JPH09195860A - Erg gas supply device for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ERG gas supply device for a diesel engine in which sufficient amount ERG gas can be supplied without the significant influence of the opening and closing conditions of a throttle valve. SOLUTION: An ERG gas supply device is composed of an intake pipe 10 which introduces intake air to a diesel engine, an intake throttle portion 12 which is provided with a throttle valve 2 for intake amount adjustment in the intake pipe 10, and an ERG gas supply port 3 which supplies ERG gas in the intake pipe 10. The intake throttle portion 13 and an ERG gas supply portion 12 are arranged in parallel in an orthogonal direction to a lengthwise direction in the intake pipe 10 via a partition plate 15, a venturi portion 33 is provided in the ERG gas supply portion 13, and an ERG supply pipe 3 introducing ERG gas into the venturi portion 33 is opened therein.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a diesel engine,
The present invention relates to an EGR gas supply device for supplying exhaust gas recirculation gas (EGR gas) to an intake pipe.

[0002]

2. Description of the Related Art Conventionally, in diesel engines, EG
As an apparatus for supplying R gas to the intake pipe, for example, there is an EGR gas supply apparatus 9 having a structure as shown in FIG.
As shown in FIG. 8, the EGR gas supply device 9 is provided with a throttle valve 92 inside an intake pipe 91 for introducing intake air into the engine, and an EGR gas supply pipe 93 is opened.

As shown in FIG. 8, the throttle valve 92 opens and closes in conjunction with the movement of the accelerator pedal 8 on the driver's side to adjust the intake air amount. Further, the EGR gas supply pipe 93 is
As shown in FIG. 8, the EGR valve 95 and the connecting pipe 96
Through the exhaust manifold 97 on the exhaust system side. The EGR valve 95 closes the connecting pipes 94 and 96 to shut off the EGR gas passage when the EGR gas is not needed, and opens to connect the EGR gas passage when the EGR gas is supplied.

When the EGR gas supply device 9 supplies the EGR gas, the fact that the inside of the intake pipe 91 becomes negative due to the intake flow due to the operation of the engine is utilized. Specifically, the pressure on the exhaust system side and the intake pipe 91
The EGR gas is sucked out from the EGR gas supply pipe 93 by the pressure difference from the internal pressure and supplied to the engine.

[0005]

[Problems to be Solved] However, the above-mentioned conventional E
The GR gas supply device 9 has the following problems. That is, it is difficult to secure a sufficient supply amount of EGR gas because the intake negative pressure is low when the engine is running at a low speed or is operated under a light load. Further, the throttle valve 92
When is rapidly opened and closed, the intake flow on the downstream side of the throttle valve 92 is disturbed and the pressure is greatly changed. Especially,
When the throttle valve 92 is suddenly opened, its downstream side,
That is, the pressure near the EGR gas supply pipe 93 rapidly increases. Therefore, the supply amount of EGR gas is significantly reduced.

As a countermeasure against this, for example, actual Kaihei 2-119
As shown in Japanese Patent No. 963, a deflecting member for deflecting the intake flow is arranged inside the intake pipe on the downstream side of the throttle valve,
It has been proposed to form a so-called Venturi portion and increase the intake speed at the opening position of the EGR gas supply pipe to secure the supply amount of EGR gas. However, according to this means, when the opening of the throttle valve is small, turbulence occurs in the flow of intake air immediately after the throttle valve.
The air passing through the opening position of the GR gas supply pipe is also disturbed,
The EGR gas cannot be supplied smoothly.

The present invention has been made in view of the above conventional problems, and is capable of supplying a sufficient amount of EGR gas without being largely affected by the opening / closing state of the throttle valve, and is an EGR for a diesel engine. It is intended to provide a gas supply device.

[0008]

According to a first aspect of the present invention, an intake pipe for introducing intake air into a diesel engine, an intake throttle portion provided with a throttle valve for adjusting an intake amount in the intake pipe, and E
An EGR gas supply unit for supplying GR gas into the intake pipe, and the intake throttle unit and the EGR gas supply unit are arranged in the intake pipe via a partition plate in a direction orthogonal to the longitudinal direction thereof. Are arranged in parallel,
The EGR gas supply unit for a diesel engine is characterized in that a venturi part is provided in the EGR gas supply part, and an EGR gas supply pipe for introducing the EGR gas into the venturi part is opened. is there.

What is most noticeable in the present invention is that a part of the intake pipe is divided into two systems by the partition plate, and the intake throttle part is formed in one of them and the EGR gas supply part is formed in parallel with the other. In addition, the EGR gas supply section is formed with a venturi section in which the EGR gas supply pipe is opened.

The venturi portion having the EGR gas supply pipe opened is a portion in which the passage of intake air in the EGR gas supply portion is narrowed and has a characteristic that the intake speed is the highest and the negative pressure is obtained. Therefore, the EGR gas is easily sucked into the intake pipe in this venturi portion.

The cross-sectional area of the intake passage of the EGR gas supply section is preferably 30 to 50% of the total cross-sectional area of the intake pipe. If it is less than 30%, there is a problem that when the throttle valve for adjusting the intake air amount is opened, the intake air to the EGR gas supply unit becomes small, a sufficient Venturi negative pressure cannot be obtained, and EGR gas cannot be used. On the other hand, if it exceeds 50%, there is a problem that the venturi portion becomes an intake resistance and the output becomes insufficient.

The cross-sectional area of the intake passage of the venturi portion is preferably 60 to 80% of the cross-sectional area of the EGR gas supply portion. If it is less than 60%, there is a problem that the amount of intake air is small and the output becomes insufficient. On the other hand, if it exceeds 80%, there is a problem that a sufficient Venturi negative pressure cannot be obtained and it becomes difficult to suck EGR gas. .

Next, the operation of the present invention will be described. In the EGR gas supply device for the diesel engine of the present invention, the partition plate is provided in the intake pipe as described above.
Intake throttle part with throttle valve and EG
And an EGR gas supply section in which the R gas supply pipe is opened,
They are provided in parallel in the direction orthogonal to the longitudinal direction.

Therefore, even if turbulence of the intake flow and pressure fluctuation occur on the downstream side of the throttle valve due to a rapid change in the opening of the throttle valve, the EGR gas supply section located in another system is not affected. . Therefore, the intake air always flows smoothly in the EGR gas supply unit to maintain a stable intake negative pressure state. Therefore, the EGR gas supply can be stabilized.

The venturi portion is provided in the EGR gas supply portion, and the EGR gas supply portion is provided with the EGR gas.
The gas supply pipe is open. Therefore, the intake air flowing into the EGR gas supply unit flows at the highest speed at the opening position of the EGR gas supply pipe and has the lowest negative pressure state. Therefore, the EGR gas is sufficiently sucked into the intake pipe, and the supply amount thereof is sufficiently secured.

Next, as in the invention of claim 2, the EG
The open end of the R gas supply pipe is preferably open toward the downstream side of the intake flow. As a result, the negative pressure state at the open end of the EGR gas supply pipe can be used more efficiently, and the supply of EGR gas can be further stabilized. In addition, as the shape of the opening end,
For example, as shown in FIGS. 5 and 6 which will be described later, various shapes can be adopted, such as one in which the pipe is cut obliquely, one in which a part of the downstream side wall surface of the pipe whose tip is sealed is cut out.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

Example Embodiment 1 E for a diesel engine according to an example embodiment of the present invention
The GR gas supply device will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, an EGR gas supply device 1 for a diesel engine of this example is provided with an intake pipe 10 for introducing intake air into the diesel engine, and a throttle valve 2 for adjusting the intake air amount in the intake pipe 10. Intake throttle section 12, E
The EGR gas supply unit 13 is provided for supplying the GR gas into the intake pipe 10.

The intake throttle portion 12 and the EGR gas supply portion 13 are arranged in parallel in the intake pipe 10 with a partition plate 15 in a direction orthogonal to the longitudinal direction of the intake pipe 10.
In addition, the EGR gas supply unit 13 is provided with a venturi unit 33, and the EGR gas supply pipe 3 for introducing the EGR gas into the Venturi unit 33 is opened.

This will be described in detail below. The intake pipe 10 is connected to the intake manifold 4 on the engine side as shown in FIG. Further, the intake pipe 10 is provided with a partition plate 15 along the intake flow at the tip thereof.
The inside of the engine is divided into two systems, and the intake throttle 12
And the EGR gas supply unit 13 are provided in parallel on the other side.

A throttle valve 2 arranged in the intake throttle section 12
Is fixed to the rotary shaft 21 as shown in FIGS. The rotary shaft 21 is rotated by a drive system via an RPS (rotary position sensor) that detects the opening of the accelerator pedal 8 on the driver's side.

As shown in FIG. 1, the EGR gas supply unit 13 has a projection 153, which is a projection of the partition plate 15 and a part of the intake pipe 10 so as to be close to each other in their entire width.
By providing 103, the venturi portion 33 is formed. Then, the EG arranged in the venturi portion 33
As shown in FIG. 1, the R gas supply pipe 3 is connected to an exhaust manifold 97 of the exhaust system via an EGR valve 95 and a connecting pipe 96.

The EGR valve 95, as shown in FIG.
VSV (vacuum switching valve) 5 controlled by an ECU (electric control unit) 56
The vacuum pump 55 is connected via 7 and is configured to open and close by the negative pressure generated by the vacuum pump 55. The opening and opening / closing timing of the EGR valve 55 are calculated and determined by the ECU 56 based on data such as accelerator opening, water temperature, atmospheric pressure, engine speed, etc., and the VSV 57 adjusts based on this.

Next, the operation of this embodiment will be described. In the EGR gas supply device 1 for the diesel engine of this example, the inside of the intake pipe 10 is divided by the partition plate as described above.
Intake throttle section 12 divided into systems and having throttle valve 2
And an EGR gas supply unit 13 having an EGR gas supply pipe 3 opened are provided in parallel in a direction orthogonal to the longitudinal direction.

Therefore, even if the intake flow turbulence or the pressure fluctuation occurs on the downstream side of the throttle valve 2 due to the rapid change of the opening degree of the throttle valve 2, the EGR gas supply unit 13 located in another system is affected. Does not reach. Therefore, the intake air always flows smoothly in the EGR gas supply unit 13, and a stable intake negative pressure state is maintained. Therefore, the EGR gas supply can be stabilized.

Further, the EGR gas supply section 13 is provided with a venturi section 33, and this venturi section 33 has
The EGR gas supply pipe 3 is opened. for that reason,
The intake air that has flown into the EGR gas supply unit 13 flows at the highest speed at the opening position of the EGR gas supply pipe 3 and is in the lowest negative pressure state. Therefore, the EGR gas is sufficiently sucked and the supply amount thereof is sufficiently secured.

Embodiment 2 In this embodiment, as shown in FIGS. 3 to 5, the opening end of the EGR gas supply pipe 3 in Embodiment 1 is opened toward the downstream side. Specifically, as shown in FIGS. 3 to 5, the tip of the EGR gas supply pipe 3 is attached to the venturi portion 33.
It is projected to. An opening end 132 is provided at the tip of the EGR gas supply pipe 3 by obliquely cutting the portion facing the downstream side of the intake pipe. Others are the same as those in the first embodiment. In this case, the negative pressure of the venturi portion 33 can be used more efficiently, and further, the EGR
It is possible to secure a sufficient gas supply amount.

Embodiment 3 In this embodiment, as shown in FIGS. 6 and 7, the EGR gas supply pipe 3 is projected to the venturi portion as in Embodiment 2. And, in the EGR gas supply pipe 3,
The tip was sealed and a part of the wall surface on the downstream side was cut out,
An open end 133 is provided. Others are the same as those in the first embodiment. Also in this case, the same effect as that of the second embodiment can be obtained.

[0028]

As described above, according to the present invention, it is possible to obtain an EGR gas supply device for a diesel engine which can supply a sufficient amount of EGR gas without being largely influenced by the opening / closing state of the throttle valve. You can

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of an EGR gas supply device according to a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is an explanatory diagram showing a main configuration of an EGR gas supply device according to a second embodiment.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is an explanatory view showing an opening end shape of an EGR gas supply pipe in the second embodiment.

FIG. 6 is an explanatory diagram showing a main configuration of an EGR gas supply device according to a third embodiment.

FIG. 7 is an explanatory diagram showing an open end shape of an EGR gas supply pipe according to the third embodiment.

FIG. 8 is an explanatory diagram showing the configuration of a conventional EGR gas supply device.

[Explanation of symbols]

 1. . . EGR gas supply device, 10. . . Intake pipe, 12. . . Intake throttle part, 13. . . EGR gas supply unit, 15. . . Partition board, 2. . . Throttle valve, 3. . . EGR gas supply pipe, 33. . . Venturi Department,

Claims (2)

[Claims] 1. An intake pipe for introducing intake air into a diesel engine, an intake throttle portion provided with a throttle valve for adjusting an intake amount in the intake pipe, and an EGR for supplying EGR gas into the intake pipe. A gas supply unit, the intake throttle unit and the EGR gas supply unit are arranged in parallel in the intake pipe in a direction orthogonal to the longitudinal direction thereof via a partition plate, and the EGR gas supply unit An EGR gas supply device for a diesel engine, characterized in that a venturi portion is provided in the portion, and an EGR gas supply pipe for introducing the EGR gas is opened in the venturi portion. 2. The EGR gas supply device for a diesel engine according to claim 1, wherein an opening end of the EGR gas supply pipe is opened toward a downstream side.