Engine control device

Abstract

To improve accuracy for calculating a cylinder internal intake amount.SOLUTION: In calculating a cylinder internal intake amount MC using each physical model of an air cleaner model 104, a throttle model 105, an intake pipe model 106 and an intake valve model 107, an engine control device executes a first shift correction 108 for correcting a calculation value of a throttle flow rate MT with the throttle model 105 and a second shift correction 109 for correcting a calculation value of a cylinder internal intake amount MC with the intake valve model 107.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an engine control device.

Background Art

[0002] As a calculation method for the in-cylinder intake air amount, which is the amount of intake air flowing into the combustion chamber of an engine, the method described in Patent Document 1 is known. The calculation method described in the document is a method of calculating the in-cylinder intake air amount by inputting the detected value of the intake air pressure into an intake valve model. The intake valve model is a physical model of the behavior of the intake air flowing from the intake passage through the intake valve into the combustion chamber.

[0003] Further, as a calculation method for the in-cylinder intake air amount, in addition to the above intake valve model, a method of calculating the in-cylinder intake air amount from the throttle opening using two physical models of a throttle model and an intake pipe model is also known. The throttle model is a physical model of the behavior of the intake air passing through the throttle valve. The intake pipe model is a physical model of the behavior of the intake air in the portion downstream of the throttle valve in the intake passage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The physical models as described above do not fully reproduce the actual behavior of the intake air. Therefore, in the calculation method for the in-cylinder intake air amount using the three physical models as described above, an error may occur due to the deviation between the intake air behavior of the physical model and the actual intake air behavior. Since many factors are involved in such errors, it is difficult to correct the errors.

Means for Solving the Problems

[0006] The engine control device for solving the above problems performs throttle flow rate calculation processing for calculating a throttle flow rate based on a throttle opening, a throttle upstream pressure, and a throttle downstream pressure, using a throttle model which is a physical model of the behavior of intake air passing through a throttle valve, throttle downstream pressure calculation processing for calculating a throttle downstream pressure based on the throttle flow rate and the in-cylinder intake air amount, using an intake pipe model which is a physical model of the behavior of intake air flowing through a portion downstream of the throttle valve in the intake passage, in-cylinder intake air amount calculation processing for calculating the in-cylinder intake air amount based on the throttle downstream pressure, using an intake valve model which is a physical model of the behavior of intake air flowing from the intake passage into the combustion chamber, a first shift correction for correcting a calculated value of the throttle flow rate by the throttle model based on a state quantity indicating the operating state of the engine, and a second shift correction for correcting a calculated value of the in-cylinder intake air amount by the intake valve model based on a state quantity indicating the operating state of the engine. Note that the in-cylinder intake air amount represents the amount of intake air flowing from the intake passage of the engine into the combustion chamber, the throttle opening represents the opening of the throttle valve provided in the intake passage, the throttle upstream pressure represents the pressure of the intake air before passing through the throttle valve, the throttle downstream pressure represents the pressure of the intake air after passing through the throttle valve, and the throttle flow rate represents the flow rate of the intake air passing through the throttle valve, respectively.

[0007] In the above engine control device, the in-cylinder intake air amount is calculated using each physical model of the throttle model, the intake pipe model, and the intake valve model. The calculated in-cylinder intake air amount is used for engine control. Such physical models used for calculating the in-cylinder intake air amount need to be simplified models due to limitations in the processing capacity of the engine control device and the time required for calculation completion. Therefore, a portion where the behavior of intake air in the physical model deviates from the actual behavior may occur, and an error may occur in the calculation result of the in-cylinder intake air amount.

[0008] The reduction in the calculation accuracy of the in-cylinder intake air amount due to the error of such a physical model can be suppressed by the following method. First, measure the in-cylinder intake air amount for each engine operating state with an actual engine to obtain the error of the physical model. Then, correct the calculated value of the in-cylinder intake air amount by the physical model according to the measurement result of the error. However, in order to perform such correction with high precision, actual measurement of the in-cylinder intake air amount at a huge number of operating points is required.

[0009] On the other hand, if it is not premised on use in an engine control device, since there are no restrictions on processing capacity and calculation time, it is possible to create a simulation model that reproduces the intake behavior of the engine more accurately than the physical model implemented in the engine control device. However, since the intake behavior of the entire intake system of the engine is affected by many factors and the mechanism of the influence is complex, such a simulation model cannot be easily created. In comparison, it is easy to create a simulation model limited to the intake behavior at the throttle valve or a simulation model limited to the intake behavior at the intake valve.

[0010] In the above engine control device, the error of the throttle model among the errors of the calculated result of the in-cylinder intake air amount by the physical model is corrected by the first shift correction. Also, in the above engine control device, the error of the intake valve model among the errors of the calculated result of the in-cylinder intake air amount by the physical model is corrected by the second shift correction. As described above, a simulation model limited to the intake behavior at the throttle valve and a simulation model limited to the intake behavior at the intake valve can be created relatively easily. Therefore, it is possible to easily implement the data collection in the design stage of the engine control device, which is necessary to accurately correct the errors of the throttle model and the intake valve model in the first shift correction and the second shift correction.

[0011] If the errors of the throttle model and the intake valve model can be accurately corrected, the calculation accuracy of the in-cylinder intake air amount using the physical model including them will be improved. Therefore, the above engine control device can calculate the in-cylinder intake air amount with high precision.

[0012] The above engine control device is applicable to an engine provided with a variable valve mechanism that makes the valve operating characteristics of the engine valves variable. In such a case, it is desirable to include the operating amount of the variable valve mechanism in the state quantity used for correcting the calculated value of the throttle flow rate by the first shift correction. Also, in such a case, it is desirable to include the operating amount of the variable valve mechanism in the state quantity used for correcting the calculated value of the in-cylinder intake air amount by the second shift correction.

[0013] Further, the above engine control device is applicable to an engine that performs exhaust gas recirculation into the intake air. In such a case, it is desirable to include the state quantity indicating the exhaust gas recirculation amount in the state quantity used for correcting the calculated value of the throttle flow rate by the first shift correction process. Also, in such a case, it is desirable to include the state quantity indicating the exhaust gas recirculation amount in the state quantity used for correcting the calculated value of the in-cylinder intake air amount by the second shift correction process.

[0014] The above engine control device is applicable to an engine provided with a filter device that collects particulate matter in the exhaust gas. In such a case, it is desirable to include the state quantity indicating the degree of clogging of the filter device in the state quantity used for correcting the calculated value of the in-cylinder intake air amount by the second shift correction process.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0016] (First Embodiment) Hereinafter, a first embodiment of the engine control device will be described in detail with reference to FIGS. 1 to 7. First, with reference to FIG. 1, the configuration of the engine control device of the present embodiment will be described.

[0017] <Configuration of Engine Control Device> As shown in FIG. 1, the engine 10 includes a combustion chamber 11 that performs combustion of an air-fuel mixture, an intake passage 12 that is a supply passage for intake air to the combustion chamber 11, and an exhaust passage 13 that is a discharge passage for exhaust from the combustion chamber 11. The engine 10 also includes an injector 14 that injects fuel into the intake air introduced into the combustion chamber 11 to form an air-fuel mixture. Further, the engine 10 includes an ignition device 15 that ignites the air-fuel mixture in the combustion chamber 11 by spark discharge. The combustion chamber 11 is connected to the intake passage 12 via an intake valve 19 that is an engine valve on the intake side. The combustion chamber 11 is also connected to the exhaust passage 13 via an exhaust valve 21 that is an engine valve on the exhaust side. The engine 10 is provided with an intake-side variable valve mechanism 20 that makes the valve operating characteristics of the intake valve 19 variable and an exhaust-side variable valve mechanism 22 that makes the valve operating characteristics of the exhaust valve 21 variable. The variable valve mechanisms 20 and 22 are mechanisms that make the valve timing of the intake valve 19 or the exhaust valve 21 variable, for example. In the following description, the operating amount of the intake-side variable valve mechanism 20 will be described as the intake valve timing VTI. Also, in the following description, the operating amount of the exhaust-side variable valve mechanism 22 will be described as the exhaust valve timing VTE.

[0018] An air intake passage 12 is provided with an air cleaner 16 and a throttle valve 17. The air cleaner 16 is a filter that filters the intake air taken into the air intake passage 12. The throttle valve 17 is a valve that changes the flow passage area of the intake air in accordance with the change in the opening degree. The throttle valve 17 is driven to open and close by a throttle motor 18. In the following description, the opening degree of such a throttle valve 17 is described as the throttle opening degree TA. The air intake passage 12 branches for each cylinder in an intake manifold 12A which is a branch pipe installed in a portion on the downstream side of the throttle valve 17. On the other hand, a filter device 23 for collecting particulate matter in the exhaust is installed in the exhaust passage 13.

[0019] Furthermore, the engine 10 is provided with an EGR (exhaust gas recirculation) system that recirculates a part of the exhaust into the intake air. The EGR system has an EGR passage 24 that connects the exhaust passage 13 and the air intake passage 12. Also, the EGR system has an EGR cooler 25 and an EGR valve 26. The EGR cooler 25 cools the EGR gas which is the exhaust recirculated into the intake air through the EGR passage 24. The EGR valve 26 is a valve for adjusting the EGR amount which is the flow rate of the EGR gas recirculated into the intake air.

[0020] The engine 10 is controlled by an ECM (Engine Control Module) 30. The ECM 30 includes a processing device 31 and a storage device 32. The storage device 32 stores programs and data for controlling the engine 10. The processing device 31 executes various processes for controlling the engine 10 by executing the programs read from the storage device 32. Various sensors are connected to the ECM 30. The sensors connected to the ECM 30 include an intake air temperature sensor 33, an atmospheric pressure sensor 34, a throttle opening sensor 35, a differential pressure sensor 36, a crank angle sensor 38, and an accelerator pedal sensor 40. The intake air temperature sensor 33 is a sensor that detects the intake air temperature THA, which is the temperature of the intake air taken into the intake passage 12 from the outside. The atmospheric pressure sensor 34 is a sensor that detects the atmospheric pressure PA. The throttle opening sensor 35 is a sensor that detects the throttle opening TA. The differential pressure sensor 36 is a sensor that detects the filter differential pressure ΔP, which is the pressure difference of the exhaust gas between the upstream side portion and the downstream side portion of the filter device 23 in the exhaust passage 13. The crank angle sensor 38 is a sensor that detects the crank angle CRNK, which is the rotation angle of the crankshaft 37, which is the output shaft of the engine 10. The accelerator pedal sensor 40 is a sensor that detects the depression amount ACC of the accelerator pedal 39 by the driver.

[0021] Based on the detection result of the crank angle CRNK, the ECM 30 calculates the engine speed NE. Further, based on the calculation result of the engine speed NE and the detection results such as the atmospheric pressure PA, the intake air temperature THA, and the throttle opening TA, the ECM 30 calculates the in-cylinder intake air amount MC, which is the amount of intake air introduced into the combustion chamber 11. Then, based on the calculation results of the engine speed NE and the in-cylinder intake air amount MC, the ECM 30 controls the operating state of the engine 10. The operating state of the engine 10 controlled by the ECM 30 includes the fuel injection amount QINJ of the injector 14, the ignition timing SA of the ignition device 15, the throttle opening TA, the intake valve timing VTI, and the exhaust valve timing VTE.

[0022] <Calculation process of the in-cylinder intake air amount MC> Next, with reference to FIGS. 2 to 7, the details of the calculation process of the in-cylinder intake air amount MC performed by the ECM 30 will be described.

[0023] FIG. 2 shows the processing procedure of the ECM 30 related to the calculation of the in-cylinder intake air amount MC. The ECM 30 calculates the in-cylinder intake air amount MC through the throttle upstream pressure calculation process 100, the throttle flow rate calculation process 101, the throttle downstream pressure calculation process 102, and the in-cylinder intake air amount calculation process 103. The throttle upstream pressure calculation process 100 is a process of calculating the throttle upstream pressure PAC, which is the pressure of the intake air flowing into the throttle valve 17. The throttle flow rate calculation process 101 is a process of calculating the throttle flow rate MT, which is the flow rate of the intake air passing through the throttle valve 17. The throttle downstream pressure calculation process 102 is a process of calculating the throttle downstream pressure PM, which is the pressure of the intake air in the intake manifold 12A. The in-cylinder intake air amount calculation process 103 is a process of calculating the in-cylinder intake air amount MC, which is the amount of intake air introduced from the intake passage 12 into the combustion chamber 11.

[0024] Note that the calculation of the throttle upstream pressure PAC in the throttle upstream pressure calculation process 100 is performed using the air cleaner model 104. The air cleaner model 104 is a physical model representing the behavior of the intake air passing through the air cleaner 16. Also, the calculation of the throttle flow rate MT in the throttle flow rate calculation process 101 is performed using the throttle model 105 to calculate the throttle flow rate MT. The throttle model 105 is a physical model of the behavior of the intake air passing through the throttle valve 17. Also, in the throttle downstream pressure calculation process 102, the calculation of the throttle downstream pressure PM is performed using the intake pipe model 106. The intake pipe model 106 is a physical model representing the behavior of the intake air flowing through the intake manifold 12A. Also, the calculation of the in-cylinder intake air amount MC in the in-cylinder intake air amount calculation process 103 is performed using the intake valve model 107. The intake valve model 107 is a physical model representing the behavior of the intake air flowing from the intake passage 12 into the combustion chamber 11 through the intake valve 19.

[0025] <Regarding the air cleaner model 104> First, the details of the air cleaner model 104 will be described. In the ECM30, the air cleaner model 104 is implemented as a function that takes the intake air temperature THA, atmospheric pressure PA, and throttle flow rate MT as inputs and outputs the throttle upstream pressure PAC. In the air cleaner model 104, the throttle flow rate MT is used as the flow rate of the intake air passing through the air cleaner 16. Then, based on the intake air temperature THA, atmospheric pressure PA, and throttle flow rate MT, the air cleaner model 104 calculates a value that satisfies the relationship of Equation (1) as the value of the throttle upstream pressure PAC. The "R" described in Equation (1) represents the gas constant of the intake air.

[0026]

Number

[0027] <Regarding the throttle model 105> Next, the details of the throttle model 105 will be described. In the ECM30, the throttle model 105 is implemented as a function that takes the intake air temperature THA, throttle upstream pressure PAC, throttle downstream pressure PM, and throttle opening TA as inputs and outputs the throttle flow rate MT. The throttle model 105 calculates the throttle flow rate MT as a value that satisfies the relationship shown in Equation (2). The "μ" described in Equation (2) represents the flow coefficient. Also, the "RP" described in Equation (2) represents the throttle pressure ratio, which is the ratio of the throttle downstream pressure PM to the throttle upstream pressure PAC (= PM / PAC). Furthermore, the "AT" described in Equation (2) represents the opening area of the throttle valve 17, and its value is calculated from the throttle opening TA.

[0028]

Number

[0029] The "Φ" described in Equation (2) is a value that satisfies the relationship shown in Equation (3). In the following description, this value will be referred to as the Φ value. The "κ" described in Equation (3) represents the specific heat ratio of the intake air. The Φ value is a value uniquely determined by the throttle pressure ratio RP.

[0030]

Number

[0031] Figure 3 shows the relationship between the Φ value and the throttle pressure ratio RP before and after. When the throttle pressure ratio RP before and after is less than or equal to "1 / (κ + 1)", the flow velocity of the intake air passing through the throttle valve 17 becomes equal to or higher than the speed of sound. In the following description, the region where the flow velocity of the intake air passing through the throttle valve 17 becomes equal to or higher than the speed of sound is referred to as the sonic region. The Φ value is a value representing the change rate of the throttle flow rate MT with respect to the throttle pressure ratio RP before and after. When the throttle pressure ratio RP before and after is "1", that is, when there is no pressure difference before and after the throttle valve 17, no intake air flows through the throttle valve 17. The value of the Φ value at this time becomes "0". On the other hand, in the sonic region where the throttle pressure ratio RP before and after is less than or equal to "1 / (κ + 1)", the Φ value becomes a constant value. And in the range where the value of the throttle pressure ratio RP before and after is greater than or equal to "1 / (κ + 1)" and less than or equal to "1", the Φ value is a value that increases as the value of the throttle pressure ratio RP before and after decreases.

[0032] Note that the above formula (2) can be expressed as formula (4) using the standard pressure PA0 and the standard temperature TH0. "μs" in formula (4) represents the value of the flow coefficient μ when the upstream throttle pressure PAC is the standard pressure PA0 and the intake air temperature THA is the standard temperature TH0.

[0033]

Number

[0034] Here, the value of "B" that satisfies the relationship of Equation (5) is defined as the B value. The B value is a value uniquely determined by the throttle opening TA. Also, the value of "KTHA" that satisfies the relationship of Equation (6) is defined as the temperature correction coefficient. Furthermore, the value of "KPAC" that satisfies the relationship of Equation (7) is defined as the pressure correction coefficient. At this time, the throttle flow rate MT can be expressed as the product of the B value, the temperature correction coefficient KTHA, the pressure correction coefficient KPAC, and the Φ value, as shown in Equation (8). The throttle model 105 implemented in the ECM 30 is configured to calculate the throttle flow rate MT according to Equation (8).

[0035]

Number

[0036]

Number

[0037]

Number

[0038]

Number

[0039] <Regarding the intake pipe model 106> Next, the details of the intake pipe model 106 will be described. In the ECM 30, the intake pipe model 106 is implemented as a function that takes the throttle flow rate MT, the intake air temperature THA, and the in-cylinder intake air amount MC as inputs and outputs the throttle downstream pressure PM and the throttle downstream temperature THM. The throttle downstream temperature THM represents the temperature of the intake air in the intake manifold 12A. The calculation of the throttle downstream pressure PM and the throttle downstream temperature THM in the intake pipe model 106 is performed based on the relational expressions of Equation (9) and Equation (10). The relational expressions of Equation (9) and Equation (10) are derived from the law of conservation of mass and the law of conservation of energy. "VM" described in Equation (9) and Equation (10) represents the volume of the intake manifold 12A.

[0040]

Mathematics

[0041]

Mathematics

[0042] <Regarding the intake valve model 107> Next, the details of the intake valve model 107 will be described. In the ECM 30, the intake valve model 107 is implemented as the following function. That is, it is a function that takes the downstream throttle pressure PM, the intake valve timing VTI, the intake air temperature THA, and the downstream throttle temperature THM as inputs and outputs the in-cylinder intake air amount MC. The actual intake air inflow from the intake manifold 12A to the combustion chamber 11 is intermittently performed according to the opening and closing of the intake valve 19. In the intake valve model 107, the flow rate approximated as a continuous and uniform flow is obtained as the in-cylinder intake air amount MC.

[0043] The curve L0 shown by the dashed line in FIG. 4 shows the relationship between the downstream throttle pressure PM and the in-cylinder intake air amount MC when the engine 10 is in steady operation with the engine speed NE and the operation amounts of the variable valve mechanisms 20, 22 kept constant. In the intake valve model 107, the in-cylinder intake air amount MC is calculated by approximating this curve L0 with the two straight lines L1 and L2 shown in FIG. 4. That is, in the intake valve model 107, the value of the in-cylinder intake air amount MC is calculated as a value that satisfies the relationship of Equation (11). "GL", "GH", "PMC", and "MCC" described in Equation (11) are coefficients determined based on the engine speed NE and the intake valve timing VTI, respectively.

[0044]

Mathematics

[0045] The calculated value of the in-cylinder intake air amount MC by the air cleaner model 104, throttle model 105, intake pipe model 106, and intake valve model 107 described above is used as the model value of the in-cylinder intake air amount MC. Due to factors not considered in each of the above physical models, the model value may deviate from the actual in-cylinder intake air amount MC. The engine control device of the present embodiment corrects such a deviation of the model value by the first shift correction 108 and the second shift correction 109. The first shift correction 108 is a correction for the calculated value of the throttle flow rate MT by the throttle model 105 in the throttle flow rate calculation process 101. The second shift correction 109 is a correction for the calculated value of the in-cylinder intake air amount MC by the intake valve model 107 in the in-cylinder intake air amount calculation process 103.

[0046] <Regarding the first shift correction 108> First, the details of the first shift correction 108 will be described. The inflow of intake air from the intake manifold 12A into the combustion chamber 11 is performed intermittently according to the opening and closing of the intake valve 19. As a result, intake pulsations occur in the intake passage 12 during the operation of the engine 10. And due to such intake pulsations, an intake backflow may intermittently occur in which the intake air reverses upstream through the throttle valve 17 in the intake passage 12.

[0047] On the other hand, the throttle model 105 is configured on the premise that the intake air flows uniformly from the upstream to the downstream of the intake passage 12. Therefore, in a situation where intake backflow occurs, the calculated value of the throttle flow rate MT by the throttle model 105 deviates from the actual value.

[0048] FIG. 3 shows, by a broken line, the relationship between the actual Φ value at the time of reverse flow generation and the throttle pressure ratio RP before and after the throttle. When reverse flow occurs, a deviation in the Φ value corresponding to the portion hatched in FIG. 3 occurs. Note that reverse intake flow is likely to occur when the intake flow rate is low, that is, when the throttle pressure ratio RP before and after the throttle is close to the value of "1". In the first shift correction 108, the deviation in the Φ value due to the occurrence of reverse flow is corrected. The range of the throttle pressure ratio RP before and after which reverse flow occurs and the amount of deviation in the Φ value due to reverse flow vary depending on the opening and closing timing of the intake valve 19, the valve overlap amount of the intake valve 19 and the exhaust valve 21, and the amount of exhaust recirculation into the intake air. Therefore, the ECM 30 performs correction of the Φ value based on the intake valve timing VTI, the exhaust valve timing VTE, and the EGR opening degree DEGR as the first shift correction 108. In the first shift correction 108, the intake valve timing VTI and the exhaust valve timing VTE are used as state quantities indicating the operating amounts of the variable valve mechanisms 20 and 22 that determine the opening and closing timing of the intake valve 19 and the valve overlap amount of the intake valve 19 and the exhaust valve 21. Further, the EGR opening degree DEGR is used as a state quantity indicating the amount of exhaust recirculation into the intake air.

[0049] FIG. 5 shows a control block diagram of throttle flow rate calculation process 101 to which first shift correction 108 is applied. In throttle flow rate calculation process 101, ECM 30 calculates throttle flow rate MT using throttle model 105. That is, ECM 30 calculates a B value from throttle opening TA, a temperature correction coefficient KTHA from intake air temperature THA, a pressure correction coefficient KPAC from throttle upstream pressure PAC, and a Φ value from throttle pressure ratio RP before and after, respectively. In the storage device 32 of ECM 30, the values of the B values for each value of throttle opening TA obtained in advance by experiments or the like are stored as map 110. Further, in the storage device 32, the values of the Φ values for each value of throttle pressure ratio RP before and after obtained in advance by experiments or the like are stored as map 112. ECM 30 calculates the B value using map 110 and the Φ value using map 112, respectively. Further, ECM 30 calculates the temperature correction coefficient KTHA according to the above-described formula (6) and the pressure correction coefficient KPAC according to formula (7), respectively. The throttle flow rate MT by throttle model 105 is obtained as the product of the B value, the temperature correction coefficient KTHA, the pressure correction coefficient KPAC, and the Φ value thus calculated.

[0050] On the other hand, in throttle flow rate calculation process 101, ECM 30 corrects the Φ value by first shift correction 108. When performing first shift correction 108, ECM 30 calculates three correction values SF11, SF12, and SF13.

[0051] The correction value SF11 is a correction value for correcting the change in the deviation amount of the Φ value due to the change in the intake valve timing VTI. The ECM 30 calculates the value of the correction value SF11 based on the intake valve timing VTI, the engine speed NE, and the throttle pressure ratio RP using the map 113 stored in the storage device 32. The map 113 is created as follows. First, the deviation amount of the Φ value when the intake valve timing VTI is changed at each operating point of the engine 10 defined by the engine speed NE and the throttle pressure ratio RP is obtained by simulation or the like. Then, the deviation amount is stored as the value of the correction value SF11 for each value of the engine speed NE, the throttle pressure ratio RP, and the intake valve timing VTI, and the stored data is created as the map 113.

[0052] The correction value SF12 is a correction value for correcting the change in the deviation amount of the Φ value due to the change in the exhaust valve timing VTE. The ECM 30 calculates the value of the correction value SF12 based on the exhaust valve timing VTE, the engine speed NE, and the throttle pressure ratio RP using the map 114 stored in the storage device 32. The map 114 is created as follows. First, the deviation amount of the Φ value when the exhaust valve timing VTE is changed at each operating point of the engine 10 defined by the engine speed NE and the throttle pressure ratio RP is obtained by simulation or the like. Then, the deviation amount is stored as the value of the correction value SF12 for each value of the engine speed NE, the throttle pressure ratio RP, and the exhaust valve timing VTE, and the stored data is created as the map 114.

[0053] The correction value SF13 is a correction value for correcting the change in the deviation amount of the Φ value due to the change in the EGR opening degree DEGR. The ECM 30 calculates the value of the correction value SF13 based on the EGR opening degree DEGR, the engine speed NE, and the throttle pressure ratio RP using the map 115 stored in the storage device 32. The map 115 is created as follows. First, the deviation amount of the Φ value when the EGR opening degree DEGR is changed at each operating point of the engine 10 defined by the engine speed NE and the throttle pressure ratio RP is obtained by simulation or the like. Then, the deviation amount is stored as the value of the correction value SF13 for each value of the engine speed NE, the throttle pressure ratio RP, and the EGR opening degree DEGR, and the stored data is created as the map 115.

[0054] Furthermore, in the first shift correction 108, the ECM 30 calculates the sum of the three correction values SF11, SF12, and SF13 as the value of the first shift correction value SF1. Subsequently, the ECM 30 corrects the Φ value calculated using the map 112 in the throttle model 105 with the first shift correction value SF1. Then, the ECM 30 calculates the product of the B value, the temperature correction coefficient KTHA, the pressure correction coefficient KPAC, and the corrected Φ value as the value of the throttle flow rate MT.

[0055] <Regarding the second shift correction 109> Next, the details of the second shift correction 109 will be described. As shown in FIG. 4, in the intake valve model 107, the in-cylinder intake air amount MC is calculated using an approximation of the relationship between the downstream throttle pressure PM and the in-cylinder intake air amount MC by two straight lines L1 and L2. The calculated value of the in-cylinder intake air amount MC by such an intake valve model 107 includes an approximation error. The magnitude of such an approximation error varies depending on the opening and closing timing of the intake valve 19, the valve overlap amount of the intake valve 19 and the exhaust valve 21, and the EGR amount. Also, the increase in the back pressure of the engine 10 due to clogging of the filter device 23 also affects the approximation error. Note that the ECM 30 obtains a differential pressure increase rate RPF as a state quantity indicating the degree of clogging of the filter device 23 from the detection result of the differential pressure ΔP between the front and rear of the filter by the differential pressure sensor 36. The differential pressure increase rate RPF is the ratio of the current differential pressure ΔP between the front and rear of the filter to the differential pressure ΔP between the front and rear of the filter in a state where there is no clogging at all. Then, the ECM 30 corrects the calculated value of the in-cylinder intake air amount MC of the intake valve model 107 based on the intake valve timing VTI, the exhaust valve timing VTE, the EGR opening degree DEGR, and the differential pressure increase rate RPF as the second shift correction 109. Also in such a second shift correction 109, the intake valve timing VTI and the exhaust valve timing VTE are used as the operation amounts of the variable valve mechanisms 20 and 22. Further, the EGR opening degree DEGR is used as a state quantity indicating the recirculation amount of the exhaust gas into the intake air. Furthermore, in the second shift correction 109, the differential pressure increase rate RPF is used as a state quantity indicating the degree of clogging of the filter device 23.

[0056] FIG. 6 shows a control block diagram of the in-cylinder intake air amount calculation process 103 to which the second shift correction 109 is applied. In the in-cylinder intake air amount calculation process 103, the ECM 30 calculates the values of the coefficients PMC, MCC, GL, and GH based on the engine speed NE and the intake valve timing VTI using a map 120 stored in advance in the storage device 32. Then, in process 121, the ECM 30 calculates the value of the in-cylinder intake air amount MC in the intake valve model 107 as a value that satisfies the relationship of the above-described equation (11) based on those calculation results.

[0057] On the other hand, the ECM 30 corrects the in-cylinder intake air amount MC by the second shift correction 109. When performing the second shift correction 109, the ECM 30 calculates four correction values SF21, SF22, SF23, and SF24.

[0058] The correction value SF21 is a correction value for correcting the change in the approximation error of the in-cylinder intake air amount MC due to the change in the intake valve timing VTI. The ECM 30 calculates the value of the correction value SF21 based on the intake valve timing VTI, the engine speed NE, and the throttle downstream pressure PM using the map 122 stored in the storage device 32. The map 122 is created as follows. First, the amount of approximation error of the calculated value of the in-cylinder intake air amount MC by the intake valve model 107 when the intake valve timing VTI is changed at each operating point of the engine 10 defined by the engine speed NE and the throttle downstream pressure PM is obtained by simulation or the like. Then, the map 122 is created by storing the amount of approximation error as the value of the correction value SF21 for each value of the engine speed NE, the throttle downstream pressure PM, and the intake valve timing VTI.

[0059] The correction value SF22 is a correction value for correcting the change in the approximation error amount of the in-cylinder intake air amount MC due to the change in the exhaust valve timing VTE. The ECM 30 calculates the value of the correction value SF22 based on the exhaust valve timing VTE, the engine speed NE, and the throttle downstream pressure PM using the map 123 stored in the storage device 32. The map 122 is created as follows. First, the amount of approximation error of the calculated value of the in-cylinder intake air amount MC by the intake valve model 107 when the exhaust valve timing VTE is changed at each operating point of the engine 10 defined by the engine speed NE and the throttle downstream pressure PM is obtained by simulation or the like. Then, the map 122 is created by storing the amount of approximation error as the value of the correction value SF22 for each value of the engine speed NE, the throttle downstream pressure PM, and the exhaust valve timing VTE.

[0060] The correction value SF23 is a correction value for correcting the change in the approximate error amount of the in-cylinder intake air amount MC due to the change in the EGR opening degree DEGR. The ECM 30 calculates the value of the correction value SF23 based on the EGR opening degree DEGR, the engine speed NE, and the downstream throttle pressure PM using the map 124 stored in the storage device 32. The map 124 is created as follows. First, the approximate error amount of the in-cylinder intake air amount MC when the EGR opening degree DEGR is changed at each operating point of the engine 10 defined by the engine speed NE and the downstream throttle pressure PM is obtained by simulation or the like. Then, the map 124 is created by storing the approximate error amount as the value of the correction value SF23 for each value of the engine speed NE, the downstream throttle pressure PM, and the EGR opening degree DEGR.

[0061] The correction value SF24 is a correction value for correcting the change in the approximate error amount of the in-cylinder intake air amount MC due to the change in the differential pressure increase rate RPF. The ECM 30 calculates the value of the correction value SF24 based on the differential pressure increase rate RPF, the engine speed NE, and the downstream throttle pressure PM using the map 125 stored in the storage device 32. The map 125 is created as follows. First, the approximate error amount of the in-cylinder intake air amount MC when the differential pressure increase rate RPF is changed at each operating point of the engine 10 defined by the engine speed NE and the downstream throttle pressure PM is obtained by simulation or the like. Then, the map 125 is created by storing the approximate error amount as the value of the correction value SF24 for each value of the engine speed NE, the downstream throttle pressure PM, and the differential pressure increase rate RPF.

[0062] Furthermore, in the second shift correction 109, the ECM 30 calculates the sum of the above four correction values SF21, SF22, SF23, and SF24 as the value of the second shift correction value SF2. Then, the ECM 30 calculates the value obtained by correcting the calculated value of the in-cylinder intake air amount MC by the intake valve model 107 with the second shift correction value SF2 as the final calculated value of the in-cylinder intake air amount MC in the in-cylinder intake air amount calculation process 103.

[0063] <Operation and Effect of the First Embodiment> In the engine control device of the present embodiment, the ECM 30 calculates the in-cylinder intake air amount MC using the physical models of the air cleaner model 104, the throttle model 105, the intake pipe model 106, and the intake valve model 107. The physical models used for calculating such in-cylinder intake air amount MC need to be simplified models due to the processing capacity of the ECM 30 and the limitation of the time required for calculation completion. Therefore, a part where the behavior of intake air in the physical model deviates from the actual behavior is generated, and an error may occur in the calculation result of the in-cylinder intake air amount MC.

[0064] On the other hand, if the error of the physical model for each operating state of the engine 10 is known in advance, a calibration map for correcting the error can be created. However, to create such a calibration map, it is necessary to actually measure the in-cylinder intake air amount MC of the engine 10 at a huge number of operating points, and the man-hours required for the actual measurement also become enormous. On the other hand, if the implementation in the engine control device is not premised, it is possible to create a simulation model that accurately reproduces the intake behavior of the engine 10. However, since many factors affect the intake behavior of the entire intake system of the engine 10 and the mechanism of the influence is complex, it is difficult to create such a simulation model. In comparison, it is easy to create a simulation model limited to the intake behavior at the throttle valve 17 or a simulation model limited to the intake behavior at the intake valve 19.

[0065] In the engine control device of the present embodiment, the error of the physical model is separated into the error of the throttle model 105 and the error of the intake valve model 107. Then, the error of the throttle model 105 is corrected individually by the first shift correction 108, and the error of the intake valve model 107 is corrected individually by the second shift correction 109. In the first shift correction 108, the first shift correction value SF1, which is a correction value for correcting the error of the throttle model 105, is calculated using maps 113 to 115. The data required for creating these maps 113 to 115 can be collected using a simulation model limited to the intake behavior at the throttle valve 17. On the other hand, in the second shift correction 109, the second shift correction value SF2, which is a correction value for correcting the error of the intake valve model 107, is calculated using maps 122 to 125. The data required for creating these maps 122 to 125 can be collected using a simulation model limited to the intake behavior at the intake valve 19. Therefore, the engine control device of the present embodiment has the effect of reducing the man-hours required for adaptation for correcting the error of the physical model.

[0066] When the engine 10 is mounted on a plurality of vehicle models, the range of use of the operating state of the engine 10 may vary depending on the vehicle model. It is difficult to actually measure the errors of the throttle model 105 and the intake valve model 107 in the operating state outside the range of use. Therefore, when confirming the errors of the throttle model 105 and the intake valve model 107 by actual measurement, it may be necessary to actually measure the errors for each vehicle model on which the engine 10 is mounted. In contrast, in simulation, it may be possible to reproduce an operating state that is difficult to achieve with an actual machine. Therefore, if the errors of the throttle model 105 and the intake valve model 107 can be confirmed by simulation, it will be easy to deploy the engine 10 of the same model to a plurality of vehicle models.

[0067] According to the engine control device of the present embodiment described above, the following effects can be achieved. (1) In this embodiment, the error correction of the calculated value of the in-cylinder intake air amount MC using the physical model is performed by the following two corrections. One is the first shift correction 108 for correcting the calculated value of the throttle flow rate MT by the throttle model 105. The other is the second shift correction 109 for correcting the calculated value of the in-cylinder intake air amount MC by the intake valve model 107. By correcting the error of the physical model by these two corrections, it becomes possible to calculate the in-cylinder intake air amount MC with high accuracy. Further, when the configuration is such that the error of the physical model is corrected by the two corrections of the first shift correction 108 and the second shift correction 109, the man-hours required for creating the adaptation map necessary for the correction are reduced. Therefore, the engine control device of this embodiment has the effect that it becomes easy to improve the accuracy of the calculation of the in-cylinder intake air amount MC.

[0068] (2) Since the errors of the throttle model 105 and the intake valve model 107 can be measured by simulation, it becomes easy to expand to a plurality of vehicle types of the engine 10 of the same model. (3) When the opening / closing valve timing of the intake valve 19 and the valve overlap amount of the intake valve 19 and the exhaust valve 21 change, the generation state of the intake pulsation in the intake passage 12 changes. Therefore, the error of the throttle model 105 changes according to the operation amount of the variable valve mechanisms 20, 22. In this embodiment, the first shift correction 108 is performed using the intake valve timing VTI and the exhaust valve timing VTE indicating the operation amount of the variable valve mechanisms 20, 22. Therefore, by using the intake valve timing VTI and the exhaust valve timing VTE, the error of the throttle model 105 due to the reverse flow of intake air can be accurately corrected.

[0069] (4) When the opening and closing valve timing of the intake valve 19 and the valve overlap amount of the intake valve 19 and the exhaust valve 21 change, the inertial effect and scavenging effect on the intake filling rate of the combustion chamber 11 change. Therefore, the error of the intake valve model 107 also changes according to the operation amount of the variable valve mechanisms 20 and 22. In the present embodiment, the second shift correction 109 is performed using the intake valve timing VTI and the exhaust valve timing VTE indicating the operation amount of the variable valve mechanisms 20 and 22. Therefore, by using the intake valve timing VTI and the exhaust valve timing VTE, the error of the intake valve model 107 due to the change in the intake filling efficiency caused by the operation of the variable valve mechanisms 20 and 22 can be accurately corrected.

[0070] (5) When the exhaust gas recirculation amount changes, the mass of the gas existing in the intake passage 12 changes, and the generation state of the intake pulsation changes. Therefore, the error of the throttle model 105 also changes depending on the exhaust gas recirculation amount. In the present embodiment, the first shift correction 108 is performed using the EGR opening DEGR, which is a state quantity indicating the exhaust gas recirculation amount into the intake air. Therefore, by using the EGR opening DEGR, the error of the throttle model 105 due to the intake air reverse flow can be accurately corrected.

[0071] (6) The exhaust gas recirculated into the intake air flows into the combustion chamber 11 together with the intake air. Therefore, even if the flow rate of the gas flowing into the combustion chamber 11 is the same, when the exhaust gas recirculation amount increases, the substantial intake air amount flowing into the combustion chamber 11 decreases. Therefore, the error of the intake valve model 107 also changes according to the exhaust gas recirculation amount. In the present embodiment, the second shift correction 109 is performed using the EGR opening DEGR, which is a state quantity indicating the exhaust gas recirculation amount into the intake air. Therefore, the error of the intake valve model 107 due to the exhaust gas recirculation can be accurately corrected.

[0072] (7) When the filter device 23 becomes clogged and the back pressure of the engine 10 increases, it becomes difficult for intake air to enter the combustion chamber 11. Therefore, the error of the intake valve model 107 also varies depending on the degree of clogging of the filter device 23. In the present embodiment, the second shift correction 109 is performed using the differential pressure increase rate RPF, which is a state quantity indicating the degree of clogging of the filter device 23. Therefore, the error of the intake valve model 107 caused by the increase in back pressure due to the clogging of the filter device 23 can be accurately corrected.

[0073] (Second Embodiment) Next, a second embodiment of the engine control device will be described in detail with reference to FIG. 7. In this embodiment, components common to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The difference between this embodiment and the first embodiment lies in the method of correcting the error of the intake valve model 107 by the second shift correction 109.

[0074] In the ECM 30 in the engine control device of the present embodiment, when performing the second shift correction 109, the second shift correction value SF2 is calculated as a value that satisfies the relationship of Equation (12). "PM0", "AL", "AH", "BL", "BH", and "C" described in Equation (12) are coefficients calculated based on the engine speed NE, intake valve timing VTI, exhaust valve timing VTE, EGR opening degree DEGR, and differential pressure increase rate RPF, respectively.

[0075]

Equation

[0076] FIG. 7 shows the relationship between the second shift correction value SF2 and the throttle downstream pressure PM when the coefficients PM0, AL, AH, BL, BH, and C are fixed. In this case, the second shift correction value SF2 is represented by two curves L3 and L4 with "PM0" as the boundary with respect to the throttle downstream pressure PM. The two curves L3 and L4 are curves represented by quadratic functions of the throttle downstream pressure PM.

[0077] As described above, in the intake valve model 107, the relationship between the downstream throttle pressure PM and the in-cylinder intake air amount MC is approximated by two straight lines L1 and L2 (see Fig. 4). When the relationship between the in-cylinder intake air amount MC and the downstream throttle pressure PM is approximated by a quadratic function, the error of the intake valve model 107 can be represented by two quadratic functions. Therefore, also in the correction method of the present embodiment, similar to the case of the first embodiment, the error of the intake valve model 107 can be corrected.

[0078] The above embodiment can be implemented with the following modifications. The present embodiment and the following modification examples can be implemented in combination with each other within a technically consistent range. · In the above embodiment, the error of the throttle model 105 by the first shift correction 108 was corrected by correcting the Φ value with the first shift correction value SF1. The error of the throttle model 105 by the first shift correction 108 may be corrected by other methods, such as correcting the calculated value of the throttle flow rate MT of the throttle model 105 with the first shift correction value SF1.

[0079] · In the above embodiment, the first shift correction value SF1 was calculated based on five state variables: the engine speed NE, the throttle pressure ratio RP, the intake valve timing VTI, the exhaust valve timing VTE, and the EGR opening DEGR. One or more of the above five state variables may be omitted from the state variables used in the calculation of the first shift correction value SF1. Also, state variables other than the above five state variables may be added to the state variables used in the calculation of the first shift correction value SF1. In short, among the state variables indicating the operating state of the engine 10, the state variables that have a large influence on the error of the throttle model 105 may be selected and used in the calculation of the first shift correction value SF1.

[0080] · In the above embodiment, the second shift correction value SF2 was calculated based on six state variables, namely the engine speed NE, the throttle pressure ratio RP, the intake valve timing VTI, the exhaust valve timing VTE, the EGR opening degree DEGR, and the differential pressure increase rate RPF. One or more of the above six state variables may be omitted from the state variables used in the calculation of the second shift correction value SF2. Further, state variables other than the above six state variables may be added to the state variables used in the calculation of the second shift correction value SF2. The key is to select, from among the state variables indicating the operating state of the engine 10, the state variables that have a large influence on the error of the intake valve model 107 and use them in the calculation of the second shift correction value SF2.

[0081] · In the above embodiment, the variable valve mechanisms 20 and 22 that make the opening and closing valve timing of the intake valve 19 and the exhaust valve 21 variable were adopted. However, a mechanism that makes variable valve characteristics other than the opening and closing valve timing, such as the valve lift amount, may be adopted. Even in that case, the calculation accuracy of the in-cylinder intake air amount MC can be improved by performing the first shift correction 108 and the second shift correction 109 using the state variable indicating the operation amount of the variable valve mechanism.

[0082] · In the above embodiment, the first shift correction 108 and the second shift correction 109 were performed using the EGR opening degree DEGR. Instead of the EGR opening degree DEGR, other state variables indicating the exhaust gas recirculation amount, such as the measured value or estimated value of the recirculation amount, may be used.

[0083] · In the above embodiment, the second shift correction 109 was performed using the differential pressure increase rate RPF. Instead of the differential pressure increase rate RPF, other state variables indicating the degree of clogging of the filter device 23, such as the estimated value of the amount of particulate matter deposited on the filter device 23, may be used.

[0084] · The content of each of the air cleaner model 104, the throttle model 105, the intake pipe model 106, and the intake valve model 107 may be changed as appropriate. ·When the influence of the intake pressure loss in the air cleaner 16 on the in-cylinder intake air amount MC is small, etc., the air cleaner model 104 may not be included in the physical model used for the calculation of the in-cylinder intake air amount MC.

[0085] ·In the case of an engine equipped with a supercharger, it is preferable to use the intake pressure after supercharging as the intake pressure PAC used for the calculation of the throttle flow rate MT in the throttle model 105. Also, in the throttle model 105 in that case, it is preferable to use the temperature of the intake air after supercharging instead of the intake air temperature THA.

Explanation of Symbols

[0086] 10…Engine 11…Combustion chamber 12…Intake passage 12A…Intake manifold 13…Exhaust passage 14…Injector 15…Ignition device 16…Air cleaner 17…Throttle valve 18…Throttle motor 19…Intake valve 20,22…Variable valve mechanism 21…Exhaust valve 23…Filter device 24…EGR passage 25…EGR cooler 26…EGR valve 30…ECM (Engine control module) 31…Processing device 32…Storage device 33…Intake pressure sensor 34…Intake air temperature sensor 35…Throttle opening sensor 36…Differential pressure sensor 37…Crankshaft 38…Crank angle sensor 39…Accelerator pedal 40…Accelerator pedal sensor 100…Throttle upstream pressure calculation process 101…Throttle flow rate calculation process 102…Throttle downstream pressure calculation process 103…In-cylinder intake air amount calculation process 104…Air cleaner model 105…Throttle model 106…Intake pipe model 107…Intake valve model 108…First shift correction 109…Second shift correction

Claims

1. The amount of intake air flowing from the intake passage of the engine into the combustion chamber is defined as the in-cylinder intake air amount, the opening degree of the throttle valve installed in the intake passage is defined as the throttle opening degree, the pressure of the intake air before passing through the throttle valve is defined as the throttle upstream pressure, the pressure of the intake air after passing through the throttle valve is defined as the throttle downstream pressure, and the flow rate of the intake air passing through the throttle valve is defined as the throttle flow rate. When, Using a throttle model, which is a physical model of the behavior of the intake air passing through the throttle valve, a throttle flow rate calculation process for calculating the throttle flow rate based on the throttle opening degree, the throttle upstream pressure, and the throttle downstream pressure, Using an intake pipe model, which is a physical model of the behavior of the intake air flowing through a portion of the intake passage downstream of the throttle valve, a throttle downstream pressure calculation process for calculating the throttle downstream pressure based on the throttle flow rate and the in-cylinder intake air amount, Using an intake valve model, which is a physical model of the behavior of the intake air flowing from the intake passage into the combustion chamber, an in-cylinder intake air amount calculation process for calculating the in-cylinder intake air amount based on the throttle downstream pressure, A first shift correction for correcting the calculated value of the throttle flow rate by the throttle model based on the state quantity indicating the operating state of the engine, A second shift correction for correcting the calculated value of the in-cylinder intake air amount by the intake valve model based on the state quantity indicating the operating state of the engine, are performed, The engine is provided with a variable valve mechanism that makes the valve operating characteristics of the engine valves variable, and the state quantity used for correcting the calculated value of the throttle flow rate in the first shift correction includes the operating amount of the variable valve mechanism. An engine control device.

2. The amount of intake air flowing from the intake passage of the engine into the combustion chamber is defined as the in-cylinder intake air amount, the opening degree of the throttle valve installed in the intake passage is defined as the throttle opening degree, the pressure of the intake air before passing through the throttle valve is defined as the throttle upstream pressure, the pressure of the intake air after passing through the throttle valve is defined as the throttle downstream pressure, and the flow rate of the intake air passing through the throttle valve is defined as the throttle flow rate. When, Using a throttle model, which is a physical model of the behavior of the intake air passing through the throttle valve, a throttle flow rate calculation process for calculating the throttle flow rate based on the throttle opening degree, the throttle upstream pressure, and the throttle downstream pressure, Using an intake pipe model, which is a physical model of the behavior of intake air flowing through a portion of the intake passage downstream of the throttle valve, throttle downstream pressure calculation processing for calculating the throttle downstream pressure based on the throttle flow rate and the in-cylinder intake air amount; In-cylinder intake air amount calculation processing for calculating the in-cylinder intake air amount based on the throttle downstream pressure using an intake valve model, which is a physical model of the behavior of intake air flowing from the intake passage into the combustion chamber; First shift correction for correcting the calculated value of the throttle flow rate by the throttle model based on the state quantity indicating the operating state of the engine; Second shift correction for correcting the calculated value of the in-cylinder intake air amount by the intake valve model based on the state quantity indicating the operating state of the engine; are performed, The engine is provided with a variable valve mechanism that makes the valve operating characteristics of the engine valves variable, and the state quantity used for correcting the calculated value of the in-cylinder intake air amount in the second shift correction includes the operating amount of the variable valve mechanism. An engine control device.

3. When the amount of intake air flowing from the intake passage of the engine into the combustion chamber is defined as the in-cylinder intake air amount, the opening degree of the throttle valve installed in the intake passage is defined as the throttle opening degree, the pressure of the intake air before passing through the throttle valve is defined as the throttle upstream pressure, the pressure of the intake air after passing through the throttle valve is defined as the throttle downstream pressure, and the flow rate of the intake air passing through the throttle valve is defined as the throttle flow rate, Throttle flow rate calculation processing for calculating the throttle flow rate based on the throttle opening degree, the throttle upstream pressure, and the throttle downstream pressure using a throttle model, which is a physical model of the behavior of intake air passing through the throttle valve; Throttle downstream pressure calculation processing for calculating the throttle downstream pressure based on the throttle flow rate and the in-cylinder intake air amount using an intake pipe model, which is a physical model of the behavior of intake air flowing through a portion of the intake passage downstream of the throttle valve; In-cylinder intake air amount calculation processing for calculating the in-cylinder intake air amount based on the throttle downstream pressure using an intake valve model, which is a physical model of the behavior of intake air flowing from the intake passage into the combustion chamber; First shift correction for correcting the calculated value of the throttle flow rate by the throttle model based on the state quantity indicating the operating state of the engine; Based on the state quantity indicating the operating state of the engine, perform a second shift correction for correcting the calculated value of the in-cylinder intake air quantity by the intake valve model, and The engine performs recirculation of exhaust gas into the intake air, and the state quantity used for correcting the calculated value of the throttle flow rate in the first shift correction includes a state quantity indicating the recirculation amount of the exhaust gas. An engine control device.

4. When the amount of intake air flowing from the intake passage of the engine into the combustion chamber is defined as the in-cylinder intake air quantity, the opening degree of the throttle valve installed in the intake passage is defined as the throttle opening degree, the pressure of the intake air before passing through the throttle valve is defined as the throttle upstream pressure, the pressure of the intake air after passing through the throttle valve is defined as the throttle downstream pressure, and the flow rate of the intake air passing through the throttle valve is defined as the throttle flow rate, Perform a throttle flow rate calculation process for calculating the throttle flow rate based on the throttle opening degree, the throttle upstream pressure, and the throttle downstream pressure by using a throttle model, which is a physical model of the behavior of the intake air passing through the throttle valve, Perform a throttle downstream pressure calculation process for calculating the throttle downstream pressure based on the throttle flow rate and the in-cylinder intake air quantity by using an intake pipe model, which is a physical model of the behavior of the intake air flowing through a portion downstream of the throttle valve in the intake passage, Perform an in-cylinder intake air quantity calculation process for calculating the in-cylinder intake air quantity based on the throttle downstream pressure by using an intake valve model, which is a physical model of the behavior of the intake air flowing from the intake passage into the combustion chamber, Based on the state quantity indicating the operating state of the engine, perform a first shift correction for correcting the calculated value of the throttle flow rate by the throttle model, Based on the state quantity indicating the operating state of the engine, perform a second shift correction for correcting the calculated value of the in-cylinder intake air quantity by the intake valve model, and The engine performs recirculation of exhaust gas into the intake air, and the state quantity used for correcting the calculated value of the in-cylinder intake air quantity in the second shift correction includes a state quantity indicating the recirculation amount of the exhaust gas. An engine control device.

5. The amount of intake air flowing from the intake passage of the engine into the combustion chamber is defined as the in-cylinder intake air amount, the opening degree of the throttle valve installed in the intake passage is defined as the throttle opening degree, the pressure of the intake air before passing through the throttle valve is defined as the throttle upstream pressure, the pressure of the intake air after passing through the throttle valve is defined as the throttle downstream pressure, and the flow rate of the intake air passing through the throttle valve is defined as the throttle flow rate. A throttle flow rate calculation process for calculating the throttle flow rate based on the throttle opening degree, the throttle upstream pressure, and the throttle downstream pressure using a throttle model, which is a physical model of the behavior of the intake air passing through the throttle valve. A throttle downstream pressure calculation process for calculating the throttle downstream pressure based on the throttle flow rate and the in-cylinder intake air amount using an intake pipe model, which is a physical model of the behavior of the intake air flowing through a portion of the intake passage downstream of the throttle valve. An in-cylinder intake air amount calculation process for calculating the in-cylinder intake air amount based on the throttle downstream pressure using an intake valve model, which is a physical model of the behavior of the intake air flowing from the intake passage into the combustion chamber. A first shift correction for correcting the calculated value of the throttle flow rate by the throttle model based on the state quantity indicating the operating state of the engine. A second shift correction for correcting the calculated value of the in-cylinder intake air amount by the intake valve model based on the state quantity indicating the operating state of the engine. are performed. The engine is an engine control device that includes a filter device for collecting particulate matter in the exhaust, and the state quantity used for correcting the calculated value of the in-cylinder intake air amount in the second shift correction includes a state quantity indicating the degree of clogging of the filter device.

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