the set of first output terminals  40 . Whereas the second discrete circuit  58  receives B+ power from a second vehicle battery through the second battery terminal  44  and conveys that power via the second internal bus bar  46  and the second output terminal  50 . 
     These two circuits  56 ,  58  are discrete and electrically isolated from one another, despite the fact that they both flow through the same fuse array  30 . According to the embodiment described below, the first discrete circuit includes four different branches or current paths, each of which includes a different output terminal  40  that provides a different downstream component with B+ power. Thus, the first discrete circuit  56  is connected to a common battery and is at a common shared voltage, but may include a plurality of individual branches or current paths connected to different downstream components. According to that same embodiment, the second discrete circuit  58  only has one output terminal and, thus, only includes one branch or current path. In the example where the second discrete circuit  58  is connected to the power distribution center (PDC)  10  that has its own fuses, relays, etc., the second discrete circuit would not need to be fused itself (this explains why only the first discrete circuit  56  in the preceding embodiment includes a set of fuses). It is possible for discrete circuits  56 ,  58  to be at the same voltage (e.g., they could both be part of 12 v or 42 v systems) or they could be at different voltages (e.g., circuit  56  could be part of a 12 v system while circuit  58  is part of a 42 v system). Other examples are also possible. 
     First battery terminal  34  is an input terminal that is connected to a first vehicle battery and corresponding battery cable (not shown) so as to provide battery power or B+ power to the fuse array  30 , and it is bolted down on the fuse array using a terminal stud  64  and terminal nut  66 . As best illustrated in  FIG. 3 , the first battery terminal  34  may include a cable retaining feature  70  at one end that crimps around and retains a terminal end of the battery cable and a fuse relay mounting feature  72  at the other end that wraps around and fits over top of a portion of the first internal bus bar  36 . Those skilled in the art will appreciate that there are a number of potential battery terminal designs and configurations and that the first battery terminal  34  is not limited to the exemplary one shown in  FIGS. 2 and 3 , as that is just one possibility. 
     First internal bus bar  36  conveys and/or distributes B+ power within the first discrete circuit  56  and, according to one embodiment, provides for several different branches or current paths. According to the embodiment best shown in  FIG. 6 , the first internal bus bar  36  is made of a conductive metal, such as copper or a copper alloy, and includes a terminal side  80  (top horizontal side in  FIG. 6 ), an opposing base side  82  (bottom horizontal side) and a connecting side  84  (back vertical side) that connects the terminal and base sides together. When viewed from the side, the first internal bus bar  36  has a somewhat C-shaped configuration. It is apparent from the drawings that the first internal bus bar  36  has an open slot  100  towards the middle of the bus bar so as to accommodate the second internal bus bar  46 , as will be explained in more detail. 
     Terminal side  80 , according to one embodiment, is a top horizontal side of the first internal bus bar  36 . The terminal side includes a number of separate terminal connection portions  86 ,  88 , where terminal connection portion  86  is configured to receive the first battery terminal  34 , terminal connection portions  88  are designed to receive the set of first output terminals  40 , and the open slot  100  has no terminal connection portion. Because of their similarity, only the terminal connection portion  86  is described below with the understanding that the description generally applies to the other terminal connection portions  88  as well. Each of the terminal connection portions  86 ,  88  has a hole or opening  90  that is sized and shaped to receive a terminal stud  64  so that the stud can be secured with a corresponding terminal nut  66 , as previously explained. Because the terminal side  80  has thin slots or spaces  94  separating the different terminal connection portions  86 ,  88  from one another, electrical current cannot pass directly from one terminal connection portion to the next. This slotted arrangement helps form the different branches or current paths mentioned above, as will be subsequently described in more detail. At a distal end of each of the terminal connection portions  86 ,  88 , there is a turned flange  96  that is bent at approximately 90° so as to extend downwards towards the opposing base side  82 . The size and configuration of the terminal connection portions  86 ,  88 , including the turned flanges, are designed to help the first internal bus bar  36  fit around and grasp the insulative housing  52 . 
     Base side  82  is a bottom side of the first internal bus bar  36  and, according to the illustrated embodiment, spans the entire length of the bus bar. The base side  82  includes a number of turned flanges  110 , which like their counterparts that extend from the upper terminal side  80 , are bent at approximately 90° and are designed to help grasp and maintain the insulative housing  52  within the first internal bus bar. In order to better accommodate the second internal bus bar  46 , the turned flange that would normally oppose the terminal connection portion  86  may be removed, as seen with the missing flange  102  in  FIG. 6 . This is not required, but it may be useful in providing better clearance for the different components of the fuse array. 
     Connecting side  84  acts as a side wall for the first internal bus bar  36  and physically and electrically connects the terminal side  80  to the base side  82 . Like the terminal or top side  82 , the connecting side  84  includes a number of individually slotted side connection portions  126 ,  128  that are separated from one another by thin slots or spaces  120  that extend in the vertical direction. Again, this separated or slotted arrangement helps facilitate the individual current branches or paths that are part of the first discrete circuit  56 . Side connection portion  126  is physically connected to terminal connection portion  86  and helps provide B+ power to the rest of the internal bus bar  36 , whereas side connection portions  128  are physically connected to terminal connection portions  88  and help establish the different current paths. As is clearly illustrated in  FIG. 6 , the open slot  100  that accommodates the second internal bus bar  46  creates an opening or void in the connecting side  84 . This arrangement and its purpose will become more apparent as the fuse array is further explained. 
     First set of fuses  38  are designed to protect downstream electrical components from current surges, such as those that could damage an alternator or a radiator fan, and are part of the first discrete circuit  56 . Skilled artisans will appreciate that a number of different types of fusible components could be used with the first set of fuses  38 . According to an exemplary embodiment, the first set of fuses  38  includes several individual fusible links, one for each of the different current branches within the first discrete circuit. As best illustrated in  FIG. 5 , the insulative housing  52  includes several different chambers or compartments and inside of each chamber is a fusible link that is part of a different current path. For example, a first current path that provides an alternator with B+ power would have a first fusible link designed to handle suitable current for an alternator (e.g., 40 amps), and a second current path that powers a radiator fan would have a second fusible link designed to handle typical radiator fan amperage (e.g., 30 amps). The preceding examples of high amperage devices are merely intended to illustrate the concept of providing a first set of fuses  38  with specifically selected fusible links based on the downstream components that they are intended to protect; the present invention is not limited to such examples. 
     First set of output terminals  40  connect to various downstream electrical components in order to provide them with B+ power. Referring back to  FIG. 3 , there are shown four separate output terminals  40  which are somewhat similar in design to the first battery terminal  34  described above. Each of the output terminals  40  includes a cable retaining feature and a fuse relay mounting feature and is secured to the first internal bus bar  36  using a terminal stud and nut; because of their similarity with features  64 ,  66 ,  70 ,  72  described above, which share the same names, the previous description applies here as well. 
     According to the present embodiment, the first battery terminal  34 , the first internal bus bar  36 , the set of first fuses  38 , and the set of first output terminals  40  constitute the first discrete circuit  56 . Within that discrete circuit, there are four separate branches or current paths, one for each of four downstream electrical components that require B+ power. The description now turns to the second discrete circuit  58 , which is electrically isolated from the first discrete circuit  56  and is designed to separately power a downstream component like a power distribution box (not shown). 
     Second battery terminal  44  is very similar to the first battery terminal  34 , except that it connects a battery cable from a second vehicle battery (not shown) to the second internal bus bar  46 . The B+ power provided by the second vehicle battery may be at the same voltage or a different voltage from that supplied by the first battery. 
     Second internal bus bar  46  may distribute power within the fuse array, similar to the first internal bus bar  36 , but it is much smaller and different in configuration. With reference to  FIG. 7 , the second internal bus bar  46  may be made of copper or a copper-based alloy and includes a terminal connection portion  130 , an intermediary portion  132 , and an output connection portion  134 . In the particular embodiment shown in the figures, the second internal bus bar  46  is part of the second discrete circuit  58 , which connects to a power distribution box or some other electrical distribution device that has its own fuses, relays, etc.; thus, the second discrete circuit does not need to be fused, which explains why bus bar  46  directly connects B+ power to the separate bus bar  32  without first passing through a fusible component. Of course, it is possible for the second discrete circuit  58  to have a fusible component. 
     Terminal connection portion  130  fits over top of the insulative housing  52  and includes a hole or opening  140  for receiving a terminal stud and nut  142 ,  144  ( FIG. 2 ), and it includes a turned flange  146  that is generally bent downwards so as to engage and latch onto the housing  52  when the fuse array is assembled. An illustration of an assembled fuse array is shown in  FIG. 4 , where it can be seen that the second internal bus bar  46  is installed on the insulative housing  52  in the open slot  100 . 
     Intermediary portion  132  joins portions  130  and  134  together and, according to one embodiment, is simply a bent side portion with a locking portion  150  in the form of an opening or window. The locking portion  150  is sized and shaped to receive some type of tang or tab on the insulative housing  52  so that the bus bar  46  and housing  52  can be mechanically secured to one another. The locking portion  150  is optional, however, as other means for securing these components together could be used instead. 
     Output connection portion  134  connects the second discrete circuit  58  to a downstream component, like bus bar  32  of a power distribution box, and may be configured in any number of suitable ways. For instance, the illustrated embodiment shows the output connection portion  134  having a hole or opening  154  for receiving the second output terminal  50  (e.g. a threaded stud and nut). Other embodiments are certainly possible. 
     Operation of the fuse array  30  is described in conjunction with the drawing in  FIG. 8 , which schematically illustrates the two discrete circuits  56 ,  58 . Beginning with the first discrete circuit  56 , B+ power is provided from a first vehicle battery, through the first battery terminal  34 , and throughout the different current branches or paths in the first bus bar  36 . As the battery power distributes in the various current branches, current flows through each of the fuses  38 , out through the output terminals  40 , and to the different high amperage downstream components, like an alternator or radiator fan. In this way, each current branch within the first discrete circuit  56  is individually or separately fused to protect against a current surge, even though all of the current branches are part of the same discrete circuit and are maintained at the same voltage. Turning now to the second discrete circuit  58 , B+ power is provided from the second vehicle battery to the second battery terminal  44 , from the second battery terminal to the second internal bus bar  46 , and from the second internal bus bar to the output terminal  50 , which may be connected to a power distribution box or the like. As explained above, power distribution devices oftentimes have their own collection of fuses, relays, etc., which explains why the current path within the second discrete circuit  58  is not independently fused or otherwise protected from current surges. 
     It is to be understood that the foregoing is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims. 
     As used in this specification and claims, the terms “for example,” “e.g.,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.