KR102664119B1 - Apparatus for diagnosing deterioration of doc and method thereof - Google Patents

Abstract

The present invention relates to a device and method for diagnosing the deterioration of a diesel oxidation catalyst, which can diagnose the deterioration of the diesel oxidation catalyst with high accuracy by diagnosing the deterioration of the diesel oxidation catalyst in consideration of the operating conditions of the vehicle. The object is to provide a diagnostic device and method.
To this end, the present invention is a device for diagnosing the deterioration of a diesel oxidation catalyst, by applying a variable threshold according to the RPM of the engine and the amount of fuel consumed by the engine to the difference between the current temperature of the diesel oxidation catalyst and the target temperature to determine whether the diesel oxidation catalyst is deteriorated. A first deterioration diagnosis unit that diagnoses; a second deterioration diagnosis unit that diagnoses whether the diesel oxidation catalyst is deteriorated based on the temperature of the coolant, the temperature of the outside air, the temperature of the intake air, the temperature of the diesel oxidation catalyst, the fuel injection amount for exhaust incineration, and the target temperature of the diesel oxidation catalyst; and a control unit that finally diagnoses whether the diesel oxidation catalyst is deteriorated based on the diagnosis result of the first degradation diagnosis unit and the diagnosis result of the second degradation diagnosis unit.

Description

Diesel oxidation catalyst deterioration diagnosis device and method {APPARATUS FOR DIAGNOSING DETERIORATION OF DOC AND METHOD THEREOF}

The present invention relates to a technology for diagnosing deterioration of a diesel oxidation catalyst with high accuracy.

In general, DOC (Diesel Oxidation Catalyst) is partially coated with a precious metal catalyst mixed with platinum and palladium in a weight ratio of 1:0 to 1:3 from the inlet to 1/3 of the length, thereby reducing carbon monoxide emissions from diesel vehicles. , soluble organic substances among hydrocarbons and PM (Particulate Matter) are oxidized and purified into carbon dioxide and water that are harmless to the human body.

The conventional technology for diagnosing the deterioration of the DOC diagnoses that the DOC has deteriorated when the temperature at the outlet side of the DOC is below a fixed threshold while the HCI (HydroCarbon Injection) module is injecting fuel for exhaust incineration.

Therefore, the conventional DOC deterioration diagnosis technology does not consider the vehicle's operating conditions, so there is a problem in that the accuracy of diagnosis is significantly reduced.

The matters described in this background art section have been prepared to enhance understanding of the background of the invention, and may include matters that are not prior art already known to those skilled in the art in the field to which this technology belongs.

Republic of Korea Patent No. 10-0962875

In order to solve the problems of the prior art as described above, the present invention is a deterioration diagnosis device for a diesel oxidation catalyst that can diagnose the deterioration of the diesel oxidation catalyst with high accuracy by diagnosing the deterioration of the diesel oxidation catalyst in consideration of the operating conditions of the vehicle. The purpose is to provide and method.

The objects of the present invention are not limited to the objects mentioned above, and other objects and advantages of the present invention that are not mentioned can be understood from the following description and will be more clearly understood by the examples of the present invention. Additionally, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof indicated in the patent claims.

The device of the present invention for achieving the above object is a device for diagnosing the deterioration of a diesel oxidation catalyst, by applying a variable threshold according to the RPM of the engine and the amount of fuel consumed by the engine to the difference between the current temperature and the target temperature of the diesel oxidation catalyst. a first deterioration diagnosis unit that diagnoses whether the diesel oxidation catalyst is deteriorated; a second deterioration diagnosis unit that diagnoses whether the diesel oxidation catalyst is deteriorated based on the temperature of the coolant, the temperature of the outside air, the temperature of the intake air, the temperature of the diesel oxidation catalyst, the fuel injection amount for exhaust incineration, and the target temperature of the diesel oxidation catalyst; and a control unit that finally diagnoses whether the diesel oxidation catalyst is deteriorated based on the diagnosis result of the first degradation diagnosis unit and the diagnosis result of the second degradation diagnosis unit.

Here, the first deterioration diagnosis unit determines the current threshold value based on a map in which threshold values corresponding to the RPM of the engine and the amount of fuel consumed by the engine are recorded, and subtracts the current temperature of the diesel oxidation catalyst from the target temperature of the diesel oxidation catalyst. If the value is below the determined threshold, it can be diagnosed that deterioration has occurred in the diesel oxidation catalyst.

In addition, the first deterioration diagnosis unit includes a memory in which a map in which threshold values corresponding to the RPM of the engine and the amount of fuel consumed by the engine are recorded; A first detector that detects whether fuel for soot incineration is injected; A temperature sensor that measures the temperature of the diesel oxidation catalyst; a second detector that detects the RPM of the engine; a third detector that detects the amount of fuel consumed by the engine; And based on the map, determine the current threshold corresponding to the RPM of the engine detected by the second detector and the amount of fuel consumed by the engine detected by the third detector, and determine the current threshold when the fuel for exhaust incineration is being injected. If the value obtained by subtracting the current temperature from the target temperature of the oxidation catalyst is less than the determined threshold, it may include a controller that diagnoses that deterioration has occurred in the diesel oxidation catalyst.

In addition, the second deterioration diagnosis unit determines whether the temperature of the coolant exceeds the first standard value, the temperature of the outside air exceeds the second standard value, the temperature of the intake air exceeds the third standard value, and the current diesel oxidation catalyst is at the target temperature. If the value minus the temperature of the oxidation catalyst is greater than the critical value, the fuel injection amount for exhaust incineration is within the first critical range, and the target temperature of the diesel oxidation catalyst is within the second critical range, it can be diagnosed that deterioration has occurred in the diesel oxidation catalyst. .

In addition, if the control unit diagnoses that any one of the first degradation diagnosis unit and the second degradation diagnosis unit is deteriorated, it can finally diagnose that the diesel oxidation catalyst is deteriorated.

Additionally, the control unit may diagnose whether the diesel oxidation catalyst is deteriorated in a standard regeneration mode among engine operation modes.

The method of the present invention for achieving the above object is a method of diagnosing the deterioration of a diesel oxidation catalyst, wherein the first deterioration diagnosis unit determines the difference between the current temperature and the target temperature of the diesel oxidation catalyst according to the RPM of the engine and the amount of fuel consumed by the engine. A first diagnosis step of diagnosing whether the diesel oxidation catalyst is deteriorated by applying a variable threshold; The second deterioration diagnosis unit diagnoses whether the diesel oxidation catalyst is deteriorated based on the temperature of the coolant, the temperature of the outside air, the temperature of the intake air, the temperature of the diesel oxidation catalyst, the fuel injection amount for soot incineration, and the target temperature of the diesel oxidation catalyst. step; and a final diagnosis step in which the control unit finally diagnoses whether the diesel oxidation catalyst is deteriorated based on the diagnosis results of the first degradation diagnosis unit and the diagnosis results of the second degradation diagnosis unit.

Here, the first diagnosis step includes determining a current threshold value based on a map in which threshold values corresponding to the RPM of the engine and the amount of fuel consumed by the engine are recorded; And if the target temperature of the diesel oxidation catalyst minus the current temperature of the diesel oxidation catalyst is less than the determined threshold, it may include diagnosing that deterioration has occurred in the diesel oxidation catalyst.

In addition, the second diagnosis step is performed when the temperature of the coolant exceeds the first reference value, the temperature of the outside air exceeds the second reference value, the temperature of the intake air exceeds the third reference value, and the current diesel oxidation catalyst is set at the target temperature. If the value minus the temperature of the oxidation catalyst is greater than the critical value, the fuel injection amount for exhaust incineration is within the first critical range, and the target temperature of the diesel oxidation catalyst is within the second critical range, it can be diagnosed that deterioration has occurred in the diesel oxidation catalyst. .

Additionally, in the final diagnosis step, if any one of the first degradation diagnosis unit and the second degradation diagnosis unit diagnoses deterioration, it can be finally diagnosed that deterioration has occurred in the diesel oxidation catalyst.

Additionally, in the final diagnosis step, deterioration of the diesel oxidation catalyst can be diagnosed in the standard regeneration mode among engine operation modes.

The device and method for diagnosing the deterioration of the diesel oxidation catalyst according to an embodiment of the present invention can diagnose the deterioration of the diesel oxidation catalyst with high accuracy by diagnosing the deterioration of the diesel oxidation catalyst in consideration of the operating conditions of the vehicle.

1 is an example diagram of an exhaust gas purification system to which an embodiment of the present invention is applied;
Figure 2 is a diagram illustrating the operation of an exhaust gas purification system to which an embodiment of the present invention is applied.
3 is a configuration diagram of a deterioration diagnosis device for a diesel oxidation catalyst according to an embodiment of the present invention;
4 is a detailed configuration diagram of a first deterioration diagnosis unit provided in a deterioration diagnosis device for a diesel oxidation catalyst according to an embodiment of the present invention;
5 is a detailed configuration diagram of a second deterioration diagnosis unit provided in the deterioration diagnosis device for a diesel oxidation catalyst according to an embodiment of the present invention;
Figure 6 is a performance analysis diagram of a deterioration diagnosis device for diesel oxidation catalyst according to an embodiment of the present invention;
7 is a flowchart of a method for diagnosing deterioration of a diesel oxidation catalyst according to an embodiment of the present invention;
Figure 8 is a block diagram showing a computing system for executing a method for diagnosing deterioration of a diesel oxidation catalyst according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through illustrative drawings. When adding reference numerals to components in each drawing, it should be noted that identical components are given the same reference numerals as much as possible even if they are shown in different drawings. Additionally, when describing embodiments of the present invention, if detailed descriptions of related known configurations or functions are judged to impede understanding of the embodiments of the present invention, the detailed descriptions will be omitted.

In describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, or order of the component is not limited by the term. Additionally, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted in an ideal or excessively formal sense unless explicitly defined in the present application. No.

1 is an exemplary diagram of an exhaust gas purification system to which an embodiment of the present invention is applied.

In Figure 1, the HCI (HydroCarbon Injection) module injects fuel (diesel) heated to a high temperature to burn exhaust fumes.

DOC (Diesel Oxidation Catalyst) is a diesel oxidation catalyst device that oxidizes soluble organic substances among carbon monoxide, hydrocarbons, and PM emitted from diesel vehicles and purifies them into carbon dioxide and water that are harmless to the human body.

DPF (Diesel Particulate Filter) is a smoke filtration device that physically collects and combusts PM in the exhaust gas generated from the engine of a diesel vehicle. Diesel engines without a DPF emit soot.

T1 is located on the inlet side of the DOC and measures the temperature.

T2 is located on the outlet side of DOC and measures temperature.

The differential pressure sensor measures the pressure difference between the input and output ends of the DPF.

The ECU (Engine Control Unit) performs overall control so that each of the above components can perform their functions normally.

Figure 2 is a diagram illustrating the operation of an exhaust gas purification system to which an embodiment of the present invention is applied.

As shown in Figure 2, the collection section is a section that collects soot within the DPF, and the ECU (Engine Control Unit) collects soot based on the differential pressure sensor and soot model mounted at the front and rear of the DPF. Predict the amount of sedimentation.

The temperature increase section is a section in which the engine's exhaust gas temperature is forcibly raised. The ECU uses the intake throttle valve and EGR (Exhaust gas recirculation) valve to maintain the temperature of the DOC at the exothermic reaction temperature (for example, 300 degrees) to maintain the HCI. Control spraying. At this time, the ECU can control retarded injection, post injection, etc.

The regeneration section is a section where accumulated soot is burned, and the target temperature is maintained by the exothermic reaction of DOC caused by HCI injection. DOC performance diagnosis is performed in the regeneration section.

Figure 3 is a configuration diagram of a deterioration diagnosis device for a diesel oxidation catalyst according to an embodiment of the present invention.

As shown in FIG. 3, the deterioration diagnosis device 100 of a diesel oxidation catalyst according to an embodiment of the present invention includes a first deterioration diagnosis unit 10, a second deterioration diagnosis unit 20, and a control unit 30. ) may include. At this time, depending on the method of implementing the diesel oxidation catalyst deterioration diagnosis device 100 according to an embodiment of the present invention, each component may be combined with each other and implemented as one, or some components may be omitted.

Looking at each of the above components, first, the first deterioration diagnosis unit 10 works in conjunction with the ECU (Engine Control Unit, 200) to determine the temperature of the diesel oxidation catalyst, the RPM (Revolution Per Minute) of the engine, the amount of fuel consumed by the engine, etc. can be collected, or, as shown in FIG. 4, a separate module can be provided to obtain the temperature of the diesel oxidation catalyst, the RPM of the engine, and the amount of fuel consumed by the engine.

The first deterioration diagnosis unit 10 determines the current threshold value based on a map in which threshold values corresponding to the RPM of the engine and the amount of fuel consumed by the engine are recorded, and sets the current temperature of the diesel oxidation catalyst from the target temperature of the diesel oxidation catalyst. If the subtracted value is less than the above-determined threshold, it can be diagnosed that deterioration has occurred in the diesel oxidation catalyst. At this time, the first deterioration diagnosis unit 10 obtains the RPM of the engine obtained through the RPM detector 14 and the fuel amount detector 15 on a map in which the threshold values corresponding to the RPM of the engine and the amount of fuel consumed by the engine are recorded. A threshold value corresponding to the amount of fuel consumed by one engine can be extracted. Here, deterioration indicates abnormal heat generation.

The second deterioration diagnosis unit 20 determines whether the temperature of the coolant exceeds the first standard value, the temperature of the outside air exceeds the second standard value, the temperature of the intake air exceeds the third standard value, and the current temperature of the diesel oxidation catalyst is exceeded. If the value minus the temperature of the diesel oxidation catalyst is greater than the critical value, the HCI fuel injection amount (fuel injection amount for exhaust incineration) is within the first critical range, and the target temperature of the diesel oxidation catalyst is within the second critical range, the diesel oxidation catalyst may deteriorate. It can be judged that it has occurred. Here, deterioration indicates performance degradation.

The control unit 30 performs overall control so that each of the components can perform their functions normally. This control unit 30 may be implemented in the form of hardware or software, and of course, may also be implemented in the form of a combination of hardware and software. Preferably, the control unit 30 may be implemented with a microprocessor, but is not limited thereto.

The control unit 30 can finally diagnose whether the diesel oxidation catalyst is deteriorated based on the diagnosis results of the first degradation diagnosis unit 10 and the diagnosis results of the second degradation diagnosis unit 20. That is, if the control unit 30 diagnoses that any one of the first degradation diagnosis unit 10 and the second degradation diagnosis unit 20 is deteriorated, it can finally diagnose that the diesel oxidation catalyst is deteriorated.

It is desirable for the control unit 30 to diagnose the deterioration of the diesel oxidation catalyst in the standard regeneration mode among the engine operation modes, but it is not necessarily limited to this, and the control unit 30 can diagnose the deterioration of the diesel oxidation catalyst in other engine operation modes as well. It can also be done.

For reference, the engine operation mode is as shown in [Table 1] below.

Figure 4 is a detailed configuration diagram of a first deterioration diagnosis unit provided in a deterioration diagnosis device for a diesel oxidation catalyst according to an embodiment of the present invention.

As shown in FIG. 4, the first deterioration diagnosis unit 10 provided in the deterioration diagnosis device 100 of a diesel oxidation catalyst according to an embodiment of the present invention includes a memory 11, an HCI detector 12, It may include a temperature sensor 13, an RPM detector 14, a fuel quantity detector 15, and a controller 16.

Looking at each of the above components, first, the memory 11 can store a map (or table) in which thresholds corresponding to the RPM of the engine and the amount of fuel consumed by the engine are recorded.

The memory 11 may be a flash memory type, a hard disk type, a micro type, and a card type (e.g., a Secure Digital Card (SD Card) or an eXtream Digital Card (XD Card). )), RAM (Random Access Memory), SRAM (Static RAM), ROM (Read-Only Memory), PROM (Programmable ROM), EEPROM (Electrically Erasable PROM), magnetic memory (MRAM, It may include at least one type of storage medium among magnetic RAM, magnetic disk, and optical disk types of memory.

The HCI detector 12 can detect whether HCI fuel is injected. That is, the HCI detector 12 can detect whether fuel for exhaust incineration is injected.

The temperature sensor 13 is a module corresponding to T2 in FIG. 1 and is mounted on the outlet side of the diesel oxidation catalyst to measure the temperature of the diesel oxidation catalyst.

The RPM detector 14 can detect the RPM of the engine.

The fuel amount detector 15 can detect the amount of fuel consumed by the engine.

The controller 16 performs overall control so that each of the components can perform their functions normally. This controller 16 may be implemented in the form of hardware or software, and of course, may also be implemented in the form of a combination of hardware and software. Preferably, the controller 16 may be implemented with a microprocessor, but is not limited thereto.

The controller 16 can determine whether fuel for exhaust incineration is injected through the HCI detector 12.

The controller 16 may determine the threshold at the current time based on the map stored in the memory 11. That is, the controller 16 may determine a threshold corresponding to the RPM of the engine obtained through the RPM detector 14 and the amount of fuel consumed by the engine obtained through the fuel amount detector 15 based on the map.

The controller 16 detects deterioration of the diesel oxidation catalyst if the value obtained by subtracting the temperature of the diesel oxidation catalyst measured by the temperature sensor 13 from the target temperature of the diesel oxidation catalyst while the fuel for exhaust incineration is being injected is less than the determined threshold. It can be diagnosed as having occurred.

In one embodiment of the present invention, an example is described in which the first degradation diagnosis unit 10 is equipped with the HCI detector 12, the RPM (Revolution Per Minute) detector 14, and the fuel quantity detector 15 as separate components. , the controller 16 may be implemented to directly collect engine RPM information, engine fuel consumption information, HCI status, etc. through the vehicle network. At this time, the vehicle network may include CAN (Controller Area Network), LIN (Local Interconnect Network), FlexRay, MOST (Media Oriented Systems Transport), Ethernet, etc.

Figure 5 is a detailed configuration diagram of a second deterioration diagnosis unit provided in the deterioration diagnosis device for a diesel oxidation catalyst according to an embodiment of the present invention.

As shown in FIG. 5, the second deterioration diagnosis unit 20 provided in the deterioration diagnosis device 100 of the diesel oxidation catalyst according to an embodiment of the present invention includes the HCI status determiner 21 and the DOC status determination. It may include a device 22, an operating condition determiner 23, and a controller 24.

Looking at each of the above components, first, the HCI state determiner 21 determines the warm up state of the HCI module based on the temperature of the coolant, the temperature of the outside air, and the temperature of the intake air. At this time, the warm-up state of the HCI module may mean the warm-up state of the engine.

The HCI status determiner 21 may determine that the HCI module is in a warm-up state when the temperature of the coolant exceeds the first standard value, the temperature of the outside air exceeds the second standard value, and the temperature of the intake air exceeds the third standard value.

The DOC state determiner 22 determines the current threshold value based on a map in which threshold values corresponding to the RPM of the engine and the amount of fuel consumed by the engine are recorded, and subtracts the current temperature of the diesel oxidation catalyst from the target temperature of the diesel oxidation catalyst. It may be determined whether the value is greater than the determined threshold.

The operating condition determiner 23 may determine whether the fuel injection amount for exhaust incineration is within the first critical range.

The operating condition determiner 23 can determine whether the target temperature of the diesel oxidation catalyst is within the second critical range. For reference, the target temperature of the diesel oxidation catalyst can be obtained through the vehicle network from the ECU or the exhaust purification system in the vehicle.

The controller 24 performs overall control so that each of the components can perform their functions normally. This controller 24 may be implemented in the form of hardware or software, and of course, may also be implemented in the form of a combination of hardware and software. Preferably, the controller 24 may be implemented with a microprocessor, but is not limited thereto.

The controller 24 can determine whether the diesel oxidation catalyst is deteriorated based on the temperature of the coolant, the temperature of the outside air, the temperature of the intake air, the temperature of the diesel oxidation catalyst, the HCI fuel injection amount, and the target temperature of the diesel oxidation catalyst.

That is, the controller 24 determines that the temperature of the coolant exceeds the first standard value, the temperature of the outside air exceeds the second standard value, the temperature of the intake air exceeds the third standard value, and the current diesel oxidation temperature is set at the target temperature of the diesel oxidation catalyst. If the value minus the temperature of the catalyst is greater than the critical value, the HCI fuel injection amount is within the first critical range, and the target temperature of the diesel oxidation catalyst is within the second critical range, it can be determined that deterioration has occurred in the diesel oxidation catalyst.

Figure 6 is a performance analysis diagram of a device for diagnosing deterioration of a diesel oxidation catalyst according to an embodiment of the present invention.

In Figure 6, it can be seen that the measured temperature 611 of the diesel oxidation catalyst follows the target temperature 612 of the diesel oxidation catalyst (located within a certain range), as shown in '610' for the DOC normal product. Here, '613' represents the engine RPM, and '614' represents the amount of fuel consumed by the engine.

On the other hand, it can be seen that the measured temperature 621 of the diesel oxidation catalyst does not follow (located within a certain range) the target temperature 622 of the diesel oxidation catalyst, such as '620' for DOC deteriorated products. '630' indicates that the diesel oxidation catalyst deterioration diagnosis device 100 according to an embodiment of the invention has detected the deterioration of DOC.

Figure 7 is a flowchart of a method for diagnosing deterioration of a diesel oxidation catalyst according to an embodiment of the present invention.

First, the first deterioration diagnosis unit 10 diagnoses deterioration of the diesel oxidation catalyst by applying a variable threshold according to the RPM of the engine and the amount of fuel consumed by the engine to the difference between the current temperature and the target temperature of the diesel oxidation catalyst (701) ).

In addition, the second deterioration diagnosis unit 20 determines whether the diesel oxidation catalyst is deteriorated based on the temperature of the coolant, the temperature of the outside air, the temperature of the intake air, the temperature of the diesel oxidation catalyst, the fuel injection amount for exhaust incineration, and the target temperature of the diesel oxidation catalyst. Diagnose (702).

Thereafter, the control unit 30 makes a final diagnosis of whether the diesel oxidation catalyst is deteriorated based on the diagnosis result of the first degradation diagnosis unit 10 and the diagnosis result of the second degradation diagnosis unit 20 (703).

Figure 8 is a block diagram showing a computing system for executing a method for diagnosing deterioration of a diesel oxidation catalyst according to an embodiment of the present invention.

Referring to FIG. 8, the method for diagnosing deterioration of a diesel oxidation catalyst according to an embodiment of the present invention described above can also be implemented through a computing system. Computing system 1000 includes at least one processor 1100, memory 1300, user interface input device 1400, user interface output device 1500, storage 1600, and It may include a network interface 1700.

The processor 1100 may be a central processing unit (CPU) or a semiconductor device that processes instructions stored in the memory 1300 and/or storage 1600. Memory 1300 and storage 1600 may include various types of volatile or non-volatile storage media. For example, the memory 1300 may include Read Only Memory (ROM) and Random Access Memory (RAM).

Accordingly, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be implemented directly in hardware, software modules, or a combination of the two executed by processor 1100. The software module may be stored on a storage medium such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, solid state drive (SSD), removable disk, CD-ROM (i.e., memory 1300 and/or It may reside in storage 1600). An exemplary storage medium is coupled to processor 1100, which can read information from and write information to the storage medium. Alternatively, the storage medium may be integrated with processor 1100. The processor and storage medium may reside within an application specific integrated circuit (ASIC). The ASIC may reside within the user terminal. Alternatively, the processor and storage medium may reside as separate components within the user terminal.

The above description is merely an illustrative explanation of the technical idea of the present invention, and various modifications and variations will be possible to those skilled in the art without departing from the essential characteristics of the present invention.

Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be construed as being included in the scope of rights of the present invention.

10: First deterioration diagnosis unit
20: Second deterioration diagnosis unit
30: control unit
200: ECU

Claims (11)

a first deterioration diagnosis unit that diagnoses deterioration of the diesel oxidation catalyst by applying a variable threshold according to the RPM of the engine and the amount of fuel consumed by the engine to the difference between the current temperature and the target temperature of the diesel oxidation catalyst;
a second deterioration diagnosis unit that diagnoses whether the diesel oxidation catalyst is deteriorated based on the temperature of the coolant, the temperature of the outside air, the temperature of the intake air, the temperature of the diesel oxidation catalyst, the fuel injection amount for exhaust incineration, and the target temperature of the diesel oxidation catalyst; and
A control unit that finally diagnoses whether the diesel oxidation catalyst is deteriorated based on the diagnosis result of the first degradation diagnosis unit and the diagnosis result of the second degradation diagnosis unit,
The first deterioration diagnosis unit,
A memory in which a map in which thresholds corresponding to the RPM of the engine and the amount of fuel consumed by the engine are recorded is recorded;
A first detector that detects whether fuel for soot incineration is injected;
A temperature sensor that measures the temperature of the diesel oxidation catalyst;
a second detector that detects the RPM of the engine;
a third detector that detects the amount of fuel consumed by the engine; and
Based on the map, the current threshold corresponding to the RPM of the engine detected by the second detector and the amount of fuel consumed by the engine detected by the third detector is determined, and diesel oxidation is performed while the fuel for exhaust incineration is being injected. A controller that diagnoses that deterioration has occurred in the diesel oxidation catalyst if the value obtained by subtracting the current temperature from the target temperature of the catalyst is less than the determined threshold.
A deterioration diagnosis device for a diesel oxidation catalyst including a device.
delete delete According to claim 1,
The second deterioration diagnosis unit,
The temperature of the coolant exceeds the first standard value, the temperature of the outside air exceeds the second standard value, the temperature of the intake air exceeds the third standard value, and the target temperature of the diesel oxidation catalyst is subtracted from the current temperature of the diesel oxidation catalyst. Deterioration diagnosis of a diesel oxidation catalyst, characterized in that it is diagnosed that deterioration has occurred in the diesel oxidation catalyst if it is greater than the critical value, the fuel injection amount for exhaust incineration is within the first critical range, and the target temperature of the diesel oxidation catalyst is within the second critical range. Device.
According to claim 1,
The control unit,
A deterioration diagnosis device for a diesel oxidation catalyst, characterized in that if any one of the first deterioration diagnosis unit and the second deterioration diagnosis unit diagnoses deterioration, a final diagnosis is made that deterioration has occurred in the diesel oxidation catalyst.
According to claim 1,
The control unit,
A deterioration diagnosis device for diesel oxidation catalyst, characterized in that it diagnoses deterioration of the diesel oxidation catalyst in standard regeneration mode among engine operation modes.
A first diagnosis step in which the first deterioration diagnosis unit diagnoses whether the diesel oxidation catalyst is deteriorated by applying a variable threshold according to the RPM of the engine and the amount of fuel consumed by the engine to the difference between the current temperature and the target temperature of the diesel oxidation catalyst;
The second deterioration diagnosis unit diagnoses whether the diesel oxidation catalyst is deteriorated based on the temperature of the coolant, the temperature of the outside air, the temperature of the intake air, the temperature of the diesel oxidation catalyst, the fuel injection amount for soot incineration, and the target temperature of the diesel oxidation catalyst. step; and
A final diagnosis step in which the control unit finally diagnoses whether the diesel oxidation catalyst is deteriorated based on the diagnosis result of the first degradation diagnosis unit and the diagnosis result of the second degradation diagnosis unit,
The first deterioration diagnosis unit,
A memory in which a map in which thresholds corresponding to the RPM of the engine and the amount of fuel consumed by the engine are recorded, a first detector that detects whether fuel for exhaust incineration is injected, a temperature sensor that measures the temperature of the diesel oxidation catalyst, and an engine A second detector for detecting the RPM of the engine, a third detector for detecting the amount of fuel consumed by the engine, and based on the map, the RPM of the engine detected by the second detector and the amount of fuel consumed by the engine detected by the third detector. A controller that determines the corresponding threshold at the current time and diagnoses that deterioration has occurred in the diesel oxidation catalyst if the value obtained by subtracting the current temperature from the target temperature of the diesel oxidation catalyst while the fuel for exhaust incineration is being injected is less than the determined threshold. A method for diagnosing the deterioration of a diesel oxidation catalyst, including:
delete According to claim 7,
The second diagnostic step is,
The temperature of the coolant exceeds the first standard value, the temperature of the outside air exceeds the second standard value, the temperature of the intake air exceeds the third standard value, and the target temperature of the diesel oxidation catalyst is subtracted from the current temperature of the diesel oxidation catalyst. Deterioration diagnosis of a diesel oxidation catalyst, characterized in that it is diagnosed that deterioration has occurred in the diesel oxidation catalyst if it is greater than the critical value, the fuel injection amount for exhaust incineration is within the first critical range, and the target temperature of the diesel oxidation catalyst is within the second critical range. method.
According to claim 7,
The final diagnostic step is,
A method for diagnosing deterioration of a diesel oxidation catalyst, characterized in that if any one of the first deterioration diagnosis unit and the second deterioration diagnosis unit diagnoses deterioration, a final diagnosis is made that deterioration has occurred in the diesel oxidation catalyst.
According to claim 7,
The final diagnostic step is,
A method for diagnosing deterioration of a diesel oxidation catalyst, characterized in that it diagnoses deterioration of the diesel oxidation catalyst in the standard regeneration mode among engine operation modes.

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