Tamper evident connector for an engine radiator

Abstract

The present invention includes a system and method for providing assurance and evidence that a particular part has been installed and properly maintained. In particular, automotive sensing systems may be incorporated into two-part sensor assemblies that are disposable within a vehicle. The sensor assemblies are adapted to provide evidence of tampering via mechanical, electrical and temperature-based means. In a preferred embodiment, the sensor assembly is disposed about an automotive heat exchanger and a plurality of thermal sensors measure the temperature of the heat exchanger. Any alteration in the orientation or placement of the sensor assembly causes a variance between the temperatures measured by the thermal sensors, which in turn provides clear indication of tampering to the driver.

Description

FIELD OF THE INVENTION

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

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.

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.

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.

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

Accordingly, the present provides a sensor and a method of utilizing the sensor that provides evidence of tampering therewith.

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.

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

FIG. 1 is a schematic representation of a system according to one embodiment of the present invention.

FIG. 2a is a top plan view of a sensor assembly according to one embodiment of the present invention.

FIG. 2b is a side elevational view of the sensor assembly of FIG. 2a.

FIG. 2c is an end elevational view of the sensor assembly of FIG. 2a.

FIG. 2d is a perspective view of the sensor assembly of FIG. 2a.

FIG. 3 is a sectional view of the sensor assembly of FIG. 2a as taken along line 3-3 of FIG. 2a.

FIG. 4 is a bottom plan view of a circuit board assembly in accordance with the present invention.

FIG. 5 is an exploded perspective view of the sensor assembly of FIG. 2a.

FIG. 6 is a perspective view of the sensor assembly of FIG. 2a with the case body removed.

FIG. 7 is an exploded view of the sensor assembly of FIG. 2a positioned to be inserted into a portion of a heat exchanger.

FIG. 8 is a perspective view of the sensor assembly of FIG. 2a assembled onto a portion of a heat exchanger.

FIG. 9a is a side elevational view of the sensor assembly of FIG. 2a properly disposed about a heat exchanger in a first orientation.

FIG. 9b is a side elevational view of the sensor assembly of FIG. 2a disposed about a heat exchanger in a second orientation such that evidence of tampering is recognized.

FIG. 10 is a perspective view of the sensor assembly of FIG. 2a assembled onto a portion of a heat exchanger.

FIG. 11 is a side elevational view of a sensor assembly according to another embodiment of the present invention.

FIG. 12 is a bottom plan view of a portion of the sensor assembly of FIG. 11.

FIG. 13 is a cross sectional view of the apparatus of FIG. 11 as taken along line 13-13 of FIG. 12.

FIG. 14 is a perspective view of the apparatus of FIG. 11.

FIG. 15 is a perspective view of the sensor assembly of FIG. 10 assembled onto a portion of a heat exchanger.

FIG. 16 is an end perspective view of a portion of the apparatus of FIG. 10.

FIG. 17 is an end plan view of the apparatus of FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENT

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.

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.

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's control system.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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. 2b and 2d, 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.

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.

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.

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.

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.

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.

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.

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.

Referring specifically to FIGS. 9a and 9b, the sensor assembly 30 of FIG. 2a 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. 9a, 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.

In the configuration shown in FIG. 9a, 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.

For example, FIG. 9b 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.

However, as shown in FIG. 9b, 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Claims

1. A tamper evident system connectable to heat exchanger having cooling fins, the system comprising:

a sensor case disposed on a first side of a heat exchanger;

an attachment member disposed on a second side of a heat exchanger;

a first thermistor and a second thermistor disposed within the sensor case, the first thermistor adapted to measure a first temperature and the second thermistor adapted to measure a second temperature; and

a signal processor in communication with the first and second thermistor, the signal processor adapted to receive signals indicative of the first temperature and the second temperature, the signal processor further adapted to provide evidence of tampering in response to a predetermined variance between the first temperature and the second temperature.

2. The system of claim 1 wherein the attachment member further comprises a projection adapted to project through the cooling fins of the heat exchanger, the projection further adapted to be received by the sensor case.

3. The system of claim 2 wherein the sensor case further comprises a receptacle adapted for receiving the projection.

4. The system of claim 3 wherein the projection and the receptacle are adapted to lock together in interference when the projection is inserted into the receptacle.

5. The system of claim 2 wherein the projection is electrically conductive.

6. The system of claim 1 further comprising a circuit board disposed within the sensor case, the circuit board in electrical communication with the signal processor.

7. The system of claim 6 wherein the first thermistor and the second thermistor are disposed on the circuit board and further wherein the first thermistor and the second thermistor are in electrical communication with the signal processor through the circuit board.

8. The system of claim 7 wherein the first thermistor is disposed on a first end of the circuit board and the second thermistor is disposed on a second end of the circuit board.

9. The system of claim 6 wherein the circuit board is disposed within the sensor case such that the circuit board can be aligned in a substantially coplanar fashion with the heat exchanger.

10. The system of claim 1 further comprising a third thermistor adapted to measure a third temperature.

11. The system of claim 10 wherein the signal processor is in communication with the first, second, and third thermistors, the signal processor adapted to receive signals indicative of the first temperature, the second temperature and the third temperature, the signal processor further adapted to provide evidence of tampering in response to a predetermined variance between the first temperature, the second temperature and the third temperature.

12. A tamper evident system connectable to heat exchanger having cooling fins, the system comprising:

a sensor case disposed on a first side of a heat exchanger;

an attachment member disposed on a second side of a heat exchanger;

means for measuring a temperature of the heat exchanger;

means for measuring electrical conductivity; and

means for providing evidence of tampering with the system in response to predetermined changes in the measured temperature or electrical conductivity.

13. The system of claim 12 wherein the means for measuring the temperature of the heat exchanger includes an array of thermistors disposed on within the sensor case and adjacent to the heat exchanger.

14. The system of claim 13 wherein the array of thermistors is disposed on a circuit board housed within the sensor case.

15. The system of claim 13 wherein the array of thermistors includes two thermistors.

16. The system of claim. 13 wherein the array of thermistors includes at least two thermistors.

17. A method of determining the presence of a sensor assembly relative to a heat exchanger, the method comprising the steps of:

providing a sensor assembly including a first thermistor and a second thermistor;

orienting the first and second thermistor relative to the heat exchanger;

detecting a first temperature with the first thermistor and a second temperature with the second thermistor;

calculating a variance between the first temperature and the second temperature; and

determining the presence of the sensor assembly relative to the heat exchanger in response to the variance between the first temperature and the second temperature.

18. The method of claim 17 further comprising the step of forming an electrical circuit, the electrical circuit formed around a portion of the heat exchanger.

19. The method of claim 18 further comprising the step of determining the presence of the sensor assembly relative to the heat exchanger in response to a break in the electrical circuit.

20. The method of claim 17 further comprising the step of providing a third thermistor in the sensor assembly.

21. The method of claim 17 wherein the step of orienting the first thermistor and the second thermistor relative to the heat exchanger includes disposing the first thermistor and the second thermistor on a substantially planar surface and further orienting the substantially planar surface relative to the heat exchanger.

22. The method of claim 21 wherein the substantially planar surface is a circuit board.

23. The method of claim 21 wherein the substantially planar surface is oriented substantially coplanar to the heat exchanger.