Deterioration estimation device

Abstract

To provide a deterioration estimating device capable of estimating the degree of deterioration of exhaust system components of an internal combustion engine with high accuracy.SOLUTION: A deterioration estimating device has: a calculation unit that calculates the amount of damage caused by at least one of fatigue and creep of exhaust system components of an internal combustion engine; an acquisition unit that acquires the temperature of the exhaust system components; a correction unit that corrects the amount of damage based on the change rate over time of the temperature of the exhaust system components; and an estimation unit that estimates the degree of deterioration of the exhaust system components from the amount of damage corrected based on the change rate over time.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a deterioration estimation device. [Background technology]

[0002] For example, exhaust system components of an engine, such as an exhaust manifold, deteriorate due to fatigue and creep caused by distortion caused by the high heat of exhaust gas emitted from the engine. Regarding the deterioration of engine exhaust system components, for example, Patent Document 1 describes a method for predicting the lifespan of exhaust system components based on the relationship between stress and strain obtained from an image of the three-dimensional shape of the object to be measured and the temperature distribution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-1455 Summary of the Invention [Problem to be solved by the invention]

[0004] However, fatigue and creep of exhaust system components change depending on the operating conditions of the engine, making it difficult to accurately predict the degree of deterioration while taking these changes into account. This problem also exists in internal combustion engines other than those used in automobiles.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a deterioration estimation device that can estimate the degree of deterioration of exhaust system parts of an internal combustion engine with high accuracy. [Means for solving the problem]

[0006] The deterioration estimation device of the present invention comprises: an acquisition unit for acquiring temperatures of exhaust system components of an internal combustion engine; Exhaust system parts It is a repeated stress caused by distortion due to thermal expansion or contraction. fatigue The first damage amount is calculated from the difference between the maximum and minimum values ​​of the temperature within a certain period, and is the deformation of the exhaust system component due to the continuous action of a force at a specific temperature. Cree P evening No. 2 The amount of damage , the temperature and the time the temperature has continued A calculation unit that calculates ,before The rate of change of temperature of the exhaust system components over time By multiplying by the nth power (n: positive real number) The aforementioned No. 1 Damage Amount and the second damage amount of each a correction unit for correcting the By the correction unit The amended No. 1 Damage Amount and by summing the second damage amount and an estimation unit that estimates the degree of deterioration of the exhaust system component. [Effects of the Invention]

[0007] According to the present invention, the degree of deterioration of exhaust system components of an internal combustion engine can be estimated with high accuracy. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram illustrating an example of a vehicle system. [Figure 2] FIG. 1 is a configuration diagram illustrating an example of an ECU (Electronic Control Unit). [Figure 3] 10 is a flowchart illustrating an example of processing by an ECU. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1 is a configuration diagram showing an example of a vehicle system 9. The vehicle system 9 is mounted on, for example, a hybrid vehicle, and includes an ECU 1, an engine 2, a motor generator (MG) 5, a power transmission device 30, axles 31, drive wheels 32, a multi-information display (display) 40, a wireless communication device 41, a vehicle speed sensor 42, an outside air temperature sensor 43, an air flow meter 44, an air-fuel ratio sensor 45, and an accelerator opening sensor 46.

[0010] The engine 2 is an example of an internal combustion engine. The engine 2 is, for example, a gasoline engine, but may also be a diesel engine. The engine 2 has an engine body (ENG) 20, spark plugs 21, an intake manifold 22, an intake pipe 23, an exhaust manifold (exhaust manifold) 24, an exhaust pipe 25, a fuel injection valve 26, and a throttle valve 27.

[0011] Air drawn in from the outside flows through the intake pipe 23. An air flow meter 44 and a throttle valve 27 are provided in the intake pipe 23. The air flow meter 44 detects the flow rate of air per unit time in the intake pipe 23. The air flow meter 44 outputs the detected value to the ECU 1. The throttle valve 27 is provided downstream of the air flow meter 44 and adjusts the flow rate of air in the intake pipe 23 in accordance with a control signal from the ECU 1. The intake manifold 22 introduces air from the intake pipe 23 into combustion chambers for each cylinder inside the engine body 20, which includes a cylinder head and a cylinder block.

[0012] The fuel injection valve 26 and the spark plug 21 are provided in the engine body 20. The fuel injection valve 26 injects fuel into the combustion chamber in accordance with a control signal from the ECU 1. The spark plug 21 ignites the mixture of fuel and air in the combustion chamber at a timing instructed by the ECU 1 for each combustion cycle.

[0013] The exhaust manifold 24 introduces the post-combustion air-fuel mixture (exhaust) from each cylinder discharged from the engine body 20 into the exhaust pipe 25. The exhaust flows through the exhaust pipe 25, where it is purified by a catalyst (not shown) before being discharged to the outside. An air-fuel ratio sensor 45 is provided in the exhaust pipe 25. The air-fuel ratio sensor 45 detects the air-fuel ratio of the exhaust. The output torque of the engine 2 and the motor-generator 5 is output to a power transmission device 30. The power transmission device 30 includes a transmission, a torque converter, a differential gear, etc., and transmits each output torque to an axle 31. Drive wheels 32 rotate together with the axle 31.

[0014] Furthermore, a vehicle speed sensor 42 detects the speed of the vehicle equipped with the vehicle system 9. An outside air temperature sensor 43 detects the outside air temperature of the vehicle. An accelerator pedal position sensor 46 detects the position of an accelerator pedal (not shown). The ECU 1 collects the detection values ​​of the above-mentioned sensors.

[0015] The display 40 displays various types of vehicle-related information output from the ECU 1. The display 40 also has a touch panel function and detects touch inputs by the vehicle driver, who is the user, and outputs the information to the ECU 1. The wireless communication device 41 is compliant with, for example, Wi-Fi (registered trademark), 4G (4th Generation), or 5G (5th Generation). The wireless communication device 41 communicates with the cloud server 8 via a communication network NW such as the Internet. The cloud server 8 transmits instructions to the ECU 1, such as instructions to replace parts of the engine 2, based on information about the state of the engine 2, for example.

[0016] The ECU 1 controls the operation of the engine 2 in response to the driver's operation. For example, the ECU 1 controls the throttle valve 27, the fuel injection valve 26, and the spark plug 21 in response to the detected values ​​of a vehicle speed sensor 42, an accelerator opening sensor 46, and an air flow meter 44.

[0017] The ECU 1 also calculates the amount of damage to the exhaust manifold 24 due to fatigue and creep from the temperature of the exhaust manifold 24. Here, fatigue of the exhaust manifold 24 refers to repeated stress caused by distortion of the exhaust manifold 24 due to thermal expansion or contraction caused by temperature changes in the exhaust gas from the engine 2. Creep of the exhaust manifold 24 refers to deformation caused by the continued application of force at a certain temperature. The exhaust manifold 24 is an example of an exhaust system part of an internal combustion engine. Exhaust system parts for internal combustion engines include not only the exhaust manifold 24 but also a turbocharger and a catalytic converter (not shown).

[0018] The ECU 1 acquires the temperature of the exhaust manifold 24 and corrects the amount of damage due to fatigue and creep based on the time change rate of the acquired temperature. The ECU 1 estimates the degree of deterioration of the exhaust manifold 24 (hereinafter referred to as the deterioration level) from the corrected amount of damage. The deterioration level estimation process will be specifically described below.

[0019] 2 is a configuration diagram showing an example of the ECU 1. The ECU 1 is a computer and includes a CPU (Central Processing Unit) 10, a ROM (Read Only Memory) 11, a RAM (Random Access Memory) 12, a storage memory 13 such as a flash memory, and an input / output port 14. The CPU 10 is electrically connected to each of the above components via a bus 19.

[0020] Programs are stored in the ROM 11. The RAM 12 is a working memory. The input / output port 14 is a circuit that processes input and output of data between the CPU 10 and the display 40, wireless communication device 41, vehicle speed sensor 42, outside air temperature sensor 43, air flow meter 44, air-fuel ratio sensor 45, and accelerator opening sensor 46.

[0021] When the CPU 10 reads a program from the ROM 11, it functions as an operation management unit 100, an engine control unit 101, a detection value collection unit 102, a temperature estimation unit 103, a damage calculation unit 104, a damage correction unit 105, a deterioration estimation unit 106, and a notification unit 107. The operation management unit 100 instructs each of the above units to operate in accordance with a predetermined sequence.

[0022] The storage memory 13 also stores in advance temperature estimation map data 130, normal mode map data 131, and sport mode map data 132. The temperature estimation map data 130 is used to estimate the temperature of the exhaust manifold 24. The normal mode map data 131 is used to calculate a command value for the output torque of the engine 2 when the vehicle is running in the normal mode. The sport mode map data 132 is used to calculate a command value for the output torque of the engine 2 when the vehicle is running in the sport mode.

[0023] The normal mode and the sport mode are examples of a plurality of control modes for the engine 2. The normal mode and the sport mode differ in the rate at which the deterioration of the exhaust manifold 24 progresses. In the sport mode, the vehicle's acceleration performance is higher than in the normal mode, and the vehicle's fuel efficiency is lower than in the normal mode. Therefore, in the sport mode, the exhaust manifold 24 deteriorates more quickly due to the amount of damage caused by the exhaust gases, which are hotter than in the normal mode. Note that the types of control modes are not limited to the two types described above, and three or more types may be provided.

[0024] The detection value collecting unit 102 collects the detection values ​​from the vehicle speed sensor 42, the outside air temperature sensor 43, the air flow meter 44, the air-fuel ratio sensor 45, and the accelerator opening sensor 46 via the input / output port 14.

[0025] The engine control unit 101 is an example of a control unit. The engine control unit 101 calculates a torque command value based on one of normal mode map data 131 and sport mode map data 132 from the detected values ​​of the vehicle speed sensor 42, the air flow meter 44, and the accelerator opening sensor 46, for example. The engine control unit 101 controls the throttle valve 27, the fuel injection valve 26, and the spark plug 21 in accordance with the torque command value, for example. The engine control unit 101 selects map data according to the control mode selected by the user, for example, while the vehicle is stopped.

[0026] The temperature estimation unit 103 is an example of an acquisition unit. The temperature estimation unit 103 acquires the temperature of the exhaust manifold 24. The temperature estimation unit 103 estimates the temperature based on temperature estimation map data 130 from, for example, the detected values ​​of the vehicle speed sensor 42, the outside air temperature sensor 43, the air flow meter 44, and the air-fuel ratio sensor 45, the ignition timing of the spark plug 21, and the estimated inlet temperature of the exhaust manifold 24 on the engine main body 20 side.

[0027] Here, the estimated inlet temperature of the exhaust manifold 24 on the engine main body 20 side can be calculated by the engine control unit 101, for example, from control parameters such as the ignition timing and fuel injection amount of the engine 2. The ignition timing is acquired from control map data (not shown) of the engine control unit 101. The temperature estimation map data 130 stores average values ​​of the temperature of the exhaust manifold 24 according to the load of the engine 2, in association with detected values, etc., based on the results of a prior simulation, etc.

[0028] The symbol Ga indicates an example of the change in temperature of the exhaust manifold 24 over time in one load pattern of the engine 2. The temperature repeatedly increases and decreases depending on the load on the engine 2. The amount of damage to the exhaust manifold 24 due to fatigue and creep changes depending on the rate of change in temperature over time. Note that the temperature estimation is not limited to the above-mentioned means, and for example, a heat transfer model or a machine learning model can also be used, and the temperature may also be obtained directly using a temperature sensor.

[0029] The damage calculation unit 104 calculates the amount of damage caused by fatigue and creep (hereinafter referred to as fatigue damage amount and creep damage amount) of the exhaust manifold 24 from the temperature estimated by the temperature estimation unit 103. At this time, the damage calculation unit does not use the time change rate of the temperature of the exhaust manifold 24. The damage calculation unit 104 calculates the amount of fatigue damage and the amount of creep damage by accumulating the amount of damage within a predetermined period of time.

[0030] For example, the damage calculation unit 104 calculates the amount of fatigue damage using a predetermined calculation formula from the repeated temperature amplitude, i.e., the difference between the maximum and minimum temperature values ​​within a certain period. The damage calculation unit 104 also calculates the amount of creep damage from the temperature and the time that the temperature continues. Note that various calculation formulas can be specified in advance from the results of previous simulations, etc.

[0031] The damage correction unit 105 is also an example of a correction unit. The damage correction unit 105 corrects each amount of damage based on the time rate of change of the temperature of the exhaust manifold 24. For example, the damage correction unit 105 calculates the change value (absolute value) per unit time of the temperature estimated by the temperature estimation unit 103 as the time rate of change of the temperature. The damage correction unit 105 calculates a correction value from the time rate of change of the temperature and multiplies each amount of damage by it to correct each amount of damage. The symbol Gb indicates an example of the amount of distortion of the exhaust manifold 24 with respect to the time rate of change of the temperature. As an example, the amount of distortion increases quadratically as the time rate of change of the temperature increases.

[0032] The deterioration estimation unit 106 is an example of an estimation unit. The deterioration estimation unit 106 estimates the deterioration level of the exhaust manifold 24 from the amount of damage corrected based on the rate of change of temperature over time.

[0033] Dall=α·Df·Ff(Ddt)+β·Dc·Fc(Ddt) ···(1)

[0034] The deterioration estimation unit 106 calculates the deterioration degree Dall (%) from the above formula (1), for example. If the deterioration degree Dall is 100 (%), the exhaust manifold 24 is unusable. In formula (1), Df is the amount of fatigue damage, and Dc is the amount of creep damage. Furthermore, Ff(Ddt) and Fc(Ddt) are correction values ​​for the amount of fatigue damage Df and the amount of creep damage Dc, respectively, which are determined by the temperature change rate Ddt with time. For example, Ff(Ddt) and Fc(Ddt) are defined as the nth power of the temperature change rate Ddt with time (n: positive real number), but are not limited to this. Furthermore, the constants α and β are parameters that are determined in advance according to the design of the engine 2.

[0035] In this way, the deterioration estimation unit 106 estimates the degree of deterioration of the exhaust manifold 24 from the amount of fatigue damage and the amount of creep damage, each corrected based on the temperature change rate Ddt. This allows the deterioration estimation unit 106 to estimate the degree of deterioration with high accuracy, taking into account the temperature change rate Ddt. Note that although the deterioration estimation unit 106 estimates the degree of deterioration from both the amount of fatigue damage and the amount of creep damage, it may also estimate the degree of deterioration from just one of them.

[0036] The notification unit 107 notifies the driver of the deterioration level Dall estimated by the deterioration estimation unit 106 and each control mode of the engine 2. Specifically, the notification unit 107 instructs the display 40 to display the deterioration level Dall and the normal mode and the sport mode. The driver selects the control mode of the engine 2 from the normal mode and the sport mode. The control mode selection result is input from the display 40 to the engine control unit 101. The engine control unit 101 controls the engine 2 based on map data corresponding to the control mode selected by the driver, either the normal mode map data 131 or the sport mode map data 132. Note that the control mode can be selected, for example, while the vehicle is stopped.

[0037] In this way, the notification unit 107 notifies the driver of the control modes that differ in the deterioration level Dall and the rate at which deterioration of the exhaust manifold 24 progresses, and the engine control unit 101 controls the engine 2 in accordance with the control mode selected by the driver. Therefore, the driver can drive the engine 2 taking into consideration the deterioration level of the exhaust manifold 24. Specifically, the driver can select the sport mode by prioritizing the acceleration performance of the vehicle over the deterioration of the exhaust manifold 24, or can select the normal mode by prioritizing suppression of deterioration of the exhaust manifold 24.

[0038] Furthermore, the notification unit 107 transmits the data on the degree of deterioration to the cloud server 8 via the wireless communication device 41. Upon receiving the data on the degree of deterioration, the cloud server 8 determines whether or not replacement of the exhaust manifold 24 is necessary based on the degree of deterioration, and transmits the determination result to the wireless communication device 41 via the communication network NW. The notification unit 107 receives the determination result from the wireless communication device 41, and instructs the display 40 to display it so that the user can confirm it.

[0039] 3 is a flowchart showing an example of the processing of the ECU 1. This processing is executed repeatedly, for example, at a fixed interval. First, the operation management unit 100 determines whether the vehicle is running or not from the control state of the engine control unit 101 (step St1).

[0040] If the vehicle is traveling (Yes in step St1), the detection value collection unit 102 collects each detection value from the above-mentioned sensor devices (step St2). Next, the temperature estimation unit 103 estimates the temperature from each detection value, etc. (step St3). Next, the damage calculation unit 104 calculates the fatigue damage amount of the exhaust manifold 24 from the temperature (step St4) and further calculates the creep damage amount (step St5). Next, the damage correction unit 105 calculates the time change rate of the temperature and calculates each correction value Ff(Ddt) and Fc(Ddt) (step St6). Next, the damage correction unit 105 corrects the fatigue damage amount Df and the creep damage amount Dc using each correction value Ff(Ddt) and Fc(Ddt) (step St7). Next, the deterioration estimation unit 106 calculates the deterioration degree Dall (%) using the above formula (1) (step St8). Next, the notification unit 107 instructs the display 40 to display the deterioration degree Dall (%) (step St9). Next, the notification unit 107 transmits the data on the degree of deterioration to the cloud server 8 (step St10).

[0041] If the vehicle is stopped (No in step St1), the notification unit 107 instructs the display 40 to display the deterioration level and each control mode (step St11). Next, the notification unit 107 determines whether or not a determination result on whether replacement of the exhaust manifold 24 is necessary has been received from the cloud server 8 (step St12). If the determination result has been received (Yes in step St12), the notification unit 107 instructs the display 40 to display the determination result (step St13). If the determination result has not been received (No in step St12), the processing of step St13 is not performed.

[0042] Next, the notification unit 107 determines whether or not the driver has selected a control mode by touching the display 40 (step St14). If no control mode has been selected (No in step St14), the process of step St14 is executed again.

[0043] Furthermore, if a control mode is selected (Yes in step St14), the engine control unit 101 selects map data according to the control mode selected by the driver (step St15). Next, the engine control unit 101 controls the engine 2 based on the selected map data (step St16). In this manner, the processing of the ECU 1 is executed. [Explanation of symbols]

[0044] 1 ECU (deterioration estimation device) 2. Engine (internal combustion engine) 24 Exhaust manifold (exhaust system part) 101 Engine control unit (control unit) 103 Temperature estimation section (acquisition section) 104 Damage calculation unit (calculation unit) 105 Damage Compensation Unit (Compensation Unit) 106 Deterioration estimation section (estimation section) 107 Notification Department

Claims

1. An acquisition unit that acquires the temperature of an exhaust system component of an internal combustion engine; a calculation unit that calculates a first damage amount due to fatigue, which is repeated stress caused by distortion due to thermal expansion or thermal contraction of the exhaust system component, from the difference between the maximum and minimum values ​​of the temperature within a certain period, and calculates a second damage amount due to creep, which is deformation of the exhaust system component due to the continuous action of force at a specific temperature, from the temperature and the time that the temperature continues; a correction unit that corrects each of the first damage amount and the second damage amount by multiplying the time rate of change of the temperature of the exhaust system component by the nth power (n: positive real number); an estimation unit that estimates a degree of deterioration of the exhaust system component by summing the first damage amount and the second damage amount corrected by the correction unit, Deterioration estimation device.

2. a notification unit that notifies a user of a plurality of control modes of the internal combustion engine that differ in the degree of deterioration and the rate of progression of the deterioration; a control unit that controls the internal combustion engine in accordance with a control mode selected by the user from among the plurality of control modes, The deterioration estimation device according to claim 1 .

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