JP2002349355A - Exhaust refluxing device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fully promote mixing of the intake air and EGR without reducing the volumetric efficiency in spite of a very simple structure. SOLUTION: A branching passage 8 is formed as a bypass of an intake throttle valve 7, and an EGR passage 18 is connected to the branching passage 8. An orifice 22 for disturbing the flow is provided in the branching passage 8. The branching passage 8 and an intake passage 2 are reconnected in the turbulence developing range of the intake air formed just after the intake throttle valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation system for an internal combustion engine (hereinafter, exhaust gas recirculation is also referred to as EGR). More specifically, the present invention promotes mixing of intake air and EGR gas to reduce EGR in each cylinder. The present invention relates to a technique for making the rate uniform.

[0002]

2. Description of the Related Art Nitrogen oxides (NO
EGR is an effective method for reducing x).
EGR is a technique for reducing the combustion temperature by recirculating a part of the exhaust gas to an intake system to suppress the generation of NOx. Until now, one of the problems in EGR equipment
One of the causes was a difference in specific gravity between the intake air and the EGR gas. That is, the two have different specific gravities, are hard to mix, and generally have different distances from the connection position of the EGR passage and the intake passage to each cylinder, so that the EGR rate varies among the cylinders. Another problem is that when the intake pressure and the exhaust pressure are close to each other, a desired amount of EGR cannot be obtained because an intake negative pressure required for EGR does not occur.

As a technique for solving such problems of uneven mixing of intake air and EGR gas and a shortage of EGR amount, a venturi type flow path has been conventionally provided in the intake passage downstream of the intake throttle valve. The formed one is disclosed (see JP-A-2000-329010). According to this technique, the EGR gas is sucked into the intake passage by the Venturi negative pressure, and the mixing with the intake air is promoted in the divergent portion.

[0004]

However, in such a configuration, the flow passage itself is always throttled regardless of the operation of the intake throttle valve, so that the volumetric efficiency of the intake system (the degree to which fresh gas enters) is reduced. ) Is reduced, and the fuel efficiency and the full-open output are reduced. Also, when the amount of intake air decreases, the amount of particulate matter discharged increases. And E
If the GR gas intake system introduction part is close to the intake throttle valve, EG
Particulate matter and hydrocarbons contained in the R gas may adhere to the valve and hinder its smooth operation.

[0005] As another technique for utilizing the Venturi negative pressure for EGR, a bypass passage for an intake throttle valve is formed in SAE2000-01-0225, and a Venturi pipe is interposed in the bypass passage so that the volume when fully opened is reduced. An arrangement for maintaining efficiency is disclosed. However, even with such a method, in order to sufficiently increase the degree of mixing of the EGR gas, the divergent portion at the rear of the venturi must be considerably lengthened, so that the intake system becomes large, and the layout in the engine room is reduced. It will be difficult. In addition, since the flow volume of the EGR gas increases with this, the responsiveness of the EGR also deteriorates.

[0006] In view of such circumstances, the present invention provides an internal combustion engine capable of sufficiently promoting the mixing of intake air and EGR gas with a very compact structure without lowering the volumetric efficiency. An object of the present invention is to provide an exhaust gas recirculation device. Further, the present invention provides an exhaust gas recirculation system for an internal combustion engine that operates in a state where the intake and exhaust differential pressure tends to be insufficient.
An object of the present invention is to generate a necessary suction negative pressure for the GR to obtain a sufficient EGR amount.

[0007]

Therefore, an exhaust gas recirculation system for an internal combustion engine according to the present invention is characterized in that, in an intake system, after branching from an intake passage from a branch portion on the upstream side of an intake throttle valve. An exhaust recirculation passage that extends from the exhaust passage by forming a branch passage that rejoins the intake passage at a recombining portion downstream of the intake throttle valve to form a branch of the intake air substantially along the flow in the intake passage; Is connected to the branch passage at a connection portion between the branch portion and the recombination portion, and the exhaust gas recirculation gas that is a part of the exhaust gas is transferred from the connection portion to the branch passage via the exhaust gas recirculation passage. The mixed gas of the exhaust recirculated gas and the intake air flowing in the branch passage is introduced into the intake passage from the recombining portion, and is mixed with the intake air through the intake throttle valve.

According to such a configuration, the EGR gas is
The air is mixed with the intake air in two stages, that is, the connection between the branch passage and the exhaust gas recirculation passage, and the recombination portion between the branch passage and the intake passage, and is diluted in each stage. An exhaust gas recirculation device for an internal combustion engine according to the second aspect of the present invention is an exhaust gas recirculation device for an internal combustion engine that recirculates a part of exhaust gas from a combustion chamber to an intake passage, wherein the intake air interposed in the intake passage is provided. A throttle valve, a branch passage detouring around the intake throttle valve, and extending substantially along the intake passage after branching off from the intake passage at a branch portion upstream of the intake throttle valve; A branch passage that rejoins the intake passage at a rejoining section downstream of the valve;
An exhaust gas recirculation passage connected to the branch passage at a connection between the branch portion and the recombining portion, and an exhaust gas recirculation control valve interposed in the exhaust gas recirculation passage are configured.

[0009] According to such a configuration, the EGR gas from the exhaust passage first flows into the branch passage, where it mixes with the branched flow of the intake air branched from the intake passage. further,
Downstream, it flows into the intake passage and mixes again with the intake air through the intake throttle valve. As described above, the EGR gas is mixed with the intake air in two stages, and is diluted in each stage.

According to a third aspect of the present invention, there is provided an exhaust gas recirculation apparatus for an internal combustion engine, wherein the branch passage is formed integrally with the intake passage adjacent to the intake passage. According to a fourth aspect of the present invention, in the exhaust gas recirculation device for an internal combustion engine, a turbulence promoting unit is provided in the branch passage on an upstream side of the connection portion. According to such a configuration, since the EGR gas flows into the flow of the intake air disturbed by the turbulence promoting means, the turbulent energy contributes to the dilution of the EGR gas.

According to a fifth aspect of the present invention, there is provided an exhaust gas recirculation system for an internal combustion engine, wherein the turbulence promoting means is an orifice. According to a sixth aspect of the present invention, in the exhaust gas recirculation device for an internal combustion engine, the recombining portion is formed in a turbulent flow development region of the intake air after passing through the intake throttle valve in the intake passage.

According to a seventh aspect of the present invention, in the exhaust gas recirculation device for an internal combustion engine, the exhaust gas recirculation passage extends from a downstream side of the exhaust aftertreatment device in the exhaust passage. An exhaust gas recirculation device for an internal combustion engine according to an eighth aspect of the invention is characterized in that a cooling device is interposed between the exhaust gas recirculation control valve and the exhaust gas passage in the exhaust gas recirculation passage.

According to a ninth aspect of the present invention, in the exhaust gas recirculation apparatus for an internal combustion engine, when the operating state is in the exhaust gas recirculation execution region, the exhaust gas recirculation control valve provided in the exhaust gas recirculation passage is controlled to fully open. The opening degree of the intake throttle valve is adjusted to control the exhaust gas recirculation amount.

[0014]

According to the first and second aspects of the present invention,
Since the EGR gas is mixed with the intake air in two stages, the dilution of the EGR gas is made uniform, and the EGR gas between the cylinders is reduced.
Variation in rate can be suppressed. Further, since the volumetric efficiency at the time when the intake throttle valve is fully opened is ensured, the fuel efficiency and the fully opened output are not reduced.

Further, since the branch passages are formed substantially along the intake passages, these passages can be made very compact. Therefore, installation in the engine room is easy and layout is good. According to the third aspect of the present invention, the production efficiency is improved and the layout is further improved.

According to the fourth aspect of the present invention, the turbulent energy promotes the dilution of the EGR gas at the connection between the branch passage and the exhaust gas recirculation passage.
The R rate can be made more uniform. According to the fifth aspect of the present invention, since a turbulence is formed in the branch passage by the orifice, and at the same time an effect of increasing the intake / exhaust differential pressure is obtained, the suction negative pressure required for EGR can be secured.

According to the sixth aspect of the present invention, the dilution of the EGR gas in the reconnection portion between the branch passage and the intake passage is promoted by the turbulent energy in the turbulent flow development region. The rate can be made more uniform. According to the seventh aspect of the present invention, since the exhaust gas after the post-processing is configured to be recirculated, the particulate matter and hydrocarbons contained in the EGR gas are significantly reduced. These substances are not fixed, and the smooth operation can be maintained.

According to the eighth aspect of the present invention, since the EGR control valve is located downstream of the cooling device, deterioration of the control valve based on the exhaust gas temperature can be suppressed. EG
Since the R control valve is arranged near the intake system, the responsiveness of EGR is improved. According to the ninth aspect, the EG
The control required for the EGR control valve at the time of performing R is only the full-open control, and the control of the EGR amount is performed by adjusting the opening degree of the intake throttle valve at the time of the full-open control of the control valve. Simplified.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a configuration of an internal combustion engine (diesel engine) 1 including an EGR device according to one embodiment of the present invention. Referring to FIG. 1, an air filter 3 is attached to an introduction portion of the intake passage 2. Here, dust and the like floating in the intake air are removed.

Immediately downstream of the air filter 3, a hot-wire type air flow meter 4 is installed, and its detection signal is
It is input to an electronic control unit (ECU) 101. EC
U101 determines the intake air amount Qai based on the input signal.
Calculate r. The engine 1 is provided with a variable nozzle type turbocharger 5, and the intake air via the air flow meter 4 is compressed by a compressor unit 51 and sent out. An intercooler 6 is provided in the intake passage 2 together with the turbocharger 5.
The intake air pumped from 1 is cooled here.

An intake throttle valve 7 is provided downstream of the intercooler 6. The intake throttle valve 7 is provided by the ECU 101
Driven by a drive motor 71 that receives a control signal from the controller, the opening degree of the intake passage 2 is adjusted. Also, Engine 1
Is provided with a branch passage 8 as a bypass that bypasses the intake throttle valve 7 in the intake system.

Accordingly, the intake air is divided into the intake passage 2 and the branch passage 8, and the intake air flowing through the intake passage 2 as it is passes through the intake throttle valve 7, and the intake air flowing through the other branch passage 8 is: Bypass the intake throttle valve 7. They are,
Thereafter, they merge and proceed further downstream, and are distributed to each cylinder in the manifold section 9. In the combustion chamber 10, an injector 11 and a glow plug 12 are installed so as to face substantially the upper center. The fuel pumped by the high-pressure fuel pump 13 is supplied to the injector 11 via a fuel supply pipe 14 and a common rail 15 which constitutes a part thereof.

In the exhaust system, a turbine section 52 of the turbocharger 5 is provided in the exhaust passage 16. An exhaust after-treatment device 17 is attached downstream of the turbine section 52, and one end of the EGR passage 18 is connected further downstream thereof. Therefore, the exhaust gas from which most of the particulate matter and 90% or more of the hydrocarbons have been removed by the after-treatment flows into the EGR passage 18, so that the circulation of these substances to the intake system can be suppressed. . Thereby, it is possible to prevent the particulate matter using the hydrocarbon as a medium from sticking to the intake throttle valve 7 and the intake system pipe wall surface. The other end of the EGR passage 18 is connected to the branch passage 8 in the intake system.

A cooling device (EGR cooler) 19 is attached to the EGR passage 18, and a control valve (EGR control valve) 20 is installed downstream of the cooling device. Therefore, EG
The R control valve 20 is not exposed to the uncooled high-temperature exhaust gas, and the failure of the EGR control valve 20 due to the exhaust gas temperature is prevented. In such a configuration, the EGR
Since the control valve 20 is disposed at a position relatively close to the intake throttle valve 7, the responsiveness of EGR is improved.

The EGR control valve 20 is driven by a solenoid type driving device 21 which receives a control signal from the ECU 101, and sets the EGR passage 18 to either fully open or fully closed according to the operation state. When fully opened, the amount of EGR gas corresponding to the intake / exhaust differential pressure is recirculated to the intake passage 2. Other sensors provided in the engine 1 include a cooling water temperature (water temperature) sensor 31, a crank angle sensor 32, and the like. These detection signals are all EC
It is input to U101.

FIG. 2 is an enlarged view of the intake throttle valve 7 and its peripheral structure (an EGR gas diluting section D indicated by a two-dot chain line in FIG. 1). The engine 1 includes the branch passage 8 as a bypass that bypasses the intake throttle valve 7 as described above. The branch passage 8 branches from the intake passage 2 at a branch portion 201 upstream of the intake throttle valve 7 (downstream of the engine 1 with the intercooler 6).
Along and adjacent to each other with a common pipe wall interposed therebetween. Then, it is recombined with the intake passage 2 at the recombining section 202 immediately after the intake throttle valve 7 and ends here.

In the intake passage 2, the intake air passing through the intake throttle valve 7 becomes a jet stream by passing through the valve, and forms a turbulent flow development region behind the valve. The recombination unit 202 is provided in this turbulence development area. Also, the recombining unit 202
Two openings (202a, 202b) are formed corresponding to the openings formed between the intake throttle valve 7 and the intake passage wall surface, but the present invention is not limited to this. Recombination part 2
02 may be at one location or may further include a third or more other recombination portion.

The EGR passage 18 extending from the exhaust passage 16 is connected to the branch passage 8 at a connection portion 801 between the branch portion 201 and the reconnection portion 202. Connection unit 80
Upstream of the orifice 22 is a turbulence promoting means.
Is installed. In the EGR gas diluting section D having such a configuration, a pipe forming the intake passage 2 to which the intake throttle valve 7 is attached and a pipe forming the branch passage 8 are integrally formed as an aluminum casting or the like.

With the EGR dilution section D configured as described above, first, the intake air a1 flows into the branch section 201 between the section a2 flowing directly through the intake passage 2 and the section a3 flowing into the branch passage 8. Divided into two. Therefore, a branch flow of the intake air flowing substantially along the intake passage 2 is formed in the branch passage 8. This diverted flow of intake air is then accelerated and depressurized at orifice 22 and creates turbulence in the wake. Orifice 22
, The EGR gas is sucked into the branch passage 8 and mixed into the intake air, and the turbulent energy promotes the dilution and mixing with the intake air.

The intake air thus mixed and EGR
The mixed gas a4 with the gas flows into the intake passage 2 from the recombining part 202, and the intake air a4 accelerated through the intake throttle valve 7.
Mix with 2. Therefore, regarding the EGR gas, it is mixed again with the intake air here, and the connection portion 801 is connected.
And the recombining unit 202 in two stages. Then, the turbulent energy also works in the recombination unit 202 to promote the dilution of the EGR gas.

As a problem in the EGR device, there has been a problem of insufficient mixing based on a difference in temperature and specific gravity between the EGR gas and the intake air. On the other hand, by mixing these gases in two stages as described above, E
The dilution of the GR gas is promoted, and the degree of mixing of the two is sufficiently increased. Therefore, the EGR rate of each cylinder can be made uniform.

Further, since the EGR gas dilution section D is integrally molded as a unit, it is compact and the layout in the engine room is easy. In addition, EGR
Since the gas flow volume hardly increases, the EGR responsiveness does not deteriorate, and the opening area of the intake system when fully opened is secured, so that the output does not deteriorate. In the dimensions indicated by the alphabets in FIG. 2, φA is the inner diameter of the intake passage 2, B is the distance from the branch portion 201 to the tip of the intake throttle valve 7,
φC is the inner diameter of the EGR passage 18, φD is the orifice opening diameter (corresponding to the restricting rate for a constant branch passage inner diameter), and E and F are the respective openings from the tip (opening) of the intake throttle valve 7. This is the distance to the coupling portions 202a and 202b.

These dimensions are determined by simulation and experiments based on the size and required performance of the engine 1. At the time of the determination, the maximum EGR amount is determined by the total cross-sectional area of the intake passage (φA + φD) and the cross-sectional area of the EGR passage (φ
C), the volumetric efficiency at full open is the total cross-sectional area of the intake passage (φA +
φD), and the degree of mixing of the EGR gas and the intake air (the dilution strength of the EGR gas) depends on the orifice opening diameter φD and the opening of the intake throttle valve 7 from the recombination parts 202a, 202.
The evaluation can be made based on the distances E and F to b.

Next, the operation of the ECU 101 will be described with reference to FIG.
This will be described with reference to the flowchart of FIG. S (step)
In step 1, various operation states such as an intake air amount Qair, an engine speed NE, and a water temperature Tw are read. In S2, it is determined whether or not the current operation state is in the EGR range. This determination is made as shown in the map of FIG.
E [rpm] and load (BMEP: net mean effective pressure [M
Pa]). If it is determined that the engine 1 is in the EGR range, the process proceeds to S3.

In S3, it is determined whether the EGR cut condition is satisfied based on the water temperature Tw and the like. If the operating state is not in the EGR range or the EGR cut condition is satisfied, the process proceeds to S4, where the EGR control valve 20 is closed to stop the EGR, and further in S5, the intake throttle valve 7 is fully opened.

On the other hand, if the EGR cut condition is not satisfied in S3, the process proceeds to S6, and the EGR control valve 20 is fully opened. In S7, the opening degree of the intake throttle valve 7 is adjusted as follows, and the routine returns. Here, the adjustment of the opening degree of the intake throttle valve 7 will be described with reference to FIG.

First, in the low-speed low-load operation region A, since the exhaust pressure is low, the differential pressure across the EGR control valve (hereinafter referred to as differential pressure)
δP decreases. Then, the intake negative pressure is formed by reducing the intake throttle valve 7 to obtain the required EGR amount. As the engine speed NE and the load BMEP increase from this point, the differential pressure δP increases. Therefore, the intake throttle valve 7 is opened to adjust the EGR amount.

In the middle rotation high load operation region B, the efficiency of the turbocharger 5 is improved, so that the differential pressure δP is reduced. Therefore, the intake throttle valve 7 is throttled again. In this operating state, since the intake air amount Qair is about half of the maximum output point, even if the intake throttle valve 7 is slightly reduced,
There is little deterioration in fuel efficiency. Further, in the high-speed operation region C, since the differential pressure δP increases again, the intake throttle valve 7 is opened.

In contrast to such a method, conventionally, the differential pressure δ
A general configuration is that if P is sufficient with respect to the required EGR amount, the EGR amount is controlled by adjusting the opening of the EGR control valve, and if the differential pressure δP is not sufficient, the intake throttle valve is throttled.
This will be described briefly (see FIG. 5). First, the intake passage opening area (in the present invention, the intake passage 2 and the branch passage 8
Athc, EGR passage opening area is Aegr, and intake throttle valve upstream pressure is Pin.
1. If the downstream pressure is Pin2 and the upstream pressure of the EGR control valve is Pexh, these parameters and the EGR amount Q
The relationship between egr and the intake air amount Qair is given by the following equation.

Qegr = Aegr√ (2 · ρ · (Pexh−Pin2)) (1) Qair = Athc√ (2 · ρ · (Pin1−Pin2)) (2) Normally (when the intake throttle valve is fully opened) The required EGR amount is obtained by adjusting the opening of the EGR control valve 20 to control the EGR passage opening area Aegr. Here, the differential pressure δP (= Pe
If xh-Pin2) is small, the intake throttle valve 7 is throttled to reduce the intake throttle valve downstream pressure Pin2.
Then, at the resulting differential pressure δP, the EGR
The opening of the control valve 20 is adjusted again.

As described above, in the conventional method, even if the EGR control valve 20 is fully opened, if the required EGR amount is still less than the required amount, the intake throttle valve 7 is actuated therefrom, so that a sufficient suction negative pressure is formed. It takes a considerable amount of time to respond, and the responsiveness includes a corresponding delay. In addition, since the two devices must be appropriately controlled during the EGR, the control logic is complicated.

According to the above method according to the present embodiment, E
Since the GR amount is controlled only by adjusting the opening of the intake throttle valve 7, there is no such delay, and the required EGR amount can be obtained in a necessary and sufficient operating state by such simple control. That is, even in the present embodiment, the EGR amount Qegr and the intake air amount Qair are determined based on the above equations (1) and (2).
First, the EGR control valve 20 is fixed to a fully open state. And
By adjusting the opening degree of the intake throttle valve 7, the downstream pressure P of the intake throttle valve is adjusted.
In2 is freely changed, and the EGR amount is controlled by the suction negative pressure thus positively formed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an EGR device of a diesel engine 1 according to an embodiment of the present invention.

FIG. 2 is a sectional view of an EGR gas dilution section D in the engine 1.

FIG. 3 is a flowchart of EGR control;

FIG. 4 is a graph showing an increase / decrease tendency of an EGR region and an EGR control valve differential pressure δP.

FIG. 5 is an explanatory diagram of an EGR amount calculation formula;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Intake passage 4 ... Air flow meter 5 ... Turbocharger 6 ... Intercooler 7 ... Intake throttle valve 8 ... Branch passage 11 ... Injector 12 ... Glow lamp 16 ... Exhaust passage 17 ... Exhaust after-treatment device 18 ... EGR passage 19 ... EGR cooler 20 ... EGR control valve 31 ... water temperature sensor 32 ... crank angle sensor 101 ... electronic control unit D ... EGR gas dilution section

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 9/02 F02D 9/02 S 351 351M 11/10 11/10 F 21/08 301 21/08 301A 41 / 02 360 41/02 360 41/04 360 41/04 360Z 43/00 301 43/00 301K 301N F-term (reference) 3G062 AA01 AA05 BA06 EB14 EC08 ED02 ED04 ED07 ED08 ED10 FA06 FA11 GA01 GA06 GA08 3G065 AA01 AA03A CA12 DA05 DA06 EA07 EA10 GA00 GA05 GA09 GA10 GA16 KA02 KA12 3G084 AA01 BA05 BA08 BA20 DA04 DA10 DA13 EB08 FA07 FA20 FA33 3G092 AA02 AA17 AA18 AB03 DC01 DC08 DG08 DG09 EC09 FA15 FA17 FA02 HA01Z HE03Z03 HA08 PA01Z PA11A PE01Z PE08Z

Claims (9)

[Claims] In an intake system, a branch passage that branches from an intake passage from a branch portion on an upstream side of an intake throttle valve and then rejoins with an intake passage at a rejoining portion on a downstream side of the intake throttle valve is formed. Forming a branch of the intake air substantially in line with the flow in the intake passage, connecting an exhaust recirculation passage extending from the exhaust passage to the branch passage at a connection between the branch portion and the recombination portion, and An exhaust gas recirculation gas, which is a part of the gas, is introduced from the connection portion to the branch passage through the exhaust gas recirculation passage, and a mixed gas of the exhaust gas recirculated gas flowing through the branch passage and the intake air is mixed with the recombined portion. An exhaust gas recirculation device for an internal combustion engine, wherein the exhaust gas is introduced into the intake passage from the intake air passage and mixed with the intake air through the intake throttle valve. 2. An exhaust gas recirculation device for an internal combustion engine for recirculating a part of exhaust gas from a combustion chamber to an intake passage, comprising: an intake throttle valve interposed in the intake passage; and a branch bypassing the intake throttle valve. A passage, which extends substantially along the intake passage after branching from the intake passage at a branch portion on the upstream side of the intake throttle valve, and is connected to the intake passage at a recombination portion on the downstream side of the intake throttle valve. A branch passage to be rejoined; an exhaust gas recirculation passage connected to the branch passage at a connection between the branch portion and the recombining portion; and an exhaust gas recirculation control valve interposed in the exhaust gas recirculation passage. Exhaust gas recirculation system for internal combustion engines. 3. The exhaust gas recirculation system for an internal combustion engine according to claim 1, wherein the branch passage is formed integrally with the intake passage adjacent to the intake passage. 4. A turbulence promoting means is provided in said branch passage upstream of said connecting portion.
3. The exhaust gas recirculation device for an internal combustion engine according to any one of 3. 5. An exhaust gas recirculation system for an internal combustion engine according to claim 4, wherein said turbulence promoting means is an orifice. 6. The internal combustion engine according to claim 1, wherein said recombination portion is formed in a turbulent flow development region of the intake air after passing through the intake throttle valve in the intake passage. Exhaust gas recirculation device for the engine. 7. The exhaust gas recirculation device for an internal combustion engine according to claim 1, wherein the exhaust gas recirculation passage extends from a downstream side of the exhaust aftertreatment device in the exhaust gas passage. 8. The exhaust gas of an internal combustion engine according to claim 1, wherein a cooling device is interposed between said exhaust gas recirculation passage and said exhaust gas recirculation control valve. Reflux device. 9. An exhaust gas recirculation amount is controlled by fully opening an exhaust gas recirculation control valve disposed in the exhaust gas recirculation passage and adjusting an opening degree of the intake throttle valve when the operating state is in an exhaust gas recirculation execution region. The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 8, wherein the exhaust gas recirculation device is controlled.