Control device for internal combustion engines

Abstract

The present invention provides a control device for an internal combustion engine that accurately learns the variation in the engine's output torque from its operating conditions and controls the engine so that the output torque approaches a target torque. [Solution] A control device for an internal combustion engine that calculates an estimated torque based on angular acceleration, learns the deviation between the estimated torque and a reference value of the estimated torque as a torque error learning value, refers to torque characteristic data for the second estimated torque, calculates a second estimated torque corresponding to the current operating state for the torque characteristic data, corrects the second estimated torque using the torque error learning value to calculate a corrected second estimated torque, uses throttle torque characteristic data to calculate a target throttle opening such that the corrected second estimated torque approaches the target torque, and controls the throttle opening based on the target throttle opening.

Description

Technical Field

[0001] This application relates to a control device for an internal combustion engine.

Background Art

[0002] The control device for an internal combustion engine in Patent Document 1 controls the output torque of the internal combustion engine based on map data showing the relationship between control parameters such as intake air amount and fuel injection amount, which are operating states affecting the output torque, and the output torque. Further, in the technique of Patent Document 1, the difference between the output torque of the internal combustion engine estimated based on the current of the generator generated by the output torque of the internal combustion engine and the required torque is learned, and based on the difference, the map data is corrected so that the output torque matches the required torque.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique of Patent Document 1, the output torque of the internal combustion engine is estimated based on the current of the generator, and the variation in the output torque caused by individual differences and aging is learned. However, there is also variation in the characteristics of the generator, and since a generator that generates electricity by the output torque of the internal combustion engine is required, the operating range and device configuration that can be learned are limited.

[0005] Therefore, an object of the present application is to accurately learn the variation in the output torque of the internal combustion engine caused by individual differences and aging from the operating state of the internal combustion engine, suppress the variation in the output torque of the internal combustion engine using the learning result, and provide a control device for the internal combustion engine that controls so that the output torque approaches the target torque.

Means for Solving the Problems

[0006] The control device for an internal combustion engine according to this application is A rotation information detection unit that detects the rotational speed and angular acceleration of the crankshaft of an internal combustion engine, An estimated torque calculation unit calculates an estimated torque, which is an estimated value of the torque of the crankshaft, based on the angular acceleration. A learning value calculation unit learns the difference between the estimated torque and a preset reference value of the estimated torque as a torque error learning value. A second estimated torque calculation unit calculates the second estimated torque corresponding to the current operating state for the torque characteristic data, by referring to torque characteristic data for the second estimated torque, which has a pre-set relationship between the operating state for torque characteristic data, which includes at least one of the throttle opening, in-cylinder intake air volume, fuel injection volume, and rotational speed of the internal combustion engine, and the second estimated torque as the output torque of the internal combustion engine. A second estimated torque correction unit calculates a corrected second estimated torque by correcting the second estimated torque using the torque error learning value, A torque control unit that uses throttle torque characteristic data in which the relationship between the output torque, the rotational speed, and the throttle opening is set in advance, and calculates a target throttle opening such that the corrected second estimated torque approaches the target torque, based on the target torque of the internal combustion engine, the current rotational speed, and the corrected second estimated torque. The system includes a throttle control unit that controls the throttle opening based on the target throttle opening. [Effects of the Invention]

[0007] According to the control device for an internal combustion engine of the present invention, by comparing the estimated torque calculated based on the actually detected angular acceleration with a reference value of the estimated torque, torque variations caused by individual variations in internal combustion engines, aging (engine deterioration), etc., can be learned as torque error learning values. Then, using throttle torque characteristic data, a target throttle opening is calculated such that the corrected second estimated torque approaches the target torque, based on the target torque of the internal combustion engine, the current rotational speed, and the corrected second estimated torque corrected by the torque error learning values. This suppresses torque variations caused by individual variations in internal combustion engines, aging (engine deterioration), etc., and brings the output torque of the internal combustion engine closer to the target torque. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the control device for an internal combustion engine according to Embodiment 1. [Figure 2] This is a block diagram of the control device for an internal combustion engine according to Embodiment 1. [Figure 3] This is a hardware configuration diagram of the control device for an internal combustion engine according to Embodiment 1. [Figure 4] This is a time chart illustrating the processing of the rotation information detection unit according to Embodiment 1. [Figure 5] This diagram illustrates the relationship between each cylinder and each stroke according to Embodiment 1. [Figure 6] This figure illustrates the target torque setting data according to Embodiment 1. [Figure 7] This diagram illustrates the calculation of the maximum angular acceleration of each cylinder according to Embodiment 1. [Figure 8] This is a block diagram of the learning value calculation unit according to Embodiment 1. [Figure 9] This figure illustrates the torque characteristic data for the reference value according to Embodiment 1. [Figure 10] This figure illustrates the throttle torque characteristic data according to Embodiment 1. [Figure 11] This is a block diagram of the torque control unit according to Embodiment 1. [Figure 12] It is a block diagram for explaining an example of a target torque correction unit according to Embodiment 1. [Figure 13] It is a block diagram of a control device for an internal combustion engine according to Embodiment 2. [Figure 14] It is a block diagram of a torque control unit according to Embodiment 2. [Figure 15] It is a block diagram of a control device for an internal combustion engine according to Embodiment 3. [Figure 16] It is a block diagram of a learning value calculation unit according to Embodiment 3. [Figure 17] It is a time chart for explaining error learning according to Embodiment 3. [Figure 18] It is a time chart for explaining error learning according to Embodiment 3. [Figure 19] It is a block diagram of a control device for an internal combustion engine according to Embodiment 4. [Figure 20] It is a diagram for explaining torque characteristic data for a second estimated torque according to Embodiment 4.

Embodiments for Carrying Out the Invention

[0009] 1. Embodiment 1 The control device 50 for an internal combustion engine according to Embodiment 1 (hereinafter simply referred to as the control device 50) will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of the internal combustion engine 1 and the control device 50 according to the present embodiment, and FIG. 2 is a block diagram of the control device 50 according to the present embodiment.

[0010] 1-1. Configuration of the internal combustion engine 1 First, let's describe the configuration of the internal combustion engine 1. As shown in Figure 1, the internal combustion engine 1 is equipped with a combustion chamber 7 (hereinafter also referred to as cylinder 7) for burning a mixture of air and fuel. The internal combustion engine 1 is equipped with an intake pipe 23 that supplies air to the combustion chamber 7 and an exhaust pipe 17 that discharges exhaust gas burned in the combustion chamber 7. The internal combustion engine 1 is a gasoline engine. The internal combustion engine 1 is equipped with a throttle valve 4 that opens and closes the intake pipe 23. The throttle valve 4 is an electronically controlled throttle valve that is opened and closed by an electric motor controlled by a control device 50. The throttle valve 4 is equipped with a throttle opening sensor 19 that outputs an electrical signal corresponding to the opening degree of the throttle valve 4.

[0011] An airflow sensor 3 is provided in the intake manifold 23 upstream of the throttle valve 4, which outputs an electrical signal corresponding to the amount of intake air drawn into the intake manifold 23. The internal combustion engine 1 is equipped with an exhaust gas recirculation device 20. The exhaust gas recirculation device 20 has an EGR passage 21 that recirculates exhaust gas from the exhaust pipe 17 to the intake manifold 12, and an EGR valve 22 that opens and closes the EGR passage 21. The intake manifold 12 is the portion of the intake manifold 23 downstream of the throttle valve 4. The EGR valve 22 is an electronically controlled EGR valve that is opened and closed by an electric motor controlled by a control device 50. The exhaust pipe 17 is equipped with an air-fuel ratio sensor 18 that outputs an electrical signal corresponding to the air-fuel ratio of the exhaust gas in the exhaust pipe 17.

[0012] The intake manifold 12 is equipped with a gas pressure sensor 8 that outputs an electrical signal corresponding to the pressure inside the intake manifold 12. A fuel injector 13 is provided in the downstream portion of the intake manifold 12. The injector 13 may be configured to inject fuel directly into the cylinder 7. The internal combustion engine 1 is equipped with an atmospheric pressure sensor 33 that outputs an electrical signal corresponding to the atmospheric pressure. The internal combustion engine 1 is equipped with a water temperature sensor 34 that detects the coolant temperature.

[0013] At the top of the combustion chamber 7, there is a spark plug for igniting the air-fuel mixture and an ignition coil 16 for supplying ignition energy to the spark plug. Also at the top of the combustion chamber 7, there is an intake valve 14 for adjusting the amount of intake air drawn into the combustion chamber 7 from the intake pipe 23 and an exhaust valve 15 for adjusting the amount of exhaust gas discharged from the combustion chamber 7 to the exhaust pipe 17. The intake valve 14 is equipped with an intake variable valve timing mechanism for varying its valve opening and closing timing. The exhaust valve 15 is equipped with an exhaust variable valve timing mechanism for varying its valve opening and closing timing. The variable valve timing mechanisms 14 and 15 have electric actuators.

[0014] The internal combustion engine 1 has multiple combustion chambers 7 (four in this example). Each combustion chamber 7 is equipped with a piston 5. The piston 5 in each combustion chamber 7 is connected to the crankshaft 2 via a connecting rod 9 and a crank 32. The crankshaft 2 is rotationally driven by the reciprocating motion of the pistons 5. The combustion gas pressure generated in each combustion chamber 7 presses against the top surface of the piston 5, rotating the crankshaft 2 via the connecting rod 9 and the crank 32. The crankshaft 2 is connected to a power transmission mechanism that transmits driving force to wheels, a generator, etc. The power transmission mechanism consists of a transmission, etc.

[0015] The internal combustion engine 1 is equipped with a rotor 31 that rotates integrally with the crankshaft 2. The rotor 31 has multiple teeth at predetermined crank angles. In this embodiment, the teeth of the rotor 31 are arranged at 20-degree intervals. The teeth of the rotor 31 are provided with missing teeth portions where some teeth are missing. The internal combustion engine 1 is equipped with a crank angle sensor 11 fixed to the engine block 24 and which detects the teeth of the rotor 31.

[0016] The internal combustion engine 1 includes a crankshaft and a camshaft connected by a chain. The camshaft drives the intake valve 14 and exhaust valve 15 to open and close. The camshaft rotates once for every two rotations of the crankshaft 2. The internal combustion engine 1 includes a rotor for the cam that rotates integrally with the camshaft. The rotor for the cam has multiple teeth at multiple predetermined camshaft angles. The internal combustion engine 1 is fixed to the engine block 24 and includes a cam angle sensor 30 (see Figure 3) that detects the teeth of the rotor for the cam.

[0017] The control device 50 detects the crank angle relative to the top dead center (TDC) of each piston 5 and determines the stroke of each combustion chamber 7 based on two types of output signals from the crank angle sensor 11 and the cam angle sensor 30. The internal combustion engine 1 is a four-stroke engine consisting of an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke.

[0018] The crank angle sensor 11 and the cam angle sensor 30 output electrical signals corresponding to the change in the distance between each sensor and the teeth due to the rotation of the crankshaft 2. The output signals of each angle sensor 11 and 30 are square waves that switch on and off depending on whether the distance between the sensor and the teeth is close or far. For example, electromagnetic pickup type sensors are used for each angle sensor 11 and 30.

[0019] Furthermore, the configuration of the internal combustion engine is not limited to the configuration described using Figure 1, and various configurations of internal combustion engines may be used.

[0020] 1-2. Configuration of the control device 50 Next, the control device 50 will be described. As shown in Figure 2, the control device 50 includes processing units such as a rotation information detection unit 51, a target torque calculation unit 52, an estimated torque calculation unit 53, a learned value calculation unit 54, a torque control unit 55, and a throttle control unit 56. Each of the processing units 51 to 56 of the control device 50 is realized by a processing circuit provided by the control device 50. Specifically, as shown in Figure 3, the control device 50 includes a processing circuit such as a CPU (Central Processing Unit) or other arithmetic processing unit 90 (computer), a storage device 91 connected to the arithmetic processing unit 90 via signal lines such as a bus, an input circuit 92 for inputting external signals to the arithmetic processing unit 90, and an output circuit 93 for outputting signals from the arithmetic processing unit 90 to the outside.

[0021] The arithmetic processing unit 90 may include an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, and various signal processing circuits. Furthermore, multiple arithmetic processing units 90 of the same or different types may be provided, and each unit may perform a portion of the processing.

[0022] The memory device 91 includes volatile and non-volatile memory devices such as RAM (Random Access Memory), ROM (Read Only Memory), and EEPROM (Electrically Erasable Programmable ROM). The input circuit 92 is connected to various sensors and switches and includes an A / D converter, etc., which inputs the output signals of these sensors and switches to the arithmetic processing unit 90. The output circuit 93 is connected to electrical loads and includes a drive circuit, etc., which outputs control signals from the arithmetic processing unit 90 to these electrical loads.

[0023] The functions of each processing unit 51 to 56 of the control device 50 are realized by the arithmetic processing unit 90 executing software (programs) stored in a storage device 91 such as a ROM or EEPROM, and cooperating with other hardware of the control device 50, such as the storage device 91, input circuit 92, and output circuit 93. The setting data used by each processing unit 51 to 56, such as target torque setting data, reference torque characteristic data, throttle torque characteristic data, correction coefficient setting data, moment of inertia Icrk, and load torque τload, are stored in the storage device 91 such as a ROM or EEPROM. Furthermore, data such as the rotational speed Ne, angular velocity ωd, angular acceleration αd, maximum angular acceleration αmax, estimated torque τest, reference value τestref for estimated torque, torque error learning value Δτlrn, target throttle opening θthref0 for reference value, corrected target torque τrefcrr, correction coefficient Kτ, target torque τref, torque correction value τcom, target throttle opening θthref, and other calculated and detected values ​​calculated by each processing unit 51 to 56 are stored in a rewritable storage device 91 such as RAM.

[0024] In this embodiment, the input circuit 92 is connected to a crank angle sensor 11, a cam angle sensor 30, a water temperature sensor 34, an airflow sensor 3, a throttle opening sensor 19, a gas pressure sensor 8, an atmospheric pressure sensor 33, an air-fuel ratio sensor 18, and an accelerator position sensor 26, etc. The output circuit 93 is connected to a throttle valve 4 (electric motor), an EGR valve 22 (electric motor), an injector 13, an ignition coil 16, an intake variable valve timing mechanism 14, and an exhaust variable valve timing mechanism 15, etc. Various sensors, switches, actuators, etc., which are not shown, are connected to the control device 50. The control device 50 detects the operating state of the internal combustion engine 1, such as the throttle opening θth, the amount of intake air in the cylinder, the pressure in the intake manifold, atmospheric pressure, air-fuel ratio, and accelerator opening θaps, based on the output signals of the various sensors.

[0025] The control device 50, as a basic control, calculates the fuel injection amount, ignition timing, etc., based on the output signals of various sensors that have been input, and drives and controls the injectors 13 and ignition coils 16, etc. The control device 50 also calculates the target opening degree of the EGR valve 22 based on the output signals of various sensors that have been input, and drives and controls the electric motor of the EGR valve 22. The control device 50 also calculates the target opening and closing timing of the intake valve and the target opening and closing timing of the exhaust valve based on the output signals of various sensors that have been input, and drives and controls the intake and exhaust variable valve timing mechanisms 14 and 15 based on each target opening and closing timing.

[0026] 1-2-1. Rotation information detection unit 51 The rotation information detection unit 51 detects the rotational speed Ne and angular acceleration αd of the crankshaft of the internal combustion engine. In this embodiment, the rotation information detection unit 51 detects the crank angle θd based on the output signal of the crank angle sensor 11, and calculates the angular velocity ωd, which is the rate of change of the detected crank angle θd over time, and the angular acceleration αd, which is the rate of change of the angular velocity ωd over time. The rotation information detection unit 51 detects the rotational speed Ne of the crankshaft based on the output signal of the crank angle sensor 11. Note that the rotational speed Ne corresponds to the angular velocity ωd, but in this embodiment, it is the average speed over the stroke period.

[0027] In this embodiment, as shown in Figure 4, the rotation information detection unit 51 detects the crank angle θd based on the output signal of the crank angle sensor 11 and also detects the detection time Td at which the crank angle θd was detected. Then, based on the detected crank angle θd and detection time Td, the rotation information detection unit 51 calculates the corresponding angular interval Δθd and time interval ΔTd between the detected angles θd.

[0028] For example, the rotation information detection unit 51 detects the falling edge (or rising edge) of the output signal (square wave) of the crank angle sensor 11 and determines the crank angle θd. Using a known method, the rotation information detection unit 51 detects the crank angle θd relative to the top dead center (TDC) of the piston of the first cylinder, based on two types of output signals from the crank angle sensor 11 and the cam angle sensor 30, and also determines the stroke of each cylinder 7. Figure 5 shows the strokes of the first to fourth cylinders.

[0029] <Calculation of angular velocity ωd and angular acceleration αd> The rotation information detection unit 51 calculates the angular velocity ωd based on each crank angle θd and the detection time Td at which each crank angle θd was detected. For example, as shown in the following equation, the rotation information detection unit 51 calculates the angular velocity ωd(n) of the currently detected angle based on the angular interval Δθd(n) between the currently detected crank angle θd(n) and the previously detected crank angle θd(n-1), and the time interval ΔTd(n) between the current detection time Td(n) and the previous detection time Td(n-1). In addition, various known methods may be used to calculate the angular velocity ωd.

[0030]

number

[0031] The rotation information detection unit 51 calculates the angular acceleration αd based on the angular velocity ωd. For example, as shown in the following equation, the rotation information detection unit 51 calculates the angular acceleration αd(n) for the current detection angle based on the angular velocity ωd(n) calculated for the current detection angle, the angular velocity ωd(n-1) calculated for the previous detection angle, and the time interval ΔTd(n) for the current detection angle. In addition to this, various known methods may be used to calculate the angular acceleration αd.

[0032]

number

[0033] 1-2-2. Target Torque Calculation Unit 52 The target torque calculation unit 52 calculates the output torque τ of the internal combustion engine 1 requested by the driver as the target torque τref, based on the accelerator opening θaps detected based on the output signal of the accelerator position sensor 26, and the rotational speed Ne, etc.

[0034] For example, the target torque calculation unit 52 uses target torque setting data in which the relationship between the accelerator opening θaps, rotational speed Ne, and target torque τref is predetermined, to calculate the target torque τref corresponding to the current accelerator opening θaps and current rotational speed Ne. For example, the target torque setting data is map data in which the relationship between the accelerator opening θaps, rotational speed Ne, and target torque τref is predetermined, as shown in Figure 6. In Figure 6, the relationship between the accelerator opening θaps and target torque τref is predetermined for each of the multiple rotational speeds Ne1, Ne2, and Ne3.

[0035] 1-2-3. Estimated Torque Calculation Unit 53 The estimated torque calculation unit 53 calculates the estimated torque τest, which is an estimated value of the torque of the crankshaft, based on the angular acceleration αd.

[0036] In this embodiment, as shown in Figure 7, the estimated torque calculation unit 53 calculates the maximum value αmax of the angular acceleration αd during the combustion stroke, and calculates the estimated torque τest based on the maximum value αmax of the angular acceleration. With this configuration, by calculating the maximum value αmax of the angular acceleration during the combustion stroke, the estimated torque τest can be calculated using the maximum value αmax of the angular acceleration increased by combustion, and the maximum value of the instantaneous torque mainly increased by combustion can be calculated as the estimated torque τest.

[0037] In this embodiment, the internal combustion engine 1 is equipped with four combustion chambers 7 (cylinders 7). The estimated torque calculation unit 53 calculates the maximum values ​​of angular acceleration αmax1, αmax2, αmax3, and αmax4 for each of the four combustion chambers 7 during the combustion stroke, and calculates the estimated torque τest based on the average value αmaxave of the maximum values ​​of angular acceleration for the four combustion chambers, as shown in the following equation. The average value αmaxave is calculated every two rotations of the crankshaft.

[0038]

number

[0039] With this configuration, even if there are variations in combustion torque between cylinders, it is possible to calculate the maximum value of the average instantaneous combustion torque between cylinders.

[0040] The estimated torque calculation unit 53 calculates the estimated torque τest by multiplying the angular acceleration αd (in this example, the inter-cylinder average value of the maximum angular acceleration αmaxave) by the moment of inertia Icrk. The moment of inertia Icrk is the sum of the moments of inertia of each rotating member that rotates integrally with the crankshaft, and is preset.

[0041]

number

[0042] In this embodiment, the estimated torque calculation unit 53 calculates the estimated torque τest by subtracting the load torque τload from the product of the angular acceleration αd and the moment of inertia Icrk. The load torque τload is the various load torques applied to the crankshaft from outside the internal combustion engine, and is usually a negative value. For example, a preset value is used for the load torque τload. Alternatively, since the load torque τload does not usually fluctuate significantly during the stroke cycle, the estimated torque calculation unit 53 may use the torque obtained by multiplying the angular acceleration αd of the angle near the top dead center (TDC) of the piston by the moment of inertia Icrk as the load torque τload. The angle near top dead center (TDC) should be set to an angle within the range of 10 degrees before top dead center to 10 degrees after top dead center, for example, TDC. Near top dead center, the connecting rod and crankshaft are in a straight line, and no shaft torque is generated by the force of the in-cylinder pressure pushing the piston, so the load torque τload can be calculated. This configuration allows for the exclusion of the load torque τload applied to the crankshaft from outside the internal combustion engine, enabling the calculation of the instantaneous torque increase due to combustion and improving the accuracy of the estimated torque τest.

[0043] Furthermore, the average angular acceleration during the stroke period may be used to calculate the estimated torque τest.

[0044] 1-2-4. Learning Value Calculation Unit 54 The learning value calculation unit 54 calculates the torque error learning value Δτlrn as the deviation Δτest between the estimated torque τest and a preset reference value of the estimated torque τestref.

[0045] With this configuration, by comparing the estimated torque τest, calculated based on the actually detected angular acceleration αd, with the estimated torque reference value τestref, it is possible to learn the torque variation caused by individual variations in the internal combustion engine 1, changes over time (engine deterioration), etc., as a torque error learning value Δτlrn.

[0046] As shown in Figure 8, the learning value calculation unit 54 includes a reference value calculation unit 541 and an error learning unit 542.

[0047] <Reference value calculation unit 541> The reference value calculation unit 541 uses torque characteristic data for reference values, in which the relationship between the operating state for reference values, which includes at least one of the throttle opening θth, the amount of intake air in the cylinder, the fuel injection amount, and the rotational speed Ne, and the reference value τestref of the estimated torque is predetermined, to calculate the reference value τestref of the estimated torque corresponding to the current operating state for reference values.

[0048] Alternatively, the reference value calculation unit 541 may use torque characteristic data for reference values ​​in which the relationship between the operating state for a correction coefficient, which includes at least one of the target torque τref, the target throttle opening θthref0 for the reference value calculated based on the target torque τref, and the rotational speed Ne, and the reference value τestref of the estimated torque is predetermined.

[0049] In this embodiment, the reference value τestref of the estimated torque is the maximum value or increase in instantaneous torque increased by combustion, and therefore differs from the target torque τref, which is the average output torque during the stroke cycle. For this reason, the torque characteristic data for the reference value is set to a value corresponding to the maximum value or increase in instantaneous torque increased by combustion.

[0050] For example, let's explain the case where the throttle opening θth and rotational speed Ne are used as the operating conditions for the reference value. As shown in Figure 9, the torque characteristic data for the reference value is a map data in which the relationship between the throttle opening θth, rotational speed Ne, and the reference value τestref of the estimated torque is pre-set. The reference value calculation unit 541 refers to the torque characteristic data for the reference value and calculates the reference value τestref of the estimated torque corresponding to the current throttle opening θth and current rotational speed Ne. Here, instead of the throttle opening θth, the amount of intake air in the cylinder, the amount of fuel injected, or the target torque τref may be used. In other words, it is preferable to use rotational speed Ne and parameters correlated with output torque τ, such as the amount of intake air in the cylinder, the amount of fuel injected, or the target torque τref, as the operating conditions for the reference value.

[0051] As another example, we will explain the case where the target throttle opening θthref0 and rotational speed Ne, calculated based on the target torque τref, are used as the operating conditions for the reference value.

[0052] First, the reference value calculation unit 541 uses throttle torque characteristic data, in which the relationship between the output torque τ of the internal combustion engine, the rotational speed Ne, and the throttle opening θth is predetermined, to calculate the target torque τref as the output torque τ, and the throttle opening θth corresponding to the current rotational speed Ne as the target throttle opening θthref0 for the reference value. As shown in Figure 10, the throttle torque characteristic data is map data in which the relationship between the output torque τ, the rotational speed Ne, and the throttle opening θth is predetermined. The target torque τref is input to the output torque τ of the map data, and the current rotational speed Ne is input to the rotational speed Ne of the map data. The throttle opening θth set in the map data corresponding to the output torque τ corresponding to the target torque τref and the rotational speed Ne corresponding to the current rotational speed Ne is calculated, and the calculated throttle opening θth is calculated as the target throttle opening θthref0 for the reference value.

[0053] In this case, in the torque characteristic data for the reference value shown in Figure 9, the throttle opening θth is changed to the target throttle opening θthref0 for the reference value. The reference value calculation unit 541 refers to the torque characteristic data for the reference value and calculates the reference value τestref of the estimated torque corresponding to the target throttle opening θthref0 for the reference value and the current rotational speed Ne. Here, instead of the target throttle opening θthref0 for the reference value, the target value of the in-cylinder intake air volume may be used.

[0054] Furthermore, various internal combustion engine operating conditions that correlate with output torque τ may be used as reference values, such as EGR rate, ignition timing, intake valve opening / closing timing, and exhaust valve opening / closing timing. The torque characteristic data for the reference values ​​may be a combination of multiple map data, or it may be calculated from a mathematical model using a neural network.

[0055] <Error Learning Unit 542> The error learning unit 542 updates the torque error learning value Δτlrn based on the deviation Δτest between the estimated torque τest and the reference value τestref of the estimated torque.

[0056] The error learning unit 542 updates the torque error learning value Δτlrn by performing statistical processing on the deviation Δτest. For example, a low-pass filter is performed as part of the statistical processing. The error learning unit 542 updates the torque error learning value Δτlrn using the following equation. Here, (j) represents the calculated value of the current update cycle, (j-1) represents the calculated value of the previous update cycle, and Kflt is a filter gain set to a value less than 1. In this embodiment, the update cycle is set to the period of two rotations of the crankshaft.

[0057]

number

[0058] Furthermore, a torque error learning value Δτlrn may be provided and updated for each of the multiple regions set according to the operating conditions, which include at least one of the following: throttle opening θth, in-cylinder intake air volume, fuel injection volume, and rotational speed Ne. In other words, multiple torque error learning values ​​Δτlrn are provided and updated corresponding to multiple regions.

[0059] Furthermore, as an alternative example of calculating multiple torque error learning values ​​Δτlrn, long-term and short-term statistical processing may be performed to calculate the long-term and short-term torque error learning values. For example, equation (5) is used for both the calculation of the long-term torque error learning value and the calculation of the short-term torque error learning value, and the filter gain Kflt for the long-term torque error learning value is set to a smaller value than the filter gain Kflt for the short-term torque error learning value.

[0060] 1-2-5. Torque control unit 55 The torque control unit 55 uses throttle torque characteristic data, which has a pre-set relationship between the output torque τ of the internal combustion engine, the rotational speed Ne, and the throttle opening θth, to calculate a target throttle opening θthref such that the output torque τ of the internal combustion engine, taking into account the torque error learning value Δτlrn, approaches the target torque τref, based on the target torque τref of the internal combustion engine, the current rotational speed Ne, and the torque error learning value Δτlrn.

[0061] In this embodiment, as shown in Figure 11, the torque control unit 55 includes a target torque correction unit 551 and a target throttle opening calculation unit 552. The target torque correction unit 551 corrects the target torque τref based on the torque error learning value Δτlrn and calculates the corrected target torque τrefcrr. The target throttle opening calculation unit 552 then refers to throttle torque characteristic data in which the relationship between the output torque τ of the internal combustion engine, the rotational speed Ne, and the throttle opening θth is set in advance, and calculates the corrected target torque τrefcrr as the output torque τ, and the throttle opening θth corresponding to the current rotational speed Ne as the target throttle opening θthref.

[0062] With this configuration, the target torque τref is corrected using the torque error learning value Δτlrn, and the corrected target torque τrefcrr is calculated. This compensates for output torque errors caused by deviations in throttle torque characteristic data resulting from individual variations in internal combustion engines 1, aging (engine deterioration), etc., and allows the output torque τ of the internal combustion engine to approach the target torque τref with high accuracy.

[0063] <Target Torque Correction Unit 551> The target torque correction unit 551 corrects the target torque τref based on the torque error learning value Δτlrn and calculates the corrected target torque τrefcrr. For example, the target torque correction unit 551 calculates the corrected target torque τrefcrr using the following equation.

number

[0064] Alternatively, the target torque correction unit 551 may calculate a correction coefficient Kτ based on operating conditions for a correction coefficient that include at least one of the throttle opening θth, in-cylinder intake air volume, fuel injection volume, and rotational speed Ne, and calculate the corrected target torque τrefcrr by adding the product of the torque error learning value Δτlrn and the correction coefficient Kτ to the target torque τref, as shown in the following equation.

number

[0065] Since the degree of influence of the torque error learning value Δτlrn on the estimated torque changes depending on the operating conditions, the correction accuracy can be improved by multiplying the torque error learning value Δτlrn by the correction coefficient Kτ. Furthermore, since the proportionality constant of the average output torque during the stroke period to the maximum value or increase in instantaneous torque increased by combustion changes depending on the operating conditions, the correction coefficient Kτ can be calculated based on the operating conditions for the correction coefficient, and the correction accuracy can be improved by multiplying the torque error learning value Δτlrn by the correction coefficient Kτ.

[0066] For example, the target torque correction unit 551 refers to correction coefficient setting data, in which the relationship between the operating state for the correction coefficient and the correction coefficient Kτ is set in advance, and calculates the correction coefficient Kτ corresponding to the current operating state for the correction coefficient. For example, the correction coefficient setting data is configured in the same way as torque characteristic data for reference values, and map data may be used.

[0067] Alternatively, the target torque correction unit 551 may calculate a torque correction value τcom by feedback control such as PI (Proportional-Integral) control so that the torque error learning value Δτlrn approaches the target learning value Δτlrnref (usually 0) over time, correct the target torque τref with the torque correction value τcom, and calculate the corrected target torque τrefcrr.

[0068] Figure 12 shows an example of using PI control in the target torque correction unit 551. In the figure, s is the Laplace operator, and 1 / s represents the integral. The target torque correction unit 551 calculates the deviation err between the torque error learning value Δτlrn and the target learning value Δτlrnref (0 in this example), and performs PI control on the deviation err to calculate the torque correction value τcom. Then, the target torque correction unit 551 subtracts the torque correction value τcom from the target torque τref to calculate the corrected target torque τrefcrr. The calculations in Figure 12 can be expressed by equations (8) and (9). Here, (j) is the calculated value for the current update cycle as described above, and (j-1) is the calculated value for the previous update cycle. Also, Kp and Ki are the proportional gain and integral gain of the PI controller, respectively.

number

number

[0069] With this configuration, the torque correction value τcom, which corrects the target torque τref, is updated with each update cycle using feedback control such as PI control. As a result, the torque error learning value Δτlrn can be converged to the target learning value Δτlrnref (0 in this example) over time. This makes it possible to obtain the output torque τ of the internal combustion engine 1 with suppressed variation.

[0070] <Target opening calculation unit 552> The target throttle opening calculation unit 552 refers to throttle torque characteristic data in which the relationship between the output torque τ of the internal combustion engine, the rotational speed Ne, and the throttle opening θth is set in advance, and calculates the corrected target torque τrefcrr as the output torque τ, and the throttle opening θth corresponding to the current rotational speed Ne as the target throttle opening θthref.

[0071] The throttle torque characteristic data used here is the same as the throttle torque characteristic data used in the reference value calculation unit 541, and the same data may be used. As shown in Figure 10, the throttle torque characteristic data is map data in which the relationship between output torque τ, rotational speed Ne, and throttle opening θth is set in advance. The corrected target torque τrefcrr is input to the output torque τ of the map data, and the current rotational speed Ne is input to the rotational speed Ne of the map data. The throttle opening θth set in the map data is calculated in correspondence with the output torque τ corresponding to the corrected target torque τrefcrr and the rotational speed Ne corresponding to the current rotational speed Ne, and the calculated throttle opening θth is calculated as the target throttle opening θthref.

[0072] 1-2-6. Throttle control unit 56 The throttle control unit 56 controls the throttle opening θth based on the target throttle opening θthref. In this embodiment, the throttle control unit 56 drives the electric motor of the throttle valve 4 so that the throttle opening θth detected based on the output signal of the throttle opening sensor 19 approaches the target throttle opening θthref.

[0073] 2. Embodiment 2 The control device 50 according to Embodiment 2 will be described with reference to the drawings. Figure 13 is a functional block diagram showing the operation of the control device 50 of this embodiment. The same components as in Embodiment 1 will not be described. The basic configuration of the control device 50 according to this embodiment is the same as in Embodiment 1. In this embodiment, some of the processing of the torque control unit 55 differs from that of Embodiment 1.

[0074] In this embodiment, as shown in Figure 14, the torque control unit 55 includes a target opening degree calculation unit 552 and a target opening degree correction unit 553.

[0075] In this embodiment, the target throttle opening calculation unit 552 refers to throttle torque characteristic data in which the relationship between the output torque τ of the internal combustion engine, the rotational speed Ne, and the throttle opening θth is set in advance, and calculates the target torque τref as the output torque τ, and the throttle opening θth corresponding to the current rotational speed Ne as the target throttle opening θthrefbf before correction.

[0076] The throttle torque characteristic data used here is the same as the throttle torque characteristic data used in the reference value calculation unit 541 of Embodiment 1, and the same data may be used. As shown in Figure 10, the throttle torque characteristic data is map data in which the relationship between output torque τ, rotational speed Ne, and throttle opening θth is set in advance. The target torque τref is input to the output torque τ of the map data, and the current rotational speed Ne is input to the rotational speed Ne of the map data. The throttle opening θth set in the map data is calculated in correspondence with the output torque τ corresponding to the target torque τref and the rotational speed Ne corresponding to the current rotational speed Ne, and the calculated throttle opening θth is calculated as the target throttle opening θthrefbf before correction.

[0077] The target throttle opening correction unit 553 corrects the target throttle opening θthref before correction based on the torque error learning value Δτlrn and calculates the target throttle opening θthref.

[0078] With this configuration, the target throttle opening θthref before correction, which corresponds to the target torque τref, is corrected using the torque error learning value Δτlrn, and the target throttle opening θthref is calculated. This compensates for the output torque error caused by deviations in throttle torque characteristic data due to individual variations in the internal combustion engine 1, aging, etc., and allows the output torque τ of the internal combustion engine to approach the target torque τref with high accuracy.

[0079] For example, the target throttle opening correction unit 553 calculates a conversion coefficient Kcnv based on operating conditions for a conversion coefficient that include at least one of the following: throttle opening θth, in-cylinder intake air volume, fuel injection volume, and rotational speed Ne. As shown in the following equation, the unit calculates the target throttle opening θthref by adding the product of the torque error learning value Δτlrn and the conversion coefficient Kcnv to the target throttle opening θthrefbf before correction. The conversion coefficient Kcnv is a conversion coefficient that converts the torque deviation into the throttle opening deviation that causes the torque deviation.

number

[0080] For example, the target opening correction unit 553 refers to conversion coefficient setting data in which the relationship between the operating state for the conversion coefficient and the conversion coefficient Kcnv is set in advance, and calculates the conversion coefficient Kcnv corresponding to the current operating state for the conversion coefficient. For example, the conversion coefficient setting data is configured in the same way as torque characteristic data for reference values, and map data is used, for example.

[0081] Alternatively, the target throttle opening correction unit 553 may calculate a throttle opening correction value θthcom by feedback control such as PI (Proportional-Integral) control so that the torque error learning value Δτlrn approaches the target learning value Δτlrnref (usually 0) over time, and then correct the target throttle opening θthrefbf before correction using the throttle opening correction value θthcom to calculate the target throttle opening θthref.

[0082] For example, as shown in equations (11) and (12), the target throttle opening correction unit 553 calculates the deviation err between the torque error learning value Δτlrn and the target learning value Δτlrnref (0 in this example), and performs PI control on the deviation err to calculate the throttle opening correction value θthcom. Then, the target throttle opening correction unit 553 subtracts the throttle opening correction value θthcom from the target throttle opening θthrefbf before correction to calculate the target throttle opening θthref. Here, (j) represents the calculated value for the current update cycle as described above, and (j-1) represents the calculated value for the previous update cycle. Also, Kp2 and Ki2 are the proportional gain and integral gain of the PI controller, respectively.

number

number

[0083] With this configuration, the throttle opening correction value θthcom, which corrects the target throttle opening θthrefbf before correction, is updated with feedback control such as PI control at each update cycle. As a result, the torque error learning value Δτlrn can be converged to the target learning value Δτlrnref (0 in this example) over time. This makes it possible to obtain the output torque τ of the internal combustion engine 1 with suppressed variation.

[0084] 3. Embodiment 3 The control device 50 according to Embodiment 3 will be described with reference to the drawings. Figure 15 is a functional block diagram showing the operation of the control device 50 of this embodiment. The same components as those in Embodiment 1 or 2 described above will not be explained. The basic configuration of the control device 50 according to this embodiment is the same as that of Embodiment 1 or 2. In this embodiment, some of the processing of the learning value calculation unit 54 differs from that of Embodiment 1 or 2.

[0085] In this embodiment, as shown in Figure 16, the learning value calculation unit 54 includes a learning condition determination unit 543 in addition to the reference value calculation unit 541 and the error learning unit 542.

[0086] The learning condition determination unit 543 determines whether the learning conditions are met based on the operating state for learning determination, which includes at least one of the following: throttle opening θth, in-cylinder intake air volume, fuel injection volume, and rotational speed Ne. If the learning conditions are met, the error learning unit 542 updates the torque error learning value Δτlrn based on the deviation Δτest.

[0087] The learning condition determination unit 543 may use one or more of the following as conditions for determining whether or not the learning conditions are met: environmental conditions such as intake air temperature, coolant temperature, and atmospheric pressure, and the operating state of the power transmission mechanism such as the gear and clutch to which the crankshaft of the internal combustion engine 1 is connected.

[0088] This configuration allows for improved learning accuracy by performing learning only when pre-set learning conditions are met.

[0089] In this embodiment, as shown in Figures 17 and 18, the learning condition determination unit 543 determines that the learning condition is met when the rotation speed Ne passes a preset determination rotation speed Thne while the rotation speed Ne is increasing.

[0090] When the rotational speed Ne is accelerating or decelerating, the torque of the internal combustion engine is in a transient state of increasing and decreasing, and performing learning in this transient state is likely to lead to a decrease in learning accuracy. When the rotational speed Ne is continuously increasing, the torque fluctuations are small and stable, so learning accuracy can be improved. In particular, in the case of two-wheeled vehicles, the output of the internal combustion engine is small and the inertia is low compared to four-wheeled vehicles, so learning accuracy is easily reduced by fluctuating factors, but the above configuration can suppress the decrease in learning accuracy.

[0091] For example, the learning condition determination unit 543 determines that the learning condition is met when the rotation speed Ne has been continuously increasing during the determination period Tjd, and the rotation speed Ne has passed the determined rotation speed Thne.

[0092] By setting a judgment period Tjd, it becomes possible to more accurately determine when the torque is stable with minimal fluctuations, thereby improving learning accuracy.

[0093] Furthermore, the learning condition determination unit 543 may determine that the learning condition has been met when, during the determination period Tjd, the rotation speed Ne has continuously increased within a preset increase rate range, and the rotation speed Ne has passed the determined rotation speed Then.

[0094] By setting a range for the rate of increase of the rotational speed Ne, it is possible to more accurately determine a stable state with minimal torque fluctuations, thereby improving learning accuracy.

[0095] Furthermore, the learning condition determination unit 543 may, in addition to the condition for rotational speed Ne, also include the condition that the cooling water temperature is above a preset temperature as a condition for determining that the learning conditions have been met.

[0096] This configuration allows the system to determine if the internal combustion engine 1 has not reached an appropriate temperature, such as immediately after a cold start, based on the coolant temperature. If the coolant temperature falls below a preset temperature, the system determines that the torque output characteristics differ from the standard operating state, and therefore the learning condition is not met, and learning is not performed. In this way, by determining whether the learning condition is met based on environmental conditions such as coolant temperature, if the operating state at the time of learning differs from the standard operating state, the learning condition is not met, and learning is not performed. This limits the learning condition to the operating state, thereby suppressing variations in the learning values ​​for each learning session.

[0097] The behavior during learning will be explained using Figures 17 and 18. First, Figure 17 will be explained. In Figure 17, the internal combustion engine is in a state with no individual variation or age-related changes, the estimated torque τest and the reference value of the estimated torque τestref are in agreement, and the deviation Δτest is close to zero. The throttle opening θth increases, the torque increases, and the rotational speed Ne increases continuously. During the increase in rotational speed Ne, at time t01, the rotational speed Ne passes the judgment rotational speed Thne, and the learning condition is met. The deviation Δτest when the learning condition is met is learned as the torque error learning value Δτlrn.

[0098] Next, Figure 18 will be explained. In Figure 18, the internal combustion engine exhibits individual variations and age-related changes, and the estimated torque τest exceeds the baseline value τestref, while the deviation Δτest is less than zero. As the throttle opening θth increases, the torque increases, and the rotational speed Ne increases continuously. During the increase in rotational speed Ne, at time t01, the rotational speed Ne passes the judgment rotational speed Thne, and the learning condition is met. The deviation Δτest when the learning condition is met is learned as the torque error learning value Δτlrn.

[0099] Alternatively, the average of multiple deviations Δτest when the learning conditions are met multiple times may be learned as the torque error learning value Δτlrn.

[0100] Furthermore, before the internal combustion engine 1 stops and the processing operation ends, the control device 50 stores one or more torque error learning values ​​Δτlrn in a non-volatile memory device such as an EEPROM. Then, when the control device 50 restarts, it reads the torque error learning values ​​Δτlrn stored in the memory device. As a result, even after restarting, the control device 50 can calculate the target throttle opening θthref using the torque error learning values ​​Δτlrn learned up to the previous restart. Therefore, it can compensate for output torque errors caused by deviations in throttle torque characteristic data due to individual variations in the internal combustion engine 1, aging, etc., and accurately bring the output torque τ of the internal combustion engine closer to the target torque τref.

[0101] 4. Embodiment 4 The control device 50 according to Embodiment 4 will be described with reference to the drawings. The same components as those in Embodiments 1, 2, or 3 described above will not be described.

[0102] In this embodiment, as shown in Figure 19, the control device 50 includes a second estimated torque calculation unit 57 and a second estimated torque correction unit 58, in addition to processing units such as a rotation information detection unit 51, a target torque calculation unit 52, an estimated torque calculation unit 53, a learned value calculation unit 54, a torque control unit 55, and a throttle control unit 56. Furthermore, in this embodiment, some of the processing of the torque control unit 55 differs from that of embodiments 1, 2, or 3. Each of the processing units 51 to 58 of the control device 50 is implemented by a processing circuit provided in the control device 50, similar to embodiment 1.

[0103] The second estimated torque calculation unit 57 uses torque characteristic data for the second estimated torque, in which the relationship between the operating state for torque characteristic data, which includes at least one of the throttle opening θth, the amount of intake air in the cylinder, the fuel injection amount, and the rotational speed Ne, and the second estimated torque τest2 as the output torque τ of the internal combustion engine is predetermined, to calculate the second estimated torque τest2 corresponding to the current operating state for torque characteristic data. Here, the second estimated torque τest2 is the torque output from the crankshaft to the outside of the internal combustion engine, is the average output torque during the stroke cycle, and corresponds to the target torque τref. Therefore, the torque characteristic data for the second estimated torque is different from the torque characteristic data for the reference value used in the learning value calculation unit 54.

[0104] For example, let's explain the case where the throttle opening θth and rotational speed Ne are used as operating conditions for torque characteristic data. As shown in Figure 20, the torque characteristic data for the second estimated torque is a map data in which the relationship between the throttle opening θth, rotational speed Ne, and the second estimated torque τest2 is pre-set. The second estimated torque calculation unit 57 refers to the torque characteristic data for the second estimated torque and calculates the second estimated torque τest2 corresponding to the current throttle opening θth and rotational speed Ne. Here, instead of the throttle opening θth, the amount of intake air in the cylinder, the amount of fuel injected, or the target torque τref may be used. That is, it is preferable to use rotational speed Ne and parameters correlated with output torque τ, such as the amount of intake air in the cylinder, the amount of fuel injected, or the target torque τref, as operating conditions for the reference value.

[0105] Furthermore, various internal combustion engine operating conditions that correlate with output torque τ may be used as operating conditions for torque characteristic data, such as EGR rate, ignition timing, intake valve opening / closing timing, and exhaust valve opening / closing timing. The torque characteristic data for the second estimated torque may be a combination of multiple map data, or it may be calculated from a mathematical model using a neural network.

[0106] The second estimated torque correction unit 58 corrects the second estimated torque τest2 using the torque error learning value Δτlrn to calculate the corrected second estimated torque τest2crr. For example, the second estimated torque correction unit 58 calculates the corrected second estimated torque τest2crr using the following equation.

number

[0107] With this configuration, the torque error learning value Δτlrn, which is learned from the torque variations caused by individual variations in the internal combustion engine 1 and age-related changes (engine deterioration), corrects the second estimated torque τest2, which is calculated by referring to pre-set torque characteristic data for the second estimated torque, and calculates the corrected second estimated torque τest2crr. This makes it possible to calculate an accurate torque estimate that reflects the torque variations caused by individual variations in the internal combustion engine 1 and age-related changes (engine deterioration).

[0108] Alternatively, the second estimated torque correction unit 58 may calculate a correction coefficient Kτest based on operating conditions for a correction coefficient that include at least one of the throttle opening θth, in-cylinder intake air volume, fuel injection volume, and rotational speed Ne, and then calculate the corrected second estimated torque τest2crr by adding the product of the torque error learning value Δτlrn and the correction coefficient Kτest to the second estimated torque τest2, as shown in the following equation.

number

[0109] With this configuration, the degree of influence of the torque error learning value Δτlrn on the estimated torque changes depending on the operating conditions. Therefore, the correction accuracy can be improved by multiplying the torque error learning value Δτlrn by the correction coefficient Kτest. Furthermore, the proportionality constant of the average output torque τ during the stroke period with respect to the maximum value or increase in instantaneous torque increased by combustion changes depending on the operating conditions. Therefore, the correction coefficient Kτest can be calculated based on the operating conditions for the correction coefficient, and the correction accuracy can be improved by multiplying the torque error learning value Δτlrn by the correction coefficient Kτest.

[0110] The second estimated torque correction unit 58 refers to correction coefficient setting data, which has a pre-set relationship between the operating state for the correction coefficient and the correction coefficient Kτest, and calculates the correction coefficient Kτest corresponding to the current operating state for the correction coefficient. The correction coefficient setting data is configured in the same way as torque characteristic data for reference values, and for example, map data is used.

[0111] The torque control unit 55 uses throttle torque characteristic data, which has a pre-set relationship between the output torque τ of the internal combustion engine, the rotational speed Ne, and the throttle opening θth, to calculate a target throttle opening θthref such that the corrected second estimated torque τest2crr approaches the target torque τref, based on the target torque τref of the internal combustion engine, the current rotational speed Ne, and the corrected second estimated torque τest2crr.

[0112] With this configuration, by calculating a target throttle opening θthref such that the corrected second estimated torque τest2crr, which is a highly accurate torque estimate that reflects individual variations in the internal combustion engine 1 and torque variations caused by aging, approaches the target torque τref, the output torque error caused by deviations in throttle torque characteristic data due to individual variations in the internal combustion engine 1 and aging can be compensated for, and the output torque τ of the internal combustion engine can be brought closer to the target torque τref with high accuracy. As shown in Figure 19, the torque control unit 55 includes a target torque correction unit 551 and a target throttle opening calculation unit 552.

[0113] The target torque correction unit 551 calculates the corrected target torque τrefcrr using feedback control such as PI (Proportional-Integral) control so that the corrected second estimated torque τest2crr approaches the target torque τref over time.

[0114] As shown in equations (15) and (16), the target torque correction unit 551 calculates the torque deviation τerr between the corrected second estimated torque τest2crr and the target torque τref, and performs PI control on the torque deviation τerr to calculate the torque correction value τcom2. Then, the target torque correction unit 551 subtracts the torque correction value τcom2 from the target torque τref to calculate the corrected target torque τrefcrr. Here, (j) represents the calculated value for the current update cycle as described above, and (j-1) represents the calculated value for the previous update cycle. Also, Kp3 and Ki3 are the proportional gain and integral gain of the PI controller, respectively.

number

number

[0115] With this configuration, the torque correction value τcom, which corrects the target torque τref, is updated with each update cycle using feedback control such as PI control. As a result, the corrected second estimated torque τest2crr can be converged to the target torque τref over time. This makes it possible to obtain the output torque τ of the internal combustion engine 1 with suppressed variation.

[0116] The target opening degree calculation unit 552 refers to throttle torque characteristic data in which the relationship between the output torque τ of the internal combustion engine, the rotational speed Ne, and the throttle opening degree θth is predetermined, and calculates the corrected target torque τrefcrr as the output torque τ, and the throttle opening degree θth corresponding to the current rotational speed Ne as the target throttle opening degree θthref. The configuration of the target opening degree calculation unit 552 is the same as in Embodiment 1, so a description is omitted.

[0117] In each of the embodiments described above, the control device 50 is shown to calculate the target throttle opening θthref using the torque error learning value Δτlrn, the corrected second estimated torque τest2crr, etc., so that the output torque τ of the internal combustion engine 1 approaches the target torque τref. As another example, the control device 50 may transmit the torque error learning value Δτlrn, the corrected second estimated torque τest2crr, etc., to an external control device such as a vehicle control device or a motor control device, and reflect it in the torque control of the external control device.

[0118] In each of the embodiments described above, the case in which a four-cylinder internal combustion engine is used was explained as an example. However, an internal combustion engine with any number of cylinders (for example, 1 cylinder, 2 cylinders, 3 cylinders, or 6 cylinders) may be used.

[0119] While this application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are envisioned within the scope of the art disclosed herein. For example, these include modifying, adding, or omitting at least one component, or even extracting at least one component and combining it with a component from another embodiment. [Explanation of Symbols]

[0120] 1: Internal combustion engine, 2: Crankshaft, 7: Combustion chamber, 50: Control device for internal combustion engine, 51: Rotation information detection unit, 52: Target torque calculation unit, 53: Estimated torque calculation unit, 54: Learning value calculation unit, 55: Torque control unit, 56: Throttle control unit, 57: Second estimated torque calculation unit, 58: Second estimated torque correction unit, Ne: Rotational speed, Thne: Judgment rotational speed, Tjd: Judgment period, err: Deviation, Δτlrn: Torque error learning value, Δτlrnref: Target learning value, αd: Angular acceleration, αmax: Maximum value of angular acceleration, αmaxave θth: Average of maximum values, θth: Throttle opening, θthcom: Throttle opening correction value, θthref: Target throttle opening, θthref0: Target throttle opening for reference value, θthrefbf: Target throttle opening before correction, τ: Output torque, τcom: Torque correction value, τcom2: Torque correction value, τest: Estimated torque, τest2: Second estimated torque, τest2crr: Second estimated torque after correction, τestref: Reference value of estimated torque, τref: Target torque, τrefcrr: Target torque after correction

Claims

1. A rotation information detection unit that detects the rotational speed and angular acceleration of the crankshaft of an internal combustion engine, An estimated torque calculation unit calculates an estimated torque, which is an estimated value of the torque of the crankshaft, based on the angular acceleration. A learning value calculation unit that learns the deviation between the estimated torque and a preset reference value of the estimated torque as a torque error learning value; and a second estimated torque calculation unit that calculates the second estimated torque corresponding to the current operating state for the torque characteristic data, by referring to torque characteristic data for the second estimated torque, which is preset in relation to the relationship between the operating state for torque characteristic data, which includes at least one of the throttle opening, in-cylinder intake air volume, fuel injection volume, and rotational speed of the internal combustion engine, and the second estimated torque as the output torque of the internal combustion engine. A second estimated torque correction unit calculates a corrected second estimated torque by correcting the second estimated torque using the torque error learning value, A torque control unit that uses throttle torque characteristic data in which the relationship between the output torque, the rotational speed, and the throttle opening is set in advance, and calculates a target throttle opening such that the corrected second estimated torque approaches the target torque, based on the target torque of the internal combustion engine, the current rotational speed, and the corrected second estimated torque. A control device for an internal combustion engine, comprising: a throttle control unit that controls the throttle opening based on the target throttle opening; and

2. The torque control unit calculates a torque correction value by feedback control so that the corrected second estimated torque approaches the target torque, corrects the target torque using the torque correction value, and calculates the corrected target torque. A control device for an internal combustion engine according to claim 1, which refers to the throttle torque characteristic data and calculates the corrected target torque as the output torque and the throttle opening corresponding to the current rotational speed as the target throttle opening.

3. The control device for an internal combustion engine according to claim 1 or 2, wherein the estimated torque calculation unit calculates the maximum value of the angular acceleration during the combustion stroke and calculates the estimated torque based on the maximum value.

4. The aforementioned internal combustion engine is equipped with multiple combustion chambers, The control device for an internal combustion engine according to claim 1 or 2, wherein the estimated torque calculation unit calculates the maximum value of the angular acceleration during the combustion stroke for each of the plurality of combustion chambers, and calculates the estimated torque based on the average value of the maximum values ​​of the plurality of combustion chambers.

5. The control device for an internal combustion engine according to claim 1 or 2, wherein the learning value calculation unit calculates the reference value of the estimated torque corresponding to the current operating state for the reference value, using reference value torque characteristic data in which the relationship between the operating state for the reference value, which includes the target torque, the target throttle opening for the reference value calculated based on the target torque, the throttle opening, the amount of intake air in the cylinder, the amount of fuel injection, and the rotational speed, is predetermined.

6. The control device for an internal combustion engine according to claim 1 or 2, wherein the learning value calculation unit stores the torque error learning value in a storage device, and reads the torque error learning value stored in the storage device when the control device for the internal combustion engine is restarted after being stopped.

7. The control device for an internal combustion engine according to claim 1 or 2, wherein the learning value calculation unit determines that a learning condition has been met when the rotation speed passes a predetermined determination rotation speed during the increase of the rotation speed, and updates the torque error learning value based on the deviation.

8. The control device for an internal combustion engine according to claim 7, wherein the learning value calculation unit determines that the learning condition has been met when the rotational speed has been continuously increasing during the determination period and the rotational speed has passed the determination rotational speed.

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