Engine control device and engine control method

Abstract

Engine control unit (ECU 102), with: a target torque calculation unit (203) designed to calculate a target torque of a motor for which torque-based motor control is performed using an estimated torque; and a unit (210) for calculating the estimated torque, which is designed to calculate the estimated torque by performing a primary delay processing on the target torque using a primary delay coefficient equivalent to a time constant calculated for each control cycle on the basis of a change in an actual intake air quantity with respect to a target intake air quantity of the air drawn into the engine, where the unit (210) is used to calculate the estimated torque: a target intake air quantity calculation unit (300) designed to calculate a target intake air quantity based on the target torque input by the target torque calculation unit (203) and an engine speed, and a unit (301) for calculating the primary delay coefficient, designed to calculate the primary delay coefficient equivalent to the time constant calculated on the basis of the target intake air volume and the actual intake air volume, and a primary delay processing unit (302) designed to calculate the estimated torque by performing primary delay processing of the target torque based on the target torque and the primary delay coefficient, wherein the unit (210) for calculating the estimated torque further includes a processing unit (401) for divergence prevention, which is designed to switch the primary delay coefficient calculated by the unit (301) for calculating the primary delay coefficient to a different value in order to prevent a divergence of the primary delay coefficient if the divergence occurs in the calculation of the primary delay coefficient performed by the unit (301) for calculating the primary delay coefficient.

Description

Technical area

[0001] The present invention relates to a motor control device and a motor control method for carrying out torque-based (torque request) motor control. background

[0002] Torque-based (torque-demand) engine control has been used in practice as one of the control methods for an engine with an electronically controlled throttle valve (hereinafter referred to as "electronically controlled throttle valve"). Torque-based engine control is a control method capable of performing throttle valve control, fuel control, ignition control, and similar functions to calculate the engine's target torque based on accelerator pedal opening and engine speed, in order to achieve both the target torque and a target air-fuel ratio.

[0003] Torque control in torque-based engine management comprises two types: low-response torque control, achieved via an intake air volume operation represented by electronic throttle actuation, and high-response torque control, achieved without an intake air volume operation, represented by ignition retardation or fuel cut-off. Two target torque values, the low-response target torque and the high-response target torque, are defined for each torque control method.

[0004] The basis of the torque control system is low-response torque control via the electronic throttle. With low-response torque control, the target torque is set as a low-response target torque. However, if the target torque changes in a complex manner at high engine speeds, it is difficult to generate the engine torque in accordance with the target torque simply by actuating the electronic throttle, due to a delay in the intake air response. In such a situation, where the target torque changes in a complex manner at high engine speeds, the target torque is set as the high-response target torque, and the low-response target torque is set to a value equal to or greater than the high-response target torque.

[0005] Fig. Figure 1 is a diagram showing an example of the time-dependent change of each torque and ignition timing correction amount when the target torque and the estimated torque are equal in a steady state. In this diagram, a horizontal axis represents time and a vertical axis represents torque. The diagram at the top of Fig. Figure 1 shows examples of a target torque with low response 11, a target torque with high response 12 and an estimated torque 13.

[0006] In this specification, a period during which the target low-response torque (e.g., target low-response torque 11) changes by a specified value or more within a defined time is referred to as "transient." Furthermore, a period during which the target low-response torque (e.g., target low-response torque 11) and the estimated torque (e.g., estimated torque 13) are identical is referred to as "continuous." Since the torque does not change in the continuous state, sections 14 and 15 illustrate that both the target low-response torque 11 and the target high-response torque 12 are identical.

[0007] In low-response torque control, engine torque is generated that exceeds the target torque. However, this excess, actually generated torque is adjusted in the decreasing direction, and high-response torque control, such as ignition retard and fuel cut-off, is performed in combination so that the estimated torque 13 matches the target high-response torque 12. An upper diagram of Fig. Figure 1 shows, for example, that a difference 16 arises between the target torque and the torque actually produced. Therefore, the estimated torque 13 is corrected to approximate the target torque 12 with high responsiveness by implementing an ignition delay or fuel advance (MBT: Minimum Advance for the Best Torque) at which the torque is maximized, as a correction amount for the ignition timing. That is, the control of the implementation of the ignition delay or fuel advance is carried out such that the electronic control throttle is opened more with respect to the target torque to be achieved in order to produce the engine torque that exceeds the target torque, while simultaneously eliminating the difference 16 between the target torque and the torque actually produced.

[0008] However, since there is currently no device that directly measures the motor torque, it is necessary to estimate the actual torque produced when implementing low-response torque control, in order to implement both low-response and high-response torque control. The estimated value of the actual torque produced, i.e., the estimated torque, is referred to as estimated torque 13 in the figure on the upper side of Fig. The diagram shown in Figure 1 illustrates this, as described above. The accuracy of the estimated torque 13 then affects the accuracy of the torque control in the transition state.

[0009] Regarding the estimated torque calculation, the state of the art disclosed in PTLs 1 and 2 is known, for example.

[0010] PTL 1 discloses a technique for correcting engine torque by correcting the ignition timing or similar according to a deviation between target torque and corrected estimated torque.

[0011] PTL 2 discloses a technique in which a physical model of the transient behavior with respect to an intake / exhaust system component of an engine is provided and an estimated value for the engine torque is calculated using the physical model of the transient behavior. Citation list for patent literature PTL 1: JP 2002 - 221 068 A PTL 2: JP 2007 - 198 157 A Technical problem

[0012] In the technique described in PTL 1, the estimated torque is calculated by ensuring that there is a very high correlation between the actual air volume and the generated engine torque.

[0013] Fig. Figure 2 is an explanatory diagram showing an example of an estimated torque map 20 for calculating the estimated torque.

[0014] In the estimated torque map 20, which is provided as an example of a conversion map, an engine speed and an actual air volume measured by an airflow sensor are entered. The estimated torque map 20 can then output the estimated torque by calculating the conversion of the entered engine speed and the actual air volume into the engine torque.

[0015] However, it has been found that when applying the technique disclosed in PTL 1 to the aforementioned low-response and high-response torque control, the following problems occur. Immediately after the estimated torque map 20, as in Fig. As shown in Figure 1, where the relationship between the target torque and the estimated torque has been ideally adapted, there is no deviation between the target torque and the estimated torque in the steady state, and the desired torque control can be achieved.

[0016] In reality, however, the ratio between the target torque and the estimated torque can change due to an adaptation error of the estimated torque map 20 or individual fluctuations, environmental changes, and similar factors of the engine control system, as described in Fig. 3 shown.

[0017] Fig. Figure 3 is a diagram showing an example of a time-dependent change in the target torque and the estimated torque, as well as an ignition timing correction amount, when the deviation occurs in the steady state. As in the diagram above. Fig. As shown in Figure 3, the ignition delay or fuel reduction may be implemented at all times if a deviation occurs between the target torque with low response 11 and the target torque with high response 12 and the estimated torque 17, even in the steady state, as indicated by a difference 18 in the lower diagram of Fig. Figure 3 is shown. As a result, defects such as a deterioration in fuel efficiency, an increase in exhaust gas temperature, and torque fluctuations are caused.

[0018] With regard to such a problem, the technique described in PTL 1 requires that the estimated torque be corrected so that, under steady-state conditions, there is no deviation between the target torque and the estimated torque. However, determining a correction amount for the estimated torque is not straightforward, and a desired correction of the estimated torque cannot always be achieved.

[0019] Furthermore, in the technique disclosed in PTL 2, the estimated torque is calculated by performing primary delay processing on the target torque (target torque with low response).

[0020] Fig. Figure 4 is a block diagram showing an example of a primary delay processing unit 21 that performs the calculation of an estimated torque from a low-response set torque. In this technique, the primary delay processing unit 21 outputs the estimated torque by performing primary delay processing on the input low-response set torque using a time constant τ selected from a map stored in a time constant memory unit 22. In the steady state, the low-response set torque, which is the input to the primary delay processing unit 21, and the estimated torque, which is the output of the primary delay processing unit 21, are the same.

[0021] The technique presented in PTL 2 takes into account that, since the target torque with low response and the estimated steady-state torque always coincide, problems such as reduced fuel efficiency and increased exhaust gas temperature can be avoided. However, the technique presented in PTL 2 requires adjustment of the time constant τ.

[0022] Fig. Figure 5 is an explanatory diagram showing an example of the estimated torque 33 and 35 when the actual generated torque traces a complicated torque trajectory with respect to a target torque with low response 31.

[0023] For example, a turbocharged engine traces a torque trajectory where the actual torque produced is complicated in a transitional state with low response torque 31 relative to the target torque. In this case, as shown in an upper diagram (1) of Fig. 5 shows that a turbo lag 32 cannot be expressed by an adjustment with only one time constant τ, and that an estimated torque 33 shown by a dashed line and an actual generated torque 34 differ from each other.

[0024] Therefore, as shown in a lower diagram (2) of Fig. As shown in Figure 5, it is necessary to account for the influence of turbo lag by increasing the number of time constants τ. Diagram (2) shows an example where the number of time constants τ is increased from 1 to 3, from τ1 to τ3. As the number of time constants τ increases, the estimated torque 35 approaches the actual torque produced 34. However, as the number of time constants τ required for adaptation increases, so does the effort required for adaptation, i.e., the time needed to create the map.

[0025] DE 11 2006 002 959 T5 describes a control device for an internal combustion engine in which a torque-controlled quantity, for which a reaction delay has been compensated, is calculated based on the control difference.

[0026] DE 100 33 946 A1 describes a fuel injection control system in which combustion modes are selected depending on operating conditions and the fuel injection quantity is determined depending on the mode. Summary of the invention

[0027] The object of the present invention is to make it possible to apply a torque-based motor control to a motor that has a complicated torque curve. Solution to the problem

[0028] The above problem is solved by the features of the independent claims. An engine control device has the features of claim 1. It comprises a target torque calculation unit that calculates the target torque of an engine for which torque-based engine control is performed using an estimated torque; and a unit for calculating the estimated torque that calculates the estimated torque by performing primary delay processing on the target torque using a primary delay coefficient equivalent to a time constant calculated for each control cycle based on a change in an actual intake air quantity relative to a target intake air quantity of the air drawn into the engine. Claim 1 further specifies features. Advantageous effects of the invention

[0029] According to the present invention, for example, a torque-based motor control can be implemented which can be applied to a motor that exhibits a complex torque curve in the transition state, such as a turbo engine, and which does not require any adjustment of a time constant.

[0030] Problems, configurations and effects other than those described above are illustrated by the description of the following embodiments. Brief description of the drawings Fig. 1] Fig. Figure 1 is a diagram showing an example of the time change of each torque and ignition timing correction amount when a target torque and an estimated torque are the same in a steady state. Fig. 2] Fig. Figure 2 is an explanatory diagram showing an example of an estimated torque map for calculating the estimated torque. Fig. 3] Fig. Figure 3 is a diagram showing an example of a change in the target torque and the estimated torque over time, as well as an ignition timing correction amount, when the deviation occurs in the steady state. Fig. 4] Fig. Figure 4 is a block diagram showing an example of a primary delay processing unit that performs the calculation of an estimated torque from a target torque with low response time. Fig. 5] Fig. Figure 5 is an explanatory diagram that provides an example of the estimated torque when a complicated torque trajectory is drawn with respect to a target torque with low response. Fig. 6] Fig. Figure 6 is a schematic view showing a hardware configuration example of a torque-based motor system compatible with a turbo engine to which a motor control device according to a first embodiment of the present invention is applied. Fig. 7] Fig. Figure 7 is a functional block diagram showing a configuration example of a control system of the torque-based motor system compatible with the turbo engine according to the first embodiment of the present invention. Fig. 8] Fig. Figure 8 is a functional block diagram showing a configuration example of a unit for calculating the estimated torque according to the first embodiment of the present invention. Fig. 9] Fig. Figure 9 is an explanatory diagram showing an example of the calculation content of a primary delay coefficient calculation unit according to the first embodiment of the present invention. Fig. 10] Fig. Figure 10 is a functional block diagram showing a configuration example of a unit for calculating the estimated torque according to a second embodiment of the present invention. Fig. 11] Fig. Figure 11 is a flowchart showing an example of the processing of a divergence prevention processing unit according to the second embodiment of the present invention. Fig. 12] Fig. Figure 12 is a flowchart showing an example of the processing of a primary delay coefficient limiting processing unit according to the second embodiment of the present invention. Fig. 13] Fig. Figure 13 is an explanatory diagram illustrating an aspect in which an actual intake air quantity oscillates with respect to a target intake air quantity according to the second embodiment of the present invention. Fig. 14] Fig. Figure 14 is an explanatory diagram illustrating an aspect of the processing in which a constant delay processing unit reduces the vibration of the current intake air volume according to the second embodiment of the present invention. Fig. 15] Fig. Figure 15 is an explanatory diagram illustrating an aspect in which a primary delay processing unit calculates an estimated intake air quantity by performing primary delay processing on a target intake air quantity according to the second embodiment of the present invention. Fig. 16] Fig. Figure 16 is a functional block diagram showing a configuration example of a unit for calculating the estimated torque according to a third embodiment of the present invention. Fig. 17] Fig. Figure 17 is an explanatory diagram showing an example in which a torque estimation error occurs in a target torque with low response and an estimated torque due to an offset between a target intake air quantity and an actual intake air quantity according to the third embodiment of the present invention. Fig. 18] Fig. Figure 18 is a flowchart showing an example of the processing of an offset processing unit according to the third embodiment of the present invention. Fig. 19] Fig. Figure 19 is a flowchart showing an example of the processing of a primary delay coefficient limiting processing unit with convergence guarantee according to the third embodiment of the present invention. Fig. 20] Fig. Figure 20 is an explanatory diagram showing a configuration example of a hybrid vehicle according to a fourth embodiment of the present invention. Fig. 21] Fig. Figure 21 is a functional block diagram showing a configuration example of a unit for calculating the estimated torque according to the fourth embodiment of the present invention. Fig. 22] Fig. Figure 22 is a functional block diagram showing a configuration example of a stored primary delay coefficient calculation unit according to the fourth embodiment of the present invention. Description of the embodiments

[0031] Embodiments of the present invention are described below with reference to the accompanying drawings. In this description and the drawings, components with essentially the same function or configuration are designated by the same reference numerals, thus avoiding redundant descriptions. [First embodiment]

[0032] Fig. Figure 6 is a schematic view showing a hardware configuration example of a torque-based motor system 1 compatible with a turbo engine to which a motor control device according to a first embodiment is applied. A configuration example of the turbo engine compatible with the torque-based motor system 1 and a method for controlling a motor 10 (motor control method) are described below.

[0033] An engine 10 (an example of an internal combustion engine) is a turbocharged engine with a turbocharger 116. The engine (engine 10) performs torque-based engine control using the estimated torque. The estimated torque used in the torque-based engine control is calculated by an engine control unit (ECU) 102. An intake system of the engine 10 is equipped with a compressor 117, which is a component of the turbocharger 116. Intake air compressed by the compressor 117 flows through an intake pipe 111 and is fed to an intake side of an electronic control throttle 107.

[0034] The electronic throttle valve 107 determines the throttle valve opening by a signal calculated by the ECU 102 based on opening information from the accelerator pedal 101 actuated by a driver, and adjusts the amount of intake air introduced into an intake manifold 109 according to the opening. The ECU 102 is an example of an engine control device.

[0035] When adjusting the intake air volume, the airflow sensor 108, which is located upstream of the compressor 117, measures the current intake air volume of the air drawn into a cylinder of the engine 10. A measurement signal of the current intake air volume is then transmitted from the airflow sensor 108 to the ECU 102.

[0036] The control unit 102 is a type of computer and is configured, for example, by a central processing unit (CPU), read-only memory (ROM), main memory (RAM), and similar components. Each function of the control unit 102 is implemented by executing program code, which is read from the ROM by the CPU. Various values, parameters, and the like are temporarily stored in RAM during processing and read from RAM as needed for further processing. The ROM, in which the program code is stored, is an example of a non-volatile storage medium that can be read by a computer.

[0037] Based on the current intake air volume measured by the airflow sensor 108 and the engine speed obtained from an output signal of a crankshaft angle sensor (not shown), the ECU 102 calculates a suitable fuel injection quantity and fuel injection timing to achieve a target air-fuel ratio.

[0038] The intake manifold 109 is equipped with an injector 103 (an example of a fuel injector). The injector 103 injects fuel in accordance with a fuel injection command issued by the ECU 102. The fuel injected by the injector 103 and the intake air form an air-fuel mixture in the intake manifold 109. The air-fuel mixture is introduced into a combustion chamber 100 from the moment a piston 110, provided for each cylinder of the engine 10, descends and an intake valve 104 opens.

[0039] The intake valve 104 then closes, and the air-fuel mixture compressed as the piston 110 rises is ignited by a spark plug 106 near top dead center of the compression stroke. The ignited air-fuel mixture expands rapidly and pushes the piston 110 downwards to generate engine torque.

[0040] An exhaust stroke then begins from the moment the piston 110 rises and the exhaust valve 105 opens, and exhaust gas from the combustion chamber 100 is routed to an exhaust pipe 112. A turbine 118, which is part of the turbocharger 116, is connected to the exhaust pipe 112. The turbine 118 is set in rotation by the energy of the exhaust gas flowing through the exhaust pipe 112 in order to rotate the coaxial compressor 117 synchronously.

[0041] The torque-based motor system 1, which is compatible with a turbocharged engine, achieves a charging effect by rotating the turbine 118 and the compressor 117 of the turbocharger 116 using the energy of the exhaust gas. The charging effect depends on the amount of exhaust gas.

[0042] It should be noted that if turbine 118 spins excessively, the intake pressure will exceed a setpoint, and engine 10 may be damaged by excessive stress. To prevent this, a wastegate valve control unit 115 controls the opening / closing ratio of a wastegate valve 114, diverts a portion of the exhaust gas towards wastegate 113, and adjusts the turbine rotation. This regulates the intake pressure so that it does not exceed the setpoint. The wastegate valve control unit 115 is a computer-based device and can communicate bidirectionally with the ECU 102.

[0043] Next, a control system for the torque-based motor system 1, compatible with the turbo engine, will be described with reference to Fig. 7 described.

[0044] Fig. Figure 7 is a functional block diagram showing a configuration example of a control system of the torque-based engine system 1 that is compatible with the turbo engine.

[0045] The engine control unit (ECU 102) contains a calculation unit 200 for the maximum torque setpoint, a calculation unit 201 for the required idle torque, a calculation unit 202 for the torque required by the driver, a calculation unit for the target torque (calculation unit 203 for the target torque), a control unit 220 for the air torque, and a control unit 230 for the ignition and fuel torque. The ignition and fuel torque control unit 230 includes a unit for calculating the estimated torque (unit 210 for calculating the estimated torque).

[0046] The calculation unit 200 for the maximum torque setpoint calculates a maximum torque setpoint at a motor speed (motor speed 10) at this time based on an input motor speed signal.

[0047] Unit 201, used to calculate the required idle torque, calculates a torque required to maintain a target idle speed based on the input engine speed signal.

[0048] The calculation unit 202 for the torque required by the driver calculates an engine torque required by a driver on the basis of an accelerator pedal opening obtained from an accelerator pedal opening signal, a maximum torque setpoint calculated by the calculation unit 200 for the maximum torque setpoint and an idle torque calculated by the calculation unit 201 for the required idle torque.

[0049] The target torque calculation unit (target torque calculation unit 203) calculates the target torque of the engine (engine 10) for which torque-based engine control is performed using the estimated torque. Target torque calculation unit 203 takes the required torque from an external system, such as required car travel torque, required transmission torque, and required TRC (Traction Control) torque, in addition to the driver-requested torque calculated by calculation unit 202, and determines a final target torque (engine torque setpoint) taking into account the respective priorities.

[0050] The target torque calculated by the target torque calculation unit 203 is split into a low-response target torque 207 and a high-response target torque 211. The low-response target torque 207 is then transmitted to the air torque control unit 220, which forms a control path for the low-response torque. The high-response target torque 211 is transmitted to the ignition and fuel torque control unit 230, which forms a control path for the high-response torque.

[0051] The air moment control unit 220 includes a target boost pressure calculation unit 205, a target wastegate operation calculation unit 206, a target intake pressure calculation unit 208 and a target throttle valve opening calculation unit 209.

[0052] The target boost pressure calculation unit 205 calculates a target boost pressure that corresponds to the maximum torque target value 204, which was calculated by the calculation unit 200 for the maximum torque target value.

[0053] The target wastegate duty calculation unit 206 calculates a target wastegate duty required to realize the target boost pressure calculated by the target boost pressure calculation unit 205 and transmits the calculation result to a wastegate valve control unit 115 (wastegate control system).

[0054] The target intake pressure calculation unit 208 calculates a target intake pressure that is required to achieve the target torque with low response 207.

[0055] The target throttle opening calculation unit 209 calculates a target throttle opening required to achieve the target intake pressure calculated by the target intake pressure calculation unit 208 and transmits the calculation result to the electronic control throttle 107.

[0056] Next, the ignition and fuel torque control unit 230 is described, which is used when a torque curve that changes at high speed is required from an external device, such as the traction control system.

[0057] The ignition and fuel torque control unit 230 comprises a unit for calculating the estimated torque 210, a unit for calculating the torque correction factor for ignition and fuel operation 212, a unit for selecting the torque operation method 213, a unit for distributing the torque operation amount 214, a unit for calculating the correction amount for ignition timing 215, and a unit for calculating the number of cylinders for fuel cut 216.

[0058] The unit 210 for calculating the estimated torque estimates the engine torque actually generated during engine torque control (actually generated torque) as the estimated torque and calculates the estimated torque (engine torque estimate), which is an index when torque operation is performed by ignition and fuel. Specifically, the unit 210 for calculating the estimated torque calculates the estimated torque, which estimates the actually generated torque, assuming that low-response torque control is performed by the throttle valve and turbocharger. In the present embodiment, the unit for calculating the estimated torque (unit 210 for calculating the estimated torque) calculates a primary delay coefficient (primary delay coefficient 304, which is described later). Fig. 8 is shown), which is equivalent to a time constant (time constant τ) calculated for each control cycle on the basis of a change in the current intake air quantity relative to the target intake air quantity of the air drawn into the engine (engine 10), and calculates the estimated torque by performing a primary delay processing on the target torque based on the primary delay coefficient (primary delay coefficient 304).

[0059] Unit 212, for calculating the ignition and fuel operation torque correction factor, calculates a torque correction factor for ignition and fuel operation, which is an index for the torque operation through ignition and fuel. At this point, Unit 212 calculates a ratio between the estimated torque calculated by Unit 210 for calculating the estimated torque and the target torque 211 with high response input by Unit 203 for calculating the target torque.

[0060] The torque operating procedure selection unit 213 selects a suitable torque operating procedure based on an input drive condition and the ignition and fuel operation torque correction factor calculated by the ignition and fuel operation torque correction factor unit 212. The torque operating procedure includes ignition timing correction or fuel cut-off, and each correction procedure is selected individually or in combination.

[0061] The distribution unit 214 for the torque operating amount distributes a torque operating amount to the calculation unit 215 for the ignition timing correction amount and to the calculation unit 216 for the fuel cut-off cylinder number, based on the torque correction factor for ignition and fuel operation calculated by the calculation unit 212 for the torque correction factor for ignition and fuel operation, and on the torque operating procedure selected by the selection unit 213 for the torque operating procedure.

[0062] The ignition timing correction amount calculation unit 215 calculates an ignition timing correction amount based on the distributed torque correction factor. Therefore, the ignition timing correction amount calculation unit 215 is an example of an ignition timing correction unit that corrects the ignition timing for the ignition of the fuel injected into the cylinder of engine 10, so that the estimated torque becomes the target torque 211 with high response.

[0063] The fuel cut-off cylinder count calculation unit 216 calculates the number of fuel cut-off cylinders based on the distributed torque correction factor. Therefore, the fuel cut-off cylinder count calculation unit 216 is used as an example of the fuel cut-off control unit that performs a fuel cut-off for the cylinders of engine 10, so that the estimated torque becomes the target torque 211 with high responsiveness.

[0064] The ignition timing correction amount, calculated by the ignition timing correction calculation unit 215, is reflected in the ignition control system, and the number of fuel cut-off cylinders, calculated by the fuel cut-off cylinder number calculation unit 216, is reflected in the fuel control system. Therefore, it is possible to achieve the desired engine torque even in transitional conditions.

[0065] Next, a configuration example and an operating example of unit 210 for calculating the estimated torque according to the first embodiment are given with reference to Fig. 8 and Fig. 9 described. Fig. Figure 8 is a functional block diagram showing a configuration example of the Unit 210 for calculating the estimated torque.

[0066] The unit for calculating the estimated torque (unit 210 for calculating the estimated torque) includes a target intake air volume calculation unit (target intake air volume calculation unit 300), a unit for calculating the primary delay coefficient (unit for calculating the primary delay coefficient 301) and a primary delay processing unit (primary delay processing unit 302).

[0067] The target intake air volume calculation unit 300 has a data table (not shown) for the target intake air volume, with the target torque with low response 207 entered by the target torque calculation unit 203 and the engine speed as arguments. The target intake air volume calculation unit (target intake air volume calculation unit 300) then refers to the target intake air volume data table and calculates the target intake air volume (target intake air volume 303) based on the target torque (target torque with low response 207) entered by the target torque calculation unit (target torque calculation unit 203) and the engine speed (engine 10).

[0068] The primary delay coefficient calculation unit (primary delay coefficient calculation unit 301) calculates a primary delay coefficient equivalent to a time constant (time constant τ) calculated for each control cycle based on the target intake air volume (target intake air volume 303) and the actual intake air volume. The calculated time constant τ is output to the primary delay processing unit 302 as the primary delay coefficient 304. The primary delay coefficient calculation unit 301 calculates the time constant τ and the primary delay coefficient 304 in the transition state where the target torque changes by a set value or more within a defined time.This means that the unit for calculating the primary delay coefficient (unit for calculating the primary delay coefficient 301) can calculate the primary delay coefficient (primary delay coefficient 304) if the current intake air volume changes by the set value or more within the specified time.

[0069] The primary delay processing unit (Primary Delay Processing Unit 302) then calculates the estimated torque by performing primary delay processing for the set torque (Set Torque Low Response 207) based on the set torque (Set Torque Low Response 207) and the primary delay coefficient (Primary Delay Coefficient 304). Specifically, the primary delay processing unit (Primary Delay Processing Unit 302) calculates the estimated torque by performing primary delay processing for the set torque (Set Torque Low Response 207) using the primary delay coefficient (Primary Delay Coefficient 304), which is calculated in the transition state where the set torque (Set Torque Low Response 207) changes by the set value or more within the specified time.Additionally, the primary delay processing unit (Primary Delay Processing Unit 302) can calculate the target torque (Low Response Target Torque 207) as the estimated steady-state torque when the target intake air volume and the actual intake air volume are equal.

[0070] This section describes the calculation content of the primary delay coefficient calculation unit 301.

[0071] Fig. Figure 9 is an explanatory diagram that illustrates an example of the calculation content of the primary delay coefficient calculation unit 301. In the diagram shown... Fig. In diagram 9, a horizontal axis represents time and a vertical axis represents the amount of intake air.

[0072] The diagram (1) in Fig. Figure 9 illustrates a relationship between a target intake air quantity X'(t) and an actual intake air quantity Y'(t). A lower part of diagram (1) in Fig. Figure 9 illustrates an aspect of the transition state in which the actual intake air quantity Y'(t) approaches the target intake air quantity X'(t), and an upper part of diagram (1) illustrates an enlarged view of area 310, which represents an aspect of the actual intake air quantity Y'(t) in the transition state. The target intake air quantity X'(t) is a value calculated by the target intake air quantity calculation unit 300 and corresponds to the one in Fig. The target intake air volume shown in section 8 is 303. The actual intake air volume Y'(t) is a value that differs from the one shown in Fig. The measurement is taken by the airflow sensor 108 shown in section 6.

[0073] As shown in the following equation (1), the primary delay coefficient calculation unit 301 calculates a primary delay coefficient α with respect to the intake air quantity from the target intake air quantity X'(t) and the actual intake air quantity Y'(t) for each control cycle. [Equation 1] α=Y'(t)−Y'(t−1)X'(t)−Y'(t−1)

[0074] In the following description, a physical quantity at time t is referred to as an "instantaneous value" and a physical quantity at time t-1 as a "previous value". For example, in equation (1), the primary delay coefficient α is calculated based on an instantaneous value X'(t) of the target intake air quantity, an instantaneous value Y'(t) of the actual intake air quantity, and a previous value Y'(t-1) of the actual intake air quantity. The primary delay coefficient α corresponds to that in Fig. 8 primary delay coefficients shown 304.

[0075] Diagram (2) in Fig. Figure 9 illustrates a relationship between the target low-response torque X(t) and the estimated torque Y(t). A lower part of diagram (2) in Fig. Figure 9 illustrates an aspect of the transition state in which the estimated torque Y(t) approaches a target torque with low response X(t), and an upper part of diagram (2) illustrates an enlarged view of region 311, which represents an aspect of the estimated torque Y(t) in the transition state.

[0076] When the primary delay coefficient α is calculated by the primary delay coefficient calculation unit 301, as shown in diagram (1) in Fig. As described in section 9, the estimated torque Y(t) is calculated using this primary delay coefficient α. Therefore, the primary delay processing unit 302, as illustrated in the following equation (2), calculates an instantaneous value Y(t) of the estimated torque for each control cycle based on the primary delay coefficient α calculated by equation (1), the target low-response torque X(t), and the previous value Y(t-1) of the estimated torque. [Equation 2] Y(t)=αX(t)+(1−α)Y(t−1)

[0077] As described above, the primary delay coefficient α calculated using equation (1) and used in equation (2) is expressed as primary delay coefficient 304, which is calculated by the primary delay coefficient calculation unit 301 and output to the primary delay processing unit 302, as shown in Fig. Figure 8 illustrates the primary delay coefficient 304, which is a value expressing one aspect of the change in the current intake air volume. The primary delay coefficient α is then a value obtained by discretizing the time constant τ with a control cycle ΔT, as shown in equation (3) below. Calculating the primary delay coefficient α and using it to calculate the estimated torque Y(t) is equivalent to calculating the time constant τ and using it to calculate the estimated torque Y(t). [Equation 3] α=ΔTτ+ΔT

[0078] The ECU 102 according to the present embodiment includes the unit 210 for calculating the estimated torque, as shown in Fig. Figure 7 illustrates this. Unit 210 for calculating the estimated torque calculates the primary delay coefficient 304, which is used for primary delay processing, based on the change in the current intake air volume of the air drawn into the engine 10 in Unit 301 for calculating the primary delay coefficient. Then, Unit 210 for calculating the estimated torque can calculate the estimated torque by performing the primary delay processing through Primary Delay Processing Unit 302, based on the target low-response torque 207 and the primary delay coefficient 304.

[0079] As in Fig. As shown in Figure 1, the unit 210 can calculate the estimated torque by performing the primary delay processing on the low-response target torque 207 calculated by the unit 203 for calculating the target torque, if the low-response target torque 207 changes by the set value or more within the specified time. If the low-response target torque 207 changes by the set value or more within the specified time, this means that the low-response target torque 207 is no longer in a steady state.Then, unit 210 calculates the primary delay coefficient 304, used for primary delay processing, based on the change in the current intake air volume of the air drawn into the motor 10 when the target low-response torque 207 changes by the set value or more within the specified time or during the transition period. The primary delay processing unit 302 can then calculate the estimated torque using the primary delay coefficient 304.

[0080] The ignition timing correction unit (ignition timing correction amount calculation unit 215) corrects the ignition timing for the ignition of the fuel injected into the cylinder of the engine (engine 10) so that the estimated torque becomes the target torque (target torque with high response 211). By correcting the ignition timing, it is possible to increase or decrease the estimated torque.

[0081] Furthermore, the fuel cut-off control unit (fuel cut-off cylinder count calculation unit 216) performs a fuel cut-off for the engine cylinders (engine 10), so that the estimated torque becomes the target torque (high-response target torque 211). For example, the torque can be reduced by performing the fuel cut-off for a specific cylinder out of a large number of cylinders.

[0082] Furthermore, the fuel injection quantity control unit (ECU 102) corrects the fuel injection quantity of the fuel injector (injector 103) that sends fuel to the engine cylinders (engine 10), so that the estimated torque becomes the target torque (high-response target torque 211). By increasing or decreasing the fuel injection quantity, the ECU 102 increases or decreases the estimated torque, and it becomes possible to control the estimated torque so that it approaches the target torque.

[0083] Ignition timing correction, fuel cut-off, or fuel injection quantity correction are performed, for example, by the ECU 102 alone or in combination.

[0084] The unit 210 for calculating the estimated torque according to the first embodiment described above enables the provision of an engine control device (ECU 102) and a control method that uses torque estimation logic which does not require adjustment of the time constant. At this point, the ECU 102 automatically calculates the primary delay coefficient 304 of the torque based on the change in the current intake air volume for each control cycle and calculates the estimated torque by performing the primary delay processing based on the target torque and the primary delay coefficient 304.

[0085] Therefore, even when drawing a complex torque trajectory in the transition state, as in a turbocharged engine, the ECU 102 does not need to increase the number of time constants to adjust the primary delay processing parameters. Furthermore, problems such as reduced fuel efficiency, increased exhaust gas temperature, and torque fluctuations due to a discrepancy between the target torque and the estimated torque in steady state do not occur. Because the ECU 102 can accurately calculate the estimated torque based on the automatically calculated primary delay coefficient 304, suitable torque-based torque control becomes possible. [Second embodiment]

[0086] Next, a configuration example and an operating example of the unit for calculating the estimated torque according to the second embodiment will be presented with reference to the Fig. 10 to 15 described.

[0087] First, with reference to Fig. 13 describes an aspect in which the current intake air volume oscillates in small steps.

[0088] Fig. Figure 13 is an explanatory diagram illustrating an aspect where an actual intake air quantity 321 oscillates with respect to a target intake air quantity 320.

[0089] In a transitional state, where the current intake air quantity 321 changes towards the target intake air quantity 320, the current intake air quantity 321 tends to oscillate, as in Fig. Figure 13 shows that if the current intake air volume 321, which is used to calculate the primary delay coefficient α, oscillates, the primary delay coefficient α may not be calculated correctly.

[0090] Furthermore, the primary delay coefficient α calculated by the primary delay coefficient calculation unit 301 according to the first embodiment involves a division, as shown in equation (1) mentioned above. With continuity, since the target intake air quantity X'(t) and the actual intake air quantity Y'(t) have almost the same value (X'(t) = Y'(t-1)) and therefore a denominator of equation (1) becomes zero or assumes an extremely small value, a mathematical contradiction or divergence of the primary delay coefficient α can occur.

[0091] Therefore, the unit 210A is used to calculate the estimated torque ( Fig. 10) according to the second embodiment, a configuration in which the processing to prevent the mathematical contradiction and divergence in equation (1) and to reduce the vibration of the current intake air quantity of unit 210 is added for calculating the estimated torque according to the first embodiment.

[0092] A configuration example of unit 210A for calculating the estimated torque according to the second embodiment is described.

[0093] Fig. Figure 10 is a functional block diagram showing a configuration example of a 210A unit for calculating the estimated torque.

[0094] The unit for calculating the estimated torque (unit 210A for calculating the estimated torque) includes, in addition to the unit 210 for calculating the estimated torque according to the first embodiment, a constant delay processing unit (constant delay processing unit 400), a divergence prevention processing unit (divergence prevention processing unit 401), a primary delay coefficient limiting processing unit (primary delay coefficient limiting processing unit 402) and a second primary delay processing unit (primary delay processing unit 404).

[0095] The constant delay processing unit (constant delay processing unit 400) performs filter processing with a constant delay coefficient to reduce the vibration of the input current intake air volume. The constant delay processing unit 400 outputs the current intake air volume with reduced vibration to the primary delay coefficient calculation unit 301.

[0096] The primary delay coefficient calculation unit (primary delay coefficient calculation unit 301) calculates the primary delay coefficient (primary delay coefficient 304) based on the target intake air volume (target intake air volume 303), the actual intake air volume with which filter processing is performed, and the estimated intake air volume (estimated intake air volume 403) input by the second primary delay processing unit (primary delay processing unit 404).Here, the target intake air volume 303 is input to the primary delay coefficient calculation unit 301 by the target intake air volume calculation unit 300, the current intake air volume on which the filter processing is performed is input by the constant delay processing unit 400, and a previous value of the estimated intake air volume 403 is input by the primary delay processing unit 404. Then, the primary delay coefficient calculation unit 301 outputs the primary delay coefficient 304 to the divergence prevention processing unit 401.

[0097] If the primary delay coefficient (Primary Delay Coefficient 304) deviates during the calculation of the primary delay coefficient (Primary Delay Coefficient 304) performed by the primary delay coefficient calculation unit (Primary Delay Coefficient Calculation Unit 301), the divergence prevention processing unit (Divergence Prevention Processing Unit 401) switches the primary delay coefficient (Primary Delay Coefficient 304) input by the primary delay coefficient calculation unit (Primary Delay Coefficient Calculation Unit 301) to a different value and prevents the divergence of the primary delay coefficient (Primary Delay Coefficient 304). At this point, the divergence prevention processing unit 401 switches an output of the input primary delay coefficient 304 according to a Fig. 11 condition determination shown. For example, the divergence prevention processing unit 401 selects, depending on the condition determination, whether the input primary delay coefficient 304 is output as is, or whether "0" is output to the primary delay coefficient limitation processing unit 402.

[0098] The Primary Delay Coefficient Limiting Processing Unit (Primary Delay Coefficient Limiting Processing Unit 402) limits the primary delay coefficient (primary delay coefficient 304) input by the divergence prevention processing unit (divergence prevention processing unit 401) and outputs it to the primary delay processing unit (Primary Delay Processing Unit 302). At this point, the Primary Delay Coefficient Limiting Processing Unit 402 limits the output by toggling the output through the state determination of whether it is in the continuous state and the state determination of whether the primary delay coefficient 304 input by the divergence prevention processing unit 401 is 0 or greater and 1 or less.For example, depending on the state determination, a selection is made as to whether the primary delay coefficient 304 input by the divergence prevention processing unit 401 is output as is, or whether "0" or "1" is output. If the primary delay coefficient 304 input by the divergence prevention processing unit 401 is a negative value less than 0, "0" is selected as the output. The output of the primary delay coefficient 304, which is limited by the primary delay coefficient limiting processing unit 402, is input into the primary delay processing units 302 and 404.

[0099] The second primary delay processing unit (primary delay processing unit 404) performs the primary delay processing of the target intake air quantity (target intake air quantity 303) and calculates the estimated intake air quantity of the engine (engine 10) based on the target intake air quantity (target intake air quantity 303) and the primary delay coefficient (primary delay coefficient 304), which is limited by the primary delay coefficient limiting processing unit (primary delay coefficient limiting processing unit 402). At this time, the primary delay processing unit 404 performs the primary delay processing of the target intake air quantity 303 (target intake air quantity X'(t)) by using the target intake air quantity 303 and the limited primary delay coefficient 304 as inputs, and produces a previous value Y''(t-1) of the estimated intake air quantity 403.Then the primary delay processing unit 404 outputs the previous value Y''(t-1) of the estimated intake air quantity 403 to the primary delay coefficient calculation unit 301.

[0100] Again, the unit for calculating the primary delay coefficient (unit for calculating the primary delay coefficient 301) calculates the primary delay coefficient 304. This time, the unit for calculating the primary delay coefficient (unit for calculating the primary delay coefficient 301) calculates the primary delay coefficient (primary delay coefficient 304) using the previous value of the estimated intake air volume (previous value Y''(t-1) of the estimated intake air volume 403) instead of the previous value of the current intake air volume.Therefore, the calculation unit 301 for the primary delay coefficient automatically calculates the primary delay coefficient 304 based on the input target intake air quantity 303 (target intake air quantity X'(t)), the instantaneous value of the current intake air quantity output by the constant delay processing unit 400, and the previous value Y''(t-1) of the estimated intake air quantity 403.

[0101] The primary delay processing unit 302 performs primary delay processing of the target torque with low response 207 by taking as input the primary delay coefficient 304, which is limited by the primary delay coefficient limiting processing unit 402, and outputs the calculated estimated torque to the unit 212 for calculating the torque correction factor for ignition and fuel operation.

[0102] Here is a processing example of the divergence prevention processing unit 401 and the primary delay coefficient limitation processing unit 402 with reference to the Fig. 11 and Fig. 12 is described, and then a processing example of the constant delay processing unit 400 and the primary delay processing unit 404 is described.

[0103] Fig. Figure 11 is a flowchart showing an example of the processing of the divergence prevention processing unit 401.

[0104] The divergence prevention processing unit 401 determines whether a condition is met that an absolute value of "target intake air volume - previous value of current intake air volume" is less than an absolute value of "target intake air volume - instantaneous value of current intake air volume", or a condition that "instantaneous value of current intake air volume - previous value of current intake air volume" is less than "1" (S1). The absolute value is determined for each condition in step S1 to prevent any calculated value from becoming negative. Here, the condition that the absolute value of "target intake air volume - previous value of current intake air volume" is less than the absolute value of "target intake air volume - instantaneous value of current intake air volume" is used to limit the primary delay coefficient 304, so that, for example,the primary delay coefficient 304 does not drop too drastically due to a sudden fluctuation in the current intake air volume.

[0105] If either of the two conditions in step S1 is met (YES in S1), the divergence prevention processing unit 401 outputs the primary delay coefficient 304 to the primary delay coefficient limitation processing unit 402 as "0" (S2) and terminates processing. If neither condition is met (NO in S1), the divergence prevention processing unit 401 outputs the primary delay coefficient 304, which was input by the primary delay coefficient calculation unit 301, to the primary delay coefficient limitation processing unit 402 as it is (S3) and terminates processing.

[0106] Fig. Figure 12 is a flowchart showing an example of the processing of the Primary Delay Coefficient Limiting Processing Unit 402.

[0107] The Primary Delay Coefficient Limiting Processing Unit 402 determines whether it is in a continuous state (S11) or not. If it is in a continuous state (YES in S11), the Primary Delay Coefficient Limiting Processing Unit 402 outputs "1" as the Primary Delay Coefficient 304 to the Primary Delay Processing Unit 404 (S13) and terminates processing. If it is not in a continuous state (NO in S11), it determines whether the Primary Delay Coefficient 304 input by the Divergence Prevention Processing Unit 401 exceeds "1" (S12) or not. If the primary delay coefficient input by the divergence prevention processing unit 401 exceeds "1" (YES in S12), the primary delay coefficient limitation processing unit 402 outputs "1" to the primary delay processing unit 404 (S13) and terminates processing.

[0108] If the primary delay coefficient 304 input by the divergence prevention processing unit 401 is "1" or less (NO in S12), the primary delay coefficient limiting processing unit 402 determines whether the primary delay coefficient 304 input by the divergence prevention processing unit 401 is less than "0" or not (S14). If the primary delay coefficient 304 input by the divergence prevention processing unit 401 is less than "0" (YES in S14), the primary delay coefficient limiting processing unit 402 outputs "0" to the primary delay processing unit 404 (S15) and terminates processing.

[0109] If the primary delay coefficient 304 input by the divergence prevention processing unit 401 is "0" or greater (NO in S14), the primary delay coefficient limitation processing unit 402 outputs the input primary delay coefficient 304 to the primary delay processing units 302 and 404 as is (S16) and terminates processing. That is, in step S16, if the primary delay coefficient 304 input by the divergence prevention processing unit 401 is "0 or greater and less than 1", the input is output as is.

[0110] Next, the processing of the constant delay processing unit 400 and the primary delay processing unit 404 will be described with reference to the Fig. described.

[0111] Fig. Figure 14 is an explanatory diagram illustrating one aspect of the processing where the constant delay processing unit 400 reduces the oscillation of the current intake air volume.

[0112] As described above, the constant delay processing unit 400 performs filter processing with the delay coefficient as a constant to reduce the vibration of the current intake air volume. Therefore, the constant delay processing unit 400, for example, performs filter processing with the delay coefficient as a constant, as shown in equation (4) below, with respect to the current intake air volume input to unit 210A for calculating the estimated torque, and obtains the instantaneous value of the current intake air volume. [Equation 4] Current value of the constant delay processing unit output = constant * current intake air volume + (1 - constant) * previous value of the constant delay processing unit output

[0113] As in Fig. As shown in Figure 14, a current intake air volume 321, including the vibration input from the left side of the constant delay processing unit 400, is output as a current intake air volume 322, the vibration of which is reduced by the filter processing of the constant delay processing unit 400. The current intake air volume 322 with reduced vibration is input into the primary delay coefficient calculation unit 301.

[0114] In the present embodiment, the constant delay processing unit 400 performs the filter processing based on the current intake air volume, but the filter processing can also be performed based on the primary delay coefficient 304, which is calculated based on the current intake air volume. In this case, the constant delay processing unit 400 is positioned between the primary delay coefficient calculation unit 301 and the divergence prevention processing unit 401.

[0115] As in Fig. As shown in Figure 14, the filter processing performed by the constant delay processing unit 400 reduces the vibration of the current intake air volume, but does not eliminate it completely. Furthermore, when calculating equation (1), which is performed by the primary delay coefficient calculation unit 301, there are two types of terms, including the vibration, because the instantaneous value Y'(t) and the previous value Y'(t-1) of the current intake air volume are used. Therefore, the primary delay coefficient calculation unit 301 may not be able to correctly calculate the primary delay coefficient 304.

[0116] In the calculation of the primary delay coefficient 304, which is performed by the primary delay coefficient calculation unit 301 to reduce the terms with oscillations, a previous value Y''(t-1) of the estimated intake air quantity 403 is used instead of the previous value Y'(t-1) of the current intake air quantity, which is used in equation (5) of Fig. 15 is shown. However, equation (5) must satisfy equation (6). [Equation 5] Y''(t)=αX'(t)+(1−α)Y''(t−1) [Equation 6] However, α=Y'(t)−Y''(t−1)X'(t)−Y''(t−1)

[0117] Fig. Figure 15 is an explanatory diagram illustrating an aspect where the primary delay processing unit 404 calculates an estimated intake air volume by performing primary delay processing on a target intake air volume.

[0118] The primary delay processing unit 404 performs primary delay processing using equations (5) and (6) with respect to the input target intake air quantity 303 (target intake air quantity X'(t)). The primary delay processing unit 404 then outputs the instantaneous value Y''(t) of the estimated intake air quantity 403. The previous value Y''(t-1) of the estimated intake air quantity 403 is input to the primary delay coefficient calculation unit 301 and used as the previous value Y'(t-1) of the current intake air quantity in equation (1).

[0119] The primary delay coefficient 304, calculated by the primary delay coefficient calculation unit 301, is output again to the divergence prevention processing unit 401.

[0120] The primary delay coefficient 304, which undergoes divergence prevention processing by the divergence prevention processing unit 401, is then limited by the primary delay coefficient limiting processing unit 402 and output to the primary delay processing unit 302 as the primary delay coefficient 304. The primary delay processing unit 302 can then calculate the estimated torque by performing primary delay processing based on the target low-response torque 207 and the primary delay coefficient 304, whose output is limited.

[0121] The unit 210A for calculating the estimated torque according to the second embodiment described above calculates the target torque with low response 207 as the estimated steady-state torque. At this point, the unit 210A for calculating the estimated torque switches the primary delay coefficient 304 if a mathematical contradiction or divergence occurs in the calculation using equation (1) to obtain the primary delay coefficient 304. This prevents the mathematical contradiction or divergence in the calculation of the primary delay coefficient 304.

[0122] Furthermore, the constant delay processing unit 400, included in unit 210A for calculating the estimated torque, can perform filter processing to reduce the vibration of the current intake air volume. Therefore, the vibration is reduced even if the input current intake air volume contains vibration. Additionally, unit 301, used to calculate the primary delay coefficient 304, calculates the primary delay coefficient 304 by using the previous value Y''(t-1) of the estimated intake air volume 403 instead of the previous value Y'(t-1) of the current intake air volume. This reduces the degradation in calculation accuracy due to vibration of the current intake air volume used by the estimated torque calculation unit 210A for calculating the primary delay coefficient 304.

[0123] As described above, the unit 210A for calculating the estimated torque according to the second embodiment improves the stability of the calculation without sudden changes or vibrations in the calculated value of the primary delay coefficient 304 in the steady state and the transition state. Furthermore, the deterioration of the calculation accuracy due to vibrations in the current intake air volume can be reduced. [Third embodiment]

[0124] Next, a configuration example and an operating example of a unit for calculating the estimated torque according to a third embodiment will be presented with reference to the Fig. Described in sections 16 to 19.

[0125] First, with reference to Fig. 17 describes a point where the target intake air quantity and the actual intake air quantity are offset.

[0126] Fig. Figure 17 is an explanatory diagram showing an example in which a torque estimation error 343 occurs in a target torque with low response 341 and an estimated torque 342 due to an offset 333 between a target intake air quantity 331 and an actual intake air quantity 332.

[0127] The diagram (1) of Fig. Figure 17 shows an aspect where the offset 333 occurs between the target intake air quantity 331 and the actual intake air quantity 332. As described above, the target intake air quantity 331 and the actual intake air quantity 332 should be the same under steady-state conditions. However, due to the influence of sensor errors, environmental changes, or similar factors, an offset 333 between the target intake air quantity 331 and the actual intake air quantity 332 can occur under steady-state conditions. Since, in this case, the actual intake air quantity 332 does not become the value represented by a dashed line 334, but is a value lower by the offset 333, the target intake air quantity 331 and the actual intake air quantity 332 deviate from each other under steady-state conditions.

[0128] Diagram (2) in Fig. Figure 17 illustrates an aspect where the torque estimation error 343 occurs in the estimated torque 342, which is calculated by changing the current intake air volume. As shown in diagram (1), the estimated torque 342, which does not reach the target low-response torque 341, is obtained due to the influence of the offset 333, which is generated between the target intake air volume 331 and the current intake air volume 332. The torque estimation error 343, represented by a vertical line, then remains in the estimated torque 342 in the transition state. Therefore, when the steady state is reached, the torque actually generated must be changed abruptly so that the estimated torque 342 matches the target low-response torque 341.If a torque estimation error 343 occurs in this way, the accuracy of the torque estimation with respect to the estimated torque 342 deteriorates. Therefore, an offset processing is added to unit 210A for calculating the estimated torque according to the second embodiment to reduce the deterioration of the torque estimation accuracy.

[0129] Then, in the present embodiment, as shown in diagram (2) of Fig. As shown in Figure 17, the occurrence of the offset 333 prevents the estimated torque 342 from converging to the target torque with low response 341 by the end of the settling period. Therefore, the processing of the switching of a lower limit of the primary delay coefficient 304 by a condition determination is added to the unit 210A for calculating the estimated torque according to the second embodiment.

[0130] Fig. Figure 16 is a functional block diagram showing a configuration example of a unit 210B for calculating the estimated torque according to the third embodiment.

[0131] The unit for calculating the estimated torque (unit 210B for calculating the estimated torque) comprises an offset processing unit (offset processing unit 500) added to the unit 210A for calculating the estimated torque according to the second embodiment, and further comprises a second primary delay coefficient limiting processing unit (primary delay coefficient limiting processing unit 501 with convergence guarantee) which replaces the primary delay coefficient limiting processing unit 402.

[0132] Here, the constant delay processing unit (constant delay processing unit 400), which is included in unit 210B for calculating the estimated torque, performs filter processing with the delay coefficient as a constant to reduce the vibration of the current intake air volume. Afterwards, the constant delay processing unit 400 outputs the current intake air volume with reduced vibration to the offset processing unit 500.

[0133] The Offset Processing Unit 500 performs offset processing to add or subtract an offset value from the input current intake air volume during the transition period, starting from the beginning of the transition period. At this point, the Offset Processing Unit (Offset Processing Unit 500) performs offset processing on the current intake air volume, on which the filter processing is performed by the Constant Delay Processing Unit (Constant Delay Processing Unit 400), using the offset value obtained in the steady state when the target intake air volume and the current intake air volume are equal. The Offset Processing Unit 500 then outputs the offset current intake air volume, on which the offset processing is performed, to the Primary Delay Coefficient Calculation Unit 301.At the same time, the offset processing unit 500 outputs the offset value 503 used for offset processing to the primary delay coefficient limiting processing unit 501 with convergence guarantee.

[0134] The primary delay coefficient calculation unit (primary delay coefficient calculation unit 301) calculates the primary delay coefficient (primary delay coefficient 304) based on the target intake air quantity, the current intake air quantity on which the offset processing is performed, and the estimated intake air quantity of the engine (engine 10).

[0135] Since the processing of the divergence prevention processing unit 401 is the same as that with reference to Fig. For the processing described in section 10, a detailed description is omitted.

[0136] The second primary delay coefficient limiting processing unit (primary delay coefficient limiting processing unit 501 with convergence guarantee) has a convergence guarantee function for limiting (converging) the primary delay coefficient (primary delay coefficient 304) by switching the lower limit of the primary delay coefficient (primary delay coefficient 304), whose divergence is prevented by the divergence prevention processing unit (divergence prevention processing unit 401), to a different value.At the time of convergence of the primary delay coefficient 304, the primary delay coefficient limiting processing unit 501 with convergence guarantee switches the lower limit of the primary delay coefficient 304 according to information such as an input offset value 503, whether the target intake air quantity 303 is increasing or not, and an elapsed time from the beginning of the transition period, in addition to the processing to limit the primary delay coefficient, which is carried out by the primary delay coefficient limiting processing unit 402 according to the second embodiment. The primary delay coefficient 304 is then output by the primary delay coefficient limiting processing unit 501 with convergence guarantee to the primary delay processing units 302 and 404.

[0137] The second primary delay processing unit (primary delay processing unit 404) performs the primary delay processing of the target intake air volume and calculates the estimated intake air volume (estimated intake air volume 403) of the engine (engine 10) based on the target intake air volume and the primary delay coefficient (primary delay coefficient 304), which is limited by the second primary delay coefficient limiting processing unit (primary delay coefficient limiting processing unit 501 with convergence guarantee). The second primary delay processing unit (primary delay processing unit 404) then outputs the estimated intake air volume (estimated intake air volume 403) to the primary delay coefficient calculation unit (primary delay coefficient calculation unit 301).The primary delay coefficient calculation unit 301 then performs the calculation of the primary delay coefficient 304 using the estimated intake air quantity 403, which is input by the primary delay processing unit 404.

[0138] The primary delay processing unit 302 performs primary delay processing of the target torque with low response 207 by using the primary delay coefficient 304, which is limited by the primary delay coefficient limiting processing unit 501 with convergence guarantee and whose lower limit has been switched as an input. The primary delay processing unit 302 then outputs the calculated estimated torque to the unit 212 for calculating the torque correction factor for ignition and fuel operation.

[0139] Here is a processing example of the offset processing unit 500 and the primary delay coefficient limiting processing unit 501 with convergence guarantee, with reference to Fig. 18 and Fig. 19 described. Fig. Figure 18 is a flowchart showing an example of the processing of the Offset Processing Unit 500.

[0140] First, the offset processing unit 500 determines whether the target intake air quantity 303 has changed or not (S21). If it is determined that the target intake air quantity 303 has not changed (NO in S21), the offset processing unit 500 repeats the processing in step S21 and continues to monitor the target intake air quantity 303.

[0141] If, however, it is determined that the target intake air quantity 303 has changed (YES in S21), the offset processing unit 500 holds the offset value 503 immediately before the change in the target intake air quantity 303, i.e., in a steady state (S22). Next, the offset processing unit 500 determines whether the target low-response torque 31 has entered a transition state or not (S23). If it is determined that the target low-response torque 31 is not in a transition state (NO in S23), the offset processing unit 500 repeats the processing in step S23 and continues the condition monitoring.

[0142] If, on the other hand, it is determined that the target torque with low response 31 is in the transition state (YES in S23), the offset processing unit 500 calculates the offset intake air volume 502. Here, the offset intake air volume 502 is obtained by adding or subtracting the offset value 503 from the current intake air volume. The offset value 503 therefore takes on a positive or negative value. The offset processing unit 500 then outputs the calculated offset intake air volume 502 to the primary delay coefficient calculation unit 301. Furthermore, the offset processing unit 500 outputs the offset value 503 used for calculating the offset processing to the primary delay coefficient limitation processing unit 501 with convergence guarantee (S24) and terminates the processing.

[0143] Fig. Figure 19 is a flowchart showing an example of the processing of the Primary Delay Coefficient Limiting Processing Unit 501 with Convergence Guarantee.

[0144] First, the primary delay coefficient limiting processing unit 501 with convergence guarantee performs the primary delay coefficient limiting processing that is carried out by the primary delay coefficient limiting processing unit 402 according to the second embodiment (S31). Next, the primary delay coefficient limiting processing unit 501 with convergence guarantee increases or decreases the target torque with low response 207 and determines a condition based on the lower limit or the like (S32). In the present embodiment, there are four conditions, and when one of the conditions is met, the next processing step is performed. Note that the numerical values ​​attached to the arrows to steps S33, S35, S37, and S39 represent the condition numbers assigned to each condition.If one of the conditions is met, the next processing step corresponding to the condition number is carried out.

[0145] Each value shown in the image is described. • A lower limit of 1 is an output value from a data table in which an absolute value of the offset value 503 is entered, and is a value close to 0 in the range of 0 or more and 1 or less. • A lower limit 2 is a calculated value of a quadratic function for an elapsed time from the beginning of the transient phase and is a value that moves in such a way that it gradually increases from 0. • A lower limit 3 = 0. • A lower limit of 4 = the lower limit of 1.

[0146] As shown in condition 1 of step S32, when the target torque with low response 207 increases and the lower limit 2 is greater than the lower limit 1, the primary delay coefficient limiting processing unit 501 with convergence guarantee determines whether the primary delay coefficient 304, at which the primary delay coefficient limiting processing is performed, is the lower limit 1 or greater (S33). If it is determined that the primary delay coefficient 304 is the lower limit 1 or greater (YES in S33), the primary delay coefficient limiting processing unit 501 with convergence guarantee outputs an input as is (S41) and terminates the processing. Here, an output destination in step S41 is the primary delay processing unit 302 and 404, as shown in Fig. 16 shown.

[0147] On the other hand, if it is determined that the primary delay coefficient 304 is less than the lower limit 1 (NO in S33), the primary delay coefficient limiting processing unit 501 with convergence guarantee outputs the lower limit 1 to the primary delay processing units 302 and 404 (S34) and terminates the processing.

[0148] As described in condition 2 of step S32, when the target torque with low response 207 increases and the lower limit 1 ≥ the lower limit 2, the primary delay coefficient limiting processing unit 501 with convergence guarantee determines whether the primary delay coefficient 304, at which the primary delay coefficient limiting processing is performed, is the lower limit 2 or higher (S35). If it is determined that the primary delay coefficient 304 is the lower limit 2 or higher (YES in S35), the primary delay coefficient limiting processing unit 501 with convergence guarantee outputs an input as is (S41) and terminates the processing.On the other hand, if it is determined that the primary delay coefficient 304 is less than the lower limit 2 (NO in S35), the primary delay coefficient limiting processing unit 501 with convergence guarantee outputs the lower limit 2 to the primary delay processing units 302 and 404 (S36) and terminates the processing.

[0149] As described in condition 3 of step S32, the primary delay coefficient limiting processing unit 501 with convergence guarantee determines, when the target torque with low response 207 decreases and the elapsed time since the start of the settling period is less than a threshold (start of the transition state), whether the primary delay coefficient 304, at which the primary delay coefficient limiting processing is performed, is the lower limit of 3 or higher (S37). If it is determined that the primary delay coefficient 304 is the lower limit of 3 or higher (YES in S37), the primary delay coefficient limiting processing unit 501 with convergence guarantee outputs an input as is (S41) and terminates the processing.On the other hand, if it is determined that the primary delay coefficient 304 is less than the lower limit 3 (NO in S37), the primary delay coefficient limiting processing unit 501 with convergence guarantee outputs the lower limit 3 to the primary delay processing units 302 and 404 (S38) and terminates the processing.

[0150] As described in condition 4 of step S32, when the target torque with low response 207 decreases and the time elapsed since the start of the settling phase is the threshold or greater (the midpoint to the end of the transition state), the primary delay coefficient limiting processing unit 501 with convergence guarantee determines whether the primary delay coefficient 304, at which the primary delay coefficient limiting processing is performed, has a lower limit of 4 or greater (S39). If it is determined that the primary delay coefficient 304 has a lower limit of 4 or greater (YES in S39), the primary delay coefficient limiting processing unit 501 with convergence guarantee outputs an input as is (S41) and terminates the processing.On the other hand, if it is determined that the primary delay coefficient 304 is less than the lower limit 4 (NO in S39), the primary delay coefficient limiting processing unit 501 with convergence guarantee outputs the lower limit 1 to the primary delay processing units 302 and 404 (S40) and terminates processing.

[0151] Unit 210B, used to calculate the estimated torque according to the third embodiment described above, performs offset processing on the current intake air volume to reduce the degradation in calculation accuracy due to the offset in the current intake air volume used to calculate the primary delay coefficient 304. Furthermore, unit 210B switches the lower limit of the primary delay coefficient 304 to prevent the estimated torque, which is the calculation result, from converging to the target low-response torque 207 due to the offset in the current intake air volume used to calculate the primary delay coefficient 304.

[0152] As described above, the 210B unit for calculating the estimated torque according to the third embodiment can reduce the deterioration in the calculated accuracy of the estimated torque due to the offset of the current intake air volume. Furthermore, the 210B unit for calculating the estimated torque facilitates the approximation of the estimated torque to the target torque during the transition period by performing offset processing. Therefore, it can prevent the calculated estimated torque from failing to converge to the target torque due to the offset in the current intake air volume. [Fourth embodiment]

[0153] Next, a configuration example and an operating example of a unit for calculating the estimated torque according to a fourth embodiment are presented with reference to the Fig. described. Here, an example is described in which the calculation process of the estimated torque according to the present embodiment is applied to a hybrid vehicle.

[0154] Fig. Figure 20 is an explanatory diagram showing a configuration example of a 600 hybrid vehicle.

[0155] The hybrid vehicle 600 comprises an engine 601, a generator 602, a control unit 603, an engine 604, a power converter 605, a battery 606, a reduction gearbox 607, an axle 608, a tire 609 and a body 610 on which these devices are mounted.

[0156] The motor 601 transmits a driving force to the generator 602.

[0157] The generator 602 generates electricity through the driving force transmitted by the motor 601 and outputs alternating current to the power converter 605.

[0158] The control unit 603 controls the operation of the individual components of the engine 601, the generator 602, and the engine 604. The control unit 603 is configured by the same functional blocks as the ECU 102, which, with reference to Fig. The engine control device is described in Section 7 and is used as an example. Therefore, the control device 603 calculates the target torque with low response 207 and the target torque with high response 211 to obtain the estimated torque. Additionally, the control device 603 can achieve a desired engine torque in the transition state by adjusting the ignition timing correction amount and the number of fuel-deactivated cylinders to bring the estimated torque closer to the target torque with high response 211.

[0159] The power converter 605 converts the alternating voltage supplied by the generator 602 into a suitable power output and supplies it to the motor 604 to drive it. The power converter 605 also converts the alternating voltage supplied by the generator 602 so that the battery 606 can store the alternating voltage and charges the battery 606.

[0160] A drive shaft of the motor 604 is connected to the reduction gearbox 607, and the driving force of the motor 604 is transferred to the reduction gearbox 607.

[0161] The reduction gear 607 drives the axle 608, which is connected to the left and right tires 609, in a rotating manner. Therefore, the left and right tires 609 rotate in the direction of travel of the hybrid vehicle 600, and the hybrid vehicle 600 moves.

[0162] Fig. Figure 21 is a functional block diagram showing a configuration example of a unit 210C for calculating the estimated torque according to the fourth embodiment.

[0163] The unit 210C for calculating the estimated torque is in the Fig. The control unit 603 shown in Figure 20 is configured. The unit for calculating the estimated torque (unit 210C for calculating the estimated torque) contains a stored primary delay coefficient calculation unit 620, which replaces the primary delay coefficient calculation unit 301 of the estimated torque calculation unit 210 according to the first embodiment.

[0164] As in Fig. However, as shown in Figure 22, which is described later, the primary delay coefficient calculation unit 301 is configured to be integrated into the stored primary delay coefficient calculation unit 620.

[0165] The calculation unit 620 for the stored primary delay coefficient automatically calculates the primary delay coefficient 304 by inputting the target intake air quantity 303 calculated by the target intake air quantity calculation unit 300. At this point, the calculation unit 620 for the stored primary delay coefficient calculates the stored primary delay coefficient 304 (referred to as the "stored primary delay coefficient") and outputs it to the primary delay processing unit 302.

[0166] This describes why the stored primary delay coefficient calculation unit 620 automatically calculates the primary delay coefficient 304, which was calculated in the past and stored as a map.

[0167] If the hybrid vehicle 600 does not directly transmit the drive force of the motor 601 to the axle 608, the operating range of the motor torque of the motor 601 may be limited. Since the transient behavior of the motor 601 is limited in this case, the same transient behavior can be repeated. If the same transient behavior is repeated, the unit 210C does not need to perform the calculation of the estimated torque each time, as described in the first to third embodiments above.

[0168] Therefore, unit 210C reduces the computational load of calculating the estimated torque by, for example, using the primary delay coefficient 304, which is the result of a past calculation. When the same transient behavior is repeated, the processing of the primary delay coefficient 304, selected from the map containing the previously used primary delay coefficient, is added to unit 210's calculation of the estimated torque according to the first embodiment.

[0169] Fig. Figure 22 is a functional block diagram showing a configuration example of a stored primary delay coefficient calculation unit 620.

[0170] The stored primary delay coefficient calculation unit 620 comprises the primary delay coefficient calculation unit 301, a storage unit for past primary delay coefficients (storage unit for past primary delay coefficients 621), a unit for determining the use of past primary delay coefficients (determining unit for the use of past primary delay coefficients 622), and a unit for switching primary delay coefficients (switching unit for primary delay coefficients 623).

[0171] The primary delay coefficient calculation unit 301 automatically calculates a primary delay coefficient equivalent to the time constant τ, which is calculated based on the target intake air quantity 303 and the actual intake air quantity, as described in the first embodiment above. The primary delay coefficient calculated by the primary delay coefficient calculation unit 301 is output to the primary delay coefficient switching unit 623.

[0172] The memory unit 621 for past primary delay coefficients stores the primary delay coefficients used in the past. The primary delay coefficient is stored as a map for each driving scene of the hybrid vehicle 600. For example, the primary delay coefficient used in the driving scene with an engine speed of 2000 rpm and a torque of 100 N is stored in the memory unit 621 for past primary delay coefficients. When the driving scene of the hybrid vehicle 600 is then entered into the memory unit 621 for past primary delay coefficients, the primary delay coefficient read from the memory unit 621 for past primary delay coefficients is output to the switching unit 623 for primary delay coefficients, according to the driving scene.

[0173] The determination unit for the use of the primary delay coefficient in the past (determination unit 622 for the use of the primary delay coefficient in the past) determines one of the two primary delay coefficients that is used, where one primary delay coefficient is output by the calculation unit 301 for the primary delay coefficient and the other primary delay coefficient is stored in the storage unit 621 for the primary delay coefficient in the past and was used in a specific driving scene in the past, and outputs a determination result.For example, if the determination unit 622 for the use of the primary delay coefficient detects a repetition of the same transition behavior in the past, it performs a determination using the primary delay coefficient, which is the calculation result read from the storage unit 621 for the primary delay coefficient in the past. The determination unit 622 then outputs the determination result to the switching unit 623 for the primary delay coefficient.

[0174] If the behavior of the motor (motor 601) is limited in the transition state in which the current intake air quantity changes by a set value or more within a specified time, the primary delay coefficient switching unit 623 switches a primary delay coefficient to any of the primary delay coefficient read from the past primary delay coefficient storage unit (past primary delay coefficient storage unit 621) and the primary delay coefficient calculated by the primary delay coefficient calculation unit (primary delay coefficient calculation unit 301) based on the determination result of the determination unit for the use of the past primary delay coefficient (determination unit for the use of the past primary delay coefficient 622) and outputs the primary delay coefficient.Here, the switching unit for the primary delay coefficient (623) switches the primary delay coefficient based on the determination result entered by the determination unit for the use of the previous primary delay coefficient (622). The primary delay coefficient switched by the primary delay coefficient switching unit 623 is then output as the primary delay coefficient 304.

[0175] If the driving scenario, in which the engine speed is 2000 rpm and the torque is 100 N, occurs again as described above, the primary delay coefficient read from storage unit 621 for the previous primary delay coefficient is output as primary delay coefficient 304. The primary delay coefficient 304 output by the stored primary delay coefficient calculation unit 620 is entered into the Fig.The primary delay processing unit 302, as shown in Figure 21, is then entered. The primary delay processing unit (Primary Delay Processing Unit 302) can then perform the primary delay processing based on the target torque and the primary delay coefficient (Primary Delay Coefficient 304) selected by the primary delay coefficient switching unit (Primary Delay Coefficient Switching Unit 623), and can calculate the estimated torque of the motor (Motor 601) in the transition state.

[0176] It should be noted that if the determination unit 622 performs the determination using the primary delay coefficient read from the storage unit 621 for the primary delay coefficient in the past, the determination unit 622 instructs the calculation unit 301 for the primary delay coefficient to stop the calculation processing of the primary delay coefficient. This instruction allows the calculation unit 301 for the primary delay coefficient to stop processing the sequential calculation of the primary delay coefficient with respect to the input target intake air volume and the current intake air volume.

[0177] If the transient response of the motor 601 is limited, the estimated torque calculation unit 210C, according to the fourth embodiment described above, calculates the primary delay coefficient 304 from the card containing past calculation results and calculates the estimated torque in the transient state by performing the primary delay processing based on the target low-response torque 207 and the primary delay coefficient 304. Since the estimated torque calculation unit 210C does not perform the same calculation every time the same transient behavior is repeated, the computational load on the estimated torque calculation unit 210C can be reduced. [Modified example]

[0178] It should be noted that the current intake air volume used by the unit to calculate the estimated torque according to each of the embodiments described above is assumed to be the intake air volume in the cylinder calculated from the reading of airflow sensor 108. However, the reading of airflow sensor 108 or the intake air pressure value, which has a very high correlation with the generated engine torque, can also be used by the unit to calculate the estimated torque.

[0179] Furthermore, the calculation processing of the estimated torque, using the unit for calculating the estimated torque according to each of the embodiments described above, can be applied to engine torque control in traction control, automatic cruise control, automatic transmission, and the like. It can also be applied in combustion switching control (preventing a torque step generated at the time of combustion switching) when switching between stoichiometric and lean combustion.

[0180] By controlling the system according to each of the embodiments described above, it is possible to precisely control the torque generated by the motor in the transition state in order to reduce the vibration of the vehicle body and to suppress irregular vibrations of the vehicle body on which the motor is mounted.

[0181] Furthermore, the control system can be used according to any of the embodiments described above to control the torque generated by an engine other than the turbo engine.

[0182] Furthermore, the present invention is not limited to the embodiment described above and can assume various other application examples and modifications, as long as it does not deviate from the core of the present invention described in the claims.

[0183] The embodiment described above, for example, describes in detail and specifically the configurations of the device and the system in order to explain the present invention in an easily understandable manner, and is not necessarily limited to configurations that include all those described. Furthermore, it is possible to replace part of the configuration of the embodiment described here with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace part of the configuration of each embodiment with, from, or alongside another configuration.

[0184] Furthermore, control and information lines indicate what is deemed necessary for explanation, and not necessarily all control and information lines on the product. In practice, it can be assumed that almost all configurations are interconnected. List of reference signs 1 torque-based motor compatible with turbo engine 10 Motor 102 ECU 203 Target torque calculation unit 207 Target torque with low response time 210 Unit for calculating the estimated torque 211 Target torque with high response 300 Target intake air volume calculation unit 301 Calculation unit for the primary delay coefficient 302 Primary Delay Processing Unit 303 Target intake air volume 304 Primary delay coefficient

Claims

Engine control device (ECU 102), comprising: a target torque calculation unit (203) designed to calculate a target torque of an engine for which torque-based engine control is performed using an estimated torque; and a unit (210) for calculating the estimated torque, designed to calculate the estimated torque by performing primary delay processing on the target torque using a primary delay coefficient equivalent to a time constant calculated for each control cycle based on a change in an actual intake air quantity with respect to a target intake air quantity of the air drawn into the engine, wherein the unit (210) for calculating the estimated torque includes: a target intake air quantity calculation unit (300) designed toa target intake air quantity based on the target torque input by the target torque calculation unit (203) and an engine speed, and a primary delay coefficient calculation unit (301) designed to calculate the primary delay coefficient equivalent to the time constant calculated on the basis of the target intake air quantity and the actual intake air quantity, and a primary delay processing unit (302) designed to calculate the estimated torque by performing primary delay processing of the target torque based on the target torque and the primary delay coefficient, wherein the estimated torque calculation unit (210) further includes a divergence prevention processing unit (401) designed toto switch the primary delay coefficient calculated by unit (301) to a different value in order to prevent a divergence of the primary delay coefficient if the divergence occurs in the calculation of the primary delay coefficient performed by unit (301). Motor control device (ECU 102) according to claim 1, wherein the primary delay processing unit (302) is designed to calculate the estimated torque by performing primary delay processing on the target torque using the primary delay coefficient calculated in a transition state in which the target torque changes by a specified value or more within a specified time. Engine control device (ECU 102) according to claim 1, wherein the unit (301) for calculating the primary delay coefficient is designed to calculate the primary delay coefficient in a transition state in which the current intake air volume changes by a set value or more within a specified time. Engine control device (ECU 102) according to claim 1, wherein the primary delay processing unit (302) is designed to calculate the target torque as the estimated torque in a steady state in which the target intake air quantity and the actual intake air quantity are equal. Engine control device (ECU 102) according to claim 1, further comprising an ignition timing correction unit (215) designed to correct an ignition timing for the ignition of the fuel injected into a cylinder of the engine such that the estimated torque becomes the target torque. Engine control device (ECU 102) according to claim 1, further comprising a fuel cut-off control unit (216) designed to perform a fuel cut-off for one cylinder of the engine, so that the estimated torque becomes the target torque. Engine control device (ECU 102) according to claim 1, further comprising a fuel injection quantity control unit designed to correct a fuel injection quantity of a fuel injector that sends fuel to a cylinder of the engine such that the estimated torque becomes the target torque. Engine control device (ECU 102) according to claim 1, wherein the unit (210) for calculating the estimated torque further comprises: a primary delay coefficient limiting processing unit (501) configured to limit the primary delay coefficient input by the processing unit (401) for divergence prevention and to output the primary delay coefficient to the primary delay processing unit (302), and a second primary delay processing unit (404) configured to perform the primary delay processing of the target intake air quantity and to calculate an estimated intake air quantity of the engine based on the target intake air quantity and the primary delay coefficient limited by the primary delay coefficient limiting processing unit, and the unit (301) for calculating the primary delay coefficient is configured toto calculate the primary delay coefficient using a previous value of the estimated intake air volume instead of a previous value of the actual intake air volume. Engine control device (ECU 102) according to claim 8, wherein the unit (210) for calculating the estimated torque further comprises a constant delay processing unit (400) designed to perform filter processing with a delay coefficient as a constant to reduce the vibration of the current intake air volume, and the unit (301) for calculating the primary delay coefficient is designed to calculate the primary delay coefficient based on the target intake air volume, the current intake air volume on which the filter processing is performed, and the estimated intake air volume input from the second primary delay processing unit (404). Engine control device (ECU 102) according to claim 1, wherein the unit (210) for calculating the estimated torque further comprises: a constant delay processing unit (400) designed to perform filter processing with a delay coefficient as a constant to reduce the vibration of the current intake air volume, and an offset processing unit (500) designed to perform offset processing on the current intake air volume on which the filter processing is performed by the constant delay processing unit (400) using an offset value that is maintained in a steady state in which the target intake air volume and the current intake air volume are equal, and the primary delay coefficient calculation unit (301) designed to calculate the primary delay coefficient based on the target intake air volume.to calculate the current intake air volume on which the offset processing is performed and an estimated intake air volume of the engine. Engine control device (ECU 102) according to claim 10, wherein the unit (210) for calculating the estimated torque further comprises: a second primary delay coefficient limiting processing unit (501) configured to limit the primary delay coefficient by switching a lower limit of the primary delay coefficient, the divergence of which is prevented by the processing unit (401) for divergence prevention, to a different value, and a second primary delay processing unit (404) configured to calculate the estimated intake air quantity of the engine by performing the primary delay processing of the target intake air quantity and outputting the estimated intake air quantity to the primary delay coefficient calculation unit, based on the target intake air quantity and the primary delay coefficient limited by the second primary delay coefficient limiting processing unit (501).Motor control device (ECU 102) according to claim 1, wherein the unit (210) for calculating the estimated torque comprises: a storage unit (621) for past primary delay coefficients, which is designed to store a primary delay coefficient used in the past; a determination unit (622) for using a past primary delay coefficient, which is designed to determine one of the two primary delay coefficients that is used, wherein one primary delay coefficient is output by the primary delay coefficient calculation unit and the other primary delay coefficient is stored in the storage unit (621) for the past primary delay coefficient and was used in a specific control scene in the past, and outputs a determination result; and a primary delay coefficient switching unit (623), which is designed toto switch a primary delay coefficient to any of the primary delay coefficients read from the memory unit (621) for past primary delay coefficients and the primary delay coefficient calculated by the primary delay calculation unit, and to output the primary delay coefficient based on the determination result when engine behavior is limited in a transition state in which the current intake air quantity changes by a set value or more within a specified time, and the primary delay processing unit (302) is designed to perform primary delay processing based on the target torque and the primary delay coefficient selected by the primary delay coefficient switching unit (623), and to calculate the estimated torque of the engine in the transition state.Method for engine control, comprising: calculating a target torque of an engine for which torque-based engine control is performed using an estimated torque; calculating a time constant for each control cycle based on a change in a current intake air quantity with respect to a target intake air quantity of the air drawn into the engine; calculating a primary delay coefficient equivalent to the time constant; and calculating the estimated torque by performing primary delay processing on the target torque using the primary delay coefficient; calculating a target intake air quantity based on the target torque input by the target torque calculation unit (203) and an engine speed; and calculating the primary delay coefficient equivalent to the time constant calculated on the basis of the target intake air quantity and the current intake air quantity.Calculating the estimated torque by performing primary delay processing of the target torque based on the target torque and the primary delay coefficient, wherein the calculation of the estimated torque further includes divergence prevention, which switches the calculated primary delay coefficient to a different value to prevent a divergence of the primary delay coefficient if the divergence occurs during the calculation of the primary delay coefficient.

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