Control device for an internal combustion engine

Abstract

A control device of an internal combustion engine is provided. An accumulation amount of particulate matter that has accumulated in a filter is calculated. The accumulation amount is calculated based on an emission rate of particulate matter that has been emitted from the internal combustion engine to an exhaust passage and a combustion rate of particulate matter that is combusted in the filter. The accumulation amount is biased in the exhaust gas flow direction in the filter. A combustion rate calculation process calculates the combustion rate in a manner corresponding to a degree of bias of the accumulation amount in the exhaust gas flow direction.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to Japanese Patent Application No. 2024-217701, filed on December 12, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to a control device for an internal combustion engine. Background Technology

[0004] The internal combustion engine disclosed in Japanese Patent Application Publication No. 2006-257996 has an exhaust passage equipped with a filter for capturing particulate matter (PM) in the exhaust. A control device calculates the amount of PM accumulated in the filter. PM is discharged from the combustion chamber of the internal combustion engine into the exhaust passage. PM is burned in the filter. Summary of the Invention

[0005] Methods for solving problems

[0006] According to one aspect of this disclosure, a control device for an internal combustion engine is provided. The control device includes a processing circuit. The processing circuit is configured to perform a build-up amount calculation process and a combustion rate calculation process. The build-up amount calculation process calculates the build-up amount of particulate matter deposited in a filter. The filter is disposed in the exhaust passage of the internal combustion engine. The filter traps the particulate matter in the exhaust gas of the exhaust passage. The build-up amount is calculated based on the discharge rate of the particulate matter discharged from the internal combustion engine into the exhaust passage and the combustion rate of the particulate matter burned in the filter. The build-up amount deviates in the exhaust flow direction within the filter. The combustion rate calculation process calculates the combustion rate in a manner corresponding to the degree of deviation of the build-up amount in the exhaust flow direction.

[0007] Based on this structure, the estimated accuracy of the combustion rate of particulate matter in the filter can be improved.

[0008] To accurately calculate the accumulation of particulate matter, it is desirable to accurately calculate the combustion rate of particulate matter. The above structure improves upon this. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of an internal combustion engine according to one embodiment of the application of a control device.

[0010] Figure 2 This is a flowchart illustrating the steps of the combustion rate calculation process performed by the control device in this embodiment.

[0011] Figure 3It is a coordinate graph showing the relationship between the degree of deviation in the amount of material packed, the bulk density counter, the correction factor, and the amount of particulate matter burned per unit time.

[0012] Figure 4 This is a flowchart illustrating the steps of index value calculation and processing performed by the control device in this embodiment.

[0013] Figure 5 (A) ~ Figure 5 (E) is a timing diagram illustrating the operation of this implementation. Figure 5 (A) indicates the progression of the execution state of the fuel cut-off process. Figure 5 (B) indicates the shift of the bulk density counter. Figure 5 (C) represents the change in PM combustion per unit time. Figure 5 (D) represents the shift in PM emissions per unit time. Figure 5 (E) represents the shift in PM accumulation. Detailed Implementation

[0014] Figures 1-5 (E) describes one embodiment of the control device for an internal combustion engine. For example, in this embodiment, "upstream" means upstream in the direction of exhaust flow, and "downstream" means downstream in the direction of exhaust flow.

[0015] <Structure of an Internal Combustion Engine>

[0016] like Figure 1 As shown, the internal combustion engine 10, which uses gasoline as fuel, has multiple cylinders 10a. An intake passage 13 is connected to the intake port of each cylinder 10a. A throttle valve 14 is provided in the intake passage 13 to adjust the amount of air drawn in.

[0017] Each cylinder 10a has a fuel injection valve 11 installed in its combustion chamber. In the combustion chamber of each cylinder 10a, a mixture of air drawn in through the intake passage 13 and fuel injected from the fuel injection valve 11 is burned. The mixture is ignited by a spark discharge. The exhaust gas generated by the combustion of the mixture in the combustion chamber is discharged through an exhaust passage 15. The exhaust passage 15 is connected to the exhaust port of the combustion chamber.

[0018] A three-way catalyst 17 is installed in the exhaust passage 15. The three-way catalyst 17 generates water and carbon dioxide by oxidizing the hydrocarbons (HC) and carbon monoxide (CO) contained in the exhaust. The three-way catalyst 17 generates nitrogen by reducing the nitrogen oxides (NOx) contained in the exhaust.

[0019] Downstream of the three-way catalyst 17, a gasoline particulate filter (appropriately referred to as GPF) 18 is provided in the exhaust passage 15. The GPF 18 is a PM trapping filter loaded with a three-way catalyst. PM is particulate matter in the exhaust gas (appropriately referred to as PM).

[0020] The control device 100 includes a CPU 110, a memory 120, etc. By executing the programs stored in the memory 120 by the CPU 110, the control device 100 implements various controls of the internal combustion engine 10.

[0021] Detection signals of various sensors are input to the control device 100. As various sensors, for example, a crankshaft angle sensor 53 is provided near the crankshaft of the internal combustion engine 10. The control device 100 calculates the engine speed NE of the internal combustion engine 10 based on the detection signal of the crankshaft angle sensor 53. In addition, an air flow meter 54 for detecting the intake air amount GA and a water temperature sensor 55 for detecting the coolant water temperature THW are provided in the internal combustion engine 10. The coolant water temperature THW is the temperature of the coolant water of the internal combustion engine 10.

[0022] The control device 100 controls the fuel injection of the fuel injection valve 11, the opening degree of the throttle valve 14, etc. In addition, when the output required by the internal combustion engine 10 is "0", the control device 100 executes a fuel cut-off process. The fuel cut-off process stops the fuel injection from the fuel injection valve 11.

[0023] The control device 100 calculates the PM accumulation amount Ps through an accumulation amount calculation process. The PM accumulation amount Ps is the amount of PM accumulated in the GPF 18. The control device 100 performs various controls based on the PM accumulation amount Ps. For example, when the PM accumulation amount Ps becomes equal to or greater than a predetermined over-accumulation determination value α, the control device 100 reports a warning urging maintenance of the GPF 18. Maintenance is performed at a repair shop, for example, to burn and remove the PM accumulated in the GPF 18.

[0024] <Calculation of the PM accumulation amount Ps>

[0025] For example, the control device 100 acquires the engine speed NE, the filling efficiency η, and the coolant water temperature THW. The filling efficiency η is calculated by the control device 100 based on the engine speed NE and the intake air amount GA.

[0026] The control device 100 calculates the PM emission rate Pa based on the engine speed NE, the filling efficiency η, and the coolant water temperature THW. The PM emission rate Pa is the amount of PM discharged from the internal combustion engine 10 to the exhaust passage 15 per unit time.

[0027] In addition, the control device 100 calculates the PM combustion rate Pb by executing a combustion rate calculation process described later. The PM combustion rate Pb is the amount of PM burned in the GPF 18 per unit time.

[0028] The control device 100 substitutes the value obtained by subtracting the PM combustion rate Pb from the PM emission rate Pa into the update amount ΔPs. Therefore, when the PM emission rate Pa is higher than the PM combustion rate Pb, the update amount ΔPs becomes a positive value. When the PM combustion rate Pb is higher than the PM emission rate Pa, the update amount ΔPs becomes a negative value.

[0029] Next, the control device 100 updates the PM accumulation amount Ps by adding an update amount ΔPs to the currently calculated PM accumulation amount Psp. Therefore, when the PM emission rate Pa is higher than the PM combustion rate Pb, the PM accumulation amount Ps increases. On the other hand, when the PM combustion rate Pb is higher than the PM emission rate Pa, the PM accumulation amount Ps decreases. By performing this process, the PM accumulation amount Ps is calculated.

[0030] <Fire Rate Calculation and Processing>

[0031] Figure 2 This indicates the steps involved in the combustion rate calculation process performed by the control device 100. Figure 2 The series of processes shown is implemented by the CPU 110 executing a program stored in the memory 120 of the control device 100 every predetermined cycle. Appropriately, the step number is represented by a number beginning with "S".

[0032] exist Figure 2 In the series of processes shown, the control device 100 first obtains the currently calculated PM accumulation amount Psp, GPF temperature T, and intake air volume GA. The control device 100 calculates the basic combustion rate Pbb (S100) based on the currently calculated PM accumulation amount Psp, GPF temperature T, and intake air volume GA. The basic combustion rate Pbb is the base value of the PM combustion rate Pb. The currently calculated PM accumulation amount Psp, GPF temperature T, and intake air volume GA are values ​​related to the PM combustion rate. The basic combustion rate Pbb is the maximum amount of PM burned per unit time. This maximum amount of combustion is estimated based on the currently calculated PM accumulation amount Psp, GPF temperature T, and intake air volume GA. The GPF temperature T is the temperature of GPF18. The control device 100 calculates the GPF temperature T based on the internal combustion engine speed NE and the filling efficiency η. The GPF temperature T can also be detected using a sensor or the like.

[0033] After the processing of S100 is performed, the control device 100 then performs the processing of S110.

[0034] In the processing of S110, the control device 100 calculates the correction coefficient Kd based on the bulk density counter Cd. The bulk density counter Cd is an index value representing the degree of deviation of the amount of PM in the GPF18 in the exhaust flow direction. Appropriately, the degree of deviation of the bulk density indicates the degree of deviation of the amount of PM in the GPF18 in the exhaust flow direction. The degree of deviation of the bulk density when the bulk density counter Cd is small is greater than the degree of deviation of the bulk density when the bulk density counter Cd is large. In other words, when the degree of deviation of the bulk density decreases, the bulk density counter Cd increases. When the degree of deviation of the bulk density increases, the bulk density counter Cd decreases.

[0035] The correction factor Kd is a correction value used to correct for the basic flammability Pbb. The correction factor Kd is variably set based on the bulk density counter Cd. For example... Figure 3 As shown, for example, the larger the bulk density counter Cd, the larger the correction coefficient Kd. The correction coefficient Kd is greater than "0" and less than "1".

[0036] When the process of S110 is executed, the control device 100 then executes the process of S120. In the process of S120, the control device 100 calculates various correction coefficients Kn other than the correction coefficient Kd. As various correction coefficients Kn, for example, correction coefficients corresponding to the degree of degradation of GPF18 can be listed.

[0037] When processing S120 is performed, control device 100 then performs processing S130. In processing S130, control device 100 multiplies the basic combustion rate Pbb by a correction factor Kd and various correction factors Kn. Control device 100 then substitutes the multiplied value into the PM combustion rate Pb.

[0038] When the process of S130 is executed, the control device 100 terminates the execution of this process in the current cycle.

[0039] <About Bulk Density Counters>

[0040] Figure 3 and Figure 4 Explain the bulk density counter Cd.

[0041] For example, when the oxygen supply to the high-temperature GPF18 is cut off using fuel, PM burns in the upstream section of the GPF18. On the other hand, due to the oxygen consumption caused by combustion in the upstream section, PM combustion is difficult to occur in the downstream section of the GPF18. Therefore, when PM is burning, the deviation in the amount of PM accumulation in the exhaust flow direction of the GPF18 tends to increase. On the other hand, when PM is not burning, the PM discharged from the internal combustion engine 10 is captured in the GPF18, so the deviation in the amount of PM accumulation in the exhaust flow direction of the GPF18 tends to decrease.

[0042] The inventors have discovered a tendency for the PM combustion rate in GPF18 to vary depending on the degree of deviation in the deposition amount. Specifically, they found a tendency that the smaller the deviation in deposition amount, the faster the PM combustion rate in GPF18. Therefore, as Figure 3 As shown, there is a tendency for a smaller deviation in the amount of PM accumulation to result in a higher PM burnability (Pb). PM burnability (Pb) is the amount of PM burned per unit time in GPF18.

[0043] In contrast, the control device 100 of this embodiment calculates the bulk density counter Cd in a manner that the smaller the deviation in the bulk density, the larger the bulk density counter Cd becomes. The bulk density counter Cd is an index value representing the degree of deviation in the bulk density. The control device 100 calculates the correction coefficient Kd in a manner that the larger the bulk density counter Cd becomes, the larger the correction coefficient Kd becomes. Therefore, the control device 100 calculates the PM combustion rate Pb in a manner that the smaller the deviation in the bulk density, the higher the PM combustion rate Pb.

[0044] Figure 4 This indicates the order in which the index value of the bulk density counter Cd is calculated. Figure 4 The series of processes shown are implemented by the CPU 110 executing a program stored in the memory 120 of the control device 100 every predetermined cycle. The initial value of the packing density counter Cd is "0".

[0045] exist Figure 4 In the series of processes shown, the control device 100 first determines whether the PM is currently burning (S200). In the process of S200, for example, if the calculated PM accumulation amount Ps tends to decrease, the control device 100 determines that the PM is currently burning. On the other hand, if the calculated PM accumulation amount Ps does not tend to decrease, the control device 100 determines that the PM is not currently burning.

[0046] If, in the processing of S200, it is determined that PM is currently burning (S100: Yes), the control device 100 performs a process of subtracting a predetermined reduction value A from the current bulk density counter Cd (S210). A lower limit density value is set for the bulk density counter Cd. For example, the lower limit density value is "0". If the bulk density counter Cd subtracted in the processing of S210 is less than the lower limit density value, the control device 100 substitutes the lower limit density value into the bulk density counter Cd. Therefore, lower limit protection of the bulk density counter Cd is implemented.

[0047] On the other hand, if it is determined in S200 that PM is currently not burning (S100: No), the control device 100 performs a process of adding a predetermined density increment value B to the current bulk density counter Cd (S220). When the PM emission rate Pa is high, the amount of PM captured by the GPF18 increases compared to when the PM emission rate Pa is low. Therefore, when the PM emission rate Pa is high, the rate of increase in the deviation of the bulk density becomes high. Therefore, the rate of increase of the bulk density counter Cd when the PM emission rate Pa is high is preferably faster than the rate of increase of the bulk density counter Cd when the PM emission rate Pa is low. In contrast, the control device 100 of this embodiment variably sets the density increment value B so that the higher the calculated PM emission rate Pa, the greater the density increment value B. However, the density increment value B can also be a fixed value.

[0048] Furthermore, an upper limit density value is set for the bulk density counter Cd. For example, the upper limit density value is the value of the bulk density counter Cd under the following conditions: that is, the amount of PM deposited in the exhaust flow direction of GPF18 is uniform and / or the deviation in the amount of PM deposited is minimal. The upper limit density value is preset to an appropriate value through experiments, etc. If the added bulk density counter Cd in the S220 process is greater than the upper limit density value, the control device 100 substitutes the upper limit density value into the bulk density counter Cd. Therefore, upper limit protection for the bulk density counter Cd is implemented.

[0049] When either process S210 or process S220 ends, the control device 100 terminates the execution of this process in the current cycle.

[0050] <The function of this implementation method>

[0051] Figure 5 (A) ~ Figure 5 (E) indicates the function of this implementation method. Figure 5 (A) indicates the progression of the execution state of the fuel cut-off process. Figure 5 (B) indicates the shift of the bulk density counter. Figure 5 (C) represents the change in PM combustion per unit time.Figure 5 (D) represents the shift in PM emissions per unit time. Figure 5 (E) represents the shift in PM accumulation.

[0052] When combustion of the air-fuel mixture in the internal combustion engine 10 begins at time t1, as Figure 5 As shown in (D), the PM emission rate Pa increases. Therefore, as Figure 5 As shown in (E), the PM accumulation Ps increases. Due to... Figure 5 The PM accumulation amount Ps shown in (E) does not show a decreasing trend, so the control device 100 determines that the PM is currently unburned. Therefore, as Figure 5 As shown in (B), the packing density counter Cd increases.

[0053] When at time t2, as Figure 5 As shown in (D), when the PM emission rate Pa decreases, as Figure 5 As shown in (E), the PM accumulation Ps increases, and as Figure 5 As shown in (B), the rate of increase of the packing density counter Cd decreases. In other words, as... Figure 5 As shown in (D), when the PM emission rate Pa decreases, the density increment value B decreases. Therefore, as Figure 5 As shown in (B), the packing density counter Cd increases, and as... Figure 5 As shown in (B), the rate of increase of the packing density counter Cd decreases.

[0054] If the temperature of GPF18 is above the temperature required for PM combustion, and fuel cutoff is performed at time t3, PM combustion will occur in GPF18. In the case of PM combustion, when calculating the PM combustion rate Pb, as follows... Figure 5 As shown in (E), the PM accumulation Ps shows a decreasing trend. Control device 100 determines that PM is currently burning. Therefore, after time t3, as... Figure 5 As shown in (B), the bulk density counter Cd decreases. If the bulk density counter Cd decreases, the correction factor Kd also decreases. Therefore, the PM flammability Pb, corrected by multiplying by the correction factor Kd, decreases with... Figure 5 The decrease in the packing density counter Cd shown in (B) is as follows: Figure 4 As shown in (C), it is reduced.

[0055] During the execution of the fuel cutoff process, fuel injection is stopped, and therefore combustion of the air-fuel mixture does not occur. Therefore, after time t3, as... ​ As shown in (D), the PM emission rate Pa becomes "0". Therefore, as ​ As shown in (E), the amount by which the PM accumulation Ps reduces the PM combustion rate Pb.

[0056] When the fuel cutoff process is stopped at time t4, combustion of the air-fuel mixture in the internal combustion engine 10 resumes. Therefore, the PM emission rate Pa increases, and the PM accumulation Ps increases. That is, since the PM accumulation Ps does not tend to decrease, the control device 100 determines that PM is currently unburned. The bulk density counter Cd increases again.

[0057] <Effects of this implementation method>

[0058] (1) The PM combustion rate in GPF18 tends to vary depending on the degree of deviation in the amount of PM accumulation in the exhaust flow direction of GPF18. In contrast, the control device 100 of this embodiment performs a combustion rate calculation process. The combustion rate calculation process calculates the PM combustion rate Pb based on the degree of deviation in the amount of PM accumulation in the exhaust flow direction of GPF18. Therefore, compared with cases where the PM combustion rate Pb is calculated without considering the degree of deviation in accumulation, this embodiment can improve the estimation accuracy of the PM combustion rate Pb in GPF18. The estimation accuracy of PM accumulation Ps is also improved. This is because the PM accumulation Ps is calculated by the balance between the PM combustion rate Pb and the PM emission rate Pa.

[0059] (2) In the calculation of combustion rate, the PM combustion rate Pb when the deviation of the accumulation amount is small is calculated to be higher than the PM combustion rate Pb when the deviation is large.

[0060] When the deviation in packing amount is small, the PM combustion rate in GPF18 tends to be higher than that when the deviation is large. Conversely, in this embodiment, the PM combustion rate Pb when the deviation in packing amount is small is calculated to be higher than that when the deviation is large. Therefore, it is possible to appropriately calculate the PM combustion rate Pb corresponding to the degree of deviation in packing amount.

[0061] (3) The control device 100 performs an index value calculation process for the bulk density counter Cd. The bulk density counter Cd is an index value that indicates the degree of deviation of the bulk quantity. In the index value calculation process, the bulk density counter Cd under the condition of PM combustion is updated to indicate a large degree of deviation of the bulk quantity. On the other hand, the bulk density counter Cd under the condition of PM non-combustion is updated to indicate a small degree of deviation of the bulk quantity.

[0062] When oxygen is supplied to the high-temperature GPF18 via fuel cutoff, PM combustion occurs upstream of the GPF18. Because oxygen is consumed during PM combustion upstream, PM combustion is difficult to occur downstream of the GPF18. Therefore, in the case of PM combustion, there is a tendency for a large deviation in the amount of PM accumulated in the exhaust flow direction of the GPF18. On the other hand, in the case of unburned PM, the GPF18 traps PM that has already been discharged from the combustion chamber. Therefore, in the case of unburned PM, there is a tendency for a small deviation in the amount of PM accumulated in the exhaust flow direction of the GPF18.

[0063] In contrast, in this embodiment, a bulk density counter Cd is calculated. The bulk density counter Cd is an index value related to the degree of deviation in the bulk quantity. A smaller bulk density counter Cd indicates a greater degree of deviation in the bulk quantity than a larger bulk density counter Cd. In other words, when the degree of deviation in the bulk quantity decreases, the bulk density counter Cd increases.

[0064] When PM burns, the deviation in the accumulation amount increases. In this case, the bulk density counter Cd is updated in a manner that indicates an increase in the deviation in the accumulation amount. That is, when PM burns, the bulk density counter Cd is updated to decrease. On the other hand, when PM does not burn, the deviation in the accumulation amount decreases. In this case, the bulk density counter Cd is updated in a manner that indicates a decrease in the deviation. That is, when PM does not burn, the bulk density counter Cd is updated to increase. Therefore, it is possible to appropriately calculate the index value representing the deviation in the accumulation amount.

[0065] (4) The combustion rate calculation process includes the ability to calculate the basic combustion rate Pbb based on values ​​related to PM combustion rate. The basic combustion rate Pbb is the base value for combustion rate. The combustion rate calculation process also includes the ability to calculate the correction coefficient Kd based on the index value. The correction coefficient Kd is a correction value used to correct the basic combustion rate Pbb.

[0066] The bulk density counter Cd is an index value representing the degree of deviation in bulk density. There is a tendency for a smaller deviation in bulk density to result in a faster PM combustion rate. Therefore, a correction value used to correct the PM combustion rate can be calculated based on the bulk density counter Cd. In contrast, in this embodiment, the basic combustion rate Pbb is calculated based on a value related to the PM combustion rate Pb. The basic combustion rate Pbb is the base value for the PM combustion rate Pb. The correction coefficient Kd is a correction value used to correct the basic combustion rate Pbb. The correction coefficient Kd is calculated based on the bulk density counter Cd. The degree of deviation in bulk density affects the PM combustion rate. Therefore, the basic combustion rate Pbb can be corrected based on the value affecting the PM combustion rate.

[0067] (5) The PM accumulation amount Ps is calculated by the balance between the PM combustion rate Pb and the PM emission rate Pa. Assuming that the estimated accuracy of the PM combustion rate Pb is low, in order to compensate for the deviation in the estimated accuracy of the PM combustion rate Pb, a comparative example could be considered, for example, increasing the compensation term for the emission rate Pa. However, in this comparative example, the calculated PM emission rate Pa may deviate from the actual PM emission rate. As a result, depending on the situation, the estimated accuracy of the PM accumulation amount Ps may become lower. In contrast, according to this embodiment, the estimated accuracy of the PM combustion rate Pb is improved. Therefore, the compensation term can be reduced. Therefore, the calculated PM emission rate Pa is closer to the actual PM emission rate. Therefore, the estimated accuracy of the PM accumulation amount Ps is improved.

[0068] (6) According to this embodiment, the estimation accuracy of PM accumulation amount Ps is improved. Therefore, the accuracy of various controls based on PM accumulation amount Ps is also improved.

[0069] For example, in this embodiment, when the PM accumulation amount Ps reaches or exceeds the over-accumulation judgment value α, a warning is issued urging maintenance at the repair shop to remove the PM already accumulated in GPF18 through combustion. Here, there is a concern that if the estimated PM accumulation amount Ps is low, a warning might be issued prematurely and incorrectly. In this embodiment, the estimated accuracy of the PM accumulation amount Ps is improved. Therefore, the possibility of issuing an premature warning incorrectly is reduced.

[0070] <Example of Change>

[0071] This embodiment can be implemented with modifications as follows. This embodiment and the following modifications can be combined with each other within the scope of technical inconsistency.

[0072] ·exist ​ In the S200 process shown, the determination of whether PM is burning is based on the changing trend of PM accumulation Ps. However, other methods can also be used to determine whether PM is burning. For example, if the calculated PM combustion rate Pb is greater than "0", it can be determined that PM is burning. Alternatively, the determination of whether PM is burning can also be based on the internal combustion engine speed NE and the internal combustion engine load rate.

[0073] In the above embodiment, the deviation in the amount of packing when the packing density counter Cd is small is greater than the deviation when the packing density counter Cd is large. Conversely, it can also be stated that the deviation in the amount of packing when the packing density counter Cd is small is smaller than the deviation when the packing density counter Cd is large. In this modified example, by variably setting the correction coefficient Kd such that the smaller the packing density counter Cd is, the larger the correction coefficient Kd becomes, the same effect as in the above embodiment can be obtained.

[0074] • The basic combustion rate Pbb can also be calculated in a different way than the above-described implementation method.

[0075] • The PM emission rate Pa can also be calculated in a different way than the above-described implementation method.

[0076] • The location of the GPF18 in the exhaust passage 15 can be changed appropriately.

[0077] • GPF18 can also be a filter without a three-way catalyst.

[0078] The control device 100 is not limited to having a CPU and memory to perform software processing. For example, the control device 100 may also have dedicated hardware circuitry, such as an ASIC, to perform hardware processing on at least a portion of the software processing performed in the above embodiments. That is, the control device 100 may simply include a processing circuit having any of the structures in (a) to (c) below: (a) A processing circuit comprising: one or more processing devices for executing all of the above processing according to a program; and one or more program storage devices, such as a ROM, for storing a program. (b) A processing circuit comprising: one or more processing devices and one or more program storage devices for executing a portion of the above processing according to a program; and one or more dedicated hardware circuitry for executing the remaining processing. (c) A processing circuit comprising one or more dedicated hardware circuitry for executing all of the above processing. The program storage device, i.e., the computer-readable medium, includes all available media accessible by a general-purpose or special-purpose computer.

Claims

1. A control device for an internal combustion engine, the control device comprising a processing circuit, The processing circuit is configured to perform accumulation calculation and combustion rate calculation. The accumulation calculation process calculates the amount of particulate matter accumulated in the filter, which is installed in the exhaust passage of the internal combustion engine. The filter captures the particulate matter in the exhaust gas of the exhaust passage. The accumulation amount is calculated based on the discharge rate of the particulate matter from the internal combustion engine to the exhaust passage and the combustion rate of the particulate matter burned in the filter. The accumulation amount deviates in the exhaust flow direction within the filter. The combustion rate calculation process calculates the combustion rate in a manner corresponding to the degree of deviation of the accumulation amount in the exhaust flow direction.

2. The control device for an internal combustion engine according to claim 1, wherein, In the combustion rate calculation process, the combustion rate is calculated in such a way that the combustion rate under the condition of small deviation is higher than the combustion rate under the condition of large deviation.

3. The control device for an internal combustion engine according to claim 1, wherein, The processing circuit is configured to perform index value calculation processing, which calculates an index value representing the degree of deviation. In the calculation and processing of the index value, The index value is updated in such a way that the degree of deviation when the particulate matter is burning is greater than the degree of deviation when the particulate matter is not burning.

4. The control device for an internal combustion engine according to claim 3, wherein, The combustion rate calculation process includes the following steps: The base value of the combustion rate is calculated based on the value associated with the combustion rate; and The correction value is calculated based on the index value to correct the base value.

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