Patent Publication Number: US-11384674-B2

Title: Reuse evaluation system for catalyst

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from Japanese patent application JP 2020-054266 filed on Mar. 25, 2020, the entire content of which is hereby incorporated by reference into this application. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a reuse evaluation system for a catalyst that performs an evaluation to reuse the catalyst that purifies an exhaust gas of an engine of a vehicle. 
     Background Art 
     Conventionally, a vehicle includes an exhaust gas purification device to purify an exhaust gas discharged from an engine of the vehicle. The exhaust gas purification device includes a catalyst that purifies the exhaust gas from the engine. WO2011/099164 discloses to diagnose a deterioration of this catalyst using, for example, a Cmax method. However, when a vehicle was discarded, such a catalyst was discarded together with the vehicle even though the catalyst had a little deterioration. 
     SUMMARY 
     While in WO2011/099164, the deterioration of the catalyst is diagnosed from a perspective of a purification performance of the catalyst in the case where the catalyst is mounted on the vehicle, the deterioration of the catalyst is not diagnosed from a perspective of reusing the catalyst. That is, a purification performance requested for the catalyst differs depending on a usage of the catalyst when it is reused. 
     The present disclosure has been made in view of such a point, and the present disclosure provides a reuse evaluation system that ensures appropriately performing an evaluation of reuse of a catalyst according to a usage of the reuse when the catalyst that purifies an exhaust gas of an engine of a vehicle is reused. 
     In view of the problem, a reuse evaluation system according to the present disclosure is a system for performing an evaluation to reuse a catalyst in a state where the catalyst that purifies an exhaust gas of an engine of a vehicle is mounted on the vehicle. The system comprises a deterioration estimator, a reuse setting unit, and a reuse determining unit. The deterioration estimator estimates a degree of deterioration of the catalyst based on an operating state of the vehicle. The reuse setting unit sets a range of the degree of deterioration of the catalyst as a reuse range of the catalyst according to a usage of reuse of the catalyst. The reuse determining unit determines that the catalyst is reusable in the reuse usage when the degree of deterioration of the catalyst estimated by the deterioration estimator is within the reuse range set by the reuse setting unit. 
     According to the present disclosure, first, the deterioration estimator estimates the degree of deterioration of the catalyst based on the operating state of the vehicle. Note that the degree of deterioration of the catalyst is a quantified degree of deterioration of the catalyst, and the higher the degree of deterioration of the catalyst is, the lower the purification efficiency of the exhaust gas by the catalyst becomes. From such a point, the range of the degree of deterioration of the catalyst is set in the reuse setting unit as the reuse range of the catalyst according to the usage of the reuse of the catalyst in the present disclosure. Since the reuse determining unit determines that the catalyst is reusable in the reuse usage when the degree of deterioration of the catalyst estimated by the deterioration estimator is within the reuse range set by the reuse setting unit, the evaluation of the reuse of the catalyst (that is, the catalyst is reusable or not) according to the reuse usage can be appropriately performed when the catalyst is reused. 
     In some embodiments, the reuse evaluation system further includes a misfire detector that detects a misfire of the engine. When the misfire detector has detected the misfire of the engine, the reuse determining unit determines that the catalyst is unreusable. 
     Usually, when the misfire of the engine is detected by the misfire detector, an uncombusted gas mixed with a fuel and an intake air passes through the catalyst as the exhaust gas to cause the catalyst to excessively generate heat to often damage the catalyst. Accordingly, since the reuse determining unit can determine such a catalyst is unreusable even though the degree of deterioration of the catalyst is within the reuse range, the evaluation of reuse of the catalyst according to the reuse usage can be appropriately performed when the catalyst is reused. 
     Here, the degree of deterioration of the catalyst may be estimated from a running distance of the vehicle, an operating period of the engine, and the like. However, in some embodiments, the deterioration estimator estimates the degree of deterioration of the catalyst based on at least one of an output accumulated time, a bed temperature accumulated time, or a combustion accumulated time in a period from the vehicle was manufactured until the degree of deterioration of the catalyst is estimated. The output accumulated time is an accumulated time where the engine is within a predetermined output range. The bed temperature accumulated time is an accumulated time where a bed temperature of the catalyst is within a predetermined range. The combustion accumulated time is an accumulated time where the engine performed lean burn. 
     Generally, when the output of the engine is within a predetermined range (for example, a range of high output), the exhaust gas discharged from the engine easily deteriorates the catalyst. When the bed temperature of the catalyst is within a predetermined range (for example, a range of higher temperature than a normal temperature) due to purification of the exhaust gas, the catalyst is easily deteriorated. Furthermore, when the engine performs lean burn (when it is driven with an air-fuel mixture thinner than a stoichiometric air-fuel ratio), the bed temperature of the catalyst increases to easily deteriorates the catalyst. 
     Accordingly, in this aspect, the degree of deterioration of the catalyst is estimated according to at least one value of the output accumulated time, the bed temperature accumulated time, or the combustion accumulated time as the accumulated times of states where the catalyst is easily deteriorated. In view of this, the deterioration estimator can further accurately estimate the degree of deterioration of the catalyst according to the operating state of the vehicle. 
     Here, the deterioration estimator may estimate the degree of deterioration of the catalyst from, for example, a formula, a graph, or a table, such that, for example, the degree of deterioration of the catalyst increases as at least one value of the output accumulated time, the bed temperature accumulated time, or the combustion accumulated time increases. However, as described above, while the output accumulated time, the bed temperature accumulated time, and the combustion accumulated time are parameters pertaining to the deterioration of the catalyst, unambiguously estimating the degree of deterioration of the catalyst by one parameter may fail to accurately estimate the degree of deterioration of the catalyst. Accordingly, the degree of deterioration of the catalyst is estimated by comprehensively taking these parameters into account in some embodiments. 
     As such an aspect, the deterioration estimator further includes a deterioration learning unit that has machine-learned a calculation of the degree of deterioration of the catalyst using the output accumulated time, the bed temperature accumulated time, the combustion accumulated time, and a degree of deterioration of a catalyst as teacher data for each catalyst of a plurality of the catalysts for learning. The deterioration learning unit receives the output accumulated time, the bed temperature accumulated time, and the combustion accumulated time of a catalyst as a target for which degree of deterioration is to be estimated and calculates the degree of deterioration of the catalyst as the target for which degree of deterioration is to be estimated. 
     This aspect includes the learning unit that has machine-learned the calculation of the degree of deterioration of the catalyst using values of the output accumulated time, the bed temperature accumulated time, and the combustion accumulated time, which have large influences on the degree of deterioration of the catalyst, and the degree of deterioration of the catalyst calculated with these values as the teacher data. The calculation of the degree of deterioration of the catalyst learned by such a learning unit ensures further accurately estimating the degree of deterioration of the catalyst. Note that an actually measured degree of deterioration of the catalyst may be used as the degree of deterioration of the catalyst that serves as the teacher data, and a degree of deterioration of the catalyst estimated for a catalyst that could obtain an effective purification efficiency at the time of reuse among the already estimated degrees of deterioration of the catalysts may be used. 
     In some embodiments, the reuse evaluation system further includes a deterioration predictor that predicts a progress of the degree of deterioration of the catalyst corresponding to the accumulated time from any one of the accumulated times of the output accumulated time, the bed temperature accumulated time, or the combustion accumulated time, and the degree of deterioration of the catalyst estimated by the deterioration estimator. 
     According to this aspect, the deterioration estimator can estimate the degree of deterioration of the catalyst with high accuracy, and therefore, the degree of deterioration of the catalyst can be accurately estimated with any one of the accumulated times of the output accumulated time, the bed temperature accumulated time, or the combustion accumulated time as a time axis. 
     Here, the reuse usage is one and a range of the degree of deterioration of the catalyst may be set for the one reuse usage. However, in some embodiments, the reuse setting unit sets a range of the degree of deterioration of the catalyst for each of a plurality of reuse usages, and the reuse determining unit determines whether the catalyst is reusable based on the range of the degree of deterioration of the catalyst set for each of the plurality of reuse usages. According to this aspect, since the range of the degree of deterioration of the catalyst is set for each of the plurality of reuse usages, the catalyst can be reused in a further wide range of the degree of deterioration of the catalyst. 
     In some embodiments, the reuse evaluation system for the catalyst may be mounted on each vehicle, but, for example, it may be mounted on a server or the like installed outside the vehicle. For this case, in some embodiments, the deterioration estimator estimates the degree of deterioration of the catalyst of each of the vehicles with respect to the catalysts of a plurality of the vehicles, and the reuse evaluation system further includes a vehicle number specifying unit that identifies a vehicle including a catalyst determined to be reusable among the plurality of vehicles and a number of the vehicle. 
     According to this aspect, since the vehicle including the catalyst reusable for the usage and the number of the vehicle are identified with respect to the plurality of vehicles, the number of the catalyst that can be supplied as the reusable catalyst can be controlled. This facilitates securing it before the vehicle is discarded. 
     The present disclosure ensures appropriately performing an evaluation of reuse of a catalyst according to a usage of the reuse when the catalyst that purifies an exhaust gas of an engine of a vehicle is reused. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a main part of a vehicle including a catalyst evaluated with a reuse evaluation system according to an embodiment of the disclosure; 
         FIG. 2  is a schematic diagram of a catalytic converter including a vehicular catalyst illustrated in  FIG. 1 ; 
         FIG. 3  is a block diagram of the reuse evaluation system illustrated in  FIG. 1 ; 
         FIG. 4  is a block diagram of a deterioration estimator illustrated in  FIG. 1 ; 
         FIG. 5  is a graph for describing a calculation method by an output accumulated time calculator, a bed temperature accumulated time calculator, and a combustion accumulated time calculator illustrated in  FIG. 4 ; 
         FIG. 6  is a schematic diagram illustrating an exemplary deterioration learning unit illustrated in  FIG. 4 ; 
         FIG. 7  is a graph for describing a setting for each of a plurality of reuse usages by a deterioration setting unit and a prediction of the deterioration of the catalyst performed by a deterioration predictor illustrated in  FIG. 4 ; 
         FIG. 8  is a flowchart for describing an evaluation method for reusing the catalyst using the reuse evaluation system for catalyst according to the embodiment; and 
         FIG. 9  is a schematic diagram that illustrates a modification of the reuse evaluation system illustrated in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     1. Catalyst to be Evaluated for Reuse and Vehicle Including the Same 
     The following describes a catalyst to be evaluated for reuse and a vehicle including the catalyst with reference to  FIG. 1  and  FIG. 2 . 
     As illustrated in  FIG. 1 , an engine  7  mounted on a vehicle is coupled to an intake air pipe  62 , and an amount of intake air that passes through the intake air pipe  62  is adjusted by controlling a degree of opening of a throttle valve  61 . 
     The adjusted intake air flows into a combustion chamber  79 , formed of a cylinder block  71  and a piston  72 , via an intake air valve  73 , and is mixed with a fuel (gasoline) injected by a fuel injection valve  74 . The mixed air-fuel mixture is ignited by a spark plug  75  and combusted in the combustion chamber  79 , an exhaust gas after the combustion is discharged from an exhaust manifold  77  via an exhaust valve  76 . 
     The exhaust gas exhausted from the exhaust manifold  77  is purified in an exhaust gas purification device  8 . Specifically, the exhaust gas purification device  8  includes a catalytic converter  80  coupled to the exhaust manifold  77  and a catalytic converter  84  coupled to the catalytic converter  80  in the downstream side of the catalytic converter  80 . 
     The catalytic converter  80  includes a catalyst  81  that purifies the exhaust gas from the exhaust manifold  77  and a housing  82  that houses the catalyst  81 . The catalytic converter  84  also similarly includes a catalyst  85  that further purifies the exhaust gas that is not fully purified by the catalytic converter  80  and a housing  86  that houses the catalyst  85 . The housings  82  and  86  are made of a metallic material, such as stainless steel, carbon steel, or aluminum. 
     In this embodiment, the same configurations are employed for the catalytic converter  80  in the upstream side of the exhaust gas and the catalytic converter  84  in the downstream side of the exhaust gas. The following describes the configuration of the catalytic converter  80  in the upstream side in detail, and the description of the configuration of the catalytic converter  84  in the downstream side is omitted. 
     As illustrated in  FIG. 2 , the housing  82  of the catalytic converter  80  has an inlet side cone  82   a , a trunk portion  82   b , and an outlet side cone  82   c . The exhaust gas from the exhaust manifold  77  flows into the inlet side cone  82   a , and the inlet side cone  82   a  has a cone shape with a flow-channel cross section of the exhaust gas enlarges from the upstream side toward the downstream side of the exhaust gas. The trunk portion  82   b  is formed to continue from the inlet side cone  82   a  in the upstream side of the flowing exhaust gas, and has a tubular shape with a constant flow-channel cross section of the exhaust gas. The outlet side cone  82   c  is formed to continue from the trunk portion  82   b  in the upstream side of the flowing exhaust gas, and has a cone shape with a flow-channel cross section of the exhaust gas decreases from the upstream side toward the downstream side of the exhaust gas. The catalyst  81  is arranged within the trunk portion  82   b.    
     In this embodiment, since the engine  7  is a gasoline engine, and the catalyst  81  is a three-way catalyst that converts hydrocarbon (HC), carbon monoxide (CO), and nitride oxide (NOx) in the exhaust gas of the gasoline engine. 
     The catalyst  81  is made of a carrier (catalyst carrier) supporting a metallic catalyst that purifies an exhaust gas. The carrier may be made of any materials of a ceramic material or a metallic material. Examples of the ceramic material can include a porous ceramic material containing any one of, for example, alumina, zirconia, cordierite, titania, silicon carbide, or silicon nitride as a main component. The metallic material is a material having heat resistance and corrosion resistance in some embodiments, and examples of the metallic material can include, for example, stainless steel and aluminum. 
     In this embodiment, as one example, the carrier of the catalyst  81  is a carrier in a cylindrical shape, made of a ceramic material, and has a honeycomb structure in which a plurality of cells where the exhaust gas passes are formed. 
     The metallic catalyst of the catalyst  81  is in a granular shape, and is supported via a ceramic material onto an inner wall surface that forms the cells of the catalyst  81 . A noble metal containing at least one of platinum, rhodium, or palladium is selected as a metal for the metallic catalyst. Examples of the ceramic material that causes the carrier to support the catalytic metal can include, for example, a mixed material of zirconia and alumina, ceria and alumina, or ceria-zirconia and alumina. For supporting the metallic catalyst on the carrier, coating the carrier with a slurry including the ceramic material and the metallic catalyst described above and firing this ensure it. The catalyst  81  thus mounted on a vehicle  1  is removed from the vehicle  1  in a form of the catalytic converter  80  when it is reused. 
     In this embodiment, a control device  10 A that controls traveling of the vehicle  1  is disposed. The control device  10 A is a device that controls, for example, the engine  7  of the vehicle  1 , and includes an arithmetic device, such as a CPU, and a storage device, such as a RAM and ROM, which are not illustrated. The arithmetic device computes, for example, a controlled variable for controlling the engine  7  described later. 
     The engine  7  includes a torque detection sensor  93  that detects a torque of the engine  7  and a crank angle detection sensor  94  that detects an engine speed by detecting a rotation angle of a crankshaft  78 . The torque of the engine  7  and the engine speed of the engine  7  detected by these sensors  93  and  94  are input to the control device  10 A. Furthermore, the catalytic converter  80  includes a temperature sensor  87  that detects a bed temperature of the catalyst  81 , and the detected bed temperature is input to the control device  10 A. 
     The control device  10 A outputs, for example, a control signal of a degree of opening of the throttle valve  61 , a control signal for controlling an injection timing and an injection amount of the fuel injection valve  74 , and a control signal for controlling an ignition timing by the spark plug  75 , in order to drive the engine  7  with a predetermined output, corresponding to a request from a driver. This ensures controlling the engine  7  of the vehicle  1 . 
     2. Reuse Evaluation System  10   
     In this embodiment, the vehicle  1  further includes a reuse evaluation system  10  described above. The reuse evaluation system  10  is a system to perform an evaluation for reusing the catalyst  81  in a state where the catalyst  81  is mounted on the vehicle  1 . The reuse evaluation system  10  includes an arithmetic device, such as a CPU, and a storage device, such as a RAM and ROM, which are not illustrated, similarly to the control device  10 A, and the reuse evaluation system  10  is coupled to an input device  91  and a display unit  92 . A reuse range of the catalyst, which will be described later, is input to the input device  91 , and a determination result of the reuse of the catalyst is output to the display unit  92 . 
     Note that, while in this embodiment, as illustrated in  FIG. 1 , the control device  10 A of the vehicle  1  and the reuse evaluation system  10  are individually disposed, they may be configured in one arithmetic device and storage device. The reuse evaluation system  10 , as software, includes a deterioration estimator  11 , a reuse setting unit  12 , a reuse determining unit  13 , a misfire detector  14 , and a deterioration predictor  15  as illustrated in  FIG. 3 . 
     2-1. Deterioration Estimator  11   
     The deterioration estimator  11  estimates a degree of deterioration of the catalyst  81  based on an operating state of the vehicle  1 . The degree of deterioration of the catalyst  81  is a numerical value that indicates a degree of lowered purification efficiency of purifying the exhaust gas by the catalyst  81 . Accordingly, the purification efficiency of the exhaust gas is high when the degree of deterioration of the catalyst  81  is low, and therefore, the catalyst  81  is easily reused. 
     For example, the deterioration estimator  11  may estimate the degree of deterioration of the catalyst  81  according to a running distance of the vehicle  1 , and may estimate the degree of deterioration of the catalyst  81  according to an oxygen storage capacity by measuring the oxygen storage capacity (Cmax) of the catalyst  81  by the Cmax method. In this case, a numerical value corresponding to the oxygen storage capacity may be used as a degree of deterioration of the catalyst. Note that, this Cmax method performs an air-fuel ratio control in which an air-fuel ratio is oscillated about a stoichiometry to forcibly change the air-fuel ratio of the exhaust gas flowing into the catalyst  81  between a lean side and a rich side. During this air-fuel ratio control, the oxygen occlusion capacity of the catalyst  81  can be calculated from an output value of an oxygen sensor (not illustrated) disposed in the downstream side of the catalyst  81 . 
     2-1-1. Estimation of Degree of Deterioration of Catalyst Using Accumulated Time 
     Unlike the above-described estimation of the degree of deterioration of the catalyst, the degree of deterioration of the catalyst  81  is estimated as illustrated in  FIG. 4  and  FIG. 5  in this embodiment. As illustrated in  FIG. 4 , the deterioration estimator  11  includes an output accumulated time calculator  11 A, a bed temperature accumulated time calculator  11 B, a combustion accumulated time calculator  11 C, and a deterioration learning unit  11 D. 
     The output accumulated time calculator  11 A accumulates a time during which the engine  7  is within a predetermined output range R 1  in a period from the vehicle  1  was manufactured until the degree of deterioration of the catalyst  81  is estimated. Specifically, as illustrated in  FIG. 5 , an output range (a range where an output of the engine  7  is high) R 1  of the engine  7  where the deterioration of the catalyst  81  progresses is set with respect to the output of the engine  7  detected by the torque detection sensor  93 . The output accumulated time calculator  11 A accumulates times A 1 , A 2 , A 3  . . . in this range R 1 . This causes the output accumulated time calculator  11 A to calculate an output accumulated time AT. 
     The bed temperature accumulated time calculator  11 B accumulates a time during which the bed temperature of the catalyst  81  is within a predetermined temperature range R 2  in the period from the vehicle  1  was manufactured until the degree of deterioration of the catalyst  81  is estimated. Specifically, as illustrated in  FIG. 5 , a temperature range (a high temperature range in activation of the catalyst  81 ) R 2  of the catalyst  81  where the deterioration of the catalyst  81  progresses is set with respect to the bed temperature of the catalyst  81  detected by the temperature sensor  87 . The bed temperature accumulated time calculator  11 B accumulates times B 1 , B 2 , B 3  . . . in this range R 2 . This causes the bed temperature accumulated time calculator  11 B to calculate the bed temperature accumulated time BT. 
     The combustion accumulated time calculator  11 C accumulates a time during which the engine  7  performs lean burn in the period from the vehicle  1  was manufactured until the degree of deterioration of the catalyst  81  is estimated. Specifically, as illustrated in  FIG. 5 , the combustion accumulated time calculator  11 C accumulates time C 1 , C 2 , C 3  . . . during which the engine  7  performed lean burn from a target air-fuel ratio for controlling or the air-fuel ratio of the engine  7  detected by an air-fuel ratio sensor (not illustrated). The combustion accumulated time calculator  11 C calculates a combustion accumulated time CT. 
     The longer the output accumulated time AT, the bed temperature accumulated time BT, and the combustion accumulated time CT get, the larger the degree of deterioration of the catalyst  81  becomes. Accordingly, the deterioration estimator  11  may estimate the degree of deterioration of the catalyst  81  according to any one of the calculated output accumulated time AT, bed temperature accumulated time BT, or combustion accumulated time CT. 
     However, while the output accumulated time AT, the bed temperature accumulated time BT, or the combustion accumulated time CT are parameters pertaining to the deterioration of the catalyst  81 , estimating the degree of deterioration of the catalyst  81  by one parameter may fail to accurately estimate the degree of deterioration of the catalyst  81 . Accordingly, the degree of deterioration of the catalyst  81  is estimated by comprehensively taking these parameters into account in some embodiments. 
     2-1-2. Calculation of Degree of Deterioration of Catalyst by Machine Learning (Artificial Intelligence) 
     Therefore, in this embodiment, the deterioration learning unit  11 D that calculates the degree of deterioration of the catalyst  81  from these accumulated times AT, BT, and CT is disposed. Specifically, the deterioration learning unit  11 D has machine-learned a calculation of the degree of deterioration of the catalyst with the output accumulated time, the bed temperature accumulated time, the combustion accumulated time, and the degree of deterioration of the catalyst  81  as teacher data for each catalyst of a plurality of catalysts. 
     In this embodiment, the deterioration learning unit  11 D is configured of a deep neural network  11 D′ ((DNN): hereinafter referred to as a “neural network”) illustrated in  FIG. 6  as one example. The output accumulated time A 1 , the bed temperature accumulated time B 1 , and the combustion accumulated time C 1  of the catalyst  81  as a target for which degree of deterioration is to be estimated is input to the neural network  11 D′ of the deterioration learning unit  11 D, and the degree of deterioration of the catalyst  81  as the target for which degree of deterioration is to be estimated is calculated. 
     The neural network  11 D′ includes an input neuron element  11   a  to which the output accumulated time A 1 , the bed temperature accumulated time B 1 , and the combustion accumulated time C 1  are input, an output neuron element  11   d  from which the degree of deterioration of the catalyst  81  is output, and intermediate neuron elements  11   b  and  11   c  that serve as middle layers to couple them. While in this embodiment, the intermediate neuron elements  11   b  and  11   c  are configured of two layers, the number of the layers is not limited to this. As illustrated in  FIG. 6 , each of the neuron elements  11   a ,  11   b ,  11   c , and  11   d  are linked in this order. A neuron parameter computed by this linked neuron element is input to each of the neuron elements, and values obtained by substituting an activation function for this neuron parameter are multiplied by weighting factors to compute a new neuron parameter. 
     When learning the calculation of the degree of deterioration of the catalyst  81  as an artificial intelligence, the output accumulated time, the bed temperature accumulated time, and the combustion accumulated time calculated for the catalyst for learning are input to the input neuron element  11   a . Together with this, the degree of deterioration of the catalyst for learning is also input. This causes the output neuron element  11   d  to calculate the degree of deterioration of the catalyst, and the weighting factor of each neuron element is corrected such that this degree of deterioration of the catalyst falls within the predetermined range, and thus, the learning of the calculation of the degree of deterioration of the catalyst is performed. As the teacher data, the output accumulated time, the bed temperature accumulated time, and the combustion accumulated time for an actually used catalyst and the degree of deterioration of the catalyst measured for this catalyst are used. The measured degree of deterioration of the catalyst may be, for example, a value measured by the above-described Cmax method, and the degree of deterioration of the catalyst used as the teacher data is not specifically limited as long as the degree of deterioration of the catalyst can be more accurately measured or calculated. 
     Thus, the neural network  11 D′ established by correcting the weighting factor is used in a phase of utilization of an artificial intelligence. In view of this, when the output accumulated time AT, the bed temperature accumulated time BT, and the combustion accumulated time CT of the catalyst  81  as the target for which degree of deterioration is to be evaluated are input to the input neuron element  11   a , the degree of deterioration of the catalyst  81  is calculated from the output neuron element  11   d , and the degree of deterioration of the catalyst  81  can be more accurately estimated. 
     2-2. Reuse Setting Unit  12   
     The reuse setting unit  12  sets the range of the degree of deterioration of the catalyst  81  as a reuse range of the catalyst  81  according to a usage of reuse of the catalyst  81 . In this embodiment, as illustrated in  FIG. 7 , the reuse setting unit  12  sets ranges of the degree of deterioration of the catalyst  81  for each of usages A to C of a plurality of reuses. These settings are performed via the input device  91 . 
     The reuse setting unit  12  sets a range where the degree of deterioration of the catalyst  81  is 0 or more and less than D 1  as a reuse range U 1  in reuse usage A. Similarly, the reuse setting unit  12  sets a range where the degree of deterioration of the catalyst  81  is D 1  or more and less than D 2  as a reuse range U 2  in reuse usage B. Similarly, the reuse setting unit  12  sets a range where the degree of deterioration of the catalyst  81  is D 2  or more and less than D 3  as a reuse range U 3  in reuse usage C. 
     Note that, in this embodiment, a range where the degree of deterioration of the catalyst  81  is D 3  or more is set as a range where the catalyst  81  is unreusable. Note that, while in this embodiment, the three reuse usages A to C are exemplarily illustrated, one reuse usage and a reuse range corresponding to this may be set or a plurality of reuse usages other than three and reuse ranges corresponding to these may be set. 
     Here, in  FIG. 7 , the reuse ranges U 1  to U 3  are sectioned such that the ranges of the degree of deterioration of the catalyst do not overlap corresponding to the reuse usages A to C, but the ranges of the degree of deterioration of the catalyst may overlap for the reuse ranges U 1  to U 3 . 
     For example, the reuse usage A is use of the catalyst  81  for replacement for another vehicle with a damaged catalyst. The reuse usage B is use of the catalyst to generate hydrogen. Specifically, the catalytic converter  80  including the catalyst  81  is installed on a supply pipe to which a gas containing carbon monoxide (for example, city gas) and water vapor is supplied and a discharge pipe. The carbon monoxide and the water vapor are supplied via the supply pipe, and by their reforming reactions, hydrogen and carbon dioxide are generated. The reuse usage C is use of the catalyst  81  that purifies an exhaust gas discharged from a furnace and the like. 
     The reuse usages A to C are the examples and the usages are not limited to these. The reuse ranges U 1  to U 3  of the catalyst corresponding to the reuse usages A to C are determined by a performance required to the catalyst  81 . 
     2-3. Reuse Determining Unit  13   
     The reuse determining unit  13  determines that the catalyst  81  is reusable in the reuse usage U 1  (U 2 , U 3 ) when the degree of deterioration of the catalyst  81  estimated by the deterioration estimator  11  is within the reuse range U 1  (U 2 , U 3 ) set by the reuse setting unit  12 . 
     In this embodiment, the reuse determining unit  13  determines whether the catalyst  81  is reusable based on the range of the degree of deterioration of the catalyst  81  (that is, the reuse ranges U 1 , U 2 , and U 3 ) set for each of the plurality of reuse usages A to C. For example, as illustrated in  FIG. 7 , when the degree of deterioration of the catalyst  81  is estimated as “d” by the deterioration estimator  11 , the degree of deterioration “d” is in the reuse range U 2  as the range of D 1  or more and less than D 2 , and therefore, it is determined as the reuse usage B. Note that when the degree of deterioration of the catalyst  81  is D 3  or more by the deterioration estimator  11 , it is determined that there is no reuse usage (that is, reuse is impossible) of the catalyst  81 . Thus, the result determined by the reuse determining unit  13  is output to the display unit  92 . 
     2-4. Misfire Detection of Misfire Detector  14  and Reuse Determination 
     The misfire detector  14  detects a misfire of the engine  7 . The misfire of the engine  7  is determined that a fuel injected in the combustion chamber  79  of the engine  7  is not combusted (the engine  7  misfired) when, for example, the misfire detector  14  calculates an engine speed of the engine  7  from a rotation angle of the crankshaft  78  detected by the crank angle detection sensor  94 , and a variation of the engine speed of the engine  7  exceeds a predetermined range. 
     Here, the reuse determining unit  13  determines that the catalyst  81  is unreusable when the misfire of the engine  7  has been detected by the misfire detector  14 . In this case, the reuse determining unit  13  determines that the reuse of the catalyst  81  is impossible even when the degree of deterioration of the catalyst  81  is within the range where the reuse is possible (specifically, the degree of deterioration of the catalyst is less than D 3 ). 
     Thus, when the misfire of the engine is detected by the misfire detector  14 , an uncombusted gas mixed with the fuel and the intake air passes through the catalyst  81  as the exhaust gas to cause the catalyst  81  to excessively generate heat to often damage the catalyst  81 . Accordingly, since the reuse determining unit  13  can determine such a catalyst  81  is unreusable even though the degree of deterioration of the catalyst  81  is within the reuse range, the evaluation of reuse of the catalyst  81  according to the reuse usage can be appropriately performed when the catalyst  81  is reused. Thus, the result determined by the reuse determining unit  13  is output to the display unit  92  together with the result of the misfire of the engine  7 . 
     2-5. Deterioration Predictor  15   
     The deterioration predictor  15  predicts a progress of the degree of deterioration of the catalyst  81  corresponding to the accumulated time from any one of the accumulated times of the output accumulated time, the bed temperature accumulated time, or the combustion accumulated time calculated by the deterioration estimator  11  and the degree of deterioration of the catalyst  81  estimated by the deterioration estimator  11 . 
     Specifically, as illustrated in  FIG. 7 , for example, using any one of the accumulated times of the output accumulated time, the bed temperature accumulated time, or the combustion accumulated time as a time axis, the degree of deterioration of the catalyst  81  is estimated as the accumulated time increases. As illustrated in  FIG. 7 , for example, continuously estimating the degree of deterioration of the catalyst  81  by the deterioration estimator  11  ensures obtaining a deterioration curve  51  for a period by an accumulated time t. 
     Next, a deterioration prediction curve S 2  of the degree of deterioration of the catalyst  81  that increases as the accumulated time proceeds is calculated from this deterioration curve  51 . For the deterioration prediction curve S 2 , by setting a standard curve (not illustrated) of the degree of deterioration of the catalyst  81  with respect to the accumulated time using, for example, a function for a catalyst of the same kind as the catalyst  81 , the deterioration prediction curve S 2  may be calculated from this function. When the deterioration curve  51  is approximately rectilinear, the deterioration prediction curve S 2  may be calculated by a least-square method by assuming that this deterioration curve  51  and the deterioration prediction curve S 2  are straight. Thus, the deterioration predictor  15  predicts the progress of the degree of deterioration of the catalyst  81  corresponding to the accumulated time, and outputs this prediction result to the display unit  92 , for example, in a form of a graph illustrated in  FIG. 7 , in a form of a table of the accumulated time and the degree of deterioration of the catalyst that increase from now on. Thus, predicting the degree of deterioration of the catalyst  81  ensures predicting reusability of the catalyst  81  in the usage. 
     3. Reuse Evaluation Method Using Reuse Evaluation System  10   
     The following describes a reuse evaluation method with reference to a flowchart illustrated in  FIG. 8 . First, at Step S 81 , a reuse range of the catalyst  81  according to a reuse usage of the catalyst  81  is set via the input device  91 . This sets the range of the degree of deterioration of the catalyst  81  in the reuse setting unit  12  according to the reuse usage of the catalyst  81 . 
     Next, at Step S 82 , the output accumulated time calculator  11 A, the bed temperature accumulated time calculator  11 B, and the combustion accumulated time calculator  11 C of the deterioration estimator  11  calculate an output accumulated time AT, a bed temperature accumulated time BT, and a combustion accumulated time CT in a state where the catalyst  81  that purifies an exhaust gas of the engine  7  of the vehicle  1  is mounted on the vehicle  1 . 
     Next, at Step S 83 , the output accumulated time AT, the bed temperature accumulated time BT, and the combustion accumulated time CT, which are calculated, are input in the deterioration learning unit  11 D, and the deterioration learning unit  11 D calculates the degree of deterioration of the catalyst  81 . Thus, the deterioration estimator  11  can estimate the degree of deterioration of the catalyst  81  in the state of being mounted on the vehicle  1 . Note that, in the deterioration learning unit  11 D, those (program) learned from the teacher data described above has been generated and saved before Step S 81 . 
     Next, at Step S 84 , the reuse determining unit  13  determines whether the degree of deterioration of the catalyst  81  estimated by the deterioration estimator  11  is within the reuse range set by the reuse setting unit  12 . Note that the reuse range referred to here is that the degree of deterioration of the catalyst  81  is within the range of 0 or more and less than D 3  illustrated in  FIG. 7 . Here, when the degree of deterioration of the catalyst  81  is outside the reuse range set by the reuse setting unit  12 , that is, when the degree of deterioration of the catalyst  81  is D 3  or more, the procedure proceeds to Step S 88 , and the reuse determining unit  13  determines that the catalyst  81  is not reusable. 
     At Step S 85 , when the degree of deterioration of the catalyst  81  is within the reuse range set by the reuse setting unit  12 , the procedure proceeds to Step S 85 , and the misfire detector  14  determines whether a misfire of the engine  7  mounted on the vehicle  1  is detected or not. Here, when the misfire of the engine  7  is detected, the procedure proceeds to Step S 88 , and the reuse determining unit  13  determines that the catalyst  81  is not reusable. 
     At Step S 86 , since the catalyst  81  is reusable from the series of Steps, a reuse usage of the catalyst  81  is identified based on the degree of deterioration of the catalyst  81 . For example, in the case illustrated in  FIG. 7 , the catalyst  81  has the degree of deterioration of the catalyst  81  of “d,” and therefore, it is determined to be the reuse usage B. 
     At Step S 87 , the deterioration predictor  15  predicts a progress of the deterioration of the catalyst  81 , and outputs the result obtained through the series of these Steps to the display unit  92 . 
     Thus, this embodiment ensures appropriately performing an evaluation of reuse of the catalyst  81  according to the reuse usage when the catalyst  81  that purifies an exhaust gas of the engine  7  of the vehicle  1  is reused. 
     Note that, while in this embodiment, the reuse evaluation system  10  is mounted on the vehicle  1 , for example, as illustrated in  FIG. 9 , the reuse evaluation system  10  may be disposed outside the vehicle in a form of a server, and the reuse evaluation system  10  may perform evaluations of reuse of a plurality of the vehicles  1  via a network  6 . 
     In this case, the deterioration estimator  11  of the reuse evaluation system  10  estimates the degree of deterioration of the catalyst  81  for each of the vehicles  1  with respect to the catalysts  81  of the plurality of vehicles  1 . The reuse determining unit  13  determines whether the catalyst  81  is reusable in the reuse usage of the catalyst  81  for each of the vehicles  1 . 
     The reuse evaluation system  10  further includes a vehicle number specifying unit  16  in addition to those illustrated in  FIG. 3 . The vehicle number specifying unit  16  identifies the vehicle  1  that includes the catalyst  81  determined to be reusable and the number thereof with respect to the plurality of vehicles among the plurality of vehicles  1 . More specifically, in this embodiment, the reuse setting unit  12  sets the range of the degree of deterioration of the catalyst  81  for each of the plurality of reuse usages A to C. Accordingly, the vehicle number specifying unit  16  identifies the vehicle  1  determined to have the reusable catalyst  81  and the number thereof for each usage with respect to the plurality of vehicles  1 . 
     Since this aspect identifies the vehicle  1  including the reusable catalyst for the usages A to C and the number thereof with respect to the plurality of vehicles  1 , the number of the catalysts  81  that can be supplied as the reusable catalyst  81  according to the usage can be controlled. This can easily secure the catalyst  81  to be reused for each usage before the vehicle  1  is discarded. 
     While one embodiment of the present disclosure has been described in detail, the present disclosure is not limited to the above-described embodiment, but various kinds of changes of design are allowed within a range not departing from the spirits of the present disclosure described in the claims.