JP7177385B2 - engine controller - Google Patents

Description

The present invention relates to control technology for an engine having 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 can be measured, for example, using a flow sensor installed upstream of the intake throttle valve, or estimated from the intake manifold pressure downstream of the throttle valve and the engine speed. It is known how to
Further, in Patent Document 1, during steady operation of the engine, the amount of intake air into the cylinder is calculated using the intake manifold pressure and the volumetric efficiency equivalent value, and the relationship between the throttle opening and the amount of intake air is learned. A method of calculating the intake air amount into the cylinder using this learning result during operation 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 reduces NOx emissions by recirculating part of the exhaust gas from the engine to the intake side to lower the combustion temperature in the cylinder. Therefore, when exhaust gas is recirculated by the EGR device, the amount of fresh air into the cylinder, which is the amount of air that contributes to combustion, decreases, and the amount of intake air (fresh air amount) into the cylinder necessary for controlling fuel injection is reduced. Accurate calculation becomes difficult.

In particular, since the EGR system is generally on/off controlled based on the operating state of the engine, when on/off of exhaust gas recirculation is switched, such as during transient operation, the amount of exhaust gas recirculation changes and the amount of exhaust gas recirculated into the cylinder changes. It becomes difficult to calculate the intake air amount accurately.
SUMMARY OF THE INVENTION It is an object of the present invention to provide an engine control system capable of accurately calculating the amount of intake air into a cylinder in an engine equipped with an EGR system. It is in.

To achieve the above object, an engine control apparatus according to the present invention controls an exhaust recirculation passage for recirculating a portion of engine exhaust to an intake passage, and an exhaust recirculation valve based on the operating state of the engine. and an exhaust gas recirculation control unit, wherein the value equivalent to the amount of exhaust gas recirculated by the exhaust gas recirculation path is a target exhaust gas recirculation amount equivalent value set based on the operating state of the engine. a target exhaust gas recirculation volumetric efficiency coefficient calculation unit that calculates the volumetric efficiency coefficient of the engine in a non-exhaust gas recirculation state; A recirculation volumetric efficiency coefficient calculation unit, a target exhaust gas recirculation amount calculation unit for calculating a value equivalent to the exhaust gas recirculation amount in the target exhaust gas recirculation state, and a current exhaust gas recirculation amount equivalent value based on the operating state of the engine. and the volumetric efficiency coefficient in the target exhaust gas recirculation state based on the ratio between the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state and the current exhaust gas recirculation amount equivalent value a volumetric efficiency coefficient calculation unit that calculates a current volumetric efficiency coefficient of the engine by interpolating the volumetric efficiency coefficient in the non-exhaust recirculation state, an engine rotation speed detector that detects the rotation speed of the engine; an intake pressure detector for detecting the intake pressure of the engine, wherein the volumetric efficiency coefficient calculation unit for target exhaust gas recirculation and the volumetric efficiency coefficient calculation unit for non-exhaust gas recirculation are adapted to the rotational speed of the engine and the intake pressure. The volumetric efficiency coefficient of the engine is respectively calculated based on the volumetric efficiency coefficient of the engine, and the target exhaust gas recirculation amount calculation section calculates the volumetric efficiency coefficient in the target exhaust gas recirculation state calculated by the target exhaust gas recirculation volumetric efficiency coefficient calculation section. and the engine speed and the intake pressure, the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state is calculated .

As a result, based on the ratio between the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state and the current exhaust gas recirculation amount equivalent value, there is a difference between the volumetric efficiency coefficient in the target exhaust gas recirculation state and the volumetric efficiency coefficient in the non-exhaust gas recirculation state. , the current volume efficiency factor is calculated. Therefore, even in an exhaust gas recirculation state that is not the target exhaust gas recirculation state, the volumetric efficiency coefficient can be calculated with high accuracy.
Furthermore, using the engine speed and intake pressure, the target exhaust gas recirculation volumetric efficiency coefficient calculation unit calculates the volumetric efficiency coefficient of the engine in the target exhaust gas recirculation state, and the non-exhaust gas recirculation volumetric efficiency coefficient calculation unit calculates the volumetric efficiency coefficient in the non-exhaust gas recirculation state. It becomes possible to easily calculate the volumetric efficiency coefficient of the engine at .
Further, by using the volumetric efficiency coefficient in the target exhaust gas recirculation state calculated by the target exhaust gas recirculation volumetric efficiency coefficient calculator, the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state can be easily calculated.
Further, preferably, the volumetric efficiency coefficient calculating section calculates the current exhaust gas recirculation amount equivalent value as a, the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state as b, and the volumetric efficiency coefficient in the target exhaust gas recirculation state as wEGR. , where woEGR is the volumetric efficiency coefficient in the non-exhaust recirculation state, Kve=(wEGR×(a/b)+(woEGR×(1-(a/b))), the volumetric efficiency of the current engine It is preferable to calculate the coefficient Kve.

As a result, 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 calculated based on the ratio between the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state and the current exhaust gas recirculation amount equivalent value. can be calculated .

Further , preferably , a recirculation valve opening degree detector for detecting the opening degree of the exhaust gas recirculation valve is provided, and the current exhaust gas recirculation amount calculation unit detects the opening degree of the exhaust gas recirculation valve, the rotational speed of the engine, and the intake air. The current exhaust gas recirculation amount equivalent value may be calculated based on the atmospheric pressure.

This makes it possible to easily calculate the current exhaust gas recirculation amount equivalent value.
Preferably, the exhaust gas recirculation amount equivalent value is an exhaust gas recirculation rate, which 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 apparatus of the present invention, even in an exhaust gas recirculation state other than the target exhaust gas recirculation state, the volumetric efficiency coefficient can be calculated with high accuracy. Also, the volumetric efficiency coefficient can be calculated with high accuracy, and the intake amount of fresh air into the cylinder can be calculated with high accuracy. 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.

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

An embodiment of the present invention will be described below 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 the vehicle as a drive source for traveling, and is, for example, a multi-cylinder gasoline engine, and only one cylinder is shown for simplicity in FIG. The engine 2 injects fuel into the intake port of each cylinder at an arbitrary injection timing and injection amount from the fuel injection valve 3 provided in each cylinder, and ignites the air-fuel mixture in the combustion chamber 5 with the spark plug 4. and combustible.

An intake passage 6 of the engine 2 is provided with an electronically controlled throttle valve 7 for adjusting the flow rate of fresh air.
The engine 2 is also provided with an EGR device 10 . The EGR device 10 includes an EGR passage 11 (exhaust recirculation passage) that communicates an intake passage 6 and an exhaust passage 8 of the engine 2 , and an EGR valve 12 (exhaust 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 allowing part of the exhaust gas (EGR gas) to flow into the intake passage 6 in this way, the combustion temperature in the cylinder is lowered, and the amount of NOx emissions from the engine 2 is reduced.

Furthermore, the engine 2 is provided with a rotational speed sensor 15 (engine rotational speed detector) that detects the rotational speed of the engine 2 . An intake manifold 17, which is 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 manifold pressure). Further, the EGR valve 12 is provided with an EGR opening sensor 19 (recirculation valve opening detector) that detects 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, non-volatile RAM, etc.), a timer, a central processing unit (CPU), etc., and a rotation speed sensor 15, Detected information from various sensors such as the intake manifold pressure sensor 18 and the EGR opening sensor 19 is input, and the volumetric efficiency coefficient is calculated based on the various information. The volumetric efficiency coefficient is an index of how easily fresh air enters the cylinder from the intake passage 6, and the amount of air that the cylinder takes in when the stroke volume is filled with air having the same density as that in the intake pipe. It is the ratio of the amount of air

The engine control unit 20 further calculates the intake amount of fresh air into the cylinder using the volumetric 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. Controls 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 electronically controlled throttle valve 7, and the opening of the EGR valve 12. FIG.

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 sets a target EGR rate (a value corresponding to the target exhaust gas recirculation amount) based on the load of the engine 2 and controls the opening of the EGR valve 12 . The EGR rate (exhaust gas recirculation rate) is the ratio of the flow rate of EGR gas to the flow rate of fresh air. The load of the engine 2 may be calculated based on 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.

For example, as shown in FIG. 2, the target EGR rate is set to change based on the load of the engine 2, decrease during low load and high load, and increase during medium load. This is to ensure combustion stability of the engine 2 when the load is low, and because the intake manifold pressure rises when the load is high, making it difficult for the exhaust gas to recirculate.
Also, 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. In addition, the volumetric efficiency coefficient has a different value when EGR is not introduced and when EGR is introduced, and when target EGR is introduced (target exhaust gas recirculation state), which is when EGR is introduced at the target EGR rate, the ratio of exhaust to intake increases. Therefore, the value is smaller than when EGR is not introduced (non-exhaust gas recirculation state).

Next, a method of calculating the volumetric efficiency coefficient when EGR is introduced will be described with reference to FIGS. 4 and 5. FIG. The engine control unit 20 of this embodiment calculates the volumetric efficiency coefficient not only when EGR is not introduced and when target EGR is introduced, but also when EGR is introduced at a non-target EGR rate.
FIG. 4 is a block diagram of the volumetric efficiency calculation unit 21 in the engine control unit 20. As shown in FIG. FIG. 5 is a map showing the relationship between the load of the engine 2 and the EGR rate, the intake manifold pressure, and the volumetric efficiency coefficient. The EGR rate map in FIG. 5 corresponds to FIG. 2, and the volumetric efficiency coefficient map corresponds to FIG.

As shown in FIG. 4, the engine control unit 20 includes a volumetric efficiency coefficient calculation unit 21 for calculating the volumetric efficiency coefficient Kve in the current operating state (current operating point) of the engine 2. 22 (non-exhaust gas recirculation volumetric efficiency coefficient calculation unit), target EGR introduction volumetric efficiency coefficient calculation unit 23 (target exhaust gas recirculation volumetric efficiency coefficient calculation unit), cylinder air amount calculation unit 24 (target exhaust gas recirculation exhaust gas recirculation volumetric efficiency coefficient correction EGR rate calculation section 25 (target exhaust gas recirculation amount calculation section), in-cylinder EGR rate calculation section 26 (current exhaust gas recirculation amount calculation section), and volumetric efficiency coefficient calculation section 27. I have it.

The EGR non-introduction volumetric efficiency coefficient calculation unit 22 confirms and stores 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 through tests or the like. A volumetric efficiency coefficient woEGR when EGR is not introduced is calculated using the map in which EGR is not introduced.
The relationship between the load and the intake manifold pressure is such that when the engine rotation speed Ne is constant, the intake manifold pressure increases as the load increases when EGR is not introduced, as shown by the dashed line c in FIG. It becomes a proportional relationship to Then, using a map provided for each engine rotation speed Ne, the volumetric 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 volumetric efficiency coefficient calculation unit 23 confirms and stores 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 by a test or the like in advance. A volumetric efficiency coefficient wEGR at the introduction of the target EGR is calculated using the existing map.
When the target EGR is introduced, the relationship between the load and the intake manifold pressure is such that when the engine rotation speed Ne is constant, the intake manifold pressure increases as the load increases, 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 speed Ne, the volumetric 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. It becomes a value smaller than the coefficient woEGR.

The in-cylinder air amount calculation unit 24 calculates the target EGR rate based on the volumetric efficiency coefficient wEGR at the introduction of the target EGR rate calculated by the target EGR introduction volumetric efficiency coefficient calculation unit 23 and the intake manifold pressure Pb input from the intake manifold pressure sensor 18. A load (charging efficiency Ec) at the time of introduction is calculated. The load (charging efficiency Ec) may be calculated, for example, by the following formula (1).
Load (charging efficiency Ec) = wEGR x (Pb/atmospheric pressure) x 100 (%) (1)
The volumetric efficiency coefficient correction EGR rate calculation unit 25 calculates the volumetric efficiency, which is the EGR rate at the time of target EGR introduction, based on the load (charging efficiency Ec) calculated by the in-cylinder air amount calculation unit 24 and the engine rotation speed Ne. An EGR rate b for coefficient correction (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 degree θegr of the EGR valve 12 input from the EGR opening sensor 19. Based on this, the EGR rate a (value corresponding to the current exhaust gas recirculation amount) at the current operating point is calculated using, for example, a map stored in advance.
The volumetric efficiency coefficient calculation unit 27 calculates the volumetric efficiency coefficient woEGR at the time of EGR non-introduction calculated in the EGR non-introduction volumetric efficiency coefficient calculation unit 22 and the volumetric efficiency coefficient woEGR at the time of target EGR introduction calculated in the target EGR introduction volumetric efficiency coefficient calculation unit 23. Based on the volumetric efficiency coefficient wEGR, the EGR rate b at the time of introduction of the target EGR calculated by the EGR rate calculation unit 25 for correcting the volumetric efficiency coefficient, and the EGR rate a at the current operating point calculated by the in-cylinder EGR rate calculation unit 26 to calculate the volumetric efficiency coefficient kve at the current operating point.

The volumetric 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 this embodiment includes the EGR device 10, and controls the EGR valve 12 so as to achieve the target EGR rate based on the load. Then, as the volumetric efficiency coefficients used to calculate the intake air amount of the engine 2, the volumetric efficiency coefficient woEGR when EGR is not introduced and the volumetric efficiency coefficient wEGR when the target EGR rate is introduced are calculated. However, immediately after switching the EGR valve 12 between non-introduction (valve closed) and introduction (valve open), the volumetric efficiency coefficient is between the value woEGR when EGR is not introduced and the value wEGR when the target EGR rate is introduced. Therefore, during such a transition, the volumetric efficiency coefficient becomes a value different from the value wEGR when the target EGR rate is introduced and the value woEGR when EGR is not introduced.

In contrast, in the present embodiment, the volumetric efficiency coefficient woEGR when EGR is not introduced and the volumetric efficiency coefficient wEGR when target EGR is introduced are interpolated to calculate the volumetric efficiency coefficient Kve when EGR is introduced.
Specifically, the volumetric efficiency coefficient woEGR when EGR is not introduced and the volumetric efficiency coefficient wEGR when the target EGR rate is introduced are calculated from the intake manifold pressure Pb and the engine rotation speed Ne, which represent the current operating point of the engine 2. Corresponds to the ratio between the EGR rate b at the time of target EGR introduction and the EGR rate a at the current operating point instead of selecting between when EGR is introduced and when not introduced and using it as the volumetric efficiency coefficient Kve at the current operating point. Then, the current volumetric efficiency coefficient Kve is set to a value between the volumetric efficiency coefficient woEGR when EGR is not introduced and the volumetric efficiency coefficient wEGR when target EGR is introduced.

In this manner, the volumetric efficiency coefficient Kve when EGR is introduced is set to a value between the volumetric efficiency coefficient woEGR when EGR is not introduced and the volumetric efficiency coefficient wEGR when target EGR is introduced based on the operating state of the engine 2. Even if the target EGR rate is not reached when EGR is introduced, the volumetric efficiency coefficient Kve can be calculated with high accuracy.
As a result, even in a situation where the opening of the EGR valve 12 is changing, such as in a transient operating state of the engine 2, the volumetric efficiency coefficient Kve can be used to accurately calculate the intake amount of fresh air into the cylinder. It is possible to accurately control the amount of fuel supply based on the intake amount of fresh air, thereby improving fuel efficiency.

Further, the volumetric efficiency coefficient calculator 27 calculates the current volumetric efficiency coefficient Kve of the engine by Kve=(wEGR×(a/b)+(woEGR×(1-(a/b))). The volumetric efficiency coefficient Kve of the engine can be obtained easily and accurately.
Thus, when setting the volumetric efficiency coefficient Kve between the volumetric efficiency coefficient woEGR when EGR is not introduced and the volumetric efficiency coefficient wEGR when target EGR is introduced, the EGR rate b when target EGR is introduced and the current operating point By using the ratio (a/b) to the EGR rate a, a weighted average with appropriate weighting between the volume efficiency coefficient woEGR when EGR is not introduced and the volume efficiency coefficient wEGR when target EGR is introduced is taken. , the volumetric efficiency coefficient Kve of the current engine can be calculated accurately.

In addition, this invention is not limited to the said embodiment. For example, in the above embodiment,
The volumetric efficiency coefficient woEGR or wEGR is calculated using the rotational speed Ne of the engine 2 and the intake manifold pressure Pb in the EGR non-introduction volumetric efficiency coefficient calculation unit 22 and the target EGR introduction volumetric efficiency coefficient calculation unit 23. Alternatively, the load of or an index corresponding to the load may be used for calculation.

Further, the EGR rate is calculated in the volumetric efficiency coefficient correction EGR rate calculation section 25 and the in-cylinder EGR rate calculation section 26, but instead of the EGR rate, the EGR amount (exhaust gas recirculation amount) or an index corresponding to the EGR amount is used. These ratios may be used for calculating the volumetric efficiency coefficient Kve in the volumetric efficiency coefficient calculator 27 .
In addition, in the present embodiment, the present invention is applied to a gasoline engine that injects fuel into an intake port. The present invention can be widely applied to various engines.

2 engine 11 EGR passage (exhaust 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 (recirculation valve opening detector)
20 engine control unit (exhaust gas recirculation control unit)
22 EGR non-introduction volumetric efficiency coefficient calculation unit (non-exhaust recirculation volumetric efficiency coefficient calculation unit)
23 Target EGR Introduction Volumetric Efficiency Coefficient Calculator (Target Exhaust Recirculation Volumetric Efficiency Coefficient Calculator)
24 In-cylinder air amount calculation unit (exhaust gas recirculation amount calculation unit during target exhaust gas recirculation)
25 EGR rate calculation section for volumetric efficiency coefficient correction (calculation section for exhaust gas recirculation amount during target exhaust gas recirculation)
26 In-cylinder EGR rate calculation unit (current exhaust gas recirculation amount calculation unit)
27 volumetric efficiency coefficient calculator

Claims (4)

an exhaust gas recirculation passage for recirculating a portion of engine exhaust to an intake passage; an exhaust gas recirculation valve for opening and closing the exhaust gas recirculation passage; an exhaust gas recirculation control unit for controlling the exhaust gas recirculation valve based on the operating state of the engine; An engine control device comprising
A target volume during exhaust gas recirculation for calculating a volumetric efficiency coefficient of the engine in a target exhaust gas recirculation state in which a value equivalent to the exhaust gas recirculation amount by the exhaust gas recirculation path is a target exhaust gas recirculation amount equivalent value set based on the operating state of the engine. an efficiency coefficient calculator;
a non-exhaust gas recirculation volumetric efficiency coefficient calculation unit that calculates a volumetric efficiency coefficient of the engine in a non-exhaust gas recirculation state where the exhaust gas recirculation amount equivalent value is 0;
a target exhaust gas recirculation time exhaust gas recirculation amount calculation unit that calculates a value equivalent to the exhaust gas recirculation amount 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 volumetric efficiency coefficient in the target exhaust gas recirculation state and the volumetric efficiency coefficient in the non-exhaust gas recirculation state based on the ratio between the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state and the current exhaust gas recirculation amount equivalent value. A volumetric efficiency coefficient calculation unit that interpolates and calculates the current volumetric efficiency coefficient of the engine;
an engine rotation speed detector that detects the rotation speed of the engine;
and an intake pressure detector that detects the intake pressure of the engine,
The target exhaust gas recirculation volumetric efficiency coefficient calculation unit and the non-exhaust gas recirculation volumetric efficiency coefficient calculation unit respectively calculate a volumetric efficiency coefficient of the engine based on the rotational speed and intake pressure of the engine,
The target exhaust gas recirculation exhaust gas recirculation amount calculation unit calculates, based on the volumetric efficiency coefficient in the target exhaust gas recirculation state calculated by the target exhaust gas recirculation volumetric efficiency coefficient calculation unit, the rotational speed of the engine, and the intake pressure, Calculating a value equivalent to the exhaust gas recirculation amount in the target exhaust gas recirculation state
An engine control device characterized by: The volumetric efficiency coefficient calculating section calculates the current exhaust gas recirculation amount equivalent value a, the exhaust gas recirculation amount equivalent value in the target exhaust gas recirculation state b, the volumetric efficiency coefficient in the target exhaust gas recirculation state wEGR, and the non-exhaust gas recirculation If the volumetric 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 the volumetric efficiency coefficient Kve of the current engine is calculated by: a recirculation valve opening detector that detects the opening of the exhaust recirculation valve;
2. The current exhaust gas recirculation amount calculation unit calculates the current exhaust gas recirculation amount equivalent value based on the opening degree of the exhaust gas recirculation valve, the rotational speed of the engine, and the intake pressure. 3. The control device for the engine according to 2 . 4. The engine control device according to claim 1 , wherein the exhaust gas recirculation amount equivalent value is an exhaust gas recirculation rate, which is a ratio of the exhaust gas recirculation amount to the intake air amount of the engine.

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