JP2003239777A - Egr device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EGR device achieving a high EGR rate in a engine with a turbo-charger. <P>SOLUTION: In the EGR device, part of the exhaust gas 8 from an exhaust manifold 9 of the engine 1 with the turbo-charger 2 is re-circulated to an intake tube 4. The inside of the exhaust manifold 9 is divided by a partition wall 14 to prevent generation of the exhaust interference of each cylinder 7, and, of outlet channels 9A and 9B of the exhaust manifold 9 divided by the partition wall 14, the area of the section of the outlet channel 9B on the side for discharging the exhaust gas 8 for re-circulation is smaller than that of the outlet channel 9A on the side where the exhaust gas 8 is not discharged. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an EGR device.

[0002]

2. Description of the Related Art Conventionally, in an automobile engine or the like, a part of exhaust gas is extracted from the exhaust side and returned to the intake side.
The so-called exhaust gas recirculation (EGR), which suppresses the combustion of fuel in the engine with the exhaust gas returned to the intake side and reduces the generation of NOx by lowering the combustion temperature, is known as EGR (Exhaust Gas Recirculation). Has been done.

Generally, when this kind of exhaust gas recirculation is carried out, between an appropriate position of the exhaust passage extending from the exhaust manifold to the exhaust pipe and an appropriate position of the intake passage extending from the intake pipe to the intake manifold. It is connected by an EGR pipe, and exhaust gas is recirculated through the EGR pipe.

The exhaust gas recirculated to the engine is EG
Cooling in the middle of the R pipe lowers the temperature of the exhaust gas and reduces its volume, so that the combustion temperature is lowered and the generation of nitrogen oxides is effectively reduced without significantly reducing the output of the engine. Therefore, a water-cooled EG is installed in the middle of the EGR pipe that recirculates exhaust gas to the engine.
Some are equipped with an R cooler.

FIG. 4 shows an example of the EGR device for performing the above-mentioned exhaust gas recirculation. In the figure, 1 shows an engine which is a diesel engine, and the engine 1 is equipped with a turbocharger 2. The intake air 3 guided from an air cleaner (not shown) is sent to the compressor 2a of the turbocharger 2 through the intake pipe 4, the intake air 3 pressurized by the compressor 2a is sent to the intercooler 5 to be cooled, and the intake air is further taken from the intercooler 5. The intake air 3 is guided to the manifold 6 and is distributed to the cylinders 7 of the engine 1 (in FIG. 4, the case of inline 6 cylinders is illustrated).

Exhaust gas 8 discharged from each cylinder 7 of the engine 1 is sent to a turbine 2b of the turbocharger 2 via an exhaust manifold 9, and the turbine 2b.
The exhaust gas 8 driven by is discharged to the outside of the vehicle through the exhaust pipe 10.

The EGR pipe 11 is provided between one end of the exhaust manifold 9 in the direction of arrangement of the cylinders 7 and one end of the intake pipe 4 connected to the intake manifold 6.
The exhaust gas 8 is partially connected to the intake manifold 4 and can be guided to the intake pipe 4.

In the EGR pipe 11, the E
An EGR valve 12 that appropriately opens and closes the GR pipe 11, and
EGR cooler 1 for cooling the recirculated exhaust gas 8
In the EGR cooler 13, the temperature of the exhaust gas 8 can be lowered by exchanging heat between cooling water (not shown) and the exhaust gas 8.

Reference numeral 14 in FIG. 4 denotes a partition wall that divides the exhaust passages for the front three cylinders and the exhaust passages for the rear three cylinders in the exhaust manifold 9, and the partition wall 14 makes one of the exhaust strokes. Exhaust pulsation is efficiently sent to the turbine 2b by suppressing exhaust interference between the cylinders 7 having overlapping parts.

[0010]

However, in the EGR device equipped in the engine 1 with the turbocharger 2 as described above, the pressure difference between the intake side and the exhaust side becomes small because the intake side is supercharged. However, there is a problem that it is difficult to realize a high EGR rate.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an EGR device capable of realizing a high EGR rate even in an engine equipped with a turbocharger.

[0012]

According to the present invention, a part of exhaust gas is extracted from an exhaust manifold of an engine equipped with a turbocharger and is recirculated to an intake pipe.
In the R device, the exhaust manifold is partitioned by a partition wall so that exhaust interference of each cylinder does not occur, and a side of the exhaust manifold outlet flow path divided by the partition wall that extracts the recirculation exhaust gas is The flow passage cross-sectional area is smaller than that on the side on which the exhaust gas for recirculation is not extracted.

Thus, in this way, the back pressure in the outlet passage on the side where the exhaust gas for recirculation is extracted is the back pressure in the outlet passage on the side where the exhaust gas for recirculation is not extracted. As a result of being further increased, even if the intake side is supercharged, a sufficient pressure difference with the exhaust side is secured, and a higher EGR rate than in the past is realized.

In the present invention, the recirculation exhaust gas is extracted with respect to the fuel injection amount of each cylinder communicating with the outlet passage on the side where the recirculation exhaust gas is not extracted. A fuel injection control unit that controls the fuel injection amount of each cylinder communicating with the outlet passage to be relatively small may be provided.

With this configuration, even if the back pressure in the outlet passage on the side where the exhaust gas for recirculation is extracted is increased, the fuel injection amount of each cylinder communicating with the outlet passage is suppressed. As a result, the possibility that the amount of residual gas in each cylinder will increase can be avoided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an example of a mode for carrying out the present invention, and the parts denoted by the same reference numerals as those in FIG. 4 represent the same parts.

As shown in FIGS. 1 and 2, in this embodiment, the exhaust manifold 9 divided by the partition wall 14 does not extract the exhaust gas 8 for recirculation (the EGR pipe 11 is not connected). The outlet flow passage 9A on the side) is formed with the same flow passage cross-sectional area as the conventional one, while the exhaust gas 8 for recirculation is extracted (the EGR pipe 11).
The outlet flow channel 9B (on the side to which is connected) is narrowed down so that the cross-sectional area of the flow channel is smaller than in the conventional case.

That is, the outlet passages 9A and 9B of the conventional exhaust manifold 9 are divided into two equal parts by the partition wall 14 so that they have the same passage cross-sectional area as shown in FIG. The flow passage cross-sectional area of the passage 9B is made smaller than that on the outlet flow passage 9A side.

When the flow passage cross-sectional area of the outlet flow passage 9B is narrowed down from the conventional structure, the shape of the outlet portion of the exhaust manifold 9 and the inlet portion of the turbine 2b of the turbocharger 2 should be changed in advance. Good, but for example
It is also possible to equip with some kind of flow passage restricting means for narrowing down the flow passage cross-sectional area of the outlet flow passage 9B, and further, the flow passage restricting means can be constituted by a damper which can be opened and closed to adjust the opening degree. It may be a different structure.

Further, in the example shown here,
For the injectors 15 of the three cylinders 7 on the front side of the engine 1, an engine control computer (ECU: Electronic C
On the other hand, a fuel injection signal 16a for instructing an injection amount (a valve opening time of a solenoid valve) in the conventional manner at an appropriate timing is output from a control device 16 (fuel injection control means) which constitutes an ontrol unit). To the injectors 15 of the three rear cylinders 7 of the engine 1, a fuel injection signal 16b for instructing a smaller injection amount (opening time of the solenoid valve) at a proper timing than before is output from the control device 16. It has become so.

If the EGR device is constructed in this way, the back pressure in the outlet passage 9B on the side where the exhaust gas 8 for recirculation is extracted causes the exhaust gas 8 for recirculation to be extracted. As a result of being higher than the back pressure of the outlet flow passage 9A on the non-exhaust side, a sufficient pressure difference with the exhaust side can be secured even if the intake side is supercharged, and a higher EGR rate than before can be realized. Become.

Further, the fuel injection amount of each injector 15 is controlled by the control device 16, and the fuel injection amount of each cylinder 7 communicating with the outlet passage 9A is different from the fuel injection amount of each cylinder 7 communicating with the outlet passage 9B. Since the fuel injection amount of No. 7 is suppressed, even if the back pressure in the outlet passage 9B is increased, the amount of residual gas in each cylinder 7 communicating with the outlet passage 9B may increase. Is avoided in advance.

Therefore, according to the above embodiment, it is possible to secure a sufficient pressure difference between the intake side and the exhaust side even if the intake side is supercharged. Therefore, the engine 1 equipped with the turbocharger 2
In this case, a high EGR rate can be realized and it is possible to comply with strict exhaust gas regulations in the future.

Further, regarding each cylinder 7 communicating with the outlet passage 9B on the side for extracting the exhaust gas 8 for recirculation,
Since it is possible to avoid the possibility that the amount of the residual gas will increase, it is possible to prevent the smoke from worsening due to the uneven distribution of the residual gas in the cylinder 7.

The EGR device of the present invention is not limited to the above-described embodiment, and the target engine is not limited to the in-line 6-cylinder, and within the range not departing from the gist of the present invention. Of course, various changes can be made.

[0027]

According to the EGR device of the present invention described above,
Various excellent effects as described below can be obtained.

(I) According to the first aspect of the present invention, even if the intake side is supercharged, a sufficient pressure difference between the intake side and the exhaust side can be ensured, so an engine equipped with a turbocharger. In this case, a high EGR rate can be realized and it is possible to comply with strict exhaust gas regulations in the future.

(II) According to the second aspect of the present invention, with respect to each cylinder communicating with the outlet passage on the side for extracting the exhaust gas for recirculation, the residual gas amount increases. Since the fear can be avoided in advance, it is possible to prevent the smoke from being deteriorated due to the uneven distribution of the residual gas in the cylinder.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of an embodiment for carrying out the present invention.

2 is a cross-sectional view of the outlet flow path of the exhaust manifold of FIG.

FIG. 3 is a cross-sectional view of an outlet passage of a conventional exhaust manifold.

FIG. 4 is a schematic view showing a conventional example.

[Explanation of symbols]

1 engine 2 turbocharger 4 intake pipe 7 cylinders 8 exhaust gas 9 Exhaust manifold 9A outlet flow path 9B outlet flow path 10 exhaust pipe 14 partitions 16 Control device (fuel injection control means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 41/02 F02D 41/02 380E 43/00 301 43/00 301G 301N 301R F02M 25/07 550 F02M 25 / 07 550R 570 570J 570P (72) Inventor Kiyohiro Shimokawa 3-1-1 Hinodai, Hino-shi, Tokyo 1 Hino Motors Co., Ltd. F term (reference) 3G062 AA01 AA03 AA05 BA04 CA06 DA01 DA02 EA04 EA10 ED08 FA4 FA03 3G06 AA01 AA03 BA08 BA13 BA20 CA03 CA04 DA10 EA04 EB01 EC01 EC03 3G092 AA02 AA06 AA13 AA17 AA18 BB01 DB03 DC08 DE03S DG06 DG07 EA01 EA02 EB05 EC07 FA17 LC11 GA02 GA01 GA01 GA01 GA01 GA11 GA01 GA13 GA05 GA06 3 NE06

Claims (2)

[Claims] 1. An EGR device in which part of exhaust gas is extracted from an exhaust manifold of an engine equipped with a turbocharger and recirculated to an intake pipe, and exhaust interference of each cylinder does not occur in the exhaust manifold. The exhaust gas outlet side of the exhaust manifold, which is divided by the partition wall as described above, on which the exhaust gas for recirculation is extracted is a cross-sectional area of the flow path that is larger than the side on which the exhaust gas for recirculation is not extracted. An EGR device characterized in that 2. The fuel injection quantity of each cylinder communicating with the outlet passage on the side where the exhaust gas for recirculation is not extracted is communicated with the outlet passage on the side where the exhaust gas for recirculation is extracted. The EGR device according to claim 1, further comprising a fuel injection control unit that controls so that the fuel injection amount of each of the operating cylinders becomes relatively small.