Substrate and filter with stress/strain detection and method of use

A catalytic converter includes a cylindrical catalyst substrate and a detection device monitoring the integrity of the catalyst substrate. The detection device monitoring the integrity of the catalyst substrate is a band formed on an outer circumference of the catalyst substrate.

FIELD

The present disclosure relates to catalytic converters and, specifically, a device and method for monitoring the integrity of a catalyst substrate within a catalytic converter.

BACKGROUND

Often, when a vehicle is brought into a dealer for a rattle or noise coming from a catalytic converter, a dealership technician will remove the catalytic converter and send it to the supplier for examination without determining whether the catalytic converter is actually malfunctioning or whether a catalyst substrate within the catalytic converter is damaged. Currently, there is no tool that assists the dealership technician in diagnosing the rattle or noise. The dealership technician simply warranties the parts and replaces the entire exhaust system and catalytic converter. Replacing the entire exhaust system and catalytic converter can be very expensive and lead to unnecessary increased warranty costs for the parent company. Thus, there is a need for an integrated device associated with the catalytic converter which can verify whether the catalyst substrate is compromised or cracked.

Additionally, during the design phase of the catalytic converter, the design engineer or test technician wraps pressure paper around the catalyst substrate and makes a guess at a pressure at which to test the catalyst substrate. When the part is removed from the pressure paper, the color of the paper tells only the maximum pressure applied to the catalyst substrate. The maximum pressure, or color of the paper, is determined based on visual inspection by the design engineer or test technician and is therefore subjective and could change from person to person. Further, the entire process of wrapping the catalyst substrate, applying the pressure, unwrapping the catalyst substrate, and visually inspecting the paper is time consuming. Thus, there is a need for a device that can accurately indicate the stress on a catalyst substrate in real time to quicken the matting strategy process and reduce the cost of materials.

SUMMARY

A catalytic converter includes a cylindrical catalyst substrate and a detection device monitoring the integrity of the catalyst substrate. The detection device monitoring the integrity of the catalyst substrate is a band formed on an outer circumference of the catalyst substrate.

The catalytic converter may further include a detection device that provides readings indicating stress or strain caused by expansion or compression of the catalyst substrate.

The catalytic converter may further include a detection device having a positive terminal, a negative terminal, and a wire connecting the positive terminal to the negative terminal. The detection device may be configured to provide a resistance measurement of a current flowing through the wire.

The catalytic converter may further include a plurality of detection devices that are disposed around the outer circumference of the catalyst substrate. A first of the plurality of detection devices may be disposed near a first end of the catalyst substrate. A second of the plurality of detection devices may be disposed in a center of the catalyst substrate. A third of the plurality of detection devices may be disposed near a second end of the catalyst substrate. Each of the plurality of detection devices provides a resistance measurement of a current flowing through the detection device.

The catalytic converter may further include a detection device that provides a resistance measurement indicating a temperature of the catalyst substrate at a location of the detection device on the catalyst substrate.

The catalytic converter may further include a detection device that is a strain gauge.

The catalytic converter may further include a detection device that is a single band of a plurality of strain gauges connected in series.

The catalytic converter may further include a detection device that is a single band of a plurality of strain gauges connected in parallel.

The catalytic converter may further include a detection device that is a band of conductive material connecting a positive end with a negative end and having an electrical current flowing therethrough.

The catalytic converter may further include a detection device that is embedded into or onto the catalyst substrate using three-dimensional printing.

The catalytic converter may further include a detection device that is circuit printed onto the catalyst substrate.

The catalytic converter may further include a detection device that is adhered onto the catalyst substrate.

A vehicle includes a catalyst substrate, a detection device, and a controller. The detection device is configured to provide a signal monitoring the integrity of the catalyst substrate. The controller receives the signal from the detection device and determines a stress or strain on the catalyst substrate or a fracture in the catalyst substrate. If the controller determines that there is a fracture in the catalyst substrate, the controller stores the time of the fracture and the stress or strain measurements and provides a signal indicating that the catalyst substrate has been compromised.

The vehicle may further include a detection device having a positive terminal, a negative terminal, and a conductive band connecting the positive terminal to the negative terminal. The detection device may be configured to provide a resistance measurement of a current flowing through the conductive band.

The vehicle may further include a controller that determines the stress or strain on the catalyst substrate from a resistance measurement of the current flowing through the conductive band and determines the fracture in the catalyst substrate from an interruption in current flowing through the conductive band.

A method for monitoring an integrity of a catalyst substrate includes providing a signal, by a detection device, indicating a resistance measurement of a current flowing through a circuit in the detection device; determining, by a controller or a device monitor, whether the circuit is complete; signaling, by the controller or the device monitor, a catalyst substrate failure if the circuit is not complete; and reporting, by the controller or the device monitor, a stress or strain measurement and a time for the catalyst substrate failure if the circuit is not complete.

The method may further include use of a detection device that is disposed around an outer circumference of the catalyst substrate.

The method may further include connecting the device monitor to the detection device; wrapping the catalyst substrate with a mat insulation; placing the catalyst substrate and mat insulation within a canning sleeve; and placing the canning sleeve under a first reduced diameter or a first stress level. The device monitor may determine whether the circuit is complete after the canning sleeve is placed under the first reduced diameter or the first stress level.

The method may further include reporting, by the device monitor, a stress or strain measurement for the catalyst substrate failure if the device monitor determines that the circuit in the detection device is complete; and placing the canning sleeve under an increased reduced diameter or an increased first stress level if the device monitor determines that the circuit in the detection device is complete.

The method may further include continuing to provide a signal, by the detection device, indicating the resistance measurement of the current flowing through the circuit in the detection device if the controller determines that the circuit in the detection device is complete.

DETAILED DESCRIPTION

The present teachings advantageously provide a device and method for determining an appropriate canning pressure for a catalytic canister during the design process and for monitoring catalyst canisters in an exhaust system of a vehicle. The stress/strain detection device and method will assist a dealership technician in diagnosing rattles, noises, and failures in the exhaust system and will decrease warranty costs seen by the parent company for unnecessarily warrantying exhaust systems and catalytic converters. Further, the stress/strain detection device and method will assist the design engineer in the investigation of the type and quantity of matting material to wrap around a catalyst converter and will decrease the test time and material cost by eliminating the need for pressure paper during the process.

With reference toFIG. 1, a vehicle10including a stress/strain detection device70(FIGS. 3A-6) and system12according to the present teachings is illustrated. Although the vehicle10is illustrated as an automobile inFIG. 1, the present teachings apply to any other suitable vehicle, such as a sport utility vehicle (SUV), a mass transit vehicle (such as a bus), or a military vehicle, as examples. The vehicle10further includes an engine14having an exhaust manifold18out of which one or more exhaust pipes22extend and a controller, or control module,24controlling the functions of the engine14. A catalytic converter, or catalyst,26and a muffler30may be disposed along each of the one or more exhaust pipes22. Additional exhaust parts34such as a resonator, a performance mid-pipe muffler, a diesel oxidation catalyst, or a particulate filter (depending on the type of vehicle) may also be disposed along the exhaust pipe22.

The catalytic converter26reduces the toxicity of emissions from the engine14. The catalytic converter26may be a three-way catalytic converter, a two-way catalytic converter, an oxidation catalyst, an NOx adsorber catalyst, a diesel particulate filter, a diesel oxidation catalyst, or any other type of catalytic converter. A three-way catalytic converter performs three simultaneous tasks: (1) reduction of nitrogen oxides to nitrogen and oxygen (2NOX→xO2+N), (2) oxidation of carbon monoxide to carbon dioxide (2CO+O2→2CO2), and (3) oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water

(CX⁢H2⁢X+2+[3⁢x+12]⁢O2->x⁢⁢CO2+(x+1)⁢H2⁢O).
A two-way catalytic converter performs two simultaneous tasks: (1) oxidation of carbon monoxide to carbon dioxide (2CO+O2→2CO2), and (2) oxidation of un-burnt and partially-burnt hydrocarbons (HC) to carbon dioxide and water

(CX⁢H2⁢X+2+[3⁢x+12]⁢O2->x⁢⁢CO2+(x+1)⁢H2⁢O).
An oxidation catalyst converts carbon monoxide and hydrocarbons to carbon dioxide and water

(2⁢CO+O2->2⁢CO2⁢⁢and⁢⁢CX⁢H2⁢X+2+[3⁢x+12]⁢O2->x⁢⁢CO2+(x+1)⁢H2⁢O).
A NOx adsorber catalyst reduces NOx to N2 and eliminates stored NOx in the system (2NOX→xO2+N). A diesel particulate filter filters diesel particulate matter (small solid particles resulting from the burning of diesel fuel containing soot, hydrocarbons, ashes, and sulphuric acid) and is periodically regenerated to burn off the particulate matter. A diesel oxidation catalyst operates as an oxidation catalyst to reduce CO and HC

(2⁢CO+O2->2⁢CO2⁢⁢and⁢⁢CX⁢H2⁢X+2+[3⁢x+12]⁢O2->x⁢⁢CO2+(x+1)⁢H2⁢O)
and destroy the organic fraction of the diesel particulate matter.

Referring additionally toFIG. 2, the catalytic converter26includes a catalyst canister body, or catalytic converter body,38disposed within a heat shield42. The catalyst canister body38may be formed from stainless steel. A catalyst substrate, or monolith,46is wrapped with mat insulation packing50within the catalyst canister body38. The catalyst substrate46may be a cylindrical substrate or a substrate with an elliptical cross-section. The catalyst substrate46may further have a honeycomb structure and be formed from cordierite, silicon carbide, a metal, cerium (Ce), ceramic, stainless steel, or any other appropriate material. The catalyst substrate46is coated with a thin layer of catalyst, being active material such as alumina oxide, cerum oxide, and rare earth stabilizer metals such as platinum (Pt), palladium (Pd), and rhodium (Rh). In other embodiments, gold (Au), cerium (Ce), iron (Fe), manganese (Mn), and nickel (Ni) may also be used. The mat insulation packing50insulates, seals, and provides an enclosure for the catalyst substrate46. The structure and density of the mat insulation packing50determines the amount of insulation, sealing, and support the mat insulation packing50provides for the catalyst substrate46. Examples of structures of the mat insulation packing50are intumescent/non-intumescent matting, ceramic fiber, wire mesh, fiber glass, or any other material that both insulates and provides support for the catalyst substrate.

During use of the catalytic converter26, exhaust gas including hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxide (NOx) enters a front end54of the catalytic converter26at the arrow58. As the exhaust gas passes through the honeycomb structure of the catalyst substrate46a chemical reaction occurs between the hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxide (NOx) in the exhaust gas and the catalytic active material to reduce and/or oxidize the harmful gasses as previously described. Tail pipe emissions including water (H20), carbon dioxide (CO2), and nitrogen (N2) then exit the catalytic converter26at a rear end62at arrow66.

Now referring toFIGS. 3A and 3B, the stress/strain detection device70may be disposed on the catalyst substrate46to measure stress or strain caused by expansion or compression of the catalyst substrate46and perform continuous monitoring of the catalyst substrate46when the catalyst substrate46is installed in the vehicle10. In some embodiments, the stress/strain detection device70may be a strain gauge disposed in a band around an external surface74of the catalyst substrate46. A strain gauge is a sensor whose resistance varies with applied force. The strain gauge converts force, pressure, tension, weight, etc., into a change in electrical resistance which can be measured (further described below). Although a strain gauge is discussed in the present teachings, any conductive material that would be severed in the event of a fracture of the catalyst substrate46may be used.

The stress/strain detection device70may include a positive terminal78and a negative terminal82with a wire86disposed therebetween. While the wire86is illustrated as being disposed in a zig-zag or sinusoidal pattern, the wire may be disposed in a square wave, a straight band or any other pattern around the external surface74of the catalyst substrate46.

In some embodiments, as shown inFIG. 3A, the stress/strain detection device70may be formed as a single continuous band90of wire86around the external surface74of the catalyst substrate46. In other embodiments, as shown inFIG. 3B, the stress/strain detection device70may be comprised of a series of multiple stress/strain detection devices94connected in series or parallel.

The stress/strain detection device70may be printed onto, embedded into, or embedded onto the catalyst substrate46. Three-dimensional (3D) printing technology or circuit printing may be used to fix the stress/strain detection device70onto the external surface74or within the external surface74of the catalyst substrate46. Additionally, the stress/strain detection device70may be applied or adhered onto the external surface74of the catalyst substrate46by an adhesive. Thus, new catalyst substrates46may be manufactured with the stress/strain detection device70and pre-existing catalyst substrates46may be retrofitted with the stress/strain detection device70.

Now referring toFIG. 4A, during design, the catalyst substrate46is compressed to help determine the type and amount of mat insulation packing50necessary for the catalytic converter26. During use, the catalyst substrate46may be subjected to compressive forces due to temperature increase. During production, the catalyst substrate46may be subjected to compressive forces applied to the converter body38and mat insulation packaging50to retain the catalyst substrate46in an assembly position. When the catalyst substrate46is compressed, or when compressive forces act on the exterior surface74of the catalyst substrate46(shown by arrows98), the wire86between terminals78,82of the stress/strain detection device70thickens or increases in diameter, causing a lower resistance condition. The thickening of the wire86decreases the resistance to electrical current that flows from the positive terminal78to the negative terminal82through the wire86. The strain on the catalyst substrate46is measured by the resistance decrease. For example, the ratio of relative change in electrical resistance R to the mechanical strain c, or gauge factor (strain factor), may be calculated as:

GF=Δ⁢⁢RRɛ=Δ⁢⁢ρρɛ+1+2⁢v
where ε is mechanical strain which is equal to ΔL/L0, ΔL is the absolute change in length, L0is the original length, v is Poisson's ratio, Δρ is change in resistivity, ρ is unstrained resistivity, ΔR is change in strain gauge resistance, and R is unstrained resistance of strain gauge.

Referring toFIG. 4B, during design, the catalyst substrate46may also be subjected to expansive forces to help determine the type and amount of mat insulation packing50necessary for the catalytic converter26. During use, the catalyst substrate46may be subjected to expansive forces due to temperature decrease. When the catalyst substrate46expands, or when expansive forces act on the catalyst substrate46(shown by arrows102), the wire86between terminals78,82of the stress/strain detection device70thins or decreases in diameter, causing a high resistance condition. The thinning of the wire86increases the resistance to the electrical current that flows from the positive terminal78to the negative terminal82through the wire86. The strain on the catalyst substrate46is measured by the resistance increase. For example, the gauge factor (strain factor) equation, previously described, may be used to calculate the strain on the catalyst substrate46.

Referring toFIG. 4C, and in light of the descriptions ofFIGS. 4A and 4B, when a catalyst substrate46is subjected to either compressive or expansive forces98,102in excess, the catalyst substrate46will become compromised by a fracture or failure. For example, a failure due to excessive compressive force98on the catalyst substrate46is illustrated inFIG. 4C. The threshold at which the catalyst substrate46is compromised may depend on the material, structure, and dimensions of the substrate and external factors such as temperature.

During a failure, the catalyst substrate46cracks or separates as shown by a fracture106inFIG. 4C. The fracture106penetrates through the wire86of the stress/strain detection device70, separating the wire86and causing a break in the electrical current flowing from the positive terminal78to the negative terminal82. Although the fracture106is illustrated as a result of excessive compressive force98inFIG. 4C, the same result will occur with an excess in the expansive forces102(FIG. 4B) previously discussed.

Now referring toFIG. 5, multiple stress/strain detection devices70a,70b,70cmay be disposed on the catalyst substrate46. While three stress/strain detection devices70a,70b,70care illustrated and discussed, it is understood that any number of stress/strain detection devices may be used and placed in any location on the catalyst substrate46. Multiple bands of the stress/strain device70a,70b,70cdetermine and monitor the temperature and thermal behavior of the catalyst substrate46in real time by providing the differences in strain between the multiple stress/strain devices70a,70b,70c. By placing a stress/strain detection device70aat a first end, a stress/strain detection device70bat a center, and a stress/strain detection device70cat a second end, a catalyst temperature or temperature behavior of the catalyst substrate46may be monitored. The temperature at each location, or the thermal behavior of the catalyst substrate46, can be monitored by catalyst thermal expansion (i.e., expansive forces102) or compression (i.e., compressive forces98).

For example, hot exhaust gas, or heat, flows through the catalyst substrate46as indicated at arrow110. The resistance of current through the circuit in each of the stress/strain detection devices70a,70b,70c, can determine the temperature at the respective locations of the stress/strain detection devices70a,70b,70c. For example, as the temperature of the catalyst substrate46increases, the catalyst substrate46undergoes thermal expansion (similar to the illustration inFIG. 4B). Thus, the wire86between terminals78,82of the stress/strain detection device70thins or decreases in diameter, causing a high resistance condition. The thinning of the wire86increases the resistance to the electrical current that flows from the positive terminal78to the negative terminal82through the wire86. The strain (and therefore the temperature) on the catalyst substrate46is measured by the resistance increase (using the gauge factor/strain factor equation previously described). The higher the temperature of the catalyst substrate46, the thinner the wire86between terminals78,82.

Using the stress/strain detection devices70a,70b,70cto determine the temperatures at various locations on the catalyst substrate46is beneficial for determining how quickly the catalyst substrate46heats up from front to rear during vehicle10start-up. Knowing the time for the catalyst substrate46to heat up effects the catalyst light off duration and vehicle emissions at start-up. Further, temperature differences in the stress/strain detection devices70a,70b,70ccould indicate the location of one or more cracks in the catalyst substrate46.

By utilizing the configurations described in relation toFIGS. 3A-5, the catalyst substrate46may be continuously monitored. Continuous monitoring of the catalyst substrate is very beneficial in verifying the integrity of the catalyst substrate, troubleshooting issues with the catalyst substrate, and monitoring temperatures of the catalyst substrate. Continuous monitoring of the catalyst substrate46provides engine conditions at the exact point of a catalyst substrate46failure which can be used to diagnose other issues in the vehicle10system. The stress/strain detection device70will provide the time of the failure and the stress and/or strain (and thus temperature) on the catalyst substrate46at the time of the failure. The time of the failure may then be used to gather specific engine (and other) data.

Continuous monitoring of the catalyst substrate46further provides an indication of how the catalyst substrate46is handling extreme cold starts (for example only, less than or equal to 30 degrees Celsius). As previously stated, using multiple stress/strain detection devices70a,70b,70cto monitor (and record) the temperatures at various locations on the catalyst substrate46is beneficial for determining how quickly the catalyst substrate46heats up from front to rear at start-up, which effects the catalyst light off duration and vehicle emissions at start-up. The conditions for catalyst light off and performing vehicle emissions diagnostics during extreme cold starts can be stressful on the catalyst substrate46. Therefore, continuous monitoring of the catalyst substrate46can provide a constant check on the integrity of the catalyst substrate46.

With reference toFIG. 6, a block diagram of the stress/strain detection system12according to the present teachings for the stress/strain detection device70is shown. The stress/strain detection device70communicates with a stress/strain detection device monitor114in the control module24in the vehicle10. The stress/strain detection device monitor114receives signals from the stress/strain detection device70indicating a resistance on the current flowing through the wire86connecting the positive terminal78with the negative terminal82. The stress/strain detection device monitor114also receives signals from the stress/strain detection device70indicating an interruption of flow in the electrical current.

The stress/strain detection device monitor114uses the data received from the stress/strain detection device70to determine a stress or strain on the catalyst substrate46, a temperature of the catalyst substrate46in the one or more locations of the stress/strain detection device70, and whether a failure has occurred in the catalyst substrate46. The stress/strain detection device monitor114may utilize the gauge factor (strain factor) equation, as previously discussed, to determine the stress or strain on the catalyst substrate46. The stress/strain detection device monitor114may determine the temperature of the catalyst substrate46at the location of the stress/strain detection device70by the resistance (due to heat) in the wire86of the stress/strain detection device70, and the stress/strain detection device monitor114may determine that a failure has occurred in the catalyst substrate46if the stress/strain detection device70provides a signal indicating an interruption of flow in the electrical current.

The stress/strain detection device monitor114may further communicate with a control area network (CAN)118and/or a driver interface console (DIC)122to communicate data and/or issues with a driver or technician. The stress/strain detection device monitor114may record and store stress/strain measurements on the catalyst substrate46and temperatures of the catalyst substrate46for retrieval by the technician through the CAN118. If the stress/strain detection device monitor114determines that a failure has occurred in the catalyst substrate46, the stress/strain detection device monitor114may communicate with the DIC122to communicate the failure to the driver. The failure may be communicated through a light or sound, for example by illuminating a check engine light and/or sounding an alarm. The stress/strain detection device monitor114may also identify and store the catalyst substrate46conditions at the time of failure for communication to the technician through the CAN118.

Now referring toFIG. 7, a flowchart for a method200is shown. The method200is configured to investigate a canning pressure for the catalyst substrate46using the stress/strain detection device70. The method200can be performed by a user or test administrator in combination with the stress/strain detection device70and a computer or monitoring device. The method200starts at204.

At208, at least one stress/strain detection device70(70a,70b,70c) on the catalyst substrate46is connected to a computer or other monitoring device to collect real time data from the stress/strain detection device70. The computer or other monitoring device performs the same functions as the stress/strain detection device monitor114in the control module24in the vehicle10. For example, the computer or monitoring device receives signals from the stress/strain detection device70indicating a resistance on the current flowing through the wire86connecting the positive terminal78with the negative terminal82and indicating an interruption of flow in the electrical current. The computer or monitoring device then uses the data received from the stress/strain detection device70to determine a stress or strain on the catalyst substrate46, a temperature of the catalyst substrate46in the one or more locations of the stress/strain detection device70, and whether a failure has occurred in the catalyst substrate46.

At212, the catalyst substrate46is wrapped with the mat insulation packaging50and placed in a canning metal sleeve, or catalyst canister body38. The monitoring device begins receiving signals and/or readings from the stress/strain detection device70to begin monitoring or measuring the catalyst substrate46at216. At220, the canning metal sleeve, or catalyst canister body38, is placed under a first reduced diameter or a first stress level. An example of a first reduced diameter is a reduction in diameter of the canning metal sleeve (or catalyst canister body38) by a range of 0.1 to 10.0 percent (%). An example of a first stress level is within the range of 0.5 and 2.0 megapascals (MPa). Please note that the first reduced diameter and the first stress level may be any value that either reduces the diameter of, or applies stress to, the canning metal sleeve (or catalyst canister body38) and may be set by the manufacturer and may vary from part to part or manufacturer to manufacturer.

At224, the method200determines whether the stress/strain detection device70circuit is still complete. The stress/strain detection device70circuit is the electric circuit extending along the wire or conductive band86from the positive terminal78to the negative terminal82. If the stress/strain detection device70circuit (or wire86) has been compromised, the stress/strain detection device70will send a signal to the computer or monitoring device indicating an interruption of flow in the electrical current. If the stress/strain detection device70has not been compromised, the stress/strain detection device70will continue sending signals and/or readings indicating a resistance on the current flowing through the wire86connecting the positive terminal78with the negative terminal82(as in216).

If the stress/strain detection device70circuit has been compromised at224, a substrate failure is signaled by the computer or monitoring device at228. This is similar to the stress/strain detection device monitor114communicating with the DIC122to communicate the failure to the driver, as previously described. At232, the stress/strain level during the failure is reported by the computer or monitoring device and the method ends at236.

If the stress/strain detection device70continues to send signals and/or readings indicating a resistance on the current flowing through the wire86connecting the positive terminal78with the negative terminal82at224(indicating that the stress/strain detection device circuit is still complete), the stress/strain level measurement is reported by the computer or monitoring device at240. The canning metal sleeve (or catalyst canister body38) is then placed under an increased reduced diameter or an increased stress level at244. An example of the increased reduced diameter is an additional reduction in diameter of the canning metal sleeve (or catalyst canister body38) by a range of 0.1 to 10.0 percent (%). An example of the increased stress level is an increase in the stress level within the range of 0.5 to 2.0 megapascals (MPa). Please note that the increased reduced diameter and the increased stress level may be any value that either further reduces the diameter of, or applies additional stress to, the canning metal sleeve (or catalyst canister body38) and may be set by the manufacturer and may vary from part to part or manufacturer to manufacturer. The method200then returns to224to determine whether the stress/strain detection device70circuit is complete. The method continues the cycle of224,240,244until the stress/strain detection device70circuit is no longer complete at224and a substrate failure is signaled at228. The stress/strain level during the failure is then reported by the computer or monitoring device at232and the method ends at236.

The method200is beneficial for determining the type, material, and amount of mat insulation packaging necessary for the catalytic converter26during the design process. Additionally, the method200determines the expansion of the catalyst substrate46under differing loads and stress levels. Use of the stress/strain detection device70eliminates the need to use wrap pressure paper and, thus, improves the accuracy of the test results. When using wrap pressure paper, the test administrator determines the maximum pressure during the test by visual inspection of the wrap pressure paper, leading to variation between test administrators and less reliable results. The stress/strain detection device70provides real time, accurate, stress/strain data, an exact time of failure, and exact data at the time of failure. Further, use of the stress/strain detection device70reduces test time (because visual inspection of wrap pressure paper is not required) and reduces costs of design and development of the catalytic converter26(reduction of test time and materials).

Now referring toFIG. 8, a flowchart for a method300is shown. The method300is configured to utilize the stress/strain detection device70to monitor the catalyst substrate46within the catalytic converter26in the vehicle10. The method300can be performed using the stress/strain detection device70and the stress/strain detection system12including the controller24, the CAN118, and the DIC122. The method300starts at304.

At308, the stress/strain detection device70begins sending signals and/or readings to the stress/strain detection device monitor114such that the stress/strain detection device monitor114monitors the integrity of the catalyst substrate46and records measurements of stress and/or strain on the catalyst substrate46. For example, the stress/strain detection device monitor114receives signals from the stress/strain detection device70indicating a resistance on the current flowing through the wire86connecting the positive terminal78with the negative terminal82and indicating an interruption of flow in the electrical current. The stress/strain detection device monitor114then uses the data received from the stress/strain detection device70to determine a stress or strain on the catalyst substrate46, a temperature of the catalyst substrate46in the one or more locations of the stress/strain detection device70, and whether a failure has occurred in the catalyst substrate46.

At312, the stress/strain detection device monitor114determines whether the wire86connecting the positive terminal78with the negative terminal82in the stress/strain detection device70is complete. If the stress/strain detection device70circuit (or wire86) has been compromised, the stress/strain detection device70will send a signal to the stress/strain detection device monitor114indicating an interruption of flow in the electrical current. If the stress/strain detection device70has not been compromised, the stress/strain detection device70will continue sending signals and/or readings indicating a resistance on the current flowing through the wire86connecting the positive terminal78with the negative terminal82.

If the wire86connecting the positive terminal78with the negative terminal82in the stress/strain detection device70is complete at312, the method300takes no action and continues monitoring the stress/strain detection device70at316. The stress/strain detection device monitor114continues the cycle of monitoring the stress/strain detection device70(at316) and determining whether the wire86connecting the positive terminal78with the negative terminal82in the stress/strain detection device70is complete (at312) until the stress/strain detection device monitor114determines that the wire86is fractured and the stress/strain detection device70circuit is broken.

If the wire86connecting the positive terminal78with the negative terminal82in the stress/strain detection device70is not complete at312, a catalyst substrate46failure is signaled at320. If the stress/strain detection device monitor114determines that a failure has occurred in the catalyst substrate46(i.e., the wire86connecting the positive terminal78with the negative terminal82in the stress/strain detection device70is fractured or not complete), the stress/strain detection device monitor114may signal the catalyst substrate46failure by communicating with the DIC122. The failure may be communicated to the driver or technician through a light or sound, such as illuminating a check engine light and/or sounding an alarm.

At324, the stress/strain detection device monitor114reports the stress/strain level at the time of failure. The stress/strain detection device monitor114also identifies and stores the catalyst substrate46conditions at the time of failure for communication to the technician through the CAN118. The method300then ends at328.

The method300is beneficial for monitoring the integrity of the catalyst substrate46within the catalytic converter26. Often, when a driver or technician identifies a rattle or other noise coming from the catalytic converter26, the technician will remove and replace the catalytic converter26and send the replaced catalytic converter26back to the supplier for examination. Technicians have no way of determining issues within the catalytic converter26without cutting out and physically examining the catalyst substrate46. Often, there is no issue with the catalyst substrate46and, thus, the cost and time associated with the removal and replacement of the catalytic converter26was unnecessary.

Use of the stress/strain detection device70and system12provides the technician with data indicating the integrity of the catalyst substrate46such that the technician does not need to invest the time in replacing the catalytic converter26if the catalyst substrate46is not compromised. Further, warranty costs are reduced by not removing and replacing catalytic converters26that are not damaged. Additionally, if there is a failure with the catalyst substrate46, the stress/strain detection device70and system12provide data at the exact time of the failure such that the technician can determine if there is a bigger issue in the exhaust system.

In this way, the present teachings advantageously provide a device, system, and methods to detect stress and/or strain on the catalyst substrate46, leading to reduced costs in both design and production, more accurate measurements, and a better catalytic converter26.