Diagnostic control device for clogging of exhaust gas clarification member

Abstract

To enable the clogging of an exhaust gas clarification member to be diagnosed without requiring addition of a sensor.SOLUTION: There is provided a diagnostic control device 60 for clogging of a catalyst converter 41 in a vehicle 1 having: an engine 10 as a driving source; an intake passage 30 having a throttle valve 31 adjusting an intake amount flowing into the engine 10; an air flow sensor 33 measuring an actual intake amount; and an exhaust passage 40 having a catalyst converter 41 clarifying exhaust gas discharged from the engine 10. The diagnostic control device 60 has an intake amount estimation portion 62 estimating the amount of intake flowing into the engine 10 on the basis of an opening of the throttle valve 31, and a determination portion 63 determining that clogging occurs at the catalyst converter 41 when a difference between an estimated intake amount estimated by the intake amount estimation portion 62 and the actual intake amount measured by the air flow sensor 33 is larger than a prescribed value.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a clogging diagnosis control device for an exhaust gas purification member. [Background technology]

[0002] Conventionally, various vehicles are equipped with an exhaust gas purification component (purification component) that purifies harmful components in exhaust gas generated by an internal combustion engine before the exhaust gas is released into the atmosphere. Continuous use of the purification component can cause the exhaust flow passage to become clogged with substances captured by the purification component, thereby impeding the flow of exhaust.

[0003] Patent Document 1 discloses an exhaust purification device in which a catalyst regeneration type particulate filter integrally carrying an oxidation catalyst is housed in a muffler of an exhaust pipe through which exhaust gas discharged from a diesel engine via an exhaust manifold flows. The exhaust purification device of Patent Document 1 is equipped with a differential pressure sensor that measures the differential pressure between the front and rear of the particulate filter, and when an abnormal increase in back pressure is confirmed based on a detection signal from the differential pressure sensor, it is determined that the particulate filter is clogged and a warning lamp is turned on. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-155916 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the exhaust purification device of Patent Document 1, it is necessary to provide an additional differential pressure sensor to determine clogging of the particulate filter, which increases costs. In addition, since it is necessary to extend the piping path to provide the differential pressure sensor, there are problems in that the layout must be redesigned for each vehicle and pressure loss increases.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to make it possible to diagnose clogging of an exhaust gas purification member without adding an additional sensor. [Means for solving the problem]

[0007] The present invention is a control device for diagnosing clogging of an exhaust gas purification member in a vehicle equipped with an internal combustion engine as a driving source, a throttle valve that adjusts the amount of intake air flowing into the internal combustion engine, an intake passage having an actual intake air amount measuring means that measures the actual intake air amount, and an exhaust passage having an exhaust gas purification member that purifies exhaust gas discharged from the internal combustion engine, and is characterized by having an intake air amount estimation means that estimates the amount of intake air flowing into the internal combustion engine based on the opening degree of the throttle valve, and a judgment means that judges that a clogging has occurred in the exhaust gas purification member when the difference between the estimated intake air amount estimated by the intake air amount estimation means and the actual intake air amount measured by the actual intake air amount measuring means is greater than a predetermined value. Effect of the Invention

[0008] According to the present invention, it is possible to diagnose clogging of an exhaust gas purification member without adding any additional sensor. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a schematic configuration of a vehicle equipped with a clogging diagnosis control device. [Diagram 2] FIG. 2 is a diagram illustrating an example of a functional configuration of a clogging diagnosis control device. [Diagram 3] 4 is a flowchart showing an example of a process of a clogging diagnosis control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The embodiment according to the present invention is a clogging diagnosis control device 60 for a catalytic converter 41 in a vehicle 1 including an engine 10 as a driving source, an intake passage 30 having a throttle valve 31 for adjusting the amount of intake air flowing into the engine 10 and an airflow sensor 33 for measuring the actual amount of intake air, and an exhaust passage 40 having a catalytic converter 41 for purifying exhaust gas discharged from the engine 10. The diagnosis control device 60 includes an intake air amount estimation unit 62 for estimating the amount of intake air flowing into the engine 10 based on the opening degree of the throttle valve 31, and a determination unit 63 for determining that clogging has occurred in the catalytic converter 41 when the difference between the estimated intake air amount estimated by the intake air amount estimation unit 62 and the actual intake air amount measured by the airflow sensor 33 is greater than a predetermined value. Therefore, clogging of the catalytic converter 41 can be diagnosed without adding a sensor such as a differential pressure sensor. EXAMPLES

[0011] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a diagram showing a schematic configuration of a vehicle 1 equipped with a clogging diagnosis control device (hereinafter, referred to as a control device) according to this embodiment. Note that Fig. 1 is simplified for the sake of convenience in explaining this embodiment, and components that are normally equipped in a vehicle are assumed to be equipped even if they are not shown in the figure. The vehicle 1 according to this embodiment includes an engine 10 as a drive source, an intake passage 30, an exhaust passage 40, an intake VVT ​​mechanism 51, an exhaust VVT mechanism 52, a notification unit 53, a control device 60, and the like.

[0012] The engine 10 is an internal combustion engine that performs a series of strokes including an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke. The engine 10 includes a piston 12 accommodated in a cylinder 11 so as to be capable of reciprocating motion, a spark plug 13 disposed in a combustion chamber 14, an intake valve 16 located between the combustion chamber 14 and an intake port 15, an exhaust valve 18 located between the combustion chamber 14 and an exhaust port 17, a crankshaft 20 to which the piston 12 is rotatably connected via a connecting rod 19, and the like.

[0013] During the intake stroke, the piston 12 descends from top dead center to bottom dead center, the intake valve 16 opens, and the exhaust valve 18 closes. As the piston 12 descends, the intake air and fuel mixture flows from the intake passage 30 into the combustion chamber 14. In the compression stroke, the piston 12 moves upward from the bottom dead center to the top dead center, and the intake valve 16 and the exhaust valve 18 close. As the piston 12 moves upward, the air-fuel mixture is compressed. During the combustion stroke, the compressed air-fuel mixture is ignited by the spark plug 13 and combusted, pushing the piston 12 downward, causing it to move from top dead center to bottom dead center. During the exhaust stroke, the piston 12 rises from the bottom dead center to the top dead center, the intake valve 16 closes, and the exhaust valve 18 opens. As the piston 12 rises, exhaust gas generated during the combustion stroke is discharged into the exhaust passage 40.

[0014] As the engine 10 repeats a series of processes, driving force is transmitted from the engine 10 via the crankshaft 20 to the drive wheels, causing the vehicle 1 to run. Note that the configuration of the engine 10 is not particularly limited, and various known engines can be applied.

[0015] The engine 10 also has a crank angle sensor 21 and an engine speed sensor 22 . The crank angle sensor 21 detects the crank angle (the rotation angle of the crankshaft 20) and transmits information about the detected crank angle to the control device 60. The control device 60 controls the ignition timing of the spark plug 13 based on the information about the crank angle detected by the crank angle sensor 21.

[0016] The engine speed sensor 22 detects the engine speed, specifically, the number of revolutions per unit time of the crankshaft 20, and transmits the detected engine speed information to the control device 60. The control device 60 uses the engine speed information detected by the engine speed sensor 22 when calculating the engine load factor. The control device 60 also estimates the amount of intake air flowing through the intake passage 30 based on the engine speed information detected by the engine speed sensor 22.

[0017] The intake passage 30 is a passage that guides intake air taken in from outside the vehicle 1 to the combustion chamber 14 via the intake port 15. The intake passage 30 is formed, for example, by an intake pipe. In the intake passage 30, a throttle valve 31 and a fuel injector 32 are arranged in this order from the upstream side.

[0018] The throttle valve 31 opens and closes to adjust the amount of intake air flowing into the engine 10. The throttle valve 31 adjusts the amount of intake air based on the control of the control device 60. Fuel injector 32 injects fuel pumped from a fuel tank into intake passage 30. Fuel injector 32 adjusts the amount of fuel injected under the control of control device 60. Note that fuel injector 32 is not limited to injecting fuel into intake passage 30, and may be configured to inject fuel into intake port 15 or combustion chamber 14.

[0019] Further, an air flow sensor 33 and a throttle opening sensor 34 are disposed in the intake passage 30 (around the intake passage 30). The airflow sensor 33 is an example of an actual intake air amount measuring means, measures information on the intake air amount, and transmits the measured information on the intake air amount to the control device 60. The airflow sensor 33 can measure the actual amount of intake air flowing through the intake passage 30 (actual intake air amount). The throttle opening sensor 34 is an example of a valve opening detection means, which detects information on the actual opening of the throttle valve 31 and transmits the detected information on the actual opening of the throttle valve to the control device 60. The control device 60 estimates the amount of intake air flowing through the intake passage 30 based on the information on the actual opening of the throttle valve 31 detected by the throttle opening sensor 34.

[0020] The exhaust passage 40 is a passage through which exhaust gas combusted in the combustion chamber 14 is exhausted to the outside of the vehicle 1 via the exhaust port 17. The exhaust passage 40 is formed of, for example, an exhaust pipe. A catalytic converter 41 is disposed in the exhaust passage 40. The catalytic converter 41 is an example of an exhaust gas purification member, and a three-way catalyst can be used. The catalytic converter 41 purifies the exhaust gas by oxidizing and reducing harmful components contained in the exhaust gas. The catalytic converter 41 using a three-way catalyst is less likely to clog than a particulate filter, but when gasoline fuel with varying properties is used, soot is generated and the converter is more likely to clog. In addition, when gas fuel is used, the combustion temperature is low, so the viscosity of deposits generated as combustion products such as engine oil is high, making the catalytic converter 41 more likely to clog. Furthermore, due to recent exhaust gas countermeasures, the lattice spacing of the catalyst carrier has become narrower, making the catalytic converter 41 more likely to clog.

[0021] The intake VVT ​​(Variable Valve Timing) mechanism 51 varies the opening and closing timing of the intake valve 16. The intake VVT ​​mechanism 51 changes the opening and closing timing of the intake valve 16 to advance or retard based on the control of the control device 60. The intake VVT ​​mechanism 51 may be of a hydraulic type or an electric type.

[0022] The exhaust VVT (Variable Valve Timing) mechanism 52 varies the opening and closing timing of the exhaust valve 18. The exhaust VVT mechanism 52 changes the opening and closing timing of the exhaust valve 18 so as to advance or retard it based on the control of the control device 60. The exhaust VVT mechanism 52 may be of a hydraulic type or an electric type.

[0023] The notification unit 53 notifies the driver when it is determined that a blockage has occurred in the catalytic converter 41. The notification unit 53 can use, for example, a display unit such as a display or a meter panel provided in the vehicle 1, a speaker, etc. Furthermore, if the vehicle 1 is provided with a car navigation system, the notification unit 53 can use the display and speaker of the car navigation system.

[0024] The vehicle 1 also includes an atmospheric pressure sensor 54 and an accelerator opening sensor 55 . The atmospheric pressure sensor 54 detects information about the atmospheric pressure, and transmits the detected information about the atmospheric pressure to the control device 60 . The accelerator opening sensor 55 detects the amount of accelerator pedal operation by the driver, and transmits information about the detected amount of operation to the control device 60.

[0025] The control device 60 controls the entire vehicle 1. For example, an ECU (Electronic Control Unit) can be used as the control device 60. The control device 60 has a CPU, a ROM, a RAM, etc. as a hardware configuration. The ROM stores programs and predetermined information for controlling the vehicle 1 and the engine 10, etc. The RAM is a work memory that temporarily stores programs and data. The CPU reads out the programs stored in the ROM, expands them in the RAM, and executes them to control the vehicle 1 and the engine 10, etc. Furthermore, the control device 60 of this embodiment diagnoses clogging of the catalytic converter 41.

[0026] FIG. 2 is a diagram illustrating an example of a functional configuration of the control device 60. As shown in FIG. The control device 60 includes a control unit 61 , an intake amount estimation unit 62 , and a determination unit 63 . The control unit 61 controls the entire vehicle 1. The control unit 61 controls the throttle valve 31 so that the throttle valve 31 has a target opening calculated based on the accelerator opening detected by the accelerator opening sensor 55. The control unit 61 also controls the fuel injector 32 so that the fuel is injected at a fuel injection amount calculated based on the engine speed detected by the engine speed sensor 22 and the intake amount detected by the airflow sensor 33, and corrected based on information from various sensors.

[0027] The intake air amount estimation unit 62 estimates the amount of intake air (estimated intake air amount) flowing into the combustion chamber 14 of the engine 10 based on the actual opening of the throttle valve 31. Specifically, the intake air amount estimation unit 62 estimates the amount of intake air based on the actual opening of the throttle valve, the engine speed, the atmospheric pressure, the advance amount of the intake valve by the intake VVT ​​mechanism 51, and the advance amount of the exhaust valve by the exhaust VVT mechanism 52. The control device 60 stores in advance map information in which an estimated basic intake air amount is associated with the actual opening of the throttle valve and the engine speed. The intake air amount estimation unit 62 calculates the basic intake air amount by referring to the map, and corrects the basic intake air amount based on information on the atmospheric pressure, the advance amount of the intake valve 16, and the advance amount of the exhaust valve 18, thereby making it possible to estimate the estimated intake air amount flowing into the engine 10.

[0028] The determination unit 63 determines whether the catalytic converter 41 is clogged based on the estimated intake air amount estimated by the intake air amount estimation unit 62 and the actual intake air amount measured by the air flow sensor 33. That is, when deposits are accumulated in the catalytic converter 41, the back pressure of the catalytic converter 41 increases and the intake air amount decreases, so that the actual intake air amount is measured lower than the estimated intake air amount. Therefore, the determination unit 63 calculates the difference between the estimated intake air amount estimated by the intake air amount estimation unit 62 and the actual intake air amount measured by the air flow sensor 33, and determines whether the calculated difference is greater than a predetermined value.

[0029] Furthermore, the determination unit 63 determines whether or not there is an abnormality in the throttle valve 31 before determining whether the catalytic converter 41 is clogged. That is, if an abnormality occurs in which the actual opening of the throttle valve 31 does not reach the target opening, the actual intake amount will be measured lower than the estimated intake amount regardless of whether or not there is a clog in the catalytic converter 41. Therefore, the determination unit 63 can suppress erroneous determination of clogging of the catalytic converter 41 by determining in advance that the cause of the actual intake amount being measured lower than the estimated intake amount is not due to an abnormality in the throttle valve 31.

[0030] Next, an example of processing by the control device 60 will be described with reference to the flowchart of Fig. 3. The flowchart of Fig. 3 is realized, for example, by the ECU, which is the control device 60, executing a program. Moreover, the flowchart of Fig. 3 is periodically and repeatedly executed when the engine 10 is started.

[0031] In S1, the determination unit 63 determines whether or not there is an abnormality in the throttle valve 31. The determination unit 63 in this embodiment acquires information on the target opening of the throttle valve 31 according to the driving situation, specifically, information on the target opening of the throttle valve 31 calculated by the control unit 61 based on the accelerator opening. The determination unit 63 also acquires information on the actual opening of the throttle valve 31 detected by the throttle opening sensor 34. The determination unit 63 determines that there is an abnormality in the throttle valve 31 when the difference between the target opening and the actual opening is equal to or greater than a predetermined opening, and determines that there is no abnormality in the throttle valve 31 when the difference is less than the predetermined opening. If it is determined that there is no abnormality in the throttle valve 31, the process proceeds to S2. On the other hand, if it is determined that there is an abnormality in the throttle valve 31, the process of the flowchart in FIG. 3 is terminated without determining whether the catalytic converter 41 is clogged in order to avoid erroneously determining that the catalytic converter 41 is clogged.

[0032] Next, in steps S2 to S4, the determination unit 63 determines whether the catalytic converter 41 is clogged. In S2, the determination unit 63 acquires information on the estimated intake air amount estimated by the intake air amount estimation unit 62 and information on the actual intake air amount measured by the air flow sensor 33. As described above, the intake air amount estimation unit 62 estimates the intake air amount based on the actual opening degree of the throttle valve 31, the engine speed, the atmospheric pressure, the advance amount of the intake valve 16, and the advance amount of the exhaust valve 18. Next, the determination unit 63 determines whether or not the difference obtained by subtracting the actual intake air amount from the estimated intake air amount is greater than a predetermined value. If it is greater than the predetermined value, the process proceeds to S3. On the other hand, if it is not greater than the predetermined value, it is determined that no clogging has occurred in the catalytic converter 41, and the process of the flowchart in FIG. 3 is terminated. The predetermined value is recorded in advance in the control device 60, and can be set by verifying the actual intake amount when the catalytic converter 41 actually becomes clogged, or by verifying it through a simulation.

[0033] In S3, the determination unit 63 determines whether a state in which the difference between the estimated intake air amount and the actual intake air amount is greater than a predetermined value has continued for a predetermined time or more. The reason for determining whether a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a suction occurs is greater than a predetermined value is determined in this manner is that a state in which a state in which a state in which a state in which a state in which a state in which a suction occurs is less than an estimated intake air amount may momentarily occur, even if the catalytic converter 41 is not clogged, is that the operating conditions of the engine 10. If a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a state in which a suction occurs is greater than a predetermined value is determined in this manner is that the catalytic converter 41 is not clogged, the process proceeds to S4. On the other hand, if a state in which ... The specified time is recorded in advance in the control device 60, and can be set by verifying the time during which the actual intake volume is less than the estimated intake volume when the catalytic converter 41 is actually clogged or not clogged, or by verifying through simulation.

[0034] In S4, the determination unit 63 determines that a clog has occurred in the catalytic converter 41. The determination unit 63 can also notify the driver that a clog has occurred in the catalytic converter 41 via the notification unit 53, thereby urging the driver to have the catalytic converter 41 inspected. If the notification unit 53 is a display unit, the notification unit 53 can notify the driver of a clog in the catalytic converter 41 by turning on a light or displaying a message. If the notification unit 53 is a speaker, the notification unit 53 can notify the driver of a clog in the catalytic converter 41 by emitting an alarm sound or a message sound.

[0035] As described above, in this embodiment, the control device 60 has a determination unit 63 that determines that a blockage has occurred in the catalytic converter 41 when the difference between the estimated intake air amount estimated by the intake air amount estimation unit 62 and the actual intake air amount measured by the air flow sensor 33 is greater than a predetermined value. With this configuration, the clogging of the catalytic converter 41 can be diagnosed without adding a sensor such as a differential pressure sensor, so that the cost of the vehicle 1 can be reduced. In particular, when diagnosing clogging of the catalytic converter 41, which rarely becomes clogged, the cost reduction effect can be further enhanced. In addition, since there is no need to extend the piping path due to the addition of a sensor such as a differential pressure sensor, there is no need to design a layout for each vehicle, and pressure loss can be reduced.

[0036] Furthermore, in this embodiment, when a state in which the difference between the estimated intake air amount and the actual intake air amount is greater than a predetermined value continues for a predetermined time or more, the determination unit 63 determines that a blockage has occurred in the catalytic converter 41. Since a state in which the actual intake air amount is less than the estimated intake air amount may occur momentarily depending on the operating conditions of the engine 10, by determining that a state in which the difference between the estimated intake air amount and the actual intake air amount is greater than a predetermined value continues for a predetermined time or more, erroneous determination of a blockage in the catalytic converter 41 can be suppressed.

[0037] In this embodiment, the determination unit 63 determines whether the catalytic converter 41 is clogged when the difference between the target opening of the throttle valve 31 according to the driving conditions and the actual opening of the throttle valve 31 detected by the throttle opening sensor 34 is less than a predetermined opening. In this way, by determining in advance whether there is an abnormality in the throttle valve 31, it is possible to eliminate abnormalities in the throttle valve 31 as a cause of the actual intake amount being measured as less than the estimated intake amount, and it is possible to suppress erroneous determination of the clogging of the catalytic converter 41. Note that the determination unit 63 may determine whether there is an abnormality in the intake valve 16 and the exhaust valve 18 in addition to the throttle valve 31, and determine whether the catalytic converter 41 is clogged when no abnormality is found in any of the valves.

[0038] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and modifications and the like are possible within the scope of the present invention. In the above embodiment, the engine 10 is a so-called reciprocating engine, but it may be a diesel engine. When the engine 10 is a diesel engine, the exhaust gas purification member may be a particulate filter. [Explanation of symbols]

[0039] 1: Vehicle 10: Engine 12: Piston 13: Spark plug 14: Combustion chamber 16: Intake valve 18: Exhaust valve 30: Intake passage 31: Throttle valve 32: Fuel injector 33: Air flow sensor 34: Throttle opening sensor 40: Exhaust passage 41: Catalytic converter 60: Control device (diagnosis control device) 61: Control unit 62: Intake amount estimation unit 63: Determination unit

Claims

1. An internal combustion engine as a drive source; an intake passage having a throttle valve for adjusting the amount of intake air flowing into the internal combustion engine and an actual intake air amount measuring means for measuring the actual intake air amount; and an exhaust passage having an exhaust gas purification member that purifies exhaust gas discharged from the internal combustion engine. an intake air amount estimating means for estimating an amount of intake air flowing into the internal combustion engine based on an opening degree of the throttle valve; a determination means for determining that a blockage has occurred in the exhaust gas purification member when a difference between an estimated intake air amount estimated by the intake air amount estimation means and an actual intake air amount measured by the actual intake air amount measurement means is larger than a predetermined value; A clogging diagnosis control device comprising:

2. The determination means is 2. The clogging diagnosis control device according to claim 1, further comprising a controller for determining whether a blockage has occurred in the exhaust gas purification member when a state in which the difference between the estimated intake air amount estimated by the intake air amount estimation means and the actual intake air amount measured by the actual intake air amount measurement means is greater than the predetermined value continues for a predetermined period of time or longer.

3. a valve opening detection means for detecting an actual opening of the throttle valve; The determination means is 3. The clogging diagnosis control device according to claim 1, further comprising a valve opening detection means for detecting a clog in the exhaust gas purification member when a difference between a target opening of the throttle valve according to a driving condition and an actual opening of the throttle valve detected by the valve opening detection means is less than a predetermined opening.

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