JPH07293356A - Exhaust reflux device for engine - Google Patents

Abstract

PURPOSE:To improve reliability of an intake system while possibly preventing generation of condensed water and secure reliability of an EGR valve. CONSTITUTION:In an EGR supply system 24, a catalyst converter 22 is arranged on an exhaust system, and an EGR valve 26 is provided between an exhaust system and an intake system. In a high load area of an engine, exhaust gas extracted from a downstream side of the catalyst converter 22 is introduced to the intake system. At least an EGR valve 26 among the EGR supply system 24 is arranged on a downstream side of running wind of a heat exchanger 15. In the case that EGR is started in the high load area, the EGR valve 26 is heated by the running blow increased in its temperature by heat exhange of the heat exchanger 15. Thus, even when the EGR gas shows a comparatively low temperature, temperature reduction which may be caused by cooling of the EGR supply system 24 including the EGR valve is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine exhaust gas recirculation system.

[0002]

2. Description of the Related Art In an engine, the temperature of exhaust gas may rise excessively under high load, which may impair the reliability of the exhaust system. The method of suppressing combustion heat was adopted. However, according to such a method, the fuel efficiency (so-called high-speed fuel efficiency) is deteriorated especially at high speed, which is not preferable.
As disclosed in Japanese Patent No. 187327, there has been proposed a technique of performing EGR in which exhaust gas is recirculated to an intake system when the engine has a high load and introducing exhaust gas of a relatively low temperature as this EGR gas.

When the exhaust gas is recirculated to the intake system as the EGR gas at the time of high load in this way, the exhaust gas is an inert gas, so that the engine intake amount as a whole is increased by the amount corresponding to the EGR gas amount. However, the exhaust gas amount also increases with this, but the combustion heat hardly changes, so the temperature of the exhaust gas relatively decreases, and the reliability of the exhaust system is ensured. Further, by using the relatively low temperature exhaust gas as the EGR gas, the rise in the intake air temperature due to the exhaust gas is reduced, the volume efficiency of intake air (fresh air) is improved accordingly, and the exhaust gas temperature is further reduced. Can be expected. The introduction / stop of such EGR gas is controlled by the EGR valve.

On the other hand, when the load is high, the EGR
In such a case, particularly when the high load operation is continued for a long time, the temperature of the EGR valve itself is increased due to the high temperature exhaust gas, and therefore the durability of the EGR valve itself is concerned. As one method for coping with such a situation, for example, as disclosed in Japanese Patent Laid-Open No. 5-240115, a high temperature E is generated during low load operation of the engine.
There is also known a technique in which the EGR gas having a relatively low temperature is introduced into one EGR valve and recirculated to the GR gas during high-load operation to suppress the temperature rise of the EGR valve and improve its reliability. .

[0005]

However, as in the former known example, when the exhaust gas of a relatively low temperature is recirculated to the intake system as EGR gas at the time of high engine load,
A new problem that corrosion of the intake system may occur may occur due to the following reasons.

That is, as a method of introducing the exhaust gas of a relatively low temperature at the time of high load, for example, the exhaust gas is taken out from the downstream side of the catalytic converter provided in the downstream portion of the exhaust passage or is radiated through a heat exchanger. Although various methods such as taking out the exhaust gas afterwards can be considered, in any case, the relatively low temperature exhaust gas is recirculated only at high load, and the recirculation of exhaust gas is stopped at low load. ing. Therefore, when the operating state of the engine shifts from the low load operating state to the high load operating state and EGR is started,
Since the EGR supply system including the EGR valve and the exhaust gas introduction passage radiates heat while the EGR is stopped and its temperature is lowered, a relatively low amount of exhaust gas is introduced into this EGR supply system as the operation shifts to high load operation. Then, the exhaust gas is cooled by the passage wall or the like until it reaches the EGR valve arranged near the engine, and the temperature thereof is lowered,
When it becomes 100 degrees Celsius or less, it is condensed and condensed water is generated.
This condensed water is also introduced into the intake system together with the exhaust gas. Here, if this condensed water is fresh water, there will be no serious problem, but the exhaust gas originally contains corrosive components such as sulfur. Therefore, when this exhaust gas is condensed, Will contain this corrosive component.

When condensed water containing such a corrosive component is introduced into the intake system, it may be introduced into the combustion chamber of the engine as it is. In particular, the intake system is equipped with a supercharger and an intercooler. In the case of an engine with a supercharger, since EGR gas is recirculated to the upstream side of the supercharger, condensed water enters the supercharger or the intercooler and accumulates there, causing corrosion of these. is there. Further, in the supercharger, although the clearance management is important for maintaining the performance thereof, the clearance is expanded due to corrosion and the performance is deteriorated. Further, in the intercooler, since the wall thickness of the heat transfer tube is extremely thin in order to secure heat transfer efficiency, perforation occurs in the heat transfer tube and the durability thereof is reduced.

On the other hand, as in the latter known example, one EGR valve is provided with a relatively low temperature exhaust gas under a high load and a high temperature exhaust gas under a low load depending on the engine operating conditions. However, if the duration of high load operation is relatively short, there is some effect, but if the high load operation is continued for a long time, the EGR valve will rise excessively. The durability is impaired, and the effect of improving the durability can hardly be expected.

In view of the above conventional problems, the present invention has been made in order to prevent the generation of condensed water as much as possible to improve the reliability of the intake system and to ensure the reliability of the EGR valve. Is.

[0010]

As a concrete means for solving such a problem, in the first invention of the present application, an exhaust system is provided with a catalytic converter, and an EGR valve is provided between the exhaust system and the intake system. In the exhaust gas recirculation device for an engine, which is provided with such an EGR supply system and introduces the exhaust gas taken out from the downstream side of the catalytic converter into the intake system in the high load region of the engine, the temperature rises as the engine operates. It is characterized in that at least the EGR valve of the EGR supply system is arranged on the downstream side of the traveling wind of the heat exchanger that is dissipated by the traveling wind.

In the second invention of the present application, an EGR supply system having an EGR valve is provided between the exhaust system and the intake system, and the exhaust gas taken out from the exhaust system when the exhaust gas temperature reaches a predetermined temperature or higher. In an exhaust gas recirculation system for an engine that is introduced into an intake system, at least the EGR of the EGR supply system is provided at a downstream side of a running wind of a heat exchanger that is heated by the operation of the engine and is radiated by running wind.
It features a valve.

According to the third invention of the present application, claim 1 or 2
In the exhaust gas recirculation system for an engine according to the item 1, the intake system is provided with a supercharger, the heat exchanger is an intercooler, and at least an EGR valve of the EGR supply system is arranged on a downstream side of a traveling wind of the intercooler. The exhaust gas supplied through the EGR valve is introduced upstream of the supercharger.

According to a fourth aspect of the present invention, in the exhaust gas recirculation system for an engine according to the third aspect, the intercooler is arranged above the transmission.

[0014]

With the above structure, the engine exhaust gas recirculation system of the present invention has the following unique functions and effects.

According to the exhaust gas recirculation system for an engine of the first invention of the present application, when the exhaust gas taken out from the downstream side of the catalytic converter is introduced into the intake system in the high load range, the engine is operated. At least the EG of the EGR supply system is provided on the downstream side of the running wind of the heat exchanger that is heated by the heat and is radiated by the running wind.
Since the R valve is arranged, the operating range of the engine shifts from the low load range to the high load range, and the E
When the recirculation of the GR gas is started, at least the EGR valve of the EGR supply system is warmed by the traveling wind whose temperature has been raised by heat exchange in the heat exchanger, so that the EGR valve is taken out from the downstream side of the catalytic converter. Even if the exhaust gas introduced therethrough to the intake system is at a relatively low temperature, the EGR supply system including the EGR valve prevents the exhaust gas from being cooled further and the exhaust gas has a temperature higher than a predetermined temperature. Will be maintained. Therefore, the generation of condensed water due to the decrease of the exhaust gas temperature to the condensation temperature or less is suppressed as much as possible, and the intake system is reliably prevented from being corroded by the introduction of condensed water containing a corrosive component.

When high load operation is continued for a long time,
During that time, since the EGR gas is continuously recirculated, the EGR supply system may be excessively heated, and the heat may impair the operational reliability of the EGR valve, which easily changes the EGR control characteristic. However, in this case, since at least the EGR valve of the EGR supply system is arranged on the downstream side of the traveling wind of the heat exchanger, it is cooled by the traveling wind to prevent the temperature of the traveling wind from rising above the temperature. . Therefore, the thermal effect on the operating characteristics of the EGR valve is small, the durability of the EGR valve itself is ensured, and the EGR control accuracy is maintained excellent.

According to the exhaust gas recirculation system for an engine of the second invention of the present application, the exhaust gas taken out from the exhaust system is introduced into the intake system when the exhaust gas temperature reaches or exceeds the predetermined temperature, Since at least the EGR valve of the EGR supply system is arranged on the downstream side of the running wind of the heat exchanger that is heated by the operation of the engine and is radiated by the running wind, the exhaust gas temperature reaches a predetermined temperature or higher. When the recirculation of the EGR gas via the EGR supply system is started, at least the EGR valve in the EGR supply system is warmed by the traveling wind heated by the heat exchange in the heat exchanger. Exhaust gas introduced therethrough to the intake system is prevented from being cooled by the EGR supply system including the EGR valve to further reduce the temperature, The above gas temperature will be maintained. Therefore, the generation of condensed water due to the decrease of the exhaust gas temperature to the condensation temperature or less is suppressed as much as possible, and the intake system is reliably prevented from being corroded by the introduction of condensed water containing a corrosive component.

When high load operation is continued for a long time,
During that time, since the EGR gas is continuously recirculated, the EGR supply system may be excessively heated, and the heat may impair the operational reliability of the EGR valve, which easily changes the EGR control characteristic. However, in this case, since at least the EGR valve of the EGR supply system is arranged on the downstream side of the traveling wind of the heat exchanger, the EGR valve and the like are cooled by the traveling wind and the temperature rises beyond the temperature of the traveling wind. There is nothing to do.
Therefore, the thermal effect on the operating characteristics of the EGR valve is small, the durability of the EGR valve itself is ensured, and the EGR control accuracy is maintained excellent.

According to the engine exhaust gas recirculation apparatus of the third invention of the present application, in the engine exhaust gas recirculation apparatus of the first invention or the second invention, a supercharger is provided in the intake system, and the heat The exchanger is used as an intercooler, and the EGR is provided on the downstream side of the running wind of the intercooler.
Since at least the EGR valve is arranged in the supply system and the exhaust gas supplied through the EGR valve is introduced to the upstream side of the supercharger, the basic operation described above or It is of course possible to obtain the effect, but especially because the EGR valve and the like are warmed up by the traveling wind that quickly heats up by heat exchange with the supercharged air that can be heated up in an extremely short time by supercharging. The warming up becomes quicker and more reliable, the generation of condensed water due to the decrease in the temperature of exhaust gas is suppressed as much as possible, and the corrosion of the intake system due to the corrosive components contained in the condensed water is reliably prevented. is there.

According to the engine exhaust gas recirculation system of the fourth invention of the present application, in the engine exhaust gas recirculation system of the third invention, the intercooler is arranged above the transmission. In addition to the same effects as described,
The upper position of the transmission has a space in terms of space because the transmission is lower in height than the engine and is continuously provided near the lower portion of the engine.
Therefore, it is easy to dispose the intercooler at a position above the transmission, and the workability in the installation work of the intercooler is improved accordingly. In addition, the fact that there is enough space means that the traveling air passing through the intercooler is better so that the traveling air that flows smoothly promotes the warm-up of the EGR valve and the like further, and It is possible to more reliably prevent the generation of condensed water due to the decrease in gas temperature.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An engine exhaust gas recirculation system according to the present invention will be specifically described below with reference to the accompanying drawings. Embodiments of the present invention applied to a V-type 6-cylinder automobile engine are shown in FIGS. The exhaust gas recirculation system according to FIG. 1 is shown, and in each of the drawings, reference numeral 1 is an engine having a first bank 1A and a second bank 1B, and the rear end side of the engine 1 is connected to the lower position thereof. The transmission 4 is attached. As shown in FIG. 1, the engine 1 is positioned with respect to a vehicle body (not shown) with the first bank 1A located near the front of the vehicle and the second bank 1B located near the rear of the vehicle. It is installed horizontally. In addition, a supercharger 5 composed of a resume compressor is arranged in the engine bank direction between the banks 1A and 1B of the engine 1 in the axial direction of the engine. The supercharger 5 is controlled to start and stop by controlling the operation of an electromagnetic clutch (not shown) by a control unit 34 described later.

A throttle valve body 9 having a built-in throttle valve is connected to an intake air inlet 5a located near one end of the supercharger 5, and a resonator 8 is connected to the upstream side of the throttle valve body 9. Further, an air cleaner 6 is connected to the upstream side of the resonator 8 via a connecting pipe 7.

On the other hand, a branch pipe 10 having a first branch pipe portion 10a and a second branch pipe portion 10b is connected to the intake / discharge port 5b located near the other end of the supercharger 5. Of the branch pipe portions 10a and 10b of the branch pipe 10, the first branch pipe portion 10a extends to the first bank 1A side through the front end side of the engine 1. Then, on the downstream side of the first branch pipe portion 10a, a first intercooler 11 is connected at a position above the first bank 1A with the cooling air inlet 11a directed toward the front of the vehicle body. Along with the first intercooler 11, the first surge tank 12 is provided with independent intake pipes 13, 13, 13 connected to the cylinders of the first bank 1A.
Are connected. In addition, a second intercooler arranged downstream of the second branch pipe portion 10b near the second bank 1B and above the transmission 4 with the cooling air inlet 15a directed toward the front of the vehicle body. 15 is connected to the second intercooler 1
A second surge tank 16 having independent intake pipes 17, 17, 17 connected to the respective cylinders of the second bank 1B is connected to the downstream side of 5. Further, the portion of the supercharger 5 near the intake inlet 5a and the surge tanks 1
2 and 16, air bypass pipes 20 and 2 for bypassing the supercharger 5 and the intercoolers 11 and 24.
1 are connected to each other. The air bypass pipes 20 and 21 are provided with an air bypass valve (not shown), and the operation of the air bypass valve is controlled by a control unit 34 described later.

In this embodiment, the intake system 2 is constructed from the air cleaner 6 to the engine 1 via the supercharger 5, the branch pipe 10, the intercoolers 11 and 24 and the surge tanks 12 and 13. There is. A first air duct 18 is connected to the cooling air inlet 11a of the first intercooler 11 and a second air duct 19 is connected to the cooling air inlet 15a of the second intercooler 15, and the respective air ducts 18, 19 upstream ends 18a, 19a
Both are open toward the front of the vehicle.

On the other hand, as shown in FIGS. 2 and 3, exhaust pipes 14b are respectively connected to the outer surfaces of the banks 1A and 1B of the engine 1 through exhaust manifolds 14a. Then, the exhaust pipes 14b, 14
On the downstream side, b merges into an exhaust merging pipe 14c, and the exhaust merging pipe 14c is provided with a catalytic converter 22. Further, an exhaust temperature sensor 33 that detects the exhaust gas temperature is provided in the exhaust pipe 13b. In this embodiment, the exhaust manifold 14a, the exhaust pipe 14b, and the exhaust merging pipe 14 are connected.
The exhaust system 3 is constituted by a passage leading to c.

Further, a first EGR supply system 23 and a second EGR supply system 24 described below are provided between the intake system 2 and the exhaust system 3.

The first EGR supply system 23 is provided to recirculate exhaust gas to the intake system 2 in the low load region of the engine to improve exhaust emission.
A first EGR valve 25 is provided between the introduction pipe 27 and the EGR supply pipe 28. And this 1E
The GR valve 25 is fixedly arranged at a position above the upper corner of the second bank 1B. Further, the other end of the EGR introducing pipe 27 whose one end is connected to the first EGR valve 25 has the other end of the exhaust manifold 14 on the second bank 1B side.
connected to a. Further, the first EGR valve 2
The other end of the EGR supply pipe 28, one end of which is connected to 5, is pulled out to above the supercharger 5, and then branched into two EGR branch pipes 29 and 30 to be respectively the first surge tanks. 12 and the second surge tank 16 are connected.

On the other hand, the second EGR supply system 24 is equivalent to the EGR supply system in the claims.
Only in the high engine load range, the exhaust gas is recirculated to the intake system 2 to lower the temperature of the exhaust gas so that the exhaust system 3
To ensure the reliability of. This second EGR
The supply system 24 includes the second EGR valve 26 and the EGR introduction pipe 3
1 and an EGR supply pipe 32. Then, the second EGR valve 26 is fixedly arranged so as to be located immediately behind the cooling air outlet 15b of the second intercooler 15. Further, the other end of the EGR introducing pipe 31 whose one end is connected to the second EGR valve 26 is
As shown in, the exhaust gas confluent pipe 14c is connected to the downstream side of the catalytic converter 22. Further, the EGR whose one end is connected to the second EGR valve 26.
As shown in FIG. 1, the supply pipe 32 is connected to a portion of the intake port 5a of the supercharger 5 (that is, the upstream side of the supercharger 5). The first EGR valve 25 and the second EGR valve 26 are both the control unit 34 described later.
Its operation is controlled by.

The control unit 34 performs supercharging control and EGR control, and employs engine load and exhaust gas temperature as control elements (exhaust gas temperature will be described later). Is adopted for EGR control in other embodiments).

First, regarding supercharging control, this supercharging control is performed by controlling the operation of the electromagnetic clutch and the air bypass valve based on the engine load. Specifically, in the low load region of the engine, the electromagnetic clutch is disengaged to stop the supercharger 5, the air bypass valve is opened, and intake air is bypassed between the supercharger 5 and the intercoolers 11 and 15. The air bypass pipes 20 and 2
It is supplied to the engine from 1 by natural aspiration. On the other hand, in the high-load range of the engine, the electromagnetic clutch is connected to drive the supercharger 5, and the air bypass valve is closed to allow the supercharged air supercharged by the supercharger 5. Is supplied to the engine.

Next, regarding EGR control, this EGR control is performed based on the engine load. In particular,
In the low load region of the engine, the first EGR valve 25
Only the second EGR valve 26 is closed. Therefore,
In this low load range, high temperature exhaust gas is recirculated from the first EGR supply system 23 to the intake system 2 as EGR gas.
As a result, combustion in the engine is suppressed and exhaust emission is improved.

On the other hand, in the high load region of the engine, only the second EGR valve 26 is opened and the first EGR valve 25 is closed. Therefore, in this high load region, the exhaust gas downstream of the catalytic converter 22 (that is, the relatively low temperature exhaust gas whose temperature has decreased due to passing through the catalytic converter 22) flows through the second EGR supply system 24. It is returned to the upstream side of the supercharger 5. Therefore, in this high load region, the exhaust gas temperature is lowered by the introduction of the EGR gas into the intake system 2, so that the reliability of the exhaust system 3 is ensured.

By the way, when the EGR gas is recirculated from the second EGR supply system 24 only in the high load region of the engine and is stopped in the low load region,
This EGR gas is the exhaust gas at a relatively low temperature (usually about 250 ° C.) taken out from the downstream of the catalytic converter 22, and the exhaust gas flows through the second EGR supply system 24 in a long and low load region. Since the temperature is low (about room temperature), the exhaust gas temperature, which was about 250 ° C., reached the vicinity of the second EGR valve 26 when no warm-up action was exerted on the second EGR supply system 24. At times, the temperature drops to about 60 ° C., and the exhaust gas condenses to generate condensed water containing a corrosive component such as sulfur. When this condensed water is introduced into the intake system 2, for example, in the supercharger 5, the supercharging performance is deteriorated or its durability is impaired due to corrosion, and the second intercooler 15 is also used.
As described above, in this case, corrosion perforation causes a disadvantage such as a decrease in durability.

However, in the embodiment,
Since the second EGR valve 26 of the second EGR supply system 24 is arranged on the rear side of the cooling air outlet 15b of the second intercooler 15, the generation of condensed water is suppressed as much as possible, and the above-mentioned inconvenience occurs. It is something that can be prevented.

That is, since the supercharger 5 composed of the resuming compressor is a compression type supercharger, the supercharger 5 is
The temperature of the intake air discharged from is increased to about 160 ° C. When this high-temperature intake air is guided to the second intercooler 15, the intake air temperature is slightly lowered due to heat radiation to the passage from the vicinity of the discharge port of the supercharger 5 to the second intercooler 15.
The temperature is still high at about 40 to 150 ° C.
When this high-temperature intake air passes through the second intercooler 15, it exchanges heat with the traveling wind of the vehicle introduced through the second air duct 19. The traveling wind exchanges heat with this intake air, and the traveling air of the second intercooler 15 is exchanged. 100 ° C on the outlet side
It rises instantly to a level, and over time 12
It rises to about 0 ° C. Therefore, since the high-temperature running wind flows near the second EGR valve 26, the wall temperature of the exhaust gas passage of the second EGR valve 26 becomes 90%.
The temperature can be raised up to about 100 ° C. Therefore, the exhaust gas taken out from the exhaust system 3 side has a wall temperature of 90 to 100 ° C. even if the temperature of the exhaust gas decreases to about 60 ° C. before reaching the second EGR valve 26.
Therefore, condensation does not occur and condensed water is not generated. Further, for example, even if condensed water is generated by condensing before reaching the second EGR valve 26, this condensed water will be vaporized when reaching the second EGR valve 26. Therefore, the inconvenience caused by the introduction of condensed water as described above can be avoided.

On the other hand, when the high load operation in which such EGR is performed continues for a long time, the second EGR valve 26 gradually rises to its heat resistance limit temperature (about 200 ° C.) due to the circulation of EGR gas, and the reliability of its operation or As described above, the durability may be impaired. However, in this embodiment, as described above, the second EGR
The valve 26 is the cooling air outlet 15 of the second intercooler 15.
The second EGR valve 26 is disposed near b and is exposed to the running wind after passing through the second intercooler 15. Therefore, the second EGR valve 26 is cooled by the running wind, contrary to the transition to the high load operation. Temperature, that is, about 120 ° C.

As another embodiment, instead of introducing the EGR gas into the intake system 2 via the second EGR supply system 24 in accordance with the engine load as in the above embodiment,
It is also possible to do this based on the exhaust gas temperature. That is, when the exhaust gas temperature detected by the exhaust temperature sensor 33 reaches a temperature allowed by the reliability of the exhaust system 3,
The second EGR valve 26 is opened to start EGR. In this case as well, it is needless to say that the same operational effects as those of the above-mentioned embodiment can be obtained.

Further, although the second EGR valve 26 is arranged on the rear side of the second intercooler 15 in the above embodiment (that is, the heat radiation of the intake air in the second intercooler 15 is used), the heat of the invention of the present application is used. The exchanger is not limited to such an intercooler, and it goes without saying that a radiator, an air-cooled oil intercooler, or the like can be used, for example.

[Brief description of drawings]

FIG. 1 is a plan view of an engine equipped with an exhaust gas recirculation device according to an embodiment of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a view on arrow III-III in FIG.

[Explanation of symbols]

1 is an engine, 2 is an intake system, 3 is an exhaust system, 4 is a transmission, 5 is a supercharger, 6 is an air cleaner, 7 is a connecting pipe, 8 is a resonator, 9 is a throttle valve body, 1
0 is a branch pipe, 11 is a first intercooler, 12 is a first surge tank, 13 is an independent intake pipe, 14 is an exhaust manifold, 15 is a second intercooler, 16 is a second surge tank, 17 is an independent intake pipe, 18 is a first air duct, 19 is a second air duct, 20 is an air bypass pipe, 21 is an air bypass pipe, 22 is a catalytic converter, 23 is a first EGR supply system, 24 is a second EGR supply system, 25 is a first EGR valve, 26 Is a second EGR valve, 27 is an EGR introduction pipe, 2
8 EGR supply pipe, 29 EGR branch pipe, 30 EGR
Branch pipe, 31 EGR introduction pipe, 32 EGR supply pipe, 3
3 is an exhaust gas temperature sensor, and 34 is a control unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location F02B 67/00 F (72) Inventor Hirohide Abe 3-1, Shinchi Fuchu-cho, Aki-gun, Hiroshima Mazda Stock In-house (72) Inventor Tomomi Oshima 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd.

Claims (4)

[Claims] 1. An EGR having an exhaust system provided with a catalytic converter and an EGR valve provided between the exhaust system and the intake system.
An exhaust gas recirculation device for an engine, which is provided with a supply system and introduces the exhaust gas taken out from the downstream side of the catalytic converter into the intake system in a high load region of the engine. The EGR is provided on the downstream side of the traveling wind of the heat exchanger that is dissipated by the traveling wind.
An exhaust gas recirculation device for an engine, wherein at least the EGR valve of a supply system is arranged. 2. An EGR supply system having an EGR valve is provided between the exhaust system and the intake system, and when the exhaust gas temperature reaches a predetermined temperature or higher, the exhaust gas taken out from the exhaust system is introduced into the intake system. In the exhaust gas recirculation device for an engine, the EGR is provided on the downstream side of the running wind of the heat exchanger that is heated by the operation of the engine and is radiated by the running wind.
An exhaust gas recirculation device for an engine, wherein at least the EGR valve of a supply system is arranged. 3. The intake system according to claim 1 or 2, wherein the intake system is provided with a supercharger, the heat exchanger is an intercooler, and at least an EGR valve of the EGR supply system is provided downstream of the intercooler in a traveling wind. And an exhaust gas supplied through the EGR valve is introduced upstream of the supercharger. 4. The exhaust gas recirculation device for an engine according to claim 3, wherein the intercooler is arranged above the transmission.