Hydrocarbon accumulation estimation device, hydrocarbon accumulation estimation method, control device, and exhaust gas purification system

Abstract

The hydrocarbon accumulation estimation device includes a hydrocarbon accumulation estimation unit that estimates the amount of hydrocarbons accumulated in the exhaust gas purification device of the internal combustion engine equipped with an oxidation catalyst, based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine.

Description

Technical Field

[0001] This invention relates to a hydrocarbon accumulation estimation device, a hydrocarbon accumulation estimation method, a control device, and a waste gas purification system.

[0002] This application claims priority to Japanese Patent Application No. 2021-030520, filed on February 26, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] Patent Document 1 describes a system that estimates the amount of unburned hydrocarbons (hereinafter referred to as HC. HC is a general term for organic compounds including carbon and hydrogen) accumulated in the device constituting the exhaust aftertreatment system of an internal combustion engine, and accelerates the heating of the exhaust pipe of the exhaust aftertreatment system when the estimated result exceeds a predetermined threshold. In the system described in Patent Document 1, the mass I of HC accumulated in the exhaust pipe is calculated using the formula "I = R + PC". Here, R is the residual value, P is the mass of HC generated by the internal combustion engine (the increase or increase portion of HC), and C is the mass of HC converted by the exhaust aftertreatment system (the decrease or decrease portion of HC). It should be noted that in this system, the increase (P) of HC is calculated using a map created based on experimental data, using the internal combustion engine speed (RPM), the mass of injected fuel, the mass of intake air, and preferably the ambient temperature as parameters. Furthermore, the decrease (C) of HC is estimated based on the temperature of the device constituting the exhaust aftertreatment system.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 6650675 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In the system described in Patent Document 1, the increase in HC (P) is calculated using a mapping that takes the engine speed, the mass of injected fuel, the mass of intake air, and preferably the ambient temperature as parameters. In this case, since the only temperature-related parameter is the ambient temperature, the estimation error of the increase in HC differs depending on whether the ambient temperature is low, the engine is warm, or not. Furthermore, generally, increasing the number of parameters in the estimation process can be expected to improve the estimation accuracy; however, considering the time and effort required to develop the calculation method, it is desirable to select appropriate parameters.

[0009] The present invention was made in view of the above circumstances, and its object is to provide a hydrocarbon accumulation estimation device, a hydrocarbon accumulation estimation method, a control device, and an exhaust gas purification system that can appropriately and accurately estimate the amount of hydrocarbon (HC) accumulation.

[0010] Solution for solving the problem

[0011] To address the aforementioned issues, one aspect of the present invention is a hydrocarbon accumulation estimation device, which estimates the amount of hydrocarbons accumulated in the exhaust gas purification device of the internal combustion engine equipped with an oxidation catalyst, based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine.

[0012] Another aspect of the present invention is a method for estimating hydrocarbon accumulation, which includes the following steps: estimating the amount of hydrocarbons accumulated in the exhaust gas purification device of the internal combustion engine equipped with an oxidation catalyst, based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine.

[0013] Another aspect of the present invention is a control device comprising: a hydrocarbon accumulation estimation unit that estimates the amount of hydrocarbons accumulated in the exhaust gas purification device of the internal combustion engine equipped with an oxidation catalyst, based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine; and a temperature rise control execution unit that performs temperature rise control of the exhaust gas of the internal combustion engine.

[0014] Another aspect of the present invention is an exhaust gas purification system comprising: a control device having a hydrocarbon accumulation estimation unit and a temperature control execution unit, the hydrocarbon accumulation estimation unit estimating the amount of hydrocarbons accumulated in the exhaust gas purification device of the internal combustion engine having an oxidation catalyst based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine; the temperature control execution unit performing temperature control of the exhaust gas of the internal combustion engine; and the exhaust gas purification device.

[0015] Invention Effects

[0016] According to various methods of the present invention, the amount of hydrocarbon (HC) accumulation can be estimated appropriately and with good accuracy. Attached Figure Description

[0017] Figure 1This is a system diagram illustrating a structural example of an engine control system according to an embodiment of the present invention.

[0018] Figure 2 It means Figure 1 A block diagram illustrating an example structure of the engine control device 100.

[0019] Figure 3 It means Figure 2 The diagram shows a structural example of the environmental condition determination mapping 211.

[0020] Figure 4 It means Figure 2 The diagram shows a structural example of the HC increase estimation mapping 212 under normal control.

[0021] Figure 5 It means Figure 2 The diagram shows a structural example of the estimated HC increase mapping 213 during low-temperature control.

[0022] Figure 6 It means Figure 2 The diagram shows a structural example of the HC reduction estimate mapping 214.

[0023] Figure 7 It means Figure 2 A flowchart illustrating an example of the operation of the engine control device 100.

[0024] Figure 8 It means Figure 2 A flowchart illustrating an example of the operation of the engine control device 100.

[0025] Figure 9 It is a schematic representation Figure 1 The timing diagram shows an example of the operation of the engine control system 10.

[0026] Figure 10 It means Figure 1 A block diagram illustrating an example structure of the engine control device 100 (engine control device 100a).

[0027] Figure 11 It means Figure 10 The diagram shows a block diagram of the structure of the mapping included in the fuel injection control mapping 301.

[0028] Figure 12 It means Figure 11 The diagram shows a structural example of the injection timing control mapping 311.

[0029] Figure 13 It means Figure 11 The diagram shows a structural example of the track pressure control mapping 312.

[0030] Figure 14 It means Figure 11 The diagram shows a structural example of the pilot injection quantity control mapping 313.

[0031] Figure 15 It means Figure 11 The diagram shows a structural example of a map 314 for controlling the ignition injection period.

[0032] Figure 16 It means Figure 11 The diagram shows a structural example of a rear injection quantity control mapping 315.

[0033] Figure 17 It means Figure 10 A flowchart illustrating an example of the operation of the engine control device 100a.

[0034] Figure 18 It means Figure 1 A block diagram illustrating an example structure of the engine control device 100 (engine control device 100b).

[0035] Figure 19 It means Figure 18 The diagram shows a structural example of the HC added portion presumed mapping 215.

[0036] Figure 20 It means Figure 18 The diagram shows a structural example of the correction gain mapping 216.

[0037] Figure 21 It means Figure 18 A flowchart illustrating an example of the operation of the engine control device 100b.

[0038] Figure 22 It is used for explanation Figure 1 The diagram illustrates an example of the operation of the engine control system 10. Detailed Implementation

[0039] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that in the various figures, the same reference numerals are used for the same or corresponding structures, or reference numerals with the English letters "a" or "b" appended to the end of the same reference numerals are used to appropriately omit the description.

[0040] <First Implementation Method>

[0041] (Engine Control System 10)

[0042] Figure 1This is a system diagram illustrating a structural example of an engine control system 10, which is a structural example of an exhaust gas purification system according to various embodiments of the present invention. Figure 1 The engine control system 10 shown includes an engine 1, a turbocharger 2, an exhaust passage 3, an exhaust gas purification device 4, a monitor 8, an engine control unit 100, an engine coolant temperature sensor 91, an intake manifold temperature sensor 92, and an engine rotation sensor 93. It should be noted that... Figure 1 In the engine control system 10 or engine control device 100 of this embodiment, the main structures shown are those related to the function of estimating the amount of HC (hydrocarbon) accumulation in the exhaust gas purification device 4. Structures related to other functions such as fuel injection control are omitted from the illustration as appropriate.

[0043] Engine 1 is a structural example of an internal combustion engine, and in this embodiment, it is a multi-cylinder diesel engine. Turbocharger 2 is a turbocharger that uses the exhaust gas of engine 1 to compress the intake air of engine 1. Exhaust passage 3 discharges the exhaust gas of engine 1 into the atmosphere through exhaust gas purification device 4.

[0044] The exhaust gas purification device 4 is a device for purifying nitrogen oxides (NOx) and particulate matter (PM) contained in the exhaust gas of engine 1, and includes a DPF device 5, an SCR device 6, a heating device 7, a temperature sensor 94, and a temperature sensor 95 installed in the exhaust passage 3 of engine 1. The DPF device 5 includes a DOC (Diesel Oxidation Catalyst) 51 and a DPF (Diesel Particulate Filter) 52. The DPF 52 captures PM, and the nitrogen dioxide converted by the DOC 51 oxidizes the PM captured downstream into carbon dioxide, thus removing the PM. The SCR device 6 includes an SCR (Selective Catalytic Reduction) 61, a pump 62 that supplies urea water to the exhaust gas upstream of the SCR 61, and a tank 63, which converts nitrogen oxides (NOx) into nitrogen molecules (N2) and water (H2O).

[0045] It should be noted that diesel engine exhaust contains HC (hydrocarbons) in addition to NOx and PM. In the low-load operating range (approximately 200 degrees Celsius or less upstream of the exhaust gas purification device 4), HC accumulates in DOC51, DPF52, and SCR61. If this condition persists for an extended period, the HC accumulation continues to increase. Therefore, if the engine is subsequently operated at a high load, the temperature inside the exhaust gas purification device 4 rises, causing the accumulated HC to burn rapidly, potentially damaging the device. Therefore, if the low-load operating range (approximately 200 degrees Celsius or less upstream of the exhaust gas purification device 4) persists for an extended period, and if a certain amount of HC has accumulated (but not to the point of posing a risk of damage), it is necessary to periodically raise the exhaust temperature to release the accumulated HC.

[0046] The heating device 7 includes, for example, a fuel injection device or burner, a heater, and an exhaust valve that throttles the exhaust passage 3, and raises the exhaust temperature upstream of DOC51. The heating device 7 is controlled by the engine control unit 100 to raise the exhaust temperature in the exhaust gas purification device 4 to the target temperature in order to remove PM generated in the operating area of ​​engine 1 from the DPF52 and urea precipitates (solid substances) from urea water from the exhaust passage 3, or to release HC accumulated in DOC51, DPF52, and SCR6I.

[0047] Additionally, temperature sensor 94 measures the inlet temperature of DOC 51 and outputs the result to engine control unit 100. Temperature sensor 95 measures the outlet temperature of DOC 51 and outputs the result to engine control unit 100. The measured values ​​of temperature sensor 94 and temperature sensor 95 are examples of a fourth measured value corresponding to the temperature within the exhaust gas purification device 4. Either temperature sensor 94 or temperature sensor 95 may be omitted. The fourth measured value is not limited to the inlet or outlet temperature of DOC 51 and may be the temperature of other components.

[0048] The monitor 8 has, for example, a display panel and an input panel, and functions as a display device and an input device. It displays specified text and images according to the instructions of the engine control device 100, or outputs signals corresponding to the input operations of the user (operator) to the engine control device 100.

[0049] The engine coolant temperature sensor 91 measures the temperature of the engine coolant (hereinafter referred to as engine coolant temperature), which is the coolant of the engine 1, and outputs the measured result to the engine control unit 100. The measured value of the engine coolant temperature sensor 91 is an example of a second measured value corresponding to the temperature of the coolant in the engine 1.

[0050] The intake manifold temperature sensor 92 measures the temperature of the gas flowing in the intake manifold (not shown) of the engine 1 (hereinafter referred to as the intake manifold temperature), and outputs the measured result to the engine control unit 100. The measured value of the intake manifold temperature sensor 92 is an example of a first measured value corresponding to the intake air temperature of the engine 1.

[0051] The engine rotation sensor 93 measures the rotational speed (speed of rotation) of the crankshaft of the engine 1 (hereinafter referred to as engine speed) and outputs the measured result to the engine control unit 100. The measured value of the engine rotation sensor 93 is an example of a third measured value corresponding to the exhaust gas flow rate of the engine 1. It should be noted that the third measured value can also be the value obtained by measuring the exhaust gas flow rate itself.

[0052] The engine control unit 100 repeatedly inputs analog or digital sensor signals from multiple sensors, including the engine coolant temperature sensor 91, the intake manifold temperature sensor 92, and the engine rotation sensor 93, at a predetermined cycle. It then uses the multiple injectors provided with the engine 1 to control fuel injection, control various motors and valves, control the automatic heating device 7 (hereinafter referred to as automatic regeneration) to control the release of HC accumulated in the exhaust gas purification device 4, or control the release of HC after fixing the engine speed based on a manual indication (hereinafter referred to as fixed manual regeneration).

[0053] The stationary manual regeneration is controlled as follows: Under normal operating conditions (a state where normal operation can be performed without fixing the engine speed to a certain speed), if the exhaust temperature does not rise sufficiently, and PM or urea deposits are not removed or HC cannot be released, normal operation is stopped with the user's permission, restoring the performance of the exhaust gas purification device 4. In stationary manual regeneration, the engine control unit 100 first uses the monitor 8 to request the user that stationary manual regeneration is possible or that it is necessary to perform stationary manual regeneration. Conversely, when the user issues an instruction to perform stationary manual regeneration using the monitor 8, the engine control unit 100 fixes the engine speed to a certain speed, causing the exhaust temperature to rise, thus removing PM or urea deposits and releasing HC.

[0054] It should be noted that in fuel injection control, the engine control unit 100 defines different control states based on at least two temperatures in low-temperature control and normal control. In low-temperature control, fuel injection control suitable for low temperatures is performed, and in normal control, fuel injection control suitable for temperatures higher than low temperatures, such as normal temperatures, is performed.

[0055] (Structural example of engine control unit 100)

[0056] Reference Figures 2-6 ,right Figure 1 The structure of the engine control device 100 shown will be described using an example. Figure 2 It means Figure 1 A block diagram illustrating an example structure of the engine control device 100. Figure 3 It means Figure 2 The diagram shows a structural example of the environmental condition determination mapping 211. Figure 4 It means Figure 2 The diagram shows a structural example of the HC increase estimation mapping 212 under normal control. Figure 5 It means Figure 2 The diagram shows a structural example of the estimated HC increase mapping 213 during low-temperature control. Figure 6 It means Figure 2 The diagram shows a structural example of the HC reduction estimate mapping 214.

[0057] Figure 2 The engine control device 100 shown can be constructed using, for example, a computer such as a microcomputer, peripheral circuitry of the computer, and peripheral devices. As a functional structure composed of hardware such as the computer and software such as programs executed by the computer, it possesses... Figure 2 The diagram shows multiple modules. It should be noted that... Figure 2 This refers to the functional structure among the multiple functional structures of the engine control unit 100, which is used to estimate the amount of HC accumulated in the exhaust gas purification device 4, and the functional structure for controlling the release of HC based on the estimated amount of HC accumulated.

[0058] Figure 2 The engine control device 100 shown includes an environmental condition determination unit 101, an HC accumulation estimation unit 102, an HC release control start determination unit 103, a temperature rise control execution unit 104, a notification instruction unit 105, an engine speed fixation control execution unit 106, an HC release control stop determination unit 107, and a storage unit 108. Furthermore, the storage unit 108 includes an HC storage accumulation estimation mapping 201. The HC accumulation estimation mapping 201 includes an environmental condition determination mapping 211, an HC increase estimation mapping 212 during normal control, an HC increase estimation mapping 213 during low temperature control, and an HC decrease estimation mapping 214.

[0059] It should be noted that the estimation of HC accumulation using mapping 201 or other mappings described later can be made based on, for example, experimental results or simulation results from actual machines.

[0060] The environmental condition determination unit 101 determines the environmental conditions based on the intake manifold temperature and engine coolant temperature using the environmental condition determination mapping 211. Here, environmental conditions are the main factors occurring around the engine 1 that affect the amount of HC emitted by the engine 1 (or the exhaust temperature of the engine 1). In this embodiment, environmental conditions are defined by whether the engine 1's fuel injection control is in low-temperature control or normal control mode. Figure 3 This is a structural example representing the environmental condition determination mapping 211. Figure 3 The environmental condition determination mapping 211 shown is a mapping that uses intake manifold temperature and engine coolant temperature as parameters to define environmental conditions (whether it is low temperature control or normal control). Figure 3 The environmental condition determination mapping 211 shown sets the horizontal axis to engine coolant temperature and the vertical axis to intake manifold temperature, defining the environmental conditions corresponding to engine coolant temperature and intake manifold temperature. It should be noted that for engine coolant temperature, values ​​to the right of "0" are positive, and values ​​to the left are negative; for intake manifold temperature, values ​​above "0" are positive, and values ​​below "0" are negative.

[0061] The HC accumulation estimation unit 102 calculates the estimated value of HC accumulation in the exhaust gas purification device 4 by repeatedly performing the following formula at a predetermined calculation cycle.

[0062] Estimated HC accumulation amount [g] = Estimated HC accumulation amount [g] calculated from the previous calculation + Increase in HC [g] + Decrease in HC [g]

[0063] Among them, the estimated value of HC accumulation [g] and the increase of HC [g] have 0 or positive values, and the decrease of HC [g] has 0 or negative values.

[0064] The HC accumulation estimation unit 102 first estimates the HC increase based on the environmental conditions, engine speed, and DOC temperature determined by the environmental condition determination unit 101, using the HC increase estimation mapping 212 under normal control or the HC increase estimation mapping 213 under low temperature control. Then, based on the engine speed and DOC temperature, it estimates the HC decrease using the HC decrease estimation mapping 214. Next, the HC accumulation estimation unit 102 calculates the HC accumulation estimation value by adding the HC increase and HC decrease calculated in the previous calculation cycle to the current calculation. It should be noted that the DOC temperature is, for example, the inlet temperature of DOC51 measured by temperature sensor 94, the outlet temperature of DOC51 measured by temperature sensor 95, or a calculated value (average, etc.) from the inlet and outlet temperatures of DOC51.

[0065] Figure 4This is a structural example representing the HC increase estimation mapping 212 (first correspondence information) under normal control. The HC increase estimation mapping 212 under normal control uses engine speed and DOC temperature as parameters, and defines the environmental conditions as the HC increase per unit time [mg / s] under normal control. When the HC accumulation estimation unit 102 determines that the environmental conditions are under normal control, it uses the HC increase estimation mapping 212 under normal control to obtain the HC increase per unit time [mg / s] corresponding to engine speed and DOC temperature, and can calculate the HC increase [g] by multiplying the HC increase per unit time by the calculation period [s].

[0066] Figure 5 This section presents a structural example of the HC increase estimation mapping 213 (first correspondence information) under low-temperature control. The HC increase estimation mapping 213 under low-temperature control uses engine speed and DOC temperature as parameters, defining the environmental condition as the HC increase per unit time [mg / s] under low-temperature control. When the HC accumulation estimation unit 102 determines that the environmental condition is low-temperature control, it uses the HC increase estimation mapping 213 under low-temperature control to obtain the HC increase per unit time [mg / s] corresponding to engine speed and DOC temperature, and calculates the HC increase [g] by multiplying the HC increase per unit time by the calculation period [s].

[0067] Figure 6 This is a structural example representing the HC reduction estimation mapping 214 (second correspondence information). The HC reduction estimation mapping 214 uses engine speed and DOC temperature as parameters to define the HC reduction per unit time [mg / s]. The HC accumulation estimation unit 102 uses the HC reduction estimation mapping 214 to obtain the HC reduction per unit time [mg / s] corresponding to engine speed and DOC temperature, and can calculate the HC reduction [g] by multiplying the HC reduction per unit time by the calculation period [s].

[0068] The HC emission control start determination unit 103 compares the estimated HC accumulation amount calculated by the HC accumulation amount estimation unit 102 with a predetermined determination value. If the estimated HC accumulation amount is above the determination value, it determines that HC emission control is to begin. In HC emission control, automatic regeneration and scheduled manual regeneration are performed in stages. The determination value is, for example, set to a value that allows for a margin of safety to prevent damage caused by the accumulation of HC in the exhaust gas purification device 4.

[0069] When the heating control execution unit 104 determines that the HC release control start determination unit 103 has started HC release control, it controls the heating device 7 to perform automatic regeneration.

[0070] The notification instruction unit 105 uses the monitor 8 to issue notifications indicating that a scheduled manual regeneration is possible, requests to perform scheduled manual regeneration, or permission to perform scheduled manual regeneration from a user. At this time, the notification instruction unit 105 may issue a first notification instruction and a second notification instruction in stages, for example. The first notification instruction requests the execution of scheduled manual regeneration, but the level of the request is lower than that of the second notification instruction. For example, the first notification instruction may request that the scheduled manual regeneration be performed at a time convenient to the user. The second notification instruction requests the execution of scheduled manual regeneration, but the level of the request is higher than that of the first notification instruction. For example, the second notification instruction may request that the scheduled manual regeneration be performed immediately. Furthermore, during the period from the execution of temperature control (S203) to the first notification instruction, it is also possible to notify the user of the status that scheduled manual regeneration is possible from the monitor 8 for a certain period of time.

[0071] When the notification instruction unit 105 accepts permission from the user to perform fixed engine speed control, the engine speed fixed control execution unit 106 performs fixed engine speed control.

[0072] The HC release control stop determination unit 107 determines whether the accumulated HC has been released (or reduced to a specified amount). If it has been released (or reduced to a specified amount), it stops the HC release control.

[0073] (Example of engine control unit 100 operation)

[0074] Reference Figures 7-9 ,right Figure 2 The operation of the engine control device 100 shown will be explained using an example. Figure 7 and Figure 8 It means Figure 2 A flowchart illustrating an example of the operation of the engine control device 100. Figure 9 It is a schematic representation Figure 1 The timing diagram shows an example of the operation of the engine control system 10.

[0075] First, refer to Figure 7 ,right Figure 2 The process of handling the estimated HC accumulation in the engine control device 100 shown is explained. Figure 7 The process shown is executed repeatedly at a specified calculation cycle. When Figure 7At the start of the process, the environmental condition determination unit 101 reads the intake manifold temperature, engine coolant temperature, engine speed, and DOC temperature (step S101). Next, the environmental condition determination unit 101 selects the environmental condition (normal control or low temperature control) using the environmental condition determination mapping 211 based on the intake manifold temperature and engine coolant temperature (step S102). Next, if the environmental condition is determined to be under normal control (if "yes" in step S103), the HC accumulation estimation unit 102 estimates the HC increase amount under normal control using the HC increase estimation mapping 212 based on the engine speed and DOC temperature (step S104). On the other hand, if the environmental condition is determined to be under low temperature control (if "no" in step S103), the HC accumulation estimation unit 102 estimates the HC increase amount under low temperature control using the HC increase estimation mapping 213 based on the engine speed and DOC temperature (step S105).

[0076] After step S104 or S105, the HC accumulation estimation unit 102 estimates the HC reduction based on engine speed and DOC temperature using the HC reduction estimation mapping 214 (step S106). Next, the HC accumulation estimation unit 102 estimates the HC accumulation based on the HC accumulation estimation value calculated from the previous calculation process, the HC increase, and the HC decrease (calculating the HC accumulation estimation value) (step S107), and then ends. Figure 7 The processing shown.

[0077] Next, refer to Figure 8 , Figure 2 The engine control device 100 shown describes the process of controlling the release of HC based on the estimated value of HC accumulation. Figure 8 The process shown begins upon startup of the engine control unit 100. Figure 8 When the process begins, the HC emission control start determination unit 103 obtains the estimated HC accumulation value estimated by the HC accumulation estimation unit 102 (step S201) and determines whether the estimated HC accumulation value is above the determination value (step S202). If the estimated HC accumulation value is not above the determination value (if it is "No" in step S202), the HC emission control start determination unit 103 obtains the estimated HC accumulation value estimated by the HC accumulation estimation unit 102 again after a certain period of time (step S201).

[0078] On the other hand, if the estimated HC accumulation value is above the judgment value (if "Yes" is true in step S202), the temperature rise control execution unit 104 starts temperature rise control through automatic regeneration (step S203). Next, the notification instruction unit 105 executes a first notification instruction from the monitor 8 (step S204). Next, the notification instruction unit 105 determines whether there is a response indicating that a request for fixed manual regeneration has been accepted from the monitor 8 in response to the first notification instruction (step S205). If there is a response indicating that a request for fixed manual regeneration has been accepted from the monitor 8 (if "Yes" is true in step S205), the engine speed fixed control execution unit 106 executes engine speed fixed control (step S206).

[0079] On the other hand, if there is no response from the monitor 8 indicating an intention to accept the request for scheduled manual regeneration (if "No" is received in step S205), the notification instruction unit 105 determines whether a certain period of time has elapsed since the first notification instruction was issued (step S207). If no certain period of time has elapsed and there is no response indicating an intention to accept the request for scheduled manual regeneration (if "No" is received in both step S207 and step S205), the notification instruction unit 105 repeatedly executes the determination in step S205 and step S207.

[0080] If a certain amount of time has elapsed (if "Yes" is received in step S207), the notification instruction unit 105 executes a second notification instruction from the monitor 8 (step S208). Next, the notification instruction unit 105 determines whether there is a response indicating that a request for fixed manual regeneration has been accepted from the monitor 8 in response to the second notification instruction (step S209). If there is a response indicating that a request for fixed manual regeneration has been accepted from the monitor 8 (if "Yes" is received in step S209), the engine speed fixed control execution unit 106 executes engine speed fixed control (step S206). If there is no response indicating that a request for fixed manual regeneration has been accepted from the monitor 8 (if "No" is received in step S209), the notification instruction unit 105 performs a repeat of the determination process of step S209 (from "No" in step S209 to the repetition of step S209).

[0081] After step S206, the HC release control stop determination unit 107 obtains the estimated HC accumulation amount value estimated by the HC accumulation amount estimation unit 102 (step S210) and determines whether the accumulated HC has been released (step S211). If the accumulated HC has not been released (if "No" is true in step S211), the HC release control stop determination unit 107 obtains the estimated HC accumulation amount value estimated by the HC accumulation amount estimation unit 102 again after a certain period of time (step S210). On the other hand, if the accumulated HC has been released (if "Yes" is true in step S211), the HC release control stop determination unit 107 stops the HC release control (step S212) and ends the process. Figure 8 The processing shown.

[0082] It should be noted that, Figure 8 The processing flow shown is an example and can be modified appropriately. For example, if the determination in step S209 is repeatedly "no", the HC release control stop determination unit 107 can repeatedly obtain the estimated value of HC accumulation and determine whether the accumulated HC has been released. If it is determined that HC has been released, the second notification instruction is withdrawn, and the processing returns to step S201. For example, it can handle the situation where HC is released due to changes in operating status such as an increase in DOC temperature. In addition, the HC increase estimation mapping 212 during normal control, the HC increase estimation mapping 213 during low temperature control, and the HC decrease estimation mapping 214, which are examples of the first correspondence information, are not limited to mapping. They can also be configured as mathematical formulas that calculate the HC increase and HC decrease using engine speed and DOC temperature as parameters. In this case, the mathematical formula is also an example of the first and second correspondence information.

[0083] (Function, Effect)

[0084] Figure 9 Examples illustrating the time-varying values ​​of HC buildup, engine speed, DOC temperature, intake manifold temperature, and engine coolant temperature. For example... Figure 9 As shown, if engine 1 operates at time t1 and remains in a low-load state (low exhaust temperature) until time t2, the estimated HC accumulation gradually increases. From time t2 to time t3, as engine 1 changes from a low-load state to a higher-load state, the estimated HC accumulation gradually decreases from time t2 to time t3. Figure 9In the example shown, compared to normal conditions, the estimated increase rate of HC accumulation is higher under low-temperature control, thus decreasing from time t2. However, at time t3, the accumulation is still greater than under normal control. Furthermore, when the engine returns to a low-load state at time t3, the estimated HC accumulation increases again under low-temperature control. Figure 9 In the example shown, the decision value is exceeded at time t4.

[0085] For example, when the estimated HC accumulation is low in accuracy, it is necessary to significantly increase the margin relative to the judgment value (e.g., to compare with the judgment value accordingly for the case with the largest error). Although this is a reference example, as... Figure 22 As shown, the DOC input HC inflow varies considerably in dependence on engine speed depending on the outside air temperature. If a high-precision estimation of the accumulation amount corresponding to this change in dependence can be performed, the margin of error relative to the judgment value can be reduced. That is, with high estimation accuracy, the margin of error relative to the judgment value can be reduced compared to low accuracy. In this case, with high estimation accuracy, the error between the actual time exceeding the judgment value and the time when it is determined to have exceeded the judgment value based on the estimation value can be reduced. Therefore, by improving estimation accuracy, the time until the control accompanying the stabilization of engine speed can be delayed. Therefore, with higher accuracy, the time during which normal operation can be sustained can be extended compared to the case of low estimation accuracy. It should be noted that... Figure 22 It is used for explanation Figure 1 The diagram illustrates an example of the operation of the engine control system 10, and shows the relationship between engine speed and the DOC input HC inflow.

[0086] According to this embodiment, the engine control device 100 (hydrocarbon accumulation estimation device) includes an HC (hydrocarbon) accumulation estimation unit 102. This HC (hydrocarbon) accumulation estimation unit 102 estimates the amount of HC (hydrocarbon) accumulated in the exhaust gas purification device 4 of the internal combustion engine equipped with an oxidation catalyst based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine. Therefore, it is possible to estimate the amount of hydrocarbon (HC) accumulation appropriately and with good accuracy.

[0087] Furthermore, according to this embodiment, the engine control device 100 (hydrocarbon accumulation estimation device) also includes a storage unit 108. This storage unit 108 stores first correspondence information relating a third measured value indicating the environmental conditions of the internal combustion engine, a fourth measured value corresponding to the temperature inside the exhaust gas purification device 4, and a first correspondence information relating the increase in HC accumulation in the exhaust gas purification device 4. When estimating the accumulation amount, the HC accumulation estimation unit 102 estimates the increase based on the environmental conditions of the internal combustion engine determined according to the first and second measured values, the third measured value, the fourth measured value, and the first correspondence information. According to this structure, the increase in hydrocarbon (HC) can be estimated appropriately and with good accuracy using the first correspondence information corresponding to the environmental conditions that can be constructed using mapping, simple calculation formulas, etc.

[0088] Furthermore, according to this embodiment, the storage unit 108 also stores second correspondence information representing the correspondence between the third and fourth measured values ​​and the reduction in HC accumulated in the exhaust gas purification device 4. When estimating the accumulation amount, the HC accumulation estimation unit 102 estimates the reduction based on the third and fourth measured values ​​and the second correspondence information. With this structure, the increase in hydrocarbon (HC) can be estimated appropriately and with good accuracy using first correspondence information corresponding to environmental conditions that can be constructed using mapping, simple calculation formulas, etc. With this structure, the decrease in hydrocarbon (HC) can be estimated appropriately and with good accuracy using second correspondence information that can be constructed using mapping, simple calculation formulas, etc.

[0089] <Second Implementation Method>

[0090] Next, refer to Figures 10-17 The second embodiment of the present invention will now be described. Figure 10 It means Figure 1 A block diagram illustrating an example structure of the engine control device 100 (represented as engine control device 100a). Figure 11 It means Figure 10 The diagram shown is a block diagram of a structural example of a fuel injection control map 301. Figure 12 It means Figure 11 The diagram shows a structural example of the injection timing control mapping 311. Figure 13 It means Figure 11 The diagram shows a structural example of the track pressure control mapping 312. Figure 14 It means Figure 11 The diagram shows a structural example of the ignition injection quantity control mapping 313. Figure 15 It means Figure 11 The diagram shows a structural example of a map 314 for controlling the ignition injection period. Figure 16 It means Figure 11The diagram shows a structural example of a rear injection quantity control mapping 315. Figure 17 It means Figure 10 A flowchart illustrating an example of the operation of the engine control device 100a.

[0091] In the second embodiment, Figure 1 The basic structure of the engine control system 10 shown is the same as that in the first embodiment. In the second embodiment, it is similar to... Figure 2 The structure corresponding to the engine control device 100 shown is... Figure 10 The structure of the engine control device 100a shown is similar to Figure 2 The engine control unit 100 shown has a slightly different structure. That is, in Figure 2 In the engine control device 100 shown, the environmental condition determination unit 101 uses the environmental condition determination mapping 211 to determine environmental conditions. In contrast, in... Figure 10 In the engine control device 100a shown, the environmental condition determination unit 101a uses the fuel injection control mapping 301 to determine environmental conditions. Figure 10 In the engine control device 100a shown, the HC accumulation estimation mapping 201a stored in the storage unit 108 does not include the environmental condition determination mapping 211. Additionally, the storage unit 108 newly stores a fuel injection control mapping 301.

[0092] like Figure 11 As shown, Figure 10 The fuel injection control mapping 301 shown includes: an injection timing control mapping 311, a rail pressure control mapping 312, an ignition injection quantity control mapping 313, an ignition injection period control mapping 314, and a post-injection quantity control mapping 315 used by the engine control device 100a in fuel injection control.

[0093] like Figure 12As shown, the injection timing control mapping 311 includes an environmental condition determination mapping 3111, a normal control mapping 3112, and a low-temperature control mapping 3113. The environmental condition determination mapping 3111 defines the environmental conditions using engine coolant temperature and intake manifold temperature as parameters. In this case, the environmental conditions are defined in three states: normal control, low-temperature control, and interpolation control. The normal control mapping 3112 and the low-temperature control mapping 3113 define the injection timing [SOI BTDC deg] of the main injection during normal control and the injection timing [SOI BTDC deg] of the main injection during low-temperature control, using engine speed [rpm] and the main injection quantity [mg / st] as parameters. Here, "st" is the stroke, and "SOI BTDC deg" is the angle before top dead center at the start of injection. The main injection quantity is determined, for example, based on the output signal of an accelerator sensor (not shown).

[0094] The engine control unit 100a determines the environmental conditions based on the engine coolant temperature and intake manifold temperature using environmental condition determination mapping 3111. Furthermore, when the environmental conditions are under normal control, the engine control unit 100a uses normal control mapping 3112 to determine the injection timing based on engine speed and the main injection quantity. When the environmental conditions are under low temperature control, the engine control unit 100a uses low temperature control mapping 3113 to determine the injection timing based on engine speed and the main injection quantity. Finally, when the environmental conditions are under interpolation control, the engine control unit 100a uses both normal control mapping 3112 and low temperature control mapping 3113, based on engine speed and the main injection quantity, as the result of interpolation processing (interpolation processing) using the values ​​of normal control mapping 3112 and low temperature control mapping 3113, to determine the injection timing.

[0095] In addition, such as Figure 13 As shown, the rail pressure control mapping 312 includes an environmental condition determination mapping 3121, a normal control mapping 3122, and a low-temperature control mapping 3123. The environmental condition determination mapping 3121 defines the environmental conditions using engine coolant temperature and intake manifold temperature as parameters. In this case, the environmental conditions are defined using three states of interpolation control in addition to normal control and low-temperature control. The normal control mapping 3122 and the low-temperature control mapping 3123 define the rail pressure (common rail pressure) [bar] for normal control and the rail pressure [bar] for low-temperature control using engine speed [rpm] and main injection quantity [mg / st] as parameters.

[0096] The engine control unit 100a determines the environmental conditions based on the engine coolant temperature and intake manifold temperature using environmental condition determination mapping 3121. Furthermore, when the environmental conditions are under normal control, the engine control unit 100a determines the rail pressure based on engine speed and main injection quantity using normal control mapping 3122. When the environmental conditions are under low temperature control, the engine control unit 100a determines the rail pressure based on engine speed and main injection quantity using low temperature control mapping 3123. Finally, when the environmental conditions are under interpolation control, the engine control unit 100a determines the rail pressure based on engine speed and main injection quantity, using both normal control mapping 3122 and low temperature control mapping 3123, as the result of interpolation processing (interpolation processing) using the values ​​of normal control mapping 3122 and low temperature control mapping 3123.

[0097] In addition, such as Figure 14 As shown, the ignition injection quantity control mapping 313 includes an environmental condition determination mapping 3131, a normal control mapping 3132, and a low-temperature control mapping 3133. The environmental condition determination mapping 3131 defines the environmental conditions using engine coolant temperature and intake manifold temperature as parameters. In this case, the environmental conditions are defined using three states of interpolation control in addition to normal control and low-temperature control. The normal control mapping 3132 and the low-temperature control mapping 3133 define the ignition injection quantity [mg / st] for normal control and the ignition injection quantity [mg / st] for low-temperature control, using engine speed [rpm] and main injection quantity [mg / st] as parameters.

[0098] The engine control unit 100a determines the environmental conditions based on the engine coolant temperature and intake manifold temperature using environmental condition determination mapping 3131. Furthermore, when the environmental conditions are under normal control, the engine control unit 100a uses normal control mapping 3132 to determine the ignition injection quantity based on engine speed and the main injection quantity. When the environmental conditions are under low temperature control, the engine control unit 100a uses low temperature control mapping 3133 to determine the ignition injection quantity based on engine speed and the main injection quantity. Finally, when the environmental conditions are under interpolation control, the engine control unit 100a uses both normal control mapping 3132 and low temperature control mapping 3133, based on engine speed and the main injection quantity, as the result of interpolation processing (interpolation processing) using the values ​​of normal control mapping 3132 and low temperature control mapping 3133, to determine the ignition injection quantity.

[0099] In addition, such as Figure 15As shown, the control mapping 314 during ignition injection includes an environmental condition determination mapping 3141, a normal control mapping 3142, and a low-temperature control mapping 3143. The environmental condition determination mapping 3141 defines the environmental conditions using engine coolant temperature and intake manifold temperature as parameters. In this case, the environmental conditions are defined in three states: normal control, low-temperature control, and interpolation control. The normal control mapping 3142 and the low-temperature control mapping 3143 define the ignition injection period [msec] during normal control and the ignition injection period [msec] during low-temperature control, using engine speed [rpm] and main injection quantity [mg / st] as parameters.

[0100] The engine control unit 100a determines the environmental conditions based on the engine coolant temperature and intake manifold temperature using an environmental condition determination mapping 3141. Furthermore, when the environmental conditions are under normal control, the engine control unit 100a uses a normal control mapping 3142 to determine the ignition injection period based on engine speed and the main injection quantity. When the environmental conditions are under low temperature control, the engine control unit 100a uses a low temperature control mapping 3143 to determine the ignition injection period based on engine speed and the main injection quantity. Finally, when the environmental conditions are under interpolation control, the engine control unit 100a uses both the normal control mapping 3142 and the low temperature control mapping 3143, based on engine speed and the main injection quantity, as the result of interpolation processing (interpolation processing) using the values ​​of the normal control mapping 3142 and the low temperature control mapping 3143, to determine the ignition injection period.

[0101] In addition, such as Figure 16 As shown, the post-injection quantity control mapping 315 includes an environmental condition determination mapping 3151, a normal control mapping 3152, and a low-temperature control mapping 3153. The environmental condition determination mapping 3151 defines the environmental conditions using engine coolant temperature and intake manifold temperature as parameters. In this case, in addition to normal environmental condition control and low-temperature control, three states of interpolation control are defined. The normal control mapping 3152 and the low-temperature control mapping 3153 define the post-injection quantity [mg / st] for normal control and the post-injection quantity [mg / st] for low-temperature control, respectively, using engine speed [rpm] and the main injection quantity [mg / st] as parameters.

[0102] The engine control unit 100a determines the environmental conditions based on the engine coolant temperature and intake manifold temperature using environmental condition determination mapping 3151. Furthermore, when the environmental conditions are under normal control, the engine control unit 100a uses normal control mapping 3152 to determine the post-injection quantity based on engine speed and the main injection quantity. When the environmental conditions are under low-temperature control, the engine control unit 100a uses low-temperature control mapping 3153 to determine the post-injection quantity based on engine speed and the main injection quantity. Finally, when the environmental conditions are under interpolated control, the engine control unit 100a uses both normal control mapping 3152 and low-temperature control mapping 3153, based on engine speed and the main injection quantity, and determines the post-injection quantity as the result of interpolation processing (interpolation processing) using the values ​​of normal control mapping 3152 and low-temperature control mapping 3153.

[0103] Next, refer to Figure 17 ,right Figure 10 The process of handling the estimated HC accumulation in the engine control device 100a shown will be explained. Figure 17 The process shown is executed repeatedly at a specified calculation cycle. If starting... Figure 17 In the process described, the environmental condition determination unit 101a reads the intake manifold temperature, engine coolant temperature, engine speed, and DOC temperature (step S301). Next, based on the intake manifold temperature and engine coolant temperature, the environmental condition determination unit 101a determines whether normal control is achieved in each of the following operating condition parameters (P1) to (P5) (step S302). Here, parameter (P1) is the injection timing, parameter (P2) is the rail pressure, parameter (P3) is the ignition injection quantity, parameter (P4) is the ignition injection period, and parameter (P5) is the post-injection quantity.

[0104] Next, for each operating condition parameter (P1) to (P5), if all environmental conditions are determined to be under "normal control" (if "yes" in step S303), the HC accumulation estimation unit 102 estimates the HC increase amount under normal control using the HC increase estimation mapping 212 based on engine speed and DOC temperature (step S304). On the other hand, if it is determined that none of the environmental conditions are under normal control (if "no" in step S303), the HC accumulation estimation unit 102 estimates the HC increase amount under low temperature control using the HC increase estimation mapping 213 based on engine speed and DOC temperature (step S305).

[0105] After step S304 or S305, the HC accumulation estimation unit 102 estimates the HC reduction based on engine speed and DOC temperature using the HC reduction estimation mapping 214 (step S306). Next, the HC accumulation estimation unit 102 estimates the HC accumulation based on the HC accumulation estimation value calculated from the previous calculation process, the HC increase, and the HC decrease (calculating the HC accumulation estimation value) (step S307), and then ends. Figure 17 The processing shown.

[0106] Reference Figure 8 The processing described is common to both the first and second embodiments.

[0107] According to this embodiment, the engine control device 100 (hydrocarbon accumulation estimation device) includes an HC (hydrocarbon) accumulation estimation unit 102. This HC (hydrocarbon) accumulation estimation unit 102 estimates the amount of HC (hydrocarbon) accumulated in the exhaust gas purification device 4 of the internal combustion engine equipped with an oxidation catalyst based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine. Therefore, it is possible to estimate the amount of hydrocarbon (HC) accumulation appropriately and with good accuracy.

[0108] Furthermore, in this embodiment, environmental conditions include at least one of the main factors related to fuel injection control of the internal combustion engine: injection timing, rail pressure, ignition injection quantity, ignition injection period, and post-injection quantity. Therefore, environmental conditions can be defined as conditions suitable for fuel injection control.

[0109] <Third Implementation Method>

[0110] Next, refer to Figures 18-21 The third embodiment of the present invention will now be described. Figure 18 It means Figure 1 A block diagram illustrating an example structure of the engine control device 100 (represented as engine control device 100b). Figure 19 It means Figure 18 The diagram shows a structural example of the HC added portion presumed mapping 215. Figure 20 It means Figure 18 The diagram shows a structural example of the correction gain mapping 216. Figure 21 It means Figure 18 A flowchart illustrating an example of the operation of the engine control device 100b.

[0111] In the third embodiment, Figure 1 The basic structure of the engine control system 10 shown is the same as that of the first embodiment. In the third embodiment, it is similar to... Figure 2The structure corresponding to the engine control device 100 shown is... Figure 18 The structure of the engine control device 100b shown is similar to Figure 2 The engine control unit 100 shown has a slightly different structure. That is, in Figure 2 In the engine control device 100 shown, the environmental condition determination unit 101 determines the environmental conditions; in contrast, in Figure 18 The environmental condition determination unit 101 is omitted from the engine control device 100b shown. Additionally, in Figure 18 In the engine control device 100b shown, the HC accumulation estimation mapping 201b stored in the storage unit 108 includes an HC reduction estimation mapping 214, an HC increase estimation mapping 215, and a correction gain mapping 216.

[0112] The HC reduction estimation mapping 214 is the same as in the first embodiment. For example... Figure 19 As shown, the HC increase estimation mapping 215 (first correspondence information) defines the estimated value [mg / s] of the HC increase portion using engine coolant temperature and intake manifold temperature as parameters. Additionally, the correction gain mapping 216 (correction information) defines the gain that corrects the estimated value of the HC increase portion defined by the HC increase estimation mapping 215 using engine speed as a parameter.

[0113] The HC accumulation estimation unit 102b uses engine coolant temperature and intake manifold temperature as parameters and employs HC increase estimation mapping 215 to determine the estimated value of HC increase. Next, the HC accumulation estimation unit 102b uses engine speed as a parameter and employs correction gain mapping 216 to determine the gain value. Furthermore, the HC accumulation estimation unit 102b calculates the HC increase by multiplying the determined gain by the estimated value of HC increase. It should be noted that the HC increase may, for example, be the value of the increase corresponding to the decrease calculated by HC decrease estimation mapping 214 and the decrease value calculated for each calculation cycle. Similar to the HC accumulation estimation unit 102, the HC accumulation estimation unit 102b calculates the estimated HC accumulation value based on the estimated HC accumulation value, HC increase, and HC decrease calculated from the previous calculation process.

[0114] For example, with an engine coolant temperature of 20°C, an intake manifold temperature of -20°C, and an engine speed of 1000 rpm, the HC increases by 24 mg / s × 1.3 = 31.2 mg / s.

[0115] Next, refer to Figure 21 ,right Figure 18 The process of handling the estimated HC accumulation in the engine control device 100b shown is explained. Figure 21The process shown is executed repeatedly at a specified calculation cycle. When Figure 21 At the start of the process, the HC accumulation estimation unit 102b reads in the intake manifold temperature, engine coolant temperature, engine speed, and DOC temperature (step S401). Next, the HC accumulation estimation unit 102b uses the engine coolant temperature and intake manifold temperature as parameters, employs the HC increase estimation mapping 215 to determine the HC increase, and uses the engine speed as a parameter, employs the correction gain mapping 216 to determine the gain value, and calculates the corrected HC (step S402). Next, the HC accumulation estimation unit 102b estimates the HC decrease using the HC decrease estimation mapping 214 (step S403). Next, the HC accumulation estimation unit 102b estimates the HC accumulation based on the HC accumulation estimation value, HC increase, and HC decrease calculated from the previous calculation process (calculating the HC accumulation estimation value) (step S404), and then ends the process. Figure 21 The processing shown.

[0116] According to this embodiment, a storage unit 108 is provided, which stores first correspondence information representing the correspondence between a first measured value, a second measured value, and the increase in hydrocarbon accumulation in the exhaust gas purification device 4, and correction information based on a third measured value for the first correspondence information. When estimating the accumulation amount, the HC accumulation amount estimation unit 102b corrects the value estimated based on the first measured value, the second measured value, and the first correspondence information based on the third measured value and the correction information, thereby estimating the increase. According to this structure, compared with the first embodiment, the estimation of the HC increase can be performed more simply.

[0117] The embodiments of the invention have been described above with reference to the accompanying drawings. However, the specific structure is not limited to the above embodiments, and design changes that do not depart from the scope of the invention are also possible. Furthermore, in the above embodiments, part or all of the program executed by the computer can be distributed via a computer-readable recording medium or communication line.

[0118] Industrial availability

[0119] According to various methods of the present invention, the amount of hydrocarbon (HC) accumulation can be estimated appropriately and with good accuracy.

[0120] Explanation of reference numerals in the attached figures

[0121] 1… Engine (internal combustion engine); 2… Turbocharger; 3… Exhaust passage; 4… Exhaust gas purification device; 5… DPF device; 51… DOC, 52… DPF; 6… SCR device; 7… Heating device; 8… Monitor; 10… Engine control system (exhaust gas purification system); 91… Engine coolant temperature sensor; 92… Intake manifold temperature sensor; 93… Engine rotation sensor; 94, 95… Temperature sensors; 100, 100a, 100b… Engine control unit; 101, 101a… Environmental condition assessment unit; 102, 102b… HC accumulation amount Estimation section; 104… Heating control execution section; 108… Storage section; 201, 201a, 201b… HC accumulation estimation mapping; 211… Environmental condition determination mapping; 212… HC increase estimation mapping during normal control (first correspondence information); 213… HC increase estimation mapping during low temperature control (first correspondence information); 214… HC decrease estimation mapping (second correspondence information); 215… HC increase portion estimation mapping (first correspondence information); 216… Correction gain mapping (correction information); 301… Fuel injection control mapping.

Claims

1. A device for estimating hydrocarbon accumulation, wherein, The hydrocarbon accumulation estimation device includes: The hydrocarbon accumulation estimation unit estimates the amount of hydrocarbons accumulated in the exhaust gas purification device of the internal combustion engine equipped with an oxidation catalyst, based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine. as well as The storage unit stores first correspondence information that corresponds to the third measured value based on the environmental conditions of the internal combustion engine, the fourth measured value corresponding to the temperature inside the exhaust gas purification device, and the increase in the amount of hydrocarbons accumulated in the exhaust gas purification device. When estimating the hydrocarbon accumulation amount, the hydrocarbon accumulation estimation unit estimates the increase based on the environmental conditions of the internal combustion engine determined based on the first and second measured values, the third and fourth measured values, and the first correspondence information. The environmental conditions at least define whether the fuel injection control of the internal combustion engine is low-temperature control or normal control. The first correspondence information includes at least two types: correspondence information used when the fuel injection control is a low-temperature control and correspondence information used when the fuel injection control is a normal control.

2. The hydrocarbon accumulation estimation device according to claim 1, wherein, The environmental conditions include key factors related to at least one of injection timing, rail pressure, ignition injection quantity, ignition injection period, and post-injection quantity, which are related to the fuel injection control of the internal combustion engine.

3. The hydrocarbon accumulation estimation device according to claim 1 or 2, wherein, The storage unit also stores second correspondence information representing the correspondence between the third measured value, the fourth measured value, and the amount of hydrocarbon reduction accumulated in the exhaust gas purification device. When estimating the amount of hydrocarbon accumulation, the hydrocarbon accumulation estimation unit estimates the amount of reduction based on the third measured value, the fourth measured value, and the second correspondence information.

4. A method for estimating hydrocarbon accumulation, wherein, The method for estimating hydrocarbon accumulation includes the following steps: The amount of hydrocarbons accumulated in the exhaust gas purification device of the internal combustion engine equipped with an oxidation catalyst is estimated based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine. as well as The storage unit stores first correspondence information, which represents the relationship between the third measured value based on the environmental conditions of the internal combustion engine, the fourth measured value corresponding to the temperature inside the exhaust gas purification device, and the increase in the amount of hydrocarbons accumulated in the exhaust gas purification device. In the step of estimating the amount of hydrocarbon accumulation, the increase is estimated based on the environmental conditions of the internal combustion engine determined based on the first and second measured values, the third and fourth measured values, and the first correspondence information. The environmental conditions at least define whether the fuel injection control of the internal combustion engine is low-temperature control or normal control. The first correspondence information includes at least two types: correspondence information used when the fuel injection control is a low-temperature control and correspondence information used when the fuel injection control is a normal control.

5. A control device, wherein, The control device includes: The hydrocarbon accumulation estimation unit estimates the amount of hydrocarbons accumulated in the exhaust gas purification device of the internal combustion engine equipped with an oxidation catalyst, based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine. The storage unit stores first correspondence information that corresponds to the third measured value based on the environmental conditions of the internal combustion engine, the fourth measured value corresponding to the temperature inside the exhaust gas purification device, and the increase in the amount of hydrocarbons accumulated in the exhaust gas purification device. as well as The temperature control actuator performs temperature control on the exhaust gas from the internal combustion engine. When estimating the hydrocarbon accumulation amount, the hydrocarbon accumulation estimation unit estimates the increase based on the environmental conditions of the internal combustion engine determined based on the first and second measured values, the third and fourth measured values, and the first correspondence information. The environmental conditions at least define whether the fuel injection control of the internal combustion engine is low-temperature control or normal control. The first correspondence information includes at least two types: correspondence information used when the fuel injection control is a low-temperature control and correspondence information used when the fuel injection control is a normal control.

6. A waste gas purification system, comprising: A control device comprising a hydrocarbon accumulation estimation unit, a storage unit, and a temperature control execution unit, wherein the hydrocarbon accumulation estimation unit estimates the amount of hydrocarbons accumulated in the exhaust gas purification device of the internal combustion engine equipped with an oxidation catalyst, based at least on a first measured value corresponding to the intake air temperature of the internal combustion engine, a second measured value corresponding to the temperature of the coolant of the internal combustion engine, and a third measured value corresponding to the exhaust gas flow rate of the internal combustion engine; the storage unit stores first correspondence information representing the correspondence between the third measured value, a fourth measured value corresponding to the temperature within the exhaust gas purification device, and the increase in the amount of hydrocarbons accumulated in the exhaust gas purification device, according to the environmental conditions of the internal combustion engine; and the temperature control execution unit executes temperature control of the exhaust gas of the internal combustion engine. The exhaust gas purification device, in, In the control device, When estimating the hydrocarbon accumulation amount, the hydrocarbon accumulation estimation unit estimates the increase based on the environmental conditions of the internal combustion engine determined based on the first and second measured values, the third and fourth measured values, and the first correspondence information. The environmental conditions at least define whether the fuel injection control of the internal combustion engine is low-temperature control or normal control. The first correspondence information includes at least two types: correspondence information used when the fuel injection control is a low-temperature control and correspondence information used when the fuel injection control is a normal control.

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