Coating wear sensor assembly for monitoring deterioration of heat exchanger coating

Abstract

A heat exchanger assembly includes a coated core and an electronic coating wear sensor assembly mounted adjacent to the coated core for monitoring depletion of a coating layer of the core. The coating wear sensor assembly is electrically insulated from the coated core to ensure that an electric circuit of the coating wear sensor assembly does not affect deterioration of the core. The sensor assembly has a pair of spaced electrodes electrically insulated from each other by an insulating spacer forming a coating sample area coated with a sample layer of the coating material that provides conductive bridge between the electrodes. The coating sample area is coated with the same coating composition of the same thickness as the heat exchanger core in order to replicate the same rate coating degradation. The coating wear sensor assembly is connected to a sensing circuit that outputs to a coating condition diagnostic unit.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application relates to and claims priority under 35 U.S.C. 119(e) of U.S. Provisional Patent Application Ser. No. 60/326,318, filed on Oct. 1, 2001; U.S. Provisional Patent Application Ser. No. 60/329,175, filed on Oct. 12, 2001; U.S. Provisional Patent Application Ser. No. 60/329,187, filed on Oct. 12, 2001; and U.S. Provisional Patent Application Ser. No. 60/330,271, filed on Oct. 18, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention pertains in general to heat exchangers and, more particularly, to a coated heat exchanger provided with a coating wear sensor for monitoring deterioration of a coating layer of the heat exchanger.

[0004] 2. Description of the Prior Art

[0005] A heat exchanger core is a primary component of what defines a heat exchanger and can also be described as a substrate structure. Vehicle heat exchanger applications commonly have the heat exchanger core positioned in-line with the incoming airflow stream. This airflow stream comes from the grille or other openings located in front of the vehicle. This allows incoming air to be carried through the heat exchanger and pass away through an engine compartment.

[0006] Coatings of surfaces of an object, such as paint coatings, are used for many reasons, the simplest of which is to improve the visual appearance of the object. For automotive engine cooling applications, a coating that adheres to any part of heat exchanger surfaces and is not significantly affected by high temperatures is a potential coating candidate. An example of this is seen when an automotive heat exchanger specifically has paint applied to its front surface to improve the visual appearance of the vehicle when observed through the front grille. Coatings can either adhere by the fact that the coating itself being applied exhibits adhesive characteristics or the addition of a glue adhesive may be utilized. Various processing approaches during the manufacturing of a heat exchanger such as heating or drying the applied coating can also promote coating adherence to the heat exchanger surface. Coatings are added to protect portions of the heat exchanger for reasons of protecting surface areas from corrosion. A dichromate corrosion preventative describes one of these types of coatings.

[0007] One of the newer types of coating being applied to the heat exchangers is a catalytic coating for the purpose of reducing airborne pollutant elements that pass through the heat exchanger core, such as PremAir® Catalyst Systems of Engelhard Corp. (Iselin, N.J.). The catalytic pollutant-reducing coatings can be applied to the heat exchangers that are mobile as well as stationary. The catalytic coating application should not be limited to only automotive applications, but may have other mobile applications, such as marine, aerospace, etc.

[0008] However, the air emissions reducing catalytic coatings applied to the under-hood heat exchangers of the motor vehicles, have a tendency to become depleted over time, such as from extremely high ambient temperature, wind and dust erosion, high pressure washes and/or some harsh cleaning agents which are sometimes used in the engine compartment. Any of these conditions or others could potentially affect the adherence of the coating. The coating effectiveness is considered to be active until it is nearly depleted. The larger the initial surface area covered with the coating, the better the overall emissions performance. The larger the amount of coating added to the core surface, the better chance of the coating will last for the life of the heat exchanger. Some coatings were found to have a some electrical resistance that changes as the coating wears away.

[0009] The heat exchanger is placed in a location of high airflow for maximum heat transfer to the air. The contaminants and pollutant elements in the air also pass across the heat exchange surfaces of the core. Abrasive contaminants in the air pass along the surfaces of the heat exchange area on which the coating is applied. Coating erosion depends on the amount of contaminants in the incoming air and the air velocity that carries them over the coating. Normally the erosion of the coating would occur in the coating areas receiving the most direct airflow and highest airflow volumes. Thus, for earliest detection of degradation, the coating sampling area should be located in the area of highest airflow over the coated surfaces of the heat exchanger (for the coated surfaces being validated).

[0010] It has been realized that a sensor is required to monitor the depletion of the heat exchanger core coating over time. The purpose for the sensor requirement is to make sure that the coating is present and has been described as an emission-reducing device for the improvement to the air quality. The electronic sensor can detect coating failure by running a small current through the coating to detect the change in electrical resistance. However, the electronic sensors attached to the core can cause galvanic corrosion to occur when current passes through the core. The electronic coating sensor requires a small current to be passed through the coating to detect a change in the materials electrical properties indicating when the coating is depleted. Automotive heat exchangers are made of very thin materials and can be easily damaged by galvanic corrosion when a current passes through the core. The coating sensor uses current passed through the coating to monitor its presence by measuring the change in resistance. As the current passes through the coating of a heat exchanger core it also passes through the core fins and tubes. Galvanic corrosion can occur during this time and eventually cause the core to fail. Passing current through the core can stimulate the corrosion also. Transient currents as small as 150 milli-volts DC can cause failure of the core in the “short term”. Lower voltages over a longer period of time may cause “long term” electrolytic corrosive failure eventually causing leakage through the heat exchanger tubes.

[0011] The elevated surface temperature of the heat exchanger core enhances the process of reducing the pollutant elements in the air that passes through. The heat exchanger core fins and tubes are made of very thin metal materials and are more susceptible to damage from contact with other closely mounted components as well as corrosion from both normal road salts and other airborne contaminants. Elevated temperatures increase the rate of corrosion especially to the core fins and tubes. Some heat exchanger operating temperatures are the engine radiator, which generally operates above 90° C., the condenser at about 70° C. and transmission cooler at above 70° C. An elevated ambient temperature above the normal 23° C. further elevates the operating temperatures of the individual heat exchangers.

[0012] The thin tubes and fins are also susceptible to galvanic corrosion created when stray electric current is accidentally routed through the heat exchanger core and is most usually caused by improperly grounding of an electrical system of the vehicle.

[0013] Therefore, it would be desirable to provide an improved coating wear sensor assembly that would not cause the damaging galvanic corrosion to the heat exchanger core.

SUMMARY OF THE INVENTION

[0014] It is an object of the present invention to provide a novel coating wear sensor assembly for monitoring depletion of a coating layer of a coated heat exchanger assembly, especially for automotive application, without causing damage to a heat exchanger core.

[0015] The present invention is directed to the coated heat exchanger assembly including a coated heat exchanger core and the coating wear sensor sensor mounted adjacent to the coated heat exchanger core in such a manner as to provide a coating sample area coated with a sample layer of the same coating material as the heat exchanger core, and having the same thickness, thus insuring that the coating on sample area is equivalent of the coating on the heat exchanger core, which would give an accurate measurement of the coating degradation. Furthermore, the coating wear sensor assembly is electrically insulated (or separated) from the coating layer of the heat exchanger core. The separation of the sensor assembly would prevent stray current from passing through the heat exchanger core by isolating the sensor coating sample area from the heat exchanger core. The electronic sensor assembly would have an offset sensor coating sample area electrically isolated from the coated core surface and having the exact same compound and thickness of the rest of the core coating would give an accurate measurement of the degradation. The coating sensor electrical signal would not cause damage to the core tubes or fins.

[0016] The coating wear sensor assembly in accordance with the present invention detects coating failure by running a small electric current through the coating layer in the coating sample area to detect the change in an electrical resistance of the electrical current flowing therethrough. As the coating layer deteriorates, the electrical resistance of the coating layer changes. Thus, the failure of the coating layer may be detected.

[0017] The coating wear sensor assembly is placed in the area of greatest erosion, which is in the direct airflow path through the heat exchanger core. Preferably, the sensor assembly is mounted adjacent to a face of the heat exchanger core itself or suspended over the core face from a remotely mounted base such as heat exchanger tanks for the sensing area to reflect the erosion characteristics of the core.

[0018] The coating is applied directly to the core face in intermittent or continuous coverage. The coating may be applied prior to assembly to separate components (e.g. with the same composition batch, and preferably to the same thickness) or to an entire assembled assembly. The sensor assembly is mounted in the core area and receives equivalent coating coverage as the rest of the core.

[0019] Therefore, the present invention provides the novel coating wear sensor assembly for monitoring depletion of the coating layer of the coated heat exchanger assembly without causing damage to a heat exchanger core.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1a is a partial perspective view of a heat exchanger assembly during a process of coating a heat exchanger core;

[0021] FIG. 1b is a partial perspective view of the heat exchanger assembly in combination with a coating wear sensor assembly of the present invention during a process of coating the heat exchanger core and the coating wear sensor assembly;

[0022] FIG. 2a is a partial perspective view of the heat exchanger assembly and the coating wear sensor assembly in accordance with the first exemplary embodiment of the present invention mounted to the heat exchanger core;

[0023] FIG. 2b is a perspective view of the coating wear sensor assembly in accordance with the first exemplary embodiment of the present invention;

[0024] FIG. 3 is a is schematic diagram of a sensing circuit for monitoring coating deterioration;

[0025] FIG. 4a is a partial perspective view of the heat exchanger assembly and the coating wear sensor assembly in accordance with the second exemplary embodiment of the present invention mounted to the heat exchanger core;

[0026] FIG. 4b is a perspective view of the coating wear sensor assembly in accordance with the second exemplary embodiment of the present invention;

[0027] FIG. 4c is a cross-sectional view of the coating wear sensor assembly in accordance with the second exemplary embodiment of the present invention;

[0028] FIG. 5a is a partial perspective view of the heat exchanger assembly and the coating wear sensor assembly in accordance with the third exemplary embodiment of the present invention mounted to the heat exchanger core;

[0029] FIG. 5b is a perspective view of the coating wear sensor assembly in accordance with the third exemplary embodiment of the present invention;

[0030] FIG. 6a is a perspective view of the heat exchanger assembly and the coating wear sensor assembly in accordance with the fourth exemplary embodiment of the present invention mounted to the heat exchanger core;

[0031] FIG. 6b is a perspective view of the coating wear sensor assembly in accordance with the fourth exemplary embodiment of the present invention in disassembled condition;

[0032] FIG. 6c is a perspective view of the coating wear sensor assembly in accordance with the fourth exemplary embodiment of the present invention in assembled condition;

[0033] FIG. 6d is a partial perspective view of the heat exchanger assembly and the coating wear sensor assembly in accordance with the fourth exemplary embodiment of the present invention mounted to the heat exchanger core;

[0034] FIG. 7 is a partial perspective view of a vehicular heat exchanger module including an engine cooling radiator and a condenser an air conditioning system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035] The preferred embodiment of the present invention will now be described with the reference to accompanying drawing.

[0036] The preferred embodiment of the present invention is directed to a system including different components, particularly a coated heat exchanger, assembled into a module. The components of the system may be separately or integrally fabricated or assembly. The components may include, for instance, a radiator heat exchanger, a condenser heat exchanger, an engine oil cooler heat exchanger, a transmission oil cooler heat exchanger, or the like, fans, shrouds or other under-the-hood components. Preferably, the modules or systems include at least 2 of the above components, more preferably at least 3 or more. The invention is especially adapted for use in particular automotive applications and for vehicular heat exchangers, such as a radiator of an engine cooling system and/or a condenser of an air-conditioning system.

[0037] Referring to FIGS. 1a, 1b and 2a of the drawings, a heat exchanger assembly in accordance with the present invention, generally denoted by reference numeral 10, for use in a conventional cooling system of a motor vehicle, is illustrated. The heat exchanger assembly 10 comprises a first tank 12, a second tank 14 and a heat exchanger core 16 extending between the first tank 12 and the second tank 14. The heat exchanger core 16 comprises a series of substantially parallel spaced tubes 18 and a series of fins 20 located between the tubes 18. One ends of the tubes 18 are open into the first tank 12, while the opposite ends of the tubes 18 are open into the second tank 14.

[0038] The heat exchanger core 16 of the present invention is covered with a layer 30 of a coating material 32 that is electrically conductive. Preferably, the coating material 32 is a catalytic coating composition provided for reducing airborne pollutant elements that pass through the heat exchanger core 16. Here the heat exchanger core 16 can be described as a substrate structure. As air passes through the heat exchanger core 16 over the coated surface thereof, a chemical reaction occurs between the passing air and the catalytic coating composition 32 in which ozone, the main ingredient of smog, and carbon monoxide are changed into oxygen and carbon dioxide, respectively. This rids the air of ground-level ozone, thus decreasing smog, and poisonous carbon monoxide. This process occur while the car is moving, but also while the car is parked, as radiator fans could operate and keep air circulating, converting more air.

[0039] As an example of such catalytic coating material 32 may be named PremAir® Catalyst System of Engelhard Corp. (Iselin, N.J.) which is a platinum-based coating on the vehicular heat exchanger, that converts ozone into oxygen and carbon monoxide into carbon dioxide.

[0040] As illustrated in FIG. 1a, the heat exchanger core 16 is sprayed with the coating material 32 from a spray gun nozzle 34 in a spray pattern, which is shaped by mechanical baffles or blades (not shown) of air to limit the overspray of the coating material 32 to the areas of the heat exchanger assembly 10 other than the heat exchanger core 16, such as the tanks 12 and 14 and core side plates. The coating material 32 can be applied to either one or both sides of the heat exchanger core 16 and penetrating some distance into the heat exchanger core 16, but not completely through to the other side thereof.

[0041] The coating application is illustrated in FIGS. 1a and 1b by a simple spray process employing the conventional spray gun nozzle 34. It will be appreciated by those of ordinary skills in the art that any other appropriate coating process and device, such as a more complex and sophisticated automated coating spray process line for high volume automotive production applications, is within the scope of the present invention.

[0042] The heat exchanger 10 is placed in a location of high airflow for maximum heat transfer to the ambient air. The contaminants and pollutant elements in the air also pass across the heat exchange surfaces of the core 16. Abrasive contaminants in the air pass along the surfaces of the heat exchange area on which the coating layer 30 is applied. Coating erosion can occur relative to the amount of contaminants and the air velocity that carries them over the coating. Normally the erosion of the coating layer 30 would occur in the coating areas receiving the most direct airflow and highest airflow volumes.

[0043] In order to ensure the proper condition of the catalytic coating layer 30 during the operation of the motor vehicle, the heat exchanger assembly 10 of the present invention further includes an electronic coating wear sensor assembly (or coating layer depletion monitoring sensor) for monitoring the depletion of the coating layer 30 over time. The purpose for the sensor assembly is to make sure that the coating layer 30 is present and functioning as an emissions device for the improvement to the air quality. The coating wear sensor assembly in accordance with the preferred embodiment of the present invention has at least one pair of spaced electrodes electrically insulated from each other by an insulating spacer. The coating wear sensor assembly in accordance with the present invention includes a sensor head and a fastener member adapted to secure the sensor head adjacent to the heat exchanger core 16. The sensor head has at least one pair of spaced electrodes electrically insulated from each other by an insulating spacer. A surface of the sensor head adjacent to the electrodes, including outer peripheral surfaces of the electrodes, is coated with a sample layer of the coating material, thus forming a coating sample area. The sample layer of the coating material provides a conductive bridge between the electrodes. The coating sample area is coated with the same coating material 32 as the core 16, and with the same thickness. Thus, the sensor coating sample area would be an equivalent sample to the coating on the main body of the core by applying the same coating to the core and sensor area. The purpose for having the same coating on the core and sensor is to establish confidence that the sample being tested by the sensor is an accurate indicator of what is actually happening to the core coating.

[0044] The coating wear sensor assembly in accordance with the present invention detects coating failure by running a small electric current through the coating layer 30 in the coating sample area to detect the change in an electrical resistance of the electrical current flowing therethrough. As the catalytic coating layer 30 deteriorates during the lifetime of the motor vehicle, the electrical resistance of the catalytic coating layer 30 changes. Thus, the failure of the catalytic coating layer 30 may be detected. However, it is possible to use other appropriate sensors known in the art.

[0045] The electronic sensor of the present invention is provided for testing the degradation of the core coating without causing damage to the core 16 of the heat exchanger 10 by preventing a sensor current from passing through the tubes 18 and the fins 20 thereof, thus avoiding galvanic corrosion that can occur therein. For this purpose, the coating wear sensor assembly (especially the coating sample area thereof) of the present invention is electrically insulated from the coating layer of the heat exchanger core 16.

[0046] The separation of the sensor assembly from the core 16 prevents stray current from passing through the core 16 by isolating the sensor coating sample area from the coating layer 30 of the core 16. The coating sample area of the coating wear sensor assembly is offset and electrically isolated from the coated surface of the heat exchanger core 16. Thus, the electrical signal of the coating failure sensor would not cause damage to the core tubes or fins. The exact same composition and thickness of the coating sample area of the coating wear sensor assembly as the rest of the core coating provides an accurate measurement of the coating depletion.

[0047] Therefore, the sample layer of the coating sample area is provided to replicate coating degradation at the same rate as the coating layer 30 of the coated heat exchanger core 16.

[0048] For earliest detection of degradation the coating layer 30, the sensor assembly is mounted in the area of greatest erosion, which is in the direct airflow path through the core 16, and is, preferably, located in the area of highest airflow through the coated surfaces. This means the sensor is mounted on a face surface of the core 16 or, alternatively, suspended over the core face surface from a remotely mounted base such as the heat exchanger tanks 12 and 14 for the sensing area to reflect the erosion characteristics of the core 16.

[0049] The coating material 32 is applied directly to the core face in a continuous or intermittent coverage. It can be applied to the coating sample area after the sensor and core are assembled, or separately, before assembly (e.g. by coating the sensor separately but with the same batch of coating material, and preferably the same thickness). It will be appreciated by those skilled in the art that various appropriate techniques of coating the coating sample area of the sensor body with coating material 32 may be employed, such as spraying, brushing, dipping, etc.

[0050] The coating wear sensor assembly of the present invention can also be provided with an ID tag to identify the date of applying the coating layer 30 to the heat exchanger assembly 10 and/or the composition of the coating material 32. It will be appreciated by those skilled in the art that the ID tag may be in any appropriate form, such as a physical imprint on the coated surface, barcode or an attachment to the sensor assembly. Furthermore, the ID tag can also be used to provide information about the manufacturer and time and location of manufacturing plant.

[0051] In the first exemplary embodiment of the present invention, illustrated in detail in FIGS. 2a and 2b, the electronic coating wear sensor (or coating layer depletion monitoring sensor), generally denoted by reference numeral 40, is mounted to the heat exchanger core 16 in an area of high airflow therethrough. As illustrated, the sensor assembly 40 comprises a sensor body 42 and a fastener assembly 52. The sensor body 42 includes a pair of substantially disk-shaped electric electrodes 44a and 44b separated to a specified distance by a substantially disk-shaped insulator spacer 46. Preferably, the insulator spacer 46 has substantially the same outer diameter as the electric contacts 44a and 44b. Together circumferentially outer peripheral surfaces of the electric electrodes 44a and 44b and the insulator spacer 46 form a coating sample surface 43. The sensor body 42 further includes an insulator cover 48 disposed between the sensor body 42 and the heat exchanger core 16. The insulator cover 48 electrically isolates the coating sample surface 43 of the sensor assembly 40 from the heat exchanger core 16, thus preventing stray current from passing through the core 16.

[0052] Each of the electrodes 44a and 44b is electrically connected to a conductive terminal (45a and 45b, respectively) to which an electrical wire harness assembly would be attached.

[0053] The fastener assembly 52 in accordance with the first exemplary embodiment of the present invention includes a fastener member 54 and a retainer 56 adapted to threradedly engage the fastener member 54. The fastener member 54 is made of the any appropriate electrically insulator material, such as plastic. The fastener member 54 has a threaded shaft 54a adapted to threradedly engage the retainer 56 from one end of the threaded shaft 54a and a substantially annular flat head 54b provided at the opposite end thereof. It will be appreciated by those skilled in the art that the shaft 54a may not necessarily be threaded and that any appropriate manner of securing the retainer 60 to the shaft 54a is within the scope of the present invention.

[0054] Alternatively, the fastener member 54 may be made of a heat conductive material, such as metal or ceramic. The heat conductive material of the fastener member 54 functions as a heat conducting conduit that carries thermal energy from the heat exchanger core 16 to the coating sample surface 43 thereby substantially equalizing the temperature thereof with the temperature of the heat exchanger core 16. In this embodiment, the insulator spacer 46 of the sensor body 42 electrically separates the contacts 44a and 44b from the fastener member 54.

[0055] In an assembled condition, the threaded shaft 54a of the fastener member 54 extends through corresponding bore in the sensor body 42, penetrates through and between the core fins 20 and is threaded into the retainer 56, thus firmly securing the sensor body 42 adjacent to the core 16 and both the core 16 and the sensor body 42 are held in between the retainer 56 and the flat head 54b of the fastener member 54, as illustrated in FIG. 2a. Preferably, the retainer 56 is provided with a series of ribs adapted to firmly engage the tubes 18 of the heat exchanger core 16.

[0056] Preferably, as shown in FIG. 2a, the sensor body 42 is mounted in front (relative to the direction of the airflow through the heat exchanger 10) of the heat exchanger core 16, as shown in FIG. 2a. Alternatively, the sensor body 42 may be mounted behind the heat exchanger core 16, where the sensor body 42 is clamped between the core 16 and the retainer 56, as shown in FIG. 2b.

[0057] As illustrated in FIG. 1b, after the depletion monitoring sensor 40 is mounted to the heat exchanger core 16, the sensor body 42 is sprayed with the same coating material 32 as the heat exchanger core 16, from a spray gun nozzle 34, in order to coat the coating sample area 43 with a sample layer of the coating material 32. It will be appreciated by those skilled in the art that other appropriate techniques of coating the coating sample area 43 of the sensor body 42 with coating material 32, such as brushing, dipping, etc., are within the scope of the present invention. It should be noted that the coating sample area 43 of the sensor body 42 may be coated separately or simultaneously with coating of the heat exchanger core 16. In any event, the coating sample area 43 of the sensor body 42 is coated with the same coating material 32 as the core 16, and a thickness of the sample layer of the coating material 32 over the coating sample area 43 is the same as the thickness of the coating layer 32 over the heat exchanger core 16 in order to provide an equivalent sample of the coating on the heat exchanger core.

[0058] As further can be seen in FIGS. 1b and 2a, the insulator cover 48 of the sensor body 42 acts as a canopy cover that provides a coating spray protection during the coating process to the fastener member 54 keeping it free from the coating and insulated from the coating sample area 43, thus insuring that no electrical current flows through tubes and fins of the heat exchanger core 16.

[0059] The conductive terminals 45a and 45b of the sensor assembly 40 are connected to a sensing circuit 60, the exemplary embodiment of which is illustrated in FIG. 3. The purpose of sensing circuit 60 is to act as an interpreter between the coating wear sensor asseembly 40 and a coating condition diagnostic unit (not shown). The circuit 60 acts similar to a voltmeter, however, the circuit 60 is specifically adapted to function as part of a more advanced diagnostic system. The coating wear sensor asseembly 40, when connected to the sensing circuit 60, changes resistance as the coating material 32 in the coating sample area 43 of the sensor body 42 is removed or deteriorates. The sensing circuit is adapted for monitoring the electrical resistance change and is also adapted for providing an interpretive output which may take the form of a voltage output signal transmitted to the diagnostic unit. This output preferably is also conditioned within specific limits in order to protect the diagnostic unit itself.

[0060] The sensing circuit 60 is designed to provide a low power circuit such that arcing and stray current will be limited to the coating sample area 43 and prevent arcing across to the heat exchanger core 16. This-also insures the coating depletion conditions for the coating sample area 43 will be the same for the coating of the heat exchanger core 16. This also insures that the sensing circuit 60 will not affect the deterioration of the heat exchanger core 16 and more specifically the tubes 18 and fins 20.

[0061] Generally, the sensing circuit 60 includes a power input 62 from any appropriate source of an electrical power in the form of power leads for driving the circuit for converting first signals indicative of the resistance change in the sensor assembly 40 into a second signal recognizable to the diagnostic unit, such an electric storage batter (not shown), a sensor input 62 from the sensor assembly 40 in the form of sensor leads for receiving the first signals, and an output 66 connected to the coating condition diagnostic unit (not shown) (e.g., an on-board diagnostic unit or a remote unit) that analyses the electric signal from the sensing circuit 60 and determines the condition of the coating layer on the heat exchanger core. The output 66 may be in any appropriate form known to those skilled in the art, such as output connections or wireless transmitters for communicating the second signal to the diagnostic unit. In the latter case, the sensor output signal is remotely monitored by telemetric means, such as electromagnetic waves (e.g. radiofrequency, infrared, etc.). Alternatively, the function of the sensing circuit 60 may be performed using computer hardware, software or both instead of or in combination with the circuit 60.

[0062] Preferably, the sensing circuit 60 is fabricated onto a printed circuit board (PCB). The sensing circuit 60, especially in the form of the PCB, may be mounted directly to the coating wear sensor as a coating wear detecting module.

[0063] Moreover, the ID tag of the coating wear sensor assembly disclosed above may be in the form of an electronic signal provided as a part of the sensing circuit 60.

[0064] It will be appreciated by those skilled in the art that the specific components of the sensing circuit 60 may vary without departing from the scope of the present invention and any suitable structural configuration may be used.

[0065] FIGS. 4a-4c illustrate a second exemplary embodiment of the coating wear sensor assembly, generally depicted by reference numeral 140. The sensor assembly 140 comprises a cup-shaped body 142 and a threaded fastener shaft 152 coaxially extending from the cup-shaped body 142 for securing the sensor assembly 140 to the heat exchanger core 16. Preferably the cup-shaped body 142 has a bottom wall 142a and a substantially cylindrical sidewall 142b extending. It will be appreciated by those skilled in the art that, alternatively, the sidewall 142b of the cup-shaped body 142 may be substantially conical or of any other appropriate shape, such as oval. Preferably, the shaft 152 is formed integrally with the body 142 from an insulator material. In an assembled condition, the shaft 152 extends through and between the core fins 20 and is threaded into a retainer 156, thus firmly securing the sensor body 142 adjacent to the core 16 so that the core 16 is held in between the retainer 156 and the sensor body 142. Preferably, the retainer 156 is provided with a series of ribs adapted to firmly engage the tubes 18 of the heat exchanger core 16.

[0066] An inner peripheral surface of the sidewall 142b of the cup-shaped body 142 forms a coating sample area 143 that includes a pair of spaced electric electrodes 144a and 144b. The electrodes 144a and 144b are separated by a portion of the insulator material of the body 142, as illustrated in FIG. 4c. Each of the electrodes 144a and 144b is electrically connected to a conductive terminal (145a and 145b, respectively) to which an electrical wire harness assembly would be attached. The conductive terminals 145a and 145b of the sensor assembly 140 are connected to a signal processing circuit that is substantially similar to one disclosed with regard to the first exemplary embodiment of the coating wear sensor 40 and which is illustrated in FIG. 3.

[0067] Alternatively, an inner peripheral surface of the bottom wall 142a of the cup-shaped body 142 may form the coating sample area and include a pair of the spaced electric contacts. Yet alternatively, an outer peripheral surface of the cup-shaped body 142 or both inner and outer peripheral surfaces of the cup-shaped body 142 may form a coating sample area.

[0068] The bottom wall 142a of the cup-shaped body 142 may be provided with a plurality of air holes 147, as shown in FIG. 4b, adapted to enhance airflow across the coating sample area 143.

[0069] After the coating wear sensor assembly 140 is mounted to the heat exchanger core 16, the sensor body 142, including the inner peripheral surface of the sidewall 142b, is coated with the same coating material 32 as the heat exchanger core 16, thus providing a conductive bridge between the electrodes 144a and 144b. It should be noted that the coating sample area 143 of the sensor body 142 may be coated separately or simultaneously with coating of the heat exchanger core 16. In any event, the coating sample area 143 of the sensor body 142 is coated with the same coating material 32 as the core 16, and a thickness of the sample layer of the coating material 32 over the coating sample area 143 is the same as the thickness of the coating layer 32 over the heat exchanger core 16 in order to provide an equivalent sample of the coating on the heat exchanger core.

[0070] In this embodiment, the bottom wall 142a of the cup-shaped body 142 acts as a canopy area that provides coating spray protection during the coating process to the threaded shaft 152 for keeping it free from the coating, thus ensuring that the sensor assembly 140 is electrically insulated (or separated) from the heat exchanger core 16.

[0071] FIGS. 5a and 5b illustrate a third exemplary embodiment of the coating wear sensor assembly, generally depicted by reference numeral 240.

[0072] The sensor assembly 240 comprises a substantially rectangular box-shaped body 242 and a threaded fastener shaft 252 coaxially extending from the box-shaped body 242 for securing the sensor assembly 240 to the heat exchanger core 16. Preferably the box-shaped body 242 has a bottom wall 242a and a sidewall 242b extending having a substantially rectangular cross-section. It will be appreciated by those skilled in the art that, alternatively, the sidewall 242b of the box-shaped body 242 may be of substantially variable cross-section or be of any other appropriate shape.

[0073] Preferably, the shaft 252 is formed integrally with the body 242 from an electrically insulator material. In an assembled condition, the shaft 252 extends through and between the core fins 20 and is threaded into a retainer 256, thus firmly securing the sensor body 242 adjacent to the core 16 so that the core 16 is held in between the retainer 256 and the sensor body 242. Preferably, the retainer 256 is provided with a series of ribs adapted to firmly engage the tubes 18 of the heat exchanger core 16.

[0074] A front surface of the bottom wall 242a of the box-shaped body 242 forms a coating sample area 243 that includes a pair of spaced electric electrodes 244a and 244b. The electrodes 244a and 244b are separated by a portion of the insulator material of the body 242, as illustrated in FIG. 5b. Each of the electrodes 244a and 244b is electrically connected to a conductive terminal (not shown) to which an electrical wire harness assembly would be attached. The conductive terminals of the sensor assembly 240 are connected to a signal processing circuit that is substantially similar to one disclosed with regard to the first exemplary embodiment of the coating wear sensor 40 and which is illustrated in FIG. 3.

[0075] In this embodiment, a bottom wall of the box-shaped body 242 acts as a canopy area that provides coating spray protection during the coating process to the threaded shaft 252, thus keeping it free from the coating.

[0076] FIGS. 6a-6d illustrate a forth exemplary embodiment of the coating wear sensor assembly in accordance with the present invention, generally depicted by reference numeral 340. The coating wear sensor assembly 340 comprises a sensor body 342 and a fastener assembly 352 adapted to secure the sensor body 342 to the heat exchanger core 16. The sensor body 342 is substantially similar to the sensor body 42 of the sensor assembly 40 in accordance with the first exemplary embodiment of the present invention, shown in FIGS. 2a and 2b. The fastener assembly 352 includes a fastener sleeve 354 secured to the sensor body 342 and a separate push pin 356 in the form of a locking shaft that penetrates into the fastener sleeve 354 after the sensor body 342 is mounted to the heat exchanger core 16 by inserting the fastener sleeve 354 through the fins 20 and between the core tubes 18, as shown in FIGS. 6a and 6d. As the push pin 356 penetrates the fastener sleeve 354, the latter expands radially and engages adjacent fins 20 of the heat exchanger core 16, thus firmly securing the coating wear sensor assembly 340 to the heat exchanger core 16, as shown in the FIG. 6c. Preferably, the fastener sleeve 354 is manufactured integral with the sensor body 342.

[0077] The fastener sleeve 354 may have a plurality of barbs (not shown) integrally formed on an outer peripheral surface thereof so that when the push pin 356 penetrates and expands the fastener sleeve 354, the barbs engages adjacent fins 20 and/or tubes 18 of the heat exchanger core 16 and firmly lock the sensor assembly 340 to the heat exchanger core 16. Alternatively, the outer peripheral surface of the fastener sleeve 354 may be serrated.

[0078] It will be appreciated by those skilled in the art that the coating wear sensor assembly may be mounted adjacent to a front surface of the heat exchanger core 16 exposed to incoming airflow through the heat exchanger assembly 10, as well as adjacent to a rear surface of the heat exchanger core 16 exposed to the airflow leaving the heat exchanger assembly 10. In FIG. 7 is illustrated a vehicular heat exchanger module including an engine cooling radiator 70 and a condenser 80 of a vehicular air conditioning (A/C) system. Both a radiator core 72 and a condenser core 82 are coated with a layer of the catalytic coating composition 32. An electric coating wear sensor 40a is monted adjacent to a front surface of the heat exchanger core 72 exposed to incoming airflow through the radiator 70.

[0079] The foregoing description of the preferred embodiments of the present invention has been presented for the purpose of illustration in accordance with the provisions of the Patent Statutes. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. The embodiments disclosed hereinabove were chosen in order to best illustrate the principles of the present invention and its practical application to thereby enable those of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as suited to the particular use contemplated, as long as the principles described herein are followed. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains. Thus, changes can be made in the above-described invention without departing from the intent and scope thereof. It is also intended that the scope of the present invention be defined by the claims appended thereto.

Claims

1. A heat exchanger assembly comprising:

a heat exchanger including a first tank, a second tank and a heat exchanger core extending between the first tank and the second tank for providing a fluid communication therebetween;

said heat exchanger core coated with a coating layer of a coating material; and

an electronic coating wear sensor assembly for detecting a deterioration of said coating layer, said coating wear sensor assembly having at least one pair of spaced electrodes electrically insulated from each other by an insulating spacer,

a surface of said sensor assembly adjacent to said electrodes forms a coating sample area coated with a sample layer of said coating material, said sample layer of said coating material provides a conductive bridge between said electrodes;

said coating sample area of said coating wear sensor assembly is electrically insulated from said coating layer of said heat exchanger core.

2. The heat exchanger assembly as defined in claim 1, wherein said coating material is a catalytic coating composition provided for reducing airborne pollutant elements that pass through said heat exchanger core.

3. The heat exchanger assembly as defined in claim 1, wherein a thicness of said sample layer of said coating material on said coating sample area is substantially the same as a thicness of said coating layer of said coating material on said heat exchanger core.

4. The heat exchanger assembly as defined in claim 1, wherein said coating sample area of said coating wear sensor assembly is mounted adjacent to said heat exchanger core.

5. The heat exchanger assembly as defined in claim 1, wherein said coating wear sensor assembly is a resistance measuring sensor provided to measure an electrical resistance of said coating sample layer of said coating material.

6. The heat exchanger assembly as defined in claim 1, wherein said coating wear sensor assembly comprises a sensor body and a fastener assembly provided for securing said sensor body to said heat exchanger core, said sensor body includes said at least one pair of said spaced electrodes and defines said coating sample area, said fastener assembly includes a fastener member having a shaft extending through said heat exchanger core and a retainer secured to said shaft for clamping said core between said sensor body and said retainer.

7. The heat exchanger assembly as defined in claim 6, wherein said fastener member is formed integral with said sensor body.

8. The heat exchanger assembly as defined in claim 6, wherein said shaft of said fastener member has a threaded outer peripheral surface adapted to threadedly engage said retainer.

9. The heat exchanger assembly as defined in claim 6, wherein said threaded shaft of said fastener assembly is made of a heat conductive material and functions as a heat-conducting conduit that carries a thermal energy from said heat exchanger core to said coating sample area for substantially equalizing a temperature of said coating sample area with a temperature of said heat exchanger core.

10. The heat exchanger assembly as defined in claim 1, wherein said coating wear sensor assembly further including a heat-conducting conduit that carries a thermal energy from said heat exchanger core to said coating sample area for substantially eqilizing a temperature of said coating sample area with a temperature of said heat exchanger core.

11. The heat exchanger assembly as defined in claim 6, further including a canopy cover providing a coating spray protection during a coating process to said shaft of said fastener member keeping it free from said coating material and insulated from said coating sample area.

12. The heat exchanger assembly as defined in claim 6, wherein said sensor body of said electronic coating wear sensor assembly includes at least one pair of substantially disk-shaped electrodes separated by a substantially disk-shaped insulator spacer, and

wherein circumferentially outer peripheral surfaces of said electric electrodes and said insulator spacer form said coating sample surface.

13. The heat exchanger assembly as defined in claim 12, wherein said sensor body of said electronic coating wear sensor assembly further includes an insulator cover disposed between said sensor body and said heat exchanger core for electrically isolating said coating sample surface of said sensor assembly from said heat exchanger core and preventing stray current from passing through said heat exchanger core and functions as a canopy cover that provides a coating spray protection during a coating process to said shaft of said fastener member keeping it free from said coating material and insulated from said coating sample area.

14. The heat exchanger assembly as defined in claim 11, wherein said canopy cover is in the form of an insulator cover disposed between said sensor body and said heat exchanger core.

15. The heat exchanger assembly as defined in claim 6, wherein said sensor body of said electronic coating wear sensor assembly has a substantially cup-shaped body and a fastener shaft coaxially extending from said cup-shaped body for securing said sensor assembly to said heat exchanger core.

16. The heat exchanger assembly as defined in claim 15, wherein said fastener shaft is formed integrally with said cup-shaped body.

17. The heat exchanger assembly as defined in claim 6, wherein said sensor body of said electronic coating wear sensor assembly has a substantially box-shaped body and a fastener shaft coaxially extending from said box-shaped body for securing said sensor assembly to said heat exchanger core.

18. The heat exchanger assembly as defined in claim 17, wherein said fastener shaft is formed integrally with said cup-shaped body.

19. The heat exchanger assembly as defined in claim 6, wherein said sensor body of said electronic coating wear sensor assembly including a bottom wall and a sidewall extending from said bottom wall.

20. The heat exchanger assembly as defined in claim 19, wherein said coating sample area is formed on said bottom wall of said sensor body.

21. The heat exchanger assembly as defined in claim 19, wherein said coating sample area is formed on said sidewall of said sensor body.

22. The heat exchanger assembly as defined in claim 1, wherein said fastener assembly of said coating wear sensor assembly includes a fastener sleeve extending through said heat exchanger core and a push pin provided to penetrate into said fastener sleeve for radially expanding said fastener sleeve thereby firmly engaging said heat exchanger core and securing said coating wear sensor assembly thereto.

23. The heat exchanger assembly as defined in claim 1, wherein said coating wear sensor assembly further includes a sensing circuit provided for monitoring an electrical resistance change of said sample layer of said coating material on said coating sample area and for providing an interpretive output to a coating condition diagnostic unit.

24. The heat exchanger assembly as defined in claim 1, further including an ID tag provided to identify a date of applying said coating layer to said heat exchanger assembly and a composition of said coating material.