JP2012068230A - Crack occurrence detecting device for catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crack occurrence detecting device for detecting crack occurrence of a catalyst which can be in a high temperature state by the AE method.SOLUTION: A crack occurrence detecting device 101 comprises; an AE sensor 3 for detecting an AE wave; a heat shield plate 13 positioned between the AE sensor 3 and a catalyst 1 for partitioning; a guide shaft 6 one end 6a of which contacts the catalyst 1 through the heat shield plate 13, the other end 6b of which contacts the AE sensor 3, and which can transmit the AE wave from one end 6a to the other end 6b; and a coil spring 12 for energizing the guide shaft 6 to press one end 6a of the guide shaft 6 against the catalyst 1.

Description

  The present invention relates to a crack occurrence detection device that detects the occurrence of cracks in a catalyst using an acoustic emission (hereinafter referred to as AE) method.

  An internal combustion engine mounted on an automobile or the like is provided with an exhaust purification device that purifies exhaust gas. A diesel engine which is an example of an internal combustion engine has, for example, a monolith catalyst or the like for purifying harmful components (CO, HC, NOx, etc.) of exhaust gas, and a particulate fuel whose main purpose is to capture particulates contained in the exhaust gas. A curate filter (Diesel Particulate Filter; hereinafter referred to as DPF) and the like are provided.

  Conventionally, an abnormality detection device that detects an abnormality of an exhaust purification device is known. Patent Documents 1 and 2 disclose an abnormality detection device for the purpose of detecting clogging of a DPF, cracks in piping, and the like in an exhaust gas purification device for an internal combustion engine provided with a DPF. In the abnormality detection devices disclosed in Patent Documents 1 and 2, the pressure difference of the exhaust gas between the inlet side and the outlet side of the DPF is measured, and an abnormality is detected based on the pressure difference.

  The captured fine particles accumulate on the DPF. When the DPF is clogged, the pressure difference becomes large. Therefore, clogging of the DPF can be easily detected by measuring the pressure difference. Also, when the pipe is cracked, the pressure difference changes greatly. Therefore, it is possible to easily detect a crack in the pipe by measuring the pressure difference.

  However, when a crack occurs in the monolith catalyst, the pressure difference does not change so much unless the crack is large-scale. Therefore, it is difficult to detect cracks in the catalyst by the method based on the pressure difference. Conventionally, in order to detect the occurrence of cracks, it has been necessary to remove the catalyst from the apparatus and observe its appearance, or to cut a part as necessary and observe the inside.

  The present inventor has considered to detect the occurrence of cracks in the catalyst by applying the AE method so that the occurrence of cracks can be detected without removing the catalyst from the apparatus. Patent Documents 3 and 4 disclose techniques related to the AE method.

JP 2008-157200 A JP 2005-226519 A Japanese Patent Laid-Open No. 01-161146 Japanese Patent Laid-Open No. 08-062337

  When a crack occurs, elastic strain energy is released and an elastic wave is generated. In the AE method, the occurrence of a crack is detected by attaching a sensor to an object to be detected and detecting elastic waves with this sensor.

  However, since the catalyst disposed in the exhaust passage of the internal combustion engine is exposed to the exhaust gas, it is at a high temperature. Therefore, it is difficult to attach the sensor directly to the catalyst. The inventor of the present application considered providing a guide capable of transmitting an elastic wave, that is, a waveguide, between the catalyst and the sensor. However, it has been found that it is difficult to detect a crack in the catalyst satisfactorily by simply interposing a waveguide between the catalyst and the sensor.

  Then, an object of this invention is to provide the crack generation | occurrence | production detection apparatus which detects generation | occurrence | production of the crack of the catalyst which may be in a high temperature state by AE method.

  A catalyst crack occurrence detection device according to the present invention is a crack occurrence detection device that detects the occurrence of a crack in a catalyst that purifies exhaust gas, and includes an AE sensor that detects an AE wave, the AE sensor, and the catalyst. A partition member that divides the space, and is arranged so that one end contacts the catalyst and the other end contacts the AE sensor through the partition member, and AE waves can be transmitted from the one end to the other end. A guide shaft; and a biasing member that biases the guide shaft so as to press one end of the guide shaft against the catalyst.

  According to the crack occurrence detection device, the guide shaft is interposed between the AE sensor and the catalyst, and the AE sensor and the catalyst are partitioned by the partition member. Therefore, even if the catalyst is in a high temperature state, the AE sensor is prevented from being heated to the high temperature state by the catalyst. The guide shaft is pressed against the catalyst by the urging member. Therefore, the contact state between the guide shaft and the catalyst becomes good, and the AE wave generated in the catalyst with the occurrence of cracks is transmitted to the guide shaft satisfactorily. Therefore, although the AE sensor is arranged so as not to be easily affected by the heat from the catalyst, it is possible to accurately detect a crack in the catalyst.

  In a preferred aspect of the catalyst crack occurrence detection device disclosed herein, a holder having a through hole through which the guide shaft is inserted is provided. Support portions for supporting the guide shaft in the radial direction are provided at one end side and the other end side of the intermediate position in the longitudinal direction of the holder. The biasing member is constituted by a spring having one end engaged with the guide shaft and the other end engaged with the holder.

  Thus, the guide shaft is supported by the holder at one end side and the other end side in the longitudinal direction. Therefore, the guide shaft is stably supported. Therefore, the occurrence of cracks in the catalyst can be detected more accurately.

  In another preferable aspect, the support portion on the other end side of the holder has an elastic body that is elastically deformable at least in the radial direction of the guide shaft.

  As a result, even if the guide shaft is bent and deformed, the elastic body is elastically deformed in the radial direction of the guide shaft, thereby suppressing the occurrence of backlash between the guide shaft and the support portion. It is supported stably.

  In another preferable aspect, the support portion is configured by a cylindrical member in which an insertion hole through which the guide shaft is inserted is formed. A coating layer made of a material having a lower frictional resistance than that of the cylindrical member is formed on the inner peripheral surface of the cylindrical member.

  Thereby, even if the clearance (interval) between the guide shaft and the support portion is set to a minimum, the axial movement of the guide shaft can be maintained in a suitable state. As a result, it is possible to suppress the generation of a secondary AE signal caused by the contact between the support portion and the guide shaft, and it is easy to keep the pressing force of the guide shaft against the catalyst constant.

  In another preferable aspect, the end surface of the one end side of the guide shaft is formed in a curved surface shape.

  As a result, the catalyst is prevented from being scraped by the guide shaft as compared with the case where the end surface of the guide shaft is sharp. Therefore, the contact state between the catalyst and the guide shaft is kept better.

  In another preferred embodiment, the portion on the one end side of the holder is attached to a case that houses the catalyst. The crack occurrence detection device further includes a heat insulating material interposed between the holder and the catalyst.

  This suppresses the holder from receiving a heat from the catalyst and becoming a high temperature state. Therefore, it can suppress that an AE sensor is heated via a holder, and can suppress that an AE sensor will be in a high temperature state.

  In another preferred embodiment, a determination unit that determines whether or not a predetermined state is set in advance, and a detection that starts detecting the occurrence of cracks in the catalyst when the determination unit determines that the predetermined state is in the predetermined state. And a computer having a starter.

  For example, in one aspect, the catalyst is disposed in an exhaust passage of an internal combustion engine, and the predetermined state is a state in which fuel injection of the internal combustion engine is stopped.

  When fuel injection is stopped in an internal combustion engine, the temperature of the catalyst rapidly decreases, and cracks are likely to occur in the catalyst. In the crack occurrence detection device, a state in which the fuel injection is stopped is set as a predetermined state for starting detection of a crack. As a result, detection is performed in a state in which cracks are likely to occur, so that useless detection can be omitted and efficient detection can be performed.

  In another aspect, the catalyst is disposed in an exhaust passage of the internal combustion engine, and the predetermined state is a predetermined amount of decrease in the opening of an accelerator that adjusts the rotational speed of the internal combustion engine. It is in a state of exceeding the standard value.

  When the accelerator opening is suddenly reduced, the temperature of the catalyst is drastically lowered and cracks are likely to occur in the catalyst. In the crack occurrence detection device, as a predetermined state for starting the detection of cracks, a state in which the amount of decrease in the accelerator opening within a predetermined time exceeds a predetermined reference value (a state in which the accelerator opening decreases rapidly) ) Is set. As a result, detection is performed in a state in which cracks are likely to occur, so that useless detection can be omitted and efficient detection can be performed.

  In another aspect, the catalyst is provided with one or more temperature sensors, and the predetermined state is a decrease amount of the estimated temperature of the catalyst obtained from the temperature sensor within a predetermined time. It is in a state where it exceeds a predetermined reference value.

  As described above, when the temperature of the catalyst rapidly decreases, cracks are likely to occur in the catalyst. In the crack occurrence detection device, a state in which the amount of decrease in the catalyst temperature within a predetermined time exceeds a predetermined reference value (a state in which the temperature of the catalyst has suddenly decreased) is set as a predetermined state for starting crack detection. is doing. As a result, detection is performed in a state in which cracks are likely to occur, so that useless detection can be omitted and efficient detection can be performed.

  In another preferable aspect, the apparatus includes a determination device that determines whether or not a crack is generated in the catalyst based on a characteristic value included in the AE wave.

  For example, in one aspect, the determination apparatus measures the hit number of the AE wave as a characteristic value included in the AE wave. When the hit number exceeds a predetermined reference value, it is determined that a crack has occurred in the catalyst.

  The AE signal obtained by converting the AE wave into a signal is a waveform signal. Of these waveform signals, a signal having an intensity exceeding a predetermined threshold is referred to as a “hit”. The “number of hits” is a characteristic value indicating the number of hits recorded in a predetermined unit time. This number of hits tends to increase due to cracking in the catalyst. That is, by determining the presence or absence of cracks based on the number of hits, the cracks in the catalyst can be detected more accurately.

  In another aspect, the determination device calculates the energy of the AE wave as a characteristic value included in the AE wave. Then, when the energy exceeds a predetermined predetermined reference value, it is determined that a crack has occurred in the catalyst.

  The energy of the AE wave is a characteristic value indicating the sum of the areas of the portions from when the intensity of the AE signal, which is a waveform signal, exceeds a predetermined threshold value and again becomes less than the threshold value. This energy has a correlation with the area of cracks generated in the catalyst. That is, it is possible to more accurately detect a crack in the catalyst by determining whether or not a crack has occurred based on the energy of the AE wave.

  When energy is used as the characteristic value included in the AE wave, the determination device performs a smoothing process on the calculated energy, and the smoothed energy exceeds a predetermined reference value. In this case, it is preferable to determine that cracks have occurred in the catalyst.

  When energy is measured from the AE wave, the energy may include “abnormal value (excessive noise)” due to erroneous measurement or vibration generated from equipment other than the catalyst. If the energy contains abnormal values, it will be difficult to accurately detect cracks. In the crack occurrence detection device of the above aspect, by performing the “smoothing process”, an abnormal value is excluded from the measured energy, and the presence or absence of cracks is determined based on the smoothed energy. The cracks generated in the catalyst can be measured more accurately.

1 is a configuration diagram of a crack occurrence detection device according to Embodiment 1. FIG. It is a side view which fractures | ruptures and shows a part of crack generation detection apparatus which concerns on Embodiment 2. FIG. It is a side view which fractures | ruptures and shows a part of guide shaft which concerns on Embodiment 2. FIG. It is a side view which fractures | ruptures and shows a part of holder based on Embodiment 2. FIG. It is a side view which fractures | ruptures and shows a part of crack generation detection apparatus which concerns on Embodiment 3. FIG. It is a side view of the crack generation detection apparatus concerning Embodiment 3. It is a front view of the ball plunger which supports a guide shaft. It is a side view which fractures | ruptures and shows a part of crack generation detection apparatus which concerns on Embodiment 4. FIG. It is a perspective view of the cylindrical member (bearing) which penetrates a guide shaft. It is a block diagram which shows the exhaust passage of the internal combustion engine in which the crack generation detection apparatus which concerns on Embodiment 5 was provided. 10 is a flowchart for explaining the operation of the crack occurrence detection device according to the fifth embodiment. It is a block diagram which shows the exhaust passage of the internal combustion engine in which the crack generation detection apparatus which concerns on Embodiment 6 was provided. 10 is a flowchart for explaining the operation of the crack occurrence detection device according to the sixth embodiment. It is a block diagram which shows the exhaust passage of the internal combustion engine in which the crack generation detection apparatus which concerns on Embodiment 6 was provided. The figure which shows typically the AE signal detected by the crack generation | occurrence | production detection apparatus. 10 is a flowchart for explaining the operation of the crack occurrence detection device according to the seventh embodiment. 10 is a flowchart for explaining the operation of the crack occurrence detection device according to the eighth embodiment. 10 is a flowchart for explaining the operation of the crack occurrence detection device according to the ninth embodiment.

  Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

<Embodiment 1>
FIG. 1 shows a configuration of a crack occurrence detection apparatus 101 according to the first embodiment. The crack occurrence detection device 101 detects the occurrence of cracks in the catalyst 1 using the AE method. The catalyst 1 is disposed, for example, in an exhaust passage of an internal combustion engine, and purifies exhaust gas discharged from the internal combustion engine. The type of the catalyst 1 is not particularly limited. The catalyst 1 may be a monolith catalyst on which a noble metal such as platinum (Pt), palladium (Pd), or rhodium (Rd) is supported. Further, the catalyst 1 may be a DPF or the like on which a noble metal is supported.

  When cracks occur in the catalyst 1, elastic strain energy is released, and elastic waves (hereinafter referred to as AE waves) are generated. The crack occurrence detector 101 detects the occurrence of cracks in the catalyst 1 by detecting this AE wave. The crack occurrence detection device 1 includes an AE sensor 3 that can detect an AE wave (for example, a vibration wave of about several tens of kHz to 2 MHz). The AE sensor 3 includes an element that converts an AE wave into an electric signal. As such an element, for example, PZT (lead zirconate titanate piezoelectric ceramic) or the like can be suitably used.

  A data processing device 5 is connected to the AE sensor 3 through a signal line 4. Note that an amplifier for amplifying a signal, a filter circuit for removing a noise component, and the like may be provided between the AE sensor 3 and the data processing device 5 as necessary. The data processing device 5 is a device for recording, outputting, or analyzing a signal from the AE sensor 3. The data processing device 5 may be a dedicated data processing device, but may be constituted by a general-purpose computer or the like. The data processing device 5 is connected to a display device 18 capable of displaying a signal waveform. The data processing device 5 and the display device 18 may be separate from each other or may be integrated. The data processing device 5 and the display device 18 may be configured by, for example, a computer with a display (for example, a so-called notebook personal computer).

  A guide shaft 6 is provided between the catalyst 1 and the AE sensor 3. That is, the AE sensor 3 is not directly attached to the catalyst 1 but is indirectly attached to the catalyst 1 via the guide shaft 6. One end 6 a of the guide shaft 6 is in contact with the catalyst 1. The other end 6 b of the guide shaft 6 extends in a plate shape, and the other end 6 b is in contact with the AE sensor 3. The one end 6a and the other end 6b of the guide shaft 6 are preferably in direct contact with the catalyst 1 and the AE sensor 3, respectively, but indirectly as long as the AE wave can be transmitted. It may be in contact with. The guide shaft 6 need only be capable of transmitting AE waves from one end 6a to the other end 6b, and the material and structure thereof are not particularly limited.

  The AE sensor 3 is sandwiched between the other end 6 b of the guide shaft 6 and the plate 7. A buffer material 8 is provided between the AE sensor 3 and the plate 7. Thereby, it is suppressed that the AE sensor 3 detects an elastic wave from the plate 7, and the signal detected by the AE sensor 3 is less likely to contain noise. The plate 7 and the other end 6 b of the guide shaft 6 are fixed by bolts 9. The AE sensor 3 is disposed at a predetermined position by being sandwiched between the plate 7 and the other end 6 b of the guide shaft 6.

  One end 6a of the guide shaft 6 is formed in a curved surface so as not to cut the catalyst 1. In other words, the end 6a of the guide shaft 6 is rounded.

  The catalyst 1 is disposed in the case 2. A heat insulating material 10 is provided between the catalyst 1 and the inner surface of the case 2. A jig 11 is attached to the case 2. The jig 11 is for attaching the guide shaft 6 to the case 2. A heat insulating material 10 is interposed between the jig 11 and the catalyst 1. The jig 11 is formed in a bottomed cylindrical shape extending coaxially with the guide shaft 6, and a through hole 11 b through which the guide shaft 6 is inserted is formed in the bottom portion 11 a.

  In the vicinity of one end 6 a of the guide shaft 6, an annular portion 6 c that extends in the radial direction is formed. A compressed coil spring 12 is disposed between the annular portion 6 c and the bottom portion 11 a of the jig 11. Therefore, the guide shaft 6 receives a biasing force of the coil spring 12, and one end 6a of the guide shaft 6 is pressed against the catalyst 1 with a predetermined force (for example, 2 kgf to 6 kgf). Thereby, the one end 6 a of the guide shaft 6 is in close contact with the catalyst 1.

  Hot exhaust gas flows through the catalyst 1. Therefore, the catalyst 1 itself also becomes high temperature. In the crack occurrence detection device 101, a heat shield plate 13 is provided as a partition member that partitions the catalyst 1 and the AE sensor 3. The heat shield plate 13 may be a part of an exhaust passage (for example, an exhaust pipe) through which the exhaust gas flows, or may be a member provided separately from the exhaust passage. A part of the case 2 housing the catalyst 1 may also serve as a partition member.

  When a crack occurs in the catalyst 1, an AE wave is generated inside the catalyst 1. This AE wave is transmitted to the AE sensor 8 through the guide shaft 6. When the AE wave is transmitted to the AE sensor 8, an electrical signal is output from the AE sensor 8 to the data processing device 5. The data processing device 5 determines whether or not a crack has occurred based on a signal from the AE sensor 8. For example, the data processing device 5 determines whether or not the signal from the AE sensor 8 is a predetermined signal (for example, a signal whose output value is equal to or greater than a predetermined value) that is determined in advance as indicating the occurrence of a crack. When the signal from the AE sensor 8 is a predetermined signal, the data processing device 5 causes the display device 18 to output a predetermined display (for example, display of a warning message) that notifies the occurrence of a crack. Thereby, the user can recognize the occurrence of cracks in the catalyst 1 without removing the catalyst 1.

  As described above, according to the crack occurrence detection device 101, the occurrence of a crack in the catalyst 1 can be detected using the AE sensor 3. Therefore, the occurrence of cracks in the catalyst 1 can be detected without removing the catalyst 1.

  When the high-temperature exhaust gas flows through the catalyst 1, the catalyst 1 becomes high temperature. However, according to the crack generation detection device 101, the guide shaft 6 is interposed between the catalyst 1 and the AE sensor 3, and the catalyst 1 and the AE sensor 3 are partitioned by the heat shield plate 13. Even if the catalyst 1 becomes high temperature, the AE sensor 3 can be prevented from becoming high temperature. Therefore, it is possible to suppress sensor damage and measurement errors that may occur when the AE sensor 3 becomes hot. Further, according to the crack occurrence detection device 101, the one end 6 a of the guide shaft 6 is pressed against the catalyst 1 by the coil spring 12. Therefore, one end 6 a of the guide shaft 6 is in close contact with the catalyst 1. Therefore, the contact state between the guide shaft 6 and the catalyst 1 can be maintained satisfactorily, and generation of noise at the contact portion can be suppressed. Therefore, according to the crack generation detection apparatus 101, the occurrence of cracks in the catalyst 1 can be well detected while suppressing the AE sensor 3 from becoming high temperature.

  The guide shaft 6 is attached to the case 2 by a jig 11, and a heat insulating material 10 is provided between the jig 11 and the catalyst 1. Therefore, the jig 11 is suppressed from receiving heat from the catalyst 1 and becomes high temperature. As a result, the AE sensor 3 is prevented from receiving heat from the catalyst 1 via the jig 11 and the guide shaft 6. Therefore, it is possible to suppress the AE sensor 3 from becoming high temperature.

  One end 6a of the guide shaft 6 may be pointed in a conical shape, but is formed in a curved surface in the present embodiment. Therefore, there is little possibility that the catalyst 1 is scraped off by the guide shaft 6. Further, noise generated on the contact surface between the guide shaft 6 and the catalyst 1 can be reduced. Therefore, the contact state between the guide shaft 6 and the catalyst 1 can be kept good, and the occurrence of cracks in the catalyst 1 can be detected well.

<Embodiment 2>
FIG. 2 is a side view of the crack occurrence detection apparatus 102 according to the second embodiment. In FIG. 2, a part of the crack occurrence detection device 102 is shown broken away. The crack occurrence detection device 102 includes an AE sensor 3, a guide shaft 6, and a holder 20 that supports the guide shaft 6.

  As shown in FIG. 3, in the present embodiment, the annular portion 6 c is provided at a substantially central portion in the longitudinal direction of the guide shaft 6. As in the first embodiment, one end 6 a of the guide shaft 6 is disposed so as to contact the catalyst 1, and the other end 6 b of the guide shaft 6 is disposed so as to contact the AE sensor 3. A coil spring 12 and a pressure member 13 are provided between the annular portion 6 c and the other end 6 b of the guide shaft 6. The coil spring 12 is inserted through the guide shaft 6. The pressure member 13 includes a spring receiving member 13 a that receives the other end of the coil spring 12 and a fixing member 13 b that is fixed to the holder 20. As shown in FIG. 3, the spring receiving member 13a and the fixing member 13b are formed with through holes 13d through which the guide shaft 6 is inserted. The guide shaft 6 is inserted into the pressure member 13 so as to be movable in the axial direction. A part of the guide shaft 6 is supported in the radial direction by the pressure member 13. Specifically, a resin washer 15 is fitted around the through-hole 13 d of the fixing member 13 b, and a part of the other end side of the guide shaft 6 in the longitudinal direction is radially arranged by the washer 15. It is supported.

  As shown in FIG. 2, the holder 20 has a first through hole 21 having an inner diameter substantially the same as the outer diameter of the guide shaft 6 and a second inner diameter substantially the same as the outer diameter of the spring receiving member 13a. A through hole 22 is formed. The first through hole 21 is formed on the catalyst 1 side, and the second through hole 22 is formed on the AE sensor 3 side.

  The case 2 accommodates the catalyst 1 and forms an exhaust passage through which exhaust gas flows. The exhaust gas circulates in the front and back direction in FIG. The holder 20 extends in a direction orthogonal to the flow direction of the exhaust gas. Further, the case 2 serves as a partition member that partitions the catalyst 1 and the AE sensor 3. One end of the holder 20 is attached to the case 2. The method for attaching the holder 20 to the case 2 is not particularly limited. For example, the holder 20 may be welded to the case 2 or the holder 20 may be fixed to the case 2 using a fixing tool such as a bolt. Further, a slot having a thread groove may be formed in one of the holder 20 and the case 2 and a socket having a thread groove may be formed in the other, and the slot and the socket may be engaged.

  A washer 23 is provided on one end side of the holder 20. The washer 23 supports a portion on one end side of the guide shaft 6 in the radial direction. In this embodiment, the washer 23 is made of ceramic, but the material of the washer 23 is not particularly limited. Further, the member that supports the one end side portion of the guide shaft 6 is not limited to the washer 23, and other members such as a sliding bearing can be used as long as the transmission of the AE wave is not inhibited.

  As shown in FIG. 2, the spring receiving member 13 a is inserted into the second through hole 22. The fixing member 13 b is fixed to the holder 20. Although the fixing method of the fixing member 13b is not limited at all, for example, the fixing member 13b may be fixed to the holder 20 using a bolt or the like, or may be welded to the holder 20. One or more washers 14 are arranged between the right end surface of the holder 20 and the left end surface of the fixing member 13b. The washer 14 is for adjusting the distance L between the right end surface of the holder 20 and the left end surface of the fixing member 13b. The coil spring 12 is disposed in a compressed state between the annular portion 6c of the guide shaft 6 and the spring receiving member 13a. When the distance L changes, the distance between the annular portion 6c of the guide shaft 6 and the spring receiving member 13a changes, and the contraction length of the coil spring 12 changes. Therefore, by adjusting the L, the urging force of the coil spring 12 can be adjusted, and consequently the pressing force of the guide shaft 6 against the catalyst 1 can be adjusted. When the urging force of the coil spring 12 is maximized, the washer 14 is omitted and L = 0.

  Also in this embodiment, the guide shaft 6 is interposed between the catalyst 1 and the AE sensor 3, and the catalyst 1 and the AE sensor 3 are partitioned by the case 2. Therefore, even if the catalyst 1 becomes high temperature, it can suppress that the AE sensor 3 becomes high temperature. Further, the one end 6 a of the guide shaft 6 is pressed against the catalyst 1 by the urging force of the coil spring 12. Therefore, one end 6 a of the guide shaft 6 is in close contact with the catalyst 1. Also in the crack occurrence detection device 102 according to the present embodiment, the occurrence of cracks in the catalyst 1 can be well detected while suppressing the AE sensor 3 from becoming high temperature, and the same effect as in the first embodiment can be obtained. Can do.

  Furthermore, the crack generation detection apparatus 102 according to the present embodiment can also provide the effects described below. That is, in this embodiment, the guide shaft 6 is supported at two points by the holder 20. Specifically, a portion of one end side of the guide shaft 6 with respect to the middle position in the longitudinal direction is supported by the holder 20 via a washer 23 (see FIG. 2), and a portion on the other end side of the guide shaft 6 is a washer 15 ( 3) and the pressure member 13 is supported by the holder 20. Therefore, the guide shaft 6 can be supported stably, and it can be suppressed that noise is included in the signal detected by the AE sensor 3. Therefore, the occurrence of cracks in the catalyst 1 can be detected better.

  Further, according to the present embodiment, the pressing force of the guide shaft 6 against the catalyst 1 can be adjusted according to the type of the catalyst 1 and the like by adjusting the number of the washers 14 installed. Therefore, the contact state between the guide shaft 6 and the catalyst 1 can be adjusted according to the type of the catalyst 1 and the like, and the occurrence of cracks in the catalyst 1 can be detected even better.

  Also in this embodiment, the one end 6a of the guide shaft 6 is formed in a curved surface shape. This can prevent the catalyst 1 from being scraped by the guide shaft 6. However, the one end 6a of the guide shaft 6 is not necessarily curved, and may be, for example, flat.

<Embodiment 3>
The crack occurrence detection device 103 according to the third embodiment is the same as the crack occurrence detection device 102 according to the second embodiment, except that the washer 15 is used as a member for supporting the other end side of the guide shaft 6 in the radial direction of the guide shaft 6. Three ball plungers 30 (see FIG. 7) extending in the direction are provided.

  As shown in FIGS. 5 and 6, in the present embodiment, a holder 31 is provided in the vicinity of the other end 6 b of the guide shaft 6. The fixing member 13b and the guide shaft 6 are inserted through the holder 31. The holder 31 is formed with a through hole 13 c for inserting the ball plunger 30. Although not shown, the through holes 13 c extend radially from the center of the holder 31. A ball plunger 30 is inserted into each through-hole 13 c, and each ball plunger 30 is fixed to a holder 31. The outer peripheral surface of the guide shaft 6 is in contact with the ball 30 a at the tip of the ball plunger 30, and the guide shaft 6 is supported by the ball plunger 30 so as to be movable in the axial direction. Although not shown, a spring that presses the ball 30 a against the outer peripheral surface of the guide shaft 6 is accommodated inside the ball plunger 30. The ball 30a is movable in the radial direction of the guide shaft 6 by the spring. The ball plunger 30 constitutes an elastic body that can be elastically deformed in the radial direction of the guide shaft 6.

  As shown in FIG. 5, the fixing member 13 b is fixed to the holder 31 with a bolt 32. Since the pressure member 13 is fixed to the holder 20, the holder 31 is indirectly fixed to the holder 20. Since other configurations are the same as those of the second embodiment, description thereof is omitted.

  According to the present embodiment, in addition to the effects of the second embodiment, the following effects can be obtained. Since the guide shaft 6 is long in the longitudinal direction, bending deformation may occur. Therefore, when the other end side of the guide shaft 6 is supported by the washer 15 (see FIG. 3), when the guide shaft 6 is slightly bent, a gap between the outer peripheral surface of the guide shaft 6 and the inner peripheral surface of the washer 15 is generated. There is a risk that it will not be uniform in the circumferential direction. As a result, rattling occurs between the guide shaft 6 and the washer 15, and noise may occur. However, according to the present embodiment, the other end side of the guide shaft 6 is supported in the radial direction at three locations by the ball plunger 30 (see FIG. 7). The ball 30 a of the ball plunger 30 can be elastically deformed in the radial direction of the guide shaft 6. Therefore, even if the guide shaft 6 is slightly bent, there is little risk of a gap between the guide shaft 6 and the ball 30a of the ball plunger 30, and there is little risk of rattling. Therefore, generation | occurrence | production of noise can be suppressed and generation | occurrence | production of the crack of the catalyst 1 can be detected more correctly.

  In the present embodiment, the ball plungers 30 are arranged at equal intervals with respect to the circumferential direction of the guide shaft 6. However, the arrangement intervals of the ball plungers 30 may be uneven.

  The ball plunger 30 is only an example of an elastic body that can be elastically deformed in the radial direction of the guide shaft 6, and it is of course possible to use other elastic bodies as such an elastic body. For example, as another example of the elastic body, an O-ring made of resin or the like, or a ring-shaped member that can be elastically deformed inside the washer 15 (see FIG. 3) can be used.

  The means for preventing the rattling is not limited to the one using the elastic body. For example, it is possible to pack other members in the clearance between the support portion of the holder 20 and the guide shaft 6 without using the elastic body. For example, in the first embodiment, when a clearance is generated between the washer 15 and the guide shaft 6 due to the bending of the guide shaft 6 or the like, the clearance may be filled with another member.

<Embodiment 4>
The crack occurrence detection device 104 according to the fourth embodiment is configured by a cylindrical member 56 that allows a guide shaft to be inserted as a support portion instead of the washer 15 in the crack occurrence detection device 102 (see FIG. 3) according to the second embodiment. A dedicated bearing 50 (see FIGS. 8 and 9) is arranged.

  As shown in FIG. 9, the bearing 50 used in the crack occurrence detection device 104 according to the present embodiment is configured by a cylindrical member 56 in which an insertion hole 52 is formed. The cylindrical member 56 of the bearing 50 is preferably made of, for example, stainless steel or aluminum. A coating layer 54 is formed on the inner peripheral surface of the cylindrical member 56 of the bearing 50 (that is, the surface in contact with the inserted guide shaft 6). The coating layer 54 is made of a material having a lower frictional resistance than the cylindrical member 56. The material constituting the coating layer 54 can be appropriately selected in consideration of the relationship with the guide shaft 6 and the cylindrical member 56. As a specific example, a material having a frictional resistance (friction coefficient) of 0.1 or less can be preferably used as the material constituting the coating layer 54. For example, fluororesin (for example, polytetrafluoroethylene, tetrafluoroethylene, perfluoroalkyl vinyl ether copolymer), composite plating of graphite, molybdenum disulfide, boron nitride, etc., DLC coating, etc. are preferable.

  The bearing 50 is disposed at the end 20 b of the holder 20 on the AE sensor 3 side. The guide shaft 6 is inserted through the insertion hole 52 of the cylindrical member 56 of the bearing 50, and the coating layer 54 is in contact with the surface of the guide shaft 6 (see FIG. 8).

  According to the present embodiment, in addition to the effects of the second embodiment, the following effects can be obtained. The guide shaft 6 vibrates due to vibration of the entire engine or the like. At this time, if the clearance (interval) between the guide shaft 6 and the member supporting the guide shaft 6 is large, the guide shaft 6 vibrates in the radial direction and collides with the supporting member, so that the secondary AE is performed. Signals may be generated. On the other hand, if the clearance is set to a minimum in order to suppress the generation of a secondary AE signal, the metal (the guide shaft 6 and the member that supports the guide shaft 6) comes into contact with each other. The movement of the guide shaft 6 in the axial direction according to the expansion / contraction of the base material is limited, and it becomes difficult to keep the pressing force of the guide shaft 6 against the catalyst 1 constant. On the other hand, in the present embodiment, in the support portion 50 constituted by the cylindrical member 56, a coating made of a material having a lower frictional resistance than the cylindrical member 56 on the inner peripheral surface of the cylindrical member 56. Layer 54 is formed. As a result, even if the clearance is set to be minimal in order to suppress the generation of the secondary AE signal, the axial movement of the guide shaft 6 according to the expansion / contraction of the base material of the catalyst 1 is prevented. This makes it easy to keep the pressing force of the guide shaft 6 against the catalyst 1 constant. Therefore, the occurrence of cracks in the catalyst 1 can be detected more accurately.

  In the configuration shown in FIG. 8, a support portion (bearing) 50 is disposed at the end 20 b of the holder 20 on the AE sensor 3 side. However, if the guide shaft 6 can be supported, the support portion (bearing) is supported. 50 may be arrange | positioned in the other site | part. For example, the support part 50 may be arrange | positioned at the edge part by the side of the catalyst 1 of the holder 20, and the support part 50 may be arrange | positioned in the intermediate part in the longitudinal direction of the holder 20 (in this case, the support part 50). And the coil spring 12 are preferably arranged so as not to contact each other).

<Embodiment 5>
The crack generation detection apparatus according to the present invention can be used for detection of cracks in a catalyst used for various applications. As shown in FIG. 10, in the embodiment described below, the crack occurrence detection device 100 according to the present invention is applied to the catalyst 1 provided in the exhaust passage 43 of the internal combustion engine 41. Note that any of the crack occurrence detection devices 101 to 104 according to the embodiment can be used for the crack occurrence detection device 100. Since the crack occurrence detection device 100 is the same as the crack occurrence detection devices 101 to 104 of the embodiment, the description thereof is omitted.

  In the present embodiment, the internal combustion engine 41 is a diesel engine. The exhaust passage 43 is provided with a catalyst 1 as a small oxidation catalyst and a catalyst 45 as an exhaust purification catalyst. The catalyst 1 promotes the activation of the catalyst 45 and is arranged on the upstream side of the catalyst 45. Catalyst 1 and catalyst 45 are monolith catalysts on which a noble metal such as platinum is supported. A fuel injection valve 42 is disposed on the upstream side of the catalyst 1.

  When the fuel F is injected from the fuel injection valve 42 into the catalyst 1, the fuel F is oxidized in the catalyst 1. At this time, heat of oxidation reaction is generated in the catalyst 1, and the temperature of the catalyst 1 rises. As a result, the exhaust gas G is heated by the catalyst 1, and the higher temperature exhaust gas G is supplied to the catalyst 45. Therefore, the temperature of the catalyst 45 also rises and the activation of the catalyst 45 is promoted. If more fuel F is supplied to the catalyst 1 while the catalyst 45 is activated, a part of the supplied fuel F is reformed by the catalyst 1. The reformed fuel is supplied to the catalyst 45 and oxidized. As a result, the temperature of the catalyst 45 further increases, and the activation of the catalyst 45 is further promoted.

  When the supply of the fuel F to the catalyst 1 is stopped, the temperature of the catalyst 1 rapidly decreases. At this time, cracks are likely to occur in the catalyst 1. Therefore, in the present embodiment, detection of cracks in the catalyst 1 is started when the fuel injection of the fuel injection valve 42 is stopped, that is, when the fuel is cut.

  The data processing device 5 is communicably connected to the ECU 44. The data processing device 5 receives a signal from the ECU 44 and acquires information on the engine speed, the engine load factor, and the fuel injection amount.

  Next, a method for detecting cracks in the catalyst 1 in this embodiment will be described with reference to the flowchart of FIG. First, in step S1, the data processing device 5 determines whether or not the engine speed and the load factor are each equal to or greater than a predetermined value. If the determination result is YES, the process proceeds to step S2, and if NO, the process returns to step S1. In step S2, the data processing device 5 determines whether or not the fuel injection of the fuel injection valve 42 is stopped (whether a fuel injection stop signal is received from the ECU). That is, the data processing device 5 determines whether there is no fuel injection. If the determination result is YES, the process proceeds to step S3, and if NO, the process returns to step S1.

  In step S3, the data processing device 5 starts detecting AE waves. Subsequently, in step S4, the data processing device 5 determines whether or not the signal from the AE sensor 3 matches a signal (for example, a signal whose output value is equal to or greater than a predetermined value) that is predetermined as a signal when a crack occurs. Determine whether. In other words, the data processing device 5 determines whether or not a predetermined signal (AE signal) related to the AE wave is detected. If a determination result is NO, it will return to Step S2 and will repeat processing after Step S2 again. If a determination result is YES, it will progress to step S5 and the data processor 5 will display that the abnormality had generate | occur | produced on the display apparatus 18, assuming that the crack generate | occur | produced.

  The occurrence of cracks may be detected for a predetermined time after the fuel cut is started, or may be performed during the fuel cut (that is, during the period from when the fuel injection is stopped to when it is restarted).

  As described above, in the present embodiment, the crack is detected after the fuel cut in which the crack of the catalyst 1 is likely to occur. Accordingly, it is possible to omit a useless detection operation in an operation state in which a crack does not normally occur. Therefore, it is possible to efficiently detect the occurrence of cracks.

  However, it is of course possible to always detect the occurrence of cracks. The present invention includes one that constantly detects the occurrence of cracks.

  In the above embodiment, a diesel engine is used as an example of the internal combustion engine. However, the type of internal combustion engine to which the crack occurrence detection device according to the present invention is applied is not limited at all, and may be an internal combustion engine other than a diesel engine. For example, the internal combustion engine may be a gasoline engine.

  In a gasoline engine, the air-fuel ratio is usually made rich in order to lower the catalyst temperature in a high load region. That is, the air-fuel ratio is made smaller than the theoretical air-fuel ratio. However, this causes a deterioration in fuel consumption in a high load region. In order to improve fuel consumption, it is preferable to expand the region where stoichiometric combustion is performed to the region on the high load side. However, in that case, the catalyst temperature rises. If fuel cut is performed in such a state by turning off the accelerator or the like, the catalyst temperature rapidly decreases and cracks are likely to occur. Therefore, even when the internal combustion engine is a gasoline engine, the crack may be detected after the fuel cut as in the above embodiment. Thereby, generation | occurrence | production detection of a crack can be performed efficiently.

<Embodiment 6>
Hereinafter, the crack generation detection apparatus according to the sixth embodiment will be described. Any of the crack occurrence detection devices 101 to 104 according to the above-described embodiments can be used for the crack occurrence detection device described in this embodiment. Therefore, the description regarding the structure of the crack occurrence detection device is omitted here.

  The crack occurrence detection device according to the sixth embodiment includes a computer. The computer includes a calculation unit including a CPU and a storage unit including a non-volatile memory. The computer 1 performs cracks in the catalyst 1 by performing various electronic calculation processes according to a preset program. Various determinations in detection are made. In this embodiment, as shown in FIG. 12 (or FIG. 14), a data processing device 5 is provided as the computer.

  The data processing device (computer) 5 functions as at least a determination unit 5a and a detection start unit 5b described later. The determination unit 5a performs various determinations based on a “predetermined state” described later. The “predetermined state” is a predetermined state, and is stored in, for example, data stored in the storage unit or a computer program. Moreover, the detection start part 5b starts the detection of generation | occurrence | production of a crack, when the determination part 5a determines with it being the said "predetermined state."

Here, it is preferable to set a state in which the catalyst 1 is rapidly cooled as the “predetermined state”. For example, “a state where fuel injection of the internal combustion engine is stopped”, “a state where the accelerator opening is rapidly decreased”, “a state where the temperature of the catalyst is rapidly decreased” and the like can be mentioned. As will be described in detail below, cracks are likely to occur in the catalyst 1 in any of the above-described states, so in these states, by trying to detect cracks, useless detection can be omitted, It becomes possible to perform efficient detection. The determination unit 5a may determine only one of the above states, or may make a determination by combining a plurality of states.
Hereinafter, a specific example of the “predetermined state” described above will be described.

As shown in FIG. 12, when the crack occurrence detection device according to the present invention is applied to the catalyst 1 provided in the exhaust passage 43 of the internal combustion engine 41, the “predetermined state” is “the fuel of the internal combustion engine”. A state where injection is stopped can be employed. When the injection of the fuel F is stopped, the temperature of the catalyst 1 is likely to rapidly decrease, and cracks are likely to occur. Therefore, efficient detection can be performed by starting detection of cracks when such a state occurs.
In order to start crack detection when it is determined that “the fuel injection of the internal combustion engine has stopped”, for example, a configuration is adopted in which a “fuel injection stop signal” can be transmitted from the ECU 44 to the determination unit 5a. Good. And it is good to preset beforehand to the judgment part 5a that "the detection of a crack is started when the fuel injection stop signal produced by ECU44 is received." Thereby, the determination part 5a can determine whether it is in the "state where the fuel injection has stopped". When it is determined that the fuel injection is stopped, the detection start unit 5b starts detecting cracks.

In the case of the configuration shown in FIG. 12, the “predetermined state” may be set to “a state where the accelerator opening is rapidly reduced”. When the accelerator opening is rapidly reduced, the temperature of the exhaust gas G from the internal combustion engine 41 is lowered, the temperature of the catalyst 1 is likely to be rapidly lowered, and cracks are likely to occur. Therefore, efficient detection can be performed by starting detection of cracks when such a state occurs.
In order to start crack detection when it is determined that “the accelerator opening is suddenly reduced”, the determination unit 5a sets a reference value for the amount of decrease in the accelerator opening in advance and within a predetermined time. A configuration may be adopted in which information related to the accelerator opening can be transmitted from the ECU 44 to the determination unit 5a. Then, the determination unit 5a is set to “start crack detection when the amount of decrease in the accelerator opening within a predetermined time exceeds the reference value”. As a result, the determination unit 5a can determine whether or not it is in the “state in which the accelerator opening is rapidly decreased”, and is determined to be in the “state in which the accelerator opening is rapidly decreased”. In such a case, the detection start unit 5b starts detecting cracks.

Further, as shown in FIG. 14, when one or more temperature sensors 9 are attached to the catalyst 1, the estimated temperature of the catalyst 1 can be measured. “The state in which the temperature of the catalyst has suddenly decreased” can be set. In this case, when the temperature of the catalyst measured by the temperature sensor 9 is drastically reduced, efficient detection can be performed by starting detection of cracks. In the configuration shown in FIG. 14, one temperature sensor 9 is attached to the catalyst 1. However, the present invention is not limited to this, and a plurality of temperature sensors may be attached to the catalyst 1.
In order to start crack detection when it is determined that “the temperature of the catalyst has suddenly decreased”, the determination unit 5a causes a reference value (for example, 15 ° C./sec) for the amount of decrease in the estimated temperature of the catalyst 1 over a predetermined time. It is preferable to adopt a configuration in which ˜80 ° C./sec (preferably 40 ° C./sec˜80° C./sec) is determined in advance and the estimated temperature of the catalyst within a predetermined time can be transmitted from the temperature sensor 9 to the determination unit 5a. Then, it is preset that “crack detection starts when the amount of decrease in the estimated temperature of the catalyst within a predetermined time exceeds a predetermined reference value.” As a result, the determination unit 5a determines that “the temperature of the catalyst is It is possible to determine whether or not it is in a “suddenly lowered state”, and when it is determined that it is in “a state in which the temperature of the catalyst has rapidly decreased”, the detection start unit 5b detects a crack. To start.

  Further, the crack occurrence detection device according to the present embodiment includes a determination device 5c. In the present embodiment, the determination device 5c is provided in the data processing device (computer) 5 together with the determination unit 5a and the detection start unit 5b. The determination device 5 c determines whether or not a crack has occurred in the catalyst 1 based on the characteristic value included in the AE wave detected by the AE sensor 3. In the crack occurrence detection device according to the present embodiment, “strength S”, “hit number N”, and “energy E” can be measured as characteristic values included in the AE wave.

  “Intensity S” is a value indicating the amplitude of the AE wave viewed from the reference value B, as shown in FIG. The reference value B can be set arbitrarily. For example, a value in a state where no AE signal is detected can be set as the reference value B. In addition, in the determination device 5c of the present embodiment, a predetermined threshold value Th is set in advance for the intensity S in order to measure other characteristic values (“number of hits N”, “energy E”). . Note that the threshold Th for the intensity S can be changed as appropriate in consideration of the measurement situation (noise or the like). For example, the threshold Th may be set to a value within a range of 20 db to 50 db (preferably 30 db to 40 db).

  As shown in FIG. 15, the “number of hits N” is a characteristic value indicating the number of recorded signals (hits) having an intensity S exceeding the threshold Th among the AE signals that are waveform signals. In general, the hit number N tends to increase due to the occurrence of cracks in the catalyst 1. Therefore, the presence / absence of cracks in the catalyst 1 is determined by comparing the hit number N measured within the predetermined time period (within a predetermined unit time) with a predetermined reference value. can do. The unit time for measuring the hit number N may be set to a value within the range of 5 seconds to 120 seconds (preferably 10 seconds to 60 seconds). When the threshold Th for the intensity S is set to 40 db, the reference value for the “number of hits N” is 0 times / second (at least once within the unit time) to 30 times / second (more preferably 4 times). / Second to 10 times / second).

“Energy E” is a characteristic value indicating the sum of the areas of the portions (shaded portions in FIG. 15) from when the intensity S of the AE signal, which is a waveform signal, exceeds the threshold value Th to become less than the threshold value Th again. It is. Such energy E can be calculated, for example, by integrating the absolute value of the signal exceeding the threshold value Th within a predetermined unit time over the duration. The energy E has a correlation with the area of cracks generated in the catalyst. Therefore, the presence or absence of cracks in the catalyst 1 can be determined by comparing the measured energy E with a predetermined reference value. For example, when a catalyst base of φ100 × L100 is used as the catalyst 1, the reference value for “energy E” is 4 × 10 ⁴ to 4 × 10 ⁵ (more preferably 1 × 10 ⁵ to 4 × 10 ⁵ ). It is preferable to set a value within the range.

  Moreover, the determination apparatus 5c according to the present embodiment can perform a smoothing process on the energy E. The “smoothing process” is a process for excluding “abnormal value (excessive noise)” due to erroneous measurement or vibration generated from equipment other than the catalyst from the measured energy E. Various methods can be employed as the smoothing process.

  The following process is mentioned as an example of the said smoothing process. In this process, first, a predetermined value is cut from a value (maximum value) having the highest intensity S among the detected signals. Then, energy E is calculated based on a signal obtained by cutting a predetermined value from the maximum value. The predetermined value in this process may be set to 1% to 20% (preferably 10%) with respect to the entire signal.

  Next, crack detection in the present embodiment will be described with reference to the flowchart of FIG.

  In the crack occurrence detection device according to the present embodiment, first, it is determined whether or not the determination unit 5a of the data processing device 5 is in the “predetermined state” (S10). If the determination result at this time is NO, the process returns to step S10 to continue monitoring whether or not the “predetermined state” is reached. On the other hand, when the determination result is YES, it is determined that the catalyst 1 is within the crack detection range, and the process proceeds to step S20. In step S20, the detection start unit 5b starts detecting the AE signal in order to start detecting the crack.

  The AE signal detected by the detection start unit 5b is sent to the determination device 5c. The determination device 5c measures the intensity S, the hit number N, and the energy E based on the sent AE signal (S30). Then, it is determined whether or not the measured number of hits N exceeds a predetermined reference value (S40). If the determination result at this time is NO, the process returns to step S10 and continues to monitor whether or not the “predetermined state” is reached. On the other hand, if the determination result is YES, the determination device 5c determines that the hit number N is within the crack occurrence region, and proceeds to the next step S50.

  In step S50, the determination device 5c performs a smoothing process on the energy E measured in step S30, and excludes an abnormal value (excessive noise) from the measured energy E. Next, the determination device 5c determines whether or not the energy E excluding the abnormal value exceeds a predetermined reference value (S60). If the determination result at this time is NO, the process returns to step S10 and continues to monitor whether or not the “predetermined state” is reached. On the other hand, if the determination result is YES, the determination device 5c determines that the energy E is within the crack occurrence region, proceeds to step S70, determines that a crack has occurred in the catalyst 1, and an abnormality has occurred in the display device 18. Display the effect.

According to this embodiment, the following effects can be obtained.
In the crack occurrence detection device according to the present embodiment, a predetermined “predetermined state” (for example, “a state where fuel injection of the internal combustion engine is stopped”, “a state where the accelerator opening is suddenly reduced”, “ When the determination unit 5a determines that the catalyst temperature is in a state where the temperature of the catalyst has rapidly decreased, the detection start unit 5b starts detecting cracks. By starting crack detection only when it is determined that this “predetermined state”, it is possible to omit useless detection and perform efficient detection.

  Further, in the crack detection device according to the present embodiment, the determination device 5c determines whether or not a crack has occurred in the catalyst based on the characteristic values (number of hits N, energy E) included in the AE wave. The hit number N tends to increase when a crack occurs in the catalyst. The energy E has a correlation with the area of cracks generated in the catalyst. That is, since the determination is performed based on these characteristic values, a crack generated in the catalyst can be detected nondestructively and accurately.

  In the present embodiment, a smoothing process is performed on the energy E, and it is determined that a crack has occurred in the catalyst when the smoothed energy E exceeds a predetermined reference value. Thereby, since it can be determined whether or not a crack has occurred based on the energy E excluding an abnormal value (excessive noise), the crack can be detected more accurately.

  In the present embodiment, it is determined whether or not a crack has occurred based on both the hit number N and the energy E (S40 and S60 in FIG. 13). For this reason, it is possible to detect the occurrence of cracks more accurately than the determination based on only one of “number of hits N” and “energy E”.

<Embodiment 7>
A crack occurrence detection apparatus according to Embodiment 7 will be described. Note that the crack occurrence detection device described in this embodiment can employ the same configuration as the crack occurrence detection device according to the sixth embodiment described above. Therefore, the description regarding the configuration of the crack occurrence detection device is omitted here. Hereinafter, crack detection in the crack occurrence detection apparatus of the seventh embodiment will be described with reference to the flowchart shown in FIG.

  In the crack occurrence detection device according to the present embodiment, first, it is determined whether or not the determination unit 5a of the data processing device 5 is in the “predetermined state” (S10). If the determination result at this time is NO, the process returns to step S10 to continue monitoring whether or not the “predetermined state” is reached. On the other hand, when the determination result is YES, it is determined that the catalyst 1 is within the crack detection range, and the process proceeds to step S20. In step S20, the detection start unit 5b starts detecting an AE signal in order to start detecting a crack.

  The AE signal detected by the detection start unit 5b is sent to the determination device 5c. The determination device 5c measures the intensity S and energy E based on the sent AE signal (S32). In step S50, the measured energy E is smoothed to exclude “abnormal value (excessive noise)”. Next, the determination device 5c determines whether or not the energy E excluding the abnormal value exceeds a predetermined reference value (S60). If the determination result at this time is NO, the process returns to step S10 and continues to monitor whether or not the “predetermined state” is reached. On the other hand, if the determination result is YES, the determination device 5c determines that the energy E is within the crack occurrence region, proceeds to step S70, assumes that a crack has occurred in the catalyst 1, and indicates that an abnormality has occurred in the display device 18. Is displayed.

  Unlike the sixth embodiment, the present embodiment includes a step of measuring the hit number N from the AE signal (see S30 in FIG. 13) and a step of determining the measured hit number N (see S40 in FIG. 13). Not. However, the crack occurrence detection device of the present invention can detect a crack generated in the catalyst 1 even when it is based only on the energy E of the AE signal.

<Eighth embodiment>
A crack occurrence detection apparatus according to Embodiment 8 will be described. Note that the crack occurrence detection device described in this embodiment can employ the same configuration as the crack occurrence detection device according to the sixth embodiment described above. Therefore, the description regarding the configuration of the crack occurrence detection device is omitted here. Hereinafter, crack detection in the crack occurrence detection apparatus of the eighth embodiment will be described with reference to the flowchart shown in FIG.

  In the crack occurrence detection device according to the present embodiment, first, it is determined whether or not the determination unit 5a of the data processing device 5 is in the “predetermined state” (S10). If the determination result at this time is NO, the process returns to step S10 to continue monitoring whether or not the “predetermined state” is reached. On the other hand, if the determination result is YES, it is determined that the catalyst 1 is within the crack detection range, and the process proceeds to step S20. In step S20, the detection start unit 5b starts detecting an AE signal in order to start detecting a crack.

  The AE signal detected by the detection start unit 5b is sent to the determination device 5c. The determination device 5c measures the intensity S, the hit number N, and the energy E based on the sent AE signal (S30). Then, it is determined whether or not the measured number of hits N exceeds a predetermined reference value (S40). If the determination result at this time is NO, the process returns to step S10 and continues to monitor whether or not the “predetermined state” is reached. On the other hand, if the determination result is YES, the determination device 5c determines that the hit number N is within the crack occurrence region, and proceeds to the next step (S62).

  In step S62, the determination device 5c determines whether or not the energy E measured in step S30 exceeds a predetermined reference value. If the determination result at this time is NO, the process returns to step S10 and continues to monitor whether or not the “predetermined state” is reached. On the other hand, if the determination result is YES, the determination device 5c determines that the energy E is within the crack occurrence region, proceeds to step S70, assumes that a crack has occurred in the catalyst 1, and indicates that an abnormality has occurred in the display device 18. Is displayed.

  Unlike the sixth embodiment, the present embodiment does not include a step (see S50 in FIG. 12) of performing a smoothing process on the measured energy E (excluding abnormal values) (see S50 in FIG. 12). The presence or absence of cracks is determined based on the above. However, even in this case, a crack generated in the catalyst 1 can be detected.

<Ninth Embodiment>
A crack occurrence detection apparatus according to Embodiment 9 will be described. Note that the crack occurrence detection device described in this embodiment can employ the same configuration as the crack occurrence detection device according to the sixth embodiment described above. Therefore, the description regarding the configuration of the crack occurrence detection device is omitted here. Hereinafter, crack detection in the crack occurrence detection apparatus of Embodiment 9 will be described with reference to the flowchart shown in FIG.

  In the crack occurrence detection device according to the present embodiment, first, it is determined whether or not the determination unit 5a of the data processing device 5 is in the “predetermined state” (S10). If the determination result at this time is NO, the process returns to step S10 to continue monitoring whether or not the “predetermined state” is reached. On the other hand, if the determination result is YES, it is determined that the catalyst 1 is “in the crack detection range”, and the process proceeds to step S20. In step S20, the detection start unit 5b starts detecting an AE signal in order to start detecting a crack.

  The AE signal detected by the detection start unit 5b is sent to the determination device 5c. The determination device 5c measures the strength S and the hit number N based on the sent AE signal (S34). Then, it is determined whether or not the measured number of hits N exceeds a predetermined reference value (S40). If the determination result at this time is NO, the process returns to step S10 and continues to monitor whether or not the “predetermined state” is reached. On the other hand, if the determination result is YES, the determination device 5c determines that the hit number N is within the crack generation region, proceeds to the next step (S70), regards that the crack has occurred in the catalyst 1, and Display that an error has occurred.

  Unlike the sixth embodiment, the present embodiment does not include the step of measuring the energy E from the AE signal (see S30 in FIG. 12), and the step of determining the crack occurrence region based on the energy E (FIG. 12). (See S60). However, the crack occurrence detection device of the present invention can detect a crack generated in the catalyst 1 even when only based on the number of hits.

  As mentioned above, although this invention was demonstrated in detail, the said embodiment is only an illustration and what changed and modified the above-mentioned specific example is included in the invention disclosed here.

DESCRIPTION OF SYMBOLS 1 Catalyst 2 Case 3 AE sensor 5 Data processor 6 Guide shaft 10 Heat insulating material 12 Coil spring (biasing member)
13 Heat shield (partition member)
15 Washer (supporting part)
20 Holder 23 Washer (support part)
30 Ball plunger 41 Diesel engine (internal combustion engine)
42 Fuel injection valve 43 Exhaust passage

Claims (14)

A crack occurrence detection device for detecting the occurrence of cracks in a catalyst for purifying exhaust gas,
An AE sensor that detects AE waves;
A partition member for partitioning the AE sensor and the catalyst;
A guide shaft penetrating the partition member and having one end in contact with the catalyst and the other end in contact with the AE sensor, and capable of transmitting AE waves from the one end to the other end;
A biasing member that biases the guide shaft so as to press one end of the guide shaft against the catalyst;
A catalyst crack detection device comprising: A holder formed with a through hole through which the guide shaft is inserted;
Support portions for supporting the guide shaft in the radial direction are provided on one end side and the other end side from the intermediate position in the longitudinal direction of the holder, respectively.
2. The catalyst crack occurrence detection device according to claim 1, wherein the biasing member includes a spring having one end engaged with the guide shaft and the other end engaged with the holder.   The catalyst crack occurrence detection device according to claim 2, wherein the support portion on the other end side of the holder has an elastic body that is elastically deformable at least in a radial direction of the guide shaft. The support portion is configured by a cylindrical member having an insertion hole through which the guide shaft is inserted,
The catalyst crack occurrence detection device according to claim 2, wherein a coating layer made of a material having a lower frictional resistance than that of the cylindrical member is formed on the inner peripheral surface of the cylindrical member.   The catalyst crack occurrence detection device according to any one of claims 1 to 4, wherein an end surface of the one end side of the guide shaft is formed in a curved surface shape. The portion on the one end side of the holder is attached to a case that houses the catalyst,
The catalyst according to any one of claims 1 to 5, further comprising a heat insulating material interposed between the holder and the catalyst.   A computer comprising: a determination unit that determines whether or not a predetermined state is set in advance; and a detection start unit that starts detection of the occurrence of cracks in the catalyst when the determination unit determines that the predetermined state is present. The crack generation detection apparatus of the catalyst as described in any one of Claims 1-6 equipped. The catalyst is disposed in an exhaust passage of the internal combustion engine;
The catalyst crack occurrence detection device according to claim 7, wherein the predetermined state is a state in which fuel injection of the internal combustion engine is stopped. The catalyst is disposed in an exhaust passage of the internal combustion engine;
9. The catalyst according to claim 7, wherein the predetermined state is a state in which a decrease amount of an accelerator opening for adjusting the rotational speed of the internal combustion engine within a predetermined time exceeds a predetermined reference value. Crack occurrence detection device. One or more temperature sensors are attached to the catalyst;
The predetermined state is a state in which the amount of decrease in the estimated temperature of the catalyst obtained from the temperature sensor within a predetermined time exceeds a predetermined reference value. The crack generation detection apparatus of the described catalyst.   The crack generation of the catalyst according to any one of claims 1 to 10, further comprising a determination device that determines whether or not a crack is generated in the catalyst based on a characteristic value included in the AE wave. Detection device.   The determination device measures the number of hits of the AE wave as a characteristic value included in the AE wave, and determines that a crack has occurred in the catalyst when the number of hits exceeds a predetermined reference value. The catalyst crack occurrence detection device according to claim 11.   The determination device calculates the energy of the AE wave as a characteristic value included in the AE wave, and determines that a crack has occurred in the catalyst when the energy exceeds a predetermined reference value. The catalyst crack generation detection device according to claim 11 or 12. The determination device performs a smoothing process on the calculated energy, and determines that a crack has occurred in the catalyst when the smoothed energy exceeds a predetermined reference value. 13. A crack detection apparatus for a catalyst according to item 13.

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