Patent Document

FIELD OF THE INVENTION  
       [0001]     The present invention relates to electrical and mechanical connectors that provide evidence of tampering, and in particular to electrical and mechanical connectors for automobile engine heat exchangers.  
       BACKGROUND OF THE INVENTION  
       [0002]     In the motor vehicle field, it is known that interchangeable parts are often used, wherein different variants of a component may have the same mounting provisions. While this of course has advantages in terms of cost efficiency, it can also raise an issue with regard to product functionality and regulatory compliance. Specifically, where a variant of a part performs a function not shared by the original components, installing the incorrect part may have adverse consequences on one or more functions of the vehicle.  
         [0003]     This can be an issue in the case of vehicle components that play a role in improving air quality. For example, some radiator assemblies for motor vehicles are known to include a coating of a catalytic material for converting environmentally harmful substances in ambient air during the utilization of the motor vehicle. The purpose of this catalytic coating is to improve the environment by cleaning ambient air as the vehicle is driven. Such a coated radiator assembly is likely to have the same mounting provisions as similar uncoated radiator assemblies that do not convert the environmentally harmful substances in ambient air. Because a coated radiator can cost more than an uncoated one, vehicles built with uncoated radiators could be sold in some jurisdictions. Further, uncoated radiators will certainly be made available for aftermarket installation as spare parts in such jurisdictions.  
         [0004]     Where a particular market requires an air-cleaning radiator or gives emission “credits” for such a radiator, that market is also likely to require that evidence and/or assurance be provided that the proper, coated radiator, as opposed to an uncoated radiator without the air-cleaning function, is installed on the vehicle. For example, in California all cars must have on board diagnostics (OBD) that function at all times. Original equipment manufacturers (OEMs) are required to warrant these diagnostics for up to fifteen years or 150,000 miles. In order to ensure compliance with California regulatory and environmental standards, OEMs must be able to provide some assurance that the OBD system has not been tampered with through most of the useful life of a vehicle.  
         [0005]     It is thus a primary object of the present invention to provide a system and method for determining whether certain OEM hardware has been altered. Moreover, it is an object of the present invention to provide a tamper-evident sensor and method that itself is immune to tampering, thus providing twofold assurance to the OEMs, consumers and government regulators that the motor vehicle is in compliance with the applicable guidelines and laws.  
       SUMMARY OF THE INVENTION  
       [0006]     Accordingly, the present provides a sensor and a method of utilizing the sensor that provides evidence of tampering therewith.  
         [0007]     One embodiment of the present invention concerns a method for attaching a sensor to a body such that subsequent removal of the sensor from the body provides evidence, either mechanical and/or electrical, that the sensor has been removed. In another embodiment of the present invention, there is a sensor assembly that is attached to opposite sides of a body. Assembly of the sensor onto the body establishes a path of electrical continuity which is broken if the sensor is removed from the body. In another embodiment of the present invention, a sensor case and sensor attachment clip are coupled together through a passageway of a body. The sensor case and attachment clip are coupled in such a way that removal of the sensor case from the attachment clip causes damage to the case or the clip.  
         [0008]     These and other aspects, embodiments, and features of the present invention will be apparent from the description of the preferred embodiment, the drawings and the claims to follow. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a schematic representation of a system according to one embodiment of the present invention.  
         [0010]      FIG. 2   a  is a top plan view of a sensor assembly according to one embodiment of the present invention.  
         [0011]      FIG. 2   b  is a side elevational view of the sensor assembly of  FIG. 2   a.    
         [0012]      FIG. 2   c  is an end elevational view of the sensor assembly of  FIG. 2   a.    
         [0013]      FIG. 2   d  is a perspective view of the sensor assembly of  FIG. 2   a.    
         [0014]      FIG. 3  is a sectional view of the sensor assembly of  FIG. 2   a  as taken along line  3 - 3  of  FIG. 2   a.    
         [0015]      FIG. 4  is a bottom plan view of a circuit board assembly in accordance with the present invention.  
         [0016]      FIG. 5  is an exploded perspective view of the sensor assembly of  FIG. 2   a.    
         [0017]      FIG. 6  is a perspective view of the sensor assembly of  FIG. 2   a  with the case body removed.  
         [0018]      FIG. 7  is an exploded view of the sensor assembly of  FIG. 2   a  positioned to be inserted into a portion of a heat exchanger.  
         [0019]      FIG. 8  is a perspective view of the sensor assembly of  FIG. 2   a  assembled onto a portion of a heat exchanger.  
         [0020]      FIG. 9   a  is a side elevational view of the sensor assembly of  FIG. 2   a  properly disposed about a heat exchanger in a first orientation.  
         [0021]      FIG. 9   b  is a side elevational view of the sensor assembly of  FIG. 2   a  disposed about a heat exchanger in a second orientation such that evidence of tampering is recognized.  
         [0022]      FIG. 10  is a perspective view of the sensor assembly of  FIG. 2   a  assembled onto a portion of a heat exchanger.  
         [0023]      FIG. 11  is a side elevational view of a sensor assembly according to another embodiment of the present invention.  
         [0024]      FIG. 12  is a bottom plan view of a portion of the sensor assembly of  FIG. 11 .  
         [0025]      FIG. 13  is a cross sectional view of the apparatus of  FIG. 11  as taken along line  13 - 13  of  FIG. 12 .  
         [0026]      FIG. 14  is a perspective view of the apparatus of  FIG. 11 .  
         [0027]      FIG. 15  is a perspective view of the sensor assembly of  FIG. 10  assembled onto a portion of a heat exchanger.  
         [0028]      FIG. 16  is an end perspective view of a portion of the apparatus of  FIG. 10 .  
         [0029]      FIG. 17  is an end plan view of the apparatus of  FIG. 16 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0030]     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.  
         [0031]     The present invention relates to a sensor assembly that is attached to an object such that any attempt to remove the sensor from the object is not only difficult, but results in the production of evidence of the attempted removal. In one embodiment, the sensor assembly is provided in two separate parts that are attached together in a manner that also attaches the two parts to the object. The two parts are coupled together by a projection received in a “one way” locking manner. The projection cannot be pulled out of the receptacle without permanent deformation to one or both parts of the sensor.  
         [0032]     In yet another embodiment of the present invention, the two parts are coupled together in a manner that simultaneously attaches the two parts to the object. When the two parts are coupled together, a circuit path is created. The circuit path can be monitored to determine whether or not the path is continuous. If the two parts of the sensor are separated from one another, electrical continuity is lost and evidence of tampering is provided to the vehicle&#39;s control system.  
         [0033]     In yet another embodiment of the present invention, a sensor is provided in two separate parts. The -separate parts are attached to each other simultaneously with their attachment to an object. The two parts are mechanically coupled together with a locking mechanism. Neither of the two separate parts is provided with any feature that allows external access to the locking mechanism. Therefore, any attempt to remove the attached sensor would require drilling of access holes or the like in order to reach the locking mechanism.  
         [0034]     In a preferred embodiment, the sensor is provided in two separate parts that are mounted to opposing sides of an automotive radiator. The automotive radiator has one or more external surfaces that have been coated with a catalyst that promotes a chemical reaction in ambient ozone to produce oxygen. Operation of a vehicle with such a radiator cleans any ambient air by removing some of the ozone. Such a vehicle is qualified under federal law to be claimed within a pollution credit. However, the law also requires some manner of ensuring that the pollution-removing device has not been tampered with. Further discussion of catalyst-coated heat exchangers can be found in U.S. Pat. No. 6,695,473, issued Feb. 24, 2004; U.S. Pat. No. 6,506,605, issued Jan. 14, 2003; and U.S. Pat. No. 6,681,619, issued Jan. 27, 2004; all of which are incorporated herein by reference.  
         [0035]     A preferred embodiment of the present invention provides both mechanical and electrical evidence of any potential tampering with the vehicle system. For example, if someone attempted to install a non-coated radiator into the vehicle, such a non-complying radiator would not be provided with an embodiment of the tamper-evident sensor and the installer of the radiator would be aware of the non-compliance based on the lack of the sensor. In addition, an electronic controller of the vehicle would recognize that the tamper-evident sensor has not been installed, and would set an appropriate output flag. Further, it would be difficult to attach a sensor removed from a coated radiator to the non-coated radiator. The attachment would be difficult because removal of the sensor results in physical deformation of the sensor and/or breakage of the electrical circuit formed by installation of the sensor.  
         [0036]      FIG. 1  is a schematic representation of a system  20  according to one embodiment of the present invention. System  20  includes an internal combustion engine  22  that is cooled by a heat exchanger  24 , such as an automotive radiator. System  20  further includes a sensor assembly  30  preferably attached to heat exchanger  24  in a manner that makes removal of the sensor difficult. Further, the attachment of sensor assembly  30  is preferably accomplished in a manner whereby removal of sensor assembly  30  leaves mechanical evidence and/or electronic evidence of tampering. In one embodiment, sensor assembly  30  is in electrical communication with a signal processor  26  that acquires one or more signals from sensor assembly  30 , and preferably provides indication if sensor assembly  30  is removed from heat exchanger  24 . In one embodiment, signal processor  26  is a digital computer that performs other functions for engine  22 , which can include control functions.  
         [0037]     Although in one embodiment, sensor assembly  30  is attached to an automotive radiator, the present invention is not so limited. In other embodiments of the present invention, the sensor assembly can be attached to an automotive air conditioner heat exchanger, an automotive oil heat exchanger, an industrial-use heat exchanger, a residential air conditioner heat exchanger, or the like. In yet other embodiments, sensor assembly  30  is attached to any object having a passageway in which it is desirable to know whether or not the sensor has been removed from that object. As another example, the sensor assembly could be a sensor integrated into a home security system and attached to a wall.  
         [0038]     Referring to  FIGS. 2-6 , sensor assembly  30  includes a sensor case  32  with one or more lead wires  34  extending from it and taking one or more signals to signal processor  26 , and an attachment member clip assembly  50 . Attachment member clip assembly  50  includes one or more projections  54  which are received within one or more receptacles  56  of sensor case  32 . Sensor assembly  30  further includes a circuit board  40 . 1  contained within sensor case  32 .  
         [0039]     Referring to  FIGS. 3-6 , sensor case  32  includes a circuit board or first sensor  40 . 1  mounted within a sensor case body  36  and sensor case cover  37 . Referring to  FIG. 3 , a sensor case cover  37  mates with case body  36  and supports circuit board  40 . 1  securely therein. Preferably, case cover  37  is ultrasonically bonded to case body  36 . Case cover  37  defines the entryways to a plurality of receptacles  56 . 1 ,  56 . 2 ,  56 . 3 , and  56 . 4 , which are adapted and configured to receive a corresponding projection  54 . 1 ,  54 . 2 ,  54 . 3 ,  54 . 4 , respectively. An electrical connector  38  provides signals from circuit board  40 . 1  to lead wires  34 . Electrical connector  38  may be of any type, including direct connection of lead wires  34  to circuit board  40 . 1 , or connection of lead wires  34  to circuit board  40 . 1  by a pair of mating male and female connectors. A plurality of sensor cooling fins  44  is integrally molded into case body  36 .  
         [0040]     In one embodiment, sensor case  32  also includes at least two thermistors  40 . 2 ,  40 . 3  disposed on the circuit board  40 . 1  and in communication with the lead wires  34  to signal processor  26 . As shown in  FIGS. 3 and 4 , the first thermistor  40 . 2  and second thermistor  40 . 3  are disposed on the bottom side of the circuit board  40 . 1 . The thermistors  40 . 2 ,  40 . 3  are adapted for sensing a temperature, such as that generated by the operation of a motor vehicle heat exchanger  24 . As noted, the thermistors  40 . 2 ,  40 . 3  are in electrical communication with the signal processor  26  via a fixed disposition on the circuit board  40 . 1 . As such, the orientation of the circuit board  40 . 1  relative to the heat source will affect the temperatures detected by the thermistors  40 . 2 ,  40 . 3 , which will allow the signal processor  26  to determine how the circuit board  40 . 1  and sensor case  32  are oriented. The significance of the orientation of the sensor case  32  is discussed in detail below.  
         [0041]     As best seen in  FIGS. 5 and 6 , right and left circuit board clips  42 . 1  and  42 . 2 , respectively, attach circuit board  40 . 1  within sensor case  32 , and are coupled both mechanically and electrically to circuit board  40 . 1  by a plurality of contacts  64 . 1 ,  64 . 2 ,  64 . 3 , and  64 . 4 . Preferably, circuit board clips  42  are electrically conductive and in electrical communication with circuit board  40 .  1 , although the present invention contemplates embodiments in which the circuit board clips are non-conductive and a continuity circuit is established to the projections  54  by a plurality of lead wires from circuit board  40 . 1 .  
         [0042]     Each circuit board clip  42  includes a plurality of projection retaining springs  60 . 11 ,  60 . 12 ,  60 . 21 ,  60 . 22 ,  60 . 31 ,  60 . 32 ,  60 . 41 , and  60 . 42 . Each of these projection-retaining springs  60  are of a cantilever spring-type. Retaining springs  60  are biased outwardly toward the exterior of sensor case  32 . Each projection  54  includes a spring clip  58  located near the free end of the projection. Projection spring clips  58  are offset inwardly toward the interior of sensor case  32 .  
         [0043]     As best seen in  FIG. 6 , complete insertion of a projection  54  within the corresponding receptacle  56  results in an inward compression of a pair of corresponding cantilever springs  60 , which snap outwardly into place in contact with a ledge near the free end of a projection spring clip  58 . For an example, and still referring to  FIG. 6 , projection  54 . 3  is shown completely inserted within receptacle  56 . 3 . Retaining springs  60 . 31  and  60 . 32  are in compression with a side surface of projection  54 . 3 . Further, projecting ledges near the ends of retaining springs  60 . 31  and  60 . 32  are in contact with the ledge  59 . 3  of projection  54 . 3 . Insertion of a projection within a receptacle results in sliding of a projection spring clip  58  over the corresponding projection retaining springs  60 , with one or both spring clip  58  and retaining springs  60  snapping back into place upon complete insertion of the projection, with the protruding ledges of the projection retaining springs  60  being locked into an interference with the opposing ledges  59  of the corresponding projection  54 . Attachment member clip assembly  50  includes an attachment member body  52  with a shape adapted and configured for interfacing with a contact surface of the heat exchanger or other object.  
         [0044]     As best seen in  FIG. 3 , in one embodiment, attachment member body  52  is generally planar to match the planar surface of an automatic heat exchanger. The plurality of projections  54  extends from body  52 . In one embodiment, projections  54  are fabricated from a material that is a good conductor of heat, such as aluminum. Attachment member body  52  also includes a resilient pad  80 . 2  such as a PORONO pad, or a silicone rubber pad, bonded to the interior surface of body  52 . Case cover  37  preferably also includes a resilient pad  80 . 1 , such as a PORONO pad or a silicone rubber pad, bonded to one surface of case body  37 . Although the use of resilient pads  80 . 1  and  80 . 2  have been shown and described, the present invention further contemplates any material or mechanism which provides a compressible surface to one or both of the opposing surfaces of sensor case  32  and attachment member clip assembly  50 . When the projections  54  of the attachment member clip assembly  50  are fully inserted and locked into place within corresponding receptacles  56 , the resilient pads  80 . 1  and  80 . 2  are compressed. Because of their resiliency, these pads attempt to force apart attachment member assembly  50  from sensor case  32 . The resilient pads, or other compressible surfaces, urge the sensor case  32  and attachment lever clip  50  apart so as to produce a state of tension in one or more projections  54 .  
         [0045]     In one embodiment, attachment clip  50  includes four projections  54 . 1 ,  54 . 2 ,  54 . 3 , and  54 . 4 , each of which is received within a corresponding receptacle  56 . 1 ,  56 . 2 ,  56 . 3 , and  56 . 4 , respectively, when sensor assembly  30  is mounted to an object. As best seen in  FIGS. 2   b  and  2   d,  the insertion and locking of the projections into the receptacles establishes a predetermined distance  48  between the opposing surfaces  33  of the sensor case and  53  of the attachment member. Although an attachment member clip assembly  50  having four projections has been shown and described, the present invention contemplates other arrangements. For example, in one embodiment of the present invention there is a single projection that extends from the attachment member clip assembly to the sensor case. Further, although an arrangement of projections  54  has been shown and described in a rectangular array, the present invention contemplates other arrangements including, for example, a triangular arrangement of three projections. As another example, the present invention contemplates those embodiments in which the attachment member clip assembly includes both a projection and a receptacle, and the sensor case also includes a projection and a receptacle. In this embodiment, the receptacle of the attachment member would receive the projection of the sensor case, and the receptacle of the sensor case would receive the projection of the attachment member.  
         [0046]     As best seen in  FIG. 6 , circuit board clip contacts  64 . 1 ,  64 . 2 ,  64 . 3 , and  64 . 4  are mechanically connected to circuit board  40 . 1 , and further are in electrical communication with circuit board  40 . 1 . Further, these board clip contacts  64  are in electrical communication with pairs of retaining springs  60 . For example, board clip contact  64 . 1  and  64 . 2  are in electrical communication with retaining springs  60 . 1  land  60 . 12 , and  60 . 21  and  60 . 22 , respectively. Likewise, board clip contact  64 . 3  is in electrical communication with retaining springs  60 . 31  and  60 . 32 ; board clip contact  64 . 4  is in electrical communication with retaining springs  60 . 41  and  60 . 42 . Further, pairs of retaining springs  60  are in electrical communication with the electrically conductive projections  54 . As one example, retaining springs  60 . 11  and  60 . 12  are in electrical communication with projection  54 . 1 . Likewise, each of the other three projections is in electrical communication with a corresponding pair of retaining springs.  
         [0047]     Referring to  FIG. 7 , attachment member body  52  and projections  54  are preferably electrically conductive. In one embodiment, projections  54 . 1  and  54 . 2  located on one side of clip assembly  50  are in joint electrical communication with body  52 . Further, projections  54   3  and  54 . 4  are in joint electrical communication with body  52 . Therefore, pathways of electrical continuity are established from circuit board  40 . 1  into contacts  64 .  1  and  64 . 2 , through circuit board clip  42 . 1 , through the retaining springs  60  to the corresponding first pair of projections  54 . 1  and  54 . 2 . Continuity from these projections through attachment member body  52  is established to the projections  54 . 3  and  54 . 2 , likewise through the corresponding retaining springs  60  into circuit board clip  42 . 2 , into contacts  64 . 3  and  64 . 4 , and back to circuit board  40 . 1 . Therefore, sensor assembly  30  includes a pathway of electrical continuity from one side of circuit board  40 . 1 , through the attachment member clip assembly  50  to the other side of circuit board  40 . 1 .  
         [0048]     The presence of electrical continuity in the circuit can be monitored through lead wires  34  by signal processor  26 . By monitoring this continuity circuit, it is possible for signal processor  26  to indicate if attachment member clip assembly  50  has been removed from sensor case  32 . If this happens, such as the case where a user removes sensor assembly  30  from heat exchanger  24 , signal processor  26  detects and indicates the loss of continuity. Therefore, the continuity circuit established by the assembly of sensor case  32  and attachment member clip assembly  50  is a means for providing evidence of tampering.  
         [0049]     Although what has been shown and described is a use of a continuity circuit as means for providing evidence of tampering, the present invention contemplates other methods as well. For example, by the use of four circuit board clips instead of two circuit board clips, two separate paths of continuity could be established among the four projections. Further, the present invention contemplates those embodiments having a single projection, in which continuity could be established by an electrical lead passing along one side of the single projection, through the corresponding attachment member body and along another side of the single projection.  
         [0050]      FIGS. 7, 8 ,  9  and  10  depict attachment of sensor assembly  30  to a heat exchanger  24 . Heat exchanger  24  includes a plurality of hollow core passages  70  which contain a cooling medium. A plurality of heat exchanger cooling fins  72  are in contact with cores  70  and provide passageways  73  through which ambient air flows to remove heat conducted into the fins. The width  78  of the passageways is shown on  FIG. 7  and is roughly equivalent to the width of cores  70 . Referring to  FIG. 2b , projections  54  and receptacles  56  are adapted and configured such that there is a predetermined length  48  from the surface of resilient pad  80 . 1  to the surface of resilient pad  80 . 2 . This predetermined distance  48  is preferably less than width  78 . This difference between length  48  and width  78  is accommodated by compression of resilient pads  80 . 1  and  80 . 2  on an installed sensor  30 .  
         [0051]     Referring again to  FIGS. 7, 8 ,  9  and  10 , projections  54  of attachment member clip assembly are each inserted through a corresponding passageway  73  established by cooling fins  72 . For example, projection  54 . 1  is inserted through a passageway  73 . 1 ; projection  54 . 2  is inserted through a passageway  73 . 2 ; projection  54 . 3  is inserted into a passageway  73 . 3 ; and projection  54 . 4  is inserted through a passageway  73 . 4 . These projections  54  of attachment member clip assembly  50  are pushed through the corresponding passageway  73  from a side  76  of heat exchanger  24 . This insertion continues until resilient pad  80 . 2  is in contact with heat exchanger side  76 . The projections  54  of attachment member clip assembly  50  have a length  55  which is preferably greater than width  78  of the passageway between cores  70 . Because of this difference between length  55  and width  78 , the ends of projections  54  protrude through the other side  74  of heat exchanger  24 .  
         [0052]     Following insertion of clip assembly  50  into heat exchanger  24 , the receptacles  56  of sensor case  32  are brought into alignment with the corresponding protruding projections  54 . The reception of projections  54  within the corresponding receptacle  56  guides sensor case  32  into the proper position on the opposite side  74  of heat exchanger  24 . When all projections are inserted into the corresponding receptacles, compression is applied to clip assembly  50  and sensor case  32  until the projection spring clips  58  snaps into place with the corresponding projection retaining springs  60  (as previously seen in  FIG. 6 ). The compression of clip assembly  50  and sensor case  32  results in compression of resilient pads  80 . 1  and  80 . 2 , an installed state of tension in projections  54 , and a corresponding snug fit of sensor assembly  30  onto heat exchanger  24 .  
         [0053]     Referring specifically to  FIGS. 9   a  and  9   b,  the sensor assembly  30  of  FIG. 2   a  is shown having portions of the sensor case  32  cut away to show the orientation of the thermistors  40 . 2 ,  40 . 3  relative to the heat exchanger  24 . In  FIG. 9   a,  the thermistors  40 . 2 ,  40 . 3  are shown aligned equidistant from the heat exchanger  24  such that it is expected that the thermistors  40 . 2 ,  40 . 3  will detect the same temperature. This temperature reading will be transmitted to the signal processor  26  via the lead wires  34 .  
         [0054]     In the configuration shown in  FIG. 9   a,  the proper orientation of the sensor case  32  relative to the heat exchanger  24  results in a minimal difference between the temperature readings of the thermistors  40 . 2 ,  40 . 3 . As such, the signal processor  26  is adapted to verify that the temperature readings of the thermistors  40 . 2 ,  40 . 3  are within a specified range in order to confirm the proper orientation of the sensor case  32 . Any deviation in the temperature readings of the thermistors  40 . 2 ,  40 . 3  that falls outside of the predetermined range will indicate to the signal processor  26  that the sensor case  32  is not properly aligned, and further that the sensor assembly  30  of the present invention has been tampered with.  
         [0055]     For example,  FIG. 9   b  shows a second, improper orientation of the sensor case  32  relative to the heat exchanger  24 . As shown, the sensor case  32  has been rigged or fitted to the heat exchanger via connections  50 . 1  and  50 . 2 , wherein connection  50 . 1  maintains the electrical circuit within the sensor assembly  30  as described above. Accordingly, it would otherwise be conceivable to attach the sensor case  32  of the present invention to the heat exchanger  24  without breaking any electrical circuit.  
         [0056]     However, as shown in  FIG. 9   b,  the orientation of the sensor case  32  is such that the first thermistor  40 . 2  is further from the heat exchanger  24  than the second thermistor  40 . 3 . The spatial difference between the placement of the thermistors  40 . 2 ,  40 . 3  will result in a temperature difference as well, such that communication of the relative temperature of the thermistors  40 . 2 ,  40 . 3  to the signal processor  26  will result in evidence of tampering with the sensor case  32 . By arranging the thermistors  40 . 2 ,  40 . 3  in such a manner, the present invention thus provides another means by which tampering with the sensor assembly  30  can be detected.  
         [0057]     In alternate embodiments, the circuit board  40 . 1  may support a plurality of thermistors, such as those described above, arranged in selected arrays for ensuring the geometric alignment of the sensor case  32  relative to the heat exchanger  24 . For example, it may be preferable for certain applications to include three thermistors arranged in a triangular array so as to form a geometric plane that it coplanar with the surface of the circuit board  40 . 1 . Additional thermistors may be added in order to provide redundant temperature measurement signals and to better determine the proper range within which the signal processor  26  will recognize correct alignment.  
         [0058]     As best seen in  FIGS. 5 and 6 , the projection spring clip  58  located near the free end of the corresponding projection  54  is displaced inwardly toward the interior of sensor case  32 . It can be appreciated that any external inward pushing on a spring clip  58 , such as by a user with a tool, does not free the corresponding ledge of projection  58  from engagement with the corresponding ledges on the pair of retaining springs  60 . Therefore, it is difficult to disassemble clip assembly  50  from sensor case  32 , since spring clips  58  must instead be pulled outward to disengage the projection from the receptacle. Further, sensor case body  36  (which has been removed from  FIG. 6  for clarity) preferably does not include any apertures through which a user could insert a tool or any other external features that could be used in an attempt to disengage the projections from the receptacles and remove sensor  30  from its assembled state on heat exchanger  34 .  
         [0059]      FIGS. 11-14  depict a sensor assembly  130  according to another embodiment of the present invention. The use of a one hundred prefix ( 1  XX) with an element number (XX) indicates a feature of the embodiment that is the same as the non-prefixed element number (XX), except for those changes shown or described.  
         [0060]     In another embodiment of the present invention, a sensor assembly  130  is attached to a heat exchanger  24  in a vehicular system  120 . Preferably, sensor  130  is attached to a heat exchanger such that removal of sensor assembly  130  from the heat exchanger leaves mechanical evidence and/or electronic evidence of the removal. In yet another embodiment, sensor assembly  130  is in electrical communication with a signal processor  126  and provides an indication if sensor  130  is removed from heat exchanger  24 .  
         [0061]     Sensor assembly  130  includes a sensor case  132  with one or more lead wires  134  extending from a side of the sensor case. Assembly  130  also includes an attachment member clip assembly  150  that preferably includes one or more projections  154 . Projections  154  are adapted and configured to be received within one or more receptacles  156  of sensor case  132 . Sensor assembly  130  further includes a circuit board  140 . 1  contained within sensor case  132 .  
         [0062]     The internal construction and sensor operation of sensor assembly  130  is generally the same as that of sensor assembly  30 . In one embodiment, circuit board  140 . 1  includes a first sensor for detecting electrical continuity, and a plurality of thermistors (not shown) oriented in one of the preferred fashions described above. In one embodiment, the continuity path includes one or more lead wires  134 , one or more projections  154 , and one or more internal circuit board clips  142 . The operation of the circuit board clips, receptacles, and projections of sensor assembly  130  are the same as that for sensor  30 .  
         [0063]     There are several external differences between sensor assembly  130  and sensor assembly  30 . Sensor assembly  130  includes a plurality of lead wires  134  that extend laterally from a side of sensor case  132 , as best seen in  FIGS. 12 and 13 . Sensor case body  36  preferably does not include a plurality of sensor cooling fins. It has been found in some embodiments that there can be excessive cooling of the attachment clip and projections, such that the temperature sensed by the temperature measurement device is too low and/or too slow acting. Removal of the cooling fins can improve the response of the thermistors.  
         [0064]     One embodiment of the present invention was tested with an attachment clip similar to attachment clip  50 . In that application, sensor assembly  30  was oriented such that attachment member body  52  was directed toward the front of the vehicle, such that there was direct impingement of cooling flow onto the front face of attachment member body  52 . It was found that at some vehicle speeds, there could be a difference of 20-30 degrees C. between the radiator and a temperature measured by the thermistors. This temperature difference may be caused by an improvement in heat rejection caused by assembly  50 . For those applications in which this temperature drop is not desirable, it is possible to add an air dam and/or thermally insulating material onto the front of body  52 . For those applications in which it is desired to have a further lessening of the temperature difference, it is possible to extend the edges of resilient pad  53  beyond the edges of body  52  so as to block incoming air from the projections  54 .  
         [0065]     In some embodiments, still further improvement of the response of an internal temperature sensor is desirable. Attachment clip member assembly  150  includes an air dam and thermal insulator  180 . 3  which is mounted to the surface of attachment member body  152  that is opposite to the surface which resilient pad  180 . 2  is mounted, as best seen in  FIGS. 11 and 15 . In one embodiment, air dam  180 . 3  projects a frontal area toward the cooling air passing over heat exchanger core  70  that is greater than the frontal area of attachment member body  152 , and in some embodiments greater than the projected frontal area of sensor case  1 . 32 . Air dam  180 . 3  impedes air flow which would otherwise cool sensor assembly  130  and therefore improves heat transfer from the heat exchanger into clip  150  and into sensor case  132 . In one embodiment, air dam  130  is fabricated from a resilient material such as silicone rubber or PORON® material.  
         [0066]     In some embodiments, air dam  180 . 3  is fabricated from a material with low thermal conductivity in order to impede the transfer of heat from the cooling flow to clip  150 . However, the present invention contemplates those embodiments in which pad  180 . 3  is an air dam and not a thermal insulator, as well as those embodiments in which pad  180 . 3  provides only reduced alteration of the impinging air flow, but provides thermal insulation.  
         [0067]      FIGS. 16 and 17  show perspective and end views, respectively, of attachment clip member assembly  150 .  FIG. 16  is a scaled drawing according to one embodiment of the present invention. In that embodiment, dimension A is about 1.00 inches, and dimension B is about 0.75 inches. In that embodiment, air dam  180 . 3  is a foam pad of closed cellular silicone material, such as BISCO HT-805(5) or equivalent material. Further, resilient pad  180 . 2  is fabricated from closed silicone material, such as BISCO HT-805(5) or equivalent. The projections  154 . 1 ,  154 . 2 ,  154 . 3 , and  154 . 4  are fabricated from a material such as 3003 1414 aluminum. Although specific dimensions and materials have been shown and described, it is understood that the present invention is not so limited.  
         [0068]     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.

Technology Category: 2