JP7101844B1 - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inert gas amount which is a sum of the amount of water vapor contained in the intake gas sucked into a combustion chamber and the amount of EGR gas in consideration of the amount of water vapor contained in the atmosphere sucked into the intake passage and the amount of EGR gas. Provided is a control device for an internal combustion engine that can be appropriately controlled.
SOLUTION: A target inert gas amount sucked into a combustion chamber is calculated, the EGR valve is controlled based on the target inert gas amount, an actual EGR gas amount sucked into a combustion chamber is calculated, and combustion is performed. If the total amount of inert gas, which is the sum of the actual EGR gas amount and the water vapor amount, is insufficient for the target inert gas amount by detecting the amount of water vapor contained in the air sucked into the chamber, it is insufficient. A control device for an internal combustion engine that drives a water injector to inject water into the intake air based on the amount of insufficient inert gas.
[Selection diagram] Fig. 2

Description

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

In order to adequately control the internal combustion engine, it is important to calculate the amount of intake air sucked into the combustion chamber with high accuracy, and to perform fuel control and ignition control according to the amount of intake air. As a method of measuring the amount of air sucked into the combustion chamber of an internal combustion engine, a method of measuring the air flow rate by an air flow sensor (hereinafter referred to as AFS) provided in the intake passage on the upstream side of the throttle valve (hereinafter referred to as AFS method). A pressure sensor (hereinafter referred to as an intake passage pressure sensor) for measuring the pressure in the intake passage (intake manifold) on the downstream side of the throttle valve is provided, and the intake passage pressure measured by the intake passage pressure sensor is provided. And a method of estimating the amount of intake air sucked into the combustion chamber based on the rotation speed of the internal combustion engine (hereinafter referred to as an S / D method) are generally used. Further, there are those in which these sensors are juxtaposed and the respective methods are switched according to the operating state, or even in the AFS method, the pressure in the intake passage is measured and used.

Regarding fuel control, even if there is an error in the detected intake air amount in the combustion chamber, if feedback control is performed by the air-fuel ratio sensor, generally good controllability can be obtained. However, regarding ignition control, not only the rotation speed and the amount of intake air in the combustion chamber, but also other factors such as the temperature of the internal combustion engine, the knock generation status, the fuel properties, and the EGR rate (the ratio of the amount of EGR gas to the amount of intake air). , EGR: Exhaust Gas Recirculation), it is necessary to control at the ignition advance angle (hereinafter, MBT: Minimum Spark Advance for Best Torque) where the output is maximized. Among the above-mentioned factors affecting MBT, for example, the temperature of the internal combustion engine can be detected by the cooling water temperature sensor, the knock generation status can be detected by the knock sensor, and the fuel property can be determined to be regular gasoline or high-octane gasoline according to the knock generation status. You can judge.

By the way, regarding the EGR rate, a method of providing an EGR valve in the EGR passage connecting the exhaust passage and the intake passage and controlling the EGR amount by the valve opening degree (hereinafter referred to as an external EGR), and opening and closing of the intake valve and the exhaust valve. A variable valve timing mechanism (hereinafter referred to as VVT: Variable Valve Timing) that changes the timing is provided, and the exhaust is burned by changing the overlap period in which the intake valve and the exhaust valve are open at the same time depending on the valve opening / closing timing. There is a method of controlling the amount of EGR by remaining in the room (hereinafter referred to as internal EGR), and these may be used at the same time. In recent years, an internal combustion engine having an external EGR and an intake / exhaust VVT has become common in order to further reduce fuel consumption and output. When simply referred to as EGR and EGR rate in this application, it indicates an external EGR and an external EGR rate.

There is also a technique of injecting water into the intake air to lower the temperature in the combustion chamber by the latent heat of vaporization in the combustion chamber and suppress the occurrence of knocking. There are two types of water injection positions, one that injects water into the intake port and the other that injects water directly into the combustion chamber. It is possible to control the injection amount with higher accuracy, but the cost is high.

Dry air and fuel sucked into the combustion chamber directly contribute to combustion, and EGR and water vapor do not directly contribute to combustion. In other words, EGR and water vapor are inert gases that do not directly contribute to combustion, and although their components are different, their effects on combustion are similar. As the amount of inert gas increases, the combustion rate slows down and the position of MBT Changes.

Furthermore, water vapor is also contained in the atmosphere sucked into the intake passage, and the amount of water vapor contained in the atmosphere changes greatly depending on the weather, the outside air temperature, the season, and the like. The measured intake air amount includes water vapor in the atmosphere, which causes an error with respect to the dry air amount and an error with respect to the optimum fuel amount and ignition timing. Patent Document 1 and Patent Document 2 are known as techniques for these.

Japanese Unexamined Patent Publication No. 2018-13608 Patent No. 6292209

As a method of correcting the influence of air humidity, in Patent Document 1, a humidity sensor is provided in the intake passage, and the humidity in rainy weather is used as a reference. When the humidity in operation is lower than the humidity in rainy weather, It is configured to inject water into the intake air based on the difference. In this method, a large amount of water vapor that does not contribute to combustion is supplied during operation in a low humidity environment, and problems such as combustion failure may occur depending on the machine error of the internal combustion engine, etc., especially in low load operation. There is sex.

Further, as a method for adjusting the amount of EGR gas and the amount of water injection, in Patent Document 2, when the target EGR rate is transiently increased during acceleration, water is supplied according to the deviation of the actual EGR rate with respect to the target EGR rate caused by the response delay of the actuator or the like. Is configured to inject. In this method, water injection is performed only in the operating region of a medium load in which EGR is introduced, and the influence of atmospheric humidity is not taken into consideration. Further, in Patent Document 2, the water to be injected is premised on supercritical water or subcritical water, and in order to realize the temperature and pressure thereof, a significant increase in cost is involved.

Therefore, in the present application, an inert gas obtained by totaling the amount of water vapor and the amount of EGR gas contained in the intake gas sucked into the combustion chamber in consideration of the amount of water vapor contained in the atmosphere sucked into the intake passage and the amount of EGR gas. It is an object of the present invention to provide a control device for an internal combustion engine capable of appropriately controlling the amount.

The control device for an internal combustion engine according to the present application includes an EGR flow path that recirculates exhaust gas from an exhaust path to an intake path, an EGR valve that opens and closes the EGR flow path, and a water injector that injects water into intake air. An internal combustion engine control device that controls an internal combustion engine.
The target inert gas amount calculation unit that calculates the target inert gas amount to be sucked into the combustion chamber,
An EGR control unit that controls the EGR valve based on the target amount of inert gas,
An actual EGR amount calculation unit that calculates the actual EGR gas amount sucked into the combustion chamber,
A water vapor amount detection unit that detects the amount of water vapor contained in the atmosphere sucked into the combustion chamber, and
When the total amount of inert gas, which is the sum of the actual EGR gas amount and the water vapor amount, is insufficient with respect to the target inert gas amount, the water is based on the insufficient insufficient inert gas amount. It is equipped with a water injection control unit that drives the injector and injects water into the intake air.

According to the control device of the internal combustion engine according to the present application, when the target inert gas amount cannot be achieved due to the introduction of EGR gas, the jet water is supplied by the water injector to achieve the target inert gas amount. can. At this time, since the actual amount of EGR gas and the amount of water vapor contained in the atmosphere sucked into the combustion chamber are taken into consideration, the amount of insufficient inert gas can be calculated accurately, and the control accuracy of the amount of inert gas can be improved. Therefore, the combustion state can be accurately controlled by the amount of the inert gas. For example, due to the response delay of EGR valve control and the transfer delay by the intake path from the EGR valve to the combustion chamber, the response delay occurred in the actual EGR gas amount with respect to the target EGR gas amount, and the insufficient inert gas amount occurred. In some cases, water injection can accurately make up for the shortfall. Alternatively, when the pressure in the intake passage is high and the EGR gas cannot sufficiently return to the intake passage and the amount of insufficient inert gas occurs, the shortage can be accurately compensated by water injection.

It is a schematic block diagram of the internal combustion engine and the control device which concerns on Embodiment 1 of this application. It is a block diagram of the control device which concerns on Embodiment 1 of this application. It is a hardware block diagram of the control device which concerns on Embodiment 1 of this application. It is a figure for demonstrating the change of the output characteristic of an internal combustion engine with respect to the ignition timing by the change of the amount of inert gas which concerns on Embodiment 1 of this application. It is a figure for demonstrating the calculation of the dimensionless flow rate constant which concerns on Embodiment 1 of this application. It is a flowchart which shows the process of the control apparatus which concerns on Embodiment 1 of this application.

1. 1. Embodiment 1
The internal combustion engine control device 50 (hereinafter, simply referred to as a control device 50) according to the first embodiment will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an internal combustion engine 1 and a control device 50 according to the present embodiment, and FIG. 2 is a block diagram of the control device 50 according to the present embodiment. The internal combustion engine 1 and the control device 50 are mounted on the vehicle, and the internal combustion engine 1 serves as a driving force source for the vehicle (wheels).

1-1. Configuration of Internal Combustion Engine 1 First, the configuration of the internal combustion engine 1 will be described. The internal combustion engine 1 has a combustion chamber 25 that burns a mixture of air and fuel. The internal combustion engine 1 includes an intake passage 23 for supplying air to the combustion chamber 25 and an exhaust passage 17 for discharging the exhaust gas burned in the combustion chamber 25. The internal combustion engine 1 includes a throttle valve 6 that opens and closes the intake passage 23. The throttle valve 6 is an electronically controlled throttle valve that is opened and closed by an electric motor controlled by the control device 50. The throttle valve 6 is provided with a throttle opening sensor 7 that outputs an electric signal according to the opening degree of the throttle valve 6.

An air cleaner 24 for purifying the air sucked into the intake passage 23 is provided at the uppermost stream portion of the intake passage 23. In the intake passage 23 on the upstream side of the throttle valve 6, an air flow sensor 3 (hereinafter referred to as AFS3) that outputs an electric signal according to the flow rate of the intake air, which is the air sucked into the intake passage 23, and the intake passage 23 The air temperature sensor 4 that outputs an electric signal corresponding to the air temperature Ta, which is the temperature of the air sucked into the air, and the air that outputs an electric signal corresponding to the air humidity Ha, which is the humidity of the air sucked into the intake passage 23. A humidity sensor 5 is provided. The pressure in the intake passage 23 on the upstream side of the throttle valve 6 can be regarded as equal to the atmospheric pressure. An atmospheric pressure sensor 2 that outputs an electric signal corresponding to the atmospheric pressure Pa is provided outside the intake passage 23 (for example, inside the control device 50).

The atmospheric temperature sensor 4 and the atmospheric humidity sensor 5 may be integrated with the AFS 3 or may be separated from each other. Alternatively, the atmospheric temperature sensor 4 and the atmospheric humidity sensor 5 may be provided outside the intake passage 23 as in the atmospheric pressure sensor 2, and the atmospheric pressure sensor 2 may be provided with the atmospheric temperature sensor 4 and the atmospheric humidity sensor 5. It may be provided in the same place.

The portion of the intake passage 23 on the downstream side of the throttle valve 6 is an intake manifold 12. The internal combustion engine 1 includes an EGR flow path 21 that recirculates exhaust gas from an exhaust path 17 to an intake path 23 (in this example, an intake manifold 12), and an EGR valve 22 that opens and closes the EGR flow path 21. The EGR valve 22 is an electronically controlled EGR valve that is driven to open and close by an electric actuator such as an electric motor controlled by the control device 50. The EGR valve 22 is provided with an EGR opening sensor 27 that outputs an electric signal according to the opening degree of the EGR valve 22. The exhaust gas recirculated to the intake manifold 12 (hereinafter referred to as recirculated exhaust gas) and the intake air sucked into the intake manifold 12 are mixed and homogenized in the intake manifold 12. EGR is an acronym for Exhaust Gas Recirculation.

The intake passage 23 includes an intake passage pressure sensor 8 that outputs an electric signal corresponding to the intake passage pressure Pb, which is the gas pressure in the intake passage 23 (in this example, the intake manifold 12), and an intake passage 23 (this). In the example, an intake passage temperature sensor 9 that outputs an electric signal corresponding to the intake passage temperature Tb, which is the gas temperature in the intake manifold 12), is provided. The pressure sensor 8 in the intake passage and the temperature sensor 9 in the intake passage may be integrated or separated.

A fuel injector 13 that directly injects fuel into the combustion chamber 25 is provided. The fuel injector 13 may be provided so as to inject fuel into a portion on the downstream side of the intake manifold 12. Further, a water injector 28 for injecting water into the intake air is provided. In the present embodiment, the water injector 28 is provided so as to inject water directly into the combustion chamber 25. The water injector 28 may be provided so as to inject water into a portion on the downstream side of the intake manifold 12. The water injector 28 is supplied with water pressurized by a pressurizing pump from the water in the tank in which the water is stored.

The top of the combustion chamber 25 is provided with a spark plug that ignites a mixture of air and fuel, and an ignition coil 16 that supplies ignition energy to the spark plug. Further, at the top of the combustion chamber 25, an intake valve 14 for adjusting the amount of intake air sucked into the combustion chamber 25 from the intake passage 23 and an exhaust gas for adjusting the amount of exhaust gas discharged from the combustion chamber to the exhaust passage 17 are provided. A valve 15 is provided. The intake valve 14 is provided with an intake variable valve timing mechanism that changes the valve opening / closing timing. The exhaust valve 15 is provided with a variable exhaust valve timing mechanism that changes the opening / closing timing of the valve. The variable valve timing mechanisms 14 and 15 have an electric actuator. The crank shaft of the internal combustion engine 1 is provided with a crank angle sensor 20 that outputs an electric signal corresponding to the rotation angle thereof. The variable valve timing mechanism may or may not be provided on only one of the intake and the exhaust.

The exhaust passage 17 is provided with an air-fuel ratio sensor 18 that outputs an electric signal according to the air-fuel ratio AF (Air / Fuel), which is the ratio of air and fuel in the exhaust gas. Further, the exhaust passage 17 is provided with a catalyst 19 for purifying the exhaust gas.

1-2. Configuration of Control Device 50 Next, the control device 50 will be described. The control device 50 is a control device that controls the internal combustion engine 1. As shown in FIG. 2, the control device 50 includes an operating state detection unit 51, a water vapor amount detection unit 52, a dry intake gas amount calculation unit 53, a target inert gas amount calculation unit 54, an EGR control unit 55, and an actual EGR gas amount calculation. It includes a control unit such as a unit 56, a water injection control unit 57, an actual inert gas amount calculation unit 58, and an ignition control unit 59. Each of the control units 51 to 59 and the like of the control device 50 is realized by a processing circuit provided in the control device 50. Specifically, as shown in FIG. 3, the control device 50 has a processing unit 90 (computer) such as a CPU (Central Processing Unit) and a processing device 90 via a signal line such as a bus as a processing circuit. It includes a connected storage device 91, an input circuit 92 for inputting an external signal to the arithmetic processing unit 90, an output circuit 93 for outputting a signal from the arithmetic processing unit 90 to the outside, and the like.

The arithmetic processing device 90 includes an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, and various signal processing circuits. You may. Further, the arithmetic processing apparatus 90 may be provided with a plurality of the same type or different types, and each processing may be shared and executed.

The storage device 91 is provided with a volatile and non-volatile storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), and an EEPROM (Electrically Erasable Programmable ROM). The input circuit 92 includes an A / D converter or the like to which various sensors and switches are connected and the output signals of these sensors and switches are input to the arithmetic processing device 90. The output circuit 93 includes a drive circuit or the like to which an electric load is connected and a control signal is output from the arithmetic processing device 90 to the electric load.

Then, in each function of the control units 51 to 59 included in the control device 50, the arithmetic processing device 90 executes software (program) stored in the storage device 91 such as ROM and EEPROM, and inputs the storage device 91. It is realized by cooperating with other hardware of the control device 50 such as the circuit 92 and the output circuit 93. The setting data such as conversion coefficients Kev, Kve, target inert gas amount QINT, pressure ratio upper limit, and map data used by each control unit 51 to 56, etc. are ROM, EEPROM, etc. as a part of software (program). Etc. are stored in the storage device 91.

In the present embodiment, the input circuit 92 includes an atmospheric pressure sensor 2, AFS3, an atmospheric temperature sensor 4, an atmospheric humidity sensor 5, a throttle opening sensor 7, an intake passage pressure sensor 8, an intake passage temperature sensor 9, and an empty space. A fuel ratio sensor 18, a crank angle sensor 20, an accelerator position sensor 26, an EGR opening sensor 27, and the like are connected. The output circuit 93 includes a throttle valve 6 (electric motor), a fuel injector 13, a water injector 28, an intake variable valve timing mechanism 14, an exhaust variable valve timing mechanism 15, an ignition coil 16, an EGR valve 22 (electric actuator), and the like. It is connected. Various sensors, switches, actuators and the like (not shown) are connected to the control device 50.

As a basic control, the control device 50 calculates the fuel injection amount, ignition timing, etc. based on the output signals of various input sensors, and drives and controls the fuel injector 13, the ignition coil 16, and the like. The control device 50 calculates the output torque of the internal combustion engine 1 requested by the driver based on the output signal of the accelerator position sensor 26 and the like, and throttles the throttle so that the intake air amount realizes the required output torque. It controls the valve 6 and the like. Specifically, the control device 50 calculates the target throttle opening degree, and the electric motor of the throttle valve 6 so that the throttle opening degree detected based on the output signal of the throttle opening degree sensor 7 approaches the target throttle opening degree. Is driven and controlled. Further, the control device 50 calculates the target opening / closing timing of the intake valve and the target opening / closing timing of the exhaust valve based on the output signals of various input sensors, and the intake and exhaust variable valves are calculated based on each target opening / closing timing. The timing mechanisms 14 and 15 are driven and controlled.

<Operating state detection unit 51>
The operating state detection unit 51 detects the operating state of the internal combustion engine 1 and the vehicle. The operation state detection unit 51 detects various operation states based on output signals of various sensors and the like.

For example, the operating state detection unit 51 detects the crank angle θ and the rotation speed Ne of the internal combustion engine 1 based on the output signal of the crank angle sensor 20, and detects the throttle opening degree based on the output signal of the throttle opening sensor 7. Then, the opening degree Oe of the EGR valve 22 is detected based on the output signal of the EGR opening degree sensor 27. The operating state detection unit 51 detects the air-fuel ratio AF of the exhaust gas based on the output signal of the air-fuel ratio sensor 18, and detects the accelerator opening degree based on the output signal of the accelerator position sensor 26.

The operating state detection unit 51 detects the intake air amount QWAc sucked into the combustion chamber 25. In the present embodiment, the operating state detection unit 51 detects the intake air intake air flow rate Qwa passing through the throttle valve 6 based on the output signal of the AFS3. Here, the intake air intake air flow rate Qwa and the intake air amount QWAc are the air flow rate and the air amount of the moist air containing dry air and water vapor.

The operating state detection unit 51 integrates the intake air intake air flow rate Qwa [g / s] for one stroke, and determines the intake air intake air amount QWA [g / stroke] sucked into the intake passage 23 during one stroke. Calculated, the intake air intake air amount QWA is subjected to a primary delay filter process simulating the delay of the intake manifold 12, and the intake air amount QWAc [g / stroke] sucked into the combustion chamber 25 during one stroke is obtained. calculate. The operating state detection unit 51 may calculate the intake air amount QWAc based on the information of the pressure sensor or the like by using a known method without using the output signal of the AFS3.

The operating state detection unit 51 detects the atmospheric temperature Ta sucked into the intake passage 23, detects the atmospheric humidity Ha, and detects the atmospheric pressure Pa. In the present embodiment, the output signals of the atmospheric temperature sensor 4, the atmospheric humidity sensor 5, and the atmospheric pressure sensor 2 are used for each detection. The operating state detection unit 51 may be configured to acquire the atmospheric temperature Ta, the atmospheric humidity Ha, and the atmospheric pressure Pa from an external device such as an air conditioner device via communication.

In the present embodiment, the atmospheric humidity sensor 5 is of a type that detects relative humidity, for example, an electric resistance type sensor that detects by the electric resistance value of a humidity-sensitive material, or an electrostatic sensor element. It is a capacitance type that detects by capacitance. Therefore, the operating state detection unit 51 detects the relative humidity as the atmospheric humidity Ha. Here, the relative humidity indicates the ratio of the partial pressure of water vapor in the air to the saturated water vapor pressure determined by the temperature of the air, and even if the partial pressure of water vapor in the air is the same, the relative humidity is determined by the temperature. Change.

The operating state detection unit 51 detects the pressure Pb in the intake passage and detects the temperature Tb in the intake passage. In the present embodiment, the output signals of the intake passage pressure sensor 8 and the intake passage temperature sensor 9 are used for each detection.

The operating state detection unit 51 detects the exhaust passage pressure Pex, which is the gas pressure in the exhaust passage 17, and detects the exhaust passage temperature Tex, which is the gas temperature in the exhaust passage 17. In the present embodiment, the operating state detecting unit 51 determines the pressure in the exhaust passage Pex and the exhaust based on specific operating conditions such as the rotation speed, the intake air amount, the EGR rate, the atmospheric pressure Pa, the air-fuel ratio, and the ignition timing. Calculate the in-passage temperature Tex. At the time of this calculation, the exhaust passage pressure characteristic data in which the relationship between the specific operating state and the exhaust passage pressure Pex is predetermined, and the exhaust temperature characteristic in which the relationship between the specific operating condition and the exhaust passage temperature Tex is predetermined. Data is used. For each characteristic data, mathematical formulas such as map data and polynomials are used. Alternatively, a temperature sensor and a pressure sensor may be provided in the exhaust passage 17, and the output signals of the sensors may be used.

<Water vapor amount detection unit 52>
The water vapor amount detection unit 52 detects the amount of water vapor QVc contained in the atmosphere sucked into the combustion chamber 25. In the present embodiment, the water vapor amount detecting unit 52 detects the water vapor amount QVc based on the intake air amount QWAc, the atmospheric temperature Ta, the atmospheric humidity Ha, and the atmospheric pressure Pa detected by the operating state detecting unit 51. This will be described in detail below.

The water vapor amount detection unit 52 calculates the saturated water vapor pressure Ps [hPa] at the atmospheric temperature Ta [° C.] based on the atmospheric temperature Ta using the following equation.

As described above, the atmospheric humidity Ha is a relative humidity and indicates the ratio of the water vapor partial pressure Pv to the saturated water vapor pressure Ps. Therefore, the water vapor amount detection unit 52 calculates the water vapor partial pressure Pv [hPa] based on the saturated water vapor pressure Ps [hPa] and the atmospheric humidity Ha [% RH] calculated by the equation (1) using the following equation. ..

According to Dalton's law, the ratio of the amount of substance is equal to the ratio of pressure, so the ratio of the amount of substance of water vapor in the atmosphere, that is, the mole fraction χv of water vapor is expressed by the following equation. The mole fraction χv of water vapor can also be considered as the volume ratio of water vapor to the atmosphere.

Generally, the fuel injection amount is calculated by dividing the detected intake air amount QWAc by the target air-fuel ratio. However, since the detected intake air amount QWAc includes the water vapor amount, it is necessary to subtract the water vapor amount from the intake air amount QWAc in order to obtain an accurate air amount. For that purpose, the mass ratio of water vapor contained in the moist air is required. The proportion of water vapor in moist air is generally referred to as specific humidity q. The specific humidity q is expressed by the following equation using the density ρw of moist air, the density ρd of dry air, and the density ρv of water vapor.

From the generally known ideal gas state equation, the gas density ρ is expressed by the equation (5) using the gas pressure P, the gas temperature T, and the gas constant R, and the gas constant R of the gas is generally. It is represented by the formula (6) using a gas constant R0 and a gas molecular weight M.

Equations (7) and (8) express the density ρv of water vapor and the density ρd of dry air using the equations (5) and (6). Here, Mv is the molecular weight of water vapor, and Md is the molecular weight of dry air.

In the formula (9), the formula (7) and the formula (8) are substituted into the formula (4), and 18.015 is substituted into the molecular weight Mv of water vapor and 28.966 is substituted into the molecular weight Md of the dry air. The water vapor amount detection unit 52 uses the formula (9) to calculate the specific humidity q based on the atmospheric pressure Pa and the water vapor partial pressure Pv calculated by the formula (2).

When the AFS3 is a thermal type, there is a possibility that a detection error of the amount of moist air may occur due to the humidity of the intake air, and it is necessary to correct the error by using the humidity information. However, since the correction method is not included in the scope of the present application, it is assumed that the detection error of AFS3 due to humidity does not occur, or the amount of moist air whose error is corrected is output from AFS3. Since AFS3 uses thermal detection as an example, it is assumed that the mass flow rate [g / s] of moist air is detected.

The ratio of the flow rate Qv of the water vapor content to the moist air flow rate Qwa detected by AFS3 is indicated by the specific humidity q. Therefore, as shown in the equation (10), the water vapor amount detecting unit 52 multiplies the intake air amount QWAc [g / stroke] of the moist air by the specific humidity q calculated by the equation (9), and the combustion chamber 25 The amount of water vapor QVc [g / stroke] inhaled into the air is calculated.

<Dry intake air amount calculation unit 53>
As shown in the formula (11), the dry intake air amount calculation unit 53 subtracts the water vapor amount QVc from the intake air amount QWAc to calculate the dry intake air amount QDAc sucked into the combustion chamber 25.

Further, the dry intake air amount calculation unit 53 divides the dry intake air amount QDAc by a value obtained by multiplying the air density ρ0 in the standard atmospheric condition (for example, 1 atm, 25 ° C.) by the cylinder volume Vc, and the dry filling efficiency. Calculate Ecda. The dry filling efficiency Ecda is the ratio of the dry intake air amount QDAc to the air mass (ρ0 × Vc) in the standard atmospheric state satisfying the cylinder volume Vc.

<Target inert gas amount calculation unit 54>
The target inert gas amount calculation unit 54 calculates the target inert gas amount QINT to be sucked into the combustion chamber. The target inert gas amount calculation unit 54 calculates the target inert gas amount QINT based on the operating state such as the rotation speed Ne and the intake air amount information. For example, the relationship between the operating state and the target inert gas amount QINT is calculated with reference to the preset target gas amount setting map data. As the intake air amount information, the dry intake air amount QDAc or the dry filling efficiency Ecda calculated based on the dry intake air amount QDAc is used. As a result, the ratio of the dry intake air amount QDAc to be burned and the target inert gas amount QINT that affects combustion can be accurately controlled, and the control accuracy of the combustion state can be improved. In addition, the intake air amount QWAc of moist air may be used.

Generally, the inert gas introduced in the medium load range is typified by EGR, and is known to have the effect of improving fuel efficiency by reducing pumping loss and the like. In addition, the inert gas introduced in the high load region is typified by water, and it is known that it has the effect of expanding the knock limit of ignition timing, or the effect of suppressing fuel enrichment by causing the latent heat of water to cool the fuel. Has been done. The optimum amount of inert gas in consideration of these various effects is set in the map data and calculated as the target amount of inert gas QINT.

<Correlation between EGR gas and water vapor>
However, since the substances of EGR gas and steam are different, the degree of influence on combustion per unit mass is different. Therefore, it is necessary to manage EGR gas and water vapor with a common index. In the present embodiment, the target inert gas amount calculation unit 54 calculates the target inert gas amount QINt in which the inert gas amount is converted into the EGR gas equivalent amount. That is, the target inert gas amount calculation unit 54 calculates the target EGR gas amount as the target inert gas amount QINT. The target inert gas amount calculation unit 54 may calculate the target inert gas amount QINT by converting the inert gas amount into the equivalent amount of water vapor.

This will be described in detail below. The amount of inert gas may be indicated by the EGR rate Regr in EGR, for example. The EGR ratio Regr is generally the ratio of the amount of exhaust gas circulated from the EGR flow path to the amount of intake air, and is represented by the formula (12) using the CO2 concentration. In the formula (12), CO2_in indicates the CO2 concentration [vol%] of the inhaled gas, CO2_ex indicates the CO2 concentration [vol%] of the outside air gas circulated from the exhaust gas, and CO2_a indicates the CO2_a in the atmosphere. The CO2 concentration [vol%] is shown. Generally, the CO2 concentration in the atmosphere is about 0.038 [vol%].

The hydrocarbon combustion reaction equation when, for example, gasoline is used as the fuel is generally expressed by the equation (13).

Assuming that the average molecular formula of gasoline is C ₇ H ₁₄ , and the composition of air is "oxygen (O ₂ ): nitrogen (N ₂ ) = 21: 79", the combustion reaction when gasoline and air are completely burned at the theoretical air-fuel ratio. The formula is expressed by the formula (14), and it is shown that the amount of carbon dioxide (CO ₂ ) produced by combustion is equal to the amount of water (H ₂ O).

FIG. 4 shows the output characteristics of an internal combustion engine when the ignition timing SA is changed before and after MBT (Minimum advance for the Best Torque) under the operating conditions of a predetermined dry intake air amount and fuel injection amount, and the same dry suction. It shows the output characteristics of the internal combustion engine with respect to the change of the ignition timing SA when the introduction amount of the external EGR or the water injection amount is changed under the operating conditions of the air amount and the fuel injection amount. The MBT tends to change to the advance angle side regardless of whether the EGR rate is increased or the water injection amount is increased, and the output characteristics of the internal combustion engine with respect to the change in the ignition timing SA change in the same tendency. It was confirmed that. As shown in FIG. 4, the output characteristics of an internal combustion engine having an EGR rate of about 15% and the output characteristics of an internal combustion engine having a water injection pulse width of 3 ms have almost the same characteristics.

This indicates that there is a correlation between the amount of EGR gas, which is both inert gas, and the amount of water vapor, regarding the output characteristics of the internal combustion engine with respect to the change in ignition timing SA. The correlation is affected by operating conditions such as rotation speed and filling efficiency. Therefore, the conversion coefficient Kve from the amount of water vapor to the equivalent amount of EGR gas and the conversion coefficient Kev from the amount of EGR gas to the equivalent amount of water vapor are preset for each operating state such as the rotation speed and the filling efficiency. For example, map data or mathematical formulas in which the relationship between each conversion coefficient and the operating state is preset are used.

<EGR control unit 55>
The EGR control unit 55 controls the EGR valve based on the target inert gas amount QINT.

In the present embodiment, the EGR control unit 55 calculates the water exclusion target inert gas amount QINDAt excluding the water vapor amount QVc from the target inert gas amount QINT, and the EGR valve is based on the water exclusion target inert gas amount QINDAt. To control.

By excluding the water vapor amount QVc from the target inert gas amount QINT, the EGR gas amount can be controlled so that the target inert gas amount QINT, which is the sum of the EGR gas and the water vapor, is achieved. Therefore, the control accuracy of the target inert gas amount QINT can be improved.

In the present embodiment, as described above, the target inert gas amount QINT is calculated by converting the amount of inert gas into the amount equivalent to EGR gas. The EGR control unit 55 calculates the water vapor conversion amount QVINc obtained by converting the water vapor amount QVc into an EGR gas equivalent amount. For example, as shown in the following equation, the EGR control unit 55 calculates the water vapor conversion amount QVINc by multiplying the water vapor amount QVc by the conversion coefficient Kve that converts the water vapor amount into the EGR gas equivalent amount. As described above, the conversion coefficient Kve is set for each operating state so that the output characteristics of the internal combustion engine with respect to the change in the ignition timing SA corresponding to the gas amount before and after the conversion are the same.

As shown in the following equation, the EGR control unit 55 subtracts the water vapor conversion amount QVINc obtained by converting the water vapor amount QVc into the EGR gas equivalent amount from the target inert gas amount QINT, and obtains the water exclusion target inert gas amount QINDAt. calculate.

The EGR control unit 55 controls the EGR valve so that the amount of EGR gas matches the water exclusion target amount of inert gas QINDAt.

In this embodiment, in order to improve the control accuracy of the EGR gas amount, the flow rate calculation formula of the orifice, which is a theoretical formula of fluid dynamics in a compressible fluid, is used in which the flow near the EGR valve 22 is considered to be the flow before and after the throttle valve. It is used, and the intake passage pressure Pb, the exhaust passage pressure Pex, and the exhaust passage temperature Tex are also taken into consideration. That is, the EGR control unit 55 calculates the target opening degree of the EGR valve based on the water exclusion target inert gas amount QINDAt, the intake passage pressure Pb, the exhaust passage pressure Pex, and the exhaust passage temperature Tex, and targets the target. The EGR valve is controlled based on the opening degree.

Specifically, as shown in the following equation, the EGR control unit 55 divides the water exclusion target inert gas amount QINDAt [g / stroke] by the cycle Tst [s / stroke] of one stroke to turn on the EGR valve. The target EGR gas flow rate Qegrt [g / s] to pass through is calculated.

The EGR control unit 55 calculates the sound velocity αex of the exhaust gas based on the exhaust gas recirculation temperature Tex using the equation (18), and uses the equation (19) to determine the exhaust gas recirculation temperature Tex and the exhaust gas recirculation pressure Pex. Based on this, the exhaust gas density ρex is calculated. Here, R is a gas constant of the exhaust gas, and a preset value is used. κ is the specific heat ratio of the exhaust gas, and a preset value is used. Further, the EGR control unit 55 calculates the dimensionless flow rate constant σex based on the pressure ratio Pb / Pex of the pressure Pb in the intake passage to the pressure Pex in the exhaust passage using the equation (20). Here, Rp0 is a critical pressure ratio, which is about 0.528 in the case of air, and a value preset according to the exhaust gas is used. As shown in FIG. 5, when the pressure ratio Pb / Pex is equal to or less than the critical pressure ratio Rp0, the dimensionless flow rate constant σex becomes a constant value σex0, and when the pressure ratio Pb / Pex is larger than the critical pressure ratio Rp0. As the pressure ratio Pb / Pex increases, the dimensionless flow rate constant σex decreases, and when the pressure ratio Pb / Pex = 1, the dimensionless flow rate constant σex = 0. In addition, in order to reduce the calculation load, a map data version of the equation (18) to the equation (20) may be used.

Then, as shown in the following equation, the EGR control unit 55 divides the target EGR gas flow rate Qegrt by the sound velocity αex of the exhaust gas, the density ρex of the exhaust gas, and the dimensionless flow rate constant σex, and the target opening of the EGR valve. Calculate the area Segrt.

The EGR control unit 55 converts the target opening area Segrt of the EGR valve into the target opening of the EGR valve by using the conversion map data or the mathematical formula. The EGR control unit 55 drives and controls the electric actuator of the EGR valve so that the actual opening degree Oe approaches the target opening degree.

<Restriction on increase in opening when pressure Pb in the intake passage is high>
Further, when the pressure ratio Pb / Pex approaches 1, the dimensionless flow rate constant σex becomes close to 0, the target opening area Segrt fluctuates greatly due to pressure pulsation, and even if the target opening area Segrt is increased, EGR The gas flow rate cannot be increased.

Therefore, when the pressure ratio Pb / Pex is larger than the preset pressure ratio upper limit value, the EGR control unit 55 limits the increase in the opening degree of the EGR valve. For example, the upper limit of the pressure ratio is set to 0.95. For example, the EGR control unit 55 limits the pressure ratio Pb / Pex by the upper limit value of the pressure ratio. When the pressure ratio Pb / Pex before the upper limit limit is larger than the pressure ratio upper limit value, the pressure ratio Pb / Pex after the upper limit limit is set to the pressure ratio upper limit value. Then, the dimensionless flow rate constant σex of the equation (20) is calculated based on the pressure ratio Pb / Pex whose upper limit is limited.

When the pressure ratio Pb / Pex before the upper limit limit is larger than the pressure ratio upper limit value, the dimensionless flow rate constant σex becomes a predetermined value larger than 0 corresponding to the pressure ratio upper limit value, and the target opening area Segrt is set. , The dimensionless flow rate constant σex becomes a predetermined value corresponding to a predetermined value, and the increase in the opening degree is limited. When the upper limit of the opening degree is limited, the learning control of the opening degree of the known EGR valve may be stopped.

Even if the actual EGR gas amount QEGRc is insufficient for the water exclusion target inert gas amount QINDAt due to the upper limit of the opening of the EGR valve, as will be described later, the shortage is due to water vapor from the water injection. Since it is supplemented, the target inert gas amount QINT can be achieved with high accuracy, and the opening degree of the EGR valve can be prevented from being unnecessarily increased or fluctuated.

<Actual EGR gas amount calculation unit 56>
The actual EGR gas amount calculation unit 56 calculates the actual EGR gas amount QEGRc sucked into the combustion chamber. The actual EGR gas amount calculation unit 56 calculates the actual EGR gas amount QEGRc based on the opening degree Oe of the EGR valve and the pressure Pb in the intake passage.

In the present embodiment, in order to improve the calculation accuracy of the actual EGR gas amount, the flow rate calculation formula of the orifice of the EGR valve is used, and the pressure Pex in the exhaust passage and the temperature Tex in the exhaust passage are also taken into consideration. That is, the actual EGR gas amount calculation unit 56 calculates the actual EGR gas amount QEGRc based on the opening degree Oe of the EGR valve and the pressure Pb in the intake passage, the pressure Pex in the exhaust passage, and the temperature Tex in the exhaust passage. do.

The actual EGR gas amount calculation unit 56 converts the actual opening Oe detected by the EGR opening sensor 27 into the actual opening area Segrr of the EGR valve by using the conversion map data or the mathematical formula. Then, as shown in the following equation, the actual EGR gas amount calculation unit 56 multiplies the actual opening area Segrr by the sound velocity αex of the exhaust gas, the density ρex of the exhaust gas, and the dimensionless flow rate constant σex, and the actual EGR gas. Calculate the flow rate Qegrr.

The actual EGR gas amount calculation unit 56 integrates the actual EGR gas flow rate Qegrr [g / s] for one stroke, and calculates the recirculated EGR gas amount QEGR [g / stroke] that is returned to the intake passage 23 during one stroke. The calculated, primary delay filter processing simulating the delay of the intake manifold 12 with respect to the recirculated EGR gas amount QEGR is performed, and the actual EGR gas amount QEGRc [g / stroke] sucked into the combustion chamber 25 in one stroke is obtained. calculate.

<Water injection control unit 57>
When the total inert gas amount QINsum, which is the sum of the actual EGR gas amount QEGRc and the water vapor amount QVc, is insufficient with respect to the target inert gas amount QINT, the water injection control unit 57 lacks the insufficient inertness. Based on the gas amount QINlack, the water injector is driven to inject water into the intake air.

According to this configuration, when the target inert gas amount QINT cannot be achieved by introducing the EGR gas, the jet water is supplied by the water injector, and the target inert gas amount QINT can be achieved. At this time, since the actual EGR gas amount QEGRc and the water vapor amount QVc are taken into consideration, the insufficient inert gas amount can be calculated accurately, and the control accuracy of the inert gas amount can be improved. Therefore, the combustion state can be accurately controlled by the amount of the inert gas. For example, due to the response delay of EGR valve control and the transfer delay by the intake path from the EGR valve to the combustion chamber, the response delay occurred in the actual EGR gas amount with respect to the target EGR gas amount, and the insufficient inert gas amount occurred. In some cases, water injection can accurately make up for the shortfall. Alternatively, when the pressure Pb in the intake passage is high and the EGR gas cannot sufficiently return to the intake passage and the amount of insufficient inert gas occurs, the shortage can be accurately compensated by water injection.

In the present embodiment, as shown in the following equation, the water injection control unit 57 sums the actual EGR gas amount QEGRc and the water vapor conversion amount QVINc obtained by converting the water vapor amount QVc into the EGR gas equivalent amount, and the total is not. Calculate the amount of active gas QINsum. The water vapor conversion amount QVINc is calculated in the same manner as in the above equation (15). The water injection control unit 57 calculates the insufficient inert gas amount QINluck by subtracting the total inert gas amount QINsum from the target inert gas amount QINt. The water injection control unit 57 calculates the insufficient water vapor amount QV rack by multiplying the insufficient inert gas amount QIN rack by the conversion coefficient Kev that converts the EGR gas amount into the equivalent amount of steam. As described above, the conversion coefficients Kve and Kev are set for each operating state so that the output characteristics of the internal combustion engine corresponding to the change in the ignition timing SA corresponding to the gas amount before and after the conversion become the same.

The water injection control unit 57 calculates the injection water amount based on the insufficient steam amount QVlack, and calculates the on period of the water injector based on the injection water amount. For example, the insufficient water vapor amount QVlack is set to the jet water amount. The evaporation rate of the jet water and the adhesion rate to the wall surface may be taken into consideration. Then, the water injection control unit 57 drives the water injector on only during the ON period at a predetermined timing from the intake stroke to the compression stroke, and supplies water having a insufficient amount of steam QVlack to the combustion chamber.

<Actually inert gas amount calculation unit 58>
The actual inert gas amount calculation unit 58 calculates the actual inert gas amount QINr by summing the actual EGR gas amount QEGRc, the water vapor amount QVc, and the water jet amount QVinj injected by the water injected by the water injector. The amount of injected steam QVinj is calculated based on the amount of injected water. For example, the amount of injected water or the amount of insufficient steam QVlack is set to the amount of injected steam QVinj. The evaporation rate of the jet water and the adhesion rate to the wall surface may be taken into consideration.

In the present embodiment, as shown in the following equation, the actual inert gas amount calculation unit 58 includes the actual EGR gas amount QEGRc, the water vapor amount QVc, and the steam equivalent amount QVinj converted into the EGR gas equivalent amount. The actual amount of inert gas is calculated by adding up the amount converted to steam injected. In order to convert the amount of water vapor into the amount equivalent to EGR gas, the above-mentioned conversion coefficient Kve is multiplied by the amount of water vapor QVc and the amount of injected water vapor QVinj.

<Ignition control unit 59>
The ignition control unit 59 sets the ignition timing SA based on the actual inert gas amount QINr. The ignition control unit 59 controls the energization of the ignition coil 16 based on the ignition timing SA (ignition angle) and the crank angle. For example, the ignition control unit 59 sets the ignition timing SA of the MBT based on the actual inert gas amount QINr. Various correction controls such as knock control are performed for the set ignition timing SA.

As shown in FIG. 4, even under the operating conditions of the same fresh air amount and fuel injection amount, the MBT changes when the amount of the inert gas in the combustion chamber changes. Since the ignition timing SA is set based on the actual inert gas amount QINr, which is the sum of the actual EGR gas amount QEGRc, the water vapor amount QVc, and the injected water vapor amount QVinj, the ignition control should be performed accurately based on the MBT. It is possible to improve the control accuracy of the combustion state. Further, since each water vapor amount is converted into an EGR gas equivalent amount and the actual inert gas amount QINr is calculated so that the output characteristics of the internal combustion engine become the same with respect to the change of the ignition timing SA, the EGR of different substances is calculated. Even if the gas and water vapor are mixed at an arbitrary mixing ratio, the control accuracy based on the MBT can be improved.

In the present embodiment, the ignition control unit 59 has a first ignition timing SA1 when the amount of the inert gas is zero, and a second ignition timing SA2 when the amount of the inert gas is the target inert gas amount QINT. , And interpolate between the first ignition timing SA1 and the second ignition timing SA2 based on the actual inert gas amount QINr, and set the ignition timing SA. For example, linear interpolation is performed as shown in the following equation.

The ignition control unit 59 refers to the first ignition timing setting map data in which the relationship between the operating state such as the rotation speed and the dry filling efficiency Ecda and the first ignition timing SA1 is preset, and corresponds to the current operating state. 1 Ignition timing SA1 is calculated. Further, the ignition control unit 59 refers to the second ignition timing setting map data in which the relationship between the operating state such as the rotation speed and the dry filling efficiency Ecda and the second ignition timing SA2 is set in advance, and corresponds to the current operating state. The second ignition timing SA2 is calculated.

<Flow chart>
A schematic processing procedure (control method of the internal combustion engine 1) of the control device 50 according to the present embodiment will be described with reference to the flowchart shown in FIG. The processing of the flowchart of FIG. 7 is repeatedly executed at predetermined calculation cycles by the arithmetic processing apparatus 90 executing software (program) stored in the storage apparatus 91.

In step S01, as described above, the operating state detection unit 51 has the rotation speed Ne, the crank angle θ, the intake air amount QWAc, the atmospheric temperature Ta, the atmospheric humidity Ha, the atmospheric pressure Pa, the intake passage pressure Pb, and the intake passage. The operation state detection process for detecting the operation state of various internal combustion engines 1 such as the temperature Tb, the pressure in the exhaust passage Pex, and the temperature Tex in the exhaust passage is executed.

In step S02, as described above, the water vapor amount detection unit 52 executes the water vapor amount detection process for detecting the water vapor amount QVc contained in the atmosphere sucked into the combustion chamber 25. In the present embodiment, the water vapor amount detecting unit 52 detects the water vapor amount QVc based on the intake air amount QWAc, the atmospheric temperature Ta, the atmospheric humidity Ha, and the atmospheric pressure Pa.

In step S03, as described above, the dry intake air amount calculation unit 53 subtracts the water vapor amount QVc from the intake air amount QWAc to calculate the dry intake air amount QDAc sucked into the combustion chamber 25. To execute.

In step S04, as described above, the target inert gas amount calculation unit 54 executes the target inert gas amount calculation process for calculating the target inert gas amount QINT to be sucked into the combustion chamber. In the present embodiment, the target inert gas amount calculation unit 54 calculates the target inert gas amount QINt in which the inert gas amount is converted into the EGR gas equivalent amount. The target inert gas amount calculation unit 54 calculates the target inert gas amount QINT based on the operating state such as the rotation speed Ne, the dry intake air amount QDAc, or the dry filling efficiency Ecda.

In step S05, as described above, the EGR control unit 55 executes the EGR control process for controlling the EGR valve based on the target inert gas amount QINT. In the present embodiment, the EGR control unit 55 calculates the water exclusion target inert gas amount QINDAt excluding the water vapor amount QVc from the target inert gas amount QINT, and the EGR valve is based on the water exclusion target inert gas amount QINDAt. To control. Further, the EGR control unit 55 limits the increase in the opening degree of the EGR valve when the pressure ratio Pb / Pex of the intake passage pressure Pb to the exhaust passage pressure Pex is larger than the preset pressure ratio upper limit value. do.

In step S06, as described above, the actual EGR gas amount calculation unit 56 executes the actual EGR gas amount calculation process for calculating the actual EGR gas amount QEGRc sucked into the combustion chamber. In the present embodiment, the actual EGR gas amount calculation unit 56 determines the actual EGR gas amount QEGRc based on the opening degree Oe of the EGR valve, the pressure Pb in the intake passage, the pressure Pex in the exhaust passage, and the temperature Tex in the exhaust passage. calculate.

In step S07, as described above, when the water injection control unit 57 lacks the total inert gas amount QINsum, which is the sum of the actual EGR gas amount QEGRc and the water vapor amount QVc, with respect to the target inert gas amount QINt. Drives a water injector and executes a water injection control process for injecting water into the intake air based on the insufficient amount of insufficient inert gas QINlack. In the present embodiment, the water injection control unit 57 calculates the total inert gas amount QINsum by summing the actual EGR gas amount QEGRc and the water vapor conversion amount QVINc obtained by converting the water vapor amount QVc into the EGR gas equivalent amount. ..

In step S08, as described above, the actual inert gas amount calculation unit 58 totals the actual EGR gas amount QEGRc, the water vapor amount QVc, and the water jet amount QVinj injected by the water jet of the water injector, and the actual inert gas amount. The actual inert gas amount calculation process for calculating QINr is executed. In the present embodiment, the actual inert gas amount calculation unit 58 totals the actual EGR gas amount QEGRc, the steam conversion amount obtained by converting the steam amount QVc and the injected steam amount QVinj into the EGR gas equivalent amount, and the injected steam equivalent amount. Then, the actual amount of inert gas QINr is calculated.

In step S09, as described above, the ignition control unit 59 executes the ignition control process for setting the ignition timing SA based on the actual inert gas amount QINr. In the present embodiment, the ignition control unit 59 has a first ignition timing SA1 when the amount of the inert gas is zero, and a second ignition timing SA2 when the amount of the inert gas is the target inert gas amount QINT. , And interpolate between the first ignition timing SA1 and the second ignition timing SA2 based on the actual inert gas amount QINr, and set the ignition timing SA.

<Example of diversion>
(1) In the above-described first embodiment, the case where the internal combustion engine 1 is a gasoline engine has been described as an example. However, the embodiments of the present application are not limited to this. That is, the internal combustion engine 1 may be various internal combustion engines such as a diesel engine and an internal combustion engine that performs HCCI combustion (Homogeneous-Charge Compression Ignition Combustion).

(2) In the first embodiment described above, the case where the target inert gas amount calculation unit 54 calculates the target inert gas amount QINT by converting the inert gas amount into the EGR gas equivalent amount has been described as an example. However, the embodiments of the present application are not limited to this. That is, the target inert gas amount calculation unit 54 may calculate the target inert gas amount QINT by converting the inert gas amount into the water vapor equivalent amount. Then, each calculated value may be a value converted into a water vapor equivalent amount.

Although the present application describes exemplary embodiments, the various features, embodiments, and functions described in the embodiments are not limited to the application of a particular embodiment, either alone or. Various combinations are applicable to the embodiments. Therefore, innumerable variations not exemplified are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted.

1 internal combustion engine, 28 water injector, 50 internal combustion engine control device, 51 operating condition detection unit, 52 water vapor amount detection unit, 53 dry intake amount calculation unit, 54 target inert gas amount calculation unit, 55 EGR control unit, 56 actual EGR gas amount calculation unit, 57 water injection control unit, 58 actual inert gas amount calculation unit, 59 ignition control unit, Pa atmospheric pressure, Pb intake passage pressure, Pex exhaust passage pressure, QEGRc actual EGR gas amount, QINDAt water Exclusion target inert gas amount, QINlack insufficient inert gas amount, QINr actual inert gas amount, QINsum total inert gas amount, QINT target inert gas amount, QVINc water vapor conversion amount, QVc water vapor amount, QVinj jet water vapor amount, QVlac Insufficient water vapor amount, QWAc intake air amount, Qegrr actual EGR gas flow rate, Qegrt target EGR gas flow rate, SA ignition timing, SA1 first ignition timing, SA2 second ignition timing, Ta atmospheric temperature, Tb intake passage temperature, Tex exhaust passage Internal temperature, q specific humidity

Claims (11)

Control of an internal combustion engine that controls an internal combustion engine including an EGR flow path that recirculates exhaust gas from an exhaust path to an intake path, an EGR valve that opens and closes the EGR flow path, and a water injector that injects water into intake air. It ’s a device,
The target inert gas amount calculation unit that calculates the target inert gas amount to be sucked into the combustion chamber,
An EGR control unit that controls the EGR valve based on the target amount of inert gas,
An actual EGR gas amount calculation unit that calculates the actual EGR gas amount sucked into the combustion chamber, and
A water vapor amount detection unit that detects the amount of water vapor contained in the atmosphere sucked into the combustion chamber, and
If the total amount of inert gas, which is the sum of the actual EGR gas amount and the water vapor amount, is insufficient with respect to the target inert gas amount, the water is based on the insufficient insufficient inert gas amount. A control device for an internal combustion engine equipped with a water injection control unit that drives an injector and injects water into the intake air. The amount of intake air sucked into the combustion chamber is detected, the temperature of the atmosphere sucked into the intake passage is detected, the humidity of the atmosphere is detected, the atmospheric pressure is detected, and the gas pressure in the intake passage is used. Equipped with an operating state detector that detects the pressure in a certain intake passage,
The water vapor amount detecting unit detects the water vapor amount based on the intake air amount, the atmospheric temperature, the atmospheric humidity, and the atmospheric pressure.
The actual EGR gas amount calculation unit calculates the actual EGR gas amount based on the opening degree of the EGR valve and the pressure in the intake passage.
The control device for an internal combustion engine according to claim 1, wherein the water injection control unit totals the actual EGR gas amount and the water vapor amount to calculate the total inert gas amount. The target inert gas amount calculation unit calculates the target inert gas amount obtained by converting the inert gas amount into an EGR gas equivalent amount.
The water injection control unit according to claim 1 or 2 calculates the total inert gas amount by summing the actual EGR gas amount and the steam equivalent amount obtained by converting the steam amount into an EGR gas equivalent amount. Internal combustion engine control device. The EGR control unit calculates the water exclusion target inert gas amount excluding the water vapor amount from the target inert gas amount, and controls the EGR valve based on the water exclusion target inert gas amount. The control device for an internal combustion engine according to any one of 1 to 3. The target inert gas amount calculation unit calculates the target inert gas amount obtained by converting the inert gas amount into an EGR gas equivalent amount.
The EGR control unit calculates the water exclusion target inert gas amount by subtracting the water vapor conversion amount obtained by converting the water vapor amount into the EGR gas equivalent amount from the target inert gas amount, and the EGR gas amount is the EGR gas amount. The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the EGR valve is controlled so as to match the water exclusion target inert gas amount. The pressure in the intake passage, which is the gas pressure in the intake passage, is detected, the pressure in the exhaust passage, which is the gas pressure in the exhaust passage, is detected, and the temperature in the exhaust passage, which is the gas temperature in the exhaust passage, is detected. Equipped with an operating state detector
The EGR control unit calculates the target opening degree of the EGR valve based on the water exclusion target inert gas amount, the intake passage pressure, the exhaust passage pressure, and the exhaust passage temperature, and opens the target. The control device for an internal combustion engine according to claim 5, which controls the EGR valve based on the temperature. The pressure in the intake passage, which is the gas pressure in the intake passage, is detected, the pressure in the exhaust passage, which is the gas pressure in the exhaust passage, is detected, and the temperature in the exhaust passage, which is the gas temperature in the exhaust passage, is detected. Equipped with an operating state detector
The actual EGR gas amount calculation unit calculates the actual EGR gas amount based on the opening degree of the EGR valve, the pressure in the intake passage, the pressure in the exhaust passage, and the temperature in the exhaust passage. The control device for an internal combustion engine according to any one of 6 to 6. The pressure in the intake passage, which is the gas pressure in the intake passage, is detected, the pressure in the intake passage, which is the gas pressure in the intake passage, is detected, and the pressure in the exhaust passage, which is the gas pressure in the exhaust passage, is detected. Equipped with an operating state detector
In the EGR control unit, the actual EGR gas amount is insufficient with respect to the target inert gas amount, and the pressure ratio of the intake passage pressure to the exhaust passage pressure is a preset pressure ratio. The control device for an internal combustion engine according to any one of claims 1 to 7, wherein if the value is larger than the upper limit, the increase in the opening degree of the EGR valve is restricted. The actual inert gas amount calculation unit for calculating the actual inert gas amount by summing the actual EGR gas amount, the water vapor amount, and the water jet amount of the water injected by the water injector.
The control device for an internal combustion engine according to any one of claims 1 to 8, further comprising an ignition control unit that sets an ignition timing based on the actual amount of inert gas. The actual inert gas amount calculation unit totals the actual EGR gas amount, the steam equivalent amount obtained by converting the steam amount and the injected steam amount into the EGR gas equivalent amount, and the injected steam equivalent amount, and the actual inert gas amount is calculated. The control device for an internal combustion engine according to claim 9, wherein the amount of gas is calculated. The ignition control unit calculates the first ignition timing when the amount of the inert gas is zero and the second ignition timing when the amount of the inert gas is the target amount of the inert gas, and the first ignition timing. The control device for an internal combustion engine according to claim 9 or 10, wherein the ignition timing is interpolated between the ignition timing and the second ignition timing based on the actual inert gas amount, and the ignition timing is set.

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