Patent Publication Number: US-2021184286-A1

Title: Vehicle structural member with battery chiller

Description:
FIELD 
     The present disclosure relates to battery chillers, and particularly to battery chillers for vehicles. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Battery chillers are used in hybrid and electric vehicles to regulate the temperature of the vehicle batteries and thereby enhance vehicle performance. Such battery chillers are typically manufactured by brazing stamped aluminum or aluminum alloy plates together to form chambers for cooling fluid and refrigerant to flow through. For example, the stamped plates can have a dimple design that provides cavities for fluid to flow through and one chamber formed by a pair of adjacent stamped plates has cooling fluid that circulates and withdraws heat from the batteries and an adjacent chamber formed by a pair of adjacent stamped plates has refrigerant that withdraws heat from the cooling fluid. However, designs of such battery chillers are currently limited to brazing process capabilities and the shape and size of the dimples that can be stamped into the plates. 
     The present disclosure addresses the design issues of battery chillers, along with other issues related to manufacturing and packaging battery chillers in a vehicle. 
     SUMMARY 
     In one form of the present disclosure, a structural support member for a vehicle includes a structural member, a battery chiller disposed at least partially within the support member, and the battery chiller is additively manufactured at least partially within the support member. In some variations, the battery chiller includes a pair of spaced apart coolant chambers and a plurality of hollow pins extending between the pair of spaced apart coolant chambers such that the pair of spaced apart coolant chambers are in fluid communication with each other via the plurality of hollow pins. In such variations, a refrigerant chamber can be included and be between the pair of spaced apart coolant chambers such that coolant fluid flows from one of the pair of spaced apart coolant chambers to another of the pair of spaced apart coolant chambers through the refrigerant chamber via the plurality of hollow pins. In other such variations, a pair of spaced apart refrigerant chambers and another plurality of hollow pins extending between the pair of spaced apart refrigerant chambers can be included such that the pair of spaced apart refrigerant chambers are in fluid communication with each other via the another plurality of hollow pins. In at least one variation one of the pair of the spaced apart refrigerant chambers is between the pair of spaced apart coolant chambers and one of the pair of spaced apart coolant chambers is between the pair of spaced apart of refrigerant chambers. 
     In some variations, the battery chiller includes a stack of alternating coolant and refrigerant chambers with a plurality of hollow coolant pins extending between adjacent coolant chambers such that the adjacent coolant chambers are in fluid communication with each other via the plurality of hollow coolant pins and a plurality of hollow refrigerant pins extending between adjacent refrigerant chambers such that the adjacent refrigerant chambers are in fluid communication with each other via the plurality of hollow refrigerant pins. 
     In at least one variation the battery chiller is additively manufactured within a pre-existing structural member. In another variation the battery chiller and the structural member are formed together as an additive manufactured part. In such variations the structural member comprises a bottom wall and the battery chiller is additively manufactured onto the bottom wall. 
     In some variations, the structural member is a cross-member of a vehicle frame. 
     In another form of the present disclosure, a structural support member for a vehicle includes a vehicle structural member having a substructure and the substructure comprises an additive manufactured battery chiller. In some variations the battery chiller is additively manufactured within the vehicle structural member. In at least one variation the vehicle structural member includes a bottom wall and the battery chiller is additively manufactured on the bottom wall. 
     In some variations the battery chiller includes a top wall, a bottom wall, and a plurality of spaced apart intermediate walls between the top wall and the bottom wall. A plurality of hollow pins extend between the plurality of intermediate walls, and the plurality of spaced apart intermediate walls are in fluid communication with each other via the plurality of hollow pins. 
     In at least one variation, the battery chiller includes a plurality of coolant chambers and a plurality of hollow pins, the plurality of coolant chambers in fluid communication with each other via the plurality of hollow pins. In such a variation, the plurality of coolant chambers comprise a plurality of spaced apart walls with apertures, and the plurality of hollow pins are in fluid communication with the apertures from each of the plurality of spaced apart walls. 
     In still another form of the present disclosure, a structural support member for a vehicle is formed by a method including additive manufacturing a bottom wall, additive manufacturing a battery chiller on the bottom wall and additive manufacturing a structural member around the battery chiller such that the structural member includes the bottom wall. In some variations the battery chiller includes the bottom wall. In at least one variation the battery chiller includes a plurality of coolant chambers and a plurality of hollow pins, and the plurality of coolant chambers are in fluid communication with each other via the plurality of hollow pins. In such variations the plurality of coolant chambers include a plurality of spaced apart walls with apertures and the plurality of hollow pins are in fluid communication with the apertures from each of the plurality of walls. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a vehicle frame according to the teachings of the present disclosure; 
         FIG. 2  is a cross-sectional view of section A-A in  FIG. 1  showing a structural member and a battery chiller according to one form of the present disclosure; 
         FIG. 3  is a cross-sectional view of section A-A in  FIG. 1  showing a structural member and a battery chiller according to another form of the present disclosure; 
         FIG. 4  is a cross-sectional view of section A-A in  FIG. 1  showing a structural member and a battery chiller according to still another form of the present disclosure; 
         FIG. 5  schematically depicts a vehicle with a battery chiller according to the teachings of the present disclosure; and 
         FIG. 6  is a flow chart for a method of manufacturing a structural member and a battery chiller according to the teachings of the present disclosure. 
     
    
    
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     Referring to  FIG. 1 , a perspective view of a vehicle frame  10  according to the teachings of the present disclosure is shown. The vehicle frame  10  includes a plurality of structural support members  100 ,  110 ,  120 ,  130  (also referred to herein simply as “structural members”). In one form of the present disclosure, the plurality of structural members  100 ,  110 ,  120 ,  130  include a pair of main frame members  100  extending along a length direction (y direction) of the vehicle frame  10 , a plurality of cross-members  110  extending between the pair of main frame members  100 , a pair of front suspension members  120  extending from the pair of main frame members  100  along a length direction, and a plurality of brackets  130  attached to the pair of main frame members  100 , plurality of cross-members  110  and/or pair of front suspension members  120 . It should be understood that other structural members are included with a vehicle such as A-pillars, B-pillars, and door frames, among others, and such structural members are included within the teachings of the present disclosure. 
     Referring now to  FIG. 2 , a structural member of the vehicle frame includes a substructure  112  that comprises a battery chiller  200 . In the example shown in  FIG. 2 , the battery chiller  200  is positioned within one of the cross-members  110 . However, it should be understood that the cross-member  110  shown in  FIG. 2  can represent any of the structural members listed above, among others. The cross-member  110  includes a top wall  112  ( FIG. 1 ), a bottom wall  114 , and a pair of side walls  116  (only one side wall  116  shown in  FIG. 2 ). The battery chiller  200  has an enclosure  210  with a first coolant chamber  230  and a second coolant chamber  240  spaced apart from the first coolant chamber  230  (also referred to herein collectively as a “pair of spaced apart coolant chambers  230 ,  240 ”). 
     The enclosure  210  of the battery chiller  200  has a top wall  212 , a bottom wall  214 , a pair of end walls  216 , a pair of side walls (not shown but in the x-z plane in the figures), and a plurality of spaced apart intermediate walls  234 - 342  (described below) between the top wall  212  and the bottom wall  214 . In some variations of the present disclosure at least one of the pair of side walls of the battery chiller  200  is formed by one of the pair side walls  116  of the cross-member  110 . For example, in at least one variation the pair of side walls of the battery chiller  200  are formed by (i.e., are the same as) the pair side walls  116  of the cross-member  110 . In other variations, at least one of the pair of side walls of the battery chiller  200  is separate from an adjacent sidewall  116  of the cross-member  110 . Similarly, in some variations of the present disclosure, the bottom wall  214  of the battery chiller  200  is formed by the bottom wall  114  of the cross-member  110 , while in other variations, the bottom wall  214  of the battery chiller  200  is separate from the bottom wall  114  of the cross-member  110 . For example, and as discussed in greater detail below, in variations of the present disclosure the cross-member  110  (and other structural members disclosed herein) and the battery chiller  200  (and other battery chillers disclosed herein) are made by additive manufacturing (also known as “3D printing”) such that at least a portion of the battery chiller  200  is formed integral with the cross-member  110 . 
     The first coolant chamber  230  includes and is bounded by a top wall  232  and a bottom wall  234 , and the second coolant chamber  240  includes and is bounded by a top wall  242  and a bottom wall  244 . In some variations, the top wall  232  of the first coolant chamber  230  is formed by or is the same as the top wall  212  of the enclosure  210  and the bottom wall  244  of the second coolant chamber  240  is formed by or is the same as the bottom wall  214  of the enclosure  210 . In other variations, the top wall  232  of the first coolant chamber  230  is separate from the top wall  212  of the enclosure  210  and/or the bottom wall  244  of the second coolant chamber  240  is separate from the bottom wall  214  of the enclosure  210 . 
     Extending between the first coolant chamber  230  and the second coolant chamber  240  is a plurality of hollow pins  235  (also referred to herein as hollow coolant pins”). Each of the plurality of hollow pins  235  includes a first end  236  in fluid communication with the first coolant chamber  230  and a second end  237  in fluid communication with the second coolant chamber  240 . That is, the bottom wall  234  of the first coolant chamber  230  includes a plurality of first apertures  231 , the top wall  242  of the second coolant chamber  240  includes a plurality of second apertures (not shown), and the first end  236  of the plurality of hollow pins  235  is in fluid communication with the plurality of first apertures  231  and the second end  237  of the plurality of hollow pins  235  is in fluid communication with the plurality of second apertures. Accordingly, the plurality of hollow pins  235  provide fluid communication between the first coolant chamber  230  and the second coolant chamber  240  such that coolant  2  flowing through an inlet  220  into the first coolant chamber  230  flows through the plurality of hollow pins  235  and into the second coolant chamber  240 . Also, an outlet  222  is included with a bottom end  223  in fluid communication with the second coolant chamber  240  and a top end  224  providing fluid communication outside of the enclosure  210  such that coolant  2  flowing through the second coolant chamber  240  flows through the outlet  222  and exits the battery chiller  200 . 
     Still referring to  FIG. 2 , in some variations of the present disclosure a refrigerant chamber  250  is positioned between the pair of spaced apart coolant chambers  230 ,  240 . The refrigerant chamber  250  includes a top wall  252  and a bottom wall  254  which are in contact with the bottom wall  234  of the first coolant chamber  230  and the top wall  242  of the second coolant chamber  240 , respectively. In at least one variation the top wall  252  of the refrigerant chamber  250  and the bottom wall  234  of the first coolant chamber  230  are the same wall and/or the bottom wall  254  of the refrigerant chamber  250  and the top wall  242  of the second coolant chamber  240  are the same wall. A refrigerant inlet  251  and a refrigerant outlet  253  can be included such that refrigerant  3  enters the battery chiller  200  via the refrigerant inlet  251 , flows through the refrigerant chamber  250 , and exits the battery chiller  200  via the refrigerant outlet  253 . In the alternative, in at least one variation the inlet  220  and the outlet  222  are a double walled (not shown) such that coolant  2  flows in one direction (e.g., −z direction) through the inlet  220  and into the first coolant chamber  230  while refrigerant  3  flows from the refrigerant chamber  250  and exits the enclosure through the inlet  220  (not shown) in an opposite direction (e.g., +z direction). Similarly, coolant flows from the second coolant chamber  240  and through the outlet  222  in one direction (e.g., +z direction) and while refrigerant flows through the outlet  222  (not shown) in an opposite direction (−z direction) and into the refrigerant chamber  250 . It should be understood that other inlet and outlet configurations for entry and exit of the coolant  2  and/or refrigerant  3  can be used for the battery chiller  200  and are included in the teachings of the present disclosure. 
     While  FIG. 2  shows only one refrigerant chamber, it should be understood that more than one refrigerant chamber can be included. For example, and with reference to  FIG. 3 , the substructure  112  comprising a battery chiller  300  with a stack of alternating coolant chambers and alternating refrigerant chambers is shown. Particularly, the battery chiller  300  includes a first coolant chamber  330  spaced apart from a second coolant chamber  340 , and a first refrigerant chamber  350  spaced apart from a second refrigerant chamber  360  such that alternating coolant chambers and refrigerant chambers (along z direction in the figures) are provided. Similar to the battery chiller  200  ( FIG. 2 ), the battery chiller  300  is positioned within the cross-member  110  and the battery chiller  300  has an enclosure  310  with a top wall  312 , a bottom wall  314 , a pair of end walls  316 , a pair of side walls (not shown but in the x-z plane in the figures), and a plurality of spaced apart intermediate walls  334 - 362  (described below) between the top wall  312  and the bottom wall  314 . 
     In some variations of the present disclosure at least one of the pair of side walls of the battery chiller  300  is formed by one of the pair of side walls  116  of the cross-member  110 . For example, in at least one variation the pair of side walls of the battery chiller  300  are formed by (i.e., are the same as) the pair of side walls  116  of the cross-member  110 . In other variations, at least one of the pair of side walls of the battery chiller  300  is separate from an adjacent sidewall  116  of the cross-member  110 . Similarly, in some variations of the present disclosure, the bottom wall  314  of the battery chiller  300  is formed by the bottom wall  114  of the cross-member  110 , while in other variations, the bottom wall  314  of the battery chiller  300  is separate from the bottom wall  114  of the cross-member  110 . 
     The first coolant chamber  330  includes a top wall  332  and a bottom wall  334 , and the second coolant chamber  340  includes a top wall  342  and a bottom wall  344 . In some variations, the top wall  332  of the first coolant chamber  330  is formed by or is the same as the top wall  312  of the enclosure  310 , while in other variations the top wall  332  of the first coolant chamber  330  is separate from the top wall  312  of the enclosure  310 . 
     Extending between the first coolant chamber  330  and the second coolant chamber  340  is a plurality of hollow coolant pins  335 . Each of the plurality of hollow coolant pins  335  include a first end  336  in fluid communication with the first coolant chamber  330  and a second end  337  in fluid communication with the second coolant chamber  340 . Accordingly, the plurality of hollow pins  335  provide fluid communication between the first coolant chamber  330  and the second coolant chamber  340  such that coolant  2  flowing through an inlet  320  into the first coolant chamber  330  flows through the plurality of hollow pins  335  and into the second coolant chamber  340 . Also, an outlet  322  is included with a bottom end  323  in fluid communication with the second coolant chamber  340  and a top end  324  providing fluid communication outside of the enclosure  310  such that coolant  2  flowing through the second coolant chamber  340  can flow through the outlet  322  and exit the battery chiller  300 . 
     Still referring to  FIG. 3 , the first refrigerant chamber  350  is positioned between the first and second coolant chambers  330 ,  340  and the second refrigerant chamber  360  is positioned below (−z direction) the second coolant chamber  340 . The first refrigerant chamber  350  includes a top wall  352  and a bottom wall  354  which are in contact with the bottom wall  334  of the first coolant chamber  330  and the top wall  342  of the second coolant chamber  340 , respectively. In some variations of the present disclosure the top wall  352  of the refrigerant chamber  350  and the bottom wall  334  of the first coolant chamber  330  are the same wall and/or the bottom wall  354  of the first refrigerant chamber  350  and the top wall  342  of the second coolant chamber  340  are the same wall. 
     The second refrigerant chamber  360  includes a top wall  362  and a bottom wall  364  which are in contact with the bottom wall  344  of the second coolant chamber  340  and the bottom wall  314  of the enclosure  310 , respectively. In some variations of the present disclosure the top wall  362  of the second refrigerant chamber  360  and the bottom wall  344  of the second coolant chamber  340  are the same wall and/or the bottom wall  364  of the second refrigerant chamber  360  and the bottom wall  312  of enclosure  310  are the same wall. 
     Extending between the first refrigerant chamber  350  and the second refrigerant chamber  360  is a plurality of hollow refrigerant pins  355 . Each of the plurality of hollow refrigerant pins  355  include a first end  356  in fluid communication with the first refrigerant chamber  350  and a second end  357  in fluid communication with the second refrigerant chamber  360 . Accordingly, the plurality of hollow refrigerant pins  355  provide fluid communication between the first refrigerant chamber  350  and the second refrigerant chamber  360  such that refrigerant  3  flowing through an inlet  320  into the first refrigerant chamber  350  flows through the plurality of hollow pins  355  and into the second refrigerant chamber  360 . 
     A refrigerant inlet  351  and a refrigerant outlet  361  can be included such that refrigerant  3  flows enters the battery chiller  300  via the refrigerant inlet  351 , flows through the first refrigerant chamber  350 , the hollow refrigerant pins  355 , the second refrigerant chamber  360  and exits the battery chiller  300  via the refrigerant outlet  361 . In the alternative, in at least one variation the inlet  320  and the outlet  322  are a double walled (not shown) such that coolant  2  flows in one direction (e.g., −z direction) through the inlet  320  and into the first coolant chamber  330  while refrigerant  3  flows from the first and/or second refrigerant chambers  350 ,  360  and exits the enclosure  310  through the inlet  320  (not shown) in an opposite direction (e.g., +z direction). Similarly, coolant  2  flows from the second coolant chamber  340  and through the outlet  322  in one direction (e.g., +z direction) while refrigerant  3  flows through the outlet  322  (not shown) in an opposite direction (−z direction) and into the first and/or second refrigerant chambers  350 ,  360 . It should be understood that other inlet and outlet configurations for entry and exit of the coolant  2  and/or refrigerant  3  can be used with the battery chiller  300  and are included in the teachings of the present disclosure. 
     While  FIGS. 2 and 3  show a single battery chiller  200 ,  300  disposed at least partially within a structural member, it should be understood that a plurality of battery chillers can be disposed at least partially within a structural member. For example, and with reference to  FIG. 4 , the substructure  112  comprises a plurality of battery chillers  300  disposed within the cross-member  110  is shown. Also, in some variations, one or more of the battery chillers  300 , and other battery chillers disclosed herein, are included as a subunit that can be replaced as indicated in  FIG. 4 . For example, in some variations of the present disclosure, the battery chiller  300 , and other battery chillers disclosed herein, can include one or more brackets  317  that provide for the battery chillers  300  to be attached to each other such that an additional battery chiller  300  can be added and disposed within the cross-member  110  for enhanced cooling of vehicle batteries as shown in  FIG. 4 . And in other variations a battery chiller  300  can be removed from the cross-member  110  as shown in  FIG. 4 , e.g., to be replaced with another battery chiller  300 . 
     In operation, one or more battery chillers  300  are disposed within a structural member and a coolant inlet line (not shown) provides coolant  2  to the inlet  320 . The coolant  2  flows through the inlet  320  and into the first coolant chamber  330 . As shown in the  FIG. 3 , the coolant  2  flows from a left side (−x direction) towards a right side (+x direction) of the first coolant chamber  330 . Also, the coolant  2  flows from the first coolant chamber  330 , through the hollow coolant pins  335  and into the second coolant chamber  340  where it may or may not continue to flow from a left side (−x direction) towards a right side (+x direction) of the second coolant chamber  340 . In some variations of the present disclosure, the coolant exits the enclosure through the outlet  322  as indicated by the upward (+z direction) arrow positioned above the outlet  322 . 
     While coolant flows through the battery chiller  300  as described above, refrigerant  3  also flows through the battery chiller as shown in  FIG. 3 . Particularly, refrigerant  3  flows though the refrigerant inlet  351  and into the first refrigerant chamber  350  from a right side (+x direction) towards a left side (−x direction). Also, the refrigerant  3  flows through the hollow refrigerant pins  355  and into the second refrigerant chamber  360  where it may or may not continue to flow from the right side (+x direction) towards the left side (−x direction) of the second coolant chamber  340 . In some variations of the present disclosure, the refrigerant exits the enclosure through the refrigerant outlet  361  as indicated by the arrow positioned next to the outlet  361 . As shown in  FIG. 3 , in some variations of the present disclosure the refrigerant  3  flows in an opposite direction than coolant  2 . 
     Referring to  FIG. 5 , prior to flowing into the battery chiller  300  the coolant  2  is used to remove heat from vehicle batteries  400  and the refrigerant  3  is used to remove heat from the coolant  2  as it flows through the battery chiller  300 . That is, coolant  2  at a first temperature T 1  flows into the battery chiller  300  and while flowing through the first and second coolant chambers  330 ,  340  heat from the coolant  2  is transferred to the refrigerant  3  flowing through the first and second refrigerant chambers  350 ,  360 . Accordingly, coolant  2  exits the battery chiller  300  at a second temperature T 2  less than the first temperature T 1  (i.e., T 2 &lt;T 1 ) before being used again to remove heat from vehicle batteries  400 . Also, the refrigerant  3  flows through a refrigerant system  410  that removes heat from the refrigerant  3  after it exits the battery chiller  300  and before it re-enters the battery chiller  300  to be used again to remove heat from coolant  2 . 
     Referring now to  FIG. 6 , a method  50  of manufacturing a structural member with a battery chiller disposed at least partially within the structural member is shown. The method  50  includes uploaded or transferring a computer aided design (CAD) model of the structural member and/or battery chiller to an additive manufacturing machine at  500 . In some variations, the structural member is pre-existing (i.e., already formed) and has been formed with additive manufacturing or conventional manufacturing techniques as shown at  510 . In such variations a battery chiller is additively manufactured at least partially within the pre-existing structural member at  520  such that a structural member with a battery chiller disposed at least partially within the structural member is provided at  530 . For example, the structural member can be in the form of a U-shaped channel and the battery chiller is additively manufactured within the U-shaped channel using a bottom wall and/or side walls of the U-shaped channel as part of the battery chiller as described above with respect to battery chillers  200 ,  300 . 
     In other variations, the structural member is not pre-existing (i.e., it has not already been formed) and the structural member and the battery chiller are additively manufactured together at  540  such that an additively manufactured structural member with an additively manufactured battery chiller is provided at  550 . In such variations walls or surfaces of the structural member may or may not be the same as walls or surfaces of the battery chiller. For example, forming a bottom wall of the structural member may also be forming a bottom wall of the enclosure of the battery chiller and forming the side walls of the structural member may also be forming the side walls of the battery chiller. That is, the bottom wall of the structural member is the bottom wall of the enclosure and the side walls of the structural members are the side walls of the enclosure. 
     It should be understood that the teachings of the present disclosure include battery chillers that have a variety of shapes to fit within a given package design. For example, battery chillers with shapes such as a circular shape, a 90 degree bend shape and an oblong shape, among others, are provided. Also, the hollow pins allow coolant and/or refrigerant to flow between coolant and/or refrigerant chambers, respectively, for additional heat transfer, and the arrangement of the hollow pins are designed (e.g., staggered) to reduce pressure drop of a coolant and/or refrigerant flowing through a battery chiller. The hollow pins also provide enhanced strength such that reduced battery chiller size and durability are provided. In some variations the hollow pins can have a variation in height (z direction) such that variations in spacing between chambers is provided. And in at least one variation wall thicknesses for enhanced heat transfer and durability are additively manufactured as a function of component stresses observed from vehicle load data. In some variations of the present disclosure brackets and/or attachment points for the battery chillers are designed and additively manufactured into the battery chiller. 
     Non-limiting examples of additive manufacturing techniques for manufacturing the structural members with battery chillers disclosed herein include selective laser melting (SLM), direct metal laser sintering (DMLS) and electron beam melting (EBM), among others. Non-limiting examples of materials used to make the structural members with battery chillers disclosed herein include aluminum materials such as aluminum and aluminum alloys and copper materials such as copper and copper alloys, among others. In some variations of the present disclosure a structural member and a battery chiller disposed at least partially within the structural member are made from the same material (e.g., the same aluminum alloy), while in other variations a structural member and a battery chiller disposed at least partially within the structural member are made from different materials (e.g., different aluminum alloys). 
     It should also be understood that the teachings of the present disclosure provide a package friendly high performance battery chiller with reduced overall weight and enhanced durability and package flexibility. For example, additive manufactured battery chillers as disclosed herein can be manufactured into an existing structural member and thereby use or take up available space that is not currently being used. 
     Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice; material, manufacturing, and assembly tolerances; and testing capability. 
     As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.” 
     The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.