JP2017186946A - Exhaust gas recirculation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas recirculation device for a multi-cylinder internal combustion engine capable of maintaining an air-fuel ratio of a specific cylinder for generating exhaust gas recirculated to an intake side at an air-fuel ratio optimizing fuel economy.SOLUTION: An exhaust gas recirculation device 1 for recirculating part of exhaust gas discharged from a multi-cylinder internal combustion engine 2 to an intake side includes: a main intake passage 10a for introducing air to the multi-cylinder internal combustion engine 2; a branch passage 24a communicated with the main intake passage 10a and introducing air to a specific cylinder #4 out of a plurality of cylinders; branch passages 21a, 22a, 23a communicated with the main intake passage 10a and introducing air to cylinders #1, #2, #3 excluding the specific cylinder #4; an exhaust gas recirculation passage 40a for recirculating a total amount of exhaust gas discharged from the specific cylinder #4 to the main intake passage 10a upstream of an intake manifold 20; and a control valve 25 for controlling the amount of air introduced to the specific cylinder #4. The control valve 25 is provided in the branch passage 24a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust gas recirculation device for an internal combustion engine.

  As a conventional exhaust gas recirculation device, one having a structure in which only exhaust gas generated in a single cylinder called a dispenser cylinder among a plurality of cylinders of an internal combustion engine is recirculated into an intake passage (for example, Patent Document 1).

  In the exhaust gas recirculation device described in Patent Document 1, the exhaust gas recirculation ratio is adjusted by increasing or decreasing the amount of fuel injected into the combustion space of the dispenser cylinder (hereinafter referred to as “fuel injection amount”).

JP-T-2003-506619

  However, in the exhaust gas recirculation device described in Patent Document 1, the fuel injection amount of the dispenser cylinder is increased or decreased in order to adjust the exhaust gas recirculation ratio, so that the air-fuel ratio in the dispenser cylinder changes. For this reason, the air-fuel ratio in the dispenser cylinder cannot be maintained at the air-fuel ratio at which the fuel efficiency is optimal.

  The present invention has been made in view of the above-described circumstances, and can maintain the air-fuel ratio in a specific cylinder that generates exhaust gas recirculated to the intake side at an air-fuel ratio that optimizes fuel efficiency. An object of the present invention is to provide an exhaust gas recirculation device for a cylinder internal combustion engine.

  In order to achieve the above object, the present invention provides an exhaust gas recirculation device that recirculates a part of exhaust gas discharged from a multi-cylinder internal combustion engine having a plurality of cylinders to the intake side, wherein air is supplied to the multi-cylinder internal combustion engine. A main intake passage to be introduced, a first intake passage that communicates with the main intake passage and introduces air into a specific cylinder among the plurality of cylinders, and a main intake passage that communicates with the main intake passage. A second intake passage for introducing air into the cylinder and a total amount of exhaust gas exhausted from the specific cylinder into the first intake passage and the main intake passage upstream of the second intake passage. An exhaust gas recirculation passage for recirculation and a control valve for adjusting the amount of air introduced into the specific cylinder are provided, and the control valve is provided in the first intake passage.

  According to the present invention, there is provided an exhaust gas recirculation device for a multi-cylinder internal combustion engine that can maintain an air fuel ratio in a specific cylinder that generates exhaust gas recirculated to the intake side at an air fuel ratio that optimizes fuel efficiency. Can do.

FIG. 1 is a schematic configuration diagram of an exhaust gas recirculation apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing a first modification of the exhaust gas recirculation apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic configuration diagram showing a second modification of the exhaust gas recirculation apparatus according to the first embodiment of the present invention. FIG. 4 is a schematic configuration diagram of an exhaust gas recirculation apparatus according to the second embodiment of the present invention. FIG. 5 is a schematic configuration diagram showing a first modification of the exhaust gas recirculation apparatus according to the second embodiment of the present invention. FIG. 6 is a schematic configuration diagram showing a second modification of the exhaust gas recirculation apparatus according to the second embodiment of the present invention. FIG. 7 is a schematic configuration diagram of an exhaust gas recirculation apparatus according to the third embodiment of the present invention. FIG. 8 is a schematic configuration diagram of an exhaust gas recirculation apparatus according to the fourth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
(First embodiment)

  As shown in FIG. 1, an exhaust gas recirculation apparatus 1 according to the present embodiment is mounted on a vehicle having a multi-cylinder internal combustion engine 2, and a part of exhaust gas discharged from the multi-cylinder internal combustion engine 2 is recirculated to the intake side. It is something to be made. The multi-cylinder internal combustion engine 2 is composed of, for example, an in-line 4-cylinder gasoline engine having four cylinders # 1, # 2, # 3, and # 4.

  The multi-cylinder internal combustion engine 2 has a fuel injection valve and an ignition device (not shown). The fuel injection valve and the ignition device are provided for each of the four cylinders # 1, # 2, # 3, and # 4. The intake ports of the four cylinders # 1, # 2, # 3, and # 4 communicate with an intake manifold 20 described later.

  Of the four cylinders, the exhaust ports of cylinders # 1, # 2, and # 3 communicate with an exhaust manifold 30 described later. An exhaust port of a specific cylinder # 4 among the four cylinders communicates with an exhaust gas recirculation passage 40a described later.

  As described above, in the present embodiment, the exhaust ports of the cylinders # 1, # 2, and # 3 are not in communication with the exhaust gas recirculation passage 40a, and only the exhaust ports of the specific cylinder # 4 are connected to the exhaust gas recirculation passage 40a. Communicate. Therefore, the specific cylinder # 4 is configured as an EGR gas generating cylinder for returning the entire amount of exhaust gas generated in the cylinder # 4 to the intake side as EGR gas.

  The exhaust gas recirculation device 1 includes an intake pipe 10, an intake manifold 20, an exhaust manifold 30, and an exhaust gas recirculation pipe 40. Inside the intake pipe 10, a main intake passage 10a for introducing air into the multi-cylinder internal combustion engine 2 is formed.

  The main intake passage 10a is provided with an air cleaner 15 for purifying the intake air and a throttle valve 16 for adjusting the amount of air introduced into the multi-cylinder internal combustion engine 2. The throttle valve 16 is disposed downstream of the air cleaner 15.

  Upstream refers to the upstream side with respect to the direction of air flow. On the other hand, the downstream means the downstream side with respect to the air flow direction. Moreover, in this Embodiment, the one end in each piping and channel | path refers to the edge part of the upstream of the said piping and channel | path. On the other hand, the other end in each pipe and passage refers to the downstream end of the pipe and passage.

  The intake manifold 20 communicates the main intake passage 10a with each of the four cylinders # 1, # 2, # 3, and # 4. The intake manifold 20 distributes the air introduced from the main intake passage 10a to the four cylinders # 1, # 2, # 3, # 4, and includes four branch pipes 21, 22, 23, 24.

  The intake manifold 20 is connected to the intake pipe 10 by connecting the upstream sides of the four branch pipes 21, 22, 23, and 24. The downstream sides of the branch pipes 21, 22, 23, and 24 are connected to the cylinders # 1, # 2, # 3, and # 4, respectively.

  Branch passages 21a, 22a, 23a, and 24a are formed inside the branch pipes 21, 22, 23, and 24, respectively. The upstream side of the branch passages 21a, 22a, 23a, 24a communicates with the main intake passage 10a. The downstream sides of the branch passages 21a, 22a, 23a, and 24a communicate with the intake ports of the cylinders # 1, # 2, # 3, and # 4.

  Of the four branch passages, the branch passage 24a is a passage for introducing air into a specific cylinder # 4 of the four cylinders. The branch passage 24a in the present embodiment constitutes a first intake passage.

  The branch passages 21a, 22a, and 23a are passages for introducing air into the cylinders other than the specific cylinder # 4 among the four cylinders, that is, the cylinders # 1, # 2, and # 3. The branch passages 21a, 22a, and 23a in the present embodiment constitute a second intake passage.

  A control valve 25 is provided in the intake manifold 20. Specifically, the control valve 25 is provided in the branch passage 24a. The adjustment valve 25 adjusts the amount of air introduced from the main intake passage 10a to the specific cylinder # 4 via the branch passage 24a.

  The exhaust manifold 30 collects exhaust gas discharged from each of the three cylinders # 1, # 2, and # 3 and discharges the exhaust gas to the exhaust passage 50a in the exhaust pipe 50. The three exhaust cylinders # 1 and # 2 , # 3, three branch pipes 31, 32, 33 are provided.

  The upstream sides of the three branch pipes 31, 32, and 33 are connected to the cylinders # 1, # 2, and # 3, respectively. The downstream sides of the branch pipes 31, 32, 33 are coupled to each other and connected to the exhaust pipe 50.

  Branch passages 31a, 32a, and 33a are formed in the branch pipes 31, 32, and 33, respectively. The upstream side of the branch passages 31a, 32a, 33a communicates with the exhaust ports of the cylinders # 1, # 2, # 3. The downstream side of the branch passages 31a, 32a, 33a communicates with the discharge passage 50a.

  The exhaust passage 50a is a passage that exhausts exhaust gas discharged from cylinders other than the specific cylinder # 4, that is, cylinders # 1, # 2, and # 3. A catalyst 51 for purifying exhaust gas discharged from the cylinders # 1, # 2, and # 3 is provided in the discharge passage 50a. The branch passages 31a, 32a, 33a and the discharge passage 50a in the present embodiment constitute an exhaust passage.

  The exhaust gas recirculation pipe 40 has one end connected to the specific cylinder # 4 and the other end connected to the intake pipe 10. An exhaust gas recirculation passage 40 a is formed inside the exhaust gas recirculation pipe 40. One end of the exhaust gas recirculation passage 40a communicates with a specific cylinder # 4. The other end of the exhaust gas recirculation passage 40 a communicates with the main intake passage 10 a upstream of the intake manifold 20. More specifically, the other end of the exhaust gas recirculation passage 40 a communicates with the main intake passage 10 a upstream of the throttle valve 16.

  Therefore, the exhaust gas recirculation passage 40a is a passage that recirculates the exhaust gas exhausted from the specific cylinder # 4 to the main intake air passage 10a upstream of the intake manifold 20 as EGR gas. An EGR cooler 41 is provided in the exhaust gas recirculation passage 40a. The EGR cooler 41 cools the exhaust gas recirculated in the exhaust gas recirculation passage 40a from the specific cylinder # 4 toward the main intake air passage 10a.

  A vehicle equipped with the exhaust gas recirculation device 1 according to the present embodiment includes an ECU 100. The ECU 100 includes, for example, a microcomputer including a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and performs signal processing according to a program stored in advance in the ROM. . Various control constants and various maps are stored in advance in the ROM.

  The ECU 100 is connected to various devices and various sensors such as the throttle valve 16, the control valve 25, the fuel injection valve, and the ignition device described above. The throttle valve 16 and the adjustment valve 25 are configured by electronically controlled valves, and the opening degree thereof is adjusted according to a command signal from the ECU 100.

  In the present embodiment, the amount of air introduced into the specific cylinder # 4 is adjusted by adjusting the opening of the control valve 25 by the ECU 100. As a result, the amount of exhaust gas generated in the specific cylinder # 4 changes. As a result, the amount of exhaust gas recirculated to the intake side as EGR gas is changed.

  For this reason, in this Embodiment, the EGR rate can be made variable by adjusting the opening degree of the control valve 25. The EGR rate indicates the ratio of burned gas contained in the air-fuel mixture introduced into the cylinder.

  In the present embodiment, the air-fuel ratio in the specific cylinder # 4 as the EGR gas generating cylinder is controlled to be different from the other cylinders # 1, # 2, and # 3. Specifically, the air-fuel ratio of the other cylinders # 1, # 2, and # 3 is controlled to the stoichiometric air-fuel ratio, while the air-fuel ratio of the specific cylinder # 4 is set to an air-fuel ratio at which the fuel efficiency is optimal. Be controlled. Thereby, the fuel injection amount in the specific cylinder # 4 is reduced.

  The air / fuel ratio at which the fuel efficiency is optimal is an air / fuel ratio leaner than the stoichiometric air / fuel ratio. The ECU 100 can control the fuel injection amount in the specific cylinder # 4 to control the air / fuel ratio of the specific cylinder # 4 to an air / fuel ratio at which the fuel efficiency is optimal. As a result, the air-fuel ratio of the specific cylinder # 4 is maintained at the air-fuel ratio at which the fuel efficiency is optimal, without being influenced by the air-fuel ratio of the other cylinders # 1, # 2, and # 3. The relationship between the air-fuel ratio at which the fuel efficiency is optimal and the fuel injection amount in the specific cylinder # 4 is obtained experimentally in advance and is stored in the ROM of the ECU 100 as a map.

  As described above, the exhaust gas recirculation apparatus 1 according to the present embodiment has a configuration in which the control valve 25 is provided in the branch passage 24a that introduces air into the specific cylinder # 4 as the EGR gas generation cylinder. Further, the exhaust gas recirculation apparatus 1 according to the present embodiment is configured such that the entire amount of exhaust gas discharged from the specific cylinder # 4 is recirculated to the main intake passage 10a through the exhaust gas recirculation passage 40a as EGR gas. . Further, the exhaust gas recirculation passage 40 a is independent of the exhaust manifold 30.

  For this reason, in the exhaust gas recirculation apparatus 1 according to the present embodiment, the exhaust gas of the specific cylinder # 4 does not flow into the catalyst 51 via the exhaust manifold 30, so that the other cylinders # 1, # 2, # The air-fuel ratio of the specific cylinder # 4 can be independently controlled without being influenced by the air-fuel ratio of 3. Therefore, the air-fuel ratio of the specific cylinder # 4 can be controlled to the air-fuel ratio at which the fuel efficiency is optimal. Further, since the exhaust gas of the specific cylinder # 4 does not directly flow into the catalyst 51, the emission is not deteriorated.

  Further, the exhaust gas recirculation apparatus 1 according to the present embodiment controls the fuel injection amount in the specific cylinder # 4 according to the opening degree of the control valve 25, so that the fuel efficiency is optimal for the air-fuel ratio of the specific cylinder # 4. The air / fuel ratio can be maintained.

  Furthermore, since the exhaust gas recirculation apparatus 1 according to the present embodiment adjusts the amount of air introduced into the specific cylinder # 4 by the adjustment valve 25, the EGR rate is reduced as compared with the case where only the fuel injection amount is adjusted. It can be changed greatly. That is, the adjustment range of the EGR rate can be increased.

(First modification)
In the present embodiment, the branch passage 24a is used as the first intake passage for introducing air from the main intake passage 10a to the specific cylinder # 4. However, as shown in FIG. An independently provided introduction passage 26a may be used as the first intake passage.

  Specifically, the introduction pipe 26 in the first modification has one end connected to the intake pipe 10 and the other end connected to a specific cylinder # 4. Inside the introduction pipe 26, an introduction passage 26a as a first intake passage is formed.

  The introduction passage 26 a communicates with the main intake passage 10 a on the upstream side of the throttle valve 16. A control valve 25 is provided in the introduction passage 26a.

(Second modification)
In the present embodiment, the exhaust gas recirculation passage 40a communicates with the main intake passage 10a on the upstream side of the throttle valve 16, but the exhaust gas recirculation passage 40a is connected to the main intake air on the downstream side of the throttle valve 16 as shown in FIG. You may communicate with the channel | path 10a.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.

  In the case of the configuration in which the exhaust gas of the specific cylinder # 4 is recirculated to the upstream side of the branch passage 24a or the introduction passage 26a via the exhaust recirculation passage 40a as in the first embodiment described above, the branch passage 24a or introduction EGR gas is mixed in the air introduced into the specific cylinder # 4 through the passage 26a.

  In this case, the combustion speed in the specific cylinder # 4 is slower than when fresh air that does not contain EGR gas is introduced into the specific cylinder # 4. For this reason, combustion in the specific cylinder # 4 may become unstable, and it may be difficult to maintain the air-fuel ratio of the specific cylinder # 4 at the air-fuel ratio at which the fuel efficiency is optimal.

  Therefore, in the present embodiment, an introduction passage 224a for introducing air from the main intake passage 10a to the specific cylinder # 4 is provided separately from the intake manifold 20, and fresh air that does not contain EGR gas is supplied to the specific cylinder #. 4 was adopted. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 4, the exhaust gas recirculation apparatus 201 according to the present embodiment includes an introduction pipe 224 and an exhaust gas recirculation pipe 240. The introduction pipe 224 has one end connected to the intake pipe 10 and the other end connected to a specific cylinder # 4.

  Inside the introduction pipe 224, an introduction passage 224a as a first intake passage is formed. The introduction passage 224a communicates with the main intake passage 10a on the upstream side of an exhaust gas recirculation passage 240a described later. A control valve 25 is provided in the introduction passage 224a.

  The exhaust gas recirculation pipe 240 has one end connected to the specific cylinder # 4 and the other end connected to the intake pipe 10. An exhaust gas recirculation passage 240 a is formed inside the exhaust gas recirculation pipe 240. One end of the exhaust gas recirculation passage 240a communicates with a specific cylinder # 4. The other end of the exhaust gas recirculation passage 240 a communicates with the main intake passage 10 a on the downstream side of the introduction passage 224 a and the upstream side of the intake manifold 20. Therefore, the exhaust gas recirculation passage 240a recirculates to the main intake passage 10a downstream of the introduction passage 224a and upstream of the intake manifold 20 by using the total amount of exhaust gas discharged from the specific cylinder # 4 as EGR gas. .

  As described above, the exhaust gas recirculation apparatus 201 according to the present embodiment has a configuration in which the control valve 25 is provided in the introduction passage 224a that introduces air into the specific cylinder # 4 as the EGR gas generation cylinder. Further, the exhaust gas recirculation apparatus 201 according to the present embodiment is configured such that the entire amount of exhaust gas discharged from the specific cylinder # 4 is recirculated to the main intake passage 10a through the exhaust gas recirculation passage 240a as EGR gas. . Further, the exhaust gas recirculation passage 240 a is independent of the exhaust manifold 30.

  For this reason, in the exhaust gas recirculation apparatus 201 according to the present embodiment, the exhaust gas of the specific cylinder # 4 does not flow into the catalyst 51 via the exhaust manifold 30, so that the other cylinders # 1, # 2, # The air-fuel ratio of the specific cylinder # 4 can be independently controlled without being influenced by the air-fuel ratio of 3. Therefore, the air-fuel ratio of the specific cylinder # 4 can be controlled to the air-fuel ratio at which the fuel efficiency is optimal. Further, since the exhaust gas of the specific cylinder # 4 does not directly flow into the catalyst 51, the emission is not deteriorated.

  Further, the exhaust gas recirculation apparatus 201 according to the present embodiment controls the fuel injection amount in the specific cylinder # 4 according to the opening degree of the control valve 25, so that the fuel efficiency is optimal for the air-fuel ratio of the specific cylinder # 4. The air / fuel ratio can be maintained.

  Further, since the exhaust gas recirculation apparatus 201 according to the present embodiment adjusts the amount of air introduced into the specific cylinder # 4 by the adjustment valve 25, the EGR rate is reduced as compared with the case where only the fuel injection amount is adjusted. It can be changed greatly. That is, the adjustment range of the EGR rate can be increased.

  Further, in the exhaust gas recirculation apparatus 201 according to the present embodiment, since the introduction passage 224a communicates with the main intake passage 10a on the upstream side of the exhaust gas recirculation passage 240a, fresh air that does not contain EGR gas is supplied to a specific cylinder. # 4 can be introduced. Thereby, the combustion speed in the specific cylinder # 4 can be improved. As a result, combustion in the specific cylinder # 4 can be stabilized, and the air-fuel ratio of the specific cylinder # 4 can be maintained at the air-fuel ratio at which the fuel efficiency is optimal.

(First modification)
In the present embodiment, the introduction passage 224a communicates with the main intake passage 10a on the downstream side of the air cleaner 15, but the introduction passage 226a communicates with the main intake passage 10a in the air cleaner 15 as shown in FIG. It may be.

  Specifically, the introduction pipe 226 in the first modification has one end connected to the air cleaner 15 and the other end connected to a specific cylinder # 4. Inside the introduction pipe 226, an introduction passage 226a as a first intake passage is formed.

  The introduction passage 226 a communicates with the main intake passage 10 a in the air cleaner 15. A control valve 25 is provided in the introduction passage 226a.

(Second modification)
In the present embodiment, the exhaust gas recirculation passage 240a communicates with the main intake passage 10a on the upstream side of the throttle valve 16, but the exhaust gas recirculation passage 240a is on the main intake side on the downstream side of the throttle valve 16 as shown in FIG. You may communicate with the channel | path 10a.

(Third embodiment)
Next, a third embodiment of the present invention will be described.

  This embodiment is different from the first embodiment in that an exhaust gas recirculation valve 42 and a communication valve 43 are provided. Accordingly, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 7, the exhaust gas recirculation device 301 according to the present embodiment includes an exhaust gas recirculation valve 42 and a communication valve 43. The exhaust gas recirculation valve 42 is provided in the exhaust gas recirculation passage 40 a on the downstream side of the EGR cooler 41. The exhaust gas recirculation valve 42 is constituted by an electronically controlled valve, and the opening degree thereof is adjusted according to a command signal from the ECU 100.

  In the present embodiment, the exhaust manifold 30 and the exhaust gas recirculation passage 40a communicate with each other, and a communication valve 43 is provided at the communication portion. The communication valve 43 adjusts the flow rate of the exhaust gas discharged from the exhaust gas recirculation passage 40a to the exhaust manifold 30. The communication valve 43 is configured by an electronically controlled valve, and the opening degree thereof is adjusted according to a command signal from the ECU 100.

  In the present embodiment, the flow rate of the EGR gas recirculated from the specific cylinder # 4 to the main intake passage 10a can be adjusted by adjusting the opening degrees of the exhaust gas recirculation valve 42 and the communication valve 43 by the ECU 100. .

  For example, when the total amount of exhaust gas of the specific cylinder # 4 is recirculated to the main intake passage 10a as EGR gas (EGR execution state), the communication valve 43 may be fully closed and the exhaust recirculation valve 42 may be opened. On the other hand, when the entire exhaust gas of the specific cylinder # 4 is not recirculated to the main intake passage 10a but is discharged to the discharge passage 50a (EGR stopped state), the exhaust recirculation valve 42 is fully closed and communicated. The valve 43 may be opened.

  As described above, the exhaust gas recirculation apparatus 301 according to the present embodiment has a configuration in which the control valve 25 is provided in the branch passage 24a that introduces air into the specific cylinder # 4 as the EGR gas generation cylinder. Further, the exhaust gas recirculation apparatus 301 according to the present embodiment adjusts the opening degree of the exhaust gas recirculation valve 42 and the communication valve 43 so that the total amount of exhaust gas discharged from the specific cylinder # 4 is used as the EGR gas. 10a can be refluxed. Further, the exhaust gas recirculation passage 40 a is independent of the exhaust manifold 30.

  For this reason, in the exhaust gas recirculation apparatus 301 according to the present embodiment, the exhaust gas of the specific cylinder # 4 does not flow into the catalyst 51 via the exhaust manifold 30 in the EGR execution state. The air-fuel ratio of the specific cylinder # 4 can be independently controlled without being influenced by the air-fuel ratio of # 2, # 3. Therefore, in the EGR execution state, the air-fuel ratio of the specific cylinder # 4 can be controlled to the air-fuel ratio at which the fuel efficiency is optimal. In addition, since the exhaust gas of the specific cylinder # 4 does not directly flow into the catalyst 51 in the EGR execution state, the emission is not deteriorated.

  Further, the exhaust gas recirculation apparatus 1 according to the present embodiment controls the fuel injection amount in the specific cylinder # 4 according to the opening degree of the control valve 25, so that the fuel efficiency is optimal for the air-fuel ratio of the specific cylinder # 4. The air / fuel ratio can be maintained.

  Furthermore, since the exhaust gas recirculation apparatus 1 according to the present embodiment adjusts the amount of air introduced into the specific cylinder # 4 by the control valve 25 in the EGR execution state, it is compared with the case where only the fuel injection amount is adjusted. Thus, the EGR rate can be greatly changed. That is, the adjustment range of the EGR rate can be increased.

  In addition, the exhaust gas recirculation apparatus 1 according to the present embodiment can switch between the EGR execution state and the EGR stop state by adjusting the opening degrees of the exhaust gas recirculation valve 42 and the communication valve 43.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.

  This embodiment is different from the second embodiment in that an exhaust gas recirculation valve 42 and a communication valve 43 are provided. Therefore, the same components as those of the second embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 8, the exhaust gas recirculation device 401 according to the present embodiment includes an exhaust gas recirculation valve 42 and a communication valve 43. The exhaust gas recirculation valve 42 is provided in the exhaust gas recirculation passage 240 a on the downstream side of the EGR cooler 41. The exhaust gas recirculation valve 42 is constituted by an electronically controlled valve, and the opening degree thereof is adjusted according to a command signal from the ECU 100.

  In the present embodiment, the exhaust manifold 30 and the exhaust gas recirculation passage 240a communicate with each other, and a communication valve 43 is provided at the communication portion. The communication valve 43 adjusts the flow rate of the exhaust gas discharged from the exhaust gas recirculation passage 40a to the exhaust manifold 30. The communication valve 43 is configured by an electronically controlled valve, and the opening degree thereof is adjusted according to a command signal from the ECU 100.

  In the present embodiment, the flow rate of EGR gas recirculated from the specific cylinder # 4 to the main intake passage 10a can be adjusted by adjusting the opening degrees of the exhaust gas recirculation valve 42 and the communication valve 43 by the ECU 100. .

  For example, in the EGR execution state, the communication valve 43 may be fully closed and the exhaust gas recirculation valve 42 may be opened. On the other hand, in the EGR stop state, the exhaust gas recirculation valve 42 may be fully closed and the communication valve 43 may be opened.

  According to the exhaust gas recirculation apparatus 401 according to the present embodiment, the following effects can be obtained in addition to the effects described in the third embodiment.

  That is, in the exhaust gas recirculation apparatus 401 according to the present embodiment, since the introduction passage 224a communicates with the main intake passage 10a on the upstream side of the exhaust gas recirculation passage 240a, fresh air that does not contain EGR gas in the EGR execution state. Can be introduced into a specific cylinder # 4. Thereby, the combustion speed in the specific cylinder # 4 can be improved. As a result, combustion in the specific cylinder # 4 can be stabilized, and the air-fuel ratio of the specific cylinder # 4 can be maintained at the air-fuel ratio at which the fuel efficiency is optimal.

  Although the embodiments of the present invention have been disclosed as described above, it is obvious that those skilled in the art can make changes without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

1, 201, 301, 401 Exhaust gas recirculation device 2 Multi-cylinder internal combustion engine 10a Main intake passage 16 Throttle valve 20 Intake manifold 21a, 22a, 23a Branch passage (second intake passage)
24a Branch passage (first intake passage)
25 Control valve 26a, 224a, 226a Introduction passage (first intake passage)
30 Exhaust manifold 31a, 32a, 33a Branch passage (exhaust passage)
40a, 240a Exhaust recirculation passage 42 Exhaust recirculation valve 43 Communication valve 50a Exhaust passage (exhaust passage)
# 1, # 2, # 3 cylinders (cylinders other than specific cylinders)
# 4 cylinder (specific cylinder)

Claims (6)

An exhaust gas recirculation device for recirculating a part of exhaust gas discharged from a multi-cylinder internal combustion engine having a plurality of cylinders to an intake side,
A main intake passage for introducing air into the multi-cylinder internal combustion engine;
A first intake passage that communicates with the main intake passage and introduces air into a specific cylinder of the plurality of cylinders;
A second intake passage that communicates with the main intake passage and introduces air into cylinders other than the specific cylinder;
An exhaust gas recirculation passage for returning the total amount of exhaust gas discharged from the specific cylinder to the main intake passage upstream of the first intake passage and the second intake passage;
A regulating valve for regulating the amount of air introduced into the specific cylinder,
The exhaust gas recirculation apparatus, wherein the control valve is provided in the first intake passage. The first intake passage and the second intake passage constitute an intake manifold that communicates the main intake passage and each of the plurality of cylinders,
The exhaust gas recirculation apparatus according to claim 1, wherein the control valve is provided in the intake manifold. An exhaust gas recirculation device for recirculating a part of exhaust gas discharged from a multi-cylinder internal combustion engine having a plurality of cylinders to an intake side,
A main intake passage for introducing air into the multi-cylinder internal combustion engine;
A first intake passage that communicates with the main intake passage and introduces air into a specific cylinder of the plurality of cylinders;
A second intake passage that communicates with the main intake passage and introduces air into cylinders other than the specific cylinder;
An exhaust gas recirculation passage for recirculating the entire amount of exhaust gas discharged from the specific cylinder to the main intake passage on the downstream side of the first intake passage and on the upstream side of the second intake passage;
A regulating valve for regulating the amount of air introduced into the specific cylinder,
The exhaust gas recirculation apparatus, wherein the control valve is provided in the first intake passage. The main intake passage is provided with a throttle valve for adjusting the amount of air introduced into the multi-cylinder internal combustion engine,
4. The exhaust gas recirculation apparatus according to claim 1, wherein the first intake passage communicates with the main intake passage upstream of the throttle valve. 5. The main intake passage is provided with a throttle valve for adjusting the amount of air introduced into the multi-cylinder internal combustion engine,
4. The exhaust gas recirculation apparatus according to claim 1, wherein the exhaust gas recirculation passage communicates with the main intake air passage at a downstream side of the throttle valve. An exhaust passage for exhausting exhaust gas discharged from cylinders other than the specific cylinder;
The exhaust passage and the exhaust gas recirculation passage communicate with each other;
2. A communication valve for adjusting a flow rate of exhaust gas discharged from the exhaust gas recirculation passage to the exhaust passage is provided at a communication portion between the exhaust passage and the exhaust gas recirculation passage. The exhaust gas recirculation apparatus according to claim 4.

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