CN104948322A - Control device of internal combustion engine - Google Patents

Abstract

The present invention is a control device for an internal combustion engine. In the existing structure, when the phase or lift of the intake and exhaust valves is controlled by the exhaust gas recirculation or the variable valve mechanism, the calculation accuracy of the amount of air sucked into the barrel deteriorates, resulting in a change in the air-fuel ratio. Deterioration of exhaust gas caused by fluctuations, knocking caused by torque fluctuations, misfires, and over-advance angles of ignition timing, or combustion instability caused by over-retarded angles. An air flow sensor is provided upstream of the throttle valve and a pressure sensor is provided downstream of the throttle valve, and the passage flow rate of the throttle valve is calculated based on the pressure sensor, and the flow rate downstream of the throttle valve is calculated based on the calculated flow rate of the throttle valve. Pressure, based on the calculated downstream pressure of the throttle valve, the unit for calculating the intake air volume of the cylinder; based on the throttle valve passing flow detected by the air flow sensor, the unit for correcting the throttle valve passing flow calculated based on the pressure sensor.

Description

Control devices for internal combustion engines

technical field

The invention relates to a control device for an internal combustion engine.

Background technique

Conventionally, a control device for an internal combustion engine has been realized that uses an airflow sensor incorporated in the intake passage of the internal combustion engine to actually measure the amount of air sucked into the internal combustion engine, and controls the amount of fuel injection based on the measured amount of intake air. In addition, a control device for an internal combustion engine including an exhaust gas recirculation control device that recirculates a part of exhaust gas discharged to the exhaust passage to the intake passage and controls the amount of exhaust gas recirculation is realized. Furthermore, a control device for an internal combustion engine has been realized that includes a variable valve mechanism for the intake and exhaust valves and controls the phase or lift of the intake and exhaust valves.

Patent Document 1 discloses that the amount of intake air obtained by compensating for the detection response delay of the airflow sensor and the amount of change in the intake air pressure detected by the intake air pressure sensor downstream of the throttle valve are used to calculate the amount of air sucked into the air cylinder. The unit for the first air volume calculates the first air volume sucked into the air cylinder based on the intake air volume obtained by not compensating for the detection response delay of the airflow sensor and the change in the intake air pressure detected by the intake air pressure sensor on the downstream side of the throttle valve. The unit of the two air volumes is a control device for an internal combustion engine that switches between the first air volume and the second air volume according to the operating state of the internal combustion engine, and performs control such as fuel injection control. According to this technique, since the detection response delay of the air flow sensor is compensated, the control accuracy at the time of transition can be improved.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2009-138590

Contents of the invention

The problem to be solved by the invention

However, in the technique of Patent Document 1, a change in the intake pressure on the downstream side of the throttle valve due to a change in the exhaust gas recirculation amount is not considered in the calculation of the amount of air sucked into the cylinder, so it is considered The calculation accuracy of the air volume sucked into the air cylinder deteriorates. Therefore, there is a problem that it cannot be applied to an internal combustion engine equipped with an exhaust gas recirculation control device. In addition, since the change in the amount of air sucked into the air cylinder is calculated based on the change in the intake pressure downstream of the throttle valve caused by the change in the phase or lift of the intake and exhaust valve, it is impossible to capture the change of the intake and exhaust valve. The air volume in the air tank changes when the phase or the lift amount changes sharply, and there is a problem that the control accuracy deteriorates.

The present invention is the result of earnest research in view of the above-mentioned problems, and its object is to accurately determine the flow rate sensor and pressure sensor even in an exhaust gas recirculation control device or an internal combustion engine with a variable valve mechanism for intake and exhaust valves. The amount of air being flowed into the cylinder is well calculated and used to improve the accuracy of the engine control.

technical means to solve problems

In order to solve the above-mentioned problems, the control device of the present invention is a control device for an internal combustion engine provided with an air flow sensor upstream of the throttle valve and a pressure sensor downstream of the throttle valve, the control device having: a calculation unit based on the pressure sensor Calculate the passing flow rate of the throttle valve, calculate the pressure downstream of the throttle valve based on the calculated throttle valve passing flow rate, and calculate the suction flow into the air cylinder based on the calculated throttle valve downstream pressure an air volume; and a correcting unit for correcting a throttle valve passing flow rate calculated based on the pressure sensor based on a throttle valve passing flow rate detected by the air flow sensor, the correcting unit correcting a throttle valve flow rate characteristic value and a sensor characteristic value, The difference between the throttle flow rate estimated based on the pressure sensor and the throttle flow rate detected by the air flow sensor is made to be equal to or smaller than a predetermined value.

The effect of the invention

According to the present invention, the passing flow rate of the throttle valve is calculated based on the pressure sensor, the pressure downstream of the throttle valve is calculated based on the calculated throttle valve passing flow rate, and the pressure sucked into the air cylinder is calculated based on the calculated throttle valve downstream pressure. air volume. The influence of the change in the intake pressure on the downstream side of the throttle valve due to the change in the exhaust gas recirculation amount on the throttle valve passing flow rate can be properly considered, so that the deterioration of the control accuracy of the internal combustion engine can be prevented. In addition, since the change in the flow rate through the throttle valve when the phase of the intake and exhaust valves or the lift suddenly changes can be appropriately taken into consideration, it is possible to prevent deterioration of the control accuracy of the internal combustion engine. In addition, since the response characteristics of the airflow sensor and the flow characteristics of the throttle valve, which change due to the influence of deterioration over time, are sequentially corrected based on the airflow sensor and the pressure sensor, it is possible to accurately calculate the amount of air sucked into the air cylinder, And it is possible to improve the control accuracy of the internal combustion engine.

Description of drawings

FIG. 1 is a diagram illustrating a system configuration according to Embodiment 1 of the present invention.

FIG. 2 is a diagram illustrating a method of EGR control for rotational speed and load.

Fig. 3 illustrates how to set the throttle valve opening, EGR valve opening, and intake and exhaust valve phases with respect to the change in the load direction (A→B) obtained from a constant rotational speed in Fig. A graph of changes in suction pressure and EGR rate.

4 is a diagram illustrating a flow of a method of controlling the internal combustion engine using the amount of air flowing into the cylinder calculated based on the detection value of the airflow sensor.

5 is a diagram illustrating a flow of a method of controlling the internal combustion engine using the amount of air flowing into the air cylinder calculated based on the detection value of the pressure sensor.

6 is a diagram illustrating a flow of a method of controlling an internal combustion engine using a first air volume calculated based on a detected value of an air flow sensor and a second air volume calculated based on a detected value of a pressure sensor.

FIG. 7 is a diagram illustrating a flow of a method of controlling an internal combustion engine executed in the present invention.

FIG. 8 is a diagram illustrating a model of flow in an intake pipe required for metering air and EGR.

FIG. 9 is a diagram illustrating a block diagram of controlling fuel injection and ignition timing based on an air flow sensor and a pressure sensor.

FIG. 10 is a diagram illustrating a block diagram of calculating the throttle passing air amount based on the detection value of the pressure sensor, and correcting the calculated throttle passing air amount by the air flow sensor.

FIG. 11 is a diagram illustrating a difference between a detected value or a calculated value of a throttle valve passing flow rate and a true value under an acceleration condition in which the throttle valve opening degree is increased from a low load state depending on the air metering method.

FIG. 12 is a diagram illustrating a difference between a detected value or a calculated value of the intake pressure and a true value under an acceleration condition in which the throttle valve opening degree is increased from a low load state depending on the air metering method.

13 is a diagram illustrating the difference between the detected value or calculated value and the true value of the amount of air flowing into the air cylinder under the acceleration condition of increasing the throttle valve opening from the low load state due to the difference in the air metering method, and the difference due to the difference. A plot of the difference in behavior of the exhaust air-fuel ratio is produced.

FIG. 14 is a graph explaining differences in detected values or calculated values of the throttle valve passing flow rate under deceleration conditions in which the throttle valve opening degree is reduced from a high load state due to differences in air metering methods.

FIG. 15 is a diagram illustrating a difference between a detected value or a calculated value of the intake pressure and a true value under a deceleration condition in which the throttle valve opening is decreased from a high load state depending on the air metering method.

16 is a diagram illustrating the difference between the detected value or the calculated value and the true value of the amount of air flowing into the air cylinder under the deceleration condition of reducing the throttle valve opening from the high load state due to the difference in the air metering method, and the difference due to the difference. A plot of the difference in behavior of the exhaust air-fuel ratio is produced.

Fig. 17 is a diagram illustrating the calculation or detection of the throttle valve flow rate, suction pressure, and air cylinder inflow air volume by the air metering method ③ of the present invention, and correcting the throttle valve caused by the fouling of the throttle valve based on the air flow sensor. The graph of the difference from the true value for the case of the change of the flow characteristic of , and the case of no correction.

Fig. 18 is a diagram illustrating a system according to Embodiment 2 including an exhaust gas recirculation control device for controlling an exhaust gas recirculation amount from a part of the exhaust gas discharged to the exhaust passage downstream from the turbine to the intake passage upstream of the compressor; Structure diagram.

FIG. 19 is a diagram illustrating a method of EGR control of the rotation speed and load in the system of Embodiment 2. FIG.

20 is a diagram illustrating a block diagram for controlling the amount of intake air in a cylinder required for fuel injection and ignition timing based on an airflow sensor and a pressure sensor in the system according to Embodiment 2. FIG.

21 is a diagram illustrating a block diagram of calculating the negative pressure valve passing air amount based on the detection value of the pressure sensor and correcting the calculated negative pressure valve passing air amount by the air flow sensor in the system according to the second embodiment.

Detailed ways

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a diagram illustrating a system configuration according to Embodiment 1 of the present invention. The system of this embodiment includes an internal combustion engine 1 . An intake flow path and an exhaust flow path communicate with the internal combustion engine 1 . An airflow sensor 2 and an intake air temperature sensor incorporated in the airflow sensor 2 are incorporated in the airflow path. Downstream of the air flow sensor 2, a throttle valve 3 for narrowing the intake flow path and controlling the amount of intake air flowing into the cylinder is provided. The throttle valve 3 is an electronically controlled throttle valve capable of controlling the opening of the valve independently of the throttle pedal. An intake manifold 4 communicates downstream of the throttle valve 3 . An intake pressure sensor 5 is incorporated in the intake manifold 4 . Downstream of the intake manifold 4, a flow enhancement valve 6 for enhancing turbulence of the flow in the cylinder by generating a bias flow in the intake air is arranged. A fuel injection valve 7 for directly injecting fuel into the cylinder is arranged in the cylinder. The internal combustion engine 1 includes variable valve mechanisms for continuously changing the phases of opening and closing of the intake valves 8 and exhaust valves 10 . In the variable valve mechanism, sensors 9 and 11 for detecting the opening and closing phases of the valves are incorporated in the intake valve 8 and the exhaust valve 10, respectively. A spark plug 12 for igniting a combustible air-fuel mixture by an electric spark is assembled in the head of the cylinder by exposing the electrode part in the cylinder. Furthermore, a knock sensor 13 for detecting the occurrence of knocking is incorporated in the cylinder block. A crank angle sensor 14 is incorporated into the crankshaft. Based on the signal output from the crank angle sensor 14, the rotation speed of the internal combustion engine 1 can be detected. An air-fuel ratio sensor 15 is incorporated in the exhaust flow path, and feedback control is performed based on the detection result of the air-fuel ratio sensor so that the fuel injection amount supplied from the fuel injection valve 7 becomes a target air-fuel ratio. Downstream of the air-fuel ratio sensor 15, an exhaust purification catalyst 16 is provided, and harmful exhaust gas components such as carbon monoxide, nitrogen oxides, and unburned hydrocarbons are purified by catalytic reactions. Downstream of the exhaust purification catalyst 16, an oxygen sensor 17 for detecting the presence or absence of oxygen in the exhaust gas passing through the exhaust purification catalyst is incorporated. An EGR pipe 18 that divides exhaust gas downstream of the exhaust purification catalyst 16 and returns the exhaust gas to the intake manifold 4 communicates. An EGR cooling device 19 for cooling EGR is provided in the EGR pipe 18 . An EGR valve 22 for controlling the EGR flow rate is provided downstream of the EGR cooling device 19 . A temperature sensor 20 for detecting an EGR temperature at an upstream portion of the EGR valve 22 and a pressure sensor 21 for detecting a pressure at an upstream portion of the EGR valve 22 are incorporated. The system of this embodiment includes an ECU (Electronic Control Unit, electronic control unit) 23 as shown in FIG. 1 . The above-mentioned various sensors and various actuators are connected to the ECU 23 . Actuators such as the throttle valve 3 , the fuel injection valve 7 , the intake and exhaust valves 8 and 10 with variable mechanisms, and the EGR valve 22 are controlled by the ECU 23 . In addition, based on signals input from the above-mentioned various sensors, the operating state of the internal combustion engine 1 is detected, and the spark plug 12 ignites at a timing determined by the ECU 23 according to the operating state.

FIG. 2 is a diagram illustrating a method of EGR control of the rotational speed and load of the internal combustion engine 1 . Under low rotational speed and low load conditions, the pumping loss is reduced by introducing internal EGR through the intake and exhaust phase variable valve. The frequency of knocking and the exhaust gas temperature are reduced by introducing external EGR cooled by the EGR cooling device under load conditions above the medium load. Since it is not necessary to perform fuel increase control aimed at the effect of lowering the exhaust gas temperature, fuel consumption can be reduced.

Fig. 3 illustrates how to set the throttle valve opening, EGR valve opening, and intake and exhaust valve phases with respect to the change in the load direction (A→B) obtained from a constant rotational speed in Fig. A graph of changes in suction pressure and EGR rate. In the low load region, the effective compression ratio can be lowered by retarding the phase of the intake valve, and the pump loss can be reduced by reducing the suction negative pressure into the cylinder. In addition, at the same time, the exhaust closing angle is retarded to increase the internal EGR, thereby reducing the pump loss. On the other hand, under the condition of above medium load, the exhaust closing angle is advanced to near the top dead center, in order to reduce the internal EGR and maintain the total EGR rate, increase the EGR valve opening, and increase the external EGR. External EGR recirculates the exhaust gas cooled by the EGR cooling device, thereby reducing fuel consumption by knocking and lowering the exhaust gas temperature.

4 is a diagram illustrating a flow of a method of controlling the internal combustion engine using the amount of air flowing into the cylinder calculated based on the detection value of the air flow sensor. In the method, in step 401 , an air flow sensor is used to detect the flow of air through a throttle valve. In step 402 , based on the flow rate of air passing through the throttle valve and the flow rate of air sucked into the cylinder, the balance of the amount of air entering and exiting the intake pipe is calculated, and the temperature and pressure in the intake pipe are calculated. In step 403, the flow rate of air sucked into the air cylinder is calculated based on the temperature and pressure in the suction pipe. In step 404, fuel injection is controlled based on the air flow drawn into the cylinder. In step 405, the ignition timing is controlled based on the air flow drawn into the cylinder. According to this method, fuel injection or ignition timing is controlled based on the actual measured value of the air flow sensor, and therefore, robust control can be realized with respect to state changes of the internal combustion engine. On the other hand, since there is a detection delay in the air flow sensor, unless delay compensation is performed on the detection result, there is a problem that the control accuracy at the time of transition of the internal combustion engine deteriorates.

5 is a diagram illustrating a flow of a method of controlling the internal combustion engine using the amount of air flowing into the air cylinder calculated based on the detection value of the pressure sensor. In the method, in step 501 , an intake pressure is detected using a pressure sensor provided downstream of a throttle valve. In step 502, the flow of air drawn into the air cartridge is controlled based on the inspiratory pressure. In step 503, fuel injection is controlled based on the air flow drawn into the cylinder. In step 504, the ignition timing is controlled based on the air flow drawn into the cylinder. According to this method, since the pressure sensor has higher responsiveness than the airflow sensor, even if delay compensation is not performed on the detection result, deterioration of the control accuracy at the transition of the internal combustion engine is not observed. On the other hand, since the air volume flowing into the cylinder is converted from the pressure of the intake pipe, there is a problem that control accuracy deteriorates when the state of the internal combustion engine changes.

6 is a diagram illustrating a flow of a method of controlling an internal combustion engine using a first air volume calculated based on a detected value of an air flow sensor and a second air volume calculated based on a detected value of a pressure sensor. In this method, in step 601, a determination of stability of the internal combustion engine is performed. If it is determined to be a steady state, then in step 602 , an air flow sensor is used to detect the flow of air passing through the throttle valve. In step 603, based on the flow rate of air passing through the throttle valve and the flow rate of air sucked into the air cylinder, the balance of the amount of air entering and exiting the intake pipe is calculated, and the temperature and pressure in the intake pipe are calculated. In step 604, the first air flow rate sucked into the air cylinder is calculated based on the temperature and pressure in the suction pipe. On the other hand, if it is determined to be a transient state, then in step 605, the intake pressure is detected using a pressure sensor provided downstream of the throttle valve. In step 606, a second air flow rate drawn into the air cylinder is calculated based on the suction pressure. In step 607, fuel injection is controlled based on the air flow being drawn into the cylinder. In step 608, the ignition timing is controlled based on the air flow drawn into the cylinder. According to this method, the fuel injection or the ignition timing is controlled based on the actual measurement value of the airflow sensor at a steady state, and therefore robust control can be realized with respect to the state of the internal combustion engine. In addition, since the flow rate of the air sucked into the air cylinder is calculated based on the intake pressure detected by the highly responsive pressure sensor at the time of transition, it is possible to prevent deterioration of accuracy at the time of transition. However, since the air flow rate calculated by different methods in the steady state and the transient state is switched according to the operating state, there is a problem that a step difference occurs at the time of switching, deteriorating the control accuracy.

FIG. 7 is a diagram illustrating a flow of a method of controlling an internal combustion engine executed in the present invention. In the method, in step 701 , the suction pressure is detected using a pressure sensor provided downstream of the throttle valve. In step 702, the throttle valve through flow rate is calculated based on the detected intake pressure. In step 703, the air flow sensor is used to detect the flow rate through the throttle valve. In step 704, the throttle valve flow characteristic and the air flow sensor sensor characteristic are sequentially determined based on the throttle valve passing flow calculated based on the intake pressure detection value and the throttle passing flow detected using the air flow sensor. Based on the determined result, the throttle passing flow calculated based on the intake pressure detection value and the throttle passing flow detected using the air flow sensor are sequentially corrected. Here, the flow characteristic of the throttle valve is the flow coefficient of the throttle valve. The flow coefficient of the throttle valve is a function or a table using the rotational speed of the internal combustion engine and the valve opening as parameters, and the flow coefficient is determined for each level of the rotational speed of the internal combustion engine and the valve opening, and the flow coefficient is updated using the determination result. function or form. In addition, the so-called sensor characteristic of the airflow sensor is a time constant. The time constant is a function or table that takes the flow rate as a parameter, determines the time constant for each flow rate, and uses the determined result to update the function or table of the time constant. In step 705, based on the sequentially corrected throttle valve passage flow rate and the air flow rate flowing into the cylinder, budget calculation is performed to calculate the pressure and temperature in the intake pipe. In step 706, the flow rate of air flowing into the air cylinder is calculated based on the calculated pressure and temperature in the intake pipe. In step 707, fuel injection is controlled based on the air flow drawn into the cylinder. In step 708, the ignition timing is controlled based on the air flow drawn into the cylinder. According to this method, the responsiveness of calculating the air cylinder inflow air amount at the time of transition is limited to the responsiveness of the pressure sensor, and therefore, the air cylinder inflow air amount can be calculated without delay at the time of transition. In addition, even if the flow rate characteristics of the throttle valve change due to the adhesion of deposits, etc., the flow rate characteristics of the throttle valve can be corrected using the intake air flow rate directly detected by the air flow sensor. The robustness of precision is high. In addition, regardless of transition or stabilization, since changes in the flow rate characteristics of the throttle valve or the sensor characteristics of the airflow sensor are sequentially corrected, there is no step difference when switching between transition and stabilization. The above-mentioned correction can be performed during operation of exhaust gas recirculation or a variable valve, and can be applied to an internal combustion engine equipped with an exhaust gas recirculation device or a variable valve mechanism. Therefore, even during a transition of an internal combustion engine equipped with an exhaust gas recirculation device or a variable valve mechanism, control of fuel injection and ignition timing can be executed with high precision. Here, an algorithm for determining the throttle valve flow characteristic (flow coefficient) and the air flow sensor characteristic (time constant) will be described. The flow rate of the throttle valve can be obtained from Equation (1).

$\frac{{\mathrm{dm}}_{\mathrm{the\; th}}}{\mathrm{dt}}={\mathrm{\μ}}_{\mathrm{the\; th}}{A}_{\mathrm{the\; th}}{p}_{\mathrm{atm}}\sqrt{\frac{2}{R{T}_{\mathrm{atm}}}}\·\mathrm{\Ψ}(p_{\mathrm{atm}},p_{\mathrm{in}})$ …Formula 1)

$\begin{array}{cc}\mathrm{<span\; class="notranslate">\; \&Psi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; atm</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\sqrt{\frac{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}& \frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; atm</span>}}}<span\; class="notranslate">\; <</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}$

$\mathrm{<span\; class="notranslate">\; \&Psi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; atm</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \{</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; atm</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; atm</span>}}}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}<span\; class="notranslate">\; \}</span>}\frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; atm</span>}}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}$

Here, μ _th is the flow coefficient of the throttle valve, A _th is the opening area of the throttle valve, κ is the specific heat ratio, and R is the gas constant. On the other hand, assuming that the delay behavior of the airflow sensor can be approximated by a primary delay element, the true throttle valve flow rate can be calculated by Equation (2) using the primary progression element with the detection value of the airflow sensor as an input.

$\frac{{\mathrm{dm}}_{\mathrm{the\; th}}}{\mathrm{dt}}=(1+\frac{{\mathrm{\&tau;}}_{\mathrm{afs}}}{\mathrm{\&Delta;t}})\frac{{\mathrm{dm}}_{\mathrm{afs}}\left(k\right)}{\mathrm{dt}}-\frac{{\mathrm{\&tau;}}_{\mathrm{afs}}}{\mathrm{\&Delta;t}}\frac{{\mathrm{dm}}_{\mathrm{afs}}(k-1)}{\mathrm{dt}}$ ...Formula (2)

Here, τ _afs is the time constant of the airflow sensor, and Δt is the sampling time. If equation (1) and equation (2) are equal, the following relationship is obtained.

$\frac{{\mathrm{dm}}_{\mathrm{afs}}\left(k\right)}{\mathrm{dt}}=\frac{1}{1+{\mathrm{\&tau;}}_{\mathrm{afs}}/\mathrm{\&Delta;t}}[{\mathrm{\&mu;}}_{\mathrm{the\; th}}{A}_{\mathrm{the\; th}}{P}_{\mathrm{atm}}\sqrt{\frac{2}{{\mathrm{RT}}_{\mathrm{atm}}}}\&Center\; Dot;\mathrm{\&Psi;}(p_{\mathrm{atm}},p_{\mathrm{im}})+\frac{{\mathrm{\&tau;}}_{\mathrm{afs}}}{\mathrm{\&Delta;t}}\frac{{\mathrm{dm}}_{\mathrm{afs}}(k-1)}{\mathrm{dt}}]$ ...Formula (3)

Here, k is the number of steps. When formula (3) is sorted out, simultaneous equations as shown in formula (4) are obtained.

x(k)＝φ(k) ^T θ(k) ...Formula (4)

$\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; dm</span>}}_{\mathrm{<span\; class="notranslate">\; afs</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\begin{array}{}\end{array}\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; atm</span>}}\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; RT</span>}}_{\mathrm{<span\; class="notranslate">\; atm</span>}}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&Psi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; atm</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; im</span>}}<span\; class="notranslate">\; )</span>\\ \frac{{\mathrm{<span\; class="notranslate">\; dm</span>}}_{\mathrm{<span\; class="notranslate">\; afs</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; dt</span>}}\end{array}\right]<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\begin{array}{}\left[\begin{array}{c}\frac{{\mathrm{<span\; class="notranslate">\; \&mu;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; afs</span>}}}\\ \frac{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; afs</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; afs</span>}}}\end{array}\right]\end{array}$

Based on formula (4), the throttle valve flow coefficient and the time constant of the airflow sensor are determined using the successive least squares algorithm that takes into account the forgetting elements.

x(k)＝ ^φT (k)·θ(k)+ε(k) ...Formula (5)

$\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span>}$ $\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>$

$\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>$

Here, λ is a forgetting factor, and is usually set between 0.97 and 0.995. By repeatedly calculating the formula (5), θ(k) is sequentially updated, and the flow coefficient μ _th of the throttle valve and the time constant τ _afs of the airflow sensor can be obtained from θ(k). In the present invention, the throttle valve flow coefficient is selected among sequentially determined parameters, but the present invention is not limited thereto, and the same effect can be achieved even if the pressure loss coefficient is set as the throttle valve flow coefficient. In addition, the primary delay is assumed in the approximation of the detection delay of the air flow sensor, but a dead time or a function of the secondary delay system or more may be set.

FIG. 8 is a diagram illustrating a model of flow in an intake pipe required for metering air and EGR. The air flow rate of the throttle valve can be directly detected by the air flow sensor 2 installed upstream of the throttle valve. On the other hand, based on the intake air pressure detected by the pressure sensor 5 installed downstream of the throttle valve, the intake air temperature detected by the temperature sensor built in the air flow sensor, and the throttle valve opening degree, the above formula (1) can be used To calculate the throttle valve flow. An EGR temperature sensor for detecting the temperature of the EGR and an EGR pressure sensor for detecting the pressure of the EGR are installed upstream of the EGR valve. Based on the upstream pressure and upstream temperature of the EGR valve, the intake pressure, and the opening degree of the EGR valve, the flow rate of the exhaust gas passing through the EGR valve can be calculated from Equation (6).

$\frac{{\mathrm{dm}}_{\mathrm{egrv}}}{\mathrm{dt}}={\mathrm{\&mu;}}_{\mathrm{egrv}}{A}_{\mathrm{egrv}}{p}_{\mathrm{up}}\sqrt{\frac{2}{R{T}_{\mathrm{up}}}}\&CenterDot;\mathrm{\&Psi;}(p_{\mathrm{up}},p_{\mathrm{in}})$ ...Formula (6)

$\begin{array}{cc}\mathrm{<span\; class="notranslate">\; \&Psi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; up</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\sqrt{\frac{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}& \frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; up</span>}}}<span\; class="notranslate">\; <</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}$

$\mathrm{<span\; class="notranslate">\; \&Psi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; up</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \{</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; up</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; up</span>}}}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}<span\; class="notranslate">\; \}</span>}\frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; up</span>}}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}$

Here, μ _egrv is the flow coefficient of the EGR valve, and A _egrv is the opening area of the EGR valve. The flow rate of air sucked into the air cylinder can be calculated by Equation (7) using the state quantity of the suction pipe.

$\frac{{\mathrm{dm}}_{\mathrm{cyl}}}{\mathrm{dt}}=\frac{p_{\mathrm{in}}}{{\mathrm{RT}}_{\mathrm{in}}}{\mathrm{no}}_{\mathrm{cyl}}{v}_{\mathrm{the\; s}}{\mathrm{\&eta;}}_{\mathrm{in}}\frac{N_e}{120}$ ...Formula (7)

Here, _{n cyl} is the number of cylinders of the internal combustion engine, V _s is the stroke volume, η _in is the intake efficiency, and Ne is the rotational speed of the internal combustion engine. η _in is a function or table of rotational speed of the internal combustion engine, load, and intake and exhaust valve phases. Using these flow rates, the calculation of the budget in the intake pipe is carried out by Equation (8).

$\frac{{\mathrm{<span\; class="notranslate">\; dm</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; dm</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; dm</span>}}_{\mathrm{<span\; class="notranslate">\; egrv</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; dm</span>}}_{\mathrm{<span\; class="notranslate">\; cyl</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}$

$\frac{{\mathrm{de}}_{\mathrm{in}}{m}_{\mathrm{in}}}{\mathrm{dt}}=h_{\mathrm{atm}}\frac{{\mathrm{dm}}_{\mathrm{the\; th}}}{\mathrm{dt}}+h_{\mathrm{up}}\frac{{\mathrm{dm}}_{\mathrm{egrv}}}{\mathrm{dt}}-h_{\mathrm{in}}\frac{{\mathrm{dm}}_{\mathrm{cyl}}}{\mathrm{dt}}$ ... (Equation 8)

$\frac{{\mathrm{<span\; class="notranslate">\; dm</span>}}_{\mathrm{<span\; class="notranslate">\; egr</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; dm</span>}}_{\mathrm{<span\; class="notranslate">\; egrv</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}\frac{{\mathrm{<span\; class="notranslate">\; dm</span>}}_{\mathrm{<span\; class="notranslate">\; cyl</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}$

$<span\; class="notranslate">\; \&DoubleRightArrow;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; im</span>}}}{\mathrm{<span\; class="notranslate">\; RT</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; egr</span>}}}{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}}$

Here, h is enthalpy, e is total energy, and r is EGR rate. In addition, in the system of the present embodiment, the sensor detects the upstream temperature and upstream pressure of the EGR valve, but the present invention is not limited to this, and the EGR pressure and the EGR temperature are recorded in the rotational speed and the load. The same effect can also be achieved on the map and obtained by map operations. In addition, in the system of the present embodiment, the sensor detects the upstream temperature and upstream pressure of the EGR valve and calculates the EGR flow rate. However, the present invention is not limited thereto. The same effect can also be achieved by subtracting the EGR rate calculated based on the air partial pressure of the downstream part of the throttle valve through the flow calculation of the throttle valve from the pressure (total pressure) detected by the pressure sensor of the throttle valve.

9 is a diagram illustrating a block diagram of controlling fuel injection and ignition timing based on an air flow sensor and a pressure sensor. According to this method, in block 901, the throttle is calculated based on the air flow sensor, the throttle valve opening, the atmospheric pressure, the atmospheric temperature detected by the temperature sensor built into the air flow sensor, and the suction pressure detected by the pressure sensor downstream of the throttle valve. flow valve through flow. In block 902 , the EGR valve passing flow rate is calculated based on the intake pressure, the EGR valve opening degree, the EGR valve upstream temperature, and the EGR valve upstream pressure. In block 903 , the total gas budget in the intake pipe is calculated based on the flow rate through the throttle valve, the flow rate through the EGR valve, the state quantities in the intake pipe (pressure, temperature, EGR rate), and the amount of inhaled air in the cylinder. In block 904 , EGR budget calculation in the intake pipe is performed based on the flow rate of the EGR valve, the state quantities in the intake pipe (pressure, temperature, EGR rate), and the amount of intake air in the cylinder. In block 905 , state quantities (pressure, temperature, EGR rate) in the intake pipe are calculated based on the air amount in the intake pipe, the EGR amount, the ambient temperature, and the temperature upstream of the EGR valve. In block 906 , the amount of air flowing into the cylinder is calculated based on the rotation speed of the internal combustion engine, the phase of the intake and exhaust valves, and the state quantities (pressure, temperature, and EGR rate) in the intake pipe. In block 907, the target air-fuel ratio is calculated based on the rotational speed of the internal combustion engine and the amount of air flowing into the cylinder. In block 908 , the injection pulse width is calculated based on the rotational speed of the internal combustion engine, the amount of air flowing into the cylinder, and the target air-fuel ratio. In block 908 , the ignition timing is calculated based on the rotational speed of the internal combustion engine, the amount of air flowing into the cylinder, and the state quantities (pressure, temperature, and EGR rate) in the intake pipe. With such a configuration, even during a transition of an internal combustion engine equipped with an exhaust gas recirculation device or a variable valve mechanism, control of fuel injection and ignition timing can be executed with high precision.

10 is a diagram illustrating a block diagram of calculating the throttle passing air amount based on the detection value of the pressure sensor, and correcting the calculated throttle passing air amount by the air flow sensor. According to this method, in block 1001 , the throttle flow is calculated based on the throttle opening, throttle upstream pressure, throttle upstream temperature, and throttle downstream pressure. In block 1002, the throttle flow rate characteristic is determined using the calculated throttle flow rate and the corrected air flow sensor detection value corrected in consideration of sensor characteristics. Here, the parameter that should be determined is the flow coefficient of the throttle valve. The flow coefficient is a function or a table using the rotation speed of the internal combustion engine and the valve opening as parameters, the flow coefficient is determined for each level of the rotation speed of the internal combustion engine and the valve opening, and the function or table of the flow coefficient is updated based on the determination result. In block 1003, the calculated value of the throttle flow rate is corrected based on the determination result of the throttle flow rate after the calculation and the throttle flow characteristic. In block 1004, the sensor characteristic of the airflow sensor is determined based on the detected value of the airflow sensor and the corrected throttle flow calculation value corrected in consideration of the throttle flow characteristic. Here, the parameter that should be determined is used as the time constant of the air flow sensor. The time constant is a function or table that takes the flow rate as a parameter, determines the time constant for each flow rate, and updates the function or table of the time constant based on the result of the determination. In block 1005, the air flow sensor detection value is corrected based on the determination result of the air flow sensor detection value and the sensor characteristic of the air flow sensor. The block diagram shown in FIG. 10 is applied in block 901 of the block diagram shown in FIG. 9 . At this time, either the corrected throttle valve flow calculation value or the corrected airflow sensor detection value can be applied to the output of block 901 . According to this method, the responsiveness of the calculation of the air cylinder inflow air amount at the transition time is equivalent to the responsiveness of the pressure sensor, and therefore the cylinder inflow air amount can be calculated without delay even at the time of transition. In addition, even if the flow rate characteristics of the throttle valve change due to the adhesion of deposits, etc., the flow rate characteristics of the throttle valve can be corrected using the intake air flow rate directly detected by the air flow sensor. The robustness of precision is high. In addition, regardless of transition or stabilization, since changes in the flow rate characteristics of the throttle valve or the sensor characteristics of the airflow sensor are sequentially corrected, there is no step difference when switching between transition and stabilization. The above-mentioned correction can be performed during operation of exhaust gas recirculation or a variable valve, and can be applied to an internal combustion engine equipped with an exhaust gas recirculation device or a variable valve mechanism.

FIG. 11 is a diagram illustrating a difference between a detected value or a calculated value of a throttle valve passing flow rate and a true value under an acceleration condition in which the throttle valve opening degree is increased from a low load state depending on the air metering method. Here, the air measurement method ① is the method shown in FIG. 4 in which the air flow into the cylinder is calculated only by the air flow sensor, and the air measurement method ② is the calculation of the air flow into the air cylinder only by the pressure sensor. The method shown in FIG. 5, again, the so-called air measurement method ③, is the method shown in FIG. 7 that uses both the air flow sensor and the pressure sensor to calculate the amount of air flowing into the air cylinder. If the throttle valve is suddenly opened at time T ₀ , the true value of the throttle valve flow rate temporarily overshoots (overshoots), and then displays a stable value. However, in the air metering method (1), the throttle flow rate detected by the airflow sensor is restricted by the responsiveness of the airflow sensor, and is delayed and shifted with respect to the true value. On the other hand, in the air metering method ③, the throttle flow rate is calculated based on a relatively high-response pressure sensor downstream of the throttle valve, so it is possible to capture the overshoot behavior that can be seen as a true value with high response.

FIG. 12 is a diagram illustrating a difference between a detected value or a calculated value of the intake pressure and a true value under an acceleration condition in which the throttle valve opening degree is increased from a low load state depending on the air metering method. If the throttle valve is opened sharply at time T ₀ , the true value of the suction pressure increases with a delay and thereafter shows a stable value. However, in the air metering method ①, the intake pressure calculated from the detected value of the airflow sensor is delayed and shifted from the true value. In the air metering method ②, the suction pressure is directly detected based on a relatively high-response pressure sensor, and therefore, the true value can be captured with high response. In addition, in the air metering method ③, the intake pressure is calculated based on the throttle flow rate calculated based on the pressure sensor detection value, and therefore, the true value can be captured with high response to the same extent as in the air metering method ②.

13 is a diagram illustrating the difference between the detected value or calculated value and the true value of the amount of air flowing into the air cylinder under the acceleration condition of increasing the throttle valve opening from the low load state due to the difference in the air metering method, and the difference due to the difference. A plot of the difference in behavior of the exhaust air-fuel ratio is produced. If the throttle valve is suddenly opened at time T ₀ , the true value of the cylinder flow rate increases with a delay in the same manner as the intake pressure, and then shows a stable value. However, in the air metering method ①, similarly to the transition of the calculation result of the intake pressure based on the detected value of the airflow sensor, it transitions with a delay from the true value. In the air metering method ②, the cylinder flow rate is calculated using the intake pressure directly detected by a relatively high-response pressure sensor, so transient behavior can be captured with high response. However, if the relationship between the pressure and the cylinder flow rate changes due to environmental changes, temporal deterioration of the internal combustion engine, solid variation, etc., a steady deviation occurs in the calculated value of the cylinder flow rate. On the other hand, in the air metering method ③, the throttle valve flow rate is calculated based on the pressure sensor detection value, and the intake pressure is calculated based on it. Therefore, the true value can be captured with high response to the same degree as the air metering method ②. Since it is corrected by the air flow sensor, there will be no stable deviation due to environmental changes, deterioration over time of the internal combustion engine, solid deviation, or the like. If the fuel injection control is performed based on the cylinder flow rate calculated in this way, in the air metering method ①, a transient error occurs on the leaning side during acceleration. In the air metering method ②, the transient error seen at the time of acceleration is suppressed, but on the other hand, a stable deviation due to environmental changes, deterioration over time of the internal combustion engine, solid deviation, etc. occurs. In the air metering method ③, the target air-fuel ratio can be accurately tracked at the time of stabilization and at the time of transition.

FIG. 14 is a diagram illustrating a difference between a detected value or a calculated value of a throttle valve passing flow rate and a true value under a deceleration condition in which the throttle valve opening degree is reduced from a high load state depending on the air metering method. If the throttle valve is suddenly closed at time _T0 , the true value of the throttle valve flow rate decreases in proportion to the throttle valve opening degree, and then shows a stable value. However, in the air metering method (1), the throttle flow rate detected by the airflow sensor is restricted by the responsiveness of the airflow sensor, and is delayed and shifted with respect to the true value. On the other hand, in the air metering method ③, the throttle valve flow rate is calculated based on the detection value of the relatively high-response pressure sensor downstream of the throttle valve, so it is possible to capture the throttle valve passage that can be regarded as a true value with high response. Flow reduction process.

FIG. 15 is a diagram illustrating a difference between a detected value or a calculated value of the intake pressure and a true value under a deceleration condition in which the throttle valve opening is decreased from a high load state depending on the air metering method. If the throttle valve is closed sharply at time T ₀ , the actual value of the suction pressure decreases with a delay and thereafter shows a stable value. However, in the air metering method ①, the intake pressure calculated based on the air flow sensor detection value is delayed and shifted from the true value. In the air metering method ②, the suction pressure is directly detected by a relatively high-response pressure sensor, so the true value can be captured with high response. In addition, in the air metering method ③, the intake pressure is calculated based on the throttle valve flow rate calculated based on the pressure sensor detection value, so the true value can be captured with high response to the same extent as in the air metering method ②.

16 is a diagram illustrating the difference between the detected value or the calculated value and the true value of the amount of air flowing into the air cylinder under the deceleration condition of reducing the throttle valve opening from the high load state due to the difference in the air metering method, and the difference due to the difference. A plot of the difference in behavior of the exhaust air-fuel ratio is produced. If the throttle valve is suddenly closed at time T ₀ , the true value of the cylinder flow rate decreases with a delay in the same manner as the intake pressure, and then shows a stable value. However, in the air metering method ①, similarly to the transition of the calculation result of the intake pressure based on the detected value of the airflow sensor, it transitions with a delay from the true value. In the air metering method ②, the cylinder flow rate is calculated using the intake pressure directly detected by a relatively high-response pressure sensor, so transient behavior can be captured with high response. However, if the relationship between the pressure and the cylinder flow rate changes due to environmental changes, temporal deterioration of the internal combustion engine, solid variation, etc., a steady deviation occurs in the calculated value of the cylinder flow rate. On the other hand, in the air metering method ③, the throttle valve flow rate is calculated based on the pressure sensor detection value, and the intake pressure is calculated based on it. Therefore, the true value can be captured with high response to the same degree as the air metering method ②. Since it is corrected by the air flow sensor, there will be no stable deviation due to environmental changes, deterioration over time of the internal combustion engine, solid deviation, or the like. If the fuel injection control is performed based on the cylinder flow rate calculated in this way, in the air metering method ①, a transient error occurs on the slope side during deceleration. In the air metering method ②, the transient error seen at the time of deceleration is suppressed, but on the other hand, a stable deviation due to environmental changes, deterioration over time of the internal combustion engine, solid deviation, etc. occurs. In the air metering method ③, the target air-fuel ratio can be accurately tracked at the time of stabilization and at the time of transition.

Fig. 17 is a diagram illustrating the calculation or detection of the throttle valve flow rate, suction pressure, and air cylinder inflow air volume by the air metering method ③ of the present invention, and correcting the throttle valve caused by the fouling of the throttle valve based on the air flow sensor. The graph of the difference from the true value for the case of the change of the flow characteristic of , and the case of no correction. Here, as an example, the behavior when the flow coefficient decreases due to temporal deterioration (valve fouling) of the throttle valve under the condition of constant throttle valve opening and rotational speed of the internal combustion engine can be cited. If valve fouling begins to occur, the flow coefficient of the throttle valve decreases. The throttle valve flow coefficient is initially set to a value applied under the conditions of the internal combustion engine when it is shipped from the factory. Therefore, when the flow coefficient correction is not performed, the flow coefficient deviates from the true value due to valve fouling. On the other hand, since the flow rate of the throttle valve is directly detected in the air flow sensor, it is possible to capture the decrease in the flow rate due to valve fouling, and the decrease in the flow coefficient can be captured by sequentially correcting the flow coefficient using the actual measurement value of the air flow sensor. If valve fouling begins to occur, the throttle flow is reduced along with a decrease in the throttle flow coefficient. For the throttle valve flow coefficient, if the flow coefficient correction is not performed in the state where the initial value is set, the calculation result of the throttle valve flow rate will not change even if the valve is fouled, so it deviates from the true value. . On the other hand, since the flow rate of the throttle valve is directly detected in the air flow sensor, it is possible to capture the decrease in the flow rate due to valve fouling, correct the flow coefficient by using the actual measurement value of the air flow sensor, and use the corrected flow coefficient to calculate the throttle valve flow, thereby being able to catch a decrease in throttle valve flow. If valve fouling starts to occur, the suction pressure decreases along with the throttle flow reduction. On the other hand, when the throttle valve flow coefficient is not corrected with the initial value set, the intake pressure is calculated using the calculated value of the throttle flow rate estimated to be too large. Therefore, Results based on inspiratory pressure calculations are also overvalued. On the other hand, when the flow coefficient is corrected using the actual measured value of the airflow sensor, it is possible to capture a decrease in the intake pressure. If valve fouling begins, the cylinder flow is reduced along with the reduction in suction pressure. On the other hand, for the throttle valve flow coefficient, if the flow coefficient correction is not performed in the state where the initial value is set, the cylinder flow rate is calculated using the intake pressure that is too high to be evaluated. Therefore, the calculation based on the cylinder flow rate The results were also overrated. On the other hand, when the flow coefficient is corrected using the actual measured value of the airflow sensor, it is possible to catch a decrease in the cylinder flow rate. As described above, even when valve fouling occurs, by correcting the flow coefficient using the actual measurement value of the air flow sensor, the cylinder flow rate calculation can be performed with high accuracy, and the control accuracy of ignition timing and fuel injection can be improved.

Fig. 18 is a diagram illustrating a system according to Embodiment 2 including an exhaust gas recirculation control device for controlling an exhaust gas recirculation amount from a part of the exhaust gas discharged to the exhaust passage downstream from the turbine to the intake passage upstream of the compressor; Structure diagram. 1 to 23 of the symbols shown in FIG. 18 are the same as those shown in Embodiment 1 described in FIG. 1 , and differences from Embodiment 1 will be particularly described here. In the system of Embodiment 2, the turbocharger 24 is equipped. Downstream of the airflow sensor 2, a negative pressure valve 27 is assembled, and a negative pressure sensor 28 is assembled downstream thereof. The pressure in the region from the negative pressure valve 27 to the compressor 25 is detected by the negative pressure sensor 28, and the negative pressure valve 27 is feedback-controlled so that the detected pressure becomes a target negative pressure. As a result, EGR can be supplied stably even when the EGR flow rate is controlled at a low rate, and the accuracy of the EGR rate control can be improved. A turbine 26 is arranged downstream of the exhaust valve, and an exhaust purification catalyst 16 is arranged downstream of the turbine 26 . Exhaust gas flows back from downstream of the exhaust purification catalyst 16 to upstream of the compressor. With such a system configuration, EGR can be stably supplied even under an overfeed condition of the internal combustion engine.

FIG. 19 is a diagram illustrating a method of EGR control of the rotation speed and load in the system of Embodiment 2. FIG. Under low rotation speed and low load conditions, the pump loss is reduced by introducing internal EGR through the intake and exhaust phase variable valve. Under load conditions above medium load including an overshoot condition, the frequency of occurrence of knocking and the exhaust gas temperature are reduced by recirculating the exhaust gas cooled by the EGR cooling device from the downstream of the turbine to the upstream of the compressor. Since it is not necessary to perform fuel increase control aimed at the effect of lowering the exhaust gas temperature, fuel consumption can be reduced.

20 is a diagram illustrating a block diagram for controlling the amount of intake air in a cylinder required for fuel injection and ignition timing based on an airflow sensor and a pressure sensor in the system according to Embodiment 2. FIG. According to the method, in block 2001, based on the air flow sensor, the opening of the negative pressure valve, the atmospheric pressure, the atmospheric temperature detected by the temperature sensor built into the air flow sensor, and the downstream pressure of the negative pressure valve detected by the pressure sensor downstream of the negative pressure valve , Calculate the flow through the negative pressure valve. In block 2002, the EGR valve passing flow rate is calculated based on the negative pressure valve downstream pressure, the EGR valve opening degree, the EGR valve upstream temperature, and the EGR valve upstream pressure. In block 2003, the total gas balance calculation of the throttle valve upstream part is performed based on the negative pressure valve passing flow rate, the EGR valve passing flow rate, the negative pressure valve upstream state quantity (pressure, temperature, EGR rate), and the throttle valve flow rate. In block 2004 , the EGR balance calculation of the throttle valve upstream portion is performed based on the EGR valve passing flow rate, the throttle valve upstream state quantity (pressure, temperature, EGR rate), and the throttle valve flow rate. In block 2005 , based on the air volume and EGR volume upstream of the throttle valve, the atmospheric temperature, and the temperature upstream of the EGR valve, state quantities (pressure, temperature, EGR rate) upstream of the throttle valve are calculated. In block 2006 , based on the throttle valve opening degree, the state quantity upstream of the throttle valve, and the state quantity downstream of the throttle valve, the throttle valve passing flow rate is calculated. In block 2007, based on the throttle valve flow rate, throttle valve upstream state quantities (pressure, temperature, EGR rate), and the air flow rate drawn into the cylinder, the total gas balance calculation of the throttle valve downstream portion is performed. In block 2008 , based on the throttle valve flow rate, throttle valve upstream state quantities (pressure, temperature, EGR rate), and the air flow rate drawn into the cylinder, the EGR balance calculation of the throttle valve downstream portion is performed. In block 2009 , based on the air amount and EGR amount downstream of the throttle valve, and the state amount upstream of the throttle valve, state quantities downstream of the throttle valve (pressure, temperature, EGR rate) are calculated. In block 2010 , the amount of air flowing into the cylinder is calculated based on the rotation speed of the internal combustion engine, the phase of the intake and exhaust valves, and the state quantities (pressure, temperature, and EGR rate) in the intake pipe. With such a configuration, even during a transition of an internal combustion engine equipped with an exhaust gas recirculation device or a variable valve mechanism, the amount of air flowing into the cylinder can be accurately calculated and fuel injection and ignition timing can be accurately controlled.

21 is a diagram illustrating a block diagram of calculating the negative pressure valve passing air amount based on the detection value of the pressure sensor and correcting the calculated negative pressure valve passing air amount by the air flow sensor in the system according to the second embodiment. According to this method, in block 2101 , the flow through the negative pressure valve is calculated based on the negative pressure valve opening, the negative pressure valve upstream pressure, the negative pressure valve upstream temperature, and the negative pressure valve downstream pressure. In block 2102, the flow rate characteristic of the negative pressure valve is determined by using the flow rate through the negative pressure valve calculated above and the corrected air flow sensor detection value corrected in consideration of the sensor characteristics. Here, the parameter that should be determined is the flow coefficient of the negative pressure valve. In block 2103, the negative pressure valve flow calculation value is corrected based on the results of identification of the negative pressure valve passage flow rate and the negative pressure valve flow rate characteristic after the above calculation. In block 2104 , the sensor characteristic of the airflow sensor is determined based on the detected value of the airflow sensor and the corrected negative pressure valve flow rate calculation value corrected in consideration of the flow rate characteristic of the negative pressure valve. Here, the parameter that should be determined is used as the time constant of the airflow sensor. In block 2105, the air flow sensor detection value is corrected based on the determination result of the air flow sensor detection value and the sensor characteristic of the air flow sensor. The block diagram shown in FIG. 21 is applied to block 2001 of the block diagram shown in FIG. 20 . At this time, either the corrected negative pressure valve flow rate calculation value or the corrected airflow sensor detection value can be applied to the output of block 2001 . According to this method, the responsiveness of the calculation of the air cylinder inflow amount at the time of transition is equivalent to the responsiveness of the pressure sensor, and therefore the amount of cylinder inflow air can be calculated without delay even at the time of transition. In addition, even if the flow rate characteristics of the throttle valve change due to the adhesion of deposits, etc., the flow rate characteristics of the negative pressure valve can be corrected using the intake air flow rate directly detected by the air flow sensor. The robustness of precision is high. In addition, regardless of transition or stabilization, since changes in the flow rate characteristics of the throttle valve or the sensor characteristics of the airflow sensor are sequentially corrected, there is no step difference when switching between transition and stabilization. The above-mentioned correction can be performed during operation of exhaust gas recirculation or a variable valve, and can be applied to an internal combustion engine equipped with an exhaust gas recirculation device or a variable valve mechanism.

As described above, according to one aspect of the present invention, an air flow sensor is provided upstream of the throttle valve and a pressure sensor is provided downstream of the throttle valve, and the flow rate through the throttle valve is calculated based on the pressure sensor, and based on the calculated The throttle valve calculates the pressure downstream of the throttle valve through the flow rate, calculates the air intake volume of the cylinder based on the calculated downstream pressure of the throttle valve, and corrects the throttle based on the pressure sensor calculation based on the flow rate of the throttle valve detected by the air flow sensor Valve flow rate, correct the throttle valve flow characteristic value and sensor characteristic value so that the difference between the throttle valve flow rate estimated based on the pressure sensor and the throttle valve flow rate detected by the air flow sensor is less than the specified value. And at the time of transition, the cylinder air intake amount can be calculated with high accuracy.

In addition, according to another aspect of the present invention, a turbocharger is provided that converts the energy of the gas discharged from the gas cylinder into power by a turbine, and a compressor compresses the intake air, and a part of the exhaust gas is regenerated downstream of the turbine. An exhaust gas recirculation control device that circulates to the upstream of the compressor and controls the amount of exhaust gas recirculation, has a negative pressure valve upstream of the recirculation position of the exhaust gas, and a negative pressure sensor downstream of the negative pressure valve, based on the negative pressure sensor To calculate the throughput of the negative pressure valve, based on the flow rate of the negative pressure valve detected by the airflow sensor, the flow rate of the negative pressure valve based on the calculation of the negative pressure sensor is corrected, and the flow characteristic value of the negative pressure valve and the characteristic value of the sensor are corrected, so that Since the difference between the flow rate estimated by the sensor and the flow rate detected by the air flow sensor is equal to or less than a predetermined value, the cylinder intake air volume can be accurately calculated at steady state and transient state.

In addition, according to another aspect of the present invention, the means for controlling the fuel injection amount and the ignition timing are based on the cylinder intake air amount calculated by the means for calculating the cylinder intake air amount, so that it is possible to accurately Control the fuel injection amount and ignition timing, and can properly control the internal combustion engine.

In addition, according to another aspect of the present invention, the flow rate characteristic value of the throttle valve or the flow rate characteristic value of the negative pressure valve is set as the flow coefficient, so that the change in the flow coefficient due to valve fouling and the like can be reliably taken into consideration of the cylinder intake air volume. in operation.

In addition, according to another aspect of the present invention, the flow coefficient is a function or a table using the rotation speed of the internal combustion engine and the valve opening as parameters, and the flow coefficient is determined for each level of the rotation speed of the internal combustion engine and the valve opening, and is updated based on the determination result. The unit of the function or table of the flow coefficient, therefore, even when the flow coefficient becomes a different value due to the rotation speed of the internal combustion engine or the valve opening, the change of the flow coefficient due to valve fouling, etc. can be reliably calculated Considering the calculation of the air intake volume of the cylinder.

In addition, according to another aspect of the present invention, since the characteristic value of the air flow sensor is set to a time constant, the response delay of the air flow sensor can be reliably taken into consideration in the calculation of the cylinder intake air amount.

In addition, according to another aspect of the present invention, the time constant is a function or a table using the flow rate as a parameter, and the flow coefficient is determined for each flow rate, and the time constant is updated based on the result of the determination. Therefore, even when the time constant is due to Even when the flow rate is a different value, the response delay of the air flow sensor can be reliably taken into account in the calculation of the cylinder intake air amount.

In addition, according to another aspect of the present invention, under the operating conditions of the internal combustion engine in which the pulsation rate of the flow rate passing through the throttle valve or the negative pressure valve (ratio of the flow rate amplitude to the average flow rate) is equal to or less than a predetermined value, the correction is stopped. unit, therefore, it is possible to suitably prevent erroneous correction under operating conditions in which the detection accuracy of the air flow sensor is lowered.

In addition, according to another aspect of the present invention, under the operating condition of the internal combustion engine in which the front-rear differential pressure of the throttle valve or the negative pressure valve is equal to or less than a predetermined value, the means for correction is stopped, so that it is possible to appropriately prevent the detection accuracy of the air flow sensor from deteriorating. Error correction under operating conditions.

In addition, according to another aspect of the present invention, under the operating condition of the internal combustion engine in which the valve opening degree of the throttle valve or the negative pressure valve is equal to or less than a predetermined value, the means for correction is stopped, so that it is possible to appropriately prevent the detection accuracy of the air flow sensor from deteriorating. Error correction under operating conditions.

In addition, according to another aspect of the present invention, the correction method is the least squares method that minimizes the sum of squares of errors, and the predetermined value is within ±2%. Therefore, the flow rate due to valve fouling, etc. The variation of the coefficient can be reliably taken into account in the calculation of the cylinder air intake amount, and the response delay of the airflow sensor can be reliably taken into account in the calculation of the cylinder air intake amount.

In addition, according to another aspect of the present invention, the correction method is the least square method that minimizes the absolute value of the error, and the predetermined value is within ±2%. Therefore, the flow rate due to valve fouling, etc. The variation of the coefficient can be reliably taken into account in the calculation of the cylinder air intake amount, and the response delay of the airflow sensor can be reliably taken into account in the calculation of the cylinder air intake amount.

Explanation of symbols

1 internal combustion engine

2 Airflow sensor and suction temperature sensor

3 throttle valve

4 suction manifold

5 Suction pressure sensor

6 flow enhancement valve

7 fuel injection valve

8 Suction variable valve mechanism

9 Suction variable valve position sensor

10 Exhaust variable valve mechanism

11 Exhaust variable valve position sensor

12 spark plugs

13 knock sensor

14 crank angle sensor

15 Air-fuel ratio sensor

16 Exhaust purification catalyst

17 Oxygen sensor

18 EGR pipe

19 EGR cooling equipment

20 EGR valve upstream temperature sensor

21 EGR valve upstream pressure sensor

22 EGR valve

23 ECU (Electronic Control Unit)

24 booster turbine

25 compressors

26 turbines

27 negative pressure valve

28 negative pressure sensor

Claims (10)

1. A control device for an internal combustion engine, characterized in that, is a control device for an internal combustion engine provided with an airflow sensor upstream of a throttle valve and a pressure sensor downstream of said throttle valve, The control device has: a calculation unit for calculating the passing flow rate of the throttle valve based on the pressure sensor, calculating the pressure downstream of the throttle valve based on the calculated throttle valve passing flow rate, and calculating the pressure downstream of the throttle valve based on the calculated throttle valve flow rate; Downstream pressure, calculated cylinder suction volume; and a correction unit for correcting the throttle valve flow calculated based on the pressure sensor based on the throttle valve flow detected by the air flow sensor, The correcting means corrects a throttle flow characteristic value and a sensor characteristic value such that a difference between a throttle passing flow estimated based on the pressure sensor and a throttle passing flow detected based on the airflow sensor becomes a predetermined value or less. 2. A control device for an internal combustion engine, characterized in that, It is equipped with a turbocharger that converts the energy of the gas discharged from the gas cylinder into power by a turbine and compresses the intake air by a compressor, and recirculates a part of the exhaust gas downstream of the turbine to the compressor an exhaust gas recirculation control device that controls the amount of exhaust gas recirculation upstream, a negative pressure valve upstream of the exhaust gas recirculation position, a control device for an internal combustion engine that has a negative pressure sensor downstream of the negative pressure valve, The control device includes means for calculating the flow rate of the negative pressure valve based on the negative pressure sensor and correcting the flow rate of the negative pressure valve calculated by the negative pressure sensor based on the flow rate of the negative pressure valve detected by the air flow sensor. , The correcting means corrects the negative pressure valve flow characteristic value and the sensor characteristic value so that the difference between the negative pressure valve passing flow estimated based on the negative pressure sensor and the negative pressure valve passing flow detected based on the airflow sensor is a predetermined value or less. . 3. The control device for an internal combustion engine according to claim 1 or 2, wherein: A means for controlling a fuel injection amount and an ignition timing is provided based on the cylinder intake amount calculated by the means for calculating the cylinder intake amount. 4. The control device for an internal combustion engine according to claim 1 or 2, wherein: Make the flow characteristic value of the throttle valve or the flow characteristic value of the negative pressure valve flow coefficient, The flow coefficient is a function or a table using the rotation speed of the internal combustion engine and the valve opening as parameters, and the flow coefficient is determined for each level of the rotation speed of the internal combustion engine and the valve opening, and the flow coefficient is updated based on the determination result. function or table cell. 5. The control device for an internal combustion engine according to claim 1 or 2, wherein: Make the characteristic value of the airflow sensor a time constant, The time constant is a function or a table that uses flow as a parameter, and includes a unit that determines the flow coefficient for each flow rate and updates the function or table based on the result of the determination. 6. The control device for an internal combustion engine according to claim 1 or 2, wherein: means for stopping the correction under the operating condition of the internal combustion engine in which the pulsation rate of the flow rate passing through the throttle valve or the negative pressure valve is equal to or less than a predetermined value, wherein the pulsation rate is a ratio of a flow rate amplitude to an average flow rate . 7. The control device for an internal combustion engine according to claim 1 or 2, wherein: A means for stopping the correction is provided under an operating condition of the internal combustion engine in which the front-rear differential pressure of the throttle valve or the negative pressure valve is equal to or less than a predetermined value. 8. The control device for an internal combustion engine according to claim 1 or 2, wherein: Means for stopping the correction is provided under an operating condition of the internal combustion engine in which the valve opening of the throttle valve or the negative pressure valve is equal to or less than a predetermined value. 9. The control device for an internal combustion engine according to claim 1 or 2, wherein: The correction method is the least squares method that minimizes the sum of squares of errors, and the specified value is within ±2%. 10. The control device for an internal combustion engine according to claim 1 or 2, wherein: The correction method is the least square method to minimize the absolute value of the error, and the specified value is within ±2%.