JP2020007940A - Engine control device - Google Patents

Abstract

To accurately calculate volumetric efficiency of an engine.SOLUTION: An engine control device comprises: an exhaust gas recirculation device including an exhaust gas recirculation passage and an exhaust gas recirculation valve; and a control unit for controlling the exhaust gas recirculation valve on the basis of an operation state of an engine. The control device comprises: a target EGR introduction-time volumetric efficiency coefficient calculation part 23 for calculating a volumetric efficiency coefficient EGR of the engine in a target exhaust gas circulation state; an EGR non-introduction-time volumetric efficiency coefficient calculation part 22 for calculating a volumetric efficiency coefficient woEGR of the engine in a non-exhaust gas circulation state; an EGR rate calculation part 25 for correcting a volumetric efficiency coefficient to calculate an EGR rate b in the target exhaust gas circulation state; an in-cylinder EGR rate calculation part 26 for calculating a current EGR rate a; and a volumetric efficiency coefficient calculation part 27 for calculating a volumetric efficiency coefficient Kve of the current engine by interpolating the volumetric efficiency coefficient woEGR in the target exhaust gas circulation state and the volumetric efficiency coefficient woEGR in the non-exhaust gas circulation state on the basis of a ratio between the EGR rate b in the target exhaust gas circulation state and the current EGR rate a.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a control technique for an engine including an exhaust gas recirculation device.

In order to properly control the fuel injection of the engine, it is necessary to accurately calculate the amount of intake air into the cylinder. The amount of intake air into the cylinder is measured using, for example, a flow sensor provided upstream of the intake throttle valve, or estimated from the intake manifold pressure, which is the intake pressure downstream of the throttle valve, and the engine speed. There are known ways to do this.
Japanese Patent Application Laid-Open No. H11-157, in Japanese Patent Application Laid-Open No. H11-157, calculates the intake air amount into the cylinder using the intake manifold pressure and the value corresponding to the volume efficiency during steady operation of the engine, learns the relationship between the throttle opening and the intake air amount, At the time of operation, a method of calculating the intake air amount into the cylinder using the learning result is disclosed.

JP 2014-84817 A

  However, many engines are equipped with an EGR device (external EGR device) to reduce NOx emissions. The EGR device recirculates part of the exhaust gas of the engine to the intake side to lower the combustion temperature in the cylinder, thereby reducing the amount of NOx emission. Therefore, when exhaust gas is recirculated by the EGR device, the amount of fresh air into the cylinder, which is the amount of air contributing to combustion, decreases, and the amount of intake air (fresh air) into the cylinder required for fuel injection control is reduced. It becomes difficult to calculate accurately.

In particular, since the EGR device is generally controlled to be turned on / off based on the operating state of the engine, when the on / off of the recirculation of the exhaust is switched as in the transient operation, the amount of the recirculated exhaust gas changes, and the amount of the recirculated exhaust gas into the cylinder is changed. It becomes difficult to accurately calculate the intake air amount.
The present invention has been made in order to solve such a problem, and provides an engine control device that can accurately calculate an intake air amount into a cylinder in an engine including an EGR device. It is in.

  In order to achieve the above object, an engine control device of the present invention controls an exhaust gas recirculation valve that recirculates a part of exhaust gas of an engine to an intake passage, and the exhaust gas recirculation valve based on an operation state of the engine. An exhaust gas recirculation control unit, wherein the value corresponding to the amount of exhaust gas recirculated by the exhaust gas recirculation path is a value corresponding to a target amount of exhaust gas recirculated set based on the operating state of the engine. A target exhaust gas recirculation volume efficiency coefficient calculation unit for calculating a volume efficiency coefficient of the engine in a state, and a non-exhaust gas calculating a volume efficiency coefficient of the engine in a non-exhaust gas recirculation state in which the exhaust gas recirculation amount equivalent value is 0. A recirculation-time volume efficiency coefficient calculation unit, a target recirculation-time exhaust recirculation amount calculation unit for calculating an exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state, and a current exhaust gas recirculation amount based on the operating state of the engine. A current exhaust gas recirculation amount calculating unit for calculating an amount equivalent value, and the volume in the target exhaust gas recirculation state based on a ratio of the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state to the current exhaust gas recirculation amount equivalent value. A volume efficiency coefficient calculating unit configured to calculate a current volume efficiency coefficient of the engine by interpolating the efficiency coefficient and the volume efficiency coefficient in the non-exhaust gas recirculation state.

Thereby, based on the ratio between the value corresponding to the exhaust gas recirculation amount in the target exhaust gas recirculation state and the value equivalent to the current amount of exhaust gas recirculation, the volume efficiency coefficient in the target exhaust gas recirculation state and the volume efficiency coefficient in the non-exhaust gas recirculation state are , The current volume efficiency coefficient is calculated. Therefore, even in the exhaust gas recirculation state other than the target exhaust gas recirculation state, the volume efficiency coefficient can be accurately calculated.
Preferably, the volume efficiency coefficient calculation unit calculates the current exhaust gas recirculation amount equivalent value a, the target exhaust gas recirculation amount equivalent value b in the target exhaust gas recirculation state, and the volume efficiency coefficient wEGR in the target exhaust gas recirculation state. When the volume efficiency coefficient in the non-exhaust gas recirculation state is woGR, Kve = (wEGR × (a / b) + (woEGR × (1− (a / b))). The coefficient Kve may be calculated.

Thus, the volumetric efficiency coefficient of the engine in the exhaust gas recirculation state other than the target exhaust gas recirculation state can be easily and accurately determined based on the ratio between the target exhaust gas recirculation state equivalent value and the current exhaust gas recirculation amount equivalent value. It becomes possible to calculate.
Preferably, the engine further includes an engine rotational speed detector that detects a rotational speed of the engine, and an intake pressure detector that detects an intake pressure of the engine. The exhaust gas recirculation volume efficiency coefficient calculation unit may calculate the volume efficiency coefficient of the engine based on the rotation speed and the intake pressure of the engine.

Thus, using the engine speed and intake pressure, the target exhaust gas recirculation volume efficiency coefficient calculation unit calculates the engine volume efficiency coefficient in the target exhaust gas recirculation state, and the non-exhaust gas recirculation volume efficiency coefficient calculation unit calculates the non-exhaust gas recirculation volume efficiency coefficient. It is possible to easily calculate the volumetric efficiency coefficient of the engine in each state.
Also, preferably, the target exhaust gas recirculation exhaust gas recirculation amount calculation unit calculates the volume efficiency coefficient in the target exhaust gas recirculation state calculated by the target exhaust gas recirculation volume efficiency coefficient calculation unit, the rotation speed of the engine, and the intake pressure. Based on the above, a value corresponding to the exhaust gas recirculation amount in the target exhaust gas recirculation state may be calculated.

Thus, the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state can be easily calculated by using the volume efficiency coefficient in the target exhaust gas recirculation state calculated by the target exhaust gas recirculation volume efficiency coefficient operation unit.
Preferably, an engine rotational speed detector for detecting a rotational speed of the engine, an intake pressure detector for detecting an intake pressure of the engine, and a recirculation valve opening detector for detecting an opening of the exhaust recirculation valve The current exhaust gas recirculation amount calculation unit may calculate the current value of the exhaust gas recirculation amount based on the opening degree of the exhaust gas recirculation valve, the rotation speed of the engine, and the intake pressure.

This makes it possible to easily calculate the current value corresponding to the exhaust gas recirculation amount.
Preferably, the exhaust gas recirculation amount equivalent value is an exhaust gas recirculation rate that is a ratio of the exhaust gas recirculation amount to the intake air amount of the engine.
This makes it possible to calculate the volumetric efficiency coefficient of the engine based on the exhaust gas recirculation rate.

  According to the engine control device of the present invention, the volume efficiency coefficient can be accurately calculated even in the exhaust gas recirculation state other than the target exhaust gas recirculation state. In this case, the volume efficiency coefficient can be accurately calculated, and the amount of fresh air sucked into the cylinder can be accurately calculated. As a result, the fuel injection amount can be accurately controlled based on the intake amount of fresh air, and the fuel efficiency of the engine can be improved.

FIG. 1 is a schematic configuration diagram of an engine control device according to an embodiment of the present invention. 4 is an example of a map showing a relationship between an engine load and an EGR rate. 4 is an example of a map showing a relationship between an engine load and a volume efficiency coefficient. FIG. 3 is a block diagram illustrating a configuration of a volume efficiency coefficient calculation unit in the engine control unit of the embodiment. 4 is a map showing a relationship between an EGR rate, an intake manifold pressure, and a volume efficiency coefficient with respect to an engine load.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an engine 2 to which a control device 1 of the present invention is applied.
The engine 2 is mounted on a vehicle as a traveling drive source, and is, for example, a multi-cylinder gasoline engine, and FIG. 1 simply shows only one cylinder. The engine 2 injects fuel into an intake port of each cylinder at an arbitrary injection timing and injection amount from a fuel injection valve 3 provided in each cylinder, and ignites an air-fuel mixture in a combustion chamber 5 by a spark plug 4. It can be burned.

An electronically controlled throttle valve 7 for adjusting the flow rate of fresh air is provided in the intake passage 6 of the engine 2.
The engine 2 includes an EGR device 10. The EGR device 10 includes an EGR passage 11 (exhaust gas recirculation passage) that connects the intake passage 6 and the exhaust gas passage 8 of the engine 2, and an EGR valve 12 (exhaust gas recirculation valve) that opens and closes the EGR passage 11. The EGR device 10 recirculates part of the exhaust gas from the exhaust passage 8 to the intake passage 6 via the EGR passage 11. By causing a part of the exhaust gas (EGR gas) to flow into the intake passage 6 in this manner, the combustion temperature in the cylinder is reduced, and the emission amount of NOx from the engine 2 is reduced.

  Further, the engine 2 is provided with a rotation speed sensor 15 (engine rotation speed detector) for detecting the rotation speed of the engine 2. An intake manifold 17 at the end of the intake passage 6 on the engine 2 side is provided with an intake manifold pressure sensor 18 (intake pressure detector) for detecting intake pressure (intake pressure). Further, the EGR valve 12 is provided with an EGR opening sensor 19 (recirculation valve opening detector) for detecting the opening of the EGR valve.

  The engine control unit 20 (exhaust gas recirculation control unit) includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, and the like), a timer, a central processing unit (CPU), and the like. The detection information of various sensors such as the intake manifold pressure sensor 18 and the EGR opening degree sensor 19 is input, and the volume efficiency coefficient is calculated based on the various information. The volumetric efficiency coefficient is an index of the ease with which fresh air can enter the cylinder from the intake passage 6, and the cylinder takes in the amount of air when the air of the same density as in the intake pipe fills the stroke volume. It is the ratio of the amount of air that was removed.

  The engine control unit 20 further calculates the intake amount of fresh air into the cylinder using the volume efficiency coefficient, calculates the fuel injection amount of each cylinder based on the intake amount, and calculates the fuel injection amount from the fuel injection valve 3. Control fuel injection. The engine control unit 20 controls the operation of the engine 2 by controlling the ignition by the spark plug 4, the opening of the electronic control throttle valve 7, and the opening of the EGR valve 12.

FIG. 2 is an example of a map showing the relationship between the load of the engine 2 and the EGR rate. FIG. 3 is an example of a map showing the relationship between the load of the engine 2 and the volumetric efficiency coefficient.
The engine control unit 20 controls the opening of the EGR valve 12 by setting a target EGR rate (a value corresponding to a target exhaust gas recirculation amount) based on the load of the engine 2. The EGR rate (exhaust gas recirculation rate) is a ratio of the flow rate of the EGR gas to the flow rate of the fresh air. The load of the engine 2 may be calculated based on, for example, the engine rotation speed detected by the rotation speed sensor 15 and the intake manifold pressure detected by the intake manifold pressure sensor 18.

For example, as shown in FIG. 2, the target EGR rate changes based on the load of the engine 2, and is set to decrease at low load and high load, and increase at medium load. This is because the combustion stability of the engine 2 is ensured at a low load, and the exhaust gas hardly recirculates at a high load because the intake manifold pressure increases.
Further, the volumetric efficiency coefficient of the engine 2 changes according to the load. For example, as shown in FIG. 3, the volumetric efficiency coefficient increases as the load on the engine 2 increases. Further, the volumetric efficiency coefficient is different between when the EGR is not introduced and when the EGR is introduced, and when the target EGR is introduced (target exhaust gas recirculation state), which is the time when the EGR is introduced at the target EGR rate, the ratio of exhaust gas increases during intake. Therefore, the value becomes smaller than when EGR is not introduced (non-exhaust gas recirculation state).

Next, a method of calculating the volumetric efficiency coefficient when introducing EGR will be described with reference to FIGS. 4 and 5. The engine control unit 20 of the present embodiment calculates the volume efficiency coefficient not only when the EGR is not introduced and when the target EGR is introduced but also when the EGR is not the target EGR rate.
FIG. 4 is a block diagram of the volume efficiency coefficient calculation unit 21 in the engine control unit 20. FIG. 5 is a map showing the relationship between the EGR rate, the intake manifold pressure, and the volumetric efficiency coefficient with respect to the load of the engine 2. The solid line indicates when the target EGR rate is introduced, and the broken line indicates when EGR is not introduced. The map of the EGR rate in FIG. 5 corresponds to FIG. 2, and the map of the volume efficiency coefficient corresponds to FIG.

  As shown in FIG. 4, the engine control unit 20 includes a volume efficiency coefficient calculation unit 21 for calculating a volume efficiency coefficient Kve in the current operating state (current operating point) of the engine 2 and calculates a volume efficiency coefficient when no EGR is introduced. Unit 22 (volume efficiency coefficient calculating unit at non-exhaust gas recirculation), volume efficiency coefficient calculating unit at target EGR introduction 23 (volume efficiency coefficient calculating unit at target exhaust gas recirculation), in-cylinder air amount calculating unit 24 (target exhaust gas recirculation at exhaust gas recirculation) A flow rate calculating section), a volume efficiency coefficient correcting EGR rate calculating section 25 (target exhaust gas recirculation amount calculating section), an in-cylinder EGR rate calculating section 26 (current exhaust gas recirculating amount calculating section), and a volume efficiency coefficient calculating section 27. Have.

The EGR non-introduction volume efficiency coefficient calculation unit 22 confirms and stores in advance a test or the like based on the intake manifold pressure Pb input from the intake manifold pressure sensor 18 and the engine rotation speed Ne input from the rotation speed sensor 15, and stores the same. The volume efficiency coefficient woEGR when EGR is not introduced is calculated using the map.
The relationship between the load and the intake manifold pressure is, for example, when the engine rotational speed Ne is constant, as shown by the broken line c in FIG. 5, when the EGR is not introduced, the intake manifold pressure increases as the load increases. Is proportional. Then, using a map provided for each engine rotation speed Ne, a volume efficiency coefficient woEGR when EGR is not introduced is obtained based on the load d corresponding to the intake manifold pressure Pb.

The target EGR introduction volume efficiency coefficient calculation unit 23 confirms and stores in advance a test or the like based on the intake manifold pressure Pb input from the intake manifold pressure sensor 18 and the engine rotation speed Ne input from the rotation speed sensor 15 in advance. The volume efficiency coefficient wEGR at the time of introducing the target EGR is calculated using the map.
When the target EGR is introduced, the relationship between the load and the intake manifold pressure is, for example, assuming that the engine rotation speed Ne is constant, as shown by the solid line e in FIG. Although it increases, the intake manifold pressure increases more than when EGR is not introduced. Then, using a map provided for each engine rotation speed Ne, a volume efficiency coefficient wEGR when EGR is not introduced is obtained based on the load f corresponding to the intake manifold pressure Pb input from the intake manifold pressure sensor 18. When the engine rotation speed Ne is constant, the load f when the target EGR is introduced is smaller than the load d when the EGR is not introduced. Therefore, the volume efficiency coefficient wEGR when the target EGR is introduced is the volume efficiency when the EGR is not introduced. The value is smaller than the coefficient woEGR.

The in-cylinder air amount calculation unit 24 calculates the target EGR rate based on the volume efficiency coefficient wEGR at the time of introduction of the target EGR rate calculated by the target EGR introduction volume efficiency coefficient calculation unit 23 and the intake manifold pressure Pb input from the intake manifold pressure sensor 18. The load (filling efficiency Ec) at the time of introduction is calculated. The load (filling efficiency Ec) may be calculated by, for example, the following equation (1).
Load (filling efficiency Ec) = wEGR × (Pb / atmospheric pressure) × 100 (%) (1)
Based on the load (filling efficiency Ec) and the engine rotation speed Ne calculated by the in-cylinder air amount calculation unit 24, the volume efficiency coefficient correction EGR rate calculation unit 25 is a volume efficiency that is the EGR rate when the target EGR is introduced. A coefficient correction EGR rate b (a value corresponding to the exhaust gas recirculation amount in the target exhaust gas recirculation state) is calculated.

The in-cylinder EGR rate calculation unit 26 calculates the engine rotation speed Ne input from the rotation speed sensor 15, the intake manifold pressure Pb input from the intake manifold pressure sensor 18, and the opening θegr of the EGR valve 12 input from the EGR opening sensor 19. Based on this, for example, an EGR rate a (current exhaust gas recirculation amount equivalent value) at the current operating point is calculated using a map stored in advance.
The volume efficiency coefficient calculator 27 calculates the volume efficiency coefficient woEGR when the EGR is not introduced and is calculated by the EGR non-introduction volume efficiency coefficient calculator 22 and the volume efficiency coefficient when the target EGR is calculated and the target EGR is calculated when the target EGR is introduced. Based on the volume efficiency coefficient wEGR, the EGR rate b at the time of introducing the target EGR calculated by the volume efficiency coefficient correction EGR rate calculation section 25, and the EGR rate a at the current operating point calculated by the in-cylinder EGR rate calculation section 26. Then, the volume efficiency coefficient kve at the current operating point is calculated.

The volume efficiency coefficient Kve at the current operating point is calculated by the following equation (2).
Kve = wEGR × (a / b) + (woEGR × (1- (a / b)) (2)
As described above, the engine 2 of the present embodiment includes the EGR device 10 and controls the EGR valve 12 so that the target EGR rate is attained based on the load. Then, a volume efficiency coefficient woEGR when EGR is not introduced and a volume efficiency coefficient wEGR when the target EGR rate is introduced are respectively calculated as volume efficiency coefficients used for calculating the intake air amount of the engine 2. However, immediately after the EGR valve 12 is switched between non-introduction (closing) and introduction (opening), the volumetric efficiency coefficient is between the value woGR when the EGR is not introduced and the value wEGR when the target EGR rate is introduced. During such a shift, the volumetric efficiency coefficient is different from the value wEGR when the target EGR rate is introduced and the value woEGR when the EGR is not introduced.

On the other hand, in the present embodiment, the volume efficiency coefficient wve when the EGR is introduced is calculated by interpolating the volume efficiency coefficient woGR when the EGR is not introduced and the volume efficiency coefficient wEGR when the target EGR is introduced.
Specifically, a volume efficiency coefficient woEGR when the EGR is not introduced and a volume efficiency coefficient wEGR when the target EGR rate is introduced are calculated from the intake manifold pressure Pb and the engine rotation speed Ne representing the current operating point of the engine 2, respectively. Rather than selecting between EGR introduction and non-introduction to use as the volume efficiency coefficient Kve at the current operating point, it corresponds to the ratio between the EGR rate b at the time of introducing the target EGR and the EGR rate a at the current operating point. Then, the current volume efficiency coefficient Kve is set to a value between the volume efficiency coefficient woGR when the EGR is not introduced and the volume efficiency coefficient wEGR when the target EGR is introduced.

As described above, the volume efficiency coefficient Kve when the EGR is introduced is set to a value between the volume efficiency coefficient woEGR when the EGR is not introduced and the volume efficiency coefficient wEGR when the target EGR is introduced based on the operating state of the engine 2. Even when the target EGR rate does not reach the target EGR rate at the time of EGR introduction, the volume efficiency coefficient Kve can be accurately calculated.
Thus, even in a situation where the opening of the EGR valve 12 is changing, such as in a transient operation state of the engine 2, it is possible to accurately calculate the intake amount of fresh air into the cylinder using the volume efficiency coefficient Kve. Thus, the fuel supply amount can be accurately controlled based on the fresh air intake amount, and the fuel efficiency can be improved.

Further, the volume efficiency coefficient calculation unit 27 calculates the current volume efficiency coefficient Kve of the engine by Kve = (wEGR × (a / b) + (woEGR × (1− (a / b))). The volume efficiency coefficient Kve of the engine can be easily and accurately obtained.
As described above, when the volume efficiency coefficient Kve is set between the volume efficiency coefficient woGR when the EGR is not introduced and the volume efficiency coefficient wEGR when the target EGR is introduced, the EGR rate b when the target EGR is introduced and the current operation point By using the ratio (a / b) of the EGR rate a to the volume efficiency coefficient woGR when the EGR is not introduced and the volume efficiency coefficient wEGR when the target EGR is introduced, a weighted average is obtained. Thus, the volume efficiency coefficient Kve of the current engine can be accurately calculated.

Note that the present invention is not limited to the above embodiment. For example, in the above embodiment,
The EGR non-introduction volume efficiency coefficient calculation unit 22 and the target EGR inception volume efficiency coefficient calculation unit 23 calculate the volume efficiency coefficient woGR or wEGR using the rotation speed Ne of the engine 2 and the intake manifold pressure Pb. Alternatively, the calculation may be performed using the load or the index corresponding to the load.

Although the EGR rate is calculated by the volume efficiency coefficient correcting EGR rate calculation unit 25 and the in-cylinder EGR rate calculation unit 26, an EGR amount (exhaust gas recirculation amount) or an index corresponding to the EGR amount is used instead of the EGR rate. These ratios may be used to calculate the volume efficiency coefficient Kve in the volume efficiency coefficient calculation unit 27.
In the present embodiment, the present invention is applied to a gasoline engine that injects fuel into an intake port, but includes an EGR device such as an engine that injects fuel into a cylinder and a diesel engine that compresses and ignites. The present invention can be widely applied to various engines.

2 Engine 11 EGR passage (exhaust gas recirculation passage)
13 EGR valve (exhaust gas recirculation valve)
15 Rotation speed sensor (engine rotation speed detector)
18 intake manifold pressure sensor (intake pressure detector)
19 EGR opening sensor (reflux valve opening detector)
20 Engine control unit (exhaust recirculation control unit)
22 EGR non-introduction volume efficiency coefficient calculation unit (non-exhaust gas recirculation volume efficiency coefficient calculation unit)
23 Target EGR introduction volume efficiency coefficient calculation unit (Target exhaust gas recirculation volume efficiency coefficient calculation unit)
24 In-cylinder air amount calculation unit (target exhaust gas recirculation amount exhaust recirculation amount calculation unit)
25 Volume Efficiency Coefficient Correction EGR Rate Calculation Unit (Target Exhaust Gas Recirculation Exhaust Amount Calculation Unit)
26 In-cylinder EGR rate calculator (current exhaust gas recirculation amount calculator)
27 Volume efficiency coefficient calculator

Claims (6)

An exhaust gas recirculation path that recirculates part of the exhaust gas of the engine to the intake passage, an exhaust gas recirculation valve that opens and closes the exhaust gas recirculation path, and an exhaust gas recirculation control unit that controls the exhaust gas recirculation valve based on an operation state of the engine. An engine control device comprising:
A target exhaust gas recirculation volume for calculating a volume efficiency coefficient of the engine in a target exhaust gas recirculation state in which a value corresponding to the amount of exhaust gas recirculation by the exhaust gas recirculation path is a value corresponding to a target amount of exhaust gas recirculation set based on the operating state of the engine. An efficiency coefficient calculator,
A non-exhaust gas recirculation amount equivalent value of 0, a non-exhaust gas recirculation-time volume efficiency coefficient calculation unit for calculating a volume efficiency coefficient of the engine in a non-exhaust gas recirculation state,
A target exhaust gas recirculation amount calculating section for calculating an exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state,
A current exhaust gas recirculation amount calculation unit that calculates a current exhaust gas recirculation amount equivalent value based on the operating state of the engine;
The volume efficiency coefficient in the target exhaust gas recirculation state and the volume efficiency coefficient in the non-exhaust gas recirculation state based on a ratio of the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state to the current exhaust gas recirculation amount equivalent value. And a volume efficiency coefficient calculator for calculating the current volume efficiency coefficient of the engine by interpolating the above. The volume efficiency coefficient calculation unit calculates the current exhaust gas recirculation amount equivalent value a, the target exhaust gas recirculation amount equivalent value b in the target exhaust gas recirculation state, the volume efficiency coefficient in the target exhaust gas recirculation state wEGR, the non-exhaust gas recirculation When the volume efficiency coefficient in the state is woEGR,
Kve = (wEGR × (a / b) + (woEGR × (1− (a / b)))
2. The engine control device according to claim 1, wherein a volume efficiency coefficient Kve of the current engine is calculated by the calculation. An engine rotation speed detector that detects the rotation speed of the engine;
An intake pressure detector for detecting an intake pressure of the engine,
The target exhaust gas recirculation volume efficiency coefficient calculation unit and the non-exhaust gas recirculation volume efficiency coefficient calculation unit each calculate a volume efficiency coefficient of the engine based on a rotation speed and an intake pressure of the engine. The engine control device according to claim 1 or 2, wherein:   The target exhaust gas recirculation-time exhaust gas recirculation amount calculation unit is based on the volumetric efficiency coefficient in the target exhaust gas recirculation state calculated by the target exhaust gas recirculation-time volume efficiency coefficient operation unit, the rotation speed of the engine, and the intake pressure. The engine control device according to claim 3, wherein an exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state is calculated. An engine rotation speed detector that detects the rotation speed of the engine;
An intake pressure detector for detecting an intake pressure of the engine;
A recirculation valve opening detector for detecting an opening of the exhaust gas recirculation valve,
2. The current exhaust gas recirculation amount calculation unit calculates the current exhaust gas recirculation amount equivalent value based on an opening degree of the exhaust gas recirculation valve, a rotation speed of the engine, and intake pressure. The control device for an engine according to any one of claims 4 to 10.   The engine control device according to any one of claims 1 to 5, wherein the exhaust gas recirculation amount equivalent value is an exhaust gas recirculation rate that is a ratio of an exhaust gas recirculation amount to an intake amount of the engine.

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